GetQueuedCompletionStatus() document on MSDN says the
following signature:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa364986.aspx
BOOL WINAPI GetQueuedCompletionStatus(
_In_ HANDLE CompletionPort,
_Out_ LPDWORD lpNumberOfBytes,
_Out_ PULONG_PTR lpCompletionKey,
_Out_ LPOVERLAPPED *lpOverlapped,
_In_ DWORD dwMilliseconds
);
In the latest specification, the type of the third argument
(lpCompletionKey) is PULONG_PTR not LPDWORD.
Due to the u->headers_in.last_modified_time not being correctly initialized,
this variable was evaluated to "Thu, 01 Jan 1970 00:00:00 GMT" for responses
cached without the "Last-Modified" header which resulted in subsequent proxy
requests being sent with "If-Modified-Since: Thu, 01 Jan 1970 00:00:00 GMT"
header.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Previously, a value of the "send" variable wasn't properly adjusted
in a rare case when syscall was interrupted by a signal. As a result,
these functions could send less data than the limit allows.
The c->sent is reset to 0 on each request by server-side http code,
so do the same on client side. This allows to count number of bytes
sent in a particular request.
One intentional side effect of this change is that key is allowed only
in the first position. Previously, it was possible to specify the key
variable at any position, but that was never documented, and is contrary
with nginx configuration practice for positional parameters.
One intentional side effect of this change is that key is allowed only
in the first position. Previously, it was possible to specify the key
variable at any position, but that was never documented, and is contrary
to nginx configuration practice for positional parameters.
If a syslog daemon is restarted and the unix socket is used, further logging
might stop to work. In case of send error, socket is closed, forcing
a reconnection at the next logging attempt.
The ngx_cycle->log is used when sending the message. This allows to log syslog
send errors in another log.
Logging to syslog after its cleanup handler has been executed was prohibited.
Previously, this was possible from ngx_destroy_pool(), which resulted in error
messages caused by attempts to write into the closed socket.
The "processing" flag is renamed to "busy" to better match its semantics.
Previously, a file buffer start position was reset to the file start.
Now it's reset to the previous file buffer end. This fixes
reinitialization of requests having multiple successive parts of a
single file. Such requests are generated by fastcgi module.
This prevents inappropriate session reuse in unrelated server{}
blocks, while preserving ability to restore sessions on other servers
when using TLS Session Tickets.
Additionally, session context is now set even if there is no session cache
configured. This is needed as it's also used for TLS Session Tickets.
Thanks to Antoine Delignat-Lavaud and Piotr Sikora.
The new directives {proxy,fastcgi,scgi,uwsgi,memcached}_next_upstream_tries
and {proxy,fastcgi,scgi,uwsgi,memcached}_next_upstream_timeout limit
the number of upstreams tried and the maximum time spent for these tries
when searching for a valid upstream.
When memory allocation failed in ngx_http_upstream_cache(), the connection
would be terminated directly in ngx_http_upstream_init_request().
Return a INTERNAL_SERVER_ERROR response instead.
The ngx_init_setproctitle() function, as used on systems without
setproctitle(3), may fail due to memory allocation errors, and
therefore its return code needs to be checked.
Reported by Markus Linnala.
The etag->hash must be set to 0 to avoid an empty ETag header being
returned with the 500 Internal Server Error page after the memory
allocation failure.
Reported by Markus Linnala.
Some of the OpenSSL forks (read: BoringSSL) started removing unused,
no longer necessary and/or not really working bug workarounds along
with the SSL options and defines for them.
Instead of fixing nginx build after each removal, be proactive
and guard use of all SSL options for bug workarounds.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The messages "ngx_slab_alloc() failed: no memory in cache keys zone"
from the file cache slab allocator are suppressed since the allocation
is likely to succeed after the forced expiration of cache nodes.
The second allocation failure is reported.
In theory, this can provide a bit better distribution of latencies.
Also it simplifies the code, since ngx_queue_t is now used instead
of custom implementation.
Previously, a configuration like
location / {
ssi on;
ssi_types *;
set $http_foo "bar";
return 200 '<!--#echo var="http_foo" -->\n';
}
resulted in NULL pointer dereference in ngx_http_get_variable() as
the variable was explicitly added to the variables hash, but its
get_handler wasn't properly set in the hash. Fix is to make sure
that get_handler is properly set by ngx_http_variables_init_vars().
The SPDY module doesn't expect timers can be set on stream events for reasons
other than delaying output. But ngx_http_writer() could add timer on write
event if the delayed flag wasn't set and nginx is waiting for AIO completion.
That could cause delays in sending response over SPDY when file AIO was used.
perl_parse() function expects argv/argc-style argument list,
which according to the C standard must be NULL-terminated,
that is: argv[argc] == NULL.
This change fixes a crash (SIGSEGV) that could happen because
of the buffer overrun during perl module initialization.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
LibreSSL developers decided that LibreSSL is OpenSSL-2.0.0, so tests
for OpenSSL-1.0.2+ are now passing, even though the library doesn't
provide functions that are expected from that version of OpenSSL.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
This change adds support for using BoringSSL as a drop-in replacement
for OpenSSL without adding support for any of the BoringSSL-specific
features.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
This is really just a prerequisite for building against BoringSSL,
which doesn't provide either of those features.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Timeout may not be set on an upstream connection when we call
ngx_ssl_handshake() in ngx_http_upstream_ssl_init_connection(),
so make sure to arm it if it's not set.
Based on a patch by Yichun Zhang.
The ngx_http_geoip_city_float_variable and
ngx_http_geoip_city_int_variable functions did not always initialize
all variable fields like "not_found", which could lead to empty values
for those corresponding nginx variables randomly.
RFC3986 says that, for consistency, URI producers and normalizers
should use uppercase hexadecimal digits for all percent-encodings.
This is also what modern web browsers and other tools use.
Using lowercase hexadecimal digits makes it harder to interact with
those tools in case when use of the percent-encoded URI is required,
for example when $request_uri is part of the cache key.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Previously, ngx_http_map_uri_to_path() errors were not checked in
ngx_http_upstream_store(). Moreover, in case of errors temporary
files were not deleted, as u->store was set to 0, preventing cleanup
code in ngx_http_upstream_finalize_request() from removing them. With
this patch, u->store is set to 0 only if there were no errors.
Reported by Feng Gu.
This ensures that debug logging and the $uri variable (if used in
400 Bad Request processing) will not try to access uninitialized
memory.
Found by Sergey Bobrov.
Split SPDY header with multiple, NULL-separated values:
cookie: foo\0bar
into two separate HTTP headers with the same name:
cookie: foo
cookie: bar
Even though the logic for this behavior already existed
in the source code, it doesn't look that it ever worked
and SPDY streams with such headers were simply rejected.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
SSL_SESSION struct is internal part of the OpenSSL library and it's fields
should be accessed via API (when exposed), not directly.
The unfortunate side-effect of this change is that we're losing reference
count that used to be printed at the debug log level, but this seems to be
an acceptable trade-off.
Almost fixes build with -DOPENSSL_NO_SSL_INTERN.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The RSA_generate_key() is marked as deprecated and causes build to
fail. On the other hand, replacement function, RSA_generate_key_ex(),
requires much more code. Since RSA_generate_key() is only needed
for barely usable EXP ciphers, the #ifdef was added instead.
