mir/postfix
2
0
Fork 0
mirror of https://github.com/vdukhovni/postfix synced 2025-08-29 13:18:12 +00:00
Code Issues Releases Wiki Activity

postfix-3.6-20200725

Browse Source
This commit is contained in:
Wietse Venema 2020-07-25 00:00:00 -05:00 committed by Viktor Dukhovni
parent bf6bdb562d
commit 04f880d08a
25 changed files with 1048 additions and 651 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
postfix/HISTORY
View File

@ -25008,3 +25008,18 @@ Apologies for any names omitted.
Final cleanups of the peername matching code. File: Final cleanups of the peername matching code. File:
tls/tls_client.c. tls/tls_client.c.
202000725
Documentation of how to set the minimum and maximum allowed
TLS protocol versions (these override system-wide OpenSSL
configuration), some related code cleanups including better
warning messages. Viktor Dukhovni. Files: proto/TLS_README.html,
proto/postconf.proto, global/mail_params.h,
posttls-finger/posttls-finger.c, tls/tls.h, tls/tls_client.c,
tls/tls_fprint.c, tls/tls_misc.c, tls/tls_server.c.
The Postfix TLS library did not override the system-wide
OpenSSL configuration of allowed TLS protocol versions, for
sessions where the remote SMTP client sends SNI. File:
tls/tls_server.c.

51
postfix/README_FILES/TLS_README
View File

@ -101,10 +101,10 @@ SMTP server configurations will not accidentally enable TLS without
certificates. certificates.
Note that server certificates are nnoott optional in TLS 1.3. To run without Note that server certificates are nnoott optional in TLS 1.3. To run without
certificates you'd have to disable the TLS 1.3 protocol by including '!TLSv1.3' certificates you'd have to disable the TLS 1.3 protocol by including
in "smtpd_tls_protocols" and perhaps also "smtpd_tls_mandatory_protocols". It "<=TLSv1.2" (or, for Postfix < 3.6, "!TLSv1.3") in "smtpd_tls_protocols" and
is simpler instead to just configure a certificate chain. Certificate-less perhaps also "smtpd_tls_mandatory_protocols". It is simpler instead to just
operation is not recommended. configure a certificate chain. Certificate-less operation is not recommended.
RSA, DSA and ECDSA (Postfix >= 2.6) certificates are supported. Most sites only RSA, DSA and ECDSA (Postfix >= 2.6) certificates are supported. Most sites only
have RSA certificates. You can configure all three at the same time, in which have RSA certificates. You can configure all three at the same time, in which
@ -632,8 +632,8 @@ With mandatory and opportunistic TLS encryption, the Postfix SMTP server by
default disables SSLv2 and SSLv3 with Postfix releases after the middle of default disables SSLv2 and SSLv3 with Postfix releases after the middle of
2015; older releases only disable SSLv2 for mandatory TLS. The mandatory TLS 2015; older releases only disable SSLv2 for mandatory TLS. The mandatory TLS
protocol list is specified via the smtpd_tls_mandatory_protocols configuration protocol list is specified via the smtpd_tls_mandatory_protocols configuration
parameter. The smtpd_tls_protocols parameter (Postfix >= 2.6) controls the SSL/ parameter. The smtpd_tls_protocols parameter (Postfix >= 2.6) controls the TLS
TLS protocols used with opportunistic TLS. protocols used with opportunistic TLS.
Note that the OpenSSL library only supports protocol exclusion (not inclusion). Note that the OpenSSL library only supports protocol exclusion (not inclusion).
For this reason, Postfix can exclude only protocols that are known at the time For this reason, Postfix can exclude only protocols that are known at the time
@ -649,8 +649,7 @@ configurations may not interoperate with some clients, and require that TLSv1.3
be explicitly disabled. Therefore, they are not recommended, it is better and be explicitly disabled. Therefore, they are not recommended, it is better and
simpler to just configure a suitable certificate. simpler to just configure a suitable certificate.
Example, MSA that requires TLSv1 or higher, not SSLv2 or SSLv3, with high grade Example, MSA that requires TLSv1.2 or higher, with high grade ciphers:
ciphers:
/etc/postfix/main.cf: /etc/postfix/main.cf:
smtpd_tls_cert_file = /etc/postfix/cert.pem smtpd_tls_cert_file = /etc/postfix/cert.pem
@ -658,10 +657,10 @@ ciphers:
smtpd_tls_mandatory_ciphers = high smtpd_tls_mandatory_ciphers = high
smtpd_tls_mandatory_exclude_ciphers = aNULL, MD5 smtpd_tls_mandatory_exclude_ciphers = aNULL, MD5
smtpd_tls_security_level = encrypt smtpd_tls_security_level = encrypt
# Preferred syntax with Postfix >= 2.5: # Preferred syntax with Postfix >= 3.6:
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_mandatory_protocols = >=TLSv1.2
# Legacy syntax: # Legacy syntax:
smtpd_tls_mandatory_protocols = TLSv1 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
With Postfix >= 3.4, specify instead a single file that holds the key followed With Postfix >= 3.4, specify instead a single file that holds the key followed
by the corresponding certificate and any associated issuing certificates, by the corresponding certificate and any associated issuing certificates,
@ -924,9 +923,10 @@ not specified consistently.
submission submission
/etc/postfix/tls_policy: /etc/postfix/tls_policy:
[example.net]:587 encrypt protocols=TLSv1 ciphers=high # Postfix >= 3.6 "protocols" syntax
[example.net]:msa encrypt protocols=TLSv1 ciphers=high [example.net]:587 encrypt protocols=>=TLSv1.2 ciphers=high
[example.net]:submission encrypt protocols=TLSv1 ciphers=high # Legacy "protocols" syntax
[example.net]:msa encrypt protocols=!SSLv2:!SSLv3 ciphers=high
DDAANNEE TTLLSS aauutthheennttiiccaattiioonn.. DDAANNEE TTLLSS aauutthheennttiiccaattiioonn..
@ -1835,8 +1835,11 @@ Example:
[thumb.example.org] fingerprint [thumb.example.org] fingerprint
match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f
match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76 match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76
# Postfix 2.6 and later # Postfix >= 3.6 "protocols" syntax
example.info may protocols=!SSLv2 ciphers=medium example.info may protocols=>=TLSv1 ciphers=medium
exclude=3DES
# Legacy protocols syntax
example.info may protocols=!SSLv2:!SSLv3 ciphers=medium
exclude=3DES exclude=3DES
NNoottee:: The "hostname" strategy if listed in a non-default setting of NNoottee:: The "hostname" strategy if listed in a non-default setting of
@ -1909,8 +1912,8 @@ the minimum opportunistic TLS cipher grade is always "export".
With mandatory and opportunistic TLS encryption, the Postfix SMTP client will With mandatory and opportunistic TLS encryption, the Postfix SMTP client will
by default disable SSLv2 and SSLv3. The mandatory TLS protocol list is by default disable SSLv2 and SSLv3. The mandatory TLS protocol list is
specified via the smtp_tls_mandatory_protocols configuration parameter. The specified via the smtp_tls_mandatory_protocols configuration parameter. The
corresponding smtp_tls_protocols parameter (Postfix >= 2.6) controls the SSL/ corresponding smtp_tls_protocols parameter (Postfix >= 2.6) controls the TLS
TLS protocols used with opportunistic TLS. protocols used with opportunistic TLS.
Example: Example:
@ -1918,13 +1921,13 @@ Example:
smtp_tls_mandatory_ciphers = medium smtp_tls_mandatory_ciphers = medium
smtp_tls_mandatory_exclude_ciphers = RC4, MD5 smtp_tls_mandatory_exclude_ciphers = RC4, MD5
smtp_tls_exclude_ciphers = aNULL smtp_tls_exclude_ciphers = aNULL
# Preferred form with Postfix >= 2.5:
smtp_tls_mandatory_protocols = !SSLv2
# Legacy form for Postfix < 2.5:
smtp_tls_mandatory_protocols = SSLv3, TLSv1
# Also available with Postfix >= 2.6:
smtp_tls_ciphers = medium smtp_tls_ciphers = medium
smtp_tls_protocols = !SSLv2 # Preferred form with Postfix >= 3.6:
smtp_tls_mandatory_protocols = >=TLSv1.2
smtp_tls_protocols = >=TLSv1
# Legacy form for Postfix < 3.6:
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_protocols = !SSLv2,!SSLv3
CClliieenntt--ssiiddee SSMMTTPPSS ssuuppppoorrtt CClliieenntt--ssiiddee SSMMTTPPSS ssuuppppoorrtt

47
postfix/html/TLS_README.html
View File

@ -179,10 +179,10 @@ configurations will not accidentally enable TLS without certificates. </p>
<p> Note that server certificates are <b>not</b> optional in TLS 1.3. To <p> Note that server certificates are <b>not</b> optional in TLS 1.3. To
run without certificates you'd have to disable the TLS 1.3 protocol by run without certificates you'd have to disable the TLS 1.3 protocol by
including '!TLSv1.3' in "<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a>" and perhaps also including "&lt;=TLSv1.2" (or, for Postfix &lt; 3.6, "!TLSv1.3") in
"<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a>". It is simpler instead to just "<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a>" and perhaps also "<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a>".
configure a certificate chain. Certificate-less operation is not It is simpler instead to just configure a certificate chain.
recommended. <p> Certificate-less operation is not recommended. <p>
<p> RSA, DSA and ECDSA (Postfix &ge; 2.6) certificates are supported. <p> RSA, DSA and ECDSA (Postfix &ge; 2.6) certificates are supported.
Most sites only have RSA certificates. You can configure all three Most sites only have RSA certificates. You can configure all three
@ -891,7 +891,7 @@ after the middle of 2015; older releases only disable SSLv2 for
mandatory TLS. The mandatory TLS protocol list is specified via the mandatory TLS. The mandatory TLS protocol list is specified via the
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> configuration parameter. The <a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> configuration parameter. The
<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> parameter (Postfix &ge; 2.6) <a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> parameter (Postfix &ge; 2.6)
controls the SSL/TLS protocols used with opportunistic TLS. </p> controls the TLS protocols used with opportunistic TLS. </p>
<p> Note that the OpenSSL library only supports protocol exclusion <p> Note that the OpenSSL library only supports protocol exclusion
(not inclusion). For this reason, Postfix can exclude only protocols (not inclusion). For this reason, Postfix can exclude only protocols
@ -909,8 +909,8 @@ that TLSv1.3 be explicitly disabled. Therefore, they are not
recommended, it is better and simpler to just configure a suitable recommended, it is better and simpler to just configure a suitable
certificate. </p> certificate. </p>
<p> Example, MSA that requires TLSv1 or higher, not SSLv2 or SSLv3, <p> Example, MSA that requires TLSv1.2 or higher, with high grade
with high grade ciphers: </p> ciphers: </p>
<blockquote> <blockquote>
<pre> <pre>
@ -920,10 +920,10 @@ with high grade ciphers: </p>
<a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> = high <a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_mandatory_ciphers</a> = high
<a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> = aNULL, MD5 <a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_mandatory_exclude_ciphers</a> = aNULL, MD5
<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> = encrypt <a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a> = encrypt
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = &gt;=TLSv1.2
# Legacy syntax: # Legacy syntax:
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = TLSv1 <a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
</blockquote> </blockquote>
@ -1263,9 +1263,10 @@ just in case the transport table entries are not specified consistently. </p>
submission 587/tcp msa # mail message submission submission 587/tcp msa # mail message submission
/etc/postfix/tls_policy: /etc/postfix/tls_policy:
[example.net]:587 encrypt protocols=TLSv1 ciphers=high # Postfix &ge; 3.6 "protocols" syntax
[example.net]:msa encrypt protocols=TLSv1 ciphers=high [example.net]:587 encrypt protocols=&gt;=TLSv1.2 ciphers=high
[example.net]:submission encrypt protocols=TLSv1 ciphers=high # Legacy "protocols" syntax
[example.net]:msa encrypt protocols=!SSLv2:!SSLv3 ciphers=high
</pre> </pre>
</blockquote> </blockquote>
@ -2398,8 +2399,10 @@ Example:
[thumb.example.org] fingerprint [thumb.example.org] fingerprint
match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f
match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76 match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76
# Postfix 2.6 and later # Postfix &ge; 3.6 "protocols" syntax
example.info may protocols=!SSLv2 ciphers=medium exclude=3DES example.info may protocols=&gt;=TLSv1 ciphers=medium exclude=3DES
# Legacy protocols syntax
example.info may protocols=!SSLv2:!SSLv3 ciphers=medium exclude=3DES
</pre> </pre>
</blockquote> </blockquote>
@ -2494,7 +2497,7 @@ SMTP client will by default disable SSLv2 and SSLv3. The mandatory
TLS protocol list is specified via the TLS protocol list is specified via the
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> configuration parameter. The corresponding <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> configuration parameter. The corresponding
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> parameter (Postfix &ge; 2.6) controls <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> parameter (Postfix &ge; 2.6) controls
the SSL/TLS protocols used with opportunistic TLS. </p> the TLS protocols used with opportunistic TLS. </p>
<p> Example: </p> <p> Example: </p>
@ -2504,13 +2507,13 @@ the SSL/TLS protocols used with opportunistic TLS. </p>
<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = medium <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = medium
<a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> = RC4, MD5 <a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> = RC4, MD5
<a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = aNULL <a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> = aNULL
# Preferred form with Postfix &ge; 2.5:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2
# Legacy form for Postfix &lt; 2.5:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = SSLv3, TLSv1
# Also available with Postfix &ge; 2.6:
<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = medium <a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = medium
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2 # Preferred form with Postfix &ge; 3.6:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=TLSv1.2
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = &gt;=TLSv1
# Legacy form for Postfix &lt; 3.6:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2,!SSLv3
</pre> </pre>
</blockquote> </blockquote>

12
postfix/html/lmtp.8.html
View File

@ -508,9 +508,9 @@ SMTP(8) SMTP(8)
policy by next-hop destination; when a non-empty value is speci- policy by next-hop destination; when a non-empty value is speci-
fied, this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter. fied, this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter.
<b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (see 'postconf -d' output)</b>
List of SSL/TLS protocols that the Postfix SMTP client will use TLS protocols that the Postfix SMTP client will use with manda-
with mandatory TLS encryption. tory TLS encryption.
<b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b> <b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b>
The verification depth for remote SMTP server certificates. The verification depth for remote SMTP server certificates.
@ -573,9 +573,9 @@ SMTP(8) SMTP(8)
Available in Postfix version 2.6 and later: Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (see postconf -d output)</b>
List of TLS protocols that the Postfix SMTP client will exclude TLS protocols that the Postfix SMTP client will use with oppor-
or include with opportunistic TLS encryption. tunistic TLS encryption.
<b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (medium)</b> <b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (medium)</b>
The minimum TLS cipher grade that the Postfix SMTP client will The minimum TLS cipher grade that the Postfix SMTP client will

