Willy Tarreau [Mon, 25 May 2026 16:23:30 +0000 (18:23 +0200)]
MEDIUM: h1: use ha_random64_pair_hashed() for the WebSocket key
Instead of using two consecutive calls to ha_random64(), let's use the
cleaner and safer ha_random64_pair_hashed(). This way the internal
PRNG state will not leak into the emitted headers.
Willy Tarreau [Mon, 25 May 2026 15:56:01 +0000 (17:56 +0200)]
MEDIUM: tools: use the hashed random pair for UUID generation
The UUID generation used to emit the internal PRNG state, which allows
to predict previous and next ones, or disclose the internal PRNG state.
While not critical, it may eventually become an issue.
This patch uses the new ha_random64_pair_hashed() function that returns
a pair of u64 that are hashed from the internal PRNG state. It's almost
twice as fast on 20 threads (14.1M UUID/s vs 7.8M/s).
Willy Tarreau [Mon, 25 May 2026 16:20:29 +0000 (18:20 +0200)]
MEDIUM: init: fall back to ha_random64_pair_hashed() for the cluster secret
The cluster secret, when SSL is not working, used to involve a mix of
calls to ha_random64() and random() to mask the bits that we didn't want
to see leaked. Let's now simply fall back to ha_random64_pair_hashed()
that does a much better job.
Willy Tarreau [Mon, 25 May 2026 15:30:58 +0000 (17:30 +0200)]
MINOR: tools: provide a function to generate a hashed random pair
A lot of places call two ha_random64() in a row to generate a 128-bit
random. While it's now safe against linear analysis thanks to the XXH64
call, it's still particularly expensive due to the lock.
Here we introduce a new function ha_random64_pair_hashed(), that feeds
two uint64_t with a hash of the PRNG's internal state, and make it
advance. This will cut in half the number of calls to ha_random64()
and should recover a part of the performance lost in the lock. For
now it's not used.
Willy Tarreau [Mon, 25 May 2026 15:30:58 +0000 (17:30 +0200)]
BUG/MEDIUM: tools: insert an XXH64 layer on the PRNG output
Consuming randoms in pairs directly exposes the internal PRNG's state
on moderately idle system. It can allow to predict next (or previous)
UUIDs, QUIC retry tokens, and WS keys for example. Let's insert an XXH64
call on the ha_random64() output to avoid this. We expand the boot seed
as the secret at boot, and use now_ns as the seed for each call. The
original ha_random64() function was renamed to ha_random64_internal()
for use cases where it's not a problem to directly use the internal
state.
The performance loss is only measurable when single-threaded. It drops
from 7.32M UUID per second to 7.16M. Above that there is no longer any
difference due to the DWCAS loop which reaches up to 98.5% CPU at 20
threads.
This will need to be backported to stable releases after a period of
observation.
Willy Tarreau [Tue, 26 May 2026 07:36:12 +0000 (09:36 +0200)]
BUG/MINOR: addons/51d: NUL-terminate headers before passing them to Trie API
_51d_set_device_offsets() passes ctx.value.ptr directly to
fiftyoneDegreesGetDeviceOffset() which expects a null-terminated string.
Let's copy it through the trash first, to avoid possibly surronding
garbage.
Willy Tarreau [Tue, 26 May 2026 07:30:12 +0000 (09:30 +0200)]
BUG/MINOR: resolvers: switch to a better PRNG for query IDs
The PRNG used by the DNS currently is easily predictable once an
observer can collect a few consecutive IDs from the same thread, since
it's a 32-bit xorshift reduced to 16 bits output. Let's switch it to
ha_random32() instead.
This should be backported, however on older releases the ha_random32()
cost is higher due to the lock involved.
Willy Tarreau [Tue, 26 May 2026 07:23:48 +0000 (09:23 +0200)]
BUG/MINOR: ssl-hello: make use of the null-terminated servername
In ssl_sock_switchctx_cbk(), the servername is copied into the trash
and null-terminated, but later in the call to strncpy() it's still used
as-is, so anything that follows it will be copied as well, which is not
really expected. Let's make the servername point to the trash after
sanitizing it, like ssl_sock_switchcbk_wolfSSL_cbk() does.
This can be backported to 2.6 since it was introduced with commit a996763619 ("BUG/MINOR: ssl: Store client SNI in SSL context in case
of ClientHello error").
Willy Tarreau [Tue, 26 May 2026 07:06:03 +0000 (09:06 +0200)]
BUG/MINOR: payload: fix the handshake length bounds check smp_client_hello_parse()
After reading the handshake length, which is covered by the previous
4 bytes check, the size was not subtracted before being compared to the
retrieved handshake length, making it possible to accept a handshake
that claims to be 4 bytes larger than it really is. Similarly, a few
lines later, data[34] is accessed without checking that it is present,
because the test is made on the second hs_len, which doesn't guarantee
that the data are there.
This fix adds both tests. It can be backported to all stable versions
as it was introduced in 1.6 with commit bb2acf589f ("MINOR: payload:
add support for tls session ticket ext").
Willy Tarreau [Tue, 26 May 2026 06:54:15 +0000 (08:54 +0200)]
BUG/MINOR: base64: return empty string for empty input in base64dec()
Right now no special case is made of size zero and the parser assumes
that it can read the last two chars, which do not exist in this case.
Let's check for this empty string situation and return zero (empty) as
well.
Willy Tarreau [Tue, 26 May 2026 06:47:11 +0000 (08:47 +0200)]
BUG/MINOR: http-ext: always check remaining data when reading rfc7239 nodeport
http_7239_extract_nodeport() reads the first byte of the passed string
but the caller doesn't check that it's not empty, which can happen if
passed as 'host="127.0.0.1:"'. In that case the function would read and
return garbage that is present in the buffer after the colon. Let's just
check the remaining length before reading.
This can be backported to 2.8 as it was introduced with commit b2bb9257d2
("MINOR: proxy/http_ext: introduce proxy forwarded option").
Willy Tarreau [Tue, 26 May 2026 06:36:36 +0000 (08:36 +0200)]
BUG/MEDIUM: acme: protect against risk of null-deref on connection failure
7 ACME state handlers iterate over hc->res.hdrs, but they can be called
after an error was detected, and the HTTP client will leave res.hdrs NULL
on connection errors before headers are received. Let's check this inside
the loop, like the chkorder handler already does.
Most of them, if not all, need to be backported to 3.2.
Willy Tarreau [Tue, 26 May 2026 06:28:33 +0000 (08:28 +0200)]
BUG/MINOR: http-fetch: check against the whole token in get_http_auth()
In 1.4, Basic authentication support was added by commit f9423ae43a
("[MINOR] acl: add http_auth and http_auth_group"). Interestingly,
a mistake there consisted in taking the length of the comparison from
the input token, so "b" matches "Basic". It was later propagated to
Bearer in 2.5 with commit f5dd337b12 ("MINOR: http:
Add http_auth_bearer sample fetch"). Let's just compare the entire
tokens.
Willy Tarreau [Tue, 26 May 2026 06:24:04 +0000 (08:24 +0200)]
BUG/MINOR: sample: request an extra output byte for the url_dec converter
A dynamic chunk size is now being allocated for output since commit dfc4085413 ("MEDIUM: sample: Get chunks with a size dependent on input
data when necessary"). However this one missed the need for the trailing
zero when specifying the size, let's add it.
Willy Tarreau [Fri, 22 May 2026 06:47:39 +0000 (06:47 +0000)]
BUG/MINOR: resolvers: relax size checks in authority record parsing
Both boundary checks in the authority record parsing loop of
resolv_validate_dns_response() use >= bufend where they should use
> bufend, causing valid DNS responses with exactly enough bytes to be
rejected as invalid.
