Prior to running the keymgr, first make sure that existing keys
are present in the new keylist. If not, treat this as an operational
error where the keys are made offline (temporarily), possibly unwanted.
Rename check_recursionquota() to acquire_recursionquota(), and
implement a new function called release_recursionquota() to
reverse the action. It helps with decreasing code duplication.
In two places, after linking the client to the manager's
"recursing-clients" list using the check_recursionquota()
function, the query.c module fails to unlink it on error
paths. Fix the bugs by unlinking the client from the list.
Also make sure that unlinking happens before detaching the
client's handle, as it is the logically correct order, e.g.
in case if it's the last handle and ns__client_reset_cb()
can be called because of the detachment.
The dns_zone_getxfrintime() function fails to lock the zone before
accessing its 'xfrintime' structure member, which can cause a data
race between soa_query() and the statistics channel. Add the missing
locking/unlocking pair, like it's done in numerous other similar
functions.
The 'nodetach' member is a leftover from the times when non-zero
'stale-answer-client-timeout' values were supported, and currently
is always 'false'. Clean up the member and its usage.
Currently, the outgoing UDP sockets have enabled
SO_REUSEADDR (SO_REUSEPORT on BSDs) which allows multiple UDP sockets to
bind to the same address+port. There's one caveat though - only a
single (the last one) socket is going to receive all the incoming
traffic. This in turn could lead to incoming DNS message matching to
invalid dns_dispatch and getting dropped.
Disable setting the SO_REUSEADDR on the outgoing UDP sockets. This
needs to be done explicitly because `uv_udp_open()` silently enables the
option on the socket.
When matching the TCP dispatch responses, we should skip the responses
that do not belong to our TCP connection. This can happen with faulty
upstream server that sends invalid QID back to us.
The dns_dispatch_add() function registers the 'resp' entry in
'disp->mgr->qids' hash table with 'resp->port' being 0, but in
tcp_recv_success(), when looking up an entry in the hash table
after a successfully received data the port is used, so if the
local port was set (i.e. it was not 0) it fails to find the
entry and results in an unexpected error.
Set the 'resp->port' to the given local port value extracted from
'disp->local'.
This commit adds support for timestamps in iso8601 format with timezone
when logging. This is exposed through the iso8601-tzinfo printtime
suboption.
It also makes the new logging format the default for -g output,
hopefully removing the need for custom timestamp parsing in scripts.
This commit nulls all type fields for the clausedef lists that are
declared ancient, and removes the corresponding cfg_type_t and parsing
functions when they are found to be unused after the change.
Static-stub address and addresses from other sources where being
mixed together resulting in static-stub queries going to addresses
not specified in the configuration or alternatively static-stub
addresses being used instead of the real addresses.
As the relaxed memory ordering doesn't ensure any memory
synchronization, it is possible that the increment will succeed even
in the case when it should not - there is a race between
atomic_fetch_sub(..., acq_rel) and atomic_fetch_add(..., relaxed).
Only the result is consistent, but the previous value for both calls
could be same when both calls are executed at the same time.
An exit path in the dns_dispatch_add() function fails to get out of
the RCU critical section when returning early. Add the missing
rcu_read_unlock() call.
This change uses uv_get_total_memory() to get the memory available to
BIND 9 with possible modification by uv_get_constrained_memory() if the
libuv version is recent enough to honour constraints created by
f.e. cgroups.
The OpenBSD doesn't have sysctlbyname(), but sysctl() can be used to
read the number of online/available CPUs by reading following MIB(s):
[CTL_HW, HW_NCPUONLINE] with fallback to [CTL_HW, HW_NCPU].
Cleanup various checks and cleanups that are available on the all
platforms like sysctlbyname() and various related <sys/*.h> headers
that are either defined in POSIX or available on Linux and all BSDs.
Instead of cooking up our own code for getting the number of available
CPUs for named to use, make use of uv_available_parallelism() from
libuv >= 1.44.0.
The dns_dispatch_add() call in the dns_xfrin unit had hardcoded 30
second limit. This meant that any incoming transfer would be stopped in
it didn't finish within 30 seconds limit. Additionally, dns_xfrin
callback was ignoring the return value from dns_dispatch_getnext() when
restarting the reading from the TCP stream; this could cause transfers
to get stuck waiting for a callback that would never come due to the
dns_dispatch having already been shut down.
Call the dns_dispatch_add() without a timeout and properly handle the
result code from the dns_dispatch_getnext().
The dns_dispatch_add() has timeout parameter that could not be 0 (for
not timeout). Modify the dns_dispatch implementation to accept a zero
timeout for cases where the timeouts are undesirable because they are
managed externally.
Query and response log shares the same flags. Move flags logging out of
log_query to share it with log_response. Use buffer instead of snprintf
to fill flags a bit faster.
Signed-off-by: Petr Menšík <pemensik@redhat.com>
Remove answer flag from log, log instead count of records for each
message section. Include EDNS version and few flags of response. Add
also status of result.
Still does not include body of responses rrset.
when the QP cache was adapted from the RBT database, some names
weren't changed. this could be confusing, so let's change them now.
also, we no longer need to include rbt.h.
