the value of 'i' in generate could overflow when adding 'step' to
it in the 'for' loop. Use an unsigned int for 'i' which will give
an additional bit and prevent the overflow. The inputs are both
less than 2^31 and and the result will be less than 2^32-1.
The ADB previously used separate reference counters for internal
and external references, plus additional counters for ABD find
and namehook objects, and used all these counters to coordinate
its shutdown process, which was a multi-stage affair involving
a sequence of control events.
It also used a complex interlocking set of static functions for
referencing, deferencing, linking, unlinking, and cleaning up various
internal objects; these functions returned boolean values to their
callers to indicate what additional processing was needed.
The changes in the previous two commits destabilized this fragile
system in a way that was difficult to recover from, so in this commit
we refactor all of it. The dns_adb and dns_adbentry objects now use
conventional attach and detach functions for reference counting, and
the shutdown process is much more straightforward. Instead of
handling shutdown asynchronously, we can just destroy the ADB when
references reach zero
In addition, ADB locking has been simplified. Instead of a
single `find_{name,entry}_and_lock()` function which searches for
a name or entry's hash bucket, locks it, and then searches for the
name or entry in the bucket, we now use one function to find the
bucket (leaving it to the caller to do the locking) and another
find the name or entry. Instead of locking the entire ADB when
modifying hash tables, we now use read-write locks around the
specific hash table. The only remaining need for adb->lock
is when modifying the `whenshutdown` list.
Comments throughout the module have been improved.
Replace adb->{names,entries} and related arrays (indexed by hashed
bucket) with a isc_ht hash tables storing the new struct
adb{name,entry}bucket_t that wraps all the variables that were
originally stored in arrays indexed by "bucket" number stored directly
in the struct dns_adb.
Previously, the task exclusive mode has been used to grow the internal
arrays used to store the named and entries objects. The isc_ht hash
tables are now protected by the isc_rwlock instead and thus the usage of
the task exclusive mode has been removed from the dns_adb.
Co-authored-by: Ondřej Surý <ondrej@isc.org>
the use of "result" as a variable name for a boolean return value
was confusing; all 'result' variables that are not isc_result_t
have been renamed to 'ret'.
The static function print_dns_name() was a duplicate of
dns_name_print(), so it has been replaced with that.
Changed INSIST to REQUIRE where appropriate, and added NULL
initialization for pointer variables.
The use of isc_appctx_t in dns_client was used to wait for
dns_client_startresolve() to finish the processing (the resolve_done()
task callback).
This has been replaced with standard bool+cond+lock combination removing
the need of isc_appctx_t altogether.
Previously, the isc_ht API would always take the key as a literal input
to the hashing function. Change the isc_ht_init() function to take an
'options' argument, in which ISC_HT_CASE_SENSITIVE or _INSENSITIVE can
be specified, to determine whether to use case-sensitive hashing in
isc_hash32() when hashing the key.
Fibonacci hashing was implemented in four separate places (rbt.c,
rbtdb.c, resolver.c, zone.c). This commit combines them into a single
implementation. The hash_32() function is now replaced with
isc_hash_bits32().
In couple places, we have missed INSIST(0) or ISC_UNREACHABLE()
replacement on some branches with UNREACHABLE(). Replace all
ISC_UNREACHABLE() or INSIST(0) calls with UNREACHABLE().
This commit adds support for Strict/Mutual TLS into BIND. It does so
by implementing the backing code for 'hostname' and 'ca-file' options
of the 'tls' statement. The commit also updates the documentation
accordingly.
This commit adds support for keeping CA certificates stores associated
with TLS contexts. The intention is to keep one reusable store per a
set of related TLS contexts.
There is a possible code path of using the uninitialized `bname`
character array while logging an error message.
Initialize the `bname` buffer earlier in the function.
Also, change the initialization routine to use a helper function.
A successful call to `dns_rdata_tostruct()` expects an accompanying
call to `dns_rdata_freestruct()` to free up any memory that could have
been allocated during the first call.
In catz.c there are several places where `dns_rdata_freestruct()` call
is skipped.
Add the missing cleanup routines.
Previously, it was possible to assign a bit of memory space in the
nmhandle to store the client data. This was complicated and prevents
further refactoring of isc_nmhandle_t caching (future work).
Instead of caching the data in the nmhandle, allocate the hot-path
ns_client_t objects from per-thread clientmgr memory context and just
assign it to the isc_nmhandle_t via isc_nmhandle_set().
Some ancient versions of clang reported uninitialized memory use false
positive (see https://bugs.llvm.org/show_bug.cgi?id=14461). Since clang
4.0.1 has been long obsoleted, just remove the workarounds.