Prodded by Piotr Sikora.
This change is mostly cosmetic, because in practice this callback
is used only for 512-bit RSA keys.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Previously, <bn.h>, <dh.h>, <rand.h> and <rsa.h> were pulled in
by <engine.h> using OpenSSL's deprecated interface, which meant
that nginx couldn't have been built with -DOPENSSL_NO_DEPRECATED.
Both <x509.h> and <x509v3.h> are pulled in by <ocsp.h>, but we're
calling X509 functions directly, so let's include those as well.
<crypto.h> is pulled in by virtually everything, but we're calling
CRYPTO_add() directly, so let's include it as well.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The ngx_open_dir() function changed to restore name passed to it. This
fixes removing destination directory in dav module, as caught by dav.t.
The ngx_close_dir() function introduced to properly convert errors, as
FindClose() returns 0 on error.
Previously, the NGX_LOG_INFO level was used unconditionally. This is
correct for client SSL connections, but too low for connections to
upstream servers. To resolve this, ngx_connection_error() now used
to log this error, it will select logging level appropriately.
With this change, if an upstream connection is closed during SSL
handshake, it is now properly logged at "error" level.
Previously, nginx closed client connection in cases when a response body
from upstream was needed to be cached or stored but shouldn't be sent to
the client. While this is normal for HTTP, it is unacceptable for SPDY.
Fix is to use instead the p->downstream_error flag to prevent nginx from
sending anything downstream. To make this work, the event pipe code was
modified to properly cache empty responses with the flag set.
The ngx_http_upstream_dummy_handler() must be set regardless of
the read event state. This prevents possible additional call of
ngx_http_upstream_send_request_handler().
The check became meaningless after refactoring in 2a92804f4109.
With the loop currently in place, "current" can't be NULL, hence
the check can be dropped.
Additionally, the local variable "current" was removed to
simplify code, and pool->current now used directly instead.
Found by Coverity (CID 714236).
This isn't really important as configuration testing shortly ends with
a process termination which will free all sockets, though Coverity
complains.
Prodded by Coverity (CID 400872).
Previously, last_modified_time was tested against -1 to check if the
not modified filter should be skipped. Notably, this prevented nginx
from additional If-Modified-Since (et al.) checks on proxied responses.
Such behaviour is suboptimal in some cases though, as checks are always
skipped on responses from a cache with ETag only (without Last-Modified),
resulting in If-None-Match being ignored in such cases. Additionally,
it was not possible to return 412 from the If-Unmodified-Since if last
modification time was not known for some reason.
This change introduces explicit r->disable_not_modified flag instead,
which is set by ngx_http_upstream_process_headers().
Previous code in ngx_http_upstream_send_response() used last modified time
from r->headers_out.last_modified_time after the header filter chain was
already called. At this point, last_modified_time may be already cleared,
e.g., with SSI, resulting in incorrect last modified time stored in a
cache file. Fix is to introduce u->headers_in.last_modified_time instead.
Clearing of the r->headers_out.last_modified_time field if a response
isn't cacheable in ngx_http_upstream_send_response() was introduced
in 3b6afa999c2f, the commit to enable not modified filter for cacheable
responses. It doesn't make sense though, as at this point header was
already sent, and not modified filter was already executed. Therefore,
the line was removed to simplify code.
log->filter ("if" parameter) was uninitialized when the default value
was being used, which would lead to a crash (SIGSEGV) when access_log
directive wasn't specified in the configuration.
Zero-fill the whole structure instead of zeroing fields one-by-one
in order to prevent similar issues in the future.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Large allocations from a slab pool result in free page blocks being fragmented,
eventually leading to a situation when no further allocation larger than a page
size are possible from the pool. While this isn't a problem for nginx itself,
it is known to be bad for various 3rd party modules. Fix is to merge adjacent
blocks of free pages in the ngx_slab_free_pages() function.
Prodded by Wandenberg Peixoto and Yichun Zhang.
Since the type cast has precedence higher than the bit shift operator,
all values were truncated to 8 bits.
These macros are used to construct header block for SYN_REPLY frame on
platforms with strict alignment requirements. As a result, any response
that contains a header with name or value longer than 255 bytes was
corrupted on such platforms.
Do not taste the last parameter against directory, as otherwise it would
result in the trailing slash being cut from the parameter value.
Notably, this prevents an internal redirect to an empty URI
if the parameter is set to the literal slash:
location / { try_files $uri /; }
Previous workaround to avoid warnings on OS X due to deprecated system
OpenSSL library (introduced in a3870ea96ccd) no longer works, as
the MAC_OS_X_VERSION_MIN_REQUIRED macro is ignored on OS X 10.9
if a compiler used supports __attribute__(availability).
In particular, properly output partial match at the end of a subrequest
response (much like we do at the end of a response), and reset/set the
last_in_chain flag as appropriate.
Reported by KAWAHARA Masashi.
This fixes --with-file-aio support on systems that lack eventfd()
syscall, notably aarch64 Linux.
The syscall(SYS_eventfd) may still be necessary on systems that
have eventfd() syscall in the kernel but lack it in glibc, e.g.
as seen in the current CentOS 5 release.
Missed during introduction of the SMTP pipelining support (04e43d03e153,
1.5.6). Previously, the check wasn't needed as s->buffer was used directly
and the number of arguments didn't matter.
Reported by Svyatoslav Nikolsky.
If response is gzipped we can't recode response, but in case it's not
needed we still can add charset to Content-Type.
The r->ignore_content_encoding is dropped accordingly, charset with gzip_static
now properly works without any special flags.
The ngx_http_map_uri_to_path() function used clcf->regex to detect if
it's working within a location given by a regular expression and have
to replace full URI with alias (instead of a part matching the location
prefix). This is incorrect due to clcf->regex being false in implicit
locations created by if and limit_except.
Fix is to preserve relevant information in clcf->alias instead, by setting
it to NGX_MAX_SIZE_T_VALUE if an alias was specified in a regex location.
Handling of PROXY protocol for SPDY connection is currently implemented as
a SPDY state. And while nginx waiting for PROXY protocol data it continues
to process SPDY connection: initializes zlib context, sends control frames.
- Specification-friendly handling of invalid header block or special headers.
Such errors are not fatal for session and shouldn't lead to connection close;
- Avoid mix of NGX_HTTP_PARSE_INVALID_REQUEST/NGX_HTTP_PARSE_INVALID_HEADER.
The function just calls ngx_http_spdy_state_headers_skip() most of the time.
There was also an attempt of optimization to stop parsing if the client already
closed connection, but it looks strange and unfinished anyway.
Now ngx_http_spdy_state_protocol_error() is able to close stream,
so there is no need in a separate call for this.
Also fixed zero status code in logs for some cases.
The 7022564a9e0e changeset made ineffective workaround from 2464ccebdb52
to avoid NULL pointer dereference with "if". It is now restored by
moving the u->ssl_name initialization after the check.
Found by Coverity (CID 1210408).
Previous code failed to properly restore cf->conf_file in case of
ngx_close_file() errors, potentially resulting in double free of
cf->conf_file->buffer->start.
Found by Coverity (CID 1087507).
While managing big caches it is possible that expiring old cache items
in ngx_http_file_cache_expire() will take a while. Added a check for
ngx_quit / ngx_terminate to make sure cache manager can be terminated
while in ngx_http_file_cache_expire().
