Now the session object is assigned to c->data while ngx_http_connection_t
object is referenced by its http_connection field, similar to
ngx_http_v2_connection_t and ngx_http_request_t.
The change allows to eliminate v3_session field from ngx_http_connection_t.
The field was under NGX_HTTP_V3 macro, which was a source of binary
compatibility problems when nginx/module is build with/without HTTP/3 support.
Postponing is essential since c->data should retain the reference to
ngx_http_connection_t object throughout QUIC handshake, because SSL callbacks
ngx_http_ssl_servername() and ngx_http_ssl_alpn_select() rely on this.
Instead, when worker is shutting down and handshake is not yet completed,
connection is terminated immediately.
Previously the callback could be called while QUIC handshake was in progress
and, what's more important, before the init() callback. Now it's postponed
after init().
This change is a preparation to postponing HTTP/3 session creation to init().
Previously QUIC did not have such parameter and handshake duration was
controlled by HTTP/3. However that required creating and storing HTTP/3
session on first client datagram. Apparently there's no convenient way to
store the session object until QUIC handshake is complete. In the followup
patches session creation will be postponed to init() callback.
As explained in BoringSSL change[1], levels were introduced in the original
QUIC API to draw a line between when keys are released and when are active.
In the new QUIC API they are released in separate calls when it's needed.
BoringSSL has then a consideration to remove levels API, hence the change.
If not available e.g. from a QUIC packet header, levels can be taken based on
keys availability. The only real use of levels is to prevent using app keys
before they are active in QuicTLS that provides the old BoringSSL QUIC API,
it is replaced with an equivalent check of c->ssl->handshaked.
This change also removes OpenSSL compat shims since they are no longer used.
The only exception left is caching write level from the keylog callback in
the internal field which is a handy equivalent of checking keys availability.
[1] https://boringssl.googlesource.com/boringssl/+/1e859054
As per RFC 9000, section 10.2.3, to ensure that peer successfully removed
packet protection, CONNECTION_CLOSE can be sent in multiple packets using
different packet protection levels.
Now it is sent in all protection levels available.
This roughly corresponds to the following paragraph:
* Prior to confirming the handshake, a peer might be unable to process 1-RTT
packets, so an endpoint SHOULD send a CONNECTION_CLOSE frame in both Handshake
and 1-RTT packets. A server SHOULD also send a CONNECTION_CLOSE frame in an
Initial packet.
In practice, this change allows to avoid sending an Initial packet when we know
the client has handshake keys, by checking if we have discarded initial keys.
Also, this fixes sending CONNECTION_CLOSE when using QuicTLS with old QUIC API,
where TLS stack releases application read keys before handshake confirmation;
it is fixed by sending CONNECTION_CLOSE additionally in a Handshake packet.
Status header with an empty reason-phrase, such as "Status: 404 ", is
valid per CGI specification, but looses the trailing space during parsing.
Currently, this results in "HTTP/1.1 404" HTTP status line in the response,
which violates HTTP specification due to missing trailing space.
With this change, only the status code is used from such short Status
header lines, so nginx will generate status line itself, with the space
and appropriate reason phrase if available.
Reported at:
https://mailman.nginx.org/pipermail/nginx/2023-August/EX7G4JUUHJWJE5UOAZMO5UD6OJILCYGX.html
Previously, a socket error on a path being validated resulted in validation
error and subsequent QUIC connection closure. Now the error is ignored and
path validation proceeds as usual, with several retries and a timeout.
When validating the old path after an apparent migration, that path may already
be unavailable and sendmsg() may return an error, which should not result in
QUIC connection close.
When validating the new path, it's possible that the new client address is
spoofed (See RFC 9000, 9.3.2. On-Path Address Spoofing). This address may
as well be unavailable and should not trigger QUIC connection closure.
Previously, original dcid was used to receive initial client packets in case
server initial response was lost. However, last dcid should be used instead.
These two are the same unless retry is used. In case of retry, client resends
initial packet with a new dcid, that is different from the original dcid. If
server response is lost, the client resends this packet again with the same
dcid. This is shown in RFC 9000, 7.3. Authenticating Connection IDs, Figure 8.
The issue manifested itself with creating multiple server sessions in response
to each post-retry client initial packet, if server response is lost.