Historically, the inline keyword was a strong suggestion to the compiler
that it should inline the function marked inline. As compilers became
better at optimising, this functionality has receded, and using inline
as a suggestion to inline a function is obsolete. The compiler will
happily ignore it and inline something else entirely if it finds that's
a better optimisation.
Therefore, remove all the occurences of the inline keyword with static
functions inside single compilation unit and leave the decision whether
to inline a function or not entirely on the compiler
NOTE: We keep the usage the inline keyword when the purpose is to change
the linkage behaviour.
Previously, the unreachable code paths would have to be tagged with:
INSIST(0);
ISC_UNREACHABLE();
There was also older parts of the code that used comment annotation:
/* NOTREACHED */
Unify the handling of unreachable code paths to just use:
UNREACHABLE();
The UNREACHABLE() macro now asserts when reached and also uses
__builtin_unreachable(); when such builtin is available in the compiler.
Gcc 7+ and Clang 10+ have implemented __attribute__((fallthrough)) which
is explicit version of the /* FALLTHROUGH */ comment we are currently
using.
Add and apply FALLTHROUGH macro that uses the attribute if available,
but does nothing on older compilers.
In one case (lib/dns/zone.c), using the macro revealed that we were
using the /* FALLTHROUGH */ comment in wrong place, remove that comment.
In the GSS-TSIG verification code there was an alarming
variable-length array whose size came off the network, from the
signature in the request. It turned out to be safe, because the caller
had previously checked that the signature had a reasonable size.
However, the safety checks are in the generic TSIG implementation, and
the risky VLA usage was in the GSS-specific code, and they are
separated by the DST indirection layer, so it wasn't immediately
obvious that the risky VLA was in fact safe.
In fact this risky VLA was completely unnecessary, because the GSS
signature can be verified in place without being copied to the stack,
like the message covered by the signature. The `REGION_TO_GBUFFER()`
macro backwardly assigns the region in its left argument to the GSS
buffer in its right argument; this is just a pointer and length
conversion, without copying any data. The `gss_verify_mic()` call uses
both message and signature GSS buffers in a read-only manner.
The clang-format-15 has new option InsertBraces that could add missing
branches around single line statements. Use that to our advantage
without switching to not-yet-released LLVM version to add missing braces
in couple of places.
The fetch can be in the shutting down state when resume_dslookup() is
trying to operate on it.
This is also a security issue, because a malicious actor can set up a
name server which delays certain queries in such a way that the fetch
will time out and shut down, which will cause named to crash.
Add a check to see if the fetch has the shutting down attribute set,
and cancel any further operations on it in such case.
A similar bug had been fixed earlier for the resume_qmin() function,
see [GL #966].
This is an optimisation as we can skip a lot of pointless work when we
know there is a DNAME there.
When we have a partial match and a DNAME above the QNAME, the closest
encloser has the same owner as the DNAME, will have the DNAME bit set
in the type map, and we wouldn't use it as we would return the
DNAME + RRSIG(DNAME) instead.
So there is no point in looking for it nor in attempting to check that
it is valid for the QNAME.
'setup_delegation' depends on 'foundname' being the value returned
by 'dns_rbt_findnode' in the cache and 'find_coveringnsec' was
modifying 'foundname' when a covering NSEC was not found.
When caching glue, we need to ensure that there is no closer
source of truth for the name. If the owner name for the glue
record would be answered by a locally configured zone, do not
cache.
When caching additional and glue data *not* from a forwarder, we must
check that there is no "forward only" clause covering the owner name
that would take precedence. Such names would normally be allowed by
baliwick rules, but a "forward only" zone introduces a new baliwick
scope.
If we are using a fowarder, in addition to checking that names to
be cached are subdomains of the forwarded namespace, we must also
check that there are no subsidiary forwarded namespaces which would
take precedence. To be safe, we don't cache any responses if the
forwarding configuration has changed since the query was sent.
Change the isc_interval_t implementation from separate data type and
separate implementation to be shim implementation on top of isc_time_t.
The distinction between isc_interval_t and isc_time_t has been kept
because they are semantically different - isc_interval_t is relative and
isc_time_t is absolute, but this allows isc_time_t and isc_interval_t to
be freely interchangeable, f.e. this:
isc_time_t *t1;
isc_interval_t *interval;
isc_time_t *t2;
isc_interval_set(interval, isc_time_seconds(t2), isc_time_nanoseconds(t2);;
isc_time_subtract(t1, interval, t2);
isc_interval_set(interval, isc_time_seconds(t2), isc_time_nanoseconds(t2));
to just:
isc_time_t *t1;
isc_interval_t *interval;
isc_time_t *t2;
isc_time_subtract(t1, t2, interval);
without introducing a whole set of new functions.