The ngx_http_proxy_rewrite_cookie() function expects the value of the
"Set-Cookie" header to be null-terminated, and for headers obtained
from proxied server it is usually true.
Now the ngx_http_proxy_rewrite() function preserves the null character
while rewriting headers.
This fixes accessing memory outside of rewritten value if both the
"proxy_cookie_path" and "proxy_cookie_domain" directives are used in
the same location.
There's a race condition between closing a stream by one endpoint
and sending a WINDOW_UPDATE frame by another. So it would be better
to just skip such frames for unknown streams, like is already done
for the DATA frames.
These directives allow to switch on Server Name Indication (SNI) while
connecting to upstream servers.
By default, proxy_ssl_server_name is currently off (that is, no SNI) and
proxy_ssl_name is set to a host used in the proxy_pass directive.
The SSL_CTX_set_cipher_list() may fail if there are no valid ciphers
specified in proxy_ssl_ciphers / uwsgi_ssl_ciphers, resulting in
SSL context leak.
In theory, ngx_pool_cleanup_add() may fail too, but this case is
intentionally left out for now as it's almost impossible and proper fix
will require changes to http ssl and mail ssl code as well.
This should prevent attempts of using pointer before it was checked, since
all modern compilers are able to spot access to uninitialized variable.
No functional changes.
Previously, an empty frame object was created for an output chain that contains
only sync or flush empty buffers. But since 39d7eef2e332 every DATA frame has
the flush flag set on its last buffer, so there's no need any more in additional
flush buffers in the output queue and they can be skipped.
Note that such flush frames caused an incorrect $body_bytes_sent value.
The SPDY draft 2 specification requires that if an endpoint receives a
control frame for a type it does not recognize, it must ignore the frame.
But the 3 and 3.1 drafts don't seem to declare any behavior for such case.
Then sticking with the previous draft in this matter looks to be right.
But previously, only 8 least significant bits of the type field were
parsed while the rest of 16 bits of the field were checked against zero.
Though there are no known frame types bigger than 255, this resulted in
inconsistency in handling of such frames: they were not recognized as
valid frames at all, and the connection was closed.
If start time is within the track but end time is out of it, error
"end time is out mp4 stts samples" is generated. However it's
better to ignore the error and output the track until its end.
The ngx_cacheline_size may be too low on some platforms, resulting
in unexpected hash build problems (as no collisions are tolerated due
to low bucket_size, and max_size isn't big enough to build a hash without
collisions). These problems aren't fatal anymore but nevertheless
need to be addressed.
The flag allows to suppress "ngx_slab_alloc() failed: no memory" messages
from a slab allocator, e.g., if an LRU expiration is used by a consumer
and allocation failures aren't fatal.
The flag is now used in the SSL session cache code, and in the limit_req
module.
The "ngx_quit" may be reset by the worker thread before it's seen
by a ngx_cache_manager_thread(), resulting in an infinite loop. Make
sure to test ngx_exiting as well.
This brings Cygwin compilation in line with other case-insensitive
systems (notably win32 and OS X) where one can force case sensitivity
using -DNGX_HAVE_CASELESS_FILESYSTEM=0.
Despite introducing start and end crop operations existing log
messages still mostly refer only to start. Logging is improved
to match both cases.
New debug logging is added to track entry count in atoms after
cropping.
Two format type mismatches are fixed as well.
When "start" value is equal to a track duration the request
fails with "time is out mp4 stts" like it did before track
duration check was added. Now such tracks are considered
short and skipped.
The SPDY/3.1 specification requires that the server must respond with
a 400 "Bad request" error if the sum of the data frame payload lengths
does not equal the size of the Content-Length header.
This also fixes "zero size buf in output" alert, that might be triggered
if client sends a greater than zero Content-Length header and closes
stream using the FIN flag with an empty request body.
There are a few cases in ngx_http_spdy_state_read_data() related to error
handling when ngx_http_spdy_state_skip() might be called with an inconsistent
state between *pos and sc->length, that leads to violation of frame layout
parsing and resuted in corruption of spdy connection.
Based on a patch by Xiaochen Wang.
Previously, only one case was checked: if there's more data to parse
in a r->header_in buffer, but the buffer can be filled to the end by
the last parsed entry, so we also need to check that there's no more
data to inflate.
If set, it means that response body is going to be in more than one buffer,
hence only range requests with a single range should be honored.
The flag is now used by mp4 and cacheable upstream responses, thus allowing
range requests of mp4 files with start/end, as well as range processing
on a first request to a not-yet-cached files with proxy_cache.
Notably this makes it possible to play mp4 files (with proxy_cache, or with
mp4 module) on iOS devices, as byte-range support is required by Apple.
Client address specified in the PROXY protocol header is now
saved in the $proxy_protocol_addr variable and can be used in
the realip module.
This is currently not implemented for mail.
Additionally, make sure to check for errors from ngx_http_parse_header_line()
call after joining saved parts. There shouldn't be any errors, though
check may help to catch bugs like missing f->split_parts reset.
Reported by Lucas Molas.
Previously r->header_size was used to store length for a part of
value that represents an individual already parsed HTTP header,
while r->header_end pointed to the end of the whole value.
Instead of storing length of a following name or value as pointer
to a potential end address (r->header_name_end and r->header_end)
that might be overflowed, now r->lowercase_index counter is used
to store remaining length of a following unparsed field.
It also fixes incorrect $body_bytes_sent value if a request is
closed while parsing of the request header. Since r->header_size
is intended for counting header size, thus abusing it for header
parsing purpose was certainly a bad idea.
If something like "error_page 400 @name" is used in a configuration,
a request could be passed to a named location without URI set, and this
in turn might result in segmentation faults or other bad effects
as most of the code assumes URI is set.
With this change nginx will catch such configuration problems in
ngx_http_named_location() and will stop request processing if URI
is not set, returning 500.
If a request is finalized in the first call to the
ngx_http_upstream_process_upgraded() function, e.g., because upstream
server closed the connection for some reason, in the second call
the u->peer.connection pointer will be null, resulting in segmentation
fault.
Fix is to avoid second direct call, and post event instead. This ensures
that ngx_http_upstream_process_upgraded() won't be called again if
a request is finalized.
The fix removes useless stsc entry in result mp4.
If start_sample == n then current stsc entry should be skipped
and the result stsc should start with the next entry.
The reason for that is start_sample starts from 0, not 1.
Previously, upstream's status code was overwritten with
cached response's status code when STALE or REVALIDATED
response was sent to the client.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The size of the priority field is increased by one bit in spdy/3,
and now it's a 3-bit field followed by 5 bits of unused space.
But a shift of these bits hasn't been adjusted in 39d7eef2e332
accordingly.
Linux returns EOPNOTSUPP for non-TCP sockets and ENOPROTOOPT for TCP
sockets, because getsockopt(TCP_FASTOPEN) is not implemented so far.
While there, lower the log level from ALERT to NOTICE to match other
getsockopt() failures.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
If "proxy_pass" is specified with variables, the resulting
hostname is looked up in the list of upstreams defined in
configuration. The search was case-sensitive, as opposed
to the case of "proxy_pass" specified without variables.
