Right now we have a per-process max variable size and a per-scope one,
with the proc scope covering all others. As such, the per-process global
one is always exactly equal to the per-proc-scope one. And bookkeeping
on these process-wide variables is extremely expensive (up to 38% CPU
seen in var_accounting_diff() just for them).
Let's kill vars_global_size and only rely on the proc one. Doing this
increased the request rate from 770k to 1.06M in a config having only
12 variables on a 16-thread machine.
There's no point taking the variables locks for sess/txn/req/res
contexts since these ones always run inside the same thread anyway.
This patch conditions the lock on the variable's scope to avoid
flushing cache lines when not needed.
This showed an improvement of ~5% on a 16-thread machine with 12
variables.
The global table of known variables names can only grow and was designed
for static names that are registered at boot. Nowadays it's possible to
set dynamic variable names from Lua or from the CLI, which causes a real
problem that was partially addressed in 2.2 with commit 4e172c93f
("MEDIUM: lua: Add `ifexist` parameter to `set_var`"). Please see github
issue #624 for more context.
This patch simplifies all this by removing the need for a central
registry of known names, and storing 64-bit hashes instead. This is
highly sufficient given the low number of variables in each context.
The hash is calculated using XXH64() which is bijective over the 64-bit
space thus is guaranteed collision-free for 1..8 chars. Above that the
risk remains around 1/2^64 per extra 8 chars so in practice this is
highly sufficient for our usage. A random seed is used at boot to seed
the hash so that it's not attackable from Lua for example.
There's one particular nit though. The "ifexist" hack mentioned above
is now limited to variables of scope "proc" only, and will only match
variables that were already created or declared, but will now verify
the scope as well. This may affect some bogus Lua scripts and SPOE
agents which used to accidentally work because a similarly named
variable used to exist in a different scope. These ones may need to be
fixed to comply with the doc.
Now we can sum up the situation as this one:
- ephemeral variables (scopes sess, txn, req, res) will always be
usable, regardless of any prior declaration. This effectively
addresses the most problematic change from the commit above that
in order to work well could have required some script auditing ;
- process-wide variables (scope proc) that are mentioned in the
configuration, referenced in a "register-var-names" SPOE directive,
or created via "set-var" in the global section or the CLI, are
permanent and will always accept to be set, with or without the
"ifexist" restriction (SPOE uses this internally as well).
- process-wide variables (scope proc) that are only created via a
set-var() tcp/http action, via Lua's set_var() calls, or via an
SPOE with the "force-set-var" directive), will not be permanent
but will always accept to be replaced once they are created, even
if "ifexist" is present
- process-wide variables (scope proc) that do not exist will only
support being created via the set-var() tcp/http action, Lua's
set_var() calls without "ifexist", or an SPOE declared with
"force-set-var".
This means that non-proc variables do not care about "ifexist" nor
prior declaration, and that using "ifexist" should most often be
reliable in Lua and that SPOE should most often work without any
prior declaration. It may be doable to turn "ifexist" to 1 by default
in Lua to further ease the transition. Note: regtests were adjusted.
Cc: Tim Düsterhus <tim@bastelstu.be>
Variables names will be hashed, but for this we need a random seed.
The XXH3() algorithms is bijective over the whole 64-bit space, which
is great as it guarantees no collision for 1..8 byte names. But above
that even if the risk is extremely faint, it theoretically exists and
since variables may be set from Lua we'd rather do our best to limit
the risk of controlled collision, hence the random seed.
All variables whose names are parsed by the config parser, the
command-line parser or the SPOE's register-var-names parser are
now preset as permanent. This will guarantee that these variables
will exist through out all the process' life, and that it will be
possible to implement the "ifexist" feature by looking them up.
This was marked medium because pre-setting a variable with an empty
value may always have side effects, even though none was spotted at
this stage.
We certainly do not want that a permanent variable (one that is listed
in the configuration) be erased by accident by an "unset-var" action.
