log format expressions are broadly used within the code: once they are
parsed from input string, they are converted to a linked list of
logformat nodes.
We're starting to face some limitations because we're simply storing the
converted expression as a generic logformat_node list.
The first issue we're facing is that storing logformat expressions that
way doesn't allow us to add metadata alongside the list, which is part
of the prerequites for implementing log-profiles.
Another issue with storing logformat expressions as generic lists of
logformat_node elements is that it's starting to become really hard to
tell when we rely on logformat expressions or not in the code given that
there isn't always a comment near the list declaration or manipulation
to indicate that it's relying on logformat expressions under the hood,
so this adds some complexity for code maintenance.
This patch looks quite impressive due to changes in a lot of header and
source files (since logformat expressions are broadly used), but it does
a simple thing: it defines the lf_expr structure which itself holds a
generic list of logformat nodes, and then declares some helpers to
manipulate lf_expr elements and fixes the code so that we now exclusively
manipulate logformat_node lists as lf_expr elements outside of log.c.
For now, lf_expr struct only contains the list of logformat nodes (no
additional metadata), but now that we have dedicated type and helpers,
doing so in the future won't be problematic at all and won't require
extensive code changes.
Several places reuse the same code to ensure a connection is properly
freed, either via its MUX or by calling the proper set of functions.
Factorize all of this in a new function conn_release().
This new function is now called via session_free() and
session_accept_fd(). It will also be reused on delete server to
proactively close idle connections.
A server can only be deleted if there is no elements which reference it.
This is taken care via srv_check_for_deletion(), most notably for active
and idle connections.
A special case occurs for connections directly managed by a session.
This is for so-called private connections, when using http-reuse never
or H2 + http-reuse safe for example. In this case. server does not
account these connections into its idle lists. This caused a bug as the
server is deleted despite the session still being able to access it.
To properly fix this, add a new referencing element into the server for
these session connections. A mt_list has been chosen for this. On
default http-reuse, private connections are typically not used so it
won't make any difference. If using H2 servers, or more generally when
dealing with private connections, insert/delete should typically occur
only once per session lifetime so impact on performance should be
minimal.
This should be backported up to 2.4. Note that srv_check_for_deletion()
was introduced in 3.0 dev tree. On backport, the extra condition in it
should be placed in cli_parse_delete_server() instead.
By default, backend connections are attached to a server instance. This
allows to implement connection reuse. However, in some particular cases,
connection cannot be shared accross several clients. These connections
are considered and private and are attached to the session instance
instead.
These private connections are also indexed by the target server to not
mix them. All of this is implemented via a dedicated structure
previously named struct sess_srv_list.
Rename it to better reflect its usage to struct sess_priv_conns. Also
rename its internal members and all of the associated functions.
This commit is only a renaming, thus no functional impact is expected.
Adapt session_accept_fd() called on accept() to set the handshake timeout from
"hanshake-timeout" setting if set by configuration. If not set, continue to use
the "client" timeout setting.
When an active reverse connection is initialized, it has no stream-conn
attached to it contrary to other backend connections. This forces to add
extra check on stream existence in conn_create_mux() and h2_init().
There is also extra checks required for session_accept_fd() after
reverse and accept is done. This is because contrary to other frontend
connections, reversed connections have already initialized their mux and
transport layers. This forces us to skip the majority of
session_accept_fd() initialization part.
Finally, if session_accept_fd() is interrupted due to an early error, a
reverse connection cannot be freed directly or else mux will remain
alone. Instead, the mux destroy callback is used to free all connection
elements properly.
It was reported in issue #2181, strange behavior during the new SSL
hanshake failure logs.
Errors were logged with the code 0, which is unknown to OpenSSL.
This patch mades 2 changes:
- It stops using ERR_error_string() when the SSL error code is 0
- It uses ERR_error_string_n() to be thread-safe
Must be backported to 2.8.
