This is expected to help with clients using pipelining with some constant
depth, such as apt[1][2].
When downloading many resources, apt uses pipelining with some constant
depth, a number of requests in flight. This essentially means that after
receiving a response it sends an additional request to the server, and
this can result in requests arriving to the server at any time. Further,
additional requests are sent one-by-one, and can be easily seen as such
(neither as pipelined, nor followed by pipelined requests).
The only safe approach to close such connections (for example, when
keepalive_requests is reached) is with lingering. To do so, now nginx
monitors if pipelining was used on the connection, and if it was, closes
the connection with lingering.
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=973861#10
[2] https://mailman.nginx.org/pipermail/nginx-devel/2023-January/ZA2SP5SJU55LHEBCJMFDB2AZVELRLTHI.html
Since 4611:2b6cb7528409 responses from the gzip static, flv, and mp4 modules
can be used with subrequests, though empty files were not properly handled.
Empty gzipped, flv, and mp4 files thus resulted in "zero size buf in output"
alerts. While valid corresponding files are not expected to be empty, such
files shouldn't result in alerts.
Fix is to set b->sync on such empty subrequest responses, similarly to what
ngx_http_send_special() does.
Additionally, the static module, the ngx_http_send_response() function, and
file cache are modified to do the same instead of not sending the response
body at all in such cases, since not sending the response body at all is
believed to be at least questionable, and might break various filters
which do not expect such behaviour.
The "listen" directive in the http module can be used multiple times
in different server blocks. Originally, it was supposed to be specified
once with various socket options, and without any parameters in virtual
server blocks. For example:
server { listen 80 backlog=1024; server_name foo; ... }
server { listen 80; server_name bar; ... }
server { listen 80; server_name bazz; ... }
The address part of the syntax ("address[:port]" / "port" / "unix:path")
uniquely identifies the listening socket, and therefore is enough for
name-based virtual servers (to let nginx know that the virtual server
accepts requests on the listening socket in question).
To ensure that listening options do not conflict between virtual servers,
they were allowed only once. For example, the following configuration
will be rejected ("duplicate listen options for 0.0.0.0:80 in ..."):
server { listen 80 backlog=1024; server_name foo; ... }
server { listen 80 backlog=512; server_name bar; ... }
At some point it was, however, noticed, that it is sometimes convenient
to repeat some options for clarity. In nginx 0.8.51 the "ssl" parameter
was allowed to be specified multiple times, e.g.:
server { listen 443 ssl backlog=1024; server_name foo; ... }
server { listen 443 ssl; server_name bar; ... }
server { listen 443 ssl; server_name bazz; ... }
This approach makes configuration more readable, since SSL sockets are
immediately visible in the configuration. If this is not needed, just the
address can still be used.
Later, additional protocol-specific options similar to "ssl" were
introduced, notably "http2" and "proxy_protocol". With these options,
one can write:
server { listen 443 ssl backlog=1024; server_name foo; ... }
server { listen 443 http2; server_name bar; ... }
server { listen 443 proxy_protocol; server_name bazz; ... }
The resulting socket will use ssl, http2, and proxy_protocol, but this
is not really obvious from the configuration.
To emphasize such misleading configurations are discouraged, nginx now
warns as long as the "listen" directive is used with options different
from the options previously used if this is potentially confusing.