411
postfix/html/postconf.5.html
View File

@ -5420,7 +5420,7 @@ configuration parameter. See there for details. </p>
</DD> </DD>
<DT><b><a name="lmtp_tls_mandatory_protocols">lmtp_tls_mandatory_protocols</a> <DT><b><a name="lmtp_tls_mandatory_protocols">lmtp_tls_mandatory_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see postconf -d output)</b></DT><DD>
<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> <p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a>
configuration parameter. See there for details. </p> configuration parameter. See there for details. </p>
@ -5464,7 +5464,7 @@ configuration parameter. See there for details. </p>
</DD> </DD>
<DT><b><a name="lmtp_tls_protocols">lmtp_tls_protocols</a> <DT><b><a name="lmtp_tls_protocols">lmtp_tls_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see postconf -d output)</b></DT><DD>
<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> configuration <p> The LMTP-specific version of the <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> configuration
parameter. See there for details. </p> parameter. See there for details. </p>
@ -12881,74 +12881,92 @@ attribute. See <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_ma
</DD> </DD>
<DT><b><a name="smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> <DT><b><a name="smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see "postconf -d" output)</b></DT><DD>
<p> List of SSL/TLS protocols that the Postfix SMTP client will use with <p> TLS protocols that the Postfix SMTP client will use with mandatory
mandatory TLS encryption. In <a href="postconf.5.html">main.cf</a> the values are separated by TLS encryption. In <a href="postconf.5.html">main.cf</a> the values are separated by whitespace,
whitespace, commas or colons. In the policy table "protocols" attribute commas or colons. In the policy table "protocols" attribute (see
(see <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid separator is colon. An <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid separator is colon. An empty value
empty value means allow all protocols. The valid protocol names, (see means allow all protocols. </p>
<b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" and "TLSv1". The
default value is "!SSLv2, !SSLv3" for Postfix releases after the
middle of 2015, "!SSLv2" for older releases. </p>
<p> With Postfix &ge; 2.5 the parameter syntax was expanded to support <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"SSLv3" set "<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below. </p>
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics.
</p>
<p> The range of protocols advertised by an SSL/TLS client must be <p> As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set a lowest acceptable TLS protocol version
higher version implicitly disables all versions above that higher version. and/or a highest acceptable TLS protocol version. To set the lower
Thus, for example (assuming the OpenSSL library supports both SSLv2 bound include an element of the form: "&gt;=<i>version</i>" where
and SSLv3): <i>version</i> is a either one of the TLS protocol names listed above,
</p> or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote> <blockquote>
<pre> <pre>
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !TLSv1 # Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=TLSv1.2, &lt;=0305
# Allow only TLS 1.2 and up:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=0x0303
</pre> </pre>
</blockquote> </blockquote>
<p> also disables any protocols version higher than TLSv1 leaving
only "SSLv3" enabled. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
and "TLSv1.2". When Postfix &le; 2.5 is linked against OpenSSL 1.0.1 version, and the protocol range is configured via protocol exclusions.
or later, these, or any other new protocol versions, cannot be To require at least TLS 1.0, set "<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2,
disabled except by also disabling "TLSv1" (typically leaving just !SSLv3". Listing the protocols to include, rather than protocols to
"SSLv3"). The latest patch levels of Postfix &ge; 2.6, and all exclude, is supported, but not recommended. The exclusion syntax more
versions of Postfix &ge; 2.10 can explicitly disable support for accurately matches the underlying OpenSSL interface. </p>
"TLSv1.1" or "TLSv1.2". </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> When using the exclusion syntax, take care to ensure that the range
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) of protocols supported by the Postfixm SMTP client is contiguous. When
this can be disabled, if need be, via "!TLSv1.3". </p> a protocol version is enabled, disabling any higher version implicitly
disables all versions above that higher version. Thus, for example: </p>
<p> At the <a href="TLS_README.html#client_tls_dane">dane</a> and <blockquote>
<a href="TLS_README.html#client_tls_dane">dane-only</a> security <pre>
levels, when usable TLSA records are obtained for the remote SMTP <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3, !TLSv1.1
server, the Postfix SMTP client is obligated to include the SNI TLS </pre>
extension in its SSL client hello message. This may help the remote </blockquote>
SMTP server live up to its promise to provide a certificate that
matches its TLSA records. Since TLS extensions require TLS 1.0 or <p> also disables any protocols version higher than TLSv1.1 leaving
later, the Postfix SMTP client must disable "SSLv2" and "SSLv3" when only "TLSv1" enabled. </p>
SNI is required. If you use "dane" or "dane-only" do not disable
TLSv1, except perhaps via the policy table for destinations which <p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
you are sure will support "TLSv1.1" or "TLSv1.2". </p> this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> While the vast majority of SMTP servers with DANE TLSA records now
support at least TLS 1.2, a few still only support TLS 1.0. If you use
"dane" or "dane-only" it is best to not disable TLSv1, except perhaps
via the policy table for destinations which you are sure will support
"TLSv1.2". </p>
<p> See the documentation of the <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> parameter and <p> See the documentation of the <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> parameter and
<a href="TLS_README.html">TLS_README</a> for more information about security levels. </p> <a href="TLS_README.html">TLS_README</a> for more information about security levels. </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=TLSv1.2, &lt;=TLSv1.3
# Legacy syntax: # Legacy syntax:
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = TLSv1 <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -13240,54 +13258,81 @@ configurations in environments where DNS security is not assured. </p>
</DD> </DD>
<DT><b><a name="smtp_tls_protocols">smtp_tls_protocols</a> <DT><b><a name="smtp_tls_protocols">smtp_tls_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see postconf -d output)</b></DT><DD>
<p> List of TLS protocols that the Postfix SMTP client will exclude or <p> TLS protocols that the Postfix SMTP client will use with
include with opportunistic TLS encryption. The default value is opportunistic TLS encryption. In <a href="postconf.5.html">main.cf</a> the values are separated by
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, whitespace, commas or colons. In the policy table "protocols" attribute
"!SSLv2" for older releases. Before Postfix 2.6, the Postfix SMTP (see <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid separator is colon. An empty
client would use all protocols with opportunistic TLS. </p> value means allow all protocols. </p>
<p> In <a href="postconf.5.html">main.cf</a> the values are separated by whitespace, commas or <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
colons. In the policy table (see <a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a>) the only valid "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
separator is colon. An empty value means allow all protocols. The valid Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
protocol names, (see <b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" the lowest supported TLS protocol version (see below). Older releases
and "TLSv1". </p> use the "!" exclusion syntax, also described below. </p>
<p> The range of protocols advertised by an SSL/TLS client must be <p> As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set the lowest acceptable TLS protocol
higher version implicitly disables all versions above that higher version. version and/or the highest acceptable TLS protocol version. To set the
Thus, for example (assuming the OpenSSL library supports both SSLv2 lower bound include an element of the form: "&gt;=<i>version</i>" where
and SSLv3): <i>version</i> is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = &gt;=TLSv1, &lt;=0305
# Allow only TLS 1.0 and up:
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = &gt;=0x0301
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3".
Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface. </p>
<p> When using the exclusion syntax, take care to ensure that the range of
protocols advertised by an SSL/TLS client is contiguous. When a protocol
version is enabled, disabling any higher version implicitly disables all
versions above that higher version. Thus, for example:
</p> </p>
<blockquote> <blockquote>
<pre> <pre>
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !TLSv1 <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3, !TLSv1.1
</pre> </pre>
</blockquote> </blockquote>
<p> also disables any protocols version higher than TLSv1 leaving <p> also disables any protocols version higher than TLSv1.1 leaving
only "SSLv3" enabled. </p> only "TLSv1" enabled. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
and "TLSv1.2". The latest patch levels of Postfix &ge; 2.6, and all this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
versions of Postfix &ge; 2.10 can explicitly disable support for releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
"TLSv1.1" or "TLSv1.2"</p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2)
this can be disabled, if need be, via "!TLSv1.3". </p>
<p> To include a protocol list its name, to exclude it, prefix the name
with a "!" character. To exclude SSLv2 for opportunistic TLS set
"<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2". To exclude both "SSLv2" and "SSLv3" set
"<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3". Explicitly listing the protocols to
include, rather than protocols to exclude, is supported, but not
recommended. The exclusion form more closely matches the underlying
OpenSSL interface semantics. </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# TLSv1 or better: # Preferred syntax with Postfix &ge; 3.6:
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = &gt;=TLSv1, &lt;=TLSv1.3
# Legacy syntax:
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3
</pre> </pre>
@ -13479,12 +13524,13 @@ Examples:
<pre> <pre>
# Opportunistic TLS. # Opportunistic TLS.
<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = may <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = may
# Postfix &ge; 2.6:
# Do not tweak opportunistic ciphers or protocol unless it is essential # Do not tweak opportunistic ciphers or protocol unless it is essential
# to do so (if a security vulnerability is found in the SSL library that # to do so (if a security vulnerability is found in the SSL library that
# can be mitigated by disabling a particular protocol or raising the # can be mitigated by disabling a particular protocol or raising the
# cipher grade from "export" to "low" or "medium"). # cipher grade).
<a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = export <a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> = medium
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = &gt;=TLSv1
# Legacy (Postfix &lt; 3.6) syntax:
<a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> = !SSLv2, !SSLv3
</pre> </pre>
@ -13495,33 +13541,27 @@ Examples:
</pre> </pre>
<pre> <pre>
# Mandatory TLS verification of hostname or nexthop domain. # Authenticated TLS 1.2 or better matching the nexthop domain or a
<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = verify # subdomain.
<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high
<a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> = hostname, nexthop, dot-nexthop
</pre>
<pre>
# Secure channel TLS with exact nexthop name match.
<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = secure <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = secure
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = TLSv1
<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high
<a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> = nexthop <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=TLSv1.2
<a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> = nexthop, dot-nexthop
</pre> </pre>
<pre> <pre>
# Certificate fingerprint verification (Postfix &ge; 2.5). # Certificate fingerprint verification (Postfix &ge; 2.5).
# The CA-less "fingerprint" security level only scales to a limited # The CA-less "fingerprint" security level only scales to a limited
# number of destinations. As a global default rather than a per-site # number of destinations. As a global default rather than a per-site
# setting, this is practical when mail for all recipients is sent # setting, this is practical only when mail for all recipients is sent
# to a central mail hub. # to a central mail hub.
<a href="postconf.5.html#relayhost">relayhost</a> = [mailhub.example.com] <a href="postconf.5.html#relayhost">relayhost</a> = [mailhub.example.com]
<a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = fingerprint <a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> = fingerprint
<a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> = &gt;=TLSv1.2
<a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high <a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> = high
<a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> = <a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> =
3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 3D:95:34:51:...:40:99:C0:C1
EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 EC:3B:2D:B0:...:A3:9D:72:F6
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -17639,43 +17679,69 @@ works in addition to the exclusions listed with <a href="postconf.5.html#smtpd_t
</DD> </DD>
<DT><b><a name="smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> <DT><b><a name="smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see "postconf -d" output)</b></DT><DD>
<p> The SSL/TLS protocols accepted by the Postfix SMTP server with <p> TLS protocols accepted by the Postfix SMTP server with mandatory TLS
mandatory TLS encryption. If the list is empty, the server supports encryption. If the list is empty, the server supports all available TLS
all available SSL/TLS protocol versions. A non-empty value is a protocol versions. A non-empty value is a list of protocol names to
list of protocol names separated by whitespace, commas or colons. include or exclude, separated by whitespace, commas or colons. </p>
The supported protocol names are "SSLv2", "SSLv3" and "TLSv1", and
are not case sensitive. The default value is "!SSLv2, !SSLv3" for
Postfix releases after the middle of 2015, "!SSLv2" for older
releases. </p>
<p> With Postfix &ge; 2.5 the parameter syntax was expanded to support <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"SSLv3" set "<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below. </p>
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> As of Postfix 3.6, the preferred way to limit the range of
and "TLSv1.2". When Postfix &le; 2.5 is linked against OpenSSL 1.0.1 acceptable protocols is to set the lowest acceptable TLS protocol
or later, these, or any other new protocol versions, cannot be version and/or the highest acceptable TLS protocol version. To set the
disabled. The latest patch levels of Postfix &ge; 2.6, and all lower bound include an element of the form: "&gt;=<i>version</i>" where
versions of Postfix &ge; 2.10 can disable support for "TLSv1.1" or <i>version</i> is a either one of the TLS protocol names listed above,
"TLSv1.2". </p> or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> Hexadecimal protocol numbers make it possible to specify protocol
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) bounds for TLS versions that are known to OpenSSL, but might not be
this can be disabled, if need be, via "!TLSv1.3". </p> known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = &gt;=TLSv1.2, &lt;=0305
# Allow only TLS 1.2 and up:
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = &gt;=0x0303
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> =
!SSLv2, !SSLv3". Listing the protocols to include, rather than
protocols to exclude, is supported, but not recommended. The exclusion
form more accurately matches the underlying OpenSSL interface. </p>
<p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = &gt;=TLSv1.2, &lt;=TLSv1.3
# Legacy syntax: # Legacy syntax:
<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = TLSv1 <a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -17684,36 +17750,67 @@ this can be disabled, if need be, via "!TLSv1.3". </p>
</DD> </DD>
<DT><b><a name="smtpd_tls_protocols">smtpd_tls_protocols</a> <DT><b><a name="smtpd_tls_protocols">smtpd_tls_protocols</a>
(default: !SSLv2, !SSLv3)</b></DT><DD> (default: see postconf -d output)</b></DT><DD>
<p> List of TLS protocols that the Postfix SMTP server will exclude <p> TLS protocols accepted by the Postfix SMTP server with opportunistic
or include with opportunistic TLS encryption. The default value is TLS encryption. If the list is empty, the server supports all available
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, TLS protocol versions. A non-empty value is a list of protocol names to
empty for older releases allowing all protocols to be include or exclude, separated by whitespace, commas or colons. </p>
used with opportunistic TLS. A non-empty value is a list of protocol
names separated by whitespace, commas or colons. The supported
protocol names are "SSLv2", "SSLv3" and "TLSv1", and are not case
sensitive. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
and "TLSv1.2". The latest patch levels of Postfix &ge; 2.6, and all "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
versions of Postfix &ge; 2.10 can disable support for "TLSv1.1" or Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"TLSv1.2". </p> the lowest supported TLS protocol version (see below). Older releases
use the "!" exclusion syntax, also described below. </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> As of Postfix 3.6, the preferred way to limit the range of
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) acceptable protocols is to set the lowest acceptable TLS protocol
this can be disabled, if need be, via "!TLSv1.3". </p> version and/or the highest acceptable TLS protocol version. To set the
lower bound include an element of the form: "&gt;=<i>version</i>" where
<i>version</i> is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> To include a protocol list its name, to exclude it, prefix the name <p> Hexadecimal protocol numbers make it possible to specify protocol
with a "!" character. To exclude SSLv2 for opportunistic TLS set bounds for TLS versions that are known to OpenSSL, but might not be
"<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2". To exclude both "SSLv2" and "SSLv3" set known to Postfix. They cannot be used with the legacy exclusion syntax.
"<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2, !SSLv3". Explicitly listing the protocols to Leading "0" or "0x" prefixes are supported, but not required.
include, rather than protocols to exclude, is supported, but not Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
recommended. The exclusion form more closely matches the underlying "TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
OpenSSL interface semantics. </p> upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = &gt;=TLSv1, &lt;=0305
# Allow only TLS 1.0 and up:
<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = &gt;=0x0301
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2, !SSLv3".
Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface. </p>
<p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 3.6:
<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = &gt;=TLSv1, &lt;=TLSv1.3
# Legacy syntax:
<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2, !SSLv3 <a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> = !SSLv2, !SSLv3
</pre> </pre>