SSL hanshake error were unable to dump the OpenSSL error string by
default, to do so it was mandatory to configure a error-log-format with
the ssl_fc_err fetch.
This patch implements the session_build_err_string() function which creates
the error log to send during session_kill_embryonic(), a special case is
made with CO_ER_SSL_HANDSHAKE which is able to dump the error string
with ERR_error_string().
Before:
<134>May 12 17:14:04 haproxy[183151]: 127.0.0.1:49346 [12/May/2023:17:14:04.571] frt2/1: SSL handshake failure
After:
<134>May 12 17:14:04 haproxy[183151]: 127.0.0.1:49346 [12/May/2023:17:14:04.571] frt2/1: SSL handshake failure (error:0A000418:SSL routines::tlsv1 alert unknown ca)
This puts an end to the occasional confusion between the "now" date
that is internal, monotonic and not synchronized with the system's
date, and "date" which is the system's date and not necessarily
monotonic. Variable "now" was removed and replaced with a 64-bit
integer "now_ns" which is a counter of nanoseconds. It wraps every
585 years, so if all goes well (i.e. if humanity does not need
haproxy anymore in 500 years), it will just never wrap. This implies
that now_ns is never nul and that the zero value can reliably be used
as "not set yet" for a timestamp if needed. This will also simplify
date checks where it becomes possible again to do "date1<date2".
All occurrences of "tv_to_ns(&now)" were simply replaced by "now_ns".
Due to the intricacies between now, global_now and now_offset, all 3
had to be turned to nanoseconds at once. It's not a problem since all
of them were solely used in 3 functions in clock.c, but they make the
patch look bigger than it really is.
The clock_update_local_date() and clock_update_global_date() functions
are now much simpler as there's no need anymore to perform conversions
nor to round the timeval up or down.
The wrapping continues to happen by presetting the internal offset in
the short future so that the 32-bit now_ms continues to wrap 20 seconds
after boot.
The start_time used to calculate uptime can still be turned to
nanoseconds now. One interrogation concerns global_now_ms which is used
only for the freq counters. It's unclear whether there's more value in
using two variables that need to be synchronized sequentially like today
or to just use global_now_ns divided by 1 million. Both approaches will
work equally well on modern systems, the difference might come from
smaller ones. Better not change anyhting for now.
One benefit of the new approach is that we now have an internal date
with a resolution of the nanosecond and the precision of the microsecond,
which can be useful to extend some measurements given that timestamps
also have this resolution.
Let's get rid of timeval in storage of internal timestamps so that they
are no longer mistaken for wall clock time. These were exclusively used
subtracted from each other or to/from "now" after being converted to ns,
so this patch removes the tv_to_ns() conversion to use them natively. Two
occurrences of tv_isge() were turned to a regular wrapping subtract.
Instead of operating on {sec, usec} now we convert both operands to
ns then subtract them and convert to ms. This is a first step towards
dropping timeval from these timestamps.
Interestingly, tv_ms_elapsed() and tv_ms_remain() are no longer used at
all and could be removed.
Commit 0aba11e9e ("MINOR: quic: remove unnecessary quic_session_accept()")
overlooked one problem, in session_accept_fd() at the end, there's a bunch
of FD-specific stuff that either sets up or resets the socket at the TCP
level. The tests are mostly performed for AF_INET/AF_INET6 families but
they're only for one part (i.e. to avoid setting up TCP options on UNIX
sockets). Other pieces continue to configure the socket regardless of its
family. All of this directly acts on the FD, which is not correct since
the FD is not valid here, it corresponds to the QUIC handle. The issue
is much more visible when "option nolinger" is enabled in the frontend,
because the access to fdatb[cfd].state immediately crashes on the first
connection, as can be seen in github issue #2030.
This patch bypasses this setup for FD-less connections, such as QUIC.
However some of them could definitely be relevant to the QUIC stack, or
even to UNIX sockets sometimes. A better long-term solution would consist
in implementing a setsockopt() equivalent at the protocol layer that would
be used to configure the socket, either the FD or the QUIC conn depending
on the case. Some of them would not always be implemented but that would
allow to unify all this code.