DNSRPS was the API for a commercial implementation of Response-Policy
Zones that was supposedly better. However, it was never open-sourced
and has only ever been available from a single vendor. This goes against
the principle that the open-source edition of BIND 9 should contain only
features that are generally available and universal.
This commit removes the DNSRPS implementation from BIND 9. It may be
reinstated in the subscription edition if there's enough interest from
customers, but it would have to be rewritten as a plugin (hook) instead
of hard-wiring it again in so many places.
If the operating system UDP queue gets full and the outgoing UDP sending
starts to be delayed, BIND 9 could exhibit memory spikes as it tries to
enqueue all the outgoing UDP messages. As those are not going to be
delivered anyway (as we argued when we stopped enlarging the operating
system send and receive buffers), try to send the UDP messages directly
using `uv_udp_try_send()` and if that fails, drop the outgoing UDP
message.
We currently set SO_INCOMING_CPU incorrectly, and testing by Ondrej
shows that fixing the issue and setting affinities is worse than letting
the kernel schedule threads without constraints. So we should not set
SO_INCOMING_CPU anymore.
The 'all_spilled' local variable in resolver.c:fctx_getaddresses()
is 'true' by default, and only becomes false when there is at least
one successfully found NS address. However, when a 'forward only;'
configuration is used, the code jumps over the part where it looks
for NS addresses and doesn't reset the 'all_spilled' to false, which
results in incorretly increased 'serverquota' statistics variable,
and also in invalid return error code from the function. The result
code error didn't make any differences, because all codes other than
'ISC_R_SUCCESS' or 'DNS_R_WAIT' were treated in the same way, and
the result code was never logged anywhere.
Set the default value of 'all_spilled' to 'false', and only make it
'true' before actually starting to look up NS addresses.
Currently, the isc_work API is overloaded. It runs both the
CPU-intensive operations like DNSSEC validations and long-term tasks
like RPZ processing, CATZ processing, zone file loading/dumping and few
others.
Under specific circumstances, when many large zones are being loaded, or
RPZ zones processed, this stops the CPU-intensive tasks and the DNSSEC
validation is practically stopped until the long-running tasks are
finished.
As this is undesireable, this commit moves the CPU-intensive operations
from the isc_work API to the isc_helper API that only runs fast memory
cleanups now.
Add an extra thread that can be used to offload operations that would
affect latency, but are not long-running tasks; those are handled by
isc_work API.
Each isc_loop now has matching isc_helper thread that also built on top
of uv_loop. In fact, it matches most of the isc_loop functionality, but
only the `isc_helper_run()` asynchronous call is exposed.
When verifying a message in an offloaded thread there is a race with
the worker thread which writes to the same buffer. Clone the message
buffer before offloading.
Remove the use of "port" when configuring query-source(-v6),
transfer-source(-v6), notify-source(-v6), parental-source(-v6),
etc. Remove the use of source ports for parental-agents.
Also remove the deprecated options use-{v4,v6}-udp-ports and
avoid-{v4,v6}udp-ports.
This change allows fallback from an IXFR failure to AXFR when the
reason is DNS_R_TOOMANYRECORDS. This is because this error condition
could be temporary only in an intermediate version of IXFR
transactions and it's possible that the latest version of the zone
doesn't have that condition. In such a case, the secondary would never
be able to update the zone (even if it could) without this fallback.
This fallback behavior is particularly useful with the recently
introduced max-records-per-type and max-types-per-name options:
the primary may not have these limitations and may temporarily
introduce "too many" records, breaking IXFR. If the primary side
subsequently deletes these records, this fallback will help recover
the zone transfer failure automatically; without it, the secondary
side would first need to increase the limit, which requires more
operational overhead and has its own adverse effect.
This change also fixes a minor glitch that DNS_R_TOOMANYRECORDS wasn't
logged in xfrin_fail.
The rcu_xchg_pointer() function can be used outside of a critical
section, and usually must be followed by a synchronize_rcu() or
call_rcu() call to detach from the resource, unless if there are
some guarantees in place because of our own reference counting.
named-checkconf now takes "-n" to ignore "not configured" errors.
This allows named-checkconf to check the syntax of configurations
from other builds which have support for more options.
If the ZSK has lifetime unlimited, the timing metadata "Inactive" and
"Delete" cannot be found and is treated as an error. Fix by allowing
these metadata to not exist.
When a validator is already shut down, val->name becomes NULL. We
need to process and keep the ISC_R_CANCELED or ISC_R_SHUTTINGDOWN
result code before calling validate_async_done(), otherwise, when it
is called with the hardcoded DNS_R_NOVALIDSIG result code, it can
cause an assetion failure when val->name (being NULL) is used in
proveunsecure().
Administrators may wish to constrain the set of cores that BIND 9 runs
on via the 'taskset', 'cpuset' or 'numactl' programs (or equivalent on
other O/S), for example to achieve higher (or more stable) performance
by more closely associating threads with individual NIC rx queues. If
the admin has used taskset, it follows that BIND ought to
automatically use the given number of CPUs rather than the system wide
count.
