It is possible to have two threads destroying an rbtdb at the same
time when detachnode() executes and removes the last reference to
a node between exiting being set to true for the node and testing
if the references are zero in maybe_free_rbtdb(). Move NODE_UNLOCK()
to after checking if references is zero to prevent detachnode()
changing the reference count too early.
(cherry picked from commit 859d2fdad6)
Since the queries sent towards root and TLD servers are now included in
the count (as a result of the fix for CVE-2020-8616),
"max-recursion-queries" has a higher chance of being exceeded by
non-attack queries. Increase its default value from 75 to 100.
(cherry picked from commit ab0bf49203)
Every DocBook source document can be namespaced (DocBook 5) or
non-namespaced (DocBook 4). The set of XSL stylesheets used for
producing an output document can also be namespaced or non-namespaced.
Namespaced source documents should be used with namespaced stylesheets
and non-namespaced source documents should be used with non-namespaced
stylesheets. However, both stylesheet flavors contain processing rules
which allow them to be used interchangeably for any type of source
document.
Unfortunately, these processing rules became broken in version 1.79.1 of
the stylesheets, which means that non-namespaced source documents can no
longer be correctly transformed into man pages using namespaced
stylesheets and vice versa. This problem was fixed upstream [1], but no
released version of the XSL stylesheets contains that fix yet.
Back in 2016, this problem was reported as RT #43831 and allegedly fixed
in commit 1b8ce3b330. However, that fix
only helped for the non-namespaced version of the stylesheets - while
also breaking man page generation for the namespaced flavor.
Since using namespaced DocBook sources is the current best practice
(DocBook 5), make BIND DocBook sources namespaced again. When using
version 1.79.1 or 1.79.2 of the XSL stylesheets, care must be taken to
ensure namespaced stylesheets are used for generating BIND
documentation.
[1] https://github.com/docbook/xslt10-stylesheets/issues/109
Fallback to TCP when we have already seen a DNS COOKIE response
from the given address and don't have one in this UDP response. This
could be a server that has turned off DNS COOKIE support, a
misconfigured anycast server with partial DNS COOKIE support, or a
spoofed response. Falling back to TCP is the correct behaviour in
all 3 cases.
(cherry picked from commit 0e3b1f5a25)
Make sure pointer checks in unit tests use cmocka assertion macros
dedicated for use with pointers instead of those dedicated for use with
integers or booleans.
(cherry picked from commit f440600126)
cppcheck 2.2 reports the following false positive:
lib/dns/dispatch.c:1220:14: warning: Either the condition 'resp==NULL' is redundant or there is possible null pointer dereference: resp. [nullPointerRedundantCheck]
if (disp != resp->disp) {
^
lib/dns/dispatch.c:1191:11: note: Assuming that condition 'resp==NULL' is not redundant
if (resp == NULL) {
^
lib/dns/dispatch.c:1220:14: note: Null pointer dereference
if (disp != resp->disp) {
^
Apparently this version of cppcheck gets confused about conditional
"goto" statements because line 1220 can never be reached if 'resp' is
NULL.
Move a code block to prevent the above false positive from being
reported without affecting the processing logic.
(cherry picked from commit 0b6216d1c7)
The following compiler warning is emitted for the BACKTRACE_X86STACK
part of lib/isc/backtrace.c:
backtrace.c: In function ‘getrbp’:
backtrace.c:139:1: warning: no return statement in function returning non-void [-Wreturn-type]
While getrbp() stores the value of the RBP register in the RAX register
and thus does attempt to return a value, this is not enough for an
optimizing compiler to always produce the expected result. With -O2,
the following machine code may be generated in isc_backtrace_gettrace():
0x00007ffff7b0ff7a <+10>: mov %rbp,%rax
0x00007ffff7b0ff7d <+13>: mov $0x17,%eax
0x00007ffff7b0ff82 <+18>: retq
The above is equivalent to:
sp = (void **)getrbp();
return (ISC_R_NOTFOUND);
and results in the backtrace never getting printed.
Fix by using an intermediate variable. With this change in place, the
machine code generated with -O2 becomes something like:
0x00007ffff7af5638 <+24>: mov $0x17,%eax
0x00007ffff7af563d <+29>: mov %rbp,%rdx
0x00007ffff7af5640 <+32>: test %rdx,%rdx
0x00007ffff7af5643 <+35>: je 0x7ffff7af56bd <isc_backtrace_gettrace+157>
...