The first one, "reader + offset + 10 >= bufend" is too strict since it
prevents 10-byte responses from being accepted as valid while they
are. The second one, "reader + len >= bufend" has the same issue, when
exactly len bytes remain, the check rejects it even though dns_max_name()
already validated it. It may be backported though it is unlikely to ever
be noticed.
Willy Tarreau [Sun, 24 May 2026 19:52:54 +0000 (21:52 +0200)]
BUG/MINOR: cache: also recognize directives in the form "token="
The caching RFC (9111, but was present since 2616) indicate that
cache-control supports both the "token" and "token=..." forms and that
consumers are supposed to recognize both. In addition, "private=..." is
explicitly mentioned, so servers could very well emit it. However,
haproxy only recognizes the short form without argument, except for
"no-cache" where it also supports it followed by the beginning of a
set-cookie argument. Thus it could miss "private=" or "no-store=".
Let's refine the checks. Now we explicitly recognize the form
no-cache="set-cookie", and all variants of "token" or "token=" as
identical to disable caching. It will more reliably catch such edge
cases and make sure we never cache a response marked like this.
This should be backported, at least to the latest LTS (3.2), maybe
further after some observation.
Willy Tarreau [Sun, 24 May 2026 16:48:52 +0000 (18:48 +0200)]
BUG/MEDIUM: cache: always verify the primary hash in get_secondary_entry()
When checking for secondary entries, the tree is walked within duplicates
of the primary key, only indexed on the first 32 bits, which means that
in case of hash collision, we could start looking for an object and
switch to another one while visiting secondaries. In order to avoid this
we simply need to always check the full primary hash of the entry that
was found.
Willy Tarreau [Sun, 24 May 2026 17:58:52 +0000 (19:58 +0200)]
BUG/MEDIUM: h1: limit status codes to 3 digits by default
By default, HTTP/1 status codes are not limited in the parser. However,
the value is stored in a 16-bit field, meaning that it may be truncated
if too large. Let's just restrict to 3-digits by default, and permit to
relax the check when accept-unsafe-violations is set, provided that the
value still fits in 16 bits.
Willy Tarreau [Sun, 24 May 2026 11:59:21 +0000 (13:59 +0200)]
BUG/MEDIUM: h1: drop headers whose names contain invalid chars
Originally with "option accept-invalid-http-request", we couldn't really
edit the request on the fly to remove offending headers. But since we
have HTX and the headers are indexed one at a time, it has become
trivial. A non-negligible number of violations are conditioned by the
now renamed "option accept-unsafe-violations-in-http-request", and a
controversial one could definitely be reporting and passing invalid
header names containing control chars or spaces. The option was placed
so as not to block requests/responses containing them, but there's no
point in passing them to the other side. Most of the time it will be
totally harmless since the other side will reject them. But in case
haproxy is placed in front of a non-compliant server, it would fail
to protect it.
This patch implements a name check for all headers when a parsing
error was detected. It's cheap enough (especially since only done
after an error), and will skip the header if its name is invalid.
This may also remove some possibilities of confusion in logs, or
when encoding headers names for example.
This should be backported at least till the latest LTS.
Willy Tarreau [Tue, 26 May 2026 11:11:35 +0000 (13:11 +0200)]
MINOR: haterm: do not emit a warning when not using SSL
Latest commit 04811943b5 ("MINOR: haterm: enable h3 for TCP bindings")
produces a warning when SSL is not enabled due to the addition of
expose-experimental-directives. Let's condition it to the use of SSL.
Willy Tarreau [Mon, 25 May 2026 18:43:38 +0000 (20:43 +0200)]
BUG/MINOR: haterm: fix the random suffix multiplication
Passing a size or anything with suffix "r" is supposed to apply a
random factor form 0 to 1. However due to the replacement of random()
with ha_random64(), all 64 bits are random before the divide, so the
end result is a random 32-bit value. In addition, ha_random64() is
slow since shared between threads.
Let's use statistical_prng() which is designed for this purpose and
is much cheaper. No backport is needed, this is only in 3.4.
Willy Tarreau [Fri, 22 May 2026 07:49:06 +0000 (07:49 +0000)]
CLEANUP: resolvers: remove pool_free(NULL) in SRV additional record matching
In resolv_validate_dns_response(), when matching an additional A/AAAA
record to an SRV record, the code checked tmp_record->ar_item == NULL
then called pool_free(resolv_answer_item_pool, tmp_record->ar_item).
This is a copy-paste mistake from similar patterns elsewhere since
the pointer is confirmed to be NULL a few lines above, so let's just
drop the confusing pool_free.
Willy Tarreau [Fri, 22 May 2026 06:01:49 +0000 (06:01 +0000)]
CLEANUP: resolvers: use read_n32() instead of open-coded big-endian read
In resolv_validate_dns_response(), the second DNS record parsing path
manually constructs a 32-bit big-endian TTL value from four individual
bytes using the expression:
We have read_n32() to do this, and it's more robust against unexpected
signedness surprises (which should not happen right here since reader is
unsigned char and we use -fwrapv so the result is defined). Also, let's
make the ttl an uint instead of an int. The TTL is only retrieved and not
used for now, so better clean it now.
Willy Tarreau [Sat, 23 May 2026 17:59:31 +0000 (19:59 +0200)]
BUG/MINOR: sample: limit the be2hex converter's chunk size
In 2.5, commit da0264a96 ("MINOR: sample: Add be2hex converter")
introduced the be2hex() converter, which reads input data of a given
chunk size, processes it as a big endian block and turns it to hex
output.
There's an issue if the configured chunk_size (2nd argument) is larger
than tune.bufsize/2, because the max_size calculation will underflow,
and the later loop will always match since it compares a size_t to an
int (BTW, compilers love to annoy us with useless warnings but I never
found how to see some for these ones). This can result in overflowing
the output trash if the input sample is at least as large as half a
buffer.
Let's add an explicit check for this, and change the max_size type to
size_t so that the comparison is always right. While we're at it, let's
ask the trash buffer to be twice as large, just like bin2hex() does, as
it may result in offering a larger buffer in 3.4. thanks to the large
buffers support.
Despite the risk, this is marked as minor because a config with that
large an argument in the converter makes absolutely no sense.
This should be backported to 2.6. The *2 for the trash allocation will
conflict and have to be dropped in stable versions, which is safe.
Willy Tarreau [Sun, 24 May 2026 09:06:31 +0000 (11:06 +0200)]
BUG/MINOR: init: use more than ha_random64() for the cluster secret
When not set, the cluster secret is randomly generated by two
consecutive calls to ha_random64(). However, the random64 PRNG may be
partially observed on a fully idle machine (QUIC retry tokens, UUID,
WS key), and it could be rolled back to the initial call that produced
the secret. This is purely theoretical as a normally loaded system
wouldn't reveal meaningful sequences, but better address this while
it's still easy.
The first here consists in isolating the cluster_secret from the PRNG
sequence. When RAND_bytes() is available and works, it's used. Otherwise
ha_random64() is mixed with uncorrelated bits from random().
Willy Tarreau [Sat, 23 May 2026 20:17:10 +0000 (22:17 +0200)]
BUG/MINOR: dict: fix refcount race on insert collision
In dict_insert(), when ebis_insert() returns an existing node n indicating
that another thread inserted the same key concurrently, the code freed its
own newly-allocated entry and returned the winner without bumping its
refcount. Both callers then held a reference with refcount=1 instead of 2,
so when one expires the other becomes a use-after-free or double-free.
The bug likely comes from the fact that new_dict_entry() creates an entry
with a refcount preset to 1 (saves an atomic op) and that because of this
there is no refcount increment upon a successful insertion in the tree,
resulting in requiring different code paths for collision and normal
insertion.