Co-Authored-By: Ray Bellis <ray@isc.org>
Return partial match from dns_db_find/dns_db_find when requested
to short circuit the closest encloser discover process. Most of the
time this will be the actual closest encloser but may not be when
there yet to be committed / cleaned up versions of the zone with
names below the actual closest encloser.
fctx->state should be read with the lock held.
1559 /*
1560 * Caller must be holding the fctx lock.
1561 */
CID 468796: (#1 of 1): Data race condition (MISSING_LOCK)
1. missing_lock: Accessing fctx->state without holding lock fetchctx.lock.
Elsewhere, fetchctx.state is written to with fetchctx.lock held 2 out of 2 times.
1562 REQUIRE(fctx->state == fetchstate_done);
1563
1564 FCTXTRACE("sendevents");
1565
1566 LOCK(&fctx->lock);
1567
Give prefetches a free pass through the quota so that the cache
entries for popular zones could be updated successfully even if the
quota for is already reached.
Give prefetches a free pass through the quota so that the cache entry
for a popular zone could be updated successfully even if the quota for
it is already reached.
Although the nanual page of malloc_usable_size says:
Although the excess bytes can be over‐written by the application
without ill effects, this is not good programming practice: the
number of excess bytes in an allocation depends on the underlying
implementation.
it looks like the premise is broken with _FORTIFY_SOURCE=3 on newer
systems and it might return a value that causes program to stop with
"buffer overflow" detected from the _FORTIFY_SOURCE. As we do have own
implementation that tracks the allocation size that we can use to track
the allocation size, we can stop relying on this introspection function.
Also the newer manual page for malloc_usable_size changed the NOTES to:
The value returned by malloc_usable_size() may be greater than the
requested size of the allocation because of various internal
implementation details, none of which the programmer should rely on.
This function is intended to only be used for diagnostics and
statistics; writing to the excess memory without first calling
realloc(3) to resize the allocation is not supported. The returned
value is only valid at the time of the call.
Remove usage of both malloc_usable_size() and malloc_size() to be on the
safe size and only use the internal size tracking mechanism when
jemalloc is not available.
This limits the maximum number of received incremental zone
transfer differences for a secondary server. Upon reaching the
confgiured limit, the secondary aborts IXFR and initiates a full
zone transfer (AXFR).
If there is an algorithm rollover and two keys of different algorithm
share the same keytags, then there is a possibility that if we check
that a key matches a specific state, we are checking against the wrong
key.
Fix this by not only checking for matching key id but also key
algorithm.
Some things we no longer want to do when we are in offline-ksk mode.
1. Don't check for inactive and private keys if the key is a KSK.
2. Don't update the TTL of DNSKEY, CDS and CDNSKEY RRset, these come
from the SKR.
With offline-ksk enabled, we don't run the keymgr because the key
timings are determined by the SKR. We do update the key states but
we derive them from the timing metadata.
Then, we can skip a other tasks in offline-ksk mode, like DS checking
at the parent and CDS synchronization, because the CDS and CDNSKEY
RRsets also come from the SKR.
This added source code stores SKR data. It is loosely based on:
https://www.iana.org/dnssec/archive/files/draft-icann-dnssec-keymgmt-01.txt
A SKR contains a list of signed DNSKEY RRsets. Each change in data
should be stored in a separate bundle. So if the RRSIG is refreshed that
means it is stored in the next bundle. Likewise, if there is a new ZSK
pre-published, it is in the next bundle.
In addition (not mentioned in the draft), each bundle may contain
signed CDS and CDNSKEY RRsets.
Each bundle has an inception time. These will determine when we need
to re-sign or re-key the zone.
Add a new configuration option to enable Offline KSK key management.
Offline KSK cannot work with CSK because it splits how keys with the
KSK and ZSK role operate. Therefore, one key cannot have both roles.
Add a configuration check to ensure this.
There are few places where we attach/detach from the dns_xfrin object
while running on a different thread than the zone's assigned thread -
xfrin_xmlrender() in the statschannel and dns_zone_stopxfr() to name the
two places where it happens now. In the rare case, when the incoming
transfer completes (or shuts down) in the brief period between the other
thread attaches and detaches from the dns_xfrin, the isc_timer_destroy()
calls would be called by the last thread calling the xfrin_detach().
In the worst case, it would be this other thread causing assertion
failure. Move the isc_timer_destroy() call to xfrin_end() function
which is always called on the right thread and to match this move
isc_timer_create() to xfrin_start() - although this other change makes
no difference.
The new
isc_log_createandusechannel() function combines following calls:
isc_log_createchannel()
isc_log_usechannel()
calls into a single call that cannot fail and therefore can be used in
places where we know this cannot fail thus simplifying the error
handling.
Remove the complicated mechanism that could be (in theory) used by
external libraries to register new categories and modules with
statically defined lists in <isc/log.h>. This is similar to what we
have done for <isc/result.h> result codes. All the libraries are now
internal to BIND 9, so we don't need to provide a mechanism to register
extra categories and modules.
The isc_log_write1() and isc_log_vwrite1() functions were meant to
de-duplicate the messages sent to the isc_log subsystem. However, they
were never used in an entire code base and the whole mechanism around it
was complicated and very inefficient. Just remove those, there are
better ways to deduplicate syslog messages inside syslog daemons now.