40
postfix/html/posttls-finger.1.html
View File

@ -4,7 +4,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<title> Postfix manual - posttls-finger(1) </title> <title> Postfix manual - posttls-finger(1) </title>
</head> <body> <pre> </head> <body> <pre>
POSTTLS-FINGER(1) General Commands Manual POSTTLS-FINGER(1) POSTTLS-FINGER(1) POSTTLS-FINGER(1)
<b>NAME</b> <b>NAME</b>
posttls-finger - Probe the TLS properties of an ESMTP or LMTP server. posttls-finger - Probe the TLS properties of an ESMTP or LMTP server.
@ -255,9 +255,9 @@ POSTTLS-FINGER(1) General Commands Manual POSTTLS-FINGER(1)
ing the values of TLS library parameters, or "<a href="postconf.5.html#myhostname">myhostname</a>" to ing the values of TLS library parameters, or "<a href="postconf.5.html#myhostname">myhostname</a>" to
configure the SMTP EHLO name sent to the remote server. configure the SMTP EHLO name sent to the remote server.
<b>-p</b> <i>protocols</i> (default: !SSLv2) <b>-p</b> <i>protocols</i> (default: &gt;=TLSv1)
List of TLS protocols that posttls-finger will exclude or TLS protocols that posttls-finger will exclude or include. See
include. See <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> for details. <a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> for details.
<b>-P</b> <i>CApath/</i> (default: none) <b>-P</b> <i>CApath/</i> (default: none)
The OpenSSL CApath/ directory (indexed via c_rehash(1)) for The OpenSSL CApath/ directory (indexed via c_rehash(1)) for
@ -288,31 +288,31 @@ POSTTLS-FINGER(1) General Commands Manual POSTTLS-FINGER(1)
reading the remote server's 220 banner. reading the remote server's 220 banner.
<b>-T</b> <i>timeout</i> (default: <b>30</b>) <b>-T</b> <i>timeout</i> (default: <b>30</b>)
The SMTP/LMTP command timeout for EHLO/LHLO, STARTTLS and QUIT. The SMTP/LMTP command timeout for EHLO/LHLO, STARTTLS and QUIT.
<b>-v</b> Enable verbose Postfix logging. Specify more than once to <b>-v</b> Enable verbose Postfix logging. Specify more than once to
increase the level of verbose logging. increase the level of verbose logging.
<b>-w</b> Enable outgoing TLS wrapper mode, or SMTPS support. This is <b>-w</b> Enable outgoing TLS wrapper mode, or SMTPS support. This is
typically provided on port 465 by servers that are compatible typically provided on port 465 by servers that are compatible
with the ad-hoc SMTP in SSL protocol, rather than the standard with the ad-hoc SMTP in SSL protocol, rather than the standard
STARTTLS protocol. The destination <i>domain</i>:<i>port</i> should of course STARTTLS protocol. The destination <i>domain</i>:<i>port</i> should of course
provide such a service. provide such a service.
<b>-X</b> Enable <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> mode. This is an unsupported mode, for pro- <b>-X</b> Enable <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> mode. This is an unsupported mode, for pro-
gram development only. gram development only.
[<b>inet:</b>]<i>domain</i>[:<i>port</i>] [<b>inet:</b>]<i>domain</i>[:<i>port</i>]
Connect via TCP to domain <i>domain</i>, port <i>port</i>. The default port is Connect via TCP to domain <i>domain</i>, port <i>port</i>. The default port is
<b>smtp</b> (or 24 with LMTP). With SMTP an MX lookup is performed to <b>smtp</b> (or 24 with LMTP). With SMTP an MX lookup is performed to
resolve the domain to a host, unless the domain is enclosed in resolve the domain to a host, unless the domain is enclosed in
<b>[]</b>. If you want to connect to a specific MX host, for instance <b>[]</b>. If you want to connect to a specific MX host, for instance
<i>mx1.example.com</i>, specify [<i>mx1.example.com</i>] as the destination <i>mx1.example.com</i>, specify [<i>mx1.example.com</i>] as the destination
and <i>example.com</i> as a <b>match</b> argument. When using DNS, the desti- and <i>example.com</i> as a <b>match</b> argument. When using DNS, the desti-
nation domain is assumed fully qualified and no default domain nation domain is assumed fully qualified and no <a href="ADDRESS_CLASS_README.html#default_domain_class">default domain</a>
or search suffixes are applied; you must use fully-qualified or search suffixes are applied; you must use fully-qualified
names or also enable <b>native</b> host lookups (these don't support names or also enable <b>native</b> host lookups (these don't support
<b>dane</b> or <b>dane-only</b> as no DNSSEC validation information is avail- <b>dane</b> or <b>dane-only</b> as no DNSSEC validation information is avail-
able via <b>native</b> lookups). able via <b>native</b> lookups).
<b>unix:</b><i>pathname</i> <b>unix:</b><i>pathname</i>
@ -321,8 +321,8 @@ POSTTLS-FINGER(1) General Commands Manual POSTTLS-FINGER(1)
<b>match ...</b> <b>match ...</b>
With no match arguments specified, certificate peername matching With no match arguments specified, certificate peername matching
uses the compiled-in default strategies for each security level. uses the compiled-in default strategies for each security level.
If you specify one or more arguments, these will be used as the If you specify one or more arguments, these will be used as the
list of certificate or public-key digests to match for the <b>fin-</b> list of certificate or public-key digests to match for the <b>fin-</b>
<b>gerprint</b> level, or as the list of DNS names to match in the cer- <b>gerprint</b> level, or as the list of DNS names to match in the cer-
tificate at the <b>verify</b> and <b>secure</b> levels. If the security level tificate at the <b>verify</b> and <b>secure</b> levels. If the security level
is <b>dane</b>, or <b>dane-only</b> the match names are ignored, and <b>hostname,</b> is <b>dane</b>, or <b>dane-only</b> the match names are ignored, and <b>hostname,</b>

12
postfix/html/smtp.8.html
View File

@ -508,9 +508,9 @@ SMTP(8) SMTP(8)
policy by next-hop destination; when a non-empty value is speci- policy by next-hop destination; when a non-empty value is speci-
fied, this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter. fied, this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter.
<b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (see 'postconf -d' output)</b>
List of SSL/TLS protocols that the Postfix SMTP client will use TLS protocols that the Postfix SMTP client will use with manda-
with mandatory TLS encryption. tory TLS encryption.
<b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b> <b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b>
The verification depth for remote SMTP server certificates. The verification depth for remote SMTP server certificates.
@ -573,9 +573,9 @@ SMTP(8) SMTP(8)
Available in Postfix version 2.6 and later: Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (see postconf -d output)</b>
List of TLS protocols that the Postfix SMTP client will exclude TLS protocols that the Postfix SMTP client will use with oppor-
or include with opportunistic TLS encryption. tunistic TLS encryption.
<b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (medium)</b> <b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (medium)</b>
The minimum TLS cipher grade that the Postfix SMTP client will The minimum TLS cipher grade that the Postfix SMTP client will

12
postfix/html/smtpd.8.html
View File

@ -475,9 +475,9 @@ SMTPD(8) SMTPD(8)
Postfix SMTP server cipher list at mandatory TLS security lev- Postfix SMTP server cipher list at mandatory TLS security lev-
els. els.
<b><a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_mandatory_protocols</a> (see 'postconf -d' output)</b>
The SSL/TLS protocols accepted by the Postfix SMTP server with TLS protocols accepted by the Postfix SMTP server with mandatory
mandatory TLS encryption. TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_received_header">smtpd_tls_received_header</a> (no)</b> <b><a href="postconf.5.html#smtpd_tls_received_header">smtpd_tls_received_header</a> (no)</b>
Request that the Postfix SMTP server produces Received: message Request that the Postfix SMTP server produces Received: message
@ -524,9 +524,9 @@ SMTPD(8) SMTPD(8)
Available in Postfix version 2.6 and later: Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> (!SSLv2, !SSLv3)</b> <b><a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a> (see postconf -d output)</b>
List of TLS protocols that the Postfix SMTP server will exclude TLS protocols accepted by the Postfix SMTP server with oppor-
or include with opportunistic TLS encryption. tunistic TLS encryption.
<b><a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> (medium)</b> <b><a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a> (medium)</b>
The minimum TLS cipher grade that the Postfix SMTP server will The minimum TLS cipher grade that the Postfix SMTP server will

4
postfix/man/man1/posttls-finger.1
View File

@ -230,8 +230,8 @@ Specify zero or more times to override the value of the main.cf
parameter \fIname\fR with \fIvalue\fR. Possible use\-cases include parameter \fIname\fR with \fIvalue\fR. Possible use\-cases include
overriding the values of TLS library parameters, or "myhostname" to overriding the values of TLS library parameters, or "myhostname" to
configure the SMTP EHLO name sent to the remote server. configure the SMTP EHLO name sent to the remote server.
.IP "\fB\-p \fIprotocols\fR (default: !SSLv2)" .IP "\fB\-p \fIprotocols\fR (default: >=TLSv1)"
List of TLS protocols that posttls\-finger will exclude or include. See TLS protocols that posttls\-finger will exclude or include. See
smtp_tls_mandatory_protocols for details. smtp_tls_mandatory_protocols for details.
.IP "\fB\-P \fICApath/\fR (default: none)" .IP "\fB\-P \fICApath/\fR (default: none)"
The OpenSSL CApath/ directory (indexed via c_rehash(1)) for remote The OpenSSL CApath/ directory (indexed via c_rehash(1)) for remote

