The lame-ttl cache is implemented in ADB as per-server locked
linked-list "indexed" with <qname,qtype>. This list has to be walked
every time there's a new query or new record added into the lame cache.
Determined attacker can use this to degrade performance of the resolver.
Resolver testing has shown that disabling the lame cache has little
impact on the resolver performance and it's a minimal viable defense
against this kind of attack.
When using 'nsec3param' in 'dnssec-policy' and no specific parameters
are provided, default to zero additional iterations and no salt, as
recommended by draft-ietf-dnsop-nsec3-guidance.
The ReferenceRole class is only available in Sphinx >= 2.0.0, which
makes building BIND 9 documentation impossible with older Sphinx
versions:
Running Sphinx v1.7.6
Configuration error:
There is a programable error in your configuration file:
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/sphinx/config.py", line 161, in __init__
execfile_(filename, config)
File "/usr/lib/python3.6/site-packages/sphinx/util/pycompat.py", line 150, in execfile_
exec_(code, _globals)
File "conf.py", line 21, in <module>
from sphinx.util.docutils import ReferenceRole
ImportError: cannot import name 'ReferenceRole'
Work around the problem by defining a stub version of the ReferenceRole
class if the latter cannot be imported. This allows documentation
(without GitLab hyperlinks in release notes) to be built with older
Sphinx versions.
The documentation and feature-test were using '--with-idn' but the
configure script doesn't recognize this option. The correct option to
enable IDN support is '--with-libidn2'.
We have to mention that every option within a "tls" clause has
defaults out of our control as some platforms have means for defining
encryption policies globally for any application on the system.
In order to comply with these policies, we have not to modify TLS
contexts settings, unless we have to do so according to the options
specified within "tls" clauses.
This commit adds the ability to enable or disable stateless TLS
session resumption tickets (see RFC5077). Having this ability is
twofold.
Firstly, these tickets are encrypted by the server, and the algorithm
might be weaker than the algorithm negotiated during the TLS session
establishment (it is in general the case for TLSv1.2, but the generic
principle applies to TLSv1.3 as well, despite it having better ciphers
for session tickets). Thus, they might compromise Perfect Forward
Secrecy.
Secondly, disabling it might be necessary if the same TLS key/cert
pair is supposed to be used by multiple servers to achieve, e.g., load
balancing because the session ticket by default gets generated in
runtime, while to achieve successful session resumption ability, in
this case, would have required using a shared key.
The proper alternative to having the ability to disable stateless TLS
session resumption tickets is to implement a proper session tickets
key rollover mechanism so that key rotation might be performed
often (e.g. once an hour) to not compromise forward secrecy while
retaining the associated performance benefits. That is much more work,
though. On the other hand, having the ability to disable session
tickets allows having a deployable configuration right now in the
cases when either forward secrecy is wanted or sharing the TLS
key/cert pair between multiple servers is needed (or both).
This commit adds support for enforcing the preference of server
ciphers over the client ones. This way, the server attains control
over the ciphers priority and, thus, can choose more strong cyphers
when a client prioritises less strong ciphers over the more strong
ones, which is beneficial when trying to achieve Perfect Forward
Secrecy.
This commit adds support for setting TLS cipher list string in the
format specified in the OpenSSL
documentation (https://www.openssl.org/docs/man1.1.1/man1/ciphers.html).
The syntax of the cipher list is verified so that specifying the wrong
string will prevent the configuration from being loaded.
This commit adds support for loading DH-parameters (Diffie-Hellman
parameters) via the new "dhparam-file" option within "tls" clause. In
particular, Diffie-Hellman parameters are needed to enable the range
of forward-secrecy enabled cyphers for TLSv1.2, which are getting
silently disabled otherwise.
This commit adds the ability to specify allowed TLS protocols versions
within the "tls" clause. If an unsupported TLS protocol version is
specified in a file, the configuration file will not pass
verification.
Also, this commit adds strict checks for "tls" clauses verification,
in particular:
- it ensures that loading configuration files containing duplicated
"tls" clauses is not allowed;
- it ensures that loading configuration files containing "tls" clauses
missing "cert-file" or "key-file" is not allowed;
- it ensures that loading configuration files containing "tls" clauses
named as "ephemeral" or "none" is not allowed.
"cache-file" was already documented as intended for testing
purposes only and not to be used, so we can remove it without
waiting. this commit marks the option as "ancient", and
removes all the documentation and implementing code, including
dns_cache_setfilename() and dns_cache_dump().
it also removes the documentation for the '-x cachefile`
parameter to named, which had already been removed, but the man
page was not updated at the time.
Address the following warnings reported by PyLint 2.10.2:
************* Module conf
doc/arm/conf.py:90:10: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/arm/conf.py:92:12: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/arm/conf.py:93:9: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/arm/conf.py:143:31: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/man/conf.py:33:10: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/man/conf.py:38:12: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
doc/man/conf.py:39:9: W1406: The u prefix for strings is no longer necessary in Python >=3.0 (redundant-u-string-prefix)
Discourage the single source port on general level and document that the
source port cannot be same as the listening port. This applies to
query-source, transfer-source, notify-source, parental-source, and their
respective IPv6 counterparts.
The native PKCS#11 support has been removed in favour of better
maintained, more performance and easier to use OpenSSL PKCS#11 engine
from the OpenSC project.
Document that the interval on new RRSIG records is randomally
chosen between the limits specified by sig-validity-interval.
document the operatations when this occurs.
This commit adds the code (and some tests) which allows verifying
validity of HTTP paths both in incoming HTTP requests and in BIND's
configuration file.
When backporting the Don't Fragment UDP socket option, it was noticed
that the edns-udp-size probing uses 1432 as one of the values to be
probed and the documentation would be recommending 1400 as the safe
value. As the safe value can be from the 1400-1500 interval, the
documentation has been changed to match the probed value, so we do not
skip it.
Expand the description of mirror zones in the ARM by adding a brief
discussion of how the validation process works for AXFR and IXFR. Move
the paragraph mentioning the "file" option higher up. Apply minor
stylistic and whitespace-related tweaks to the relevant section of the
ARM.
Apply minor stylistical and whitespace-related tweaks to the
descriptions of the "tcp-receive-buffer", "udp-receive-buffer",
"tcp-send-buffer", and "udp-send-buffer" options in the ARM.
The ARM contains typos in the names of the following two options:
- "tcp-receive-buffer"
- "udp-receive-buffer"
Fix the ARM so that it contains proper option names.