A simple fix consists in bumping the refcount under the lock and unlocking
only at the end, but this would mean performing two free() calls under a
lock, which we always try to avoid. The code was slightly rearranged so
that we can now bump the existing entry's refcount under the lock in case
of duplicate, or unlock immediately in the common case, so that the free()
call is done out of the lock.
The probably of the race is very low (at peers connection setup only),
reason why it's marked low. This should be backported to all versions.
Willy Tarreau [Sat, 23 May 2026 19:14:04 +0000 (21:14 +0200)]
BUG/MINOR: log: look for the end of priority before the end of the buffer
In parse_log_message(), the first loop looks for '>' that finishes the
priority field, and unfortunately it stops once it has checked the first
byte after the end of the buffer. This means that a priority made only
of digits for the whole buffer would read one extra byte. In practice
since pools have a tag at the end this is only detectable when using ASAN,
but this should be fixed nevertheless.
This can be backported to all versions.
It's worth noting that RFC5424 now says that the PRI field is 1..3
digits only, so maybe at some point we could seriously limit the
length as well.
Willy Tarreau [Sat, 23 May 2026 17:42:43 +0000 (19:42 +0200)]
BUG/MINOR: mux-h2: validate HEADERS frame length before reading stream dep
When the PRIORITY flag is present on a HEADERS frame, the frame must
contain a stream dependency and a weight, for a total of 5 bytes. The
length is checked after reading the stream dep field so theoretically
such a frame could cause up to 4-byte OOB read at the end of the buffer,
though in practice buffers allocated from pools never end on a page
boundary (one extra word at the end) and the anomaly is still detected
after reading the stream ID and the connection aborted with the glitch
count incremented. Thus while not technically correct, practically
speaking it's harmless.
Willy Tarreau [Sat, 23 May 2026 16:55:22 +0000 (18:55 +0200)]
BUG/MINOR: resolvers: fix risk of appending garbage past the domain name
The previous fix 75f72c2eb ("BUG/MEDIUM: resolvers: Fix test on dn label
size in resolv_dn_label_to_str()") may still leave garbage from the input
buffer into the response: if a component length is passed as zero, it
should mark the end, but instead a dot will be emitted, and whatever
follows it in the input buffer would continue to be appended as extra
components. While having no direct consequences beyond the domain not
being properly decoded, it could at least complicate troubleshooting.
This should be backported where the fix above is backported.
Willy Tarreau [Sat, 23 May 2026 16:53:27 +0000 (18:53 +0200)]
BUG/MINOR: resolvers: fix room for trailing zero in resolv_dn_label_to_str()
The previous fix 75f72c2eb ("BUG/MEDIUM: resolvers: Fix test on dn label
size in resolv_dn_label_to_str()") can still be fooled by an input exactly
the size of str_len, in which case the trailing zero appended at the end
was not being accounted for. Let's add 1 to the condition to prepare for
it.
This needs to be backported wherever the fix above is backported.
Willy Tarreau [Fri, 22 May 2026 08:49:17 +0000 (08:49 +0000)]
BUG/MINOR: log: free logformat expr on compile failure in cfg_parse_log_profile
When lf_expr_compile() fails in cfg_parse_log_profile, the code leaves
without freeing the previously strdup()'d strings in target_lf->str and
target_lf->conf.file. Let's add a call to lf_expr_deinit() there to
release it.
It was harmless anyway since the startup will abort when this happens,
but better clean it because with increasingly dynamic setups, one day
it could become a runtime leak.
Willy Tarreau [Sat, 23 May 2026 20:31:58 +0000 (22:31 +0200)]
BUG/MEDIUM: cache: fix a refcount leak for missed secondary entries
When a primary cache hit has a Vary secondary_key_signature, the code calls
retain_entry() and shctx_row_detach() before performing the secondary lookup.
If get_secondary_entry() returns NULL (no stored variant matches), res is set
to NULL and the function falls through to return ACT_RET_CONT without calling
release_entry() or shctx_row_reattach(). Each such request leaks one refcount
and pins one shctx row permanently, eventually exhausting the cache if this
happens to all objects. This is visible when requesting a secondary key
covered by vary for an object that is already stored without that key.
"show cache" then shows the object's refcount increasing after each request.
In order to fix this we must do like when no secondary key could be built
and release everything. We only reattach to the row if we previously
detached.
The issue was introduced in 2.4 with commit 1785f3dd9 ("MEDIUM: cache: Add
the Vary header support"). The code changed a bit in 2.9 with commit 48f81ec09 ("MAJOR: cache: Delay cache entry delete in reserve_hot function"),
so in order to backport to 2.8 and older, the patch will have to be manually
applied (no test on detached).
Willy Tarreau [Sun, 24 May 2026 16:14:50 +0000 (18:14 +0200)]
BUG/MEDIUM: tcpcheck/spoe: bound the SPOP error code to valid values
tcpcheck_spop_expect_hello() stores the SPOA agent-supplied status-code
varint directly into check->code (signed short) without range validation.
The code is later used as an index into spop_err_reasons[100]. Let's
just replace invalid status codes with SPOP_ERR_UNKNOWN to avoid any
problem.
The SPOP tcp-check was introduced in 3.1 so this fix must be backported
to 3.2.
Willy Tarreau [Sun, 24 May 2026 11:11:09 +0000 (13:11 +0200)]
BUG/MEDIUM: regex: allocate a large enough pcre2 match for all matches
In 3.3 with commit fda6dc959 ("MINOR: regex: use a thread-local match
pointer for pcre2") we got a thread-local match that saves us from having
to allocate a match array with each match. However something was clearly
overlooked or misunderstood in the pcre2 API because the local match
array was initialized via pcre2_match_data_create() for MAX_MATCH-1
entries instead of MAX_MATCH, despite the commit message mentioning
MAX_MATCH entries. It was possibly confused with an index. Due to this
there is a risk of crash when matching more than 9 groups in a regex.
Willy Tarreau [Sat, 23 May 2026 18:17:16 +0000 (20:17 +0200)]
BUG/MEDIUM: log-forward: make sure the month is unsigned
In 2.3, in preparation for log forwarding, commit 546488559 ("MEDIUM:
log/sink: re-work and merge of build message API.") extended the log
send API to be able to use metadata from an existing header. However
the month number is parsed from the passed meta-data and compared
against 11 but there's no check for negative values which could in
theory cause a negative monthname[] index.
It can be a problem when the date is received as RFC5424 and forced
to RFC3164 because certain characters in the month field could result
in a negative month value. Let's fix it by turning the month to unsigned
to make sure we only accept months 0..11.
Willy Tarreau [Mon, 25 May 2026 05:23:49 +0000 (07:23 +0200)]
BUILD: intops: mask the fail value in array_size_or_fail()
Cross-compilation on m68k fails in ssl_sock_resize_passphrase_cache()
where the compiler noticed the SIZE_MAX passed to realloc() in the
error path and complained that it's larger than PTRDIFF_MAX. This can
be disabled with -Walloc-size-larger-than=SIZE_MAX but in practice we
can simply hide the value and keep the warning to detect real failures
elsewhere. Let's pass it through DISGUISE() and also take this
opportunity for doing that inside an unlikely() clause since it's never
supposed to happen.
CyberpsychoJacob [Fri, 15 May 2026 07:27:15 +0000 (11:27 +0400)]
BUG/MEDIUM: acme: NUL terminate response buffer before PEM parsing
acme_res_certificate() passes the httpclient response buffer to
ssl_sock_load_pem_into_ckch(), which will then call BIO_new_mem_buf(buf, -1).
The "-1" flag will make the OpenSSL PEM parser determine the length by
using strlen(). However, the httpclient populates the response buffer with
__b_putblk() without writing a trailing NUL to it. The byte at area[data]
is whatever data previously resided there in the memory pool.