Let's make sure these ones are only reset to an empty sample, like at
the moment of their initial registration. One trick is that the same
function is used to purge the memory at the end and to delete, so we
need to add an extra "force" argument to make the choice.
In order to continue to honor the ifexist Lua option and prevent rogue
SPOA agents from creating too many variables, we'll need to keep the
ability to mark certain proc.* variables as permanent when they're
known from the config file.
Let's add a flag there for this. It's added to the variable when the
variable is created with this flag set by the caller.
Another approach could have been to use a distinct list or distinct
scope but that sounds complicated and bug-prone.
Storing an unset sample (SMP_T_ANY == 0) will be used to only reserve
the variable's space but associate no value. We need to slightly adjust
var_to_smp() for this so that it considers a value-less variable as non
existent and falls back to the default value.
Passing this flag to var_set() will result in the variable to only be
created if it did not exist, otherwise nothing is done (it's not even
updated). This will be used for pre-registering names.
When setting variables, there are currently two variants, one which will
always create the variable, and another one, "ifexist", which will only
create or update a variable if a similarly named variable in any scope
already existed before.
The goal was to limit the risk of injecting random names in the proc
scope, but it was achieved by making use of the somewhat limited name
indexing model, which explains the scope-agnostic restriction.
With this change, we're moving the check downwards in the chain, at the
variable level, and only variables under the scope "proc" will be subject
to the restriction. A new set of VF_* flags was added to adjust how
variables are set, and VF_UPDATEONLY is used to mention this restriction.
In this exact state of affairs, this is not completely exact, as if a
similar name was not known in any scope, the variable will continue to
be rejected like before, but this will change soon.
The names for these two functions are totally misleading, they have
nothing to do with samples, they're purely dedicated to variables. The
former is only used by the second one and makes no sense by itself, so
it cannot even get a meaningful name. Let's remerge them into a single
one called "var_set()" which, as its name tries to imply, sets a variable
to a given value.
This name was quite misleading, as it has nothing to do with samples nor
streams. This function's sole purpose is to unset a variable, so let's
call it "var_unset()" and document it a little bit.
The vars_init() name is particularly confusing as it does not initialize
the variables code but the head of a list of variables passed in
arguments. And we'll soon need to have proper initialization code, so
let's rename it now.
In ticket #1348 some users expressed some concerns regarding the removal
of the "grace" directive from the proxies. Their use case very closely
mimmicks the original intent of the grace keyword, which is, let haproxy
accept traffic for some time when stopping, while indicating an external
LB that it's stopping.
This is implemented here by starting a task whose expiration triggers
the soft-stop for real. The global "stopping" variable is immediately
set however. For example, this below will be sufficient to instantly
notify an external check on port 9999 that the service is going down,
while other services remain active for 10s:
global
grace 10s
frontend ext-check
bind :9999
monitor-uri /ext-check
monitor fail if { stopping }
This reverts commit e0dec4b7b2.
At first glance, channel_is_empty() was used on purpose in si_update_rx(),
because of the HTX ("b3e0de46c" MEDIUM: stream-int: Rely only on
SI_FL_WAIT_ROOM to stop data receipt). It is not pretty clear for now why
channel_may_recv() sould not be used here but this change introduce a
possible infinite loop with the stats applet. So, it is safer to revert the
patch, waiting for a better understanding of the probelm.
This means the abortonclose option will be broken again on the 2.3 and lower
versions.
This patch should fix the issue #1360. It must be backported as far as 2.0.
Ori Hollander of JFrog Security reported that htx_add_header() and
htx_add_trailer() were missing a length check on the header name. While
this does not allow to overwrite any memory area, it results in bits of
the header name length to slip into the header value length and may
result in forging certain header names on the input. The sad thing here
is that a FIXME comment was present suggesting to add the required length
checks :-(
The injected headers are visible to the HTTP internals and to the config
rules, so haproxy will generally stay synchronized with the server. But
there is one exception which is the content-length header field, because
it is already deduplicated on the input, but before being indexed. As
such, injecting a content-length header after the deduplication stage
may be abused to present a different, shorter one on the other side and
help build a request smuggling attack, or even maybe a response splitting
attack. CVE-2021-40346 was assigned to this problem.