In particular, the following configurations are allowed:
server { listen 8401 ssl backlog=1024; server_name foo; }
server { listen 8401 ssl; server_name bar; }
server { listen 8401 ssl; server_name bazz; }
server { listen 8402 ssl http2 backlog=1024; server_name foo; }
server { listen 8402 ssl; server_name bar; }
server { listen 8402 ssl; server_name bazz; }
server { listen 8403 ssl; server_name bar; }
server { listen 8403 ssl; server_name bazz; }
server { listen 8403 ssl http2; server_name foo; }
server { listen 8404 ssl http2 backlog=1024; server_name foo; }
server { listen 8404 http2; server_name bar; }
server { listen 8404 http2; server_name bazz; }
server { listen 8405 ssl http2 backlog=1024; server_name foo; }
server { listen 8405 ssl http2; server_name bar; }
server { listen 8405 ssl http2; server_name bazz; }
server { listen 8406 ssl; server_name foo; }
server { listen 8406; server_name bar; }
server { listen 8406; server_name bazz; }
And the following configurations will generate warnings:
server { listen 8501 ssl http2 backlog=1024; server_name foo; }
server { listen 8501 http2; server_name bar; }
server { listen 8501 ssl; server_name bazz; }
server { listen 8502 backlog=1024; server_name foo; }
server { listen 8502 ssl; server_name bar; }
server { listen 8503 ssl; server_name foo; }
server { listen 8503 http2; server_name bar; }
server { listen 8504 ssl; server_name foo; }
server { listen 8504 http2; server_name bar; }
server { listen 8504 proxy_protocol; server_name bazz; }
server { listen 8505 ssl http2 proxy_protocol; server_name foo; }
server { listen 8505 ssl http2; server_name bar; }
server { listen 8505 ssl; server_name bazz; }
server { listen 8506 ssl http2; server_name foo; }
server { listen 8506 ssl; server_name bar; }
server { listen 8506; server_name bazz; }
server { listen 8507 ssl; server_name bar; }
server { listen 8507; server_name bazz; }
server { listen 8507 ssl http2; server_name foo; }
server { listen 8508 ssl; server_name bar; }
server { listen 8508; server_name bazz; }
server { listen 8508 ssl backlog=1024; server_name foo; }
server { listen 8509; server_name bazz; }
server { listen 8509 ssl; server_name bar; }
server { listen 8509 ssl backlog=1024; server_name foo; }
The basic idea is that at most two sets of protocol options are allowed:
the main one (with socket options, if any), and a shorter one, with options
being a subset of the main options, repeated for clarity. As long as the
shorter set of protocol options is used, all listen directives except the
main one should use it.
Previously, location prefix length in ngx_http_location_tree_node_t was
stored as "u_char", and therefore location prefixes longer than 255 bytes
were handled incorrectly.
Fix is to use "u_short" instead. With "u_short", prefixes up to 65535 bytes
can be safely used, and this isn't reachable due to NGX_CONF_BUFFER, which
is 4096 bytes.
In contrast to on-the-fly gzipping with gzip filter, static gzipped
representation as returned by gzip_static is persistent, and therefore
the same binary representation is available for future requests, making
it possible to use range requests.
Further, if a gzipped representation is re-generated with different
compression settings, it is expected to result in different ETag and
different size reported in the Content-Range header, making it possible
to safely use range requests anyway.
As such, ranges are now allowed for files returned by gzip_static.
Ports difference must be respected when checking addresses for duplicates,
otherwise configurations like this are broken:
listen 127.0.0.1:6000-6005
It was broken by 4cc2bfeff46c (nginx 1.23.3).
Fixed event flags handling edge cases in ngx_wsarecv() and ngx_wsarecv_chain(),
notably to always reset rev->ready in case of errors (which wasn't the case
after ngx_socket_nread() errors), and after EOF (rev->ready was not cleared
if due to a misconfiguration a zero-sized buffer was used for reading).
With this change, behaviour of ngx_ssl_recv() now matches ngx_unix_recv(),
which used to always reset c->read->ready to 0 when returning errors.
This fixes an infinite loop in unbuffered SSL proxying if writing to the
client is blocked and an SSL error happens (ticket #2418).
With this change, the fix for a similar issue in the stream module
(6868:ee3645078759), which used a different approach of explicitly
testing c->read->error instead, is no longer needed and was reverted.
Casts are believed to be not needed, since memcmp() has "const void *"
arguments since introduction of the "void" type in C89. And on pre-C89
platforms nginx is unlikely to compile without warnings anyway, as there
are no casts in memcpy() and memmove() calls.
These casts were added in 1648:89a47f19b9ec without any details on why they
were added, and Igor does not remember details either. The most plausible
explanation is that they were copied from ngx_strcmp() and were not really
needed even at that time.
Prodded by Alejandro Colomar.
Binary upgrades are not supported without master process, but it is,
however, possible, that nginx running with master process is asked
to upgrade binary, and the configuration file as available on disk
at this time includes "master_process off;".
If this happens, listening sockets inherited from the previous binary
will have ls[i].previous set. But the old cycle on initial process
startup, including startup after binary upgrade, is destroyed by
ngx_init_cycle() once configuration parsing is complete. As a result,
an attempt to dereference ls[i].previous in ngx_event_process_init()
accesses already freed memory.
Fix is to avoid looking into ls[i].previous if the old cycle is already
freed.
With this change it is also no longer needed to clear ls[i].previous in
worker processes, so the relevant code was removed.
Cloning of listening sockets for each worker process does not make sense
when working without master process, and causes some of the connections
not to be accepted if worker_processes is set to more than one and there
are listening sockets configured with the reuseport flag. Fix is to
disable cloning when master process is disabled.