There were two places where expires argument (absolute isc_time_t value)
was being used. Both places has been converted to use relative interval
argument in preparation of simplification and refactoring of isc_timer
API.
The isc_timer_create() function was a bit conflated. It could have been
used to create a timer and start it at the same time. As there was a
single place where this was done before (see the previous commit for
nta.c), this was cleaned up and the isc_timer_create() function was
changed to only create new timer.
In nta.c, it was the only place where the active timer was created
directly instead of first creating inactive timer and then starting it
with isc_timer_reset().
Change the code to create inactive timer first, so we can refactor the
isc_timer_create() function.
The C17 standard deprecated ATOMIC_VAR_INIT() macro (see [1]). Follow
the suite and remove the ATOMIC_VAR_INIT() usage in favor of simple
assignment of the value as this is what all supported stdatomic.h
implementations do anyway:
* MacOSX.plaform: #define ATOMIC_VAR_INIT(__v) {__v}
* Gcc stdatomic.h: #define ATOMIC_VAR_INIT(VALUE) (VALUE)
1. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1138r0.pdf
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 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.
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.
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 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.
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.
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.
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.
Commit b6d40b3c4e removed most uses of the
'fctx' variable from the rctx_dispfail() function: it is now only needed
by the FCTXTRACE3() macro. However, when --enable-querytrace is not in
effect, that macro evaluates to a list of UNUSED() macros that does not
include "UNUSED(fctx);". This triggers the following compilation
warning when building without --enable-querytrace:
resolver.c: In function 'rctx_dispfail':
resolver.c:7888:21: warning: unused variable 'fctx' [-Wunused-variable]
7888 | fetchctx_t *fctx = rctx->fctx;
| ^~~~
Fix by adding "UNUSED(fctx);" lines to all FCTXTRACE*() macros. This is
safe to do because all of those macros use the 'fctx' local variable, so
there is no danger of introducing new errors caused by use of undeclared
identifiers.
- certain TCP result codes, including ISC_R_EOF and
ISC_R_CONNECTIONRESET, were being mapped to ISC_R_SHUTTINGDOWN
before calling the response handler in tcp_recv_cancelall().
the result codes should be passed through to the response handler
without being changed.
- the response handlers, resquery_response() and req_response(), had
code to return immediately if encountering ISC_R_EOF, but this is
not the correct behavior; that should only happen in the case of
ISC_R_CANCELED when it was the caller that canceled the operation
- ISC_R_CONNECTIONRESET was not being caught in rctx_dispfail().
- removed code in rctx_dispfail() to retry queries without EDNS
when receiving ISC_R_EOF; this is now treated the same as any
other connection failure.
There was a bug in the checking of the "blackhole" ACL in
dns_request_create*(), causing an address to be treated as included
in the ACL if it was explicitly *excluded*. Thus, leaving "blackhole"
unset had no effect, but setting it to "none" would cause any
destination addresses to be rejected for dns_request purposes. This
would cause zone transfer requests and SOA queries to fail, among
other things.
The bug has been fixed, and "blackhole { none; };" was added to the
xfer system test as a regression test.
When a resolver priming attempt completes, the following message is
currently logged:
resolver priming query complete
This message is identical for both successful and failed priming
attempts. Consider the following log excerpts:
- successful priming attempt:
10-Feb-2022 11:33:11.272 all zones loaded
10-Feb-2022 11:33:11.272 running
10-Feb-2022 11:33:19.722 resolver priming query complete
- failed priming attempt:
10-Feb-2022 11:33:29.978 all zones loaded
10-Feb-2022 11:33:29.978 running
10-Feb-2022 11:33:38.432 timed out resolving '_.org/A/IN': 2001:500:9f::42#53
10-Feb-2022 11:33:38.522 timed out resolving './NS/IN': 2001:500:9f::42#53
10-Feb-2022 11:33:42.132 timed out resolving '_.org/A/IN': 2001:500:12::d0d#53
10-Feb-2022 11:33:42.285 timed out resolving './NS/IN': 2001:500:12::d0d#53
10-Feb-2022 11:33:44.685 resolver priming query complete
Include the result of each priming attempt in the relevant log message
to give the administrator better insight into named's resolver priming
process.
Mark Andrews
Evan HuntandOndřej Surý
Artem Boldariev
Aram Sargsyan
Ondřej SurýandOndřej Surý
Tony Finch