466
postfix/man/man5/postconf.5
View File

@ -3242,7 +3242,7 @@ The LMTP\-specific version of the smtp_tls_mandatory_exclude_ciphers
configuration parameter. See there for details. configuration parameter. See there for details.
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH lmtp_tls_mandatory_protocols (default: !SSLv2, !SSLv3) .SH lmtp_tls_mandatory_protocols (default: see postconf \-d output)
The LMTP\-specific version of the smtp_tls_mandatory_protocols The LMTP\-specific version of the smtp_tls_mandatory_protocols
configuration parameter. See there for details. configuration parameter. See there for details.
.PP .PP
@ -3262,7 +3262,7 @@ The LMTP\-specific version of the smtp_tls_policy_maps
configuration parameter. See there for details. configuration parameter. See there for details.
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH lmtp_tls_protocols (default: !SSLv2, !SSLv3) .SH lmtp_tls_protocols (default: see postconf \-d output)
The LMTP\-specific version of the smtp_tls_protocols configuration The LMTP\-specific version of the smtp_tls_protocols configuration
parameter. See there for details. parameter. See there for details.
.PP .PP
@ -8373,78 +8373,102 @@ specified on a per\-destination basis via the TLS policy "exclude"
attribute. See smtp_tls_policy_maps for notes and examples. attribute. See smtp_tls_policy_maps for notes and examples.
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH smtp_tls_mandatory_protocols (default: !SSLv2, !SSLv3) .SH smtp_tls_mandatory_protocols (default: see "postconf \-d" output)
List of SSL/TLS protocols that the Postfix SMTP client will use with TLS protocols that the Postfix SMTP client will use with mandatory
mandatory TLS encryption. In main.cf the values are separated by TLS encryption. In main.cf the values are separated by whitespace,
whitespace, commas or colons. In the policy table "protocols" attribute commas or colons. In the policy table "protocols" attribute (see
(see smtp_tls_policy_maps) the only valid separator is colon. An smtp_tls_policy_maps) the only valid separator is colon. An empty value
empty value means allow all protocols. The valid protocol names, (see means allow all protocols.
\\fBfBSSL_get_version\fR(3)\fR), are "SSLv2", "SSLv3" and "TLSv1". The
default value is "!SSLv2, !SSLv3" for Postfix releases after the
middle of 2015, "!SSLv2" for older releases.
.PP .PP
With Postfix >= 2.5 the parameter syntax was expanded to support The valid protocol names (see \fBSSL_get_version\fR(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"smtp_tls_mandatory_protocols = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is ">=TLSv1", which sets TLS 1.0 as
"SSLv3" set "smtp_tls_mandatory_protocols = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below.
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics.
.PP .PP
The range of protocols advertised by an SSL/TLS client must be As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set a lowest acceptable TLS protocol version
higher version implicitly disables all versions above that higher version. and/or a highest acceptable TLS protocol version. To set the lower
Thus, for example (assuming the OpenSSL library supports both SSLv2 bound include an element of the form: ">=\fIversion\fR" where
and SSLv3): \fIversion\fR is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "<=\fIversion\fR". There must be no whitespace between
the ">=" or "<=" symbols and the protocol name or number.
.PP
Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version.
.PP
Hexadecimal example (Postfix >= 3.6):
.sp .sp
.in +4 .in +4
.nf .nf
.na .na
.ft C .ft C
smtp_tls_mandatory_protocols = !SSLv2, !TLSv1 # Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtp_tls_mandatory_protocols = >=TLSv1.2, <=0305
# Allow only TLS 1.2 and up:
smtp_tls_mandatory_protocols = >=0x0303
.fi .fi
.ad .ad
.ft R .ft R
.in -4 .in -4
also disables any protocols version higher than TLSv1 leaving
only "SSLv3" enabled.
.PP .PP
Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" With Postfix < 3.6 there is no support for a minimum or maximum
and "TLSv1.2". When Postfix <= 2.5 is linked against OpenSSL 1.0.1 version, and the protocol range is configured via protocol exclusions.
or later, these, or any other new protocol versions, cannot be To require at least TLS 1.0, set "smtp_tls_mandatory_protocols = !SSLv2,
disabled except by also disabling "TLSv1" (typically leaving just !SSLv3". Listing the protocols to include, rather than protocols to
"SSLv3"). The latest patch levels of Postfix >= 2.6, and all exclude, is supported, but not recommended. The exclusion syntax more
versions of Postfix >= 2.10 can explicitly disable support for accurately matches the underlying OpenSSL interface.
"TLSv1.1" or "TLSv1.2".
.PP .PP
OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix When using the exclusion syntax, take care to ensure that the range
>= 3.4 (or patch releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2) of protocols supported by the Postfixm SMTP client is contiguous. When
this can be disabled, if need be, via "!TLSv1.3". a protocol version is enabled, disabling any higher version implicitly
disables all versions above that higher version. Thus, for example:
.sp
.in +4
.nf
.na
.ft C
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1.1
.fi
.ad
.ft R
.in -4
.PP .PP
At the dane and also disables any protocols version higher than TLSv1.1 leaving
dane\-only security only "TLSv1" enabled.
levels, when usable TLSA records are obtained for the remote SMTP .PP
server, the Postfix SMTP client is obligated to include the SNI TLS Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
extension in its SSL client hello message. This may help the remote this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
SMTP server live up to its promise to provide a certificate that releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2).
matches its TLSA records. Since TLS extensions require TLS 1.0 or .PP
later, the Postfix SMTP client must disable "SSLv2" and "SSLv3" when While the vast majority of SMTP servers with DANE TLSA records now
SNI is required. If you use "dane" or "dane\-only" do not disable support at least TLS 1.2, a few still only support TLS 1.0. If you use
TLSv1, except perhaps via the policy table for destinations which "dane" or "dane\-only" it is best to not disable TLSv1, except perhaps
you are sure will support "TLSv1.1" or "TLSv1.2". via the policy table for destinations which you are sure will support
"TLSv1.2".
.PP .PP
See the documentation of the smtp_tls_policy_maps parameter and See the documentation of the smtp_tls_policy_maps parameter and
TLS_README for more information about security levels. TLS_README for more information about security levels.
.PP .PP
Example: Example:
.PP
.nf .nf
.na .na
.ft C .ft C
# Preferred syntax with Postfix >= 2.5: # Preferred syntax with Postfix >= 3.6:
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_protocols = >=TLSv1.2, <=TLSv1.3
# Legacy syntax: # Legacy syntax:
smtp_tls_mandatory_protocols = TLSv1 smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
.fi .fi
.ad .ad
.ft R .ft R
@ -8716,59 +8740,91 @@ DNS forgery. Do not use the \fBhostname\fR strategy for secure\-channel
configurations in environments where DNS security is not assured. configurations in environments where DNS security is not assured.
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH smtp_tls_protocols (default: !SSLv2, !SSLv3) .SH smtp_tls_protocols (default: see postconf \-d output)
List of TLS protocols that the Postfix SMTP client will exclude or TLS protocols that the Postfix SMTP client will use with
include with opportunistic TLS encryption. The default value is opportunistic TLS encryption. In main.cf the values are separated by
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, whitespace, commas or colons. In the policy table "protocols" attribute
"!SSLv2" for older releases. Before Postfix 2.6, the Postfix SMTP (see smtp_tls_policy_maps) the only valid separator is colon. An empty
client would use all protocols with opportunistic TLS. value means allow all protocols.
.PP .PP
In main.cf the values are separated by whitespace, commas or The valid protocol names (see \fBSSL_get_version\fR(3)) are "SSLv2",
colons. In the policy table (see smtp_tls_policy_maps) the only valid "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
separator is colon. An empty value means allow all protocols. The valid Postfix 3.6, the default value is ">=TLSv1", which sets TLS 1.0 as
protocol names, (see \\fBfBSSL_get_version\fR(3)\fR), are "SSLv2", "SSLv3" the lowest supported TLS protocol version (see below). Older releases
and "TLSv1". use the "!" exclusion syntax, also described below.
.PP .PP
The range of protocols advertised by an SSL/TLS client must be As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set the lowest acceptable TLS protocol
higher version implicitly disables all versions above that higher version. version and/or the highest acceptable TLS protocol version. To set the
Thus, for example (assuming the OpenSSL library supports both SSLv2 lower bound include an element of the form: ">=\fIversion\fR" where
and SSLv3): \fIversion\fR is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "<=\fIversion\fR". There must be no whitespace between
the ">=" or "<=" symbols and the protocol name or number.
.PP
Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version.
.PP
Hexadecimal example (Postfix >= 3.6):
.sp .sp
.in +4 .in +4
.nf .nf
.na .na
.ft C .ft C
smtp_tls_protocols = !SSLv2, !TLSv1 # Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtp_tls_protocols = >=TLSv1, <=0305
# Allow only TLS 1.0 and up:
smtp_tls_protocols = >=0x0301
.fi .fi
.ad .ad
.ft R .ft R
.in -4 .in -4
also disables any protocols version higher than TLSv1 leaving
only "SSLv3" enabled.
.PP .PP
Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" With Postfix < 3.6 there is no support for a minimum or maximum
and "TLSv1.2". The latest patch levels of Postfix >= 2.6, and all version, and the protocol range is configured via protocol exclusions.
versions of Postfix >= 2.10 can explicitly disable support for To require at least TLS 1.0, set "smtp_tls_protocols = !SSLv2, !SSLv3".
"TLSv1.1" or "TLSv1.2" Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface.
.PP .PP
OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix When using the exclusion syntax, take care to ensure that the range of
>= 3.4 (or patch releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2) protocols advertised by an SSL/TLS client is contiguous. When a protocol
this can be disabled, if need be, via "!TLSv1.3". version is enabled, disabling any higher version implicitly disables all
versions above that higher version. Thus, for example:
.sp
.in +4
.nf
.na
.ft C
smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1.1
.fi
.ad
.ft R
.in -4
also disables any protocols version higher than TLSv1.1 leaving
only "TLSv1" enabled.
.PP .PP
To include a protocol list its name, to exclude it, prefix the name Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
with a "!" character. To exclude SSLv2 for opportunistic TLS set this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
"smtp_tls_protocols = !SSLv2". To exclude both "SSLv2" and "SSLv3" set releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2).
"smtp_tls_protocols = !SSLv2, !SSLv3". Explicitly listing the protocols to
include, rather than protocols to exclude, is supported, but not
recommended. The exclusion form more closely matches the underlying
OpenSSL interface semantics.
.PP .PP
Example: Example:
.nf .nf
.na .na
.ft C .ft C
# TLSv1 or better: # Preferred syntax with Postfix >= 3.6:
smtp_tls_protocols = >=TLSv1, <=TLSv1.3
# Legacy syntax:
smtp_tls_protocols = !SSLv2, !SSLv3 smtp_tls_protocols = !SSLv2, !SSLv3
.fi .fi
.ad .ad
@ -8947,12 +9003,13 @@ smtp_tls_security_level = none
.ft C .ft C
# Opportunistic TLS. # Opportunistic TLS.
smtp_tls_security_level = may smtp_tls_security_level = may
# Postfix >= 2.6:
# Do not tweak opportunistic ciphers or protocol unless it is essential # Do not tweak opportunistic ciphers or protocol unless it is essential
# to do so (if a security vulnerability is found in the SSL library that # to do so (if a security vulnerability is found in the SSL library that
# can be mitigated by disabling a particular protocol or raising the # can be mitigated by disabling a particular protocol or raising the
# cipher grade from "export" to "low" or "medium"). # cipher grade).
smtp_tls_ciphers = export smtp_tls_ciphers = medium
smtp_tls_protocols = >=TLSv1
# Legacy (Postfix < 3.6) syntax:
smtp_tls_protocols = !SSLv2, !SSLv3 smtp_tls_protocols = !SSLv2, !SSLv3
.fi .fi
.ad .ad
@ -8971,22 +9028,12 @@ smtp_tls_mandatory_ciphers = high
.nf .nf
.na .na
.ft C .ft C
# Mandatory TLS verification of hostname or nexthop domain. # Authenticated TLS 1.2 or better matching the nexthop domain or a
smtp_tls_security_level = verify # subdomain.
smtp_tls_mandatory_ciphers = high
smtp_tls_verify_cert_match = hostname, nexthop, dot\-nexthop
.fi
.ad
.ft R
.PP
.nf
.na
.ft C
# Secure channel TLS with exact nexthop name match.
smtp_tls_security_level = secure smtp_tls_security_level = secure
smtp_tls_mandatory_protocols = TLSv1
smtp_tls_mandatory_ciphers = high smtp_tls_mandatory_ciphers = high
smtp_tls_secure_cert_match = nexthop smtp_tls_mandatory_protocols = >=TLSv1.2
smtp_tls_secure_cert_match = nexthop, dot\-nexthop
.fi .fi
.ad .ad
.ft R .ft R
@ -8997,15 +9044,15 @@ smtp_tls_secure_cert_match = nexthop
# Certificate fingerprint verification (Postfix >= 2.5). # Certificate fingerprint verification (Postfix >= 2.5).
# The CA\-less "fingerprint" security level only scales to a limited # The CA\-less "fingerprint" security level only scales to a limited
# number of destinations. As a global default rather than a per\-site # number of destinations. As a global default rather than a per\-site
# setting, this is practical when mail for all recipients is sent # setting, this is practical only when mail for all recipients is sent
# to a central mail hub. # to a central mail hub.
relayhost = [mailhub.example.com] relayhost = [mailhub.example.com]
smtp_tls_security_level = fingerprint smtp_tls_security_level = fingerprint
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_protocols = >=TLSv1.2
smtp_tls_mandatory_ciphers = high smtp_tls_mandatory_ciphers = high
smtp_tls_fingerprint_cert_match = smtp_tls_fingerprint_cert_match =
3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 3D:95:34:51:...:40:99:C0:C1
EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 EC:3B:2D:B0:...:A3:9D:72:F6
.fi .fi
.ad .ad
.ft R .ft R
@ -12280,80 +12327,147 @@ works in addition to the exclusions listed with smtpd_tls_exclude_ciphers
(see there for syntax details). (see there for syntax details).
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH smtpd_tls_mandatory_protocols (default: !SSLv2, !SSLv3) .SH smtpd_tls_mandatory_protocols (default: see "postconf \-d" output)
The SSL/TLS protocols accepted by the Postfix SMTP server with TLS protocols accepted by the Postfix SMTP server with mandatory TLS
mandatory TLS encryption. If the list is empty, the server supports encryption. If the list is empty, the server supports all available TLS
all available SSL/TLS protocol versions. A non\-empty value is a protocol versions. A non\-empty value is a list of protocol names to
list of protocol names separated by whitespace, commas or colons. include or exclude, separated by whitespace, commas or colons.
The supported protocol names are "SSLv2", "SSLv3" and "TLSv1", and
are not case sensitive. The default value is "!SSLv2, !SSLv3" for
Postfix releases after the middle of 2015, "!SSLv2" for older
releases.
.PP .PP
With Postfix >= 2.5 the parameter syntax was expanded to support The valid protocol names (see \fBSSL_get_version\fR(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"smtpd_tls_mandatory_protocols = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is ">=TLSv1", which sets TLS 1.0 as
"SSLv3" set "smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below.
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics.
.PP .PP
Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" As of Postfix 3.6, the preferred way to limit the range of
and "TLSv1.2". When Postfix <= 2.5 is linked against OpenSSL 1.0.1 acceptable protocols is to set the lowest acceptable TLS protocol
or later, these, or any other new protocol versions, cannot be version and/or the highest acceptable TLS protocol version. To set the
disabled. The latest patch levels of Postfix >= 2.6, and all lower bound include an element of the form: ">=\fIversion\fR" where
versions of Postfix >= 2.10 can disable support for "TLSv1.1" or \fIversion\fR is a either one of the TLS protocol names listed above,
"TLSv1.2". or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "<=\fIversion\fR". There must be no whitespace between
the ">=" or "<=" symbols and the protocol name or number.
.PP .PP
OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix Hexadecimal protocol numbers make it possible to specify protocol
>= 3.4 (or patch releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2) bounds for TLS versions that are known to OpenSSL, but might not be
this can be disabled, if need be, via "!TLSv1.3". known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version.
.PP
Hexadecimal example (Postfix >= 3.6):
.sp
.in +4
.nf
.na
.ft C
# Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtpd_tls_mandatory_protocols = >=TLSv1.2, <=0305
# Allow only TLS 1.2 and up:
smtpd_tls_mandatory_protocols = >=0x0303
.fi
.ad
.ft R
.in -4
.PP
With Postfix < 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "smtpd_tls_mandatory_protocols =
!SSLv2, !SSLv3". Listing the protocols to include, rather than
protocols to exclude, is supported, but not recommended. The exclusion
form more accurately matches the underlying OpenSSL interface.
.PP
Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2).
.PP .PP
Example: Example:
.PP .PP
.nf .nf
.na .na
.ft C .ft C
# Preferred syntax with Postfix >= 2.5: # Preferred syntax with Postfix >= 3.6:
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_mandatory_protocols = >=TLSv1.2, <=TLSv1.3
# Legacy syntax: # Legacy syntax:
smtpd_tls_mandatory_protocols = TLSv1 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
.fi .fi
.ad .ad
.ft R .ft R
.PP .PP
This feature is available in Postfix 2.3 and later. This feature is available in Postfix 2.3 and later.
.SH smtpd_tls_protocols (default: !SSLv2, !SSLv3) .SH smtpd_tls_protocols (default: see postconf \-d output)
List of TLS protocols that the Postfix SMTP server will exclude TLS protocols accepted by the Postfix SMTP server with opportunistic
or include with opportunistic TLS encryption. The default value is TLS encryption. If the list is empty, the server supports all available
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, TLS protocol versions. A non\-empty value is a list of protocol names to
empty for older releases allowing all protocols to be include or exclude, separated by whitespace, commas or colons.
used with opportunistic TLS. A non\-empty value is a list of protocol
names separated by whitespace, commas or colons. The supported
protocol names are "SSLv2", "SSLv3" and "TLSv1", and are not case
sensitive.
.PP .PP
Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" The valid protocol names (see \fBSSL_get_version\fR(3)) are "SSLv2",
and "TLSv1.2". The latest patch levels of Postfix >= 2.6, and all "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
versions of Postfix >= 2.10 can disable support for "TLSv1.1" or Postfix 3.6, the default value is ">=TLSv1", which sets TLS 1.0 as
"TLSv1.2". the lowest supported TLS protocol version (see below). Older releases
use the "!" exclusion syntax, also described below.
.PP .PP
OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix As of Postfix 3.6, the preferred way to limit the range of
>= 3.4 (or patch releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2) acceptable protocols is to set the lowest acceptable TLS protocol
this can be disabled, if need be, via "!TLSv1.3". version and/or the highest acceptable TLS protocol version. To set the
lower bound include an element of the form: ">=\fIversion\fR" where
\fIversion\fR is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "<=\fIversion\fR". There must be no whitespace between
the ">=" or "<=" symbols and the protocol name or number.
.PP .PP
To include a protocol list its name, to exclude it, prefix the name Hexadecimal protocol numbers make it possible to specify protocol
with a "!" character. To exclude SSLv2 for opportunistic TLS set bounds for TLS versions that are known to OpenSSL, but might not be
"smtpd_tls_protocols = !SSLv2". To exclude both "SSLv2" and "SSLv3" set known to Postfix. They cannot be used with the legacy exclusion syntax.
"smtpd_tls_protocols = !SSLv2, !SSLv3". Explicitly listing the protocols to Leading "0" or "0x" prefixes are supported, but not required.
include, rather than protocols to exclude, is supported, but not Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
recommended. The exclusion form more closely matches the underlying "TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
OpenSSL interface semantics. upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version.
.PP
Hexadecimal example (Postfix >= 3.6):
.sp
.in +4
.nf
.na
.ft C
# Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtpd_tls_protocols = >=TLSv1, <=0305
# Allow only TLS 1.0 and up:
smtpd_tls_protocols = >=0x0301
.fi
.ad
.ft R
.in -4
.PP
With Postfix < 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "smtpd_tls_protocols = !SSLv2, !SSLv3".
Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface.
.PP
Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases >= 3.0.14, 3.1.10, 3.2.7 and 3.3.2).
.PP .PP
Example: Example:
.nf .nf
.na .na
.ft C .ft C
# Preferred syntax with Postfix >= 3.6:
smtpd_tls_protocols = >=TLSv1, <=TLSv1.3
# Legacy syntax:
smtpd_tls_protocols = !SSLv2, !SSLv3 smtpd_tls_protocols = !SSLv2, !SSLv3
.fi .fi
.ad .ad
@ -12845,7 +12959,7 @@ bug work\-arounds to disable.
If the value of the parameter is a hexadecimal long integer starting If the value of the parameter is a hexadecimal long integer starting
with "0x", the bug work\-arounds corresponding to the bits specified in with "0x", the bug work\-arounds corresponding to the bits specified in
its value are removed from the \fBSSL_OP_ALL\fR work\-around bit\-mask its value are removed from the \fBSSL_OP_ALL\fR work\-around bit\-mask
(see openssl/ssl.h and SSL_CTX_\fBset_options\fR(3)). You can specify more (see openssl/ssl.h and \fBSSL_CTX_set_options\fR(3)). You can specify more
bits than are present in SSL_OP_ALL, excess bits are ignored. Specifying bits than are present in SSL_OP_ALL, excess bits are ignored. Specifying
0xFFFFFFFF disables all bug\-workarounds on a 32\-bit system. This should 0xFFFFFFFF disables all bug\-workarounds on a 32\-bit system. This should
also be sufficient on 64\-bit systems, until OpenSSL abandons support also be sufficient on 64\-bit systems, until OpenSSL abandons support
@ -12863,17 +12977,17 @@ OpenSSL 1.0.0.
.br .br
.IP "\fBDONT_INSERT_EMPTY_FRAGMENTS\fR" .IP "\fBDONT_INSERT_EMPTY_FRAGMENTS\fR"
See See
SSL_CTX_\fBset_options\fR(3) \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBLEGACY_SERVER_CONNECT\fR" .IP "\fBLEGACY_SERVER_CONNECT\fR"
See SSL_CTX_\fBset_options\fR(3) See \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBMICROSOFT_BIG_SSLV3_BUFFER\fR" .IP "\fBMICROSOFT_BIG_SSLV3_BUFFER\fR"
See See
SSL_CTX_\fBset_options\fR(3) \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBMICROSOFT_SESS_ID_BUG\fR" .IP "\fBMICROSOFT_SESS_ID_BUG\fR"
See SSL_CTX_\fBset_options\fR(3) See \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBMSIE_SSLV2_RSA_PADDING\fR" .IP "\fBMSIE_SSLV2_RSA_PADDING\fR"
also aliased as also aliased as
@ -12882,7 +12996,7 @@ default with OpenSSL versions that may predate the fix. Fixed in
OpenSSL 0.9.7h and OpenSSL 0.9.8a. OpenSSL 0.9.7h and OpenSSL 0.9.8a.
.br .br
.IP "\fBNETSCAPE_CHALLENGE_BUG\fR" .IP "\fBNETSCAPE_CHALLENGE_BUG\fR"
See SSL_CTX_\fBset_options\fR(3) See \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBNETSCAPE_REUSE_CIPHER_CHANGE_BUG\fR" .IP "\fBNETSCAPE_REUSE_CIPHER_CHANGE_BUG\fR"
also aliased also aliased
@ -12892,25 +13006,25 @@ OpenSSL 0.9.8q and OpenSSL 1.0.0c.
.br .br
.IP "\fBSSLEAY_080_CLIENT_DH_BUG\fR" .IP "\fBSSLEAY_080_CLIENT_DH_BUG\fR"
See See
SSL_CTX_\fBset_options\fR(3) \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBSSLREF2_REUSE_CERT_TYPE_BUG\fR" .IP "\fBSSLREF2_REUSE_CERT_TYPE_BUG\fR"
See See
SSL_CTX_\fBset_options\fR(3) \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBTLS_BLOCK_PADDING_BUG\fR" .IP "\fBTLS_BLOCK_PADDING_BUG\fR"
See SSL_CTX_\fBset_options\fR(3) See \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBTLS_D5_BUG\fR" .IP "\fBTLS_D5_BUG\fR"
See SSL_CTX_\fBset_options\fR(3) See \fBSSL_CTX_set_options\fR(3)
.br .br
.IP "\fBTLS_ROLLBACK_BUG\fR" .IP "\fBTLS_ROLLBACK_BUG\fR"
See SSL_CTX_\fBset_options\fR(3). See \fBSSL_CTX_set_options\fR(3).
This is disabled in OpenSSL 0.9.7 and later. Nobody should still This is disabled in OpenSSL 0.9.7 and later. Nobody should still
be using 0.9.6! be using 0.9.6!
.br .br
.IP "\fBTLSEXT_PADDING\fR" .IP "\fBTLSEXT_PADDING\fR"
Postfix >= 3.4. See SSL_CTX_\fBset_options\fR(3). Postfix >= 3.4. See \fBSSL_CTX_set_options\fR(3).
.br .br
.br .br
.PP .PP
@ -13291,7 +13405,7 @@ solution.
.PP .PP
If the value of the parameter is a hexadecimal long integer If the value of the parameter is a hexadecimal long integer
starting with "0x", the options corresponding to the bits specified starting with "0x", the options corresponding to the bits specified
in its value are enabled (see openssl/ssl.h and SSL_CTX_\fBset_options\fR(3)). in its value are enabled (see openssl/ssl.h and \fBSSL_CTX_set_options\fR(3)).
You can only enable options not already controlled by other Postfix You can only enable options not already controlled by other Postfix
settings. For example, you cannot disable protocols or enable settings. For example, you cannot disable protocols or enable
server cipher preference. Do not attempt to turn all features by server cipher preference. Do not attempt to turn all features by
@ -13301,16 +13415,16 @@ if/when they're no longer enabled by default. The supported values
include: include:
.IP "\fBENABLE_MIDDLEBOX_COMPAT\fR" .IP "\fBENABLE_MIDDLEBOX_COMPAT\fR"
Postfix >= 3.4. See Postfix >= 3.4. See
SSL_CTX_\fBset_options\fR(3). \fBSSL_CTX_set_options\fR(3).
.br .br
.IP "\fBLEGACY_SERVER_CONNECT\fR" .IP "\fBLEGACY_SERVER_CONNECT\fR"
See SSL_CTX_\fBset_options\fR(3). See \fBSSL_CTX_set_options\fR(3).
.br .br
.IP "\fBNO_TICKET\fR" .IP "\fBNO_TICKET\fR"
Enabled by default when needed in Enabled by default when needed in
fully\-patched Postfix >= 2.7. Not needed at all for Postfix >= fully\-patched Postfix >= 2.7. Not needed at all for Postfix >=
2.11, unless for some reason you do not want to support TLS session 2.11, unless for some reason you do not want to support TLS session
resumption. Best not set explicitly. See SSL_CTX_\fBset_options\fR(3). resumption. Best not set explicitly. See \fBSSL_CTX_set_options\fR(3).
.br .br
.IP "\fBNO_COMPRESSION\fR" .IP "\fBNO_COMPRESSION\fR"
Disable SSL compression even if Disable SSL compression even if
@ -13320,14 +13434,14 @@ and compression before encryption does not always improve security.
.IP "\fBNO_RENEGOTIATION\fR" .IP "\fBNO_RENEGOTIATION\fR"
Postfix >= 3.4. This can Postfix >= 3.4. This can
reduce opportunities for a potential CPU exhaustion attack. See reduce opportunities for a potential CPU exhaustion attack. See
SSL_CTX_\fBset_options\fR(3). \fBSSL_CTX_set_options\fR(3).
.br .br
.IP "\fBNO_SESSION_RESUMPTION_ON_RENEGOTIATION\fR" .IP "\fBNO_SESSION_RESUMPTION_ON_RENEGOTIATION\fR"
Postfix Postfix
>= 3.4. See SSL_CTX_\fBset_options\fR(3). >= 3.4. See \fBSSL_CTX_set_options\fR(3).
.br .br
.IP "\fBPRIORITIZE_CHACHA\fR" .IP "\fBPRIORITIZE_CHACHA\fR"
Postfix >= 3.4. See SSL_CTX_\fBset_options\fR(3). Postfix >= 3.4. See \fBSSL_CTX_set_options\fR(3).
.br .br
.br .br
.PP .PP