If seek position is within the last track chunk
and that chunk is standalone (stsc entry describes only
this chunk) such seek generates stsc seek error. The
problem is that chunk numbers start with 1, not with 0.
Mp4 module does not check movie and track durations when reading
file. Instead it generates errors when track metadata is shorter
than seek position. Now such tracks are skipped and movie duration
check is performed at file read stage.
Mp4 module does not allow seeks after the last key frame. Since
stss atom only contains key frames it's usually shorter than
other track atoms. That leads to stss seek error when seek
position is close to the end of file. The fix outputs empty
stss frame instead of generating error.
Backed out 05a56ebb084a, as it turns out that kernel can return connections
without any delay if syncookies are used. This basically means we can't
assume anything about connections returned with deferred accept set.
To solve original problem the 05a56ebb084a tried to solve, i.e. to don't
wait longer than needed if a connection was accepted after deferred accept
timeout, this patch changes a timeout set with setsockopt(TCP_DEFER_ACCEPT)
to 1 second, unconditionally. This is believed to be enough for speed
improvements, and doesn't imply major changes to timeouts used.
Note that before 2.6.32 connections were dropped after a timeout. Though
it is believed that 1s is still appropriate for kernels before 2.6.32,
as previously tcp_synack_retries controlled the actual timeout and 1s results
in more than 1 minute actual timeout by default.
If there is no SSI context in a given request at a given time,
the $date_local and $date_gmt variables used "%s" format, instead
of "%A, %d-%b-%Y %H:%M:%S %Z" documented as the default and used
if there is SSI module context and timefmt wasn't modified using
the "config" SSI command.
While use of these variables outside of the SSI evaluation isn't strictly
valid, previous behaviour is certainly inconsistent, hence the fix.
Even during execution of a request it is possible that there will be
no session available, notably in case of renegotiation. As a result
logging of $ssl_session_id in some cases caused NULL pointer dereference
after revision 97e3769637a7 (1.5.9). The check added returns an empty
string if there is no session available.
Read event on a client connection might have been disabled during
previous processing, and we at least need to handle events. Calling
ngx_http_upstream_process_upgraded() is a simpliest way to do it.
Notably this change is needed for select, poll and /dev/poll event
methods.
Previous version of this patch was posted here:
http://mailman.nginx.org/pipermail/nginx/2014-January/041839.html
Previously, it used to contain full session serialized instead of just
a session id, making it almost impossible to use the variable in a safe
way.
Thanks to Ivan Ristić.
It simplifies the code and allows easy reuse the same queue pointer to store
streams in various queues with different requirements. Future implementation
of SPDY/3.1 will take advantage of this quality.
The "length" value better corresponds with the specification and reduces
confusion about whether frame's header is included in "size" or not.
Also this change simplifies some parts of code, since in more cases the
length of frame is more useful than its actual size, especially considering
that the size of frame header is constant.
There is no need in separate "free" pointer and like it is for ngx_chain_t
the "next" pointer can be used. But after this change successfully handled
frame should not be accessed, so the frame handling cycle was improved to
store pointer to the next frame before processing.
Also worth noting that initializing "free" pointer to NULL in the original
code was surplus.
That code was based on misunderstanding of spdy specification about
configuration applicability in the SETTINGS frames. The original
interpretation was that configuration is assigned for the whole
SPDY connection, while it is only for the endpoint.
Moreover, the strange thing is that specification forbids multiple
entries in the SETTINGS frame with the same ID even if flags are
different. As a result, Chrome sends two SETTINGS frames: one with
its own configuration, and another one with configuration stored
for a server (when the FLAG_SETTINGS_PERSIST_VALUE flags were used
by the server).
To simplify implementation we refuse to use the persistent settings
feature and thereby avoid all the complexity related with its proper
support.
The "headers" is not a good term, since it is used not only to count
name/value pairs in the HEADERS block but to count SETTINGS entries too.
Moreover, one name/value pair in HEADERS can contain multiple http headers
with the same name.
No functional changes.
While processing a DATA frame, the link to related stream is stored in spdy
connection object as part of connection state. But this stream can be closed
between receiving parts of the frame.
Previously pool->current wasn't moved back to pool, resulting in blocks
not used for further allocations if pool->current was already moved at the
time of ngx_reset_pool(). Additionally, to preserve logic of moving
pool->current, the p->d.failed counters are now properly cleared. While
here, pool->chain is also cleared.
This change is essentially a nop with current code, but generally improves
things.
During the processing of input some control frames can be added to the queue.
And if there were no writing streams at the moment, these control frames might
be left unsent for a long time (or even forever).
This long delay is especially critical for PING replies since a client can
consider connection as broken and then resend exactly the same request over
a new connection, which is not safe in case of non-idempotent HTTP methods.
There is no reason to allocate it from connection pool that more like just
a bug especially since ngx_http_spdy_settings_frame_handler() already uses
sc->pool to free a chain.
The frame->stream pointer should always be initialized for control frames since
the check against it can be performed in ngx_http_spdy_filter_cleanup().
Parameters of ngx_http_spdy_filter_get_shadow() are changed from size_t to off_t
since the last call of the function may get size and offset from the rest of a
file buffer. This fixes possible data loss rightfully complained by MSVC on 32
bits systems where off_t is 8 bytes long while size_t is only 4 bytes.
The other two type casts are needed just to suppress warnings about possible
data loss also complained by MSVC but false positive in these cases.
False positive warning about the "cl" variable may be uninitialized in
the ngx_http_spdy_filter_get_data_frame() call was suppressed.
It is always initialized either in the "while" cycle or in the following
"if" condition since frame_size cannot be zero.
The "delayed" flag always should be set if there are unsent frames,
but this might not be the case if ngx_http_spdy_body_filter() was
called with NULL chain.
As a result, the "send_timeout" timer could be set on a stream in
ngx_http_writer(). And if the timeout occurred before all the stream
data has been sent, then the request was finalized with the "client
timed out" error.
It was used to prevent destroying of request object when there are unsent
frames in queue for the stream. Since it was incremented for each frame
and is only 8 bits long, so it was not very hard to overflow the counter.
Now the stream->queued counter is checked instead.
This adds support so it's possible to explicitly disable SSL Session
Tickets. In order to have good Forward Secrecy support either the
session ticket key has to be reloaded by using nginx' binary upgrade
process or using an external key file and reloading the configuration.
This directive adds another possibility to have good support by
disabling session tickets altogether.
If session tickets are enabled and the process lives for a long a time,
an attacker can grab the session ticket from the process and use that to
decrypt any traffic that occured during the entire lifetime of the
process.
If a request had an empty request body (with Content-Length: 0), and there
were preread data available (e.g., due to a pipelined request in the buffer),
the "zero size buf in output" alert might be logged while proxying the
request to an upstream.
Similar alerts appeared with client_body_in_file_only if a request had an
empty request body.
Not really a strict check (as X-Accel-Expires might be ignored or
contain invalid value), but quite simple to implement and better
than what we have now.
Fallback to synchronous sendfile() now only done on 3rd EBUSY without
any progress in a row. Not falling back is believed to be better
in case of occasional EBUSY, though protection is still needed to
make sure there will be no infinite loop.
This fixes content type set in stub_status and autoindex responses
to be usable in content type checks made by filter modules, such
as charset and sub filters.