As a mitigation measure, it is sufficient to verify that no more than
one such header is present in any message, which is normally the case
thanks to the duplicate checks:
http-request deny if { req.hdr_cnt(content-length) gt 1 }
http-response deny if { res.hdr_cnt(content-length) gt 1 }
This must be backported to all HTX-enabled versions, hence as far as 2.0.
In 2.3 and earlier, the functions are in src/htx.c instead.
Many thanks to Ori for his work and his responsible report!
Since commit "BUG/MINOR: config: reject configs using HTTP with bufsize
>= 256 MB" we are now sure that it's not possible anymore to have an HTX
block of a size 256 MB or more, even after concatenation thanks to the
tests for len >= htx_free_data_space(). Let's remove these now obsolete
comments.
A BUG_ON() was added in htx_add_blk() to track any such exception if
the conditions would change later, to complete the one that is performed
on the start address that must remain within the buffer.
As seen in commit 5ef965606 ("BUG/MINOR: lua: use strlcpy2() not
strncpy() to copy sample keywords"), configs with large values of
tune.bufsize were not practically usable since Lua was introduced,
regardless of the machine's available memory.
In addition, HTX encoding already limits block sizes to 256 MB, thus
it is not technically possible to use that large a buffer size when
HTTP is in use. This is absurdly high anyway, and for example Lua
initialization would take around one minute on a 4 GHz CPU. Better
prevent such a config from starting than having to deal with bug
reports that make no sense.
The check is only enforced if at least one HTX proxy was found, as
there is no techincal reason to block it for configs that are solely
based on raw TCP, and it could still be imagined that some such might
exist with single connections (e.g. a log forwarder that buffers to
cover for the storage I/O latencies).
This should be backported to all HTX-enabled versions (2.0 and above).
Released version 2.5-dev6 with the following main changes :
- BUG/MINOR threads: Use get_(local|gm)time instead of (local|gm)time
- BUG/MINOR: tools: Fix loop condition in dump_text()
- BUILD: ssl: next round of build warnings on LIBRESSL_VERSION_NUMBER
- BUILD: ssl: fix two remaining occurrences of #if USE_OPENSSL
- BUILD: tools: properly guard __GLIBC__ with defined()
- BUILD: globally enable -Wundef
- MINOR: log: Remove log-error-via-logformat option
- MINOR: log: Add new "error-log-format" option
- BUG/MAJOR: queue: better protect a pendconn being picked from the proxy
- CLEANUP: Add missing include guard to signal.h
- MINOR: ssl: Add new ssl_bc_hsk_err sample fetch
- MINOR: connection: Add a connection error code sample fetch for backend side
- REGTESTS: ssl: Add tests for bc_conn_err and ssl_bc_hsk_err sample fetches
- MINOR: http-rules: add a new "ignore-empty" option to redirects.
- CI: Github Actions: temporarily disable BoringSSL builds
- BUG/MINOR: vars: fix set-var/unset-var exclusivity in the keyword parser
- BUG/MINOR: vars: improve accuracy of the rules used to check expression validity
- MINOR: sample: add missing ARGC_ entries
- BUG/MINOR: vars: properly set the argument parsing context in the expression
- DOC: configuration: remove wrong tcp-request examples in tcp-response
- MEDIUM: vars: add a new "set-var-fmt" action
- BUG/MEDIUM: vars: run over the correct list in release_store_rules()
- BUG/MINOR: vars: truncate the variable name in error reports about scope.