12
postfix/man/man8/smtp.8
View File

@ -482,9 +482,9 @@ when TLS is not already enabled for that server.
Optional lookup tables with the Postfix SMTP client TLS security Optional lookup tables with the Postfix SMTP client TLS security
policy by next\-hop destination; when a non\-empty value is specified, policy by next\-hop destination; when a non\-empty value is specified,
this overrides the obsolete smtp_tls_per_site parameter. this overrides the obsolete smtp_tls_per_site parameter.
.IP "\fBsmtp_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR" .IP "\fBsmtp_tls_mandatory_protocols (see 'postconf -d' output)\fR"
List of SSL/TLS protocols that the Postfix SMTP client will use with TLS protocols that the Postfix SMTP client will use with mandatory
mandatory TLS encryption. TLS encryption.
.IP "\fBsmtp_tls_scert_verifydepth (9)\fR" .IP "\fBsmtp_tls_scert_verifydepth (9)\fR"
The verification depth for remote SMTP server certificates. The verification depth for remote SMTP server certificates.
.IP "\fBsmtp_tls_secure_cert_match (nexthop, dot\-nexthop)\fR" .IP "\fBsmtp_tls_secure_cert_match (nexthop, dot\-nexthop)\fR"
@ -532,9 +532,9 @@ The message digest algorithm used to construct remote SMTP server
certificate fingerprints. certificate fingerprints.
.PP .PP
Available in Postfix version 2.6 and later: Available in Postfix version 2.6 and later:
.IP "\fBsmtp_tls_protocols (!SSLv2, !SSLv3)\fR" .IP "\fBsmtp_tls_protocols (see postconf -d output)\fR"
List of TLS protocols that the Postfix SMTP client will exclude or TLS protocols that the Postfix SMTP client will use with
include with opportunistic TLS encryption. opportunistic TLS encryption.
.IP "\fBsmtp_tls_ciphers (medium)\fR" .IP "\fBsmtp_tls_ciphers (medium)\fR"
The minimum TLS cipher grade that the Postfix SMTP client The minimum TLS cipher grade that the Postfix SMTP client
will use with opportunistic TLS encryption. will use with opportunistic TLS encryption.

12
postfix/man/man8/smtpd.8
View File

@ -439,9 +439,9 @@ use with mandatory TLS encryption.
.IP "\fBsmtpd_tls_mandatory_exclude_ciphers (empty)\fR" .IP "\fBsmtpd_tls_mandatory_exclude_ciphers (empty)\fR"
Additional list of ciphers or cipher types to exclude from the Additional list of ciphers or cipher types to exclude from the
Postfix SMTP server cipher list at mandatory TLS security levels. Postfix SMTP server cipher list at mandatory TLS security levels.
.IP "\fBsmtpd_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR" .IP "\fBsmtpd_tls_mandatory_protocols (see 'postconf -d' output)\fR"
The SSL/TLS protocols accepted by the Postfix SMTP server with TLS protocols accepted by the Postfix SMTP server with mandatory TLS
mandatory TLS encryption. encryption.
.IP "\fBsmtpd_tls_received_header (no)\fR" .IP "\fBsmtpd_tls_received_header (no)\fR"
Request that the Postfix SMTP server produces Received: message Request that the Postfix SMTP server produces Received: message
headers that include information about the protocol and cipher used, headers that include information about the protocol and cipher used,
@ -476,9 +476,9 @@ fingerprints or public key fingerprints (Postfix 2.9 and later) for
\fBcheck_ccert_access\fR and \fBpermit_tls_clientcerts\fR. \fBcheck_ccert_access\fR and \fBpermit_tls_clientcerts\fR.
.PP .PP
Available in Postfix version 2.6 and later: Available in Postfix version 2.6 and later:
.IP "\fBsmtpd_tls_protocols (!SSLv2, !SSLv3)\fR" .IP "\fBsmtpd_tls_protocols (see postconf -d output)\fR"
List of TLS protocols that the Postfix SMTP server will exclude TLS protocols accepted by the Postfix SMTP server with opportunistic
or include with opportunistic TLS encryption. TLS encryption.
.IP "\fBsmtpd_tls_ciphers (medium)\fR" .IP "\fBsmtpd_tls_ciphers (medium)\fR"
The minimum TLS cipher grade that the Postfix SMTP server The minimum TLS cipher grade that the Postfix SMTP server
will use with opportunistic TLS encryption. will use with opportunistic TLS encryption.

2
postfix/mantools/postconf2man
View File

@ -88,7 +88,7 @@ while(<>) {
$block =~ s/\s+\n/\n/g; $block =~ s/\s+\n/\n/g;
$block =~ s/^\n//g; $block =~ s/^\n//g;
$block =~ s/\s*<\s*nroffescape\s+([^ >]+)\s*>\s*/\n\1\n/g; $block =~ s/\s*<\s*nroffescape\s+([^ >]+)\s*>\s*/\n\1\n/g;
$block =~ s/([a-z][_a-zA-Z0-9-]*)(\([0-9]\))/\\fB\1\\fR\2/g; $block =~ s/([A-Za-z][_a-zA-Z0-9-]*)(\([0-9]\))/\\fB\1\\fR\2/g;
print $block; print $block;
$wantpp = !($block =~ /^\.(SH|IP)/); $wantpp = !($block =~ /^\.(SH|IP)/);
} }

47
postfix/proto/TLS_README.html
View File

@ -179,10 +179,10 @@ configurations will not accidentally enable TLS without certificates. </p>
<p> Note that server certificates are <b>not</b> optional in TLS 1.3. To <p> Note that server certificates are <b>not</b> optional in TLS 1.3. To
run without certificates you'd have to disable the TLS 1.3 protocol by run without certificates you'd have to disable the TLS 1.3 protocol by
including '!TLSv1.3' in "smtpd_tls_protocols" and perhaps also including "&lt;=TLSv1.2" (or, for Postfix &lt; 3.6, "!TLSv1.3") in
"smtpd_tls_mandatory_protocols". It is simpler instead to just "smtpd_tls_protocols" and perhaps also "smtpd_tls_mandatory_protocols".
configure a certificate chain. Certificate-less operation is not It is simpler instead to just configure a certificate chain.
recommended. <p> Certificate-less operation is not recommended. <p>
<p> RSA, DSA and ECDSA (Postfix &ge; 2.6) certificates are supported. <p> RSA, DSA and ECDSA (Postfix &ge; 2.6) certificates are supported.
Most sites only have RSA certificates. You can configure all three Most sites only have RSA certificates. You can configure all three
@ -891,7 +891,7 @@ after the middle of 2015; older releases only disable SSLv2 for
mandatory TLS. The mandatory TLS protocol list is specified via the mandatory TLS. The mandatory TLS protocol list is specified via the
smtpd_tls_mandatory_protocols configuration parameter. The smtpd_tls_mandatory_protocols configuration parameter. The
smtpd_tls_protocols parameter (Postfix &ge; 2.6) smtpd_tls_protocols parameter (Postfix &ge; 2.6)
controls the SSL/TLS protocols used with opportunistic TLS. </p> controls the TLS protocols used with opportunistic TLS. </p>
<p> Note that the OpenSSL library only supports protocol exclusion <p> Note that the OpenSSL library only supports protocol exclusion
(not inclusion). For this reason, Postfix can exclude only protocols (not inclusion). For this reason, Postfix can exclude only protocols
@ -909,8 +909,8 @@ that TLSv1.3 be explicitly disabled. Therefore, they are not
recommended, it is better and simpler to just configure a suitable recommended, it is better and simpler to just configure a suitable
certificate. </p> certificate. </p>
<p> Example, MSA that requires TLSv1 or higher, not SSLv2 or SSLv3, <p> Example, MSA that requires TLSv1.2 or higher, with high grade
with high grade ciphers: </p> ciphers: </p>
<blockquote> <blockquote>
<pre> <pre>
@ -920,10 +920,10 @@ with high grade ciphers: </p>
smtpd_tls_mandatory_ciphers = high smtpd_tls_mandatory_ciphers = high
smtpd_tls_mandatory_exclude_ciphers = aNULL, MD5 smtpd_tls_mandatory_exclude_ciphers = aNULL, MD5
smtpd_tls_security_level = encrypt smtpd_tls_security_level = encrypt
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_mandatory_protocols = &gt;=TLSv1.2
# Legacy syntax: # Legacy syntax:
smtpd_tls_mandatory_protocols = TLSv1 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
</blockquote> </blockquote>
@ -1263,9 +1263,10 @@ just in case the transport table entries are not specified consistently. </p>
submission 587/tcp msa # mail message submission submission 587/tcp msa # mail message submission
/etc/postfix/tls_policy: /etc/postfix/tls_policy:
[example.net]:587 encrypt protocols=TLSv1 ciphers=high # Postfix &ge; 3.6 "protocols" syntax
[example.net]:msa encrypt protocols=TLSv1 ciphers=high [example.net]:587 encrypt protocols=&gt;=TLSv1.2 ciphers=high
[example.net]:submission encrypt protocols=TLSv1 ciphers=high # Legacy "protocols" syntax
[example.net]:msa encrypt protocols=!SSLv2:!SSLv3 ciphers=high
</pre> </pre>
</blockquote> </blockquote>
@ -2398,8 +2399,10 @@ Example:
[thumb.example.org] fingerprint [thumb.example.org] fingerprint
match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f match=b6:b4:72:34:e2:59:cd:fb:...:0d:4d:cc:2c:7d:84:de:e6:2f
match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76 match=51:e9:af:2e:1e:40:1f:de:...:35:2d:09:16:31:5a:eb:82:76
# Postfix 2.6 and later # Postfix &ge; 3.6 "protocols" syntax
example.info may protocols=!SSLv2 ciphers=medium exclude=3DES example.info may protocols=&gt;=TLSv1 ciphers=medium exclude=3DES
# Legacy protocols syntax
example.info may protocols=!SSLv2:!SSLv3 ciphers=medium exclude=3DES
</pre> </pre>
</blockquote> </blockquote>
@ -2494,7 +2497,7 @@ SMTP client will by default disable SSLv2 and SSLv3. The mandatory
TLS protocol list is specified via the TLS protocol list is specified via the
smtp_tls_mandatory_protocols configuration parameter. The corresponding smtp_tls_mandatory_protocols configuration parameter. The corresponding
smtp_tls_protocols parameter (Postfix &ge; 2.6) controls smtp_tls_protocols parameter (Postfix &ge; 2.6) controls
the SSL/TLS protocols used with opportunistic TLS. </p> the TLS protocols used with opportunistic TLS. </p>
<p> Example: </p> <p> Example: </p>
@ -2504,13 +2507,13 @@ the SSL/TLS protocols used with opportunistic TLS. </p>
smtp_tls_mandatory_ciphers = medium smtp_tls_mandatory_ciphers = medium
smtp_tls_mandatory_exclude_ciphers = RC4, MD5 smtp_tls_mandatory_exclude_ciphers = RC4, MD5
smtp_tls_exclude_ciphers = aNULL smtp_tls_exclude_ciphers = aNULL
# Preferred form with Postfix &ge; 2.5:
smtp_tls_mandatory_protocols = !SSLv2
# Legacy form for Postfix &lt; 2.5:
smtp_tls_mandatory_protocols = SSLv3, TLSv1
# Also available with Postfix &ge; 2.6:
smtp_tls_ciphers = medium smtp_tls_ciphers = medium
smtp_tls_protocols = !SSLv2 # Preferred form with Postfix &ge; 3.6:
smtp_tls_mandatory_protocols = &gt;=TLSv1.2
smtp_tls_protocols = &gt;=TLSv1
# Legacy form for Postfix &lt; 3.6:
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_protocols = !SSLv2,!SSLv3
</pre> </pre>
</blockquote> </blockquote>