There is no need to pass FLAG_FIN as a separate argument since it can always be
detected from the last_buf flag of the last frame buffer.
No functional changes.
Processing events from upstream connection can result in sending queued frames
from other streams. In this case such streams were not added to handling queue
and properly handled.
A global per connection flag was replaced by a per stream flag that indicates
currently sending stream while all other streams can be added to handling
queue.
Conditions for skipping ineligible peers are rewritten to make adding of new
conditions simpler and be in line with the "round_robin" and "least_conn"
modules. No functional changes.
Stricten response header checks: ensure that reserved bits are zeroes,
and that the opcode is "standard query".
Fixed the "zero-length domain name in DNS response" condition.
Renamed ngx_resolver_query_t to ngx_resolver_hdr_t as it describes
the header that is common to DNS queries and answers.
Replaced the magic number 12 by the size of the header structure.
The other changes are self-explanatory.
This flag in SPDY fake write events serves the same purposes as the "ready"
flag in real events, and it must be dropped if request needs to be handled.
Otherwise, it can prevent the request from finalization if ngx_http_writer()
was set, which results in a connection leak.
Found by Xiaochen Wang.
If c->read->ready was reset, but later some data were read from a socket
buffer due to a call to ngx_ssl_recv(), the c->read->ready flag should
be restored if not all data were read from OpenSSL buffers (as kernel
won't notify us about the data anymore).
More details are available here:
http://mailman.nginx.org/pipermail/nginx/2013-November/041178.html
The following new directives are introduced: proxy_cache_revalidate,
fastcgi_cache_revalidate, scgi_cache_revalidate, uwsgi_cache_revalidate.
Default is off. When set to on, they enable cache revalidation using
conditional requests with If-Modified-Since for expired cache items.
As of now, no attempts are made to merge headers given in a 304 response
during cache revalidation with headers previously stored in a cache item.
Headers in a 304 response are only used to calculate new validity time
of a cache item.
We should just call post_handler() when subrequest wants to read body, like
it happens for HTTP since rev. f458156fd46a. An attempt to init request body
for subrequests results in hang if the body was not already read.
Recent Linux versions started to return EOPNOTSUPP to getsockopt() calls
on unix sockets, resulting in log pollution on binary upgrade. Such errors
are silently ignored now.
The accept_filter and deferred options were not applied to sockets
that were added to configuration during binary upgrade cycle.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The 403 (Forbidden) should not overwrite 401 (Unauthorized) as the
latter should be returned with the WWW-Authenticate header to request
authentication by a client.
The problem could be triggered with 3rd party modules and the "deny"
directive, or with auth_basic and auth_request which returns 403
(in 1.5.4+).
Patch by Jan Marc Hoffmann.
Much like with other headers, "add_header Cache-Control $value;" no longer
results in anything added to response headers if $value evaluates to an
empty string.
In order to support key rollover, ssl_session_ticket_key can be defined
multiple times. The first key will be used to issue and resume Session
Tickets, while the rest will be used only to resume them.
ssl_session_ticket_key session_tickets/current.key;
ssl_session_ticket_key session_tickets/prev-1h.key;
ssl_session_ticket_key session_tickets/prev-2h.key;
Please note that nginx supports Session Tickets even without explicit
configuration of the keys and this feature should be only used in setups
where SSL traffic is distributed across multiple nginx servers.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The timeout set is used by OpenSSL as a hint for clients in TLS Session
Tickets. Previous code resulted in a default timeout (5m) used for TLS
Sessions Tickets if there was no session cache configured.
Prodded by Piotr Sikora.
With this change all such frames will be added in front of the output queue, and
will be sent first. It prevents HOL blocking when response with higher priority
is blocked by response with lower priority in the middle of the queue because
the order of their SYN_REPLY frames cannot be changed.
Proposed by Yury Kirpichev.
If an error occurs in a SPDY connection, the c->error flag is set on every fake
request connection, and its read or write event handler is called, in order to
finalize it. But while waiting for request headers, it was a no-op since the
read event handler had been set to ngx_http_empty_handler().
If an error occurs in a SPDY connection, the c->error flag is set on every fake
request connection, and its read or write event handler is called, in order to
finalize it. But while waiting for a request body, it was a no-op since the
read event handler ngx_http_request_handler() calls r->read_event_handler that
had been set to ngx_http_block_reading().
Basically, this does the following two changes (and corresponding
modifications of related code):
1. Does not reset session buffer unless it's reached it's end, and always
wait for LF to terminate command (even if we detected invalid command).
2. Record command name to make it available for handlers (since now we
can't assume that command starts from s->buffer->start).
A server MUST send greeting before other replies, while before this
change in case of smtp_greeting_delay violation the 220 greeting was
sent after several 503 replies to commands received before greeting,
resulting in protocol synchronization loss. Moreover, further commands
were accepted after the greeting.
While closing a connection isn't strictly RFC compliant (RFC 5321
requires servers to wait for a QUIT before closing a connection), it's
probably good enough for practial uses.
With previous code only part of u->buffer might be emptied in case
of special responses, resulting in partial responses seen by SSI set
in case of simple protocols, or spurious errors like "upstream sent
invalid chunked response" in case of complex ones.
This patch fixes incorrect handling of auto redirect in configurations
like:
location /0 { }
location /a- { }
location /a/ { proxy_pass ... }
With previously used sorting, this resulted in the following locations
tree (as "-" is less than "/"):
"/a-"
"/0" "/a/"
and a request to "/a" didn't match "/a/" with auto_redirect, as it
didn't traverse relevant tree node during lookup (it tested "/a-",
then "/0", and then falled back to null location).
To preserve locale use for non-ASCII characters on case-insensetive
systems, libc's tolower() used.
Location tree was always constructed using case-sensitive comparison, even
on case-insensitive systems. This resulted in incorrect operation if
uppercase letters were used in location directives. Notably, the
following config:
location /a { ... }
location /B { ... }
failed to properly map requests to "/B" into "location /B".
Found by using auth_basic.t from mdounin nginx-tests under valgrind.
==10470== Invalid write of size 1
==10470== at 0x43603D: ngx_crypt_to64 (ngx_crypt.c:168)
==10470== by 0x43648E: ngx_crypt (ngx_crypt.c:153)
==10470== by 0x489D8B: ngx_http_auth_basic_crypt_handler (ngx_http_auth_basic_module.c:297)
==10470== by 0x48A24A: ngx_http_auth_basic_handler (ngx_http_auth_basic_module.c:240)
==10470== by 0x44EAB9: ngx_http_core_access_phase (ngx_http_core_module.c:1121)
==10470== by 0x44A822: ngx_http_core_run_phases (ngx_http_core_module.c:895)
==10470== by 0x44A932: ngx_http_handler (ngx_http_core_module.c:878)
==10470== by 0x455EEF: ngx_http_process_request (ngx_http_request.c:1852)
==10470== by 0x456527: ngx_http_process_request_headers (ngx_http_request.c:1283)
==10470== by 0x456A91: ngx_http_process_request_line (ngx_http_request.c:964)
==10470== by 0x457097: ngx_http_wait_request_handler (ngx_http_request.c:486)
==10470== by 0x4411EE: ngx_epoll_process_events (ngx_epoll_module.c:691)
==10470== Address 0x5866fab is 0 bytes after a block of size 27 alloc'd
==10470== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==10470== by 0x43B251: ngx_alloc (ngx_alloc.c:22)
==10470== by 0x421B0D: ngx_malloc (ngx_palloc.c:119)
==10470== by 0x421B65: ngx_pnalloc (ngx_palloc.c:147)
==10470== by 0x436368: ngx_crypt (ngx_crypt.c:140)
==10470== by 0x489D8B: ngx_http_auth_basic_crypt_handler (ngx_http_auth_basic_module.c:297)
==10470== by 0x48A24A: ngx_http_auth_basic_handler (ngx_http_auth_basic_module.c:240)
==10470== by 0x44EAB9: ngx_http_core_access_phase (ngx_http_core_module.c:1121)
==10470== by 0x44A822: ngx_http_core_run_phases (ngx_http_core_module.c:895)
==10470== by 0x44A932: ngx_http_handler (ngx_http_core_module.c:878)
==10470== by 0x455EEF: ngx_http_process_request (ngx_http_request.c:1852)
==10470== by 0x456527: ngx_http_process_request_headers (ngx_http_request.c:1283)
==10470==
The same path names with different "data" context should not be allowed.