Thus, a malicious or compromised ACME CA can perform an arbitrary-length
out-of-bounds read until hitting the first NULL byte past the response
body. The OpenSSL PEM loader will try to iterate to load the chain
certificates, thus the PEM-looking garbage found in freed memory chunks
can be erroneously loaded as additional intermediate certificates. The
presence of a single NUL inside the valid response body will result in
silent truncation of the certificate.
Make sure that the area[data] contains a terminating NULL before passing
the buffer to the parser. Fail on insufficient room for the NUL terminator.
No backport required: The ACME client has been added in 3.x and this
code path didn't exist in 2.x.
BUG/MEDIUM: cli: Fix parsing of pattern finishing a command payload
When the dedidacted buffer to store the command payload was added (c5ae0da62
"MEDIUM: cli: Make a buffer for the command payload"), an bug was
introduced. When the pattern finishing the command payload is found, it is
removed from the buffer. A NULL-bytes is added before it, skipping the
previous newline character.
It worked well in all cases before the commit above, because the commandline
was already parsed and was placed at the beginning of the cmdline buffer.
So, there is always a line before the payload.
Now, the payload is stored in a dedicated buffer. So there is nothing
preceeding it in a buffer. If the payload is empty, we cannot rewind to the
previous line to set the NULL-byte character. We must handle this case to
avoid integer underflow on the payload buffer length.
BUG/MEDIUM: hlua: Fix integer underflow when receiving line from lua cosocket
In hlua_socket_receive_yield(), when we try to get a line, the trailing CRLF is
stripped by decrementing the block length. The '\n' is first skipped, then,
possible a preceeding '\r'. But the block lenght is never checked. If an empty
line is returned, this leads to an integer underflow and most probably to a
crash because this length is used to copy data into a LUA string.
To fix the issue, the block length is now properly tested against 0 before
decrementing it.
This patch must be backported to all stable versions.
BUG/MINOR: tcpchecks: Limit parsing of agent-check reply to the buffer
When parsing the agent-check reply, we first loop on the response to find
the newline character, to add a NULL-byte at the end of the line. However,
this loop is not bounded to the data available in the buffer. So it is
possible to read bytes outside the buffer and eventually write a NULL-byte
ouside the buffer.
So let's check for the end of the buffer when looping on the agent-check
reply.
This patch must be backported to all stable versions.
BUG/MEDIUM: dict: hold lock while decrementing refcount in dict_entry_unref
In dict_entry_unref(), the write lock on d->rwlock was only acquired after
decrementing the refcount. However, between the decrement and the lock,
another thread could increment it by calling dict_insert(). That could lead
to a UAF.
To fix the issue, the call to HA_ATOMIC_SUB_FETCH is moved inside the write
lock.
This patch must be backported to all stable versions.
Amaury Denoyelle [Fri, 22 May 2026 13:49:44 +0000 (15:49 +0200)]
BUG/MINOR: quic: fix ODCID lookup from derived value
In haproxy, when an Initial packet is received, a new connection may be
created and a DCID must be attributed. This CID is derived from the
original DCID used by the client in its first packet. This is an
optimization to avoid storing two CIDs values in the CID tree.
On CID lookup, if the DCID used is not found, derivation is performed
again. This should permit to retrieve the DCID node. However, this
operation is not performed as expected in quic_get_cid_tid(), as the
wrong value is used on the second lookup. Fix this function by using
derive CID for it. Note that retrieve_qc_conn_from_cid() performs the
same lookup but the bug was not present there.
The impact of this bug is relatively low as most clients send a single
Initial packet. Even in case of multiple packets in a single datagram,
this does not cause any issue as the current thread is assigned as
default.
BUG/MEDIUM: ssl-gencert: Unlock LRU cache if failing to generate certificate
In ssl_sock_generate_certificate(), if the LRU cache for generated
certificates is used, the LRU tree is not unlocked on cache miss if the
certificate generation failed. So let's unlock it on error path.
The bug was introduced by the commit fbc98ebcd ("BUG/MEDIUM: ssl: fix error
path on generate-certificates"). So this patch must be backported with the
commit above, so to all stable versions.
BUG/MEDIUM: resolvers: Fix test on dn label size in resolv_dn_label_to_str()
In resolv_dn_label_to_str(), size for a dn label was stored into an integer
from a signed char without a cast to unsigned. So dn label with a size of
128 bytes or more become negative, skipping this way the copy loop and
desynchronizing input vs output.
In addition, the size of the destination string was only checked at the
begining, against the dn string length. But it must also be checked for
every dn label, to be sure. The dn string can be forged to copied more bytes
than expected.
This patch must be backported to all stable versions.
BUG/MEDIUM: applet: Properly handle receives of size 0
when appctx_rcv_buf() function was called to get data from the applet, but
to get zero bytes, nothing was performed and the function early
returned. However, we must at least take care to set SE_FL_WANT_ROOM if
necessary. Otherwise, if data are still blocked in the applet's output
buffer while the EOI/EOS are pending, the information can be reported to the
upper layer and remaining data can be lost.
Indeed, in such case, SE_FL_WANT_ROOM flag is here to specify the applet has
more data to deliver. Thanks to this flag, the stream will wait before
closing. But when appctx_rcv_buf() function is called, this flag is removed by
the stconn. It is the function responsibility to set it again when necessary.
This patch should fix second part of the issue #3366. It must be backported
to 3.0.
Amaury Denoyelle [Thu, 21 May 2026 13:51:34 +0000 (15:51 +0200)]
MINOR: mux_quic: do not crash on unhandled QMux frame reception
Completes qmux_parse_frm() to ensure every frames allowed by QMux
protocol are listed. For now, nothing is implemented except a CHECK_IF()
to report such events.
This is necessary to prevent a crash on abort. Frames not supported by
QMux should already have been rejected prior via qmux_is_frm_valid().
Amaury Denoyelle [Thu, 21 May 2026 13:50:06 +0000 (15:50 +0200)]
MINOR: mux_quic: handle MAX_STREAMS for uni stream in QMux
Handle reception of a MAX_STREAMS frame for unidirectional stream usage
when using QMux. This simply consists in using qcc_recv_max_streams() as
with QUIC protocol.
Amaury Denoyelle [Thu, 21 May 2026 13:48:31 +0000 (15:48 +0200)]
MINOR: mux_quic: handle STOP_SENDING in QMux
Ensure reception of STOP_SENDING via QMux protocol is properly handled.
This simply consists in using qcc_recv_stop_sending() which will update
the associated QCS if found.
BUG/MINOR: ocsp: Manage date too far away in the future
The check on the OCSP response expire time is based on the "Next Update"
field of the response, converted by my_timegm function that returns a
time_t (signed long). It is then stored in the 'expire' field of the
certificate_ocsp structure which is typed as a signed long.
When loading an OCSP response, if the "Next Update" time is too far in
the future and we are running on a 32 bits machine, we might end up with
negative times ireturned by my_timegm, which make the comparison with
the current date fail and raises the "OCSP single response: no longer
valid." error message.
This problem typically happens in the ocsp_auto_update.vtc regtest since
the loaded OCSP response have a "Next Update" field in 2050.
This patch simply changes the type of the expire field to an unsigned
long since the 'my_timegm' function does not return '-1' in case of
error, contrary to the standard 'timegm' one.
Ths patch can be backported to all stable branches.
Use xprt_add_l6hs() at the end of connect_server() if selected MUX layer
relies on a temporary handshake prior to its initialization. This
functions is noop is SSL layer is active.
This change is necessary to support clear QMux on the backend side.
Recently defined <init_xprt> from mux_proto_list is used to render the
code as generic as possible.
