Previously, when the client address was changed to the one from
the PROXY protocol header, the client port ($remote_port) was
reset to zero. Now the client port is also changed to the one
from the PROXY protocol header.
Since 4fbef397c753 nginx rejects with the 400 error any attempts of
requesting different host over the same connection, if the relevant
virtual server requires verification of a client certificate.
While requesting hosts other than negotiated isn't something legal
in HTTP/1.x, the HTTP/2 specification explicitly permits such requests
for connection reuse and has introduced a special response code 421.
According to RFC 7540 Section 9.1.2 this code can be sent by a server
that is not configured to produce responses for the combination of
scheme and authority that are included in the request URI. And the
client may retry the request over a different connection.
Now this code is used for requests that aren't authorized in current
connection. After receiving the 421 response a client will be able
to open a new connection, provide the required certificate and retry
the request.
Unfortunately, not all clients currently are able to handle it well.
Notably Chrome just shows an error, while at least the latest version
of Firefox retries the request over a new connection.
OpenSSL 1.0.2+ allows configuring a curve list instead of a single curve
previously supported. This allows use of different curves depending on
what client supports (as available via the elliptic_curves extension),
and also allows use of different curves in an ECDHE key exchange and
in the ECDSA certificate.
The special value "auto" was introduced (now the default for ssl_ecdh_curve),
which means "use an internal list of curves as available in the OpenSSL
library used". For versions prior to OpenSSL 1.0.2 it maps to "prime256v1"
as previously used. The default in 1.0.2b+ prefers prime256v1 as well
(and X25519 in OpenSSL 1.1.0+).
As client vs. server preference of curves is controlled by the
same option as used for ciphers (SSL_OP_CIPHER_SERVER_PREFERENCE),
the ssl_prefer_server_ciphers directive now controls both.
Both minor and major versions are now limited to 999 maximum. In case of
r->http_minor, this limit is already implied by the code. Major version,
r->http_major, in theory can be up to 65535 with current code, but such
values are very unlikely to become real (and, additionally, such values
are not allowed by RFC 7230), so the same test was used for r->http_major.
When it's known that the kernel supports EPOLLRDHUP, there is no need in
additional recv() call to get EOF or error when the flag is absent in the
event generated by the kernel. A special runtime test is done at startup
to detect if EPOLLRDHUP is actually supported by the kernel because
epoll_ctl() silently ignores unknown flags.
With this knowledge it's now possible to drop the "ready" flag for partial
read. Previously, the "ready" flag was kept until the recv() returned EOF
or error. In particular, this change allows the lingering close heuristics
(which relies on the "ready" flag state) to actually work on Linux, and not
wait for more data in most cases.
The "available" flag is now used in the read event with the semantics similar
to the corresponding counter in kqueue.
This parameter lets binding the proxy connection to a non-local address.
Upstream will see the connection as coming from that address.
When used with $remote_addr, upstream will accept the connection from real
client address.
Example:
proxy_bind $remote_addr transparent;
The WINDOW_UPDATE frame could be left in the output queue for an indefinite
period of time resulting in the request timeout.
This might happen if reading of the body was triggered by an event unrelated
to client connection, e.g. by the limit_req timer.
Particularly this prevents sending WINDOW_UPDATE with zero delta
which can result in PROTOCOL_ERROR.
Also removed surplus setting of no_flow_control to 0.
Refusing streams is known to be incorrectly handled at least by IE, Edge
and Safari. Make sure to provide appropriate logging to simplify fixing
this in the affected browsers.
After the 92464ebace8e change, it has been discovered that not all
clients follow the RFC and handle RST_STREAM with NO_ERROR properly.
Notably, Chrome currently interprets it as INTERNAL_ERROR and discards
the response.
As a workaround, instead of RST_STREAM the maximum stream window update
will be sent, which will let client to send up to 2 GB of a request body
data before getting stuck on flow control. All the received data will
be silently discarded.
See for details:
http://mailman.nginx.org/pipermail/nginx-devel/2016-April/008143.htmlhttps://bugs.chromium.org/p/chromium/issues/detail?id=603182
A client is allowed to send requests before receiving and acknowledging
the SETTINGS frame. Such a client having a wrong idea about the stream's
could send the request body that nginx isn't ready to process.
The previous behavior was to send RST_STREAM with FLOW_CONTROL_ERROR in
such case, but it didn't allow retrying requests that have been rejected.
This prevents forming empty records out of such buffers. Particularly it fixes
double end-of-stream records with chunked transfer encoding, or when HTTP/2 is
used and the END_STREAM flag has been sent without data. In both cases there
is an empty buffer at the end of the request body chain with the "last_buf"
flag set.
The canonical libfcgi, as well as php implementation, tolerates such records,
while the HHVM parser is more strict and drops the connection (ticket #950).
There are two improvements:
1. Support for request body filters;
2. Receiving of request body is started only after
the ngx_http_read_client_request_body() call.
The last one fixes the problem when the client_max_body_size value might not be
respected from the right location if the location was changed either during the
process of receiving body or after the whole body had been received.
RFC 7540 states that "A server can send a complete response prior to the client
sending an entire request if the response does not depend on any portion of the
request that has not been sent and received. When this is true, a server MAY
request that the client abort transmission of a request without error by sending
a RST_STREAM with an error code of NO_ERROR after sending a complete response
(i.e., a frame with the END_STREAM flag)."
This should prevent a client from blocking on the stream window, since it isn't
maintained for closed streams. Currently, quite big initial stream windows are
used, so such blocking is very unlikly, but that will be changed in the further
patches.
By default, requests with non-idempotent methods (POST, LOCK, PATCH)
are no longer retried in case of errors if a request was already sent
to a backend. Previous behaviour can be restored by using
"proxy_next_upstream ... non_idempotent".
Much like normal connections, cached connections are now tested against
u->conf->next_upstream, and u->state->status is now always set.
This allows to disable additional tries even with upstream keepalive
by using "proxy_next_upstream off".
When a keys_zone is full then each next request to the cache is
penalized. That is, the cache has to evict older files to get a
slot from the keys_zone synchronously. The patch introduces new
behavior in this scenario. Manager will try to maintain available
free slots in the keys_zone by cleaning old files in the background.
The "aio_write" directive is introduced, which enables use of aio
for writing. Currently it is meaningful only with "aio threads".
Note that aio operations can be done by both event pipe and output
chain, so proper mapping between r->aio and p->aio is provided when
calling ngx_event_pipe() and in output filter.
In collaboration with Valentin Bartenev.
This simplifies the interface of the ngx_thread_read() function.
Additionally, most of the thread operations now explicitly set
file->thread_task, file->thread_handler and file->thread_ctx,
to facilitate use of thread operations in other places.
(Potential problems remain with sendfile in threads though - it uses
file->thread_handler as set in ngx_output_chain(), and it should not
be overwritten to an incompatible one.)
In collaboration with Valentin Bartenev.
