In the current statistics counter implementation, the statistics are
backed by an array of counters, which are updated via atomic operations.
This leads to contention, especially on high core count
machines.
This commit introduces a new isc_statsmulti_t counter that keeps a
separate array per thread. These counters are then aggregated only when
statistics are queried, shifting work off the critical path.
These changes lead to a ~2% improvement in perflab.
A helper macro that returns the current value of a pointer and sets
it to NULL in one expression, useful for transferring ownership in
designated initializers.
The liburcu rcu_cmpxchg_pointer() uses CMM_RELAXED ordering on the CAS
failure path. When a thread loses the CAS and gets another thread's
pointer back, reading fields through that pointer is a data race on
weakly-ordered architectures (ARM, POWER) because the failing load has
no acquire semantics.
Override rcu_cmpxchg_pointer() and rcu_xchg_pointer() to use standard
__atomic builtins with __ATOMIC_ACQ_REL (success) and __ATOMIC_ACQUIRE
(failure) ordering. This fixes the race on all architectures and is
natively visible to ThreadSanitizer.
isc_buffer_init() is given MAX_DNS_MESSAGE_SIZE (65535) as capacity but
only h2->content_length bytes are allocated. This makes the buffer
believe it has more space than actually allocated. A secondary bounds
check (new_bufsize <= h2->content_length) prevents actual overflow, but
the buffer invariant is violated.
Pass h2->content_length as the capacity to match the allocation.
The previous code was incorrectly clearing errno after calling
strtol but before testing the result rather than clearing it and
then calling strtol so that changes to errno can be correctly
determined.
We return DNS_R_NOVALIDSIG if we detected a deadlock. Then in
'validate_async_done()', this result value is used to check if we
need to fall back to insecure. As part of that we create a new fetch
but that fails because of the detected deadlock. This results in a loop
of deadlock detected, fallback to insecure, deadlock detected, ...
Add a new result value, ISC_R_DEADLOCK, and return this instead when
we have detected a deadlock. This will be treated as a generic error,
as there is no special handling for this result value.
Starting from OpenSSL 4 the the X509_get_subject_name() function
returns a 'const' pointer to a name instead of a regular pointer.
Duplicate the name before operating on it, then free it.
The INSIST in isc_radix_insert() checks node->data[RADIX_V4] and
node->node_num[RADIX_V4] twice due to a copy-paste error, never
verifying the RADIX_V6 fields.
Fix the second pair to check RADIX_V6.
Add a REQUIRE(isc_loop() == loop) assertion to isc_work_enqueue()
to strictly enforce that work is enqueued from the loop it is
assigned to. This loudly prohibits cross-thread queue manipulation
before it inevitably turns into a concurrency debugging nightmare.
Use reference counting for isc_histomulti module so that it's
possible to attach/detach to/from the objects when used in the
statistics channel in the coming commits.
NSEC3 hashes are required to fit within a single DNS label. Since there
are 5 bits per label byte without pad characters, the maximum hash size
is floor(63*5/8) (39 bytes).
This patch enforces this maximum length for unknown algorithms, while
strictly enforcing the exact expected digest length for known algorithms
like SHA-1.
For Linux >= 6.8:
Since 2023, Linux has introduced a change to the IP_LOCAL_PORT_RANGE
socket option that eliminates the need for the random window
shifting (implemented as a fallback in the next commit).
By setting IP_LOCAL_PORT_RANGE option, we tell the kernel to use better
approach to the source port selection.
For Linux << 6.8:
This implement selecting port by random shifting range leveraging the
IP_LOCAL_PORT_RANGE socket option. The network manager is initialized
with the ephemeral port range (on startup and on reconfig) and then for
every outgoing TCP connection, we define a custom port range (1000
ports) and then randomly shift the custom range within the system range.
This helps the kernel to reduce the search space to the custom window
between <random_offset, random_offset + 1000>.
Reference:
https://blog.cloudflare.com/linux-transport-protocol-port-selection-performance/#kernel
Since 2015, Linux has introduced a new socket option to overcome TCP
limitations: When an application needs to force a source IP on an active
TCP socket it has to use bind(IP, port=x). As most applications do not
want to deal with already used ports, x is often set to 0, meaning the
kernel is in charge to find an available port. But kernel does not know
yet if this socket is going to be a listener or be connected. This
IP_BIND_ADDRESS_NO_PORT socket option ask the kernel to ignore the 0
port provided by application in bind(IP, port=0) and only remember the
given IP address. The port will be automatically chosen at connect()
time, in a way that allows sharing a source port as long as the 4-tuples
are unique.
Enable IP_BIND_ADDRESS_NO_PORT on the outgoing TCP sockets to overcome
this TCP limitation.