Due to the glibc bug[1], getaddrinfo("localhost") with AI_ADDRCONFIG
on a typical host with glibc and without IPv6 returns two 127.0.0.1
addresses, and therefore "listen localhost:80;" used to result in
"duplicate ... address and port pair" after 4f9b72a229c1.
Fix is to explicitly filter out duplicate addresses returned during
resolution of a name.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=14969
Previously, if an event was posted by a read event handler, called by
ngx_close_idle_connections(), that event was not processed until the next
event loop iteration, which could happen after a timeout.
As the SSI parser always uses the context from the main request for storing
variables and blocks, that context should always exist for subrequests using
SSI, even though the main request does not necessarily have SSI enabled.
However, `ngx_http_get_module_ctx(r->main, ...)` is getting NULL in such cases,
resulting in the worker crashing SIGSEGV when accessing its attributes.
This patch links the first initialized context to the main request, and
upgrades it only when main context is initialized.
The check is not expected to fail unless there is a bug in the calling
code. But given the check is here, it should log an alert if it fails
instead of silently closing the connection.
Maximum size for reading the PROXY protocol header is increased to 4096 to
accommodate a bigger number of TLVs, which are supported since cca4c8a715de.
Maximum size for writing the PROXY protocol header is not changed since only
version 1 is currently supported.
Most atoms should not appear more than once in a container. Previously,
this was not enforced by the module, which could result in worker process
crash, memory corruption and disclosure.
Now it properly detects invalid shared zone configuration with omitted size.
Previously it used to read outside of the buffer boundary.
Found with AddressSanitizer.
OpenSSL with TLSv1.3 updates the session creation time on session
resumption and keeps the session timeout unmodified, making it possible
to maintain the session forever, bypassing client certificate expiration
and revocation. To make sure session timeouts are actually used, we
now update the session creation time and reduce the session timeout
accordingly.
BoringSSL with TLSv1.3 ignores configured session timeouts and uses a
hardcoded timeout instead, 7 days. So we update session timeout to
the configured value as soon as a session is created.
Instead of syncing keys with shared memory on each ticket operation,
the code now does this only when the worker is going to change expiration
of the current key, or going to switch to a new key: that is, usually
at most once per second.
To do so without races, the code maintains 3 keys: current, previous,
and next. If a worker will switch to the next key earlier, other workers
will still be able to decrypt new tickets, since they will be encrypted
with the next key.
As long as ssl_session_cache in shared memory is configured, session ticket
keys are now automatically generated in shared memory, and rotated
periodically. This can be beneficial from forward secrecy point of view,
and also avoids increased CPU usage after configuration reloads.
This also helps BoringSSL to properly resume sessions in configurations
with multiple worker processes and no ssl_session_ticket_key directives,
as BoringSSL tries to automatically rotate session ticket keys and does
this independently in different worker processes, thus breaking session
resumption between worker processes.
Given the present typical SSL session sizes, on 32-bit platforms it is
now beneficial to store all data in a single allocation, since rbtree
node + session id + ASN1 representation of a session takes 256 bytes of
shared memory (36 + 32 + 150 = about 218 bytes plus SNI server name).
Storing all data in a single allocation is beneficial for SNI names up to
about 40 characters long and makes it possible to store about 4000 sessions
in one megabyte (instead of about 3000 sessions now). This also slightly
simplifies the code.
Session ids are not expected to be longer than 32 bytes, but this is
theoretically possible with TLSv1.3, where session ids are essentially
arbitrary and sent as session tickets. Since on 64-bit platforms we
use fixed 32-byte buffer for session ids, added an explicit length check
to make sure the buffer is large enough.
Session cache allocations might fail as long as the new session is different
in size from the one least recently used (and freed when the first allocation
fails). In particular, it might not be possible to allocate space for
sessions with client certificates, since they are noticeably bigger than
normal sessions.
To ensure such allocation failures won't clutter logs, logging level changed
to "warn", and logging is now limited to at most one warning per second.
OpenSSL tries to save TLSv1.3 sessions into session cache even when using
tickets for stateless session resumption, "because some applications just
want to know about the creation of a session". To avoid trashing session
cache with useless data, we do not save such sessions now.
The variables have prefix $proxy_protocol_tlv_ and are accessible by name
and by type. Examples are: $proxy_protocol_tlv_0x01, $proxy_protocol_tlv_alpn.
Previously, all received user input was logged. If a multi-line text was
received from client and logged, it could reduce log readability and also make
it harder to parse nginx log by scripts. The change brings to PROXY protocol
the same behavior that exists for HTTP request line in
ngx_http_log_error_handler().