- BUG/MINOR: vars: do not talk about global section in CLI errors for set-var
- CLEANUP: vars: name the temporary proxy "CFG" instead of "CLI" for global vars
- MINOR: log: make log-format expressions completely usable outside of req/resp
- MINOR: vars: add a "set-var-fmt" directive to the global section
- MEDIUM: vars: also support format strings in CLI's "set var" command
- CLEANUP: vars: factor out common code from vars_get_by_{desc,name}
- MINOR: vars: make vars_get_by_* support an optional default value
- MINOR: vars: make the vars() sample fetch function support a default value
- BUILD: ot: add argument for default value to vars_get_by_name()
The API was extended by commit e352b9dac ("MINOR: vars: make vars_get_by_*
support an optional default value") but I didn't notice that opentracing
was using it, so it broke the build. No backport needed.
It is quite common to see in configurations constructions like the
following one:
http-request set-var(txn.bodylen) 0
http-request set-var(txn.bodylen) req.hdr(content-length)
...
http-request set-header orig-len %[var(txn.bodylen)]
The set-var() rules are almost always duplicated when manipulating
integers or any other value that is mandatory along operations. This is
a problem because it makes the configurations complicated to maintain
and slower than needed. And it becomes even more complicated when several
conditions may set the same variable because the risk of forgetting to
initialize it or to accidentally reset it is high.
This patch extends the var() sample fetch function to take an optional
argument which contains a default value to be returned if the variable
was not set. This way it becomes much simpler to use the variable, just
set it where needed, and read it with a fall back to the default value:
http-request set-var(txn.bodylen) req.hdr(content-length)
...
http-request set-header orig-len %[var(txn.bodylen,0)]
The default value is always passed as a string, thus it will experience
a cast to the output type. It doesn't seem userful to complicate the
configuration to pass an explicit type at this point.
The vars.vtc regtest was updated accordingly.
In preparation for support default values when fetching variables, we
need to update the internal API to pass an extra argument to functions
vars_get_by_{name,desc} to provide an optional default value. This
patch does this and always passes NULL in this argument. var_to_smp()
was extended to fall back to this value when available.
The two functions vars_get_by_name() and vars_get_by_scope() perform
almost the same operations except that they differ from the way the
name and scope are retrieved. The second part in common is more
complex and involves locking, so better factor this one out into a
new function.
There is no other change than refactoring.
Most often "set var" on the CLI is used to set a string, and using only
expressions is not always convenient, particularly when trying to
concatenate variables sur as host names and paths.
Now the "set var" command supports an optional keyword before the value
to indicate its type. "expr" takes an expression just like before this
patch, and "fmt" a format string, making it work like the "set-var-fmt"
actions.
The VTC was updated to include a test on the format string.
Just like the set-var-fmt action for tcp/http rules, the set-var-fmt
directive in global sections allows to pre-set process-wide variables
using a format string instead of a sample expression. This is often
more convenient when it is required to concatenate multiple fields,
or when emitting just one word.
The log-format strings are usable at plenty of places, but the expressions
using %[] were restricted to request or response context and nothing else.
This prevents from using them from the config context or the CLI, let's
relax this.
We're using a dummy temporary proxy when creating global variables in
the configuration file, it was copied from the CLI's code and was
mistakenly called "CLI", better name it "CFG". It should not appear
anywhere except maybe when debugging cores.
When attempting to set a variable does not start with the "proc" scope on
the CLI, we used to emit "only proc is permitted in the global section"
which obviously is a leftover from the initial code.
This may be backported to 2.4.
When a variable starts with the wrong scope, it is named without stripping
the extra characters that follow it, which usually are closing parenthesis.
Let's make sure we only report what is expected.
This may be backported to 2.4.
In commit 9a621ae76 ("MEDIUM: vars: add a new "set-var-fmt" action")
we introduced the support for format strings in variables with the
ability to release them on exit, except that it's the wrong list that
was being scanned for the rule (http vs vars), resulting in random
crashes during deinit.
This was a recent commit in 2.5-dev, no backport is needed.