Activates xprt_qmux layer if necessary via session_accept_fd(). This is
necessary to be able to support QMux in clear. This operation is noop if
SSL is active, as in this case xprt_qmux will be activated after the SSL
handshake completion.
To ensure MUX init is delayed when running with clear QMux, mask
CO_FL_WAIT_XPRT_L6 is added to test if the embryonic task must be
started instead.
Define a new connection flag mask CO_FL_WAIT_XPRT_L6. This will be used
to indicate that a XPRT layer is running on top of layer 6. For now,
only xprt_qmux implements this method of operation.
MINOR: xprt_qmux: define default value for get_alpn
Extend get_alpn() for xprt_qmux layer. If lower layer does not implement
ALPN negotiation, return a statically default protocol value. Currently
this is set to "h3".
This change is required to support QMux in clear without SSL. In the
future, it could be useful to configure the default protocol, for
example by extending the syntax for the "proto" keyword.
When QMux protocol is used, xprt_qmux layer is setup after SSL handshake
completion but prior to the MUX initialization. Once transport
parameters exchange is successful, the layer is removed and the MUX is
started.
The layer setup operation was performed directly on ssl_sock_io_cb().
Simplify the code by extracting it in a dedicated function
xprt_add_l6hs(). The function is generic so the requested XPRT layer
must be passed as argument.
The code is mostly identical. One difference is that a check is
performed to ensure no SSL handshake is pending. If this is the case,
the function is a noop. This will become useful to support QMux
transparently both in clear or on top of SSL.
Another minor addition is that CO_FL_XPRT_READY flag is automatically
resetted by xprt_add_l6hs(). This allows the code to use
conn_xprt_start() standard function after XPRT init.
Amaury Denoyelle [Thu, 21 May 2026 12:40:15 +0000 (14:40 +0200)]
MINOR: ssl_sock: remove unneeded check on QMux flags
A recent patch has introduced <init_xprt> mux_proto_list member. This
allows to activate QMux on SSL handshake completion without explicit
"proto qmux" setting.
Thanks to this change, on SSL handshake completion it is not necessary
anymore to check for CO_FL_QMUX_* flags.
Willy Tarreau [Thu, 21 May 2026 13:00:12 +0000 (15:00 +0200)]
BUG/MEDIUM: net_helper: fix a remaining possibly infinite loop in converters
The various tcp_option_* converters rely on tcp_fullhdr_find_opt() to
find the option. However, the same bug as fixed in commit dbf471f99a
("BUG/MAJOR: net_helper: ip.fp infinite loop on malformed tcp options")
was also present there, by which an option of length 0 could be looped
over indefinitely. In practice this does not happen since such options
are not valid, but if passed encoded in an HTTP header for example, it
could possibly be passed.
While fixing it, let's check for length >1 in all 3 locations insteead
of only non-zero, since there's no point processing a malformed option
that wouldn't even be properly skipped.
This fix doesn't need to be backported, unless the ip.fp series is.
Willy Tarreau [Thu, 21 May 2026 07:03:03 +0000 (09:03 +0200)]
BUILD: proxy: unstatify the proxies_del_lock to avoid a warning without threads
When threads are disabled, "static __decl_spinlock(foo);" ends up as
"static;", causing a build warning when threads are disabled. We don't
need it to be static so let's drop "static" here. No backport is needed,
this is 3.4-only.
Willy Tarreau [Wed, 20 May 2026 15:46:36 +0000 (17:46 +0200)]
[RELEASE] Released version 3.4-dev13
Released version 3.4-dev13 with the following main changes :
- BUG/MINOR: backend: correct parameter value validation in get_server_ph_post()
- BUG/MINOR: config/dns: properly fail on duplicate nameserver name detection
- BUG/MEDIUM: dns: fix long loops in additional records parse on name failure
- BUG/MEDIUM: resolvers: fix name compression pointer validation in resolv_read_name()
- BUG/MEDIUM: dns: fix memory leak of sockaddr in dns_session_init() error path
- CLEANUP: proxy: fix tiny mistakes in parse error messages
- CLEANUP: dns: fix misleading error messages in dns_stream_init()
- BUG/MINOR: server: better handling of OOM in srv_set_fqdn()
- BUG/MINOR: servers: use proper source of pool_conn_name in srv_settings_cpy()
- BUG/MEDIUM: server/cli: unlock server lock on failure in cli_parse_set_server
- BUG/MINOR: resolvers: fix dangling list pointer in resolvers_new() error paths
- BUG/MINOR: dns: fix dangling dgram pointer on dns_dgram_init() failure path
- BUG/MINOR: proxy: use proxy_drop() in parse_new_proxy() error path
- CLEANUP: resolvers: properly initialize the sample in resolv_action_do_resolve()
- BUG/MINOR: resolvers: report the expression error in the do-resolve() action parser
- BUG/MINOR: resolvers: fix leaked dgram and dns_ring struct in parse_resolve_conf()
- BUG/MINOR: resolvers: fix leaked fields on cfg_parse_resolvers() error paths
- BUG/MINOR: resolvers: fix missing task_idle destruction in resolvers_destroy()
- CLEANUP: proxy: fix duplicate declaration of cli_find_frontend in proxy.h
- CLEANUP: address a few typos and copy-paste errors in httpclient and dns
- DOC: internal: add a few rules about internal core principles
- BUG/MINOR: session/trace: use distinct flags for SESS_EV_END and _ERR
- CLEANUP: stick-table: uniformize the different action_inc_gpc*()
- REGTESTS: do not run quic/tls13_ssl_crt-list_filters in quic openssl compat mode
- REGTESTS: quic/issuers_chain_path: do not forget to enable QUIC compat mode
- BUG/MINOR: sock: store the connection error status
- BUG/MINOR: check: properly report errno in chk_report_conn_err()
- CLEANUP: tcpcheck: mention that we're a bit far for a sync errno
- BUG/MINOR: jwt: fix possible memory leak in convert_ecdsa_sig() error path
- CLEANUP: jwe: fix theoretical overflow in AAD length calculation
- DOC: config: further clarify that resolvers "default" exists
- MINOR: proxy: remove the experimental status on dynamic backends
- BUG/MEDIUM: limits: properly account for global.maxpipes in compute_ideal_maxconn()
- BUG/MINOR: jws: fix OpenSSL 3.0 version check from > to >=
- BUG/MINOR: jws: Add missing return value check (EVP_PKEY_get_bn_param)
- BUG/MINOR: server: Properly handle init-state value during haproxy startup
- BUG/MINOR: httpclient-cli: Destroy http-client context if failing to start it
- BUG/MEDIUM: h1: Skip all h2c values from Upgrade headers during parsing
- BUG/MINOR: h1: Don't mask websocket protocol if multiple protocols used
- MINOR: haterm: Don't init haterm master pipe if not used
- CLEANUP: haterm: Remove "(too old kernel)" from warning message during init
- BUG/MINOR: httpclient-cli: fix uninit variable in error label
- MINOR: mux: Rename the "token" from mux_proto_list to mux_proto
- MEDIUM: connections: Use both mux_proto and alpn to pick a mux
- MINOR: connection: define conn_select_mux_fe()
- MINOR: connection: define conn_select_mux_be()
- MINOR: connection/mux_quic: add MUX <init_xprt> field for QMux handshake
- MINOR: proxy/server: reject TCP ALPN h3 without experimental
- MEDIUM: ssl: allow h3/QMux negotiation without explicit proto
- BUG/MINOR: server: accept server IDs above 2^31 and clarify error message
- BUG/MINOR: backend: fix balance hash calculation when using hash-type none
- MINOR: server: support hash-key id32 for a cleaner distribution
- MINOR: backend: support hash-key guid for a stabler distribution
- MINOR: startup: support unprivileged chroot if possible
- MEDIUM: startup: add automatic chroot feature
- MINOR: h2: explain committed_extra_streams dec on h2_init() error
- OPTIM: h2: do not update committed streams if elasticity disabled
- MINOR: mux_quic: implement basic committed_extra_streams accounting
- MINOR: quic: use stream elasticity value for initial advertisement
- MINOR: mux_quic: define ms_bidi_rel QCC member
- MAJOR: mux_quic: support stream elasticity during connection lifetime
- BUG/MEDIUM: servers: Store the connection hash with the parameter cache
- BUG/MINOR: prevent conn leak in case of xprt_qmux init failure
- BUILD: traces: set a few __maybe_unused on vars used only for traces
- BUILD: traces: add USE_TRACE allowing to disable traces
- MINOR: startup: do not execute chroot() when "/"
- MEDIUM: startup: warn when chroot is not set for root
- BUG/MEDIUM: servers: Don't forget to set srv_hash when needed
- DOC: fix typo on QUIC stream.max-concurrent reference
- BUG/MINOR: mux_quic: do not exceed stream.max-concurrent on backend side
- BUG/MINOR: htx: Fix value of HTX_XFER_HDRS_ONLY flag
- MEDIUM: htx: Improve htx_xfer API to not count HTX meta-data
- BUG/MEDIUM: applet: Fix transfer of HTX data to the applet
- BUG/MEDIUM: htx: Alloc a chunk of right size in htx_replace_blk_value()
- MEDIUM: stick-tables: Avoid freeing elements while holding a lock
- MINOR: intops: add a multiply overflow detection for ulong and size_t
- CLEANUP: tree-wide: use array_size_or_fail() in array size for allocations
- DOC: update supported gcc and openssl versions in INSTALL
Willy Tarreau [Wed, 20 May 2026 15:02:53 +0000 (17:02 +0200)]
CLEANUP: tree-wide: use array_size_or_fail() in array size for allocations
Instead of relying on malloc(n*size), we now pass array_size_or_fail(n,m)
so that it becomes possible to detect overflow. This is particularly
interesting for global settings that might be set large enough to cause
overflows on 32-bit systems for example, resulting in small values that
then cause trouble. Now the overflow will be detected at allocation time.
