This is a recommended behavior by RFC 7301 and is useful
for mitigation of protocol confusion attacks [1].
To avoid possible negative effects, list of supported protocols
was extended to include all possible HTTP protocol ALPN IDs
registered by IANA [2], i.e. "http/1.0" and "http/0.9".
[1] https://alpaca-attack.com/
[2] https://www.iana.org/assignments/tls-extensiontype-values/
In b87b7092cedb (nginx 1.21.1), logging level of "upstream sent invalid
header" errors was accidentally changed to "info". This change restores
the "error" level, which is a proper logging level for upstream-side
errors.
The u->keepalive flag is initialized early if the response has no body
(or an empty body), and needs to be reset if there are any extra data,
similarly to how it is done in ngx_http_proxy_copy_filter(). Missed
in 83c4622053b0.
The "proxy_half_close" directive enables handling of TCP half close. If
enabled, connection to proxied server is kept open until both read ends get
EOF. Write end shutdown is properly transmitted via proxy.
Do this only when the entire request body is empty and
r->request_body_in_file_only is set.
The issue manifested itself with missing warning "a client request body is
buffered to a temporary file" when the entire rb->buf is full and all buffers
are delayed by a filter.
The request body filter chain is no longer called after processing
a DATA frame. Instead, we now post a read event to do this. This
ensures that multiple small DATA frames read during the same event loop
iteration are coalesced together, resulting in much faster processing.
Since rb->buf can now contain unprocessed data, window update is no
longer sent in ngx_http_v2_state_read_data() in case of flow control
being used due to filter buffering. Instead, window will be updated
by ngx_http_v2_read_client_request_body_handler() in the posted read
event.
Following rb->filter_need_buffering changes, request body reading is
only finished after the filter chain is called and rb->last_saved is set.
As such, with r->request_body_no_buffering, timer on fc->read is no
longer removed when the last part of the body is received, potentially
resulting in incorrect behaviour.
The fix is to call ngx_http_v2_process_request_body() from the
ngx_http_v2_read_unbuffered_request_body() function instead of
directly calling ngx_http_v2_filter_request_body(), so the timer
is properly removed.
In the body read handler, the window was incorrectly calculated
based on the full buffer size instead of the amount of free space
in the buffer. If the request body is buffered by a filter, and
the buffer is not empty after the read event is generated by the
filter to resume request body processing, this could result in
"http2 negative window update" alerts.
Further, in the body ready handler and in ngx_http_v2_state_read_data()
the buffer wasn't cleared when the data were already written to disk,
so the client might stuck without window updates.
If a filter wants to buffer the request body during reading (for
example, to check an external scanner), it can now do so. To make
it possible, the code now checks rb->last_saved (introduced in the
previous change) along with rb->rest == 0.
Since in HTTP/2 this requires flow control to avoid overflowing the
request body buffer, so filters which need buffering have to set
the rb->filter_need_buffering flag on the first filter call. (Note
that each filter is expected to call the next filter, so all filters
will be able set the flag if needed.)
It indicates that the last buffer was received by the save filter,
and can be used to check this at higher levels. To be used in the
following changes.
If due to an error ngx_http_request_body_save_filter() is called
more than once with rb->rest == 0, this used to result in a segmentation
fault. Added an alert to catch such errors, just in case.
Previously, fully preread unbuffered requests larger than client body
buffer size were saved to disk, despite the fact that "unbuffered" is
expected to imply no disk buffering.
The save body filter saves the request body to disk once the buffer is full.
Yet in HTTP/2 this might happen even if there is no need to save anything
to disk, notably when content length is known and the END_STREAM flag is
sent in a separate empty DATA frame. Workaround is to provide additional
byte in the buffer, so saving the request body won't be triggered.
This fixes unexpected request body disk buffering in HTTP/2 observed after
the previous change when content length is known and the END_STREAM flag
is sent in a separate empty DATA frame.