This fix must be backported everywhere the commit above is backported,
namely 2.6 and 2.7.
Thanks to github user @twomoses for the nicely detailed report.
LI_O_TCP_L4_RULES and LI_O_TCP_L5_RULES are only set by from the proxy
based on the presence or absence of tcp_req l4/l5 rules. It's basically
as cheap to check the list as it is to check the flag, except that there
is no need to maintain a copy. Let's get rid of them, and this may ease
addition of more dynamic stuff later.
These are only set per bind line and used when creating a sessions,
we can move them to the bind_conf under the names BC_O_ACC_PROXY and
BC_O_ACC_CIP respectively.
These two arguments were only set and only used with tcpv4/tcpv6. Let's
just store them into the bind_conf instead of duplicating them for all
listeners since they're fixed per "bind" line.
The number of stick-counter entries usable by track-sc rules is currently
set at build time. There is no good value for this since the vast majority
of users don't need any, most need only a few and rare users need more.
Adding more counters for everyone increases memory and CPU usages for no
reason.
This patch moves the per-session and per-stream arrays to a pool of a size
defined at boot time. This way it becomes possible to set the number of
entries at boot time via a new global setting "tune.stick-counters" that
sets the limit for the whole process. When not set, the MAX_SESS_STR_CTR
value still applies, or 3 if not set, as before.
It is also possible to lower the value to 0 to save a bit of memory if
not used at all.
Note that a few low-level sample-fetch functions had to be protected due
to the ability to use sample-fetches in the global section to set some
variables.
Andrew Suffield reported in issue #1596 that we've had a bug in
session_accept_fd() since 2.4 with commit 1b3c931bf ("MEDIUM:
connections: Introduce a new XPRT method, start().") where an error
label is wrong and may cause the leak of the freshly allocated session
in case conn_xprt_start() returns < 0.
The code was checked there and the only two transport layers available
at this point are raw_sock and ssl_sock. The former doesn't provide a
->start() method hence conn_xprt_start() will always return zero. The
second does provide such a function, but it may only return <0 if the
underlying transport (raw_sock) has such a method and fails, which is
thus not the case.
So fortunately it is not possible to trigger this leak.
The patch above also touched the accept code in quic_sock() which was
mostly a plain copy of the session code, but there the move didn't
have this impact, and since then it was simplified and the next change
moved it to its final destination with the proper error label.
This should be backported as far as 2.4 as a long-term safety measure
(e.g. if in the future we have a reason for making conn_xprt_start()
to start failing), but will not have any positive nor negative effect
in the short term.
When an embryonic session is killed, if no log format is defined for this
error, a generic error is emitted. When this happens, we now rely on the
session to get the client source address. For now, session addresses are
never set. So, thanks to the fallback mechanism, no changes are expected
with this patch. But its purpose is to rely on addresses at the session
level when set instead of those at the connection level.
For now, these addresses are never set. But the idea is to be able to set
client source and destination addresses at the session level without
updating the connection ones.
Functions to fill these addresses have been added: sess_get_src() and
sess_get_dst(). If not already set, these functions relies on
conn_get_src() and conn_get_dst() to fill session addresses.
And just like for conncetions, sess_src() and sess_dst() may be used to get
source and destination addresses. However, if not set, the corresponding
address from the underlying client connection is returned. When this
happens, the addresses is filled in the connection object.
We'll need to improve the API to pass other arguments in the future, so
let's start to adapt better to the current use cases. task_new() is used:
- 18 times as task_new(tid_bit)
- 18 times as task_new(MAX_THREADS_MASK)
- 2 times with a single bit (in a loop)
- 1 in the debug code that uses a mask
This patch provides 3 new functions to achieve this:
- task_new_here() to create a task on the calling thread
- task_new_anywhere() to create a task to be run anywhere
- task_new_on() to create a task to run on a specific thread
The change is trivial and will allow us to later concentrate the
required adaptations to these 3 functions only. It's still possible
to call task_new() if needed but a comment was added to encourage the
use of the new ones instead. The debug code was not changed and still
uses it.