Add isc_logconfig_get() function to get the current logconfig and use
the getter to replace most of the little dancing around setting up
logging in the tools. Thus:
isc_log_create(mctx, &lctx, &logconfig);
isc_log_setcontext(lctx);
dns_log_setcontext(lctx);
...
...use lcfg...
...
isc_log_destroy();
is now only:
logconfig = isc_logconfig_get(lctx);
...use lcfg...
For thread-safety, isc_logconfig_get() should be surrounded by RCU read
lock, but since we never use isc_logconfig_get() in threaded context,
the only place where it is actually used (but not really needed) is
named_log_init().
Instead of juggling different logging context, use one single logging
context that gets initialized in the libisc constructor and destroyed in
the libisc destructor.
The application is still responsible for creating the logging
configuration before using the isc_log API.
This patch is first in the series in a way that it is transparent for
the users of the isc_log API as the isc_log_create() and
isc_log_destroy() are now thin shims that emulate the previous
functionality, but it isc_log_create() will always return internal
isc__lctx pointer and isc_log_destroy() will actually not destroy the
internal isc__lctx context.
Signed-off-by: Ondřej Surý <ondrej@isc.org>
Instead of directly using the result of dirfd() in the unlinkat() call,
check whether the returned file descriptor is actually valid. That
doesn't really change the logic as the unlinkat() would fail with
invalid descriptor anyway, but this is cleaner and will report the right
error returned directly by dirfd() instead of EBADF from unlinkat().
The clang-scan 19 has reported that we are ignoring errno after the call
to rewind(). As we don't really care about the result, just silence the
error, the whole code will be removed in the development version anyway
as it is not needed.
The contexpr introduced in C23 standard makes perfect sense to be used
instead of preprocessor macros - the symbols are kept, etc. Define
ISC_CONSTEXPR to be `constexpr` for C23 and `static const` for the older
C standards. Use the newly introduced macro for the NS_PER_SEC and
friends time constants.
New version of clang (19) has introduced a stricter checks when mixing
integer (and float types) with enums. In this case, we used enum {}
as C17 doesn't have constexpr yet. Change the time conversion constants
to be static const unsigned int instead of enum values.
Check if 'lctx->logconfig' is NULL before using it in isc_log_doit(),
because it's possible that isc_log_destroy() was already called, e.g.
when a 'call_rcu' function wants to log a message during shutdown.
When iterating through the old internal hashmap table, skip all the
nodes that have been already migrated to the new table. We know that
all positions with index less than .hiter are NULL.
When the round robin hashing reorders the map entries on deletion, we
were adjusting the iterator table size only when the reordering was
happening at the internal table boundary. The iterator table size had
to be reduced by one to prevent seeing the entry that resized on
position [0] twice because it migrated to [iter->size - 1] position.
However, the same thing could happen when the same entry migrates a
second time from [iter->size - 1] to [iter->size - 2] position (and so
on) because the check that we are manipulating the entry just in the [0]
position was insufficient. Instead of checking the position [pos == 0],
we now check that the [pos % iter->size == 0], thus ignoring all the
entries that might have moved back to the end of the internal table.
As we now setup the logging very early, parsing the default config would
always print warnings about experimental (and possibly deprecated)
options in the default config. This would even mess with commands like
`named -V` and it is also wrong to warn users about using experimental
options in the default config, because they can't do anything about
this. Add CFG_PCTX_NODEPRECATED and CFG_PCTX_NOEXPERIMENTAL options
that we can pass to cfg parser and silence the early warnings caused by
using experimental options in the default config.
OpenSSL has added support for deterministic ECDSA (RFC 6979) with
version 3.2.
Use it by default as derandomization doesn't pose a risk for DNS
usecases and is allowed by FIPS 186-5.
The fcount_incr() was not increasing counter->count when force was set
to true, but fcount_decr() would try to decrease the counter leading to
underflow and assertion failure. Swap the order of the arguments in the
condition, so the !force is evaluated after incrementing the .count.
Since the enable_fips_mode() now resides inside the isc_tls unit, BIND 9
would fail to compile when FIPS mode was enabled as the DST subsystem
logging functions were missing.
Move the crypto library logging functions from the openssl_link unit to
isc_tls unit and enhance it, so it can now be used from both places
keeping the old dst__openssl_toresult* macros alive.
implement, document, and test the 'max-query-restarts' option
which specifies the query restart limit - the number of times
we can follow CNAMEs before terminating resolution.
MAX_RESTARTS is no longer hard-coded; ns_server_setmaxrestarts()
and dns_client_setmaxrestarts() can now be used to modify the
max-restarts value at runtime. in both cases, the default is 11.
the number of steps that can be followed in a CNAME chain
before terminating the lookup has been reduced from 16 to 11.
(this is a hard-coded value, but will be made configurable later.)
there were cases in resolver.c when queries for NS records were
started without passing a pointer to the parent fetch's query counter;
as a result, the max-recursion-queries quota for those queries started
counting from zero, instead of sharing the limit for the parent fetch,
making the quota ineffective in some cases.
Instead of calling dst_lib_init() and dst_lib_destroy() explicitly by
all the programs, create a separate memory context for the DST subsystem
and use the library constructor and destructor to initialize the DST
internals.
