Previously, the function(s) in the commit subject could fail for various
reasons - mostly allocation failures, or other functions returning
different return code than ISC_R_SUCCESS. Now, the aforementioned
function(s) cannot ever fail and they would always return ISC_R_SUCCESS.
Change the function(s) to return void and remove the extra checks in
the code that uses them.
Previously, the function(s) in the commit subject could fail for various
reasons - mostly allocation failures, or other functions returning
different return code than ISC_R_SUCCESS. Now, the aforementioned
function(s) cannot ever fail and they would always return ISC_R_SUCCESS.
Change the function(s) to return void and remove the extra checks in
the code that uses them.
Previously the socket code would set the TCPv6 maximum segment size to
minimum value to prevent IP fragmentation for TCP. This was not yet
implemented for the network manager.
Implement network manager functions to set and use minimum MTU socket
option and set the TCP_MAXSEG socket option for both IPv4 and IPv6 and
use those to clamp the TCP maximum segment size for TCP, TCPDNS and
TLSDNS layers in the network manager to 1220 bytes, that is 1280 (IPv6
minimum link MTU) minus 40 (IPv6 fixed header) minus 20 (TCP fixed
header)
We already rely on a similar value for UDP to prevent IP fragmentation
and it make sense to use the same value for IPv4 and IPv6 because the
modern networks are required to support IPv6 packet sizes. If there's
need for small TCP segment values, the MTU on the interfaces needs to be
properly configured.
The IPV6_USE_MIN_MTU socket option directs the IP layer to limit the
IPv6 packet size to the minimum required supported MTU from the base
IPv6 specification, i.e. 1280 bytes. Many implementations of TCP
running over IPv6 neglect to check the IPV6_USE_MIN_MTU value when
performing MSS negotiation and when constructing a TCP segment despite
MSS being defined to be the MTU less the IP and TCP header sizes (60
bytes for IPv6). This leads to oversized IPv6 packets being sent
resulting in unintended Path Maximum Transport Unit Discovery (PMTUD)
being performed and to fragmented IPv6 packets being sent.
Add and use a function to set socket option to limit the MTU on IPv6
sockets to the minimum MTU (1280) both for UDP and TCP.
For each algorithm there must be a key performing the KSK and
ZSK rolls. After reading the keys from named.conf check that
each algorithm present has both rolls. CSK implicitly has both
rolls.
bad-ksk-without-zsk.conf only has a ksk defined without a
matching zsk for the same algorithm.
bad-zsk-without-ksk.conf only has a zsk defined without a
matching ksk for the same algorithm.
bad-unpaired-keys.conf has two keys of different algorithms
one ksk only and the other zsk only
When get_dispatch() returns an error code, the dns_request_createraw()
function jumps to the `cleanup` label, which will leave a previous
attachment to the `request` pointer unattached.
Fix the issue by jumping to the `detach` label instead.
The AX_PROG_CC_FOR_BUILD implementation to find a native CC compiler is
slightly better because it uses AC_PROG_CC and AC_PROG_CPP to find the
native compiler instead of just defaulting to `gcc` as AX_CC_FOR_BUILD
does.
AX_PROG_CC_FOR_BUILD also sets BUILD_EXEEXT that we already use in the
Makefile.am for `lib/dns/gen` while AX_CC_FOR_BUILD uses
EXEEXT_FOR_BUILD.
Formerly, the gen.h header contained a compatibility layer between Win32
and POSIX platforms. Since we have already dropped the Win32 build, we
can merged gen.h into gen.c as the header file is not used elsewhere.
The current implementation of isc_queue uses Michael-Scott lock-free
queue that in turn uses hazard pointers. It was discovered that the way
we use the isc_queue, such complicated mechanism isn't really needed,
because most of the time, we either execute the work directly when on
nmthread (in case of UDP) or schedule the work from the matching
nmthreads.
Replace the current implementation of the isc_queue with a simple locked
ISC_LIST. There's a slight improvement - since copying the whole list
is very lightweight - we move the queue into a new list before we start
the processing and locking just for moving the queue and not for every
single item on the list.
NOTE: There's a room for future improvements - since we don't guarantee
the order in which the netievents are processed, we could have two lists
- one unlocked that would be used when scheduling the work from the
matching thread and one locked that would be used from non-matching
thread.
If the dns_request send callback is delayed, the dst API would get
deinitialized and then the detach from the tsig key would cause an
assertion failure.
Shutdown the isc_managers early, and only then dereference the dst
objects when cleaning up the resources used by nsupdate.
The order in which the netievents are processed on the network manager
loop is not guaranteed. Therefore the recv/read callback can come
earlier than the send/write callback.
The dns_request API wasn't ready for this reordering and it was
destroying the dns_request_t object before the send callback has been
called.
Add additional attach/detach in the req_send()/req_senddone() functions
to make sure we don't destroy the dns_request_t while it's still being
references by asynchronous call.
For the reference, the _cancel_lookup() function iterates through
the lookup's queries list and detaches them. In the ideal scenario,
that should be the last reference and the query will be destroyed
after that, but it is also possible that we are still expecting a
callback, which also holds a reference (for example, _cancel_lookup()
could have been called from recv_done(), when send_done() was still
not executed).
The start_udp() and start_tcp() functions are currently designed in
slightly different ways: start_udp() creates a new query attachment
`connectquery`, to be called in the callback function, while
start_tcp() does not, which is a bug, but is hidden by the fact
that when the query is being erroneously destroyed prematurely (before
_cancel_lookup() is called) in the result of that, it also gets
de-listed from the lookup's queries' list, so _cancel_lookup() doesn't
even try to detach it.