In particular it rejects configurations like this:
proxy_cache_path /var/cache/ keys_zone=one:10m max_size=1g inactive=5m;
proxy_cache_path /var/cache/ keys_zone=two:20m max_size=4m inactive=30s;
The SSL_CTX_load_verify_locations() may leave errors in the error queue
while returning success (e.g. if there are duplicate certificates in the file
specified), resulting in "ignoring stale global SSL error" alerts later
at runtime.
Casts between pointers and integers produce warnings on size mismatch. To
silence them, cast to (u)intptr_t should be used. Prevoiusly, casts to
ngx_(u)int_t were used in some cases, and several ngx_int_t expressions had
no casts.
As of now it's mostly style as ngx_int_t is defined as intptr_t.
On win32, time_t is 64 bits wide by default, and passing an ngx_msec_int_t
argument for %T format specifier doesn't work. This doesn't manifest itself
on other platforms as time_t and ngx_msec_int_t are usually of the same size.
Several warnings silenced, notably (ngx_socket_t) -1 is now checked
on socket operations instead of -1, as ngx_socket_t is unsigned on win32
and gcc complains on comparison.
With this patch, it's now possible to compile nginx using mingw gcc,
with options we normally compile on win32.
Several false positive warnings silenced, notably W8012 "Comparing
signed and unsigned" (due to u_short values promoted to int), and
W8072 "Suspicious pointer arithmetic" (due to large type values added
to pointers).
With this patch, it's now again possible to compile nginx using bcc32,
with options we normally compile on win32 minus ipv6 and ssl.
Precompiled headers are disabled as they lead to internal compiler errors
with long configure lines. Couple of false positive warnings silenced.
Various win32 typedefs are adjusted to work with Open Watcom C 1.9 headers.
With this patch, it's now again possible to compile nginx using owc386,
with options we normally compile on win32 minus ipv6 and ssl.
It was introduced in Linux 2.6.39, glibc 2.14 and allows to obtain
file descriptors without actually opening files. Thus made it possible
to traverse path with openat() syscalls without the need to have read
permissions for path components. It is effectively emulates O_SEARCH
which is missing on Linux.
O_PATH is used in combination with O_RDONLY. The last one is ignored
if O_PATH is used, but it allows nginx to not fail when it was built on
modern system (i.e. glibc 2.14+) and run with a kernel older than 2.6.39.
Then O_PATH is unknown to the kernel and ignored, while O_RDONLY is used.
Sadly, fstat() is not working with O_PATH descriptors till Linux 3.6.
As a workaround we fallback to fstatat() with the AT_EMPTY_PATH flag
that was introduced at the same time as O_PATH.
It is believed to be better than fallback to HTTP/0.9, because most of
the clients at present time support HTTP/1.0. It allows nginx to return
error response code for them in cases when it fail to parse request line,
and therefore fail to detect client protocol version.
Even if the client does not support HTTP/1.0, this assumption should not
cause any harm, since from the HTTP/0.9 point of view it still a valid
response.
Without u->header_sent set a special response might be generated following
an upgraded connection. The problem appeared in 1ccdda1f37f3 (1.5.3).
Catched by "header already sent" alerts in 1.5.4 after upstream timeouts.
This allows to approach "server_name" values specified below the
"valid_referers" directive when used within the "server_names" parameter, e.g.:
server_name example.org;
valid_referers server_names;
server_name example.com;
As a bonus, this fixes bogus error with "server_names" specified several times.
The server_name regexes are normally compiled for case-sensitive matching.
This violates case-insensitive obligations in the referer module. To fix
this, the host string is converted to lower case before matching.
Previously server_name regex was executed against the whole referer string
after dropping the scheme part. This could led to an improper matching, e.g.:
server_name ~^localhost$;
valid_referers server_names;
Referer: http://localhost/index.html
It was changed to look only at the hostname part.
The server_name regexes are separated into another array to not clash with
regular regexes.
If Content-Length header is not set, and the image size is larger than the
buffer size, client will hang until a timeout occurs.
Now NGX_HTTP_UNSUPPORTED_MEDIA_TYPE is returned immediately.
diff -r d1403de41631 -r 4fae04f332b4
src/http/modules/ngx_http_image_filter_module.c
Missing call to ngx_http_run_posted_request() resulted in a main request hang
if subrequest's ssl handshake with an upstream server failed for some reason.
Reported by Aviram Cohen.
While ngx_get_full_name() might have a bit more descriptive arguments,
the ngx_conf_full_name() is generally easier to use when parsing
configuration and limits exposure of cycle->prefix / cycle->conf_prefix
details.
They refer to the same socket descriptor as our real connection, and
deleting them will stop processing of the connection.
Events of fake connections must not be activated, and if it happened there
is nothing we can do. The whole processing should be terminated as soon as
possible, but it is not obvious how to do this safely.
A quote from SPDY draft 2 specification: "The length of each name and
value must be greater than zero. A receiver of a zero-length name or
value must send a RST_STREAM with code PROTOCOL error."
But it appears that Chrome browser allows sending requests over SPDY/2
connection using JavaScript that contain headers with empty values.
For better compatibility across SPDY clients and to be compliant with
HTTP, such headers are no longer rejected.
Also, it is worth noting that in SPDY draft 3 the statement has been
changed so that it permits empty values for headers.
It was broken in 8e446a2daf48 when the NGX_SENDFILE_LIMIT constant was added
to ngx_linux_sendfile_chain.c having the same name as already defined one in
ngx_linux_config.h.
The newer is needed to overcome a bug in old Linux kernels by limiting the
number of bytes to send per sendfile() syscall. The older is used with
sendfile() on ancient kernels that works with 32-bit offsets only.
One of these renamed to NGX_SENDFILE_MAXSIZE.
When matching a compiled regex against value in the "Referer" header field,
the length was calculated incorrectly for strings that start from "https://".
This might cause matching to fail for regexes with end-of-line anchors.
Patch by Liangbin Li.
In ngx_*_sendfile_chain() when calculating pointer to a first
non-zero sized buf, use "in" as iterator. This fixes processing
of zero sized buf(s) after EINTR. Otherwise function can return
zero sized buf to caller, and later ngx_http_write_filter()
logs warning.