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.
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.
Rename the 'dontloglegacyconnerr' option to 'log-error-via-logformat'
which is much more self-explanatory and readable.
Note: only legacy keywords don't use hyphens, it is recommended to
separate words with them in new keywords.
In case of connection failure, a dedicated error message is output,
following the format described in section "Error log format" of the
documentation. These messages cannot be configured through a log-format
option.
This patch adds a new option, "dontloglegacyconnerr", that disables
those error logs when set, and "replaces" them by a regular log line
that follows the configured log-format (thanks to a call to sess_log in
session_kill_embryonic).
The new fc_conn_err sample fetch allows to add the legacy error log
information into a regular log format.
This new option is unset by default so the logging logic will remain the
same until this new option is used.
This patch replaces all advanced data type aliases on
stktable_data_cast calls by standard types.
This way we could call the same stktable_data_cast
regardless of the used advanced data type as long they
are using the same std type.
It also removes all the advanced data type aliases.
This patch replaces roughly all occurrences of an HA_ATOMIC_ADD(&foo, 1)
or HA_ATOMIC_SUB(&foo, 1) with the equivalent HA_ATOMIC_INC(&foo) and
HA_ATOMIC_DEC(&foo) respectively. These are 507 changes over 45 files.
No need to keep this flag apart any more, let's merge it into the global
state. The CLI's output state was extended to 6 digits and the linger/cloned
flags moved inside the parenthesis.
Introduce a new XPRT method, start(). The init() method will now only
initialize whatever is needed for the XPRT to run, but any action the XPRT
has to do before being ready, such as handshakes, will be done in the new
start() method. That way, we will be sure the full stack of xprt will be
initialized before attempting to do anything.
The init() call is also moved to conn_prepare(). There's no longer any reason
to wait for the ctrl to be ready, any action will be deferred until start(),
anyway. This means conn_xprt_init() is no longer needed.
It's been too short for quite a while now and is now full. It's still
time to extend it to 32-bits since we have room for this without
wasting any space, so we now gained 16 new bits for future flags.
The values were not reassigned just in case there would be a few
hidden u16 or short somewhere in which these flags are placed (as
it used to be the case with stream->pending_events).
The patch is tagged MEDIUM because this required to update the task's
process() prototype to use an int instead of a short, that's quite a
bunch of places.
In session_count_new() the tracked counter was still incremented with
a "++" outside of any lock, resulting in occasional slightly off values
such as the following:
# table: foo, type: string, size:1000, used:1
0xb2a398: key=127.1.2.3 use=0 exp=86398318 sess_cnt=999959 http_req_cnt=1000004
Now with the correct atomic increment:
# table: foo, type: string, size:1000, used:1
0x7f82a4026d38: key=127.1.2.3 use=0 exp=86399294 sess_cnt=1000004 http_req_cnt=1000004
This can be backported to 1.8.
The idle duration between two streams is added to the session structure. It
is not necessarily pertinent on all protocols. In fact, it is only defined
for H1 connections. It is the duration between two H1 transactions. But the
.get_cs_info() callback function on the multiplexers only exists because
this duration is missing at the session level. So it is a simplification
opportunity for a really low cost.
To reduce the cost, a hole in the session structure is filled by moving
.srv_list field at the end of the structure.
Baptiste reported a new crash affecting 2.3 which can be triggered
when using H2 on the backend, with http-reuse always and with a tens
of clients doing close only. There are a few combined cases which cause
this to happen, but each time the issue is the same, an already freed
session is dereferenced in session_unown_conn().
Two cases were identified to cause this:
- a connection referencing a session as its owner, which is detached
from the session's list and is destroyed after this session ends.
