Previously, "%uA" was used, which corresponds to ngx_atomic_uint_t.
Size of ngx_atomic_uint_t can be easily different from uint64_t,
leading to undefined results.
In TLSv1.3, NewSessionTicket messages arrive after the handshake and
can come at any time. Therefore we use a callback to save the session
when we know about it. This approach works for < TLSv1.3 as well.
The callback function is set once per location on merge phase.
Since SSL_get_session() in BoringSSL returns an unresumable session for
TLSv1.3, peer save_session() methods have been updated as well to use a
session supplied within the callback. To preserve API, the session is
cached in c->ssl->session. It is preferably accessed in save_session()
methods by ngx_ssl_get_session() and ngx_ssl_get0_session() wrappers.
In OpenSSL 1.1.0 the SSL_CTRL_CLEAR_OPTIONS macro was removed, so
conditional compilation test on it results in SSL_clear_options()
and SSL_CTX_clear_options() not being used. Notably, this caused
"ssl_prefer_server_ciphers off" to not work in SNI-based virtual
servers if server preference was switched on in the default server.
It looks like the only possible fix is to test OPENSSL_VERSION_NUMBER
explicitly.
Starting with OpenSSL 1.1.0, SSL_R_UNSUPPORTED_PROTOCOL instead of
SSL_R_UNKNOWN_PROTOCOL is reported when a protocol is disabled via
an SSL_OP_NO_* option.
Additionally, SSL_R_VERSION_TOO_LOW is reported when using MinProtocol
or when seclevel checks (as set by @SECLEVEL=n in the cipher string)
rejects a protocol, and this is what happens with SSLv3 and @SECLEVEL=1,
which is the default.
There is also the SSL_R_VERSION_TOO_HIGH error code, but it looks like
it is not possible to trigger it.
There should be at least one worker connection for each listening socket,
plus an additional connection for channel between worker and master,
or starting worker processes will fail.
Previously, listenings sockets were not cloned if the worker_processes
directive was specified after "listen ... reuseport".
This also simplifies upcoming configuration check on the number
of worker connections, as it needs to know the number of listening
sockets before cloning.
The variable keeps the latest SSL protocol version supported by the client.
The variable has the same format as $ssl_protocol.
The version is read from the client_version field of ClientHello. If the
supported_versions extension is present in the ClientHello, then the version
is set to TLSv1.3.
Errors when sending UDP datagrams can happen, e.g., when local IP address
changes (see fa0e093b64d7), or an unavailable DNS server on the LAN can cause
send() to fail with EHOSTDOWN on BSD systems. If this happens during
initial query, retry sending immediately, to a different DNS server when
possible. If this is not enough, allow normal resend to happen by ignoring
the return code of the second ngx_resolver_send_query() call, much like we
do in ngx_resolver_resend().
The "http request" and "https proxy request" errors cannot happen
with HTTP due to pre-handshake checks in ngx_http_ssl_handshake(),
but can happen when SSL is used in stream and mail modules.
With gRPC it is possible that a request sending is blocked due to flow
control. Moreover, further sending might be only allowed once the
backend sees all the data we've already sent. With such a backend
it is required to clear the TCP_NOPUSH socket option to make sure all
the data we've sent are actually delivered to the backend.
As such, we now clear TCP_NOPUSH in ngx_http_upstream_send_request()
also on NGX_AGAIN if c->write->ready is set. This fixes a test (which
waits for all the 64k bytes as per initial window before allowing more
bytes) with sendfile enabled when the body was written to a file
in a different context.
Now tcp_nopush on peer connections is disabled if it is disabled on
the client connection, similar to how we handle c->sendfile. Previously,
tcp_nopush was always used on upstream connections, regardless of
the "tcp_nopush" directive.
We copy input buffers to our buffers, so various flags might be
unexpectedly set in buffers returned by ngx_chain_get_free_buf().
In particular, the b->in_file flag might be set when the body was
written to a file in a different context. With sendfile enabled this
in turn might result in protocol corruption if such a buffer was reused
for a control frame.
Make sure to clear buffers and set only fields we really need to be set.
The module implements random load-balancing algorithm with optional second
choice. In the latter case, the best of two servers is chosen, accounting
number of connections and server weight.
Example:
upstream u {
random [two [least_conn]];
server 127.0.0.1:8080;
server 127.0.0.1:8081;
server 127.0.0.1:8082;
server 127.0.0.1:8083;
}
Before 4a8c9139e579, ngx_resolver_create() didn't use configuration
pool, and allocations were done using malloc().
In 016352c19049, when resolver gained support of several servers,
new allocations were done from the pool.
With u->conf->preserve_output set the request body file might be used
after the response header is sent, so avoid cleaning it. (Normally
this is not a problem as u->conf->preserve_output is only set with
r->request_body_no_buffering, but the request body might be already
written to a file in a different context.)
Previously, only one client packet could be processed in a udp stream session
even though multiple response packets were supported. Now multiple packets
coming from the same client address and port are delivered to the same stream
session.
If it's required to maintain a single stream of data, nginx should be
configured in a way that all packets from a client are delivered to the same
worker. On Linux and DragonFly BSD the "reuseport" parameter should be
specified for this. Other systems do not currently provide appropriate
mechanisms. For these systems a single stream of udp packets is only
guaranteed in single-worker configurations.
The proxy_response directive now specifies how many packets are expected in
response to a single client packet.
Previously, ngx_event_recvmsg() got remote socket addresses after creating
the connection object. In preparation to handling multiple UDP packets in a
single session, this code was moved up.
On Linux recvmsg() syscall may return a zero-length client address when
receiving a datagram from an unbound unix datagram socket. It is usually
assumed that socket address has at least the sa_family member. Zero-length
socket address caused buffer over-read in functions which receive socket
address, for example ngx_sock_ntop(). Typically the over-read resulted in
unexpected socket family followed by session close. Now a fake socket address
is allocated instead of a zero-length client address.
Negative times can appear since workers only update time on an event
loop iteration start. If a worker was blocked for a long time during
an event loop iteration, it is possible that another worker already
updated the time stored in the node. As such, time since last update
of the node (ms) will be negative.
Previous code used ngx_abs(ms) in the calculations. That is, negative
times were effectively treated as positive ones. As a result, it was
not possible to maintain high request rates, where the same node can be
updated multiple times from during an event loop iteration.
In particular, this affected setups with many SSL handshakes, see
http://mailman.nginx.org/pipermail/nginx/2018-May/056291.html.
Fix is to only update the last update time stored in the node if the
new time is larger than previously stored one. If a future time is
stored in the node, we preserve this time as is.
To prevent breaking things on platforms without monotonic time available
if system time is updated backwards, a safety limit of 60 seconds is
used. If the time stored in the node is more than 60 seconds in the future,
we assume that the time was changed backwards and update lr->last
to the current time.
The bug in question was fixed in glibc 2.3.2 and is no longer expected
to manifest itself on real servers. On the other hand, the workaround
causes compilation problems on various systems. Previously, we've
already fixed the code to compile with musl libc (fd6fd02f6a4d), and
now it is broken on Fedora 28 where glibc's crypt library was replaced
by libxcrypt. So the workaround was removed.