Around 25 locations were updated.
Willy Tarreau [Wed, 20 May 2026 14:22:51 +0000 (16:22 +0200)]
MINOR: intops: add a multiply overflow detection for ulong and size_t
Sometimes we'd like to know if some products overflow, so let's add a
pair of functions for this, for ulong and for size_t. For recent enough
compilers (gcc >= 5, clang >= 3.4) we just use __builtin_mul_overflow()
otherwise we rely on a division and a comparison before performing the
operation.
A third function, array_size_or_fail() computes the size of an array
of m elements of n bytes each, and returns the total size if it fits
in a size_t, otherwise ~0 if it does not so that passing this to
malloc() or any other variant would fail by trying to exhaust the
entire memory space.
Olivier Houchard [Wed, 20 May 2026 14:07:13 +0000 (16:07 +0200)]
MEDIUM: stick-tables: Avoid freeing elements while holding a lock
In stksess_trash_oldest(), and process_tables_expire(), avoid freeing
elements while holding two locks, as it could be very costly.
Instead, build a linked list of elements to be free'd, and do so once we
no longer hold any lock.
This may help with github issue #3380, and may be backported to 3.3.
BUG/MEDIUM: htx: Alloc a chunk of right size in htx_replace_blk_value()
Since support for large buffers was added, we must be careful when chunks
are allocated. Indeed, depending on the context a large chunks may be
required if data are copied from a large buffer.
In htx_replace_blk_value() function, when a defragmentation is necessary,
the data to be replaced are copied to a chunk before the
defragmentation. However, I forgot to get large chunk when necessary by
calling alloc_trash_chunk_sz() instead of alloc_trash_chunk(). Because of
this issue, it is possible to copy data to a too small chunk, leading to a
crash.
So let's fix the issue.
Thanks to Vincent55 for finding and reporting this.
BUG/MEDIUM: applet: Fix transfer of HTX data to the applet
appctx_htx_snd_buf() function is relying on htx_xfer() function to transfer
HTX blocks when a swap of buffers is not possible. However, it was not
properly using this function.
Indeed, originally htx_xfer() was designed to transfer blocks with a limit,
the <count> parameter, which included the blocks payload and the
meta-data. It was aligned with all calls, except for the transfer of HTX
data to the applet, in appctx_htx_snd_buf() function. In that case, the
<count> parameter is the amount of data forwarded by the stream to the
applet. So meta-data are not included.
Thanks to the previous commit ("MEDIUM: htx: Improve htx_xfer API to not count
HTX meta-data"), it is now possible to instruct htx_xfer() function that
<count> parameter does not include the meta-data.
Because of this bug, crashes can be experienced when transferring HTX data
to an applet. At first glance, lua HTTP applets and the http client are
concerned.
Stable versions from 3.3 to 3.0 are also affected. But this patch cannot be
backported as is because htx_xfer() function does not exist on these
versions.
Thaks to Yon Harlicaj for finding and reporting this.
(https://x.com/nvmb3r - https://www.linkedin.com/in/eljon-harlicaj/)
MEDIUM: htx: Improve htx_xfer API to not count HTX meta-data
This patch add the ability to the htx_xfer() function to transfer data
without acounting the meta-data. By default, the <count> variable includes
the meta-data. But by setting the flag HTX_XFER_NO_METADATA, It is possible
to transfer HTX blocks without count meta-data. In that case, <count> will
not contain the blocks meta-data and the return value will not include them.
Amaury Denoyelle [Mon, 18 May 2026 08:53:37 +0000 (10:53 +0200)]
BUG/MINOR: mux_quic: do not exceed stream.max-concurrent on backend side
Fix usage of stream.max-concurrent QUIC setting on the backend side.
Contrary to frontend connections, this limit must be enforced by QUIC
MUX directly. This is necessary as the peer may allow a larger number of
concurrent streams via its flow control.
First, QUIC TP initial max bidi streams value is now set to 0. This is
fine as only the HTTP/3 client is expected to open bidirectional
streams.
The most important changes is performed in qcm_avail_streams(). The
value first depends on the peer flow control. Now, it is further reduced
if necessary to not exceed the configured BE stream.max-concurrent.
Note that this new behavior may further increases current limitation on
QUIC BE reuse when a QCS instance is kept while its upper stream layer
is detached. In this case there is a risk that the connection is not
reinserted in the correct server pool, as an idle or avail one.
This is a breaking change as BE stream.max-concurrent keyword setting
meaning is changed in effect. However, this does not necessitate extra
warnings as the previous usage was in effect useless. Furthermore, QUIC
on the backend side is still considered as experimental.
Olivier Houchard [Wed, 20 May 2026 11:05:05 +0000 (13:05 +0200)]
BUG/MEDIUM: servers: Don't forget to set srv_hash when needed
Commit 8aa854ab26a7daa613a17548f1fe1d0adb8cf61b made it so we'd store
the hash corresponding to the server parameters, so that we could detect
if we're still talking to the same server, and not use those parameters
if not.
However, when updating those parameters, we forgot to store the new
hash, which would result in the new parameters never be used, and
breakling 0RTT.
Fix that by properly update the hash when needed.
This should be backported when 8aa854ab26a7daa613a17548f1fe1d0adb8cf61b
is backported.
Willy Tarreau [Wed, 20 May 2026 09:30:32 +0000 (11:30 +0200)]
MEDIUM: startup: warn when chroot is not set for root
We're still regularly seeing insecure configs where chroot is missing.
Now that we have "chroot auto", there's no excuse for not knowing where
to chroot, so let's detect that we're starting as root, detect that the
process is allowed to chroot (i.e. no capability issue, or some hardened
containers), and if no chroot is set, let's emit a warning explaining how
to silence it, i.e. either "chroot auto" or "chroot /".