The set-var() action is convenient because it preserves the input type
but it's a pain to deal with when trying to concatenate values. The
most recurring example is when it's needed to build a variable composed
of the source address and the source port. Usually it ends up like this:
tcp-request session set-var(sess.port) src_port
tcp-request session set-var(sess.addr) src,concat(":",sess.port)
This is even worse when trying to aggregate multiple fields from stick-table
data for example. Due to this a lot of users instead abuse headers from HTTP
rules:
http-request set-header(x-addr) %[src]:%[src_port]
But this requires some careful cleanups to make sure they won't leak, and
it's significantly more expensive to deal with. And generally speaking it's
not clean. Plus it must be performed for each and every request, which is
expensive for this common case of ip+port that doesn't change for the whole
session.
This patch addresses this limitation by implementing a new "set-var-fmt"
action which performs the same work as "set-var" but takes a format string
in argument instead of an expression. This way it becomes pretty simple to
just write:
tcp-request session set-var-fmt(sess.addr) %[src]:%[src_port]
It is usable in all rulesets that already support the "set-var" action.
It is not yet implemented for the global "set-var" directive (which already
takes a string) and the CLI's "set var" command, which would definitely
benefit from it but currently uses its own parser and engine, thus it
must be reworked.
The doc and regtests were updated.
There is a massive abuse of copy-paste in the doc that is visible in
the examples and arguments declaration. Let's at least remove irrelevant
examples for now.
When the expression called in "set-var" uses argments that require late
resolution, the context must be set. At the moment, any unknown argument
is misleadingly reported as "ACL":
frontend f
bind :8080
mode http
http-request set-var(proc.a) be_conn(foo)
parsing [b1.cfg:4]: unable to find backend 'foo' referenced in arg 1 \
of ACL keyword 'be_conn' in proxy 'f'.
Once the context is properly set, it now says the truth:
parsing [b1.cfg:8]: unable to find backend 'foo' referenced in arg 1 \
of sample fetch keyword 'be_conn' in http-request expression in proxy 'f'.
This may be backported but is not really important. If so, the preceeding
patches "BUG/MINOR: vars: improve accuracy of the rules used to check
expression validity" and "MINOR: sample: add missing ARGC_ entries" must
be backported as well.
For a long time we couldn't have arguments in expressions used in
tcp-request, tcp-response etc rules. But now due to the variables
it's possible, and their context in case of failure to resolve an
argument (e.g. backend name not found) is not properly reported
because there is no arg context values in ARGC_* to report them.
Let's add a number of missing ones for tcp-request {connection,
session,content}, tcp-response content, tcp-check, the config
parser (for "set-var" in the global section) and the CLI parser
(for "set-var" on the CLI).
The set-var() expression naturally checks whether expressions are valid
in the context of the rule, but it fails to differentiate frontends from
backends. As such for tcp-content and http-request rules, it will only
accept frontend-compatible sample-fetches, excluding those declared with
SMP_UES_BKEND (a few such as be_id, be_name). For the response it accepts
the backend-compatible expressions only, though it seems that there are
no sample-fetch function that are valid only in the frontend's content,
so that should not cause any problem.
Note that while allowing valid configs to be used, the fix might also
uncover some incorrect configurations where some expressions currently
return nothing (e.g. something depending on frontend declared in a
backend), and which could be rejected, but there does not seem to be
any such keyword. Thus while it should be backported, better not backport
it too far (2.4 and possibly 2.3 only).
The parser checks first for "set-var" then "unset-var" from the updated
offset instead of testing it only when the other one fails, so it
validates this rule as "unset-var":
http-request set-varunset-var(proc.a)
This should be backported everywhere relevant, though it's mostly harmless
as it's unlikely that some users are purposely writing this in their conf!
A recent update to BoringSSL broke the build again, and given that
it's not used except for QUIC development, let's temporarily disable
it until the issue is analysed and fixed.
Sometimes it is convenient to remap large sets of URIs to new ones (e.g.
after a site migration for example). This can be achieved using
"http-request redirect" combined with maps, but one difficulty there is
that non-matching entries will return an empty response. In order to
avoid this, duplicating the operation as an ACL condition ending in
"-m found" is possible but it becomes complex and error-prone while it's
known that an empty URL is not valid in a location header.
