Previously, when a buffer was processed by the sub filter, its final bytes
could be buffered by the filter even if they don't match any pattern.
This happened because the Boyer-Moore algorithm, employed by the sub filter
since b9447fc457b4 (1.9.4), matches the last characters of patterns prior to
checking other characters. If the last character is out of scope, initial
bytes of a potential match are buffered until the last character is available.
Now, after receiving a flush or recycled buffer, the filter performs
additional checks to reduce the number of buffered bytes. The potential match
is checked against the initial parts of all patterns. Non-matching bytes are
not buffered. This improves processing of a chunked response from upstream
by sending the entire chunks without buffering unless a partial match is found
at the end of a chunk.
This reduces the number of moving parts in ABI compatibility checks.
Additionally, it also allows to use OpenSSL in FIPS mode while still
using md5 for non-security tasks.
The option is only set if the socket is bound to a specific port to allow
several such sockets coexist at the same time. This is required, for example,
when nginx acts as a transparent proxy and receives two datagrams from the same
client in a short time.
The feature is only implemented for Linux.
The following two types of bind addresses are supported in addition to
$remote_addr and address literals:
- $remote_addr:$remote_port
- [$remote_addr]:$remote_port
In both cases client remote address with port is used in upstream socket bind.
This patch moves various OpenSSL-specific function calls into the
OpenSSL module and introduces ngx_ssl_ciphers() to make nginx more
crypto-library-agnostic.
When the stream is terminated the HEADERS frame can still wait in the output
queue. This frame can't be removed and must be sent to the client anyway,
since HTTP/2 uses stateful compression for headers. So in order to postpone
closing and freeing memory of such stream the special close stream handler
is set to the write event. After the HEADERS frame is sent the write event
is called and the stream will be finally closed.
Some events like receiving a RST_STREAM can trigger the read handler of such
stream in closing state and cause unexpected processing that can result in
another attempt to finalize the request. To prevent it the read handler is
now set to ngx_http_empty_handler.
Thanks to Amazon.
There is no reason to add the "Content-Length: 0" header to a proxied request
without body if the header isn't presented in the original request.
Thanks to Amazon.
According to RFC 7540, an endpoint should not send more than one RST_STREAM
frame for any stream.
Also, now all the data frames will be skipped while termination.
The ngx_http_v2_finalize_connection() closes current stream, but that is an
invalid operation while processing unbuffered upload. This results in access
to already freed memory, since the upstream module sets a cleanup handler that
also finalizes the request.
A special last buffer with cl->buf->pos set to NULL can be present in
a chain when writing request body if chunked encoding was used. This
resulted in a NULL pointer dereference if it happened to be the only
buffer left after a do...while loop iteration in ngx_write_chain_to_file().
The problem originally appeared in nginx 1.3.9 with chunked encoding
support. Additionally, rev. 3832b608dc8d (nginx 1.9.13) changed the
minimum number of buffers to trigger this from IOV_MAX (typically 1024)
to NGX_IOVS_PREALLOCATE (typically 64).
Fix is to skip such buffers in ngx_chain_to_iovec(), much like it is
done in other places.
Previously, the stream's window was kept zero in order to prevent a client
from sending the request body before it was requested (see 887cca40ba6a for
details). Until such initial window was acknowledged all requests with
data were rejected (see 0aa07850922f for details).
That approach revealed a number of problems:
1. Some clients (notably MS IE/Edge, Safari, iOS applications) show an error
or even crash if a stream is rejected;
2. This requires at least one RTT for every request with body before the
client receives window update and able to send data.
To overcome these problems the new directive "http2_body_preread_size" is
introduced. It sets the initial window and configures a special per stream
preread buffer that is used to save all incoming data before the body is
requested and processed.
If the directive's value is lower than the default initial window (65535),
as previously, all streams with data will be rejected until the new window
is acknowledged. Otherwise, no special processing is used and all requests
with data are welcome right from the connection start.
The default value is chosen to be 64k, which is bigger than the default
initial window. Setting it to zero is fully complaint to the previous
behavior.