When the SSL object was destroyed, it would invalidate all SSL_SESSION
objects including the cached, but not yet used, TLS session objects.
Properly disassociate the SSL object from the SSL_SESSION before we
store it in the TLS session cache, so we can later destroy it without
invalidating the cached TLS sessions.
Co-authored-by: Ondřej Surý <ondrej@isc.org>
Co-authored-by: Artem Boldariev <artem@isc.org>
Co-authored-by: Aram Sargsyan <aram@isc.org>
When TLS connection (TLSstream) connection was accepted, the children
listening socket was not attached to sock->server and thus it could have
been freed before all the accepted connections were actually closed.
In turn, this would cause us to call isc_tls_free() too soon - causing
cascade errors in pending SSL_read_ex() in the accepted connections.
Properly attach and detach the children listening socket when accepting
and closing the server connections.
Since the support for OpenSSL Engines has been removed, we can now also
remove the checks for OPENSSL_API_LEVEL; The OpenSSL 3.x APIs will be
used when compiling with OpenSSL 3.x, and OpenSSL 1.1.xx APIs will be
used only when OpenSSL 1.1.x is used.
The OpenSSL 1.x Engines support has been deprecated in the OpenSSL 3.x
and is going to be removed. Remove the OpenSSL Engine support in favor
of OpenSSL Providers.
When adding glue to the header, we add header to the wait-free stack to
be cleaned up later which sets wfc_node->next to non-NULL value. When
the actual cleaning happens we would only cleanup the .glue_list, but
since the database isn't locked for the time being, the headers could be
reused while cleaning the existing glue entries, which creates a data
race between database versions.
Revert the code back to use per-database-version hashtable where keys
are the node pointers. This allows each database version to have
independent glue cache table that doesn't affect nodes or headers that
could already "belong" to the future database version.
when searching the cache for a node so that we can delete an
rdataset, it is not necessary to set the 'create' flag. if the
node doesn't exist yet, we then we won't be able to delete
anything from it anyway.
dns_difftuple_create() could only return success, so change
its type to void and clean up all the calls to it.
other functions that only returned a result value because of it
have been cleaned up in the same way.
when a priming query is complete, it's currently logged at
level ISC_LOG_DEBUG(1), regardless of success or failure. we
are now raising it to ISC_LOG_NOTICE in the case of failure.
There isn't a realistic reason to ever use e = 4294967297. Fortunately
its codepath wasn't reachable to users and can be safetly removed.
Keep in mind the `dns_key_generate` header comment was outdated. e = 3
hasn't been used since 2006 so there isn't a reason to panic. The
toggle was the public exponents between 65537 and 4294967297.
The previous work in this area was led by the belief that we might be
calling call_rcu() from within call_rcu() callbacks. After carefully
checking all the current callback, it became evident that this is not
the case and the problem isn't enough rcu_barrier() calls, but something
entirely else.
Call the rcu_barrier() just once as that's enough and the multiple
rcu_barrier() calls will not hide the real problem anymore, so we can
find it.
Since the minimal OpenSSL version is now OpenSSL 1.1.1, remove all kind
of OpenSSL shims and checks for functions that are now always present in
the OpenSSL libraries.
Co-authored-by: Ondřej Surý <ondrej@isc.org>
Co-authored-by: Aydın Mercan <aydin@isc.org>
When putting the 48-bit number into a fixed-size buffer that's exactly 6
bytes, the assertion failure would occur as the 48-bit number is
internally represented as 64-bit number and the code was checking if
there is enough space for `sizeof(val)`. This causes assertion failure
when otherwise valid TSIG signature has a bad timing information.
Specify the size of the argument explicitly, so the 48-bit number
doesn't require 8-byte long buffer.
The fcount_incr() was incorrectly skipping the accounting for the
fetches-per-zone if the force argument was set to true. We want to skip
the accounting only when the fetches-per-zone is completely disabled,
but for individual names we need to do the accounting even if we are
forcing the result to be success.
The PTHREAD_MUTEX_ADAPTIVE_NP and PTHREAD_MUTEX_ERRORCHECK_NP are
usually not defines, but enum values, so simple preprocessor check
doesn't work.
Check for PTHREAD_MUTEX_ADAPTIVE_NP from the autoconf AS_COMPILE_IFELSE
block and define HAVE_PTHREAD_MUTEX_ADAPTIVE_NP. This should enable
adaptive mutex on Linux and FreeBSD.
As PTHREAD_MUTEX_ERRORCHECK actually comes from POSIX and Linux glibc
does define it when compatibility macros are being set, we can just use
PTHREAD_MUTEX_ERRORCHECK instead of PTHREAD_MUTEX_ERRORCHECK_NP.
When automatic-interface-scan is disabled, the route socket was still
being opened. Add new API to connect / disconnect from the route socket
only as needed.
Additionally, move the block that disables periodic interface rescans to
a place where it actually have access to the configuration values.
Previously, the values were being checked before the configuration was
loaded.
Decrementing optlen immediately before calling continue is unneccesary
and inconsistent with the rest of dns_message_pseudosectiontoyaml
and dns_message_pseudosectiontotext. Coverity was also reporting
an impossible false positive overflow of optlen (CID 499061).