The test on conn->owner before calling session_unown_conn() is not
sufficent as the pointer is not null but is not valid anymore.
- a connection that never goes idle and that gets killed form the
mux, where session_free() is called first, then conn_free() calls
session_unown_conn() which scans the just freed session for older
connections. This one is only triggered with DEBUG_UAF
The reason for this session to be present here is that it's needed during
the connection setup, to be passed to conn_install_mux_be() to mux->init()
as the owning session, but it's never deleted aftrewards. Furthermore, even
conn_session_free() doesn't delete this pointer after freeing the session
that lies there. Both do definitely result in a use-after-free that's more
easily triggered under DEBUG_UAF.
This patch makes sure that the owner is always deleted after detaching
or killing the session. However it is currently not possible to clear
the owner right after a synchronous init because the proxy protocol
apparently needs it (a reg test checks this), and if we leave it past
the connection setup with the session not attached anywhere, it's hard
to catch the right moment to detach it. This means that the session may
remain in conn->owner as long as the connection has never been added to
nor removed from the session's idle list. Given that this patch needs to
remain simple enough to be backported, instead it adds a workaround in
session_unown_conn() to detect that the element is already not attached
anywhere.
This fix absolutely requires previous patch "CLEANUP: connection: do not
use conn->owner when the session is known" otherwise the situation will
be even worse, as some places used to rely on conn->owner instead of the
session.
The fix could theorically be backported as far as 1.8. However, the code
in this area has significantly changed along versions and there are more
risks of breaking working stuff than fixing real issues there. The issue
was really woken up in two steps during 2.3-dev when slightly reworking
the idle conns with commit 08016ab82 ("MEDIUM: connection: Add private
connections synchronously in session server list") and when adding
support for storing used H2 connections in the session and adding the
necessary call to session_unown_conn() in the muxes. But the same test
managed to crash 2.2 when built in DEBUG_UAF and patched like this,
proving that we used to already leave dangling pointers behind us:
| diff --git a/include/haproxy/connection.h b/include/haproxy/connection.h
| index f8f235c1a..dd30b5f80 100644
| --- a/include/haproxy/connection.h
| +++ b/include/haproxy/connection.h
| @@ -458,6 +458,10 @@ static inline void conn_free(struct connection *conn)
| sess->idle_conns--;
| session_unown_conn(sess, conn);
| }
| + else {
| + struct session *sess = conn->owner;
| + BUG_ON(sess && sess->origin != &conn->obj_type);
| + }
|
| sockaddr_free(&conn->src);
| sockaddr_free(&conn->dst);
It's uncertain whether an existing code path there can lead to dereferencing
conn->owner when it's bad, though certain suspicious memory corruption bugs
make one think it's a likely candidate. The patch should not be hard to
adapt there.
Backports to 2.1 and older are left to the appreciation of the person
doing the backport.
A reproducer consists in this:
global
nbthread 1
listen l
bind :9000
mode http
http-reuse always
server s 127.0.0.1:8999 proto h2
frontend f
bind :8999 proto h2
mode http
http-request return status 200
Then this will make it crash within 2-3 seconds:
$ h1load -e -r 1 -c 10 http://0:9000/
If it does not, it might be that DEBUG_UAF was not used (it's harder then)
and it might be useful to restart.
Now that this function is always called with an initialized connection
and that the control layer is always initialized, we don't need to play
games with fdtab[] to decide how to close, we can simply rely on the
regular close path using conn_ctrl_close(), which can be fused with
conn_xprt_close() into conn_full_close().
The code is cleaner because the FD is now used only for some
protocol-specific setup (that will eventually have to move) and to
try to send a hard-coded HTTP 500 error message on raw sockets.
Till now we would keep a per-thread queue of pending incoming connections
for which we would store:
- the listener
- the accepted FD
- the source address
- the source address' length
And these elements were first used in session_accept_fd() running on the
target thread to allocate a connection and duplicate them again. Doing
this induces various problems. The first one is that session_accept_fd()
may only run on file descriptors and cannot be reused for QUIC. The second
issue is that it induces lots of memory copies and that the listerner
queue thrashes a lot of cache, consuming 64 bytes per entry.