0x00007ffff7af56bd <+157>: retq
(Note that this method of grabbing a stack trace is finicky anyway
because in order for RBP to be relied upon, -fno-omit-stack-frame must
be present among CFLAGS.)
(cherry picked from commit 923c443389)
Some operating systems (e.g. Linux, FreeBSD) provide the
_Unwind_Backtrace() function in libgcc_s.so, which is automatically
linked into any binary using the functions provided by that library. On
OpenBSD, though, _Unwind_Backtrace() is provided by libc++abi.so, which
is not automatically linked into binaries produced by the stock system C
compiler.
Meanwhile, lib/isc/backtrace.c assumes that any GNU-compatible toolchain
allows _Unwind_Backtrace() to be used without any extra provisions in
the build system. This causes build failures on OpenBSD (and possibly
other systems).
Instead of making assumptions, actually check for _Unwind_Backtrace()
support in the toolchain if the backtrace() function is unavailable.
(cherry picked from commit 10d7055791)
DNS_R_NCACHENXRRSET can be return when zones are in transition state
from being unsigned to signed and signed to unsigned. The validation
should be resumed and should result in a insecure answer.
(cherry picked from commit 718e597def)
Stub zones don't make use of AXFR/IXFR for the transfering of zone
data, instead, a single query is issued to the master asking for
their nameserver records (NS).
That works fine unless master is configured with 'minimal-responses'
set to yes, in which case glue records are not provided by master
in the answer with nameservers authoritative for the zone, leaving
stub zones with incomplete databases.
This commit fix this problem in a simple way, when the answer with
the authoritative nameservers is received from master (stub_callback),
for each nameserver listed (save_nsrrset), a A and AAAA records for
the name is verified in the additional section, and if not present
a query is created to resolve the corresponsing missing glue.
A struct 'stub_cb_args' was added to keep relevant information for
performing a query, like TSIG key, udp size, dscp value, etc, this
information is borrowed from, and created within function 'ns_query',
where the resolving of nameserver from master starts.
A new field was added to the struct 'dns_stub', an atomic integer,
namely pending_requests, which is used to keep how many queries are
created when resolving nameserver addresses that were missing in
the glue.
When the value of pending_requests is zero we know we can release
resources, adjust zone timers, dump to zone file, etc.
This commit fix the problems that arose when moving the dns_message_t
object from fetchctx_t to the query structure.
Since the lifetime of query objects are different than that of a
fetchctx and the dns_message_t object held by the query may be being
used by some external module, e.g. validator, even after the query may
have been destroyed, propery handling of the references to the message
were added in this commit to avoid accessing an already destroyed
object.
Specifically, in resquery_response(), a reference to the message is
attached at the beginning of the function and detached at the end, since
a possible call to fctx_cancelquery() would release the dns_message_t
object, and in the next lines of code a call to add_bad() would require
a valid pointer to the same object.
In valcreate() a new reference is attached to the message object, this
ensures that if the corresponding query object is destroyed before the
validator attempts to access it, no invalid pointer access occurs.
In validated() we have to attach a new reference to the message, since
we destroy the validator object at the beginning of the function, and we
need access to the message in the next lines of the same function.
The assertion failure REQUIRE(msg->state == DNS_SECTION_ANY),
caused by calling dns_message_setclass within function resquery_response()
in resolver.c, was happening due to wrong management of dns message_t
objects used to process responses to the queries issued by the resolver.
Before the fix, a resolver's fetch context (fetchctx_t) would hold
a pointer to the message, this same reference would then be used over all
the attempts to resolve the query, trying next server, etc... for this to work
the message object would have it's state reset between each iteration, marking
it as ready for a new processing.
The problem arose in a scenario with many different forwarders configured,
managing the state of the dns_message_t object was lacking better
synchronization, which have led it to a invalid dns_message_t state in
resquery_response().
Instead of adding unnecessarily complex code to synchronize the object,
the dns_message_t object was moved from fetchctx_t structure to the
query structure, where it better belongs to, since each query will produce
a response, this way whenever a new query is created an associated
dns_messate_t is also created.
This commit deals mainly with moving the dns_message_t object from fetchctx_t
to the query structure.
isc_meminfo_totalphys() would return invalid memory size when sysconf()
call would fail, because ((size_t)-1 * -1) is very large number.
(cherry picked from commit 79ca724d46)
Mark Andrews
Tinderbox UserandMichał Kępień
Ondřej SurýandMark Andrews
Petr MensikandMark Andrews
Michal Nowak
Diego Fronza
Witold KręcickiandMichal Nowak