4176 } else if (optcode == DNS_OPT_CLIENT_TAG) {
4177 uint16_t id;
4178 ADD_STRING(target, "; CLIENT-TAG:");
4179 if (optlen == 2U) {
4180 id = isc_buffer_getuint16(&optbuf);
4181 snprintf(buf, sizeof(buf), " %u\n", id);
4182 ADD_STRING(target, buf);
CID 499061: (#1 of 1): Overflowed constant (INTEGER_OVERFLOW)
overflow_const: Expression optlen, which is equal to 65534, underflows
the type that receives it, an unsigned integer 16 bits wide.
4183 optlen -= 2;
4184 POST(optlen);
4185 continue;
4186 }
4187 } else if (optcode == DNS_OPT_SERVER_TAG) {
There are use cases for which shorter timeout values make sense.
For example if there is a load balancer which sets RD=1 and
forwards queries to a BIND resolver which is then configured to
talk to backend servers which are not visible in the public NS set.
WIth a shorter timeout value the frontend can give back SERVFAIL
early when backends are not available and the ultimate client will
not penalize the BIND-frontend for non-response.
The period between the most significant nibble of the IPv4 address
and the 2.0.0.2.IP6.ARPA suffix was missing resulting in the wrong
name being checked.
In yaml mode we emit a string for each question and record. Certain
names and data could result in invalid yaml being produced. Use single
quote string for all questions and records. This requires that single
quotes get converted to two quotes within the string.
ALPN are defined as 1*255OCTET in RFC 9460. commatxt_fromtext was not
rejecting invalid inputs produces by missing a level of escaping
which where later caught be dns_rdata_fromwire on reception.
These inputs should have been rejected
svcb in svcb 1 1.svcb alpn=\,abc
svcb1 in svcb 1 1.svcb alpn=a\,\,abc
and generated 00 03 61 62 63 and 01 61 00 02 61 62 63 respectively.
The correct inputs to include commas in the alpn requires double
escaping.
svcb in svcb 1 1.svcb alpn=\\,abc
svcb1 in svcb 1 1.svcb alpn=a\\,\\,abc
and generate 04 2C 61 62 63 and 06 61 2C 2C 61 62 63 respectively.
Due to the maximum query restart limitation a long CNAME chain
it is cut after 16 queries but named still returns NOERROR.
Return SERVFAIL instead and the partial answer.
On a 32 bit machine casting to size_t can still lead to an overflow.
Cast to uint64_t. Also detect all possible negative values for
pages and pagesize to silence warning about possible negative value.
39#if defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
1. tainted_data_return: Called function sysconf(_SC_PHYS_PAGES),
and a possible return value may be less than zero.
2. assign: Assigning: pages = sysconf(_SC_PHYS_PAGES).
40 long pages = sysconf(_SC_PHYS_PAGES);
41 long pagesize = sysconf(_SC_PAGESIZE);
42
3. Condition pages == -1, taking false branch.
4. Condition pagesize == -1, taking false branch.
43 if (pages == -1 || pagesize == -1) {
44 return (0);
45 }
46
5. overflow: The expression (size_t)pages * pagesize might be negative,
but is used in a context that treats it as unsigned.
CID 498034: (#1 of 1): Overflowed return value (INTEGER_OVERFLOW)
6. return_overflow: (size_t)pages * pagesize, which might have underflowed,
is returned from the function.
47 return ((size_t)pages * pagesize);
48#endif /* if defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE) */
The key lifetime should no longer be adjusted if the key is being
retired earlier, for example because a manual rollover was started.
This would falsely be seen as a dnssec-policy lifetime reconfiguration,
and would adjust the retire/removed time again.
This also means we should update the status output, and the next
rollover scheduled is now calculated using (retire-active) instead of
key lifetime.
If dnssec-policy is reconfigured and the key lifetime has changed,
update existing keys with the new lifetime and adjust the retire
and removed timing metadata accordingly.
If the key has no lifetime yet, just initialize the lifetime. It
may be that the retire/removed timing metadata has already been set.
Skip keys which goal is not set to omnipresent. These keys are already
in the progress of retiring, or still unused.
This commit ensures that we are not attempting to accept an expired
TCP connection as we are not interested in any data that could have
been accumulated in its internal buffers. Now we just drop them for
good.
When sending fails, the ns__client_request() would not reset the
connection and continue as nothing is happening. This comes from the
model that we don't care about failed UDP sends because datagrams are
unreliable anyway, but it greatly affects TCP connections with
keep-alive.
The worst case scenario is as follows:
1. the 3-way TCP handshake gets completed
2. the libuv calls the "uv_connection_cb" callback
3. the TCP connection gets queue because of the tcp-clients quota
4. the TCP client sends as many DNS messages as the buffers allow
5. the TCP connection gets dropped by the client due to the timeout
6. the TCP connection gets accepted by the server
7. the data already sent by the client gets read
8. all sending fails immediately because the TCP connection is dead
9. we consume all the data in the buffer in a very tight loop
As it doesn't make sense to trying to process more data on the TCP
connection when the sending is failing, drop the connection immediately
on the first sending error.