This patch changes this by allocating the connection before queueing it,
and by only placing the connection's pointer into the queue. Indeed, the
first two calls used to initialize the connection already store all the
information above, which can be retrieved from the connection pointer
alone. So we just have to pop one pointer from the target thread, and
pass it to session_accept_fd() which only needs the FD for the final
settings.
This starts to make the accept path a bit more transport-agnostic, and
saves memory and CPU cycles at the same time (1% connection rate increase
was noticed with 4 threads). Thanks to dividing the accept-queue entry
size from 64 to 8 bytes, its size could be increased from 256 to 1024
connections while still dividing the overall size by two. No single
queue full condition was met.
One minor drawback is that connection may be allocated from one thread's
pool to be used into another one. But this already happens a lot with
connection reuse so there is really nothing new here.
Roughly half of the calls to sockadr_alloc() are made to copy an already
known address. Let's optionally pass it in argument so that the function
can handle the copy at the same time, this slightly simplifies its usage.
As discussed here during 2.1-dev, "monitor-net" is totally obsolete:
https://www.mail-archive.com/haproxy@formilux.org/msg35204.html
It's fundamentally incompatible with usage of SSL, and imposes the
presence of file descriptors with hard-coded syscalls directly in the
generic accept path.
It's very unlikely that anyone has used it in the last 10 years for
anything beyond testing. In the worst case if anyone would depend
on it, replacing it with "http-request return status 200 if ..." and
"mode http" would certainly do the trick.
The keyword is still detected as special by the config parser to help
users update their configurations appropriately.
As discussed here during 2.1-dev, "mode health" is totally obsolete:
https://www.mail-archive.com/haproxy@formilux.org/msg35204.html
It's fundamentally incompatible with usage of SSL, doesn't support
source filtering, and imposes the presence of file descriptors with
hard-coded syscalls directly in the generic accept path.
It's very unlikely that anyone has used it in the last 10 years for
anything beyond testing. In the worst case if anyone would depend
on it, replacing it with "http-request return status 200" and "mode
http" would certainly do the trick.
The keyword is still detected as special by the config parser to help
users update their configurations appropriately.
Some socket settings used to be retrieved via the listener and the
bind_conf. Now instead we use the receiver and its settings whenever
appropriate. This will simplify the removal of the dependency on the
listener.
The receiver is the one which depends on the protocol while the listener
relies on the receiver. Let's move the protocol there. Since there's also
a list element to get back to the listener from the proto list, this list
element (proto_list) was moved as well. For now when scanning protos, we
still see listeners which are linked by their rx.proto_list part.
The netns is common to all listeners/receivers and is used to bind the
listening socket so it must be in the receiver settings and not in the
listener. This removes some yet another set of unnecessary loops.
When a new connection is created, its target is always set just after. So the
connection target may set when it is created instead, during its initialisation
to be precise. It is the purpose of this patch. Now, conn_new() function is
called with the connection target as parameter. The target is then passed to
conn_init(). It means the target must be passed when cs_new() is called. In this
case, the target is only used when the conn-stream is created with no
connection. This only happens for tcpchecks for now.
Previous commit b24bc0d ("MINOR: tcp: Support TCP keepalive parameters
customization") broke non-Linux builds as TCP_KEEP{CNT,IDLE,INTVL} are
not necessarily defined elsewhere.
This patch adds the required #ifdefs to condition the visibility of the
keywords, and adds a mention in the doc about their dependency on Linux.
It is now possible to customize TCP keepalive parameters.
These correspond to the socket options TCP_KEEPCNT, TCP_KEEPIDLE, TCP_KEEPINTVL
and are valid for the defaults, listen, frontend and backend sections.
This patch fixes GitHub issue #670.