413
postfix/proto/postconf.proto
View File

@ -11299,74 +11299,92 @@ configurations in environments where DNS security is not assured. </p>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
%PARAM smtp_tls_mandatory_protocols !SSLv2, !SSLv3 %PARAM smtp_tls_mandatory_protocols see "postconf -d" output
<p> List of SSL/TLS protocols that the Postfix SMTP client will use with <p> TLS protocols that the Postfix SMTP client will use with mandatory
mandatory TLS encryption. In main.cf the values are separated by TLS encryption. In main.cf the values are separated by whitespace,
whitespace, commas or colons. In the policy table "protocols" attribute commas or colons. In the policy table "protocols" attribute (see
(see smtp_tls_policy_maps) the only valid separator is colon. An smtp_tls_policy_maps) the only valid separator is colon. An empty value
empty value means allow all protocols. The valid protocol names, (see means allow all protocols. </p>
<b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" and "TLSv1". The
default value is "!SSLv2, !SSLv3" for Postfix releases after the
middle of 2015, "!SSLv2" for older releases. </p>
<p> With Postfix &ge; 2.5 the parameter syntax was expanded to support <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"smtp_tls_mandatory_protocols = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"SSLv3" set "smtp_tls_mandatory_protocols = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below. </p>
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics.
</p>
<p> The range of protocols advertised by an SSL/TLS client must be <p> As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set a lowest acceptable TLS protocol version
higher version implicitly disables all versions above that higher version. and/or a highest acceptable TLS protocol version. To set the lower
Thus, for example (assuming the OpenSSL library supports both SSLv2 bound include an element of the form: "&gt;=<i>version</i>" where
and SSLv3): <i>version</i> is a either one of the TLS protocol names listed above,
</p> or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote> <blockquote>
<pre> <pre>
smtp_tls_mandatory_protocols = !SSLv2, !TLSv1 # Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtp_tls_mandatory_protocols = &gt;=TLSv1.2, &lt;=0305
# Allow only TLS 1.2 and up:
smtp_tls_mandatory_protocols = &gt;=0x0303
</pre> </pre>
</blockquote> </blockquote>
<p> also disables any protocols version higher than TLSv1 leaving
only "SSLv3" enabled. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
and "TLSv1.2". When Postfix &le; 2.5 is linked against OpenSSL 1.0.1 version, and the protocol range is configured via protocol exclusions.
or later, these, or any other new protocol versions, cannot be To require at least TLS 1.0, set "smtp_tls_mandatory_protocols = !SSLv2,
disabled except by also disabling "TLSv1" (typically leaving just !SSLv3". Listing the protocols to include, rather than protocols to
"SSLv3"). The latest patch levels of Postfix &ge; 2.6, and all exclude, is supported, but not recommended. The exclusion syntax more
versions of Postfix &ge; 2.10 can explicitly disable support for accurately matches the underlying OpenSSL interface. </p>
"TLSv1.1" or "TLSv1.2". </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> When using the exclusion syntax, take care to ensure that the range
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) of protocols supported by the Postfix SMTP client is contiguous. When
this can be disabled, if need be, via "!TLSv1.3". </p> a protocol version is enabled, disabling any higher version implicitly
disables all versions above that higher version. Thus, for example: </p>
<p> At the <a href="TLS_README.html#client_tls_dane">dane</a> and <blockquote>
<a href="TLS_README.html#client_tls_dane">dane-only</a> security <pre>
levels, when usable TLSA records are obtained for the remote SMTP smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1.1
server, the Postfix SMTP client is obligated to include the SNI TLS </pre>
extension in its SSL client hello message. This may help the remote </blockquote>
SMTP server live up to its promise to provide a certificate that
matches its TLSA records. Since TLS extensions require TLS 1.0 or <p> also disables any protocols version higher than TLSv1.1 leaving
later, the Postfix SMTP client must disable "SSLv2" and "SSLv3" when only "TLSv1" enabled. </p>
SNI is required. If you use "dane" or "dane-only" do not disable
TLSv1, except perhaps via the policy table for destinations which <p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
you are sure will support "TLSv1.1" or "TLSv1.2". </p> this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> While the vast majority of SMTP servers with DANE TLSA records now
support at least TLS 1.2, a few still only support TLS 1.0. If you use
"dane" or "dane-only" it is best to not disable TLSv1, except perhaps
via the policy table for destinations which you are sure will support
"TLSv1.2". </p>
<p> See the documentation of the smtp_tls_policy_maps parameter and <p> See the documentation of the smtp_tls_policy_maps parameter and
TLS_README for more information about security levels. </p> TLS_README for more information about security levels. </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_protocols = &gt;=TLSv1.2, &lt;=TLSv1.3
# Legacy syntax: # Legacy syntax:
smtp_tls_mandatory_protocols = TLSv1 smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -11495,7 +11513,7 @@ configuration parameter. See there for details. </p>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
%PARAM lmtp_tls_mandatory_protocols !SSLv2, !SSLv3 %PARAM lmtp_tls_mandatory_protocols see postconf -d output
<p> The LMTP-specific version of the smtp_tls_mandatory_protocols <p> The LMTP-specific version of the smtp_tls_mandatory_protocols
configuration parameter. See there for details. </p> configuration parameter. See there for details. </p>
@ -11516,43 +11534,69 @@ configuration parameter. See there for details. </p>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
%PARAM smtpd_tls_mandatory_protocols !SSLv2, !SSLv3 %PARAM smtpd_tls_mandatory_protocols see "postconf -d" output
<p> The SSL/TLS protocols accepted by the Postfix SMTP server with <p> TLS protocols accepted by the Postfix SMTP server with mandatory TLS
mandatory TLS encryption. If the list is empty, the server supports encryption. If the list is empty, the server supports all available TLS
all available SSL/TLS protocol versions. A non-empty value is a protocol versions. A non-empty value is a list of protocol names to
list of protocol names separated by whitespace, commas or colons. include or exclude, separated by whitespace, commas or colons. </p>
The supported protocol names are "SSLv2", "SSLv3" and "TLSv1", and
are not case sensitive. The default value is "!SSLv2, !SSLv3" for
Postfix releases after the middle of 2015, "!SSLv2" for older
releases. </p>
<p> With Postfix &ge; 2.5 the parameter syntax was expanded to support <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
protocol exclusions. One can explicitly exclude "SSLv2" by setting "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
"smtpd_tls_mandatory_protocols = !SSLv2". To exclude both "SSLv2" and Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"SSLv3" set "smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3". Listing the lowest supported TLS protocol version (see below). Older releases
the protocols to include, rather than protocols to exclude, is use the "!" exclusion syntax, also described below. </p>
supported, but not recommended. The exclusion form more closely
matches the underlying OpenSSL interface semantics. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> As of Postfix 3.6, the preferred way to limit the range of
and "TLSv1.2". When Postfix &le; 2.5 is linked against OpenSSL 1.0.1 acceptable protocols is to set the lowest acceptable TLS protocol
or later, these, or any other new protocol versions, cannot be version and/or the highest acceptable TLS protocol version. To set the
disabled. The latest patch levels of Postfix &ge; 2.6, and all lower bound include an element of the form: "&gt;=<i>version</i>" where
versions of Postfix &ge; 2.10 can disable support for "TLSv1.1" or <i>version</i> is a either one of the TLS protocol names listed above,
"TLSv1.2". </p> or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> Hexadecimal protocol numbers make it possible to specify protocol
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) bounds for TLS versions that are known to OpenSSL, but might not be
this can be disabled, if need be, via "!TLSv1.3". </p> known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.2 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtpd_tls_mandatory_protocols = &gt;=TLSv1.2, &lt;=0305
# Allow only TLS 1.2 and up:
smtpd_tls_mandatory_protocols = &gt;=0x0303
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "smtpd_tls_mandatory_protocols =
!SSLv2, !SSLv3". Listing the protocols to include, rather than
protocols to exclude, is supported, but not recommended. The exclusion
form more accurately matches the underlying OpenSSL interface. </p>
<p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 2.5: # Preferred syntax with Postfix &ge; 3.6:
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_mandatory_protocols = &gt;=TLSv1.2, &lt;=TLSv1.3
# Legacy syntax: # Legacy syntax:
smtpd_tls_mandatory_protocols = TLSv1 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -11674,12 +11718,13 @@ smtp_tls_security_level = none
<pre> <pre>
# Opportunistic TLS. # Opportunistic TLS.
smtp_tls_security_level = may smtp_tls_security_level = may
# Postfix &ge; 2.6:
# Do not tweak opportunistic ciphers or protocol unless it is essential # Do not tweak opportunistic ciphers or protocol unless it is essential
# to do so (if a security vulnerability is found in the SSL library that # to do so (if a security vulnerability is found in the SSL library that
# can be mitigated by disabling a particular protocol or raising the # can be mitigated by disabling a particular protocol or raising the
# cipher grade from "export" to "low" or "medium"). # cipher grade).
smtp_tls_ciphers = export smtp_tls_ciphers = medium
smtp_tls_protocols = &gt;=TLSv1
# Legacy (Postfix &lt; 3.6) syntax:
smtp_tls_protocols = !SSLv2, !SSLv3 smtp_tls_protocols = !SSLv2, !SSLv3
</pre> </pre>
@ -11690,33 +11735,27 @@ smtp_tls_mandatory_ciphers = high
</pre> </pre>
<pre> <pre>
# Mandatory TLS verification of hostname or nexthop domain. # Authenticated TLS 1.2 or better matching the nexthop domain or a
smtp_tls_security_level = verify # subdomain.
smtp_tls_mandatory_ciphers = high
smtp_tls_verify_cert_match = hostname, nexthop, dot-nexthop
</pre>
<pre>
# Secure channel TLS with exact nexthop name match.
smtp_tls_security_level = secure smtp_tls_security_level = secure
smtp_tls_mandatory_protocols = TLSv1
smtp_tls_mandatory_ciphers = high smtp_tls_mandatory_ciphers = high
smtp_tls_secure_cert_match = nexthop smtp_tls_mandatory_protocols = &gt;=TLSv1.2
smtp_tls_secure_cert_match = nexthop, dot-nexthop
</pre> </pre>
<pre> <pre>
# Certificate fingerprint verification (Postfix &ge; 2.5). # Certificate fingerprint verification (Postfix &ge; 2.5).
# The CA-less "fingerprint" security level only scales to a limited # The CA-less "fingerprint" security level only scales to a limited
# number of destinations. As a global default rather than a per-site # number of destinations. As a global default rather than a per-site
# setting, this is practical when mail for all recipients is sent # setting, this is practical only when mail for all recipients is sent
# to a central mail hub. # to a central mail hub.
relayhost = [mailhub.example.com] relayhost = [mailhub.example.com]
smtp_tls_security_level = fingerprint smtp_tls_security_level = fingerprint
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtp_tls_mandatory_protocols = &gt;=TLSv1.2
smtp_tls_mandatory_ciphers = high smtp_tls_mandatory_ciphers = high
smtp_tls_fingerprint_cert_match = smtp_tls_fingerprint_cert_match =
3D:95:34:51:24:66:33:B9:D2:40:99:C0:C1:17:0B:D1 3D:95:34:51:...:40:99:C0:C1
EC:3B:2D:B0:5B:B1:FB:6D:20:A3:9D:72:F6:8D:12:35 EC:3B:2D:B0:...:A3:9D:72:F6
</pre> </pre>
<p> This feature is available in Postfix 2.3 and later. </p> <p> This feature is available in Postfix 2.3 and later. </p>
@ -12640,95 +12679,153 @@ the hostname and IP address. The logging format is "host[address]:port".
<p> This feature is available in Postfix 2.5 and later. </p> <p> This feature is available in Postfix 2.5 and later. </p>
%PARAM smtp_tls_protocols !SSLv2, !SSLv3 %PARAM smtp_tls_protocols see postconf -d output
<p> List of TLS protocols that the Postfix SMTP client will exclude or <p> TLS protocols that the Postfix SMTP client will use with
include with opportunistic TLS encryption. The default value is opportunistic TLS encryption. In main.cf the values are separated by
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, whitespace, commas or colons. In the policy table "protocols" attribute
"!SSLv2" for older releases. Before Postfix 2.6, the Postfix SMTP (see smtp_tls_policy_maps) the only valid separator is colon. An empty
client would use all protocols with opportunistic TLS. </p> value means allow all protocols. </p>
<p> In main.cf the values are separated by whitespace, commas or <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
colons. In the policy table (see smtp_tls_policy_maps) the only valid "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
separator is colon. An empty value means allow all protocols. The valid Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
protocol names, (see <b>SSL_get_version(3)</b>), are "SSLv2", "SSLv3" the lowest supported TLS protocol version (see below). Older releases
and "TLSv1". </p> use the "!" exclusion syntax, also described below. </p>
<p> The range of protocols advertised by an SSL/TLS client must be <p> As of Postfix 3.6, the preferred way to limit the range of
contiguous. When a protocol version is enabled, disabling any acceptable protocols is to set the lowest acceptable TLS protocol
higher version implicitly disables all versions above that higher version. version and/or the highest acceptable TLS protocol version. To set the
Thus, for example (assuming the OpenSSL library supports both SSLv2 lower bound include an element of the form: "&gt;=<i>version</i>" where
and SSLv3): <i>version</i> is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> Hexadecimal protocol numbers make it possible to specify protocol
bounds for TLS versions that are known to OpenSSL, but might not be
known to Postfix. They cannot be used with the legacy exclusion syntax.
Leading "0" or "0x" prefixes are supported, but not required.
Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
"TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtp_tls_protocols = &gt;=TLSv1, &lt;=0305
# Allow only TLS 1.0 and up:
smtp_tls_protocols = &gt;=0x0301
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "smtp_tls_protocols = !SSLv2, !SSLv3".
Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface. </p>
<p> When using the exclusion syntax, take care to ensure that the range of
protocols advertised by an SSL/TLS client is contiguous. When a protocol
version is enabled, disabling any higher version implicitly disables all
versions above that higher version. Thus, for example:
</p> </p>
<blockquote> <blockquote>
<pre> <pre>
smtp_tls_protocols = !SSLv2, !TLSv1 smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1.1
</pre> </pre>
</blockquote> </blockquote>
<p> also disables any protocols version higher than TLSv1 leaving <p> also disables any protocols version higher than TLSv1.1 leaving
only "SSLv3" enabled. </p> only "TLSv1" enabled. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
and "TLSv1.2". The latest patch levels of Postfix &ge; 2.6, and all this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
versions of Postfix &ge; 2.10 can explicitly disable support for releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
"TLSv1.1" or "TLSv1.2"</p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2)
this can be disabled, if need be, via "!TLSv1.3". </p>
<p> To include a protocol list its name, to exclude it, prefix the name
with a "!" character. To exclude SSLv2 for opportunistic TLS set
"smtp_tls_protocols = !SSLv2". To exclude both "SSLv2" and "SSLv3" set
"smtp_tls_protocols = !SSLv2, !SSLv3". Explicitly listing the protocols to
include, rather than protocols to exclude, is supported, but not
recommended. The exclusion form more closely matches the underlying
OpenSSL interface semantics. </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# TLSv1 or better: # Preferred syntax with Postfix &ge; 3.6:
smtp_tls_protocols = &gt;=TLSv1, &lt;=TLSv1.3
# Legacy syntax:
smtp_tls_protocols = !SSLv2, !SSLv3 smtp_tls_protocols = !SSLv2, !SSLv3
</pre> </pre>
<p> This feature is available in Postfix 2.6 and later. </p> <p> This feature is available in Postfix 2.6 and later. </p>
%PARAM smtpd_tls_protocols !SSLv2, !SSLv3 %PARAM smtpd_tls_protocols see postconf -d output
<p> List of TLS protocols that the Postfix SMTP server will exclude <p> TLS protocols accepted by the Postfix SMTP server with opportunistic
or include with opportunistic TLS encryption. The default value is TLS encryption. If the list is empty, the server supports all available
"!SSLv2, !SSLv3" for Postfix releases after the middle of 2015, TLS protocol versions. A non-empty value is a list of protocol names to
empty for older releases allowing all protocols to be include or exclude, separated by whitespace, commas or colons. </p>
used with opportunistic TLS. A non-empty value is a list of protocol
names separated by whitespace, commas or colons. The supported
protocol names are "SSLv2", "SSLv3" and "TLSv1", and are not case
sensitive. </p>
<p> Note: As of OpenSSL 1.0.1 two new protocols are defined, "TLSv1.1" <p> The valid protocol names (see SSL_get_version(3)) are "SSLv2",
and "TLSv1.2". The latest patch levels of Postfix &ge; 2.6, and all "SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2" and "TLSv1.3". Starting with
versions of Postfix &ge; 2.10 can disable support for "TLSv1.1" or Postfix 3.6, the default value is "&gt;=TLSv1", which sets TLS 1.0 as
"TLSv1.2". </p> the lowest supported TLS protocol version (see below). Older releases
use the "!" exclusion syntax, also described below. </p>
<p> OpenSSL 1.1.1 introduces support for "TLSv1.3". With Postfix <p> As of Postfix 3.6, the preferred way to limit the range of
&ge; 3.4 (or patch releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2) acceptable protocols is to set the lowest acceptable TLS protocol
this can be disabled, if need be, via "!TLSv1.3". </p> version and/or the highest acceptable TLS protocol version. To set the
lower bound include an element of the form: "&gt;=<i>version</i>" where
<i>version</i> is a either one of the TLS protocol names listed above,
or a hexadecimal number corresponding to the desired TLS protocol
version (0301 for TLS 1.0, 0302 for TLS 1.1, etc.). For the upper
bound, use "&lt;=<i>version</i>". There must be no whitespace between
the "&gt;=" or "&lt;=" symbols and the protocol name or number. </p>
<p> To include a protocol list its name, to exclude it, prefix the name <p> Hexadecimal protocol numbers make it possible to specify protocol
with a "!" character. To exclude SSLv2 for opportunistic TLS set bounds for TLS versions that are known to OpenSSL, but might not be
"smtpd_tls_protocols = !SSLv2". To exclude both "SSLv2" and "SSLv3" set known to Postfix. They cannot be used with the legacy exclusion syntax.
"smtpd_tls_protocols = !SSLv2, !SSLv3". Explicitly listing the protocols to Leading "0" or "0x" prefixes are supported, but not required.
include, rather than protocols to exclude, is supported, but not Therefore, "301", "0301", "0x301" and "0x0301" are all equivalent to
recommended. The exclusion form more closely matches the underlying "TLSv1". Hexadecimal versions unknown to OpenSSL will fail to set the
OpenSSL interface semantics. </p> upper or lower bound, and a warning will be logged. Hexadecimal
versions should only be used when Postfix is linked with some future
version of OpenSSL that supports TLS 1.4 or later, but Postfix does not
yet support a symbolic name for that protocol version. </p>
<p>Hexadecimal example (Postfix &ge; 3.6):</p>
<blockquote>
<pre>
# Allow only TLS 1.0 through (hypothetical) TLS 1.4, once supported
# in some future version of OpenSSL (presently a warning is logged).
smtpd_tls_protocols = &gt;=TLSv1, &lt;=0305
# Allow only TLS 1.0 and up:
smtpd_tls_protocols = &gt;=0x0301
</pre>
</blockquote>
<p> With Postfix &lt; 3.6 there is no support for a minimum or maximum
version, and the protocol range is configured via protocol exclusions.
To require at least TLS 1.0, set "smtpd_tls_protocols = !SSLv2, !SSLv3".
Listing the protocols to include, rather than protocols to exclude, is
supported, but not recommended. The exclusion form more accurately
matches the underlying OpenSSL interface. </p>
<p> Support for "TLSv1.3" was introduced in OpenSSL 1.1.1. Disabling
this protocol via "!TLSv1.3" is supported since Postfix 3.4 (or patch
releases &ge; 3.0.14, 3.1.10, 3.2.7 and 3.3.2). </p>
<p> Example: </p> <p> Example: </p>
<pre> <pre>
# Preferred syntax with Postfix &ge; 3.6:
smtpd_tls_protocols = &gt;=TLSv1, &lt;=TLSv1.3
# Legacy syntax:
smtpd_tls_protocols = !SSLv2, !SSLv3 smtpd_tls_protocols = !SSLv2, !SSLv3
</pre> </pre>
<p> This feature is available in Postfix 2.6 and later. </p> <p> This feature is available in Postfix 2.6 and later. </p>
%PARAM lmtp_tls_protocols !SSLv2, !SSLv3 %PARAM lmtp_tls_protocols see postconf -d output
<p> The LMTP-specific version of the smtp_tls_protocols configuration <p> The LMTP-specific version of the smtp_tls_protocols configuration
parameter. See there for details. </p> parameter. See there for details. </p>
@ -12874,7 +12971,7 @@ EC algorithms have not been disabled by the vendor. </p>
<p> The Postfix SMTP server security grade for ephemeral elliptic-curve <p> The Postfix SMTP server security grade for ephemeral elliptic-curve
Diffie-Hellman (EECDH) key exchange. As of Postfix 3.6, the value of Diffie-Hellman (EECDH) key exchange. As of Postfix 3.6, the value of
this parameter is always ignored, and Postfix behaves as though th this parameter is always ignored, and Postfix behaves as though the
<b>auto</b> value (described below) was chosen. <b>auto</b> value (described below) was chosen.
</p> </p>