If a relative path is set by variables, then the ngx_conf_full_name()
function was called while processing requests, which causes allocations
from the cycle pool.
A new function that takes pool as an argument was introduced.
This is done by passing AI_ADDRCONFIG to getaddrinfo().
On Linux, setting net.ipv6.conf.all.disable_ipv6 to 1 will now be
respected.
On FreeBSD, AI_ADDRCONFIG filtering is currently implemented by
attempting to create a datagram socket for the corresponding family,
which succeeds even if the system doesn't in fact have any addresses
of that family configured. That is, if the system with IPv6 support
in the kernel doesn't have IPv6 addresses configured, AI_ADDRCONFIG
will filter out IPv6 only inside a jail without IPv6 addresses or
with IPv6 disabled.
Though there are several MIME types commonly used for JavaScript nowadays,
the most common being "text/javascript", "application/javascript", and
currently used by nginx "application/x-javascript", RFC 4329 prefers
"application/javascript".
The "charset_types" directive's default value was adjusted accordingly.
As per perlxs, C preprocessor directives should be at the first
non-whitespace of a line to avoid interpreting them as comments.
#if and #endif are moved so that there are no blank lines before them
to retain them as part of the function body.
Previously, after sending a header we always sent a last buffer and
finalized a request with code 0, even in case of errors. In some cases
this resulted in a loss of ability to detect the response wasn't complete
(e.g. if Content-Length was removed from a response by gzip filter).
This change tries to propogate to a client information that a response
isn't complete in such cases. In particular, with this change we no longer
pretend a returned response is complete if we wasn't able to create
a temporary file.
If an error code suggests the error wasn't fatal, we flush buffered data
and disable keepalive, then finalize request normally. This allows to to
propogate information about a problem to a client, while still sending all
the data we've got from an upstream.
No semantic changes expected, though some checks are done differently.
In particular, the r->cached flag is no longer explicitly checked. Instead,
we relay on u->header_sent not being set if a response is sent from
a cache.
The NGX_HTTP_CLIENT_CLOSED_REQUEST code is allowed to happen after we
started sending a response (much like NGX_HTTP_REQUEST_TIME_OUT), so there
is no need to reset response code to 0 in this case.
Checks were added to both buffered and unbuffered code paths to detect
and complain if a response is incomplete. Appropriate error codes are
now passed to ngx_http_upstream_finalize_request().
With this change in unbuffered mode we now use u->length set to -1 as an
indicator that EOF is allowed per protocol and used to indicate response
end (much like its with p->length in buffered mode). Proxy module was
changed to set u->length to 1 (instead of previously used -1) in case of
chunked transfer encoding used to comply with the above.
That is, by default we assume that response end is signalled by
a connection close. This seems to be better default, and in line
with u->pipe->length behaviour.
Memcached module was modified accordingly.
In case of upstream eof, only responses with u->pipe->length == -1
are now cached/stored. This ensures that unfinished chunked responses
are not cached.
Note well - previously used checks for u->headers_in.content_length_n are
preserved. This provides an additional level of protection if protol data
disagree with Content-Length header provided (e.g., a FastCGI response
is sent with wrong Content-Length, or an incomple SCGI or uwsgi response),
as well as protects from storing of responses to HEAD requests. This should
be reconsidered if we'll consider caching of responses to HEAD requests.
There is no real difference from previously used 0 as NGX_HTTP_* will
become 0 in ngx_http_upstream_finalize_request(), but the change
preserves information about a timeout a bit longer. Previous use of
ETIMEDOUT in one place was just wrong.
Note well that with cacheable responses there will be a difference
(code in ngx_http_upstream_finalize_request() will store the error
in cache), though this change doesn't touch cacheable case.
Previously, ngx_http_upstream_finalize_request(0) was used in most
cases after errors. While with current code there is no difference,
use of NGX_ERROR allows to pass a bit more information into
ngx_http_upstream_finalize_request().
In all cases ngx_http_upstream_finalize_request() with NGX_ERROR now used.
Previously used NGX_HTTP_INTERNAL_SERVER_ERROR in the subrequest in memory
case don't cause any harm, but inconsistent with other uses.
With previous code the p->temp_file->offset wasn't adjusted if a temp
file was written by the code in ngx_event_pipe_write_to_downstream()
after an EOF, resulting in cache not being used with empty scgi and uwsgi
responses with Content-Length set to 0.
Fix it to call ngx_event_pipe_write_chain_to_temp_file() there instead
of calling ngx_write_chain_to_temp_file() directly.
Previous code called ngx_http_finalize_request() with rc = 0. This is
ok if a response status was already set, but resulted in "000" being
logged if it wasn't. In particular this happened with limit_req
if a connection was prematurely closed during limit_req delay.
After a failed partial match we now check if there is another partial
match in previously matched substring to fix cases like "aab" in "aaab".
The ctx->saved string is now always sent if it's present on return
from the ngx_http_sub_parse() function (and reset accordingly). This
allows to release parts of previously matched data.
If a pattern was partially matched at a response end, partially matched
string wasn't send. E.g., a response "fo" was truncated to an empty response
if partially mathed by a pattern "foo".
It is possible to send FLAG_FIN in additional empty data frame, even if it is
known from the content-length header that request body is empty. And Firefox
actually behaves like this (see ticket #357).
To simplify code we sacrificed our microoptimization that did not work right
due to missing check in the ngx_http_spdy_state_data() function for rb->buf
set to NULL.
The exsltRegisterAll() needs to be called before XSLT stylesheets
are compiled, else stylesheet compilation hooks will not work. This
change fixes EXSLT Functions extension.
Currently this flag is needed for epoll and rtsig, and though these methods
usually present on different platforms than kqueue, nginx can be compiled to
support all of them.
The call to ngx_sock_ntop() in ngx_connection_local_sockaddr() might be
performed with the uninitialized "len" variable. The fix is to initialize
variable to the size of corresponding socket address type.
The issue was introduced in commit 05ba5bce31e0.
On Linux, sockaddr length is required to process unix socket addresses properly
due to unnamed sockets (which don't have sun_path set at all) and abstract
namespace sockets.
Minimal data length we expect for further calls was calculated incorrectly
if parsing stopped right after parsing chunk size. This might in theory
affect clients and/or backends using LF instead of CRLF.
Patch by Dmitry Popov.
On Linux x32 inclusion of sys/sysctl.h produces an error. As sysctl() is
only used by rtsig event method code, which is legacy and not compiled
in by default on modern linuxes, the sys/sysctl.h file now only included
if rtsig support is enabled.
Based on patch by Serguei I. Ivantsov.
When several "error_log" directives are specified in the same configuration
block, logs are written to all files with a matching log level.
All logs are stored in the singly-linked list that is sorted by log level in
the descending order.
Specific debug levels (NGX_LOG_DEBUG_HTTP,EVENT, etc.) are not supported
if several "error_log" directives are specified. In this case all logs
will use debug level that has largest absolute value.
The cycle->new_log->log_level should only be initialized by ngx_init_cycle()
if no error logs were found in the configuration. This move allows to get rid
of extra initialization in ngx_error_log().
