Not only this is consistent with a case without SNI, but this also
prevents abusing configurations that assume that the $host variable
is limited to one of the configured names for a server.
An example of potentially unsafe configuration:
server {
listen 443 ssl default_server;
...
}
server {
listen 443;
server_name example.com;
location / {
proxy_pass http://$host;
}
}
Note: it is possible to negotiate "example.com" by SNI, and to request
arbitrary host name that does not exist in the configuration above.
Previously, this was done only after the whole request header
was parsed, and if an error occurred earlier then the request
was processed in the default server (or server chosen by SNI),
while r->headers_in.server might be set to the value from the
Host: header or host from request line.
r->headers_in.server is in turn used for $host variable and
in HTTP redirects if "server_name_in_redirect" is disabled.
Without the change, configurations that rely on this during
error handling are potentially unsafe if SNI is used.
This change also allows to use server specific settings of
"underscores_in_headers", "ignore_invalid_headers", and
"large_client_header_buffers" directives for HTTP requests
and HTTPS requests without SNI.
The request object will not be created until SSL handshake is complete.
This simplifies adding another connection handler that does not need
request object right after handshake (e.g., SPDY).
There are also a few more intentional effects:
- the "client_header_buffer_size" directive will be taken from the
server configuration that was negotiated by SNI;
- SSL handshake errors and timeouts are not logged into access log
as bad requests;
- ngx_ssl_create_connection() is not called until the first byte of
ClientHello message was received. This also decreases memory
consumption if plain HTTP request is sent to SSL socket.
Previously, only the first request in a connection was assigned the
configuration selected by SNI. All subsequent requests initially
used the default server's configuration, ignoring SNI, which was
wrong.
Now all subsequent requests in a connection will initially use the
configuration selected by SNI. This is done by storing a pointer
to configuration in http connection object. It points to default
server's configuration initially, but changed upon receipt of SNI.
(The request's configuration can be further refined when parsing
the request line and Host: header.)
This change was not made specific to SNI as it also allows slightly
faster access to configuration without the request object.
This change helps to decouple ngx_http_ssl_servername() from the request
object.
Note: now we close connection in case of error during server name lookup
for request. Previously, we did so only for HTTP/0.9 requests.
In case of error in the read event handling we close a connection
by calling ngx_http_close_connection(), that also destroys connection
pool. Thereafter, an attempt to free a buffer (added in r4892) that
was allocated from the pool could cause SIGSEGV and is meaningless
as well (the buffer already freed with the pool).
This allows to proxy WebSockets by using configuration like this:
location /chat/ {
proxy_pass http://backend;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
Connection upgrade is allowed as long as it was requested by a client
via the Upgrade request header.
idle connections.
This behaviour is consistent with the ngx_http_set_keepalive() function and it
should decrease memory usage in some cases (especially if epoll/rtsig is used).
This parameter allows to don't require certificate to be signed by
a trusted CA, e.g. if CA certificate isn't known in advance, like in
WebID protocol.
Note that it doesn't add any security unless the certificate is actually
checked to be trusted by some external means (e.g. by a backend).
Patch by Mike Kazantsev, Eric O'Connor.
This includes handling of ETag headers (if present in a response) with
basic support for If-Match, If-None-Match conditionals in not modified
filter.
Note that the "r->headers_out.last_modified_time == -1" check in the not
modified filter is left as is intentionally. It's to prevent handling
of If-* headers in case of proxy without cache (much like currently
done with If-Modified-Since).
There are too many problems with special NTFS streams, notably "::$data",
"::$index_allocation" and ":$i30:$index_allocation".
For now we don't reject all URIs with ":" like Apache does as there are no
good reasons seen yet, and there are multiple programs using it in URLs
(e.g. MediaWiki).
Example configuration to reproduce:
location /image/ {
error_page 415 = /zero;
image_filter crop 100 100;
proxy_pass http://127.0.0.1:8080;
proxy_store on;
}
location /zero {
return 204;
}
The problem appeared if upstream returned (big enough) non-image file,
causing 415 to be generated by image filter.
With r->filter_finalize set the ngx_http_finalize_connection() wasn't
called from ngx_http_finalize_request() called with NGX_OK, resulting in
r->main->count not being decremented, thus causing request hang in some
rare situations.
See here for more details:
http://mailman.nginx.org/pipermail/nginx-devel/2012-May/002190.html
Patch by Yichun Zhang (agentzh).
Now redirects to named locations are counted against normal uri changes
limit, and post_action respects this limit as well. As a result at least
the following (bad) configurations no longer trigger infinite cycles:
1. Post action which recursively triggers post action:
location / {
post_action /index.html;
}
2. Post action pointing to nonexistent named location:
location / {
post_action @nonexistent;
}
3. Recursive error page for 500 (Internal Server Error) pointing to
a nonexistent named location:
location / {
recursive_error_pages on;
error_page 500 @nonexistent;
return 500;
}
Without the protection, subrequest loop results in r->count overflow and
SIGSEGV. Protection was broken in 0.7.25.
Note that this also limits number of parallel subrequests. This
wasn't exactly the case before 0.7.25 as local subrequests were
completed directly.
See here for details:
http://nginx.org/pipermail/nginx-ru/2010-February/032184.html
Additional parsing logic added to correctly handle RFC 3986 compliant IPv6 and
IPvFuture characters enclosed in square brackets.
The host validation was completely rewritten. The behavior for non IP literals
was changed in a more proper and safer way:
- Host part is now delimited either by the first colon or by the end of string
if there's no colon. Previously the last colon was used as delimiter which
allowed substitution of a port number in the $host variable.
(e.g. Host: 127.0.0.1:9000:80)
- Fixed stripping of the ending dot in the Host header when the host was also
followed by a port number.
(e.g. Host: nginx.com.:80)
- Fixed upper case characters detection. Previously it was broken which led to
wasting memory and CPU.
Second aio post happened when timer set by limit_rate expired while we have
aio request in flight, resulting in "second aio post" alert and socket leak.
The patch adds actual protection from aio calls with r->aio already set to
aio sendfile code in ngx_http_copy_filter(). This should fix other cases
as well, e.g. when sending buffered to disk upstream replies while still
talking to upstream.
The ngx_http_writer() is also fixed to handle the above case (though it's
mostly optimization now).
Reported by Oleksandr V. Typlyns'kyi.
SSL_set_SSL_CTX() doesn't touch values cached within ssl connection
structure, it only changes certificates (at least as of now, OpenSSL
1.0.0d and earlier).
As a result settings like ssl_verify_client, ssl_verify_depth,
ssl_prefer_server_ciphers are only configurable on per-socket basis while
with SNI it should be possible to specify them different for two servers
listening on the same socket.
Workaround is to explicitly re-apply settings we care about from context
to ssl connection in servername callback.
Note that SSL_clear_options() is only available in OpenSSL 0.9.8m+. I.e.
with older versions it is not possible to clear ssl_prefer_server_ciphers
option if it's set in default server for a socket.
runs ngx_http_core_run_phases(), and starts a request processing again.
The write event has clear type and remained in a keepalive connection.
The bug was introduced in r3050.