A lingering `sizeof` from the prototype era of !11094 caused the
key-wipe in `isc_hmac_key_destroy` to use `sizeof(key->len)` instead of
`key->len` for the length argument of `isc_safe_memwipe`.
This results in a buffer overflow of zero bytes in HMAC keys that are
less than 4 bytes. As such, the overflow can only be visibile in keys
that are less than 32-bits, which is beyond broken and creating such
keys are only possible in testing.
Therefore, this change is *not* a security fix since the conditions are
never reachable in any imaginable deployment scenario.
Builds that use OpenSSL >=3.0 are unaffected as the `sizeof` was only
remaining in pre-3.0 builds.
This is a bit of a namespace convention violation but it fits the spirit of
this header since it is exposing OpenSSL-isms to others.
Further work is needed to make sure the exposed EVP_MD isn't needed
anymore.
Using `EVP_SIGNATURE` explicit algoritms for signatures have been added
in OpenSSL 3.4 and so is skipped for the initial OpenSSL version
specific code splitting.
Using `EVP_SIGNATURE` explicit algoritms for signatures have been added
in OpenSSL 3.4 and so is skipped for the initial OpenSSL version
specific code splitting.
While being the best place at the time, the tlserr2result doesn't belong
inside TLS code since it is generic to OpenSSL and mostly used in the
dst interface. The newly created ossl_wrap interface is the idea place
for flushing the OpenSSL thread error queue.
Instead of the `EVP_MD_CTX` based functions, use either the new
`EVP_MAC` or the old `HMAC_CTX` based functions.
`EVP_MAC` is the recommended way using using MAC functions in post-3.0
while `HMAC_CTX` is used internally by `EVP_MD_CTX`, making the latter
redundant.
Get rid of the OpenSSL-isms that plague the codebase where the hash type
is `EVP_MD *`
By using a proper enum, alongside the cleanup, we also get the ability
to use constants for known hash sizes instead of having a function call
every time.
`EVP_MD_CTX_get0_md` has been removed instead of being adapted since it
wasn't used anymore.
Dealing with OpenSSL has been rapidly turning into an unwieldy situation
as post-3.0 changes turn the library into a different beast.
Start treating pre and post-3.0 versions differently for easier
maintenance.
This adds the following enum isc_one_or_more and isc_zero_or_more
which specify if one or more or zeror or more bytes are required
when reading the unbounded base64 / hex encoded data.
C23 now has qualifier preserving standard functions for strchr,
bsearch, strpbrk, strrchr, strstr, memchr. There where a few places
where the return value was not assigned to a const qualified pointer.
These have been fixed.
While building on uclibc this error is thrown:
In file included from ./include/dns/log.h:20,
from callbacks.c:19:
../../lib/isc/include/isc/log.h:141:9: error: unknown type name ‘off_t’
141 | off_t maximum_size;
| ^~~~~
This is due to missing include unistd.h, so let's add it on top of
isc/log.h
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
When the CDS/CDNSKEY RRset gets updated, schedule a NOTIFY(CDS) to be
sent to the parental agent. The parental agent is published in the
parent zone as a DSYNC RRset, so first we need to figure out the
parent owner name. This is done by finding the zonecut (querying for
NS RRset until we find a postive answer).
In nsfetch_dsync, we then schedule a zone fetch for the DSYNC record
at <child-labels>._dsync.<parent-labels>. Then we queue the notify
for each target in the DSYNC records that matches the NOTIFY scheme
and CDS RRtype.
Document the way `__attribute__((__constructor__))` and
`__attribute__((__destructor__))` must be used in BIND9 libraries in
order to avoid unexpected behaviors with other third-party libraries.
CLEANUP is a macro similar to CHECK but unconditional, jumping
to cleanup even if the result is ISC_R_SUCCESS. It is now used
in place of DST_RET, CLEANUP_WITH, and CHECK(<non-success constant>).
previously, there were over 40 separate definitions of CHECK macros, of
which most used "goto cleanup", and the rest "goto failure" or "goto
out". there were another 10 definitions of RETERR, of which most were
identical to CHECK, but some simply returned a result code instead of
jumping to a cleanup label.
this has now been standardized throughout the code base: RETERR is for
returning an error code in the case of an error, and CHECK is for jumping
to a cleanup tag, which is now always called "cleanup". both macros are
defined in isc/util.h.
Instead of just crashing when memory allocation fails, also print a
message saying "Out of memory!", the size of the allocation that failed,
total allocated memory from all memory contexts and value of errno.
Maintain the relationship between the parent and child fetch and when
creating a new child fetch, properly check the resolution loops that
would lead to a new fetch would join one of the parent's fetch contexts.
Restore usage of malloc_usable_size()/malloc_size(), but this time only
for memory accounting and statistics purposes. This should reduce the
memory footprint in case of compilation without jemalloc as we don't
have to keep track of the allocated memory size ourselves.