Since at least f9fbeb4ee0de and certainly after 924882f42dea, which
TLS Key Update support predates, queued data output is deferred to a
posted push handler. To address timing signals after these changes,
generating next keys is now posted to run after the push handler.
Previously, NGX_AGAIN returned by ngx_quic_send() was treated by
ngx_quic_frame_sendto() as error, which triggered errors in its callers.
However, a blocked socket is not an error. Now NGX_AGAIN is passed as is to
the ngx_quic_frame_sendto() callers, which can safely ignore it.
When probe timeout expired while congestion window was exhausted, probe PINGs
could not be sent. As a result, lost packets could not be declared lost and
congestion window could not be freed for new packets. This deadlock
continued until connection idle timeout expiration.
Now PINGs are sent separately from the frame queue without congestion control,
as specified by RFC 9002, Section 7:
An endpoint MUST NOT send a packet if it would cause bytes_in_flight
(see Appendix B.2) to be larger than the congestion window, unless the
packet is sent on a PTO timer expiration (see Section 6.2) or when entering
recovery (see Section 7.3.2).
Previously, PTO handler analyzed the first packet in the sent queue for the
timeout expiration. However, the last sent packet should be analyzed instead.
An example is timeout calculation in ngx_quic_set_lost_timer().
Previously the field pnum of a potentially freed frame was accessed. Now the
value is copied to a local variable. The old behavior did not cause any
problems since the frame memory is not freed, but is moved to a free queue
instead.
In non-GSO mode, a datagram is sent if congestion window is not exceeded by the
time of send. The window could be exceeded by a small amount after the send.
In GSO mode, congestion window was checked in a similar way, but for all
concatenated datagrams as a whole. This could result in exceeding congestion
window by a lot. Now congestion window is checked for every datagram in GSO
mode as well.
Previously it was added to the tail as all other frames. However, if the
amount of queued data is large, it could delay the delivery of ACK, which
could trigger frames retransmissions and slow down the connection.
Previously ACK was not generated if max_ack_delay was not yet expired and the
number of unacknowledged ack-eliciting packets was less than two, as allowed by
RFC 9000 13.2.1-13.2.2. However this only makes sense to avoid sending ACK-only
packets, as explained by the RFC:
On the other hand, reducing the frequency of packets that carry only
acknowledgments reduces packet transmission and processing cost at both
endpoints.
Now ACK is delayed only if output frame queue is empty. Otherwise ACK is sent
immediately, which significantly improves QUIC performance with certain tests.
With this change, the NGX_OPENSSL_NO_CONFIG macro is defined when nginx
is asked to build OpenSSL itself. And with this macro automatic loading
of OpenSSL configuration (from the build directory) is prevented unless
the OPENSSL_CONF environment variable is explicitly set.
Note that not loading configuration is broken in OpenSSL 1.1.1 and 1.1.1a
(fixed in OpenSSL 1.1.1b, see https://github.com/openssl/openssl/issues/7350).
If nginx is used to compile these OpenSSL versions, configuring nginx with
NGX_OPENSSL_NO_CONFIG explicitly set to 0 might be used as a workaround.
Following OpenSSL 0.9.8f, OpenSSL tries to load application-specific
configuration section first, and then falls back to the "openssl_conf"
default section if application-specific section is not found, by using
CONF_modules_load_file(CONF_MFLAGS_DEFAULT_SECTION). Therefore this
change is not expected to introduce any compatibility issues with existing
configurations. It does, however, make it easier to configure specific
OpenSSL settings for nginx in system-wide OpenSSL configuration
(ticket #2449).
Instead of checking OPENSSL_VERSION_NUMBER when using the OPENSSL_init_ssl()
interface, the code now tests for OPENSSL_INIT_LOAD_CONFIG to be defined and
true, and also explicitly excludes LibreSSL. This ensures that this interface
is not used with BoringSSL and LibreSSL, which do not provide additional
library initialization settings, notably the OPENSSL_INIT_set_config_appname()
call.
Similarly to 6822:c045b4926b2c, environment variables introduced with
the "env" directive (and "NGINX_BPF_MAPS" added by QUIC) are now allocated
via ngx_alloc(), and explicitly freed by a cleanup handler if no longer used.
In collaboration with Sergey Kandaurov.