In particular, now the code always uses a buffer limited by
client_body_buffer_size. At the cost of an additional copy it
ensures that small DATA frames are not directly mapped to small
write() syscalls, but rather buffered in memory before writing.
Further, requests without Content-Length are no longer forced
to use temporary files.
With SSL it is possible that an established connection is ready for
reading after the handshake. Further, events might be already disabled
in case of level-triggered event methods. If this happens and
ngx_http_upstream_send_request() blocks waiting for some data from
the upstream, such as flow control in case of gRPC, the connection
will time out due to no read events on the upstream connection.
Fix is to explicitly check the c->read->ready flag if sending request
blocks and post a read event if it is set.
Note that while it is possible to modify ngx_ssl_handshake() to keep
read events active, this won't completely resolve the issue, since
there can be data already received during the SSL handshake
(see 573bd30e46b4).
This adds new Auth-SSL-Protocol and Auth-SSL-Cipher headers to
the mail proxy auth protocol when SSL is enabled.
This can be useful for detecting users using older clients that
negotiate old ciphers when you want to upgrade to newer
TLS versions of remove suppport for old and insecure ciphers.
You can use your auth backend to notify these users before the
upgrade that they either need to upgrade their client software
or contact your support team to work out an upgrade path.
To load old/weak server or client certificates it might be needed to adjust
the security level, as introduced in OpenSSL 1.1.0. This change ensures that
ciphers are set before loading the certificates, so security level changes
via the cipher string apply to certificate loading.
Export ciphers are forbidden to negotiate in TLS 1.1 and later protocol modes.
They are disabled since OpenSSL 1.0.2g by default unless explicitly configured
with "enable-weak-ssl-ciphers", and completely removed in OpenSSL 1.1.0.
A new behaviour was introduced in OpenSSL 1.1.1e, when a peer does not send
close_notify before closing the connection. Previously, it was to return
SSL_ERROR_SYSCALL with errno 0, known since at least OpenSSL 0.9.7, and is
handled gracefully in nginx. Now it returns SSL_ERROR_SSL with a distinct
reason SSL_R_UNEXPECTED_EOF_WHILE_READING ("unexpected eof while reading").
This leads to critical errors seen in nginx within various routines such as
SSL_do_handshake(), SSL_read(), SSL_shutdown(). The behaviour was restored
in OpenSSL 1.1.1f, but presents in OpenSSL 3.0 by default.
Use of the SSL_OP_IGNORE_UNEXPECTED_EOF option added in OpenSSL 3.0 allows
to set a compatible behaviour to return SSL_ERROR_ZERO_RETURN:
https://git.openssl.org/?p=openssl.git;a=commitdiff;h=09b90e0
See for additional details: https://github.com/openssl/openssl/issues/11381
The OPENSSL_SUPPRESS_DEPRECATED macro is used to suppress deprecation warnings.
This covers Session Tickets keys, SSL Engine, DH low level API for DHE ciphers.
Unlike OPENSSL_API_COMPAT, it works well with OpenSSL built with no-deprecated.
In particular, it doesn't unhide various macros in OpenSSL includes, which are
meant to be hidden under OPENSSL_NO_DEPRECATED.
The only consumer is a callback function for SSL_CTX_set_tmp_rsa_callback()
deprecated in OpenSSL 1.1.0. Now the function is conditionally compiled too.
The latest HTTP/1.1 draft describes Transfer-Encoding in HTTP/1.0 as having
potentially faulty message framing as that could have been forwarded without
handling of the chunked encoding, and forbids processing subsequest requests
over that connection: https://github.com/httpwg/http-core/issues/879.
While handling of such requests is permitted, the most secure approach seems
to reject them.
The c->read->ready and c->write->ready flags might be reset during
the handshake, and not set again if the handshake was finished on
the other event. At the same time, some data might be read from
the socket during the handshake, so missing c->read->ready flag might
result in a connection hang, for example, when waiting for an SMTP
greeting (which was already received during the handshake).
Found by Sergey Kandaurov.