This patch addresses this by improving the redirect rules to be able to
simply ignore the rule and skip to the next one if the result of the
evaluation of the "location" expression is empty. However in order not
to break existing setups, it requires a new "ignore-empty" keyword.
There used to be an ACT_FLAG_FINAL on redirect rules that's used during
the parsing to emit a warning if followed by another rule, so here we
only set it if the option is not there. The http_apply_redirect_rule()
function now returns a 3rd value to mention that it did nothing and
that this was not an error, so that callers can just ignore the rule.
The regular "redirect" rules were not modified however since this does
not apply there.
The map_redirect VTC was completed with such a test and updated to 2.5
and an example was added into the documentation.
Those fetches are used to identify connection errors and SSL handshake
errors on the backend side of a connection. They can for instance be
used in a log-format line as in the regtest.
The bc_conn_err and bc_conn_err_str sample fetches give the status of
the connection on the backend side. The error codes and error messages
are the same than the ones that can be raised by the fc_conn_err fetch.
This new sample fetch along the ssl_bc_hsk_err_str fetch contain the
last SSL error of the error stack that occurred during the SSL
handshake (from the backend's perspective).
The locking in the dequeuing process was significantly improved by commit
49667c14b ("MEDIUM: queue: take the proxy lock only during the px queue
accesses") in that it tries hard to limit the time during which the
proxy's queue lock is held to the strict minimum. Unfortunately it's not
enough anymore, because we take up the task and manipulate a few pendconn
elements after releasing the proxy's lock (while we're under the server's
lock) but the task will not necessarily hold the server lock since it may
not have successfully found one (e.g. timeout in the backend queue). As
such, stream_free() calling pendconn_free() may release the pendconn
immediately after the proxy's lock is released while the other thread
currently proceeding with the dequeuing tries to wake up the owner's
task and dies in task_wakeup().
One solution consists in releasing le proxy's lock later. But tests have
shown that we'd have to sacrifice a significant share of the performance
gained with the patch above (roughly a 20% loss).
This patch takes another approach. It adds a "del_lock" to each pendconn
struct, that allows to keep it referenced while the proxy's lock is being
released. It's mostly a serialization lock like a refcount, just to maintain
the pendconn alive till the task_wakeup() call is complete. This way we can
continue to release the proxy's lock early while keeping this one. It had
to be added to the few points where we're about to free a pendconn, namely
in pendconn_dequeue() and pendconn_unlink(). This way we continue to
release the proxy's lock very early and there is no performance degradation.
This lock may only be held under the queue's lock to prevent lock
inversion.
No backport is needed since the patch above was merged in 2.5-dev only.
This option can be used to define a specific log format that will be
used in case of error, timeout, connection failure on a frontend... It
will be used for any log line concerned by the log-separate-errors
option. It will also replace the format of specific error messages
decribed in section 8.2.6.
If no "error-log-format" is defined, the legacy error messages are still
emitted and the other error logs keep using the regular log-format.
This option will be replaced by a "error-log-format" that enables to use
a dedicated log-format for connection error messages instead of the
regular log-format (in which most of the fields would be invalid in such
a case).
The "log-error-via-logformat" mechanism will then be replaced by a test
on the presence of such an error log format or not. If a format is
defined, it is used for connection error messages, otherwise the legacy
error log format is used.
As seen in issue #1369, supporting #if with unknown macros can silently
hide typos that may result in suboptimal code paths to be used, or even
possibly bugs. It looks like our code base does not rely that much on
this, so it's worth enabling -Wundef to catch future ones and have them
turned to more explicit "#if defined()" or #ifdef.
One was in backend.c and the other one in hlua.c. No other candidate
was found with "git grep '^#if\s*USE'". It's worth noting that 3
other such tests exist for SSL_OP_NO_{SSLv3,TLSv1_1,TLSv1_2} but
that these ones are properly set to 0 in openssl-compat.h when not
defined.