For better understanding, here's an illustration of the query's
references count changes, and from where it was changed:
UDP
---
1. _new_query() -> refcount = 1 (initial)
2. start_udp() -> refcount = 2 (lookup->current_query)
3. start_udp() -> refcount = 3 (connectquery)
4. udp_ready() -> refcount = 4 (readquery)
5. udp_ready() -> refcount = 5 (sendquery)
6. udp_ready() -> refcount = 4 (lookup->current_query)
7. udp_ready() -> refcount = 3 (connectquery)
8. send_done() -> refcount = 2 (sendquery)
9. recv_done() -> refcount = 1 (readquery)
10. _cancel_lookup() -> refcount = 0 (initial)
11. the query gets destroyed and removed from `lookup->q`
TCP, fortunate scenario
-----------------------
1. _new_query() -> refcount = 1 (initial)
2. start_tcp() -> refcount = 2 (lookup->current_query)
3. launch_next_query() -> refcount = 3 (readquery)
4. launch_next_query() -> refcount = 4 (sendquery)
5. tcp_connected() -> refcount = 3 (lookup->current_query)
6. tcp_connected() -> refcount = 2 (bug, there was no connectquery)
7. send_done() -> refcount = 1 (sendquery)
8. recv_done() -> refcount = 0 (readquery)
9. the query gets prematurely destroyed and removed from `lookup->q`
10. _cancel_lookup() -> the query is not in `lookup->q`
TCP, unfortunate scenario, revealing the bug
--------------------------------------------
1. _new_query() -> refcount = 1 (initial)
2. start_tcp() -> refcount = 2 (lookup->current_query)
3. launch_next_query() -> refcount = 3 (readquery)
4. launch_next_query() -> refcount = 4 (sendquery)
5. tcp_connected() -> refcount = 3 (lookup->current_query)
6. tcp_connected() -> refcount = 2 (bug, there was no connectquery)
7. recv_done() -> refcount = 1 (readquery)
8. _cancel_lookup() -> refcount = 0 (the query was in `lookup->q`)
9. we hit an assertion here when trying to destroy the query, because
sendhandle is not detached (which is done by send_done()).
10. send_done() -> this never happens
This commit does the following:
1. Add a `connectquery` attachment in start_tcp(), like done in
start_udp().
2. Add missing _cancel_lookup() calls for error scenarios, which
were possibly missing because before fixing the bug, calling
_cancel_lookup() and then calling query_detach() would cause
an assertion.
3. Log a debug message and call isc_nm_cancelread(query->readhandle)
for every query in the lookup from inside the _cancel_lookup()
function, like it is done in _cancel_all().
4. Add a `canceled` property for the query which becomes `true` when
the lookup (and subsequently, its queries) are canceled.
5. Use the `canceled` property in the network manager callbacks to
know that the query was canceled, and act like `eresult` was equal
to `ISC_R_CANCELED`.
There was a missing UNLOCK_LOOKUP in the recv_done() callback when
the operation had been canceled. That omission could result in a
deadlock situation.
BIND unconditionally uses shims for BN_GENCB_new(), BN_GENCB_free(),
and BN_GENCB_get_arg() for all LibreSSL versions and, correctly, for
OpenSSL <1.1.0 versions.
This breaks LibreSSL compilation starting with LibreSSL 3.5.0.
Use autoconf check instead to check whether the family of the functions
are available.
LibreSSL 3.5.0 fails to compile with these shims. We could have just
removed the LibreSSL check from the pre-processor condition, but it
seems that these shims are no longer needed because all the supported
versions of OpenSSL and LibreSSL have those functions.
According to EVP_ENCRYPTINIT(3) manual page in LibreSSL,
EVP_CIPHER_CTX_new() and EVP_CIPHER_CTX_free() first appeared in
OpenSSL 0.9.8b, and have been available since OpenBSD 4.5.
the "zone" clause can be documented using, for instance,
`cfg_test --zonegrammar primary", which prints only
options that are valid in primary zones. this was not
the method being used when generating the named.conf
man page; instead, "zone" was documented with all possible
options, and no zone types at all.
this commit removes "zone" from the generic documentation
and adds include statements in named.conf.rst so that
correct zone grammars will be included in the man page.
when parsing key pairs, if the '=' character fell at max_token
a protective INSIST preventing buffer overrun could be triggered.
Attempt to grow the buffer immediately before the INSIST.
Also removed an unnecessary INSIST on the opening double quote
of key buffer pair.
Resolve "Issue 45110 by ClusterFuzz-External: bind9:dns_master_load_fuzzer: Undefined-shift in soa_get"
Closes#3176
See merge request isc-projects/bind9!5909
By default C promotes short unsigned values to signed int which
leads to undefined behaviour when the value is shifted by too much.
Force unsigned arithmetic to be perform by explicitly casting to a
unsigned type.
The isc__nmsocket_reset() was missing a case for raw TCP sockets (used
by RNDC and DoH) which would case a assertion failure when write timeout
would be triggered.
TCP sockets are now also properly handled in isc__nmsocket_reset().
mem_maybedup() calls isc_mem_allocate() if an mctx is supplied,
but that can no longer fail, so now the only way mem_maybedup()
could return NULL is if it was given a NULL source address by the
caller. this commit adds a REQUIRE to prevent that scenario, and
cleans up all the calling code that previously checked for NULL
return values.
this function is mostly used in rdata tostruct() implementations, so
the documentation for dns_rdata_tostruct() has been updated to
remove 'ISC_R_NOMEMORY' as a possible return value.