As ns_query_init() cannot fail now, remove the error paths, especially
in ns__client_setup() where we now don't have to care what to do with
the connection if setting up the client could fail. It couldn't fail
even before, but now it's formal.
Be more aggressive when throttling the reading - when we can't send the
outgoing TCP synchronously with uv_try_write(), we start throttling the
reading immediately instead of waiting for the send buffers to fill up.
This should not affect behaved clients that read the data from the TCP
on the other end.
Instead of outright refusing to add new RR types to the cache, be a bit
smarter:
1. If the new header type is in our priority list, we always add either
positive or negative entry at the beginning of the list.
2. If the new header type is negative entry, and we are over the limit,
we mark it as ancient immediately, so it gets evicted from the cache
as soon as possible.
3. Otherwise add the new header after the priority headers (or at the
head of the list).
4. If we are over the limit, evict the last entry on the normal header
list.
Add HTTPS, SVCB, SRV, PTR, NAPTR, DNSKEY and TXT records to the list of
the priority types that are put at the beginning of the slabheader list
for faster access and to avoid eviction when there are more types than
the max-types-per-name limit.
Due to omission it was possible to un-throttle a TCP connection
previously throttled due to the peer not reading back data we are
sending.
In particular, that affected DoH code, but it could also affect other
transports (the current or future ones) that pause/resume reading
according to its internal state.
Clear qctx->zversion when clearing qctx->zrdataset et al in
lib/ns/query.c:qctx_freedata. The uncleared pointer could lead to
an assertion failure if zone data needed to be re-saved which could
happen with stale data support enabled.
A different solution in the future might be adopted depending
on feedback and other new information, so it makes sense to mark
these options as EXPERIMENTAL until we have more data.
View matching on an incoming query checks the query's signature,
which can be a CPU-heavy task for a SIG(0)-signed message. Implement
an asynchronous mode of the view matching function which uses the
offloaded signature checking facilities, and use it for the incoming
queries.
Add support for using the offload threadpool to perform message
signature verifications. This should allow check SIG(0)-signed
messages without affecting the worker threads.
This is a tiny helper function which is used only once and can be
replaced with two function calls instead. Removing this makes
supporting asynchronous signature checking less complicated.
In order to protect from a malicious DNS client that sends many
queries with a SIG(0)-signed message, add a quota of simultaneously
running SIG(0) checks.
This protection can only help when named is using more than one worker
threads. For example, if named is running with the '-n 4' option, and
'sig0checks-quota 2;' is used, then named will make sure to not use
more than 2 workers for the SIG(0) signature checks in parallel, thus
leaving the other workers to serve the remaining clients which do not
use SIG(0)-signed messages.
That limitation is going to change when SIG(0) signature checks are
offloaded to "slow" threads in a future commit.
The 'sig0checks-quota-exempt' ACL option can be used to exempt certain
clients from the quota requirements using their IP or network addresses.
The 'sig0checks-quota-maxwait-ms' option is used to define a maximum
amount of time for named to wait for a quota to appear. If during that
time no new quota becomes available, named will answer to the client
with DNS_R_REFUSED.
By default we log a rekey failure on debug level. We should probably
change the log level to error. We make an exception for when the zone
is not loaded yet, it often happens at startup that a rekey is
run before the zone is fully loaded.
when signatures were not added because of too many types already
existing at a node, the diff was not being cleaned up; this led to
a memory leak being reported at shutdown.
Previously, the number of RR types for a single owner name was limited
only by the maximum number of the types (64k). As the data structure
that holds the RR types for the database node is just a linked list, and
there are places where we just walk through the whole list (again and
again), adding a large number of RR types for a single owner named with
would slow down processing of such name (database node).
Add a configurable limit to cap the number of the RR types for a single
owner. This is enforced at the database (rbtdb, qpzone, qpcache) level
and configured with new max-types-per-name configuration option that
can be configured globally, per-view and per-zone.
Previously, the number of RRs in the RRSets were internally unlimited.
As the data structure that holds the RRs is just a linked list, and
there are places where we just walk through all of the RRs, adding an
RRSet with huge number of RRs inside would slow down processing of said
RRSets.
Add a configurable limit to cap the number of the RRs in a single RRSet.
This is enforced at the database (rbtdb, qpzone, qpcache) level and
configured with new max-records-per-type configuration option that can
be configured globally, per-view and per-zone.
The changes in this MR prevent the memory used for sending the outgoing
TCP requests to spike so much. That strictly remove the extra need for
own memory context, and thus since we generally prefer simplicity,
remove the extra memory context with own jemalloc arenas just for the
outgoing send buffers.
The single TCP read can create as much as 64k divided by the minimum
size of the DNS message. This can clog the processing thread and trash
the memory allocator because we need to do as much as ~20k allocations in
a single UV loop tick.
Limit the number of the DNS messages processed in a single UV loop tick
to just single DNS message and limit the number of the outstanding DNS
messages back to 23. This effectively limits the number of pipelined
DNS messages to that number (this is the limit we already had before).