Most likely we'll start using "chroot auto" by default in 3.5 if no
usability issue is reported.
Willy Tarreau [Wed, 20 May 2026 09:05:17 +0000 (11:05 +0200)]
MINOR: startup: do not execute chroot() when "/"
We'll recommend to use "chroot /" to explicitly disable chroot, however
there might be configurations where it would cause problems to just issue
the syscall (typically some hardened containers), so let's make sure that
"chroot /" is a nop in this case.
BUILD: traces: add USE_TRACE allowing to disable traces
This reduces the total code size by 6-10% and speeds up the build a
bit. It can be further reduced by disabling the trace decoding code
inside certain subsystems like muxes. But at least like this it will
help users on small systems to reduce the footprint when not needed
by explicitly passing USE_TRACE=0 (they remain enabled by default).
BUG/MINOR: prevent conn leak in case of xprt_qmux init failure
In case of XPRT_QMUX init failure on the frontend side, the connection
must immediately be released. This is not the case on the backend side
as a stream can supervize the connection lifetime.
This patch performs the connection free via conn_complete_session(). As
conn is flagged with CO_FL_ERROR, this will automatically fail and
invoke session_kill_embryonic(), which ensures the session and its
connection are both freed as wanted in this case.
Olivier Houchard [Tue, 19 May 2026 11:23:21 +0000 (13:23 +0200)]
BUG/MEDIUM: servers: Store the connection hash with the parameter cache
When we store the negociated server parameters, such as the ALPN, also
store the calculated hash with the connection. If it is different, as
can happen because the IP address is different because set-dst was used,
we certainly do not want to reuse the information in the cache,
otherwise we could end up using the wrong ALPN and mux.
That means we already have to calculate the hash in connect_server()
now, while before we would not do it for Websockets, if we could not do
connection reuse, as that's all the hash was used for.
Amaury Denoyelle [Fri, 15 May 2026 14:56:00 +0000 (16:56 +0200)]
MAJOR: mux_quic: support stream elasticity during connection lifetime
qcc_release_remote_stream() is called each time a remote stream is
closed. Flow control accounting is updated and when necessary, a
MAX_STREAMS_BIDI frame is prepared to allow the peer to initiate new
streams.
This patch extends stream elasticity features with the QUIC bidirection
stream flow control mechanism. The announced value can now be possibly
reduced depending on conn_calc_max_streams().
The first step is to decrement closed streams from the global committed
extra streams total. This must be performed conn_calc_max_streams() to
ensure the calculation will be valid.
Then, there is two cases depending on conn_calc_max_streams() result. If
the value is less than the peer still remaining stream window, nothing
more is performed. If the opposite case, flow control must be increased
and a MAX_STREAMS_BIDI frame is prepared, with the value adjusted to not
exceed the stream elasticity limit. Global extra streams total is then
finally incremented.
This calcul also ensures that when all streams are closed, global extra
streams accounting operations are decremented by 1, as a connection
always has access to one stream which is excluded from the global total.
Note that if stream elasticity is not active, flow control increases
principle is unchanged and remains statically performed.
This patch is labelled as major as it complexifies bidirectional stream
flow control mechanisme. This is a sensitive operation as there is a
risk of connection freeze if flow control updates are inadvertently
skipped.
Amaury Denoyelle [Fri, 15 May 2026 14:55:32 +0000 (16:55 +0200)]
MINOR: mux_quic: define ms_bidi_rel QCC member
Add a new QCC member <ms_bidi_rel>. This represents the number of
concurrent streams advertised similarly to ms_bidi, but as a relative
value.
This patch does not introduce any functional change. For now,
<ms_bidi_rel> will be equal to <ms_bidi_init>. However, with the
implementation of stream elasticity and dynamic adjustment for
concurrent max-streams-bidi, the former will be required to keep the
last advertised value.
Amaury Denoyelle [Mon, 18 May 2026 06:27:32 +0000 (08:27 +0200)]
MINOR: quic: use stream elasticity value for initial advertisement
When stream elasticity is active, the maximum number of concurrent bidi
streams advertised via transport parameters is now reduced depending on
the connection load. This is implemented via conn_calc_max_streams()
which returns the value to use.
This is not applied on listeners with enabled 0-RTT. Indeed, for such
connections, clients are expected to reuse the previously seen transport
parameters. The server on the other hand must not decrease several
values on the newly advertised params, in particular for the maximum
number of concurrent bidi streams. The simplest way to prevent 0-RTT
failure is to not mix stream elasticity with it.
Note that the 0-RTT limitation is only applied for the initial value :
during the connection lifetime, stream elasticity can still be used by
the MUX to dynamically reduce the stream window. This will be
implemented in a future patch.
Account QUIC frontend connections into committed_extra_streams when
stream elasticity setting is active. This is performed in QCC init and
release functions.
This patch has no impact on QUIC subsystem for now. Connections will
still allow a static number of concurrent streams based on
tune.quic.fe.stream.max-concurrent. However, this has a direct
repercussion on H2 subsystem, as a higher count of QUIC connections will
reduce the concurrent streams allowed there.
Amaury Denoyelle [Wed, 20 May 2026 07:01:04 +0000 (09:01 +0200)]
OPTIM: h2: do not update committed streams if elasticity disabled
When streams-elasticity is enabled in the configuration, H2 mux is
responsible to update the global committed_extra_streams value.
Adjust these operations to ensure they are skipped if streams-elasticity
is disabled, which is the current default. This prevents unnecessary
atomic operations in this case.
No need to backport unless streams-elasticity feature is picked in older
releases.
Amaury Denoyelle [Wed, 13 May 2026 06:02:09 +0000 (08:02 +0200)]
MINOR: h2: explain committed_extra_streams dec on h2_init() error
h2_init() is now responsible to increment committed_extra_streams for
new frontend connections, in relation to the newly implemented
stream-elasticity feature. In case of an early error, a mirroring
decrement is executed on fail_stream label.
However, for now this error label can only be selected via BE conns. In
fact, it's not yet possible for h2_init() to fail after the extra
streams increment.
However, the decrement operation is kept to prevent any omissions in
case of future evolutions of h2_init() error path. To prevent reporting
of a possible dead code, add an extra comment which summarizes the
situation.
Maxime Henrion [Tue, 12 May 2026 14:21:40 +0000 (10:21 -0400)]
MEDIUM: startup: add automatic chroot feature
It is now possible to use "chroot auto" in the configuration. This lets
haproxy create an anonymous (cleaned up after the process terminates)
and read-only directory for chroot. This directory is created in /tmp;
we might want to support creating it in a different directory in the
future, either by respecting $TMPDIR or by allowing an optional
directory after the "auto" keyword.
Willy Tarreau [Tue, 19 May 2026 17:06:32 +0000 (19:06 +0200)]
MINOR: backend: support hash-key guid for a stabler distribution
When server fleets are constantly updated, using a stable distribution
across a bunch of load balancers can be convenient. The addr and port
already provide a bit of this but for situations were addresses might
differ between sites or change dynamically this does not work. The guid
is perfect for this because by definition it's supposed to designate a
single server and be unique. So when two servers anywhere have the same,
the tool that provisionned them promises that they are the same server.
So here we introduce "hash-key guid" which performs a 32-bit hash on
the GUID value. When no guid is provided, a fallback is performed on
ID, as is done for other keys.
Willy Tarreau [Tue, 19 May 2026 16:35:06 +0000 (18:35 +0200)]
MINOR: server: support hash-key id32 for a cleaner distribution
The "id" hash-key scales the ID by a factor of 16 that tries to leave
room between the nodes on the 32-bit space to permit smooth weight
variations (e.g. during slowstart). However this does not deal well
with overlaps between server IDs. For example, assigning IDs that are
only multiples of 256 million to 16 servers yields traffic only on
one since in practice they all have the same 28 lower bits.