12
postfix/src/global/mail_params.h
View File

@ -1336,11 +1336,11 @@ extern char *var_smtpd_tls_CAfile;
extern char *var_smtpd_tls_CApath; extern char *var_smtpd_tls_CApath;
#define VAR_SMTPD_TLS_PROTO "smtpd_tls_protocols" #define VAR_SMTPD_TLS_PROTO "smtpd_tls_protocols"
#define DEF_SMTPD_TLS_PROTO "!SSLv2, !SSLv3" #define DEF_SMTPD_TLS_PROTO ">=TLSv1"
extern char *var_smtpd_tls_proto; extern char *var_smtpd_tls_proto;
#define VAR_SMTPD_TLS_MAND_PROTO "smtpd_tls_mandatory_protocols" #define VAR_SMTPD_TLS_MAND_PROTO "smtpd_tls_mandatory_protocols"
#define DEF_SMTPD_TLS_MAND_PROTO "!SSLv2, !SSLv3" #define DEF_SMTPD_TLS_MAND_PROTO ">=TLSv1"
extern char *var_smtpd_tls_mand_proto; extern char *var_smtpd_tls_mand_proto;
#define VAR_SMTPD_TLS_CIPH "smtpd_tls_ciphers" #define VAR_SMTPD_TLS_CIPH "smtpd_tls_ciphers"
@ -1571,15 +1571,15 @@ extern int var_lmtp_tls_scache_timeout;
extern char *var_smtp_tls_policy; extern char *var_smtp_tls_policy;
#define VAR_SMTP_TLS_PROTO "smtp_tls_protocols" #define VAR_SMTP_TLS_PROTO "smtp_tls_protocols"
#define DEF_SMTP_TLS_PROTO "!SSLv2, !SSLv3" #define DEF_SMTP_TLS_PROTO ">=TLSv1"
#define VAR_LMTP_TLS_PROTO "lmtp_tls_protocols" #define VAR_LMTP_TLS_PROTO "lmtp_tls_protocols"
#define DEF_LMTP_TLS_PROTO "!SSLv2, !SSLv3" #define DEF_LMTP_TLS_PROTO ">=TLSv1"
extern char *var_smtp_tls_proto; extern char *var_smtp_tls_proto;
#define VAR_SMTP_TLS_MAND_PROTO "smtp_tls_mandatory_protocols" #define VAR_SMTP_TLS_MAND_PROTO "smtp_tls_mandatory_protocols"
#define DEF_SMTP_TLS_MAND_PROTO "!SSLv2, !SSLv3" #define DEF_SMTP_TLS_MAND_PROTO ">=TLSv1"
#define VAR_LMTP_TLS_MAND_PROTO "lmtp_tls_mandatory_protocols" #define VAR_LMTP_TLS_MAND_PROTO "lmtp_tls_mandatory_protocols"
#define DEF_LMTP_TLS_MAND_PROTO "!SSLv2, !SSLv3" #define DEF_LMTP_TLS_MAND_PROTO ">=TLSv1"
extern char *var_smtp_tls_mand_proto; extern char *var_smtp_tls_mand_proto;
#define VAR_SMTP_TLS_VFY_CMATCH "smtp_tls_verify_cert_match" #define VAR_SMTP_TLS_VFY_CMATCH "smtp_tls_verify_cert_match"

2
postfix/src/global/mail_version.h
View File

@ -20,7 +20,7 @@
* Patches change both the patchlevel and the release date. Snapshots have no * Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only. * patchlevel; they change the release date only.
*/ */
#define MAIL_RELEASE_DATE "20200720" #define MAIL_RELEASE_DATE "20200725"
#define MAIL_VERSION_NUMBER "3.6" #define MAIL_VERSION_NUMBER "3.6"
#ifdef SNAPSHOT #ifdef SNAPSHOT

6
postfix/src/posttls-finger/posttls-finger.c
View File

@ -224,8 +224,8 @@
/* parameter \fIname\fR with \fIvalue\fR. Possible use-cases include /* parameter \fIname\fR with \fIvalue\fR. Possible use-cases include
/* overriding the values of TLS library parameters, or "myhostname" to /* overriding the values of TLS library parameters, or "myhostname" to
/* configure the SMTP EHLO name sent to the remote server. /* configure the SMTP EHLO name sent to the remote server.
/* .IP "\fB-p \fIprotocols\fR (default: !SSLv2)" /* .IP "\fB-p \fIprotocols\fR (default: >=TLSv1)"
/* List of TLS protocols that posttls-finger will exclude or include. See /* TLS protocols that posttls-finger will exclude or include. See
/* smtp_tls_mandatory_protocols for details. /* smtp_tls_mandatory_protocols for details.
/* .IP "\fB-P \fICApath/\fR (default: none)" /* .IP "\fB-P \fICApath/\fR (default: none)"
/* The OpenSSL CApath/ directory (indexed via c_rehash(1)) for remote /* The OpenSSL CApath/ directory (indexed via c_rehash(1)) for remote
@ -1806,7 +1806,7 @@ static void parse_options(STATE *state, int argc, char *argv[])
state->max_reconnect = 5; state->max_reconnect = 5;
state->wrapper_mode = 0; state->wrapper_mode = 0;
#ifdef USE_TLS #ifdef USE_TLS
state->protocols = mystrdup("!SSLv2"); state->protocols = mystrdup(">=TLSv1");
state->grade = mystrdup("medium"); state->grade = mystrdup("medium");
#endif #endif
memset((void *) &state->options, 0, sizeof(state->options)); memset((void *) &state->options, 0, sizeof(state->options));

12
postfix/src/smtp/smtp.c
View File

@ -448,9 +448,9 @@
/* Optional lookup tables with the Postfix SMTP client TLS security /* Optional lookup tables with the Postfix SMTP client TLS security
/* policy by next-hop destination; when a non-empty value is specified, /* policy by next-hop destination; when a non-empty value is specified,
/* this overrides the obsolete smtp_tls_per_site parameter. /* this overrides the obsolete smtp_tls_per_site parameter.
/* .IP "\fBsmtp_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR" /* .IP "\fBsmtp_tls_mandatory_protocols (see 'postconf -d' output)\fR"
/* List of SSL/TLS protocols that the Postfix SMTP client will use with /* TLS protocols that the Postfix SMTP client will use with mandatory
/* mandatory TLS encryption. /* TLS encryption.
/* .IP "\fBsmtp_tls_scert_verifydepth (9)\fR" /* .IP "\fBsmtp_tls_scert_verifydepth (9)\fR"
/* The verification depth for remote SMTP server certificates. /* The verification depth for remote SMTP server certificates.
/* .IP "\fBsmtp_tls_secure_cert_match (nexthop, dot-nexthop)\fR" /* .IP "\fBsmtp_tls_secure_cert_match (nexthop, dot-nexthop)\fR"
@ -498,9 +498,9 @@
/* certificate fingerprints. /* certificate fingerprints.
/* .PP /* .PP
/* Available in Postfix version 2.6 and later: /* Available in Postfix version 2.6 and later:
/* .IP "\fBsmtp_tls_protocols (!SSLv2, !SSLv3)\fR" /* .IP "\fBsmtp_tls_protocols (see postconf -d output)\fR"
/* List of TLS protocols that the Postfix SMTP client will exclude or /* TLS protocols that the Postfix SMTP client will use with
/* include with opportunistic TLS encryption. /* opportunistic TLS encryption.
/* .IP "\fBsmtp_tls_ciphers (medium)\fR" /* .IP "\fBsmtp_tls_ciphers (medium)\fR"
/* The minimum TLS cipher grade that the Postfix SMTP client /* The minimum TLS cipher grade that the Postfix SMTP client
/* will use with opportunistic TLS encryption. /* will use with opportunistic TLS encryption.