As a single thread can process only one TCP send at the time, we don't
really need a memory pool for the TCP buffers, but it's enough to have
a single per-loop (client manager) static buffer that's being used to
assemble the DNS message and then it gets copied into own sending
buffer.
In the future, this should get optimized by exposing the uv_try API
from the network manager, and first try to send the message directly
and allocate the sending buffer only if we need to send the data
asynchronously.
Constantly allocating, reallocating and deallocating 64K TCP send
buffers by 'ns_client' instances takes too much CPU time.
There is an existing mechanism to reuse the ns_clent_t structure
associated with the handle using 'isc_nmhandle_getdata/_setdata'
(see ns_client_request()), but it doesn't work with TCP, because
every time ns_client_request() is called it gets a new handle even
for the same TCP connection, see the comments in
streamdns_on_complete_dnsmessage().
To solve the problem, we introduce an array of available (unused)
TCP buffers stored in ns_clientmgr_t structure so that a 'client'
working via TCP can have a chance to reuse one (if there is one)
instead of allocating a new one every time.
When TCP client would not read the DNS message sent to them, the TCP
sends inside named would accumulate and cause degradation of the
service. Throttle the reading from the TCP socket when we accumulate
enough DNS data to be sent. Currently this is limited in a way that a
single largest possible DNS message can fit into the buffer.
This commit ensures that an HTTP endpoints set reference is stored in
a socket object associated with an HTTP/2 stream instead of
referencing the global set stored inside a listener.
This helps to prevent an issue like follows:
1. BIND is configured to serve DoH clients;
2. A client is connected and one or more HTTP/2 stream is
created. Internal pointers are now pointing to the data on the
associated HTTP endpoints set;
3. BIND is reconfigured - the new endpoints set object is created and
promoted to all listeners;
4. The old pointers to the HTTP endpoints set data are now invalid.
Instead referencing a global object that is updated on
re-configurations we now store a local reference which prevents the
endpoints set objects to go out of scope prematurely.
It was reported that HTTP/2 session might get closed or even deleted
before all async. processing has been completed.
This commit addresses that: now we are avoiding using the object when
we do not need it or specifically check if the pointers used are not
'NULL' and by ensuring that there is at least one reference to the
session object while we are doing incoming data processing.
This commit makes the code more resilient to such issues in the
future.
Replace the ISC_LIST based deadnodes implementation with isc_queue which
is wait-free and we don't have to acquire neither the tree nor node lock
to append nodes to the queue and the cleaning process can also
copy (splice) the list into a local copy without acquiring the list.
Currently, there's little benefit to this as we need to hold those
locks anyway, but in the future as we move to RCU based implementation,
this will be ready.
To align the cleaning with our event loop based model, remove the
hardcoded count for the node locks and use the number of the event loops
instead. This way, each event loop can have its own cleaning as part of
the process. Use uniform random numbers to spread the nodes evenly
between the buckets (instead of hashing the domain name).
Add an isc_queue implementation that hides the gory details of cds_wfcq
into more neat API. The same caveats as with cds_wfcq.
TODO: Add documentation to the API.
When the cache's memory context was in over memory state when the
cache was flushed it resulted in LRU cleaning removing newly entered
data in the new cache straight away until the old cache had been
destroyed enough to take it out of over memory state. When flushing
the cache create a new memory context for the new db to prevent this.
The `axfr_makedb()` didn't set the loop on the newly created database,
effectively killing delayed cleaning on such database. Move the
database creation into dns_zone API that knows all the gory details of
creating new database suitable for the zone.
The rdataslab.c was full of code like this:
length = raw[0] * 256 + raw[1];
and
count2 = *current2++ * 256;
count2 += *current2++;
Refactor code like this into peek_uint16() and get_uint16 macros
to prevent code repetition and possible mistakes when copy and
pasting the same code over and over.
As a side note for an entertainment of a careful reader of the commit
messages: The byte manipulation was changed from multiplication and
addition to shift with or.
The difference in the assembly looks like this:
MUL and ADD:
movzx eax, BYTE PTR [rdi]
movzx edi, BYTE PTR [rdi+1]
sal eax, 8
or edi, eax
SHIFT and OR:
movzx edi, WORD PTR [rdi]
rol di, 8
movzx edi, di
If the result and/or buffer is then being used after the macro call,
there's more differences in favor of the SHIFT+OR solution.
The detach function declaration in `ISC__REFCOUNT_TRACE_DECL` had an
returned an accidental implicit int. While not allowed since C99, it
became an error by default in GCC 14.
`ISC_REFCOUNT_TRACE_IMPL` and `ISC_REFCOUNT_STATIC_TRACE_IMPL` expanded
into the wrong macros, trying to declare it again with the wrong number
of parameters.
- duplicated question
- duplicated answer
- qtype as an answer
- two question types
- question names
- nsec3 bad owner name
- short record
- short question
- mismatching question class
- bad record owner name
- mismatched class in record
- mismatched KEY class
- OPT wrong owner name
- invalid RRSIG "covers" type
- UPDATE malformed delete type
- TSIG wrong class
- TSIG not the last record
there were TSAN error reports because of conflicting uses of
node->dirty and node->nsec, which were in the same qword.
this could be resolved by separating them, but we could also
make them into atomic values and remove some node locking.