The new "id32" hash key bridges this gap by using the full 32-bit ID
of the server as the key. On the other hand, the user must be careful
not to switch the hash function to "none" when using incremental IDs
because in this case they might be very poorly distributed. But this
can be convenient for automated provisionning systems which assign
IDs themselves, as the full 32 bits are used now.
Willy Tarreau [Tue, 19 May 2026 16:18:23 +0000 (18:18 +0200)]
BUG/MINOR: backend: fix balance hash calculation when using hash-type none
The "hash-type xxx none" is broken for keys that are not in type string
because the sample fetch call casts them to SMP_T_BIN, that tends to
preserve the original format (integers, IP addresses etc), but the
gen_hash() function in case of BE_LB_HFCN_NONE expects to read a string
representing a number, that it parses to retrieve the value, and just
fails on many binary types. For example, the following just always
returns key 0:
balance hash rand()
hash type consistent none
An ugly workaround is to make sure the expression returns a string, for
example this:
balance hash rand(),concat()
hash type consistent none
In order to fix most cases here, we force the conversion to type string
when using BE_LB_HFCN_NONE, but a better approach would require a larger
rework and split gen_hash() or change it to accept an integer as well,
so that the caller could cast to SMP_T_INT for BE_LB_HFCN_NONE and pass
the resulting number already parsed with the least information loss. In
this case even IPv4 addresses would be preserved.
The current approach at least addresses the initially envisioned use
cases, and the limitations have been added to the doc. This can be
backported to 3.0 though it's not really important.
Willy Tarreau [Tue, 19 May 2026 14:59:37 +0000 (16:59 +0200)]
BUG/MINOR: server: accept server IDs above 2^31 and clarify error message
Due to the check of the stored value instead of the parsed one, it was not
permitted to use server IDs above 2^31 while they are perfectly possible.
Let's refine the parsing and also update the error message to indicate the
range. The doc was also refined to reflect the relation with hash-key.
This may be backported though it wouldn't have any effect on working
configs.
Amaury Denoyelle [Tue, 19 May 2026 15:54:05 +0000 (17:54 +0200)]
MEDIUM: ssl: allow h3/QMux negotiation without explicit proto
Implements automatic selection of QMux MUX if "h3" ALPN has been
negotiated on top of TCP/SSL.
The first part of this change is to define "alpn" member of
mux_proto_list. This is necessary so that conn_get_best_mux_entry() can
select it when "h3" has been chosen. As a side-effect, this also
automatically sets a default ALPN to "h3" for bind lines with "proto
qmux".
The most important change is to adapt the SSL layer. On handshake
completion, the eligible MUX is retrieved via conn_select_mux_fe/be()
functions. If xprt_qmux is required by it, MUX init is delayed and QMux
handshake is started first.
This last change is necessary as connection flags CO_FL_QMUX_RECV/SEND
are only set if "proto qmux" is explicitely set. In case xprt_qmux is
activated via pure ALPN negotiation, these flags are also set on
xprt_qmux_init(). This is mandatory to ensure emission/reception of QMux
transport parameters will be performed as expected.
Amaury Denoyelle [Tue, 19 May 2026 14:30:40 +0000 (16:30 +0200)]
MINOR: proxy/server: reject TCP ALPN h3 without experimental
Add a postparsing check on TCP ALPN bind and server setting. An error is
reported if the token "h3" is present and expose-experimental-directives
is not globally activated. This ensures that QMux protocol won't be
selected if experimental features are not explicitely requested.
The check is not performed though if "proto qmux" is explicitely
defined, as this setting already checks for experimental support.
Currently, it's not possible to activate QMux without any explicit
"proto qmux" config. However, this will be implemented in a next patch,
so this check will become necessary.
Amaury Denoyelle [Mon, 18 May 2026 14:58:04 +0000 (16:58 +0200)]
MINOR: connection/mux_quic: add MUX <init_xprt> field for QMux handshake
The first part of this patch defines a new mux_proto_list field named
<xprt_init>. This allows to define an extra XPRT layer which should be
activated first prior to the MUX creation both on frontend and backend
sides.
This is immediately used for QMux mux_proto_list to require XPRT_QMUX
handshake. With this change, activation of QMux connection flags in
session_accept_fd() and connect_server() are adjusted to take into
account <init_xprt> field. This approach is much more evolutive than
relying on the previous MUX name.
Change in connect_server() will also be necessary to support QMux
activation on a TCP server with h3 ALPN without explicit "proto qmux".
This guarantees that MUX initialization is delayed after QMux handshake.
Amaury Denoyelle [Tue, 19 May 2026 13:02:23 +0000 (15:02 +0200)]
MINOR: connection: define conn_select_mux_be()
This patch is similar to the previous one but this time for backend
connections. The MUX selection code is directly extracted from
conn_install_mux_chk() and conn_install_mux_be().
Amaury Denoyelle [Mon, 18 May 2026 14:57:05 +0000 (16:57 +0200)]
MINOR: connection: define conn_select_mux_fe()
Define a new function conn_select_mux_fe().
The objective is to have a preliminary function to determine the MUX
which will be used without initializing it. This will be useful for MUX
which relies on a specific XPRT handshake prior to its startup, which is
the case for QMux protocol.
The code of conn_select_mux_fe() is identical to the beginning of
conn_install_mux_fe() with a similar MUX selection logic. However,
connection MUX initialization is not performed in this case. In a future
patch, both functions should be merged together to reduce code
duplication.
Olivier Houchard [Tue, 19 May 2026 13:52:21 +0000 (15:52 +0200)]
MEDIUM: connections: Use both mux_proto and alpn to pick a mux
In conn_get_best_mux() and conn_get_best_mux_entry(), the mux name was
provided sometimes based on the "proto" directive, sometimes based on
the ALPN, but in any case, it was compared again the mux_proto_list
mux_proto field. This is not correct, as ALPN can be different from the
internal mux_proto. So enhance those functions so that they wll accept
an ALPN as well. If a mux_proto is provided, that will be used, if not,
and if an ALPN is provided, then that will be used, and compared against
the ALPN provided by the mux, if any.
Olivier Houchard [Tue, 19 May 2026 12:46:25 +0000 (14:46 +0200)]
MINOR: mux: Rename the "token" from mux_proto_list to mux_proto
In struct mux_proto_list, rename the "token" field to "mux_proto". That
field should only be used to match the name provided in the "proto"
directive, and it will be soon.
This should be a no-op.
However, error label may be selected prior to httpclient allocation if
CLI arguments are incorrect. This can cause a crash due to a deferencing
of an uninitialized variable. This has been detected via a compilation
error :
src/httpclient_cli.c: In function 'hc_cli_parse':
src/httpclient_cli.c:162:2: error: 'hc' may be used uninitialized in this function [-Werror=maybe-uninitialized]
162 | httpclient_destroy(hc);
| ^~~~~~~~~~~~~~~~~~~~~~
This must be backported along the above patch, which is scheduled up to
the 2.6 release.
CLEANUP: haterm: Remove "(too old kernel)" from warning message during init
During initialization of the haterm master pipe, If its size is limited
(lower than the configured one * 5/4), a warning is emitted. In this
warning, it is specified this happened because the kernel is too old. But it
is unrelated. So let's remove this part.
MINOR: haterm: Don't init haterm master pipe if not used
There is no reason to initialize the haterm master pipe if haterm is not
used. So now, it is only performed if a non-disabled haterm frontend is
found. To do so, in addition to test the proxy's flags and capabilities, we
also check if "stream_new_from_sc" points on "hstream_new".