12
postfix/src/smtpd/smtpd.c
View File

@ -405,9 +405,9 @@
/* .IP "\fBsmtpd_tls_mandatory_exclude_ciphers (empty)\fR" /* .IP "\fBsmtpd_tls_mandatory_exclude_ciphers (empty)\fR"
/* Additional list of ciphers or cipher types to exclude from the /* Additional list of ciphers or cipher types to exclude from the
/* Postfix SMTP server cipher list at mandatory TLS security levels. /* Postfix SMTP server cipher list at mandatory TLS security levels.
/* .IP "\fBsmtpd_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR" /* .IP "\fBsmtpd_tls_mandatory_protocols (see 'postconf -d' output)\fR"
/* The SSL/TLS protocols accepted by the Postfix SMTP server with /* TLS protocols accepted by the Postfix SMTP server with mandatory TLS
/* mandatory TLS encryption. /* encryption.
/* .IP "\fBsmtpd_tls_received_header (no)\fR" /* .IP "\fBsmtpd_tls_received_header (no)\fR"
/* Request that the Postfix SMTP server produces Received: message /* Request that the Postfix SMTP server produces Received: message
/* headers that include information about the protocol and cipher used, /* headers that include information about the protocol and cipher used,
@ -442,9 +442,9 @@
/* \fBcheck_ccert_access\fR and \fBpermit_tls_clientcerts\fR. /* \fBcheck_ccert_access\fR and \fBpermit_tls_clientcerts\fR.
/* .PP /* .PP
/* Available in Postfix version 2.6 and later: /* Available in Postfix version 2.6 and later:
/* .IP "\fBsmtpd_tls_protocols (!SSLv2, !SSLv3)\fR" /* .IP "\fBsmtpd_tls_protocols (see postconf -d output)\fR"
/* List of TLS protocols that the Postfix SMTP server will exclude /* TLS protocols accepted by the Postfix SMTP server with opportunistic
/* or include with opportunistic TLS encryption. /* TLS encryption.
/* .IP "\fBsmtpd_tls_ciphers (medium)\fR" /* .IP "\fBsmtpd_tls_ciphers (medium)\fR"
/* The minimum TLS cipher grade that the Postfix SMTP server /* The minimum TLS cipher grade that the Postfix SMTP server
/* will use with opportunistic TLS encryption. /* will use with opportunistic TLS encryption.

4
postfix/src/tls/tls.h
View File

@ -385,7 +385,7 @@ extern void tls_param_init(void);
#define TLS_SSL_OP_MANAGED_BITS \ #define TLS_SSL_OP_MANAGED_BITS \
(SSL_OP_CIPHER_SERVER_PREFERENCE | TLS_SSL_OP_PROTOMASK(~0)) (SSL_OP_CIPHER_SERVER_PREFERENCE | TLS_SSL_OP_PROTOMASK(~0))
extern int tls_protocol_mask(const char *); extern int tls_proto_mask_lims(const char *, int *, int *);
/* /*
* Cipher grade selection. * Cipher grade selection.
@ -631,7 +631,7 @@ extern char *tls_digest_encode(const unsigned char *, int);
extern char *tls_cert_fprint(X509 *, const char *); extern char *tls_cert_fprint(X509 *, const char *);
extern char *tls_pkey_fprint(X509 *, const char *); extern char *tls_pkey_fprint(X509 *, const char *);
extern char *tls_serverid_digest(TLS_SESS_STATE *, extern char *tls_serverid_digest(TLS_SESS_STATE *,
const TLS_CLIENT_START_PROPS *, long, const char *); const TLS_CLIENT_START_PROPS *, const char *);
/* /*
* tls_certkey.c * tls_certkey.c

18
postfix/src/tls/tls_client.c
View File

@ -865,6 +865,8 @@ TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
{ {
int sts; int sts;
int protomask; int protomask;
int min_proto;
int max_proto;
const char *cipher_list; const char *cipher_list;
SSL_SESSION *session = 0; SSL_SESSION *session = 0;
TLS_SESS_STATE *TLScontext; TLS_SESS_STATE *TLScontext;
@ -888,7 +890,7 @@ TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
* Per-session protocol restrictions must be applied to the SSL connection, * Per-session protocol restrictions must be applied to the SSL connection,
* as restrictions in the global context cannot be cleared. * as restrictions in the global context cannot be cleared.
*/ */
protomask = tls_protocol_mask(props->protocols); protomask = tls_proto_mask_lims(props->protocols, &min_proto, &max_proto);
if (protomask == TLS_PROTOCOL_INVALID) { if (protomask == TLS_PROTOCOL_INVALID) {
/* tls_protocol_mask() logs no warning. */ /* tls_protocol_mask() logs no warning. */
msg_warn("%s: Invalid TLS protocol list \"%s\": aborting TLS session", msg_warn("%s: Invalid TLS protocol list \"%s\": aborting TLS session",
@ -956,12 +958,24 @@ TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
tls_free_context(TLScontext); tls_free_context(TLScontext);
return (0); return (0);
} }
#define CARP_VERSION(which) do { \
if (which##_proto != 0) \
msg_warn("%s: error setting %simum TLS version to: 0x%04x", \
TLScontext->namaddr, #which, which##_proto); \
else \
msg_warn("%s: error clearing %simum TLS version", \
TLScontext->namaddr, #which); \
} while (0)
/* /*
* Apply session protocol restrictions. * Apply session protocol restrictions.
*/ */
if (protomask != 0) if (protomask != 0)
SSL_set_options(TLScontext->con, TLS_SSL_OP_PROTOMASK(protomask)); SSL_set_options(TLScontext->con, TLS_SSL_OP_PROTOMASK(protomask));
if (!SSL_set_min_proto_version(TLScontext->con, min_proto))
CARP_VERSION(min);
if (!SSL_set_max_proto_version(TLScontext->con, max_proto))
CARP_VERSION(max);
/* /*
* When applicable, configure DNS-based or synthetic (fingerprint or * When applicable, configure DNS-based or synthetic (fingerprint or
@ -1038,7 +1052,7 @@ TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
* parameters and append it to the serverid. * parameters and append it to the serverid.
*/ */
TLScontext->serverid = TLScontext->serverid =
tls_serverid_digest(TLScontext, props, protomask, cipher_list); tls_serverid_digest(TLScontext, props, cipher_list);
/* /*
* When authenticating the peer, use 80-bit plus OpenSSL security level * When authenticating the peer, use 80-bit plus OpenSSL security level

7
postfix/src/tls/tls_fprint.c
View File

@ -6,10 +6,9 @@
/* SYNOPSIS /* SYNOPSIS
/* #include <tls.h> /* #include <tls.h>
/* /*
/* char *tls_serverid_digest(TLScontext, props, protomask, ciphers) /* char *tls_serverid_digest(TLScontext, props, ciphers)
/* TLS_SESS_STATE *TLScontext; /* TLS_SESS_STATE *TLScontext;
/* const TLS_CLIENT_START_PROPS *props; /* const TLS_CLIENT_START_PROPS *props;
/* long protomask;
/* const char *ciphers; /* const char *ciphers;
/* /*
/* char *tls_digest_encode(md_buf, md_len) /* char *tls_digest_encode(md_buf, md_len)
@ -187,7 +186,7 @@ static int tls_digest_tlsa(EVP_MD_CTX *mdctx, TLS_TLSA *tlsa)
char *tls_serverid_digest(TLS_SESS_STATE *TLScontext, char *tls_serverid_digest(TLS_SESS_STATE *TLScontext,
const TLS_CLIENT_START_PROPS *props, const TLS_CLIENT_START_PROPS *props,
long protomask, const char *ciphers) const char *ciphers)
{ {
EVP_MD_CTX *mdctx; EVP_MD_CTX *mdctx;
const EVP_MD *md; const EVP_MD *md;
@ -219,7 +218,7 @@ char *tls_serverid_digest(TLS_SESS_STATE *TLScontext,
checkok(EVP_DigestInit_ex(mdctx, md, NULL)); checkok(EVP_DigestInit_ex(mdctx, md, NULL));
digest_string(props->helo ? props->helo : ""); digest_string(props->helo ? props->helo : "");
digest_object(&sslversion); digest_object(&sslversion);
digest_object(&protomask); digest_string(props->protocols);
digest_string(ciphers); digest_string(ciphers);
/* /*

62
postfix/src/tls/tls_misc.c
View File

@ -69,8 +69,10 @@
/* /*
/* void tls_param_init() /* void tls_param_init()
/* /*
/* int tls_protocol_mask(plist) /* int tls_proto_mask_lims(plist, floor, ceiling)
/* const char *plist; /* const char *plist;
/* int *floor;
/* int *ceiling;
/* /*
/* int tls_cipher_grade(name) /* int tls_cipher_grade(name)
/* const char *name; /* const char *name;
@ -157,10 +159,12 @@
/* entering a chroot jail. The "role" parameter must be TLS_ROLE_CLIENT /* entering a chroot jail. The "role" parameter must be TLS_ROLE_CLIENT
/* for clients and TLS_ROLE_SERVER for servers. Any errors are fatal. /* for clients and TLS_ROLE_SERVER for servers. Any errors are fatal.
/* /*
/* tls_protocol_mask() returns a bitmask of excluded protocols, given /* tls_proto_mask_lims() returns a bitmask of excluded protocols, and
/* a list (plist) of protocols to include or (preceded by a '!') exclude. /* and the protocol version floor/ceiling, given a list (plist) of
/* If "plist" contains invalid protocol names, TLS_PROTOCOL_INVALID is /* protocols to include or (preceded by a '!') exclude, or constraints
/* returned and no warning is logged. /* of the form '>=name', '<=name', '>=hexvalue', '<=hexvalue'. If "plist"
/* contains invalid protocol names, TLS_PROTOCOL_INVALID is returned and
/* no warning is logged.
/* /*
/* tls_cipher_grade() converts a case-insensitive cipher grade /* tls_cipher_grade() converts a case-insensitive cipher grade
/* name (high, medium, low, export, null) to the corresponding /* name (high, medium, low, export, null) to the corresponding
@ -315,6 +319,19 @@ static const NAME_CODE protocol_table[] = {
0, TLS_PROTOCOL_INVALID, 0, TLS_PROTOCOL_INVALID,
}; };
/*
* Protocol name => numeric version, for MinProtocol and MaxProtocol
*/
static const NAME_CODE tls_version_table[] = {
"None", 0,
SSL_TXT_SSLV3, SSL3_VERSION,
SSL_TXT_TLSV1, TLS1_VERSION,
SSL_TXT_TLSV1_1, TLS1_1_VERSION,
SSL_TXT_TLSV1_2, TLS1_2_VERSION,
TLS_PROTOCOL_TXT_TLSV1_3, TLS1_3_VERSION,
0, -1,
};
/* /*
* SSL_OP_MUMBLE bug work-around name <=> mask conversion. * SSL_OP_MUMBLE bug work-around name <=> mask conversion.
*/ */
@ -551,9 +568,32 @@ void tls_update_app_logmask(TLS_APPL_STATE *app_ctx, int log_mask)
app_ctx->log_mask = log_mask; app_ctx->log_mask = log_mask;
} }
/* tls_protocol_mask - Bitmask of protocols to exclude */ /* parse_version - parse TLS protocol version name or hex number */
int tls_protocol_mask(const char *plist) static int parse_tls_version(const char *tok, int *version)
{
int code = name_code(tls_version_table, NAME_CODE_FLAG_NONE, tok);
char *_end;
unsigned long ulval;
if (code != -1) {
*version = code;
return (0);
}
errno = 0;
ulval = strtoul(tok, &_end, 16);
if (*_end != 0
|| (ulval == ULONG_MAX && errno == ERANGE)
|| ulval > INT_MAX)
return TLS_PROTOCOL_INVALID;
*version = (int) ulval;
return (0);
}
/* tls_proto_mask_lims - protocols to exclude and floor/ceiling */
int tls_proto_mask_lims(const char *plist, int *floor, int *ceiling)
{ {
char *save; char *save;
char *tok; char *tok;
@ -567,9 +607,15 @@ int tls_protocol_mask(const char *plist)
return (res); \ return (res); \
} while (0) } while (0)
*floor = *ceiling = 0;
save = cp = mystrdup(plist); save = cp = mystrdup(plist);
while ((tok = mystrtok(&cp, CHARS_COMMA_SP ":")) != 0) { while ((tok = mystrtok(&cp, CHARS_COMMA_SP ":")) != 0) {
if (*tok == '!') if (strncmp(tok, ">=", 2) == 0)
code = parse_tls_version(tok + 2, floor);
else if (strncmp(tok, "<=", 2) == 0)
code = parse_tls_version(tok + 2, ceiling);
else if (*tok == '!')
exclude |= code = exclude |= code =
name_code(protocol_table, NAME_CODE_FLAG_NONE, ++tok); name_code(protocol_table, NAME_CODE_FLAG_NONE, ++tok);
else else

8
postfix/src/tls/tls_server.c
View File

@ -342,6 +342,8 @@ TLS_APPL_STATE *tls_server_init(const TLS_SERVER_INIT_PROPS *props)
int scache_timeout; int scache_timeout;
int ticketable = 0; int ticketable = 0;
int protomask; int protomask;
int min_proto;
int max_proto;
TLS_APPL_STATE *app_ctx; TLS_APPL_STATE *app_ctx;
int log_mask; int log_mask;
@ -366,7 +368,7 @@ TLS_APPL_STATE *tls_server_init(const TLS_SERVER_INIT_PROPS *props)
/* /*
* First validate the protocols. If these are invalid, we can't continue. * First validate the protocols. If these are invalid, we can't continue.
*/ */
protomask = tls_protocol_mask(props->protocols); protomask = tls_proto_mask_lims(props->protocols, &min_proto, &max_proto);
if (protomask == TLS_PROTOCOL_INVALID) { if (protomask == TLS_PROTOCOL_INVALID) {
/* tls_protocol_mask() logs no warning. */ /* tls_protocol_mask() logs no warning. */
msg_warn("Invalid TLS protocol list \"%s\": disabling TLS support", msg_warn("Invalid TLS protocol list \"%s\": disabling TLS support",
@ -514,6 +516,10 @@ TLS_APPL_STATE *tls_server_init(const TLS_SERVER_INIT_PROPS *props)
*/ */
if (protomask != 0) if (protomask != 0)
SSL_CTX_set_options(server_ctx, TLS_SSL_OP_PROTOMASK(protomask)); SSL_CTX_set_options(server_ctx, TLS_SSL_OP_PROTOMASK(protomask));
SSL_CTX_set_min_proto_version(server_ctx, min_proto);
SSL_CTX_set_max_proto_version(server_ctx, max_proto);
SSL_CTX_set_min_proto_version(sni_ctx, min_proto);
SSL_CTX_set_max_proto_version(sni_ctx, max_proto);
/* /*
* Some sites may want to give the client less rope. On the other hand, * Some sites may want to give the client less rope. On the other hand,