Previously used constant EVP_GCM_TLS_TAG_LEN had misleading name since it was
used not only with GCM, but also with CHACHAPOLY. Now a new constant
NGX_QUIC_TAG_LEN introduced. Luckily all AEAD algorithms used by QUIC have
the same tag length of 16.
Previously, computing rttvar used an updated smoothed_rtt value as per
RFC 9002, section 5.3, which appears to be specified in a wrong order.
A technical errata ID 7539 is reported.
Although it has better implementation status than HTTP/3 server push,
it remains of limited use, with adoption numbers seen as negligible.
Per IETF 102 materials, server push was used only in 0.04% of sessions.
It was considered to be "difficult to use effectively" in RFC 9113.
Its use is further limited by badly matching to fetch/cache/connection
models in browsers, see related discussions linked from [1].
Server push was disabled in Chrome 106 [2].
The http2_push, http2_push_preload, and http2_max_concurrent_pushes
directives are made obsolete. In particular, this essentially reverts
7201:641306096f5b and 7207:3d2b0b02bd3d.
[1] https://jakearchibald.com/2017/h2-push-tougher-than-i-thought/
[2] https://chromestatus.com/feature/6302414934114304
It has been deprecated since 7270:46c0c7ef4913 (1.15.0) in favour of
the "ssl" parameter of the "listen" directive, which has been available
since 2224:109849282793 (0.7.14).
The directive enables HTTP/2 in the current server. The previous way to
enable HTTP/2 via "listen ... http2" is now deprecated. The new approach
allows to share HTTP/2 and HTTP/0.9-1.1 on the same port.
For SSL connections, HTTP/2 is now selected by ALPN callback based on whether
the protocol is enabled in the virtual server chosen by SNI. This however only
works since OpenSSL 1.0.2h, where ALPN callback is invoked after SNI callback.
For older versions of OpenSSL, HTTP/2 is enabled based on the default virtual
server configuration.
For plain TCP connections, HTTP/2 is now auto-detected by HTTP/2 preface, if
HTTP/2 is enabled in the default virtual server. If preface is not matched,
HTTP/0.9-1.1 is assumed.
Previously, rec.level field was not uninitialized in SSL_provide_quic_data().
As a result, its value was always ssl_encryption_initial. Later in
ngx_quic_ciphers() such level resulted in resetting the cipher to
TLS1_3_CK_AES_128_GCM_SHA256 and using AES128 to encrypt the packet.
Now the level is initialized and the right cipher is used.
The layer is enabled as a fallback if the QUIC support is configured and the
BoringSSL API wasn't detected, or when using the --with-openssl option, also
compatible with QuicTLS and LibreSSL. For the latter, the layer is assumed
to be present if QUIC was requested, so it needs to be undefined to prevent
QUIC API redefinition as appropriate.
A previously used approach to test the TLSEXT_TYPE_quic_transport_parameters
macro doesn't work with OpenSSL 3.2 master branch where this macro appeared
with incompatible QUIC API. To fix the build there, the test is revised to
pass only for QuicTLS and LibreSSL.
Previously, ngx_quic_close_connection() could be called in a way that QUIC
connection was accessed after the call. In most cases the connection is not
closed right away, but close timeout is scheduled. However, it's not always
the case. Also, if the close process started earlier for a different reason,
calling ngx_quic_close_connection() may actually close the connection. The
connection object should not be accessed after that.
Now, when possible, return statement is added to eliminate post-close connection
object access. In other places ngx_quic_close_connection() is substituted with
posting close event.
Also, the new way of closing connection in ngx_quic_stream_cleanup_handler()
fixes another problem in this function. Previously it passed stream connection
instead of QUIC connection to ngx_quic_close_connection(). This could result
in incomplete connection shutdown. One consequence of that could be that QUIC
streams were freed without shutting down their application contexts. This could
result in another use-after-free.
Found by Coverity (CID 1530402).
The qsock->sockaddr field is a ngx_sockaddr_t union, and therefore can hold
any sockaddr (and union members, such qsock->sockaddr.sockaddr, can be used
to access appropriate variant of the sockaddr). It is better to set it via
qsock->sockaddr itself though, and not qsock->sockaddr.sockaddr, so static
analyzers won't complain about out-of-bounds access.
Prodded by Coverity (CID 1530403).