Valgrind complains if we pass uninitialized memory to a syscall:
==36492== Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
==36492== at 0x6B5E6A: sendmsg (in /usr/lib/system/libsystem_kernel.dylib)
==36492== by 0x10004288E: ngx_signal_worker_processes (ngx_process_cycle.c:527)
==36492== by 0x1000417A7: ngx_master_process_cycle (ngx_process_cycle.c:203)
==36492== by 0x100001F10: main (nginx.c:410)
==36492== Address 0x7fff5fbff71c is on thread 1's stack
Even initialization of all members of the structure passed isn't enough, as
there is padding which still remains uninitialized and results in Valgrind
complaint. Note there is no real problem here as data from uninitialized
memory isn't used.
Valgrind intercepts SIGUSR2 in some cases, and nginx might not be able to
start due to sigaction() failure. If compiled with NGX_VALGRIND defined,
we now ignore the failure of sigaction().
If "stderr" was specified in one of the "error_log" directives,
stderr is not redirected to the first error_log on startup,
configuration reload, and reopening log files.
On win32 stderr was not redirected into a file specified by "error_log"
while reopening files. Fix is to use platform-independent functions to
work with stderr, as already used by ngx_init_cycle() and main() since
rev. d8316f307b6a.
Use of accept mutex on win32 may result in a deadlock if there are multiple
worker_processes configured and the mutex is grabbed by a process which
can't accept connections.
The parameter is mostly identical to http_404, and is expected to
be used in similar situations. The 403 code might be returned by
a backend instead of 404 on initial sync of new directories with rsync.
See here for feature request and additional details:
http://mailman.nginx.org/pipermail/nginx-ru/2013-April/050920.html
It is now a syntax error if tokens passed to a custom configuration
handler are terminated by "{".
The following incorrect configuration is now properly rejected:
map $v $v2 {
a b {
c d {
e f {
}
An invalid memcached reply that started with '\n' could cause
segmentation fault.
An invalid memcached reply "VALUE / 0 2\r?ok\r\nEND\r\n" was
considered as a valid response.
In addition, if memcached reports that the key was not found,
set u->headers_in.content_length_n to 0. This ensures that
ngx_http_memcached_filter() will not be called while previous
code relied on always intercepting 404. Initialization of
ctx->rest was moved to where it belongs.
Due to peer->checked always set since rev. c90801720a0c (1.3.0)
by round-robin and least_conn balancers (ip_hash not affected),
the code in ngx_http_upstream_free_round_robin_peer() function
incorrectly reset peer->fails too often.
Reported by Dmitry Popov,
http://mailman.nginx.org/pipermail/nginx-devel/2013-May/003720.html
Due to a bad argument list, nginx worker would crash (SIGSEGV) while
trying to log the fact that it received OCSP response with "revoked"
or "unknown" certificate status.
While there, fix similar (but non-crashing) error a few lines above.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
There are two significant changes in this patch:
1) The <= 0 comparison is done with a signed type. This fixes the case
of ngx_time() being larger than r->lingering_time.
2) Calculation of r->lingering_time - ngx_time() is now always done
in the ngx_msec_t type. This ensures the calculation is correct
even if time_t is unsigned and differs in size from ngx_msec_t.
Thanks to Lanshun Zhou.
Previously, input pattern was kept only for regular expressions
with named captures, which resulted in error log entries without
input pattern for PCRE errors that occured while processing
regular expressions without them.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The $proxy_internal_body_length value might change during request lifetime,
notably if proxy_set_body used, and use of a cached value might result in
incorrect upstream requests.
Patch by Lanshun Zhou.
As of now, it allows to better control bandwidth limiting from additional
modules. It is also expected to be used to add variables support to
the limit_rate_after directive.
If nginx was compiled without --with-http_ssl_module, but with some
other module which uses OpenSSL (e.g. --with-mail_ssl_module), insufficient
preprocessor check resulted in build failure. The problem was introduced
by e0a3714a36f8 (1.3.14).
Reported by Roman Arutyunyan.
This is to avoid setting the TCP_NODELAY flag on SPDY socket in
ngx_http_upstream_send_response(). The latter works per request,
but in SPDY case it might affect other streams in connection.
As of 1.3.9, chunked request body may be available with
r->headers_in.content_length_n <= 0. Additionally, request body
may be in multiple buffers even if r->request_body_in_single_buf
was requested.
Dependancy tracking introduced in r5169 were not handled absolute path
names properly. Absolute names might appear in CORE_DEPS if --with-openssl
or --with-pcre configure arguments are used to build OpenSSL/PCRE
libraries.
Additionally, revert part of r5169 to set NGX_INCS from Makefile
variables. Makefile variables have $ngx_include_opt in them, which
might result in wrong include paths being used. As a side effect,
this also restores build with --with-http_perl_module and --without-http
at the same time.
Before 1.3.9 an attempt to read body in a subrequest only caused problems
if body wasn't already read or discarded in a main request. Starting with
1.3.9 it might also cause problems if body was discarded by a main request
before subrequest start.
Fix is to just ignore attempts to read request body in a subrequest, which
looks like right thing to do anyway.
We generate both read and write events if an error event was returned by
port_getn() without POLLIN/POLLOUT, but we should not try to handle inactive
events, they may even have no handler.
Stale write event may happen if read and write events was reported both,
and processing of the read event closed descriptor.
In practice this might result in "sendfilev() failed (134: ..." or
"writev() failed (134: ..." errors when switching to next upstream server.
See report here:
http://mailman.nginx.org/pipermail/nginx/2013-April/038421.html
To avoid further breaks it's now done properly, all the dependencies
are now passed to Makefile.PL. While here, fixed include list passed to
Makefile.PL to use Makefile variables rather than a list expanded during
configure.
Problems with setsockopt(TCP_NODELAY) and setsockopt(TCP_NOPUSH), as well
as sendfile() syscall on Solaris, are specific to UNIX-domain sockets.
Other address families, i.e. AF_INET and AF_INET6, are fine.
On Win32 platforms 0 is used to indicate errors in file operations, so
comparing against -1 is not portable.
This was not much of an issue in patched code, since only ngx_fd_info() test
is actually reachable on Win32 and in worst case it might result in bogus
error log entry.
Patch by Piotr Sikora.
Sorting of upstream servers by their weights is not required by
current balancing algorithms.
This will likely change mapping to backends served by ip_hash
weighted upstreams.
And corresponding variable $connections_waiting was added.
Previously, waiting connections were counted as the difference between
active connections and the sum of reading and writing connections.
That made it impossible to count more than one request in one connection
as reading or writing (as is the case for SPDY).
Also, we no longer count connections in handshake state as waiting.
This should improve behavior under deficiency of connections.
Since SSL handshake usually takes significant amount of time,
we exclude connections from reusable queue during this period
to avoid premature flush of them.
If proxy_pass to a host with dynamic resolution was used to handle
a subrequest, and host resolution failed, the main request wasn't run
till something else happened on the connection. E.g. request to "/zzz"
with the following configuration hanged:
addition_types *;
resolver 8.8.8.8;
location /test {
set $ihost xxx;
proxy_pass http://$ihost;
}
location /zzz {
add_after_body /test;
return 200 "test";
}
Report and original version of the patch by Lanshun Zhou,
http://mailman.nginx.org/pipermail/nginx-devel/2013-March/003476.html.
Code to reuse of r->request_body->buf in upstream module assumes it's
dedicated buffer, hence after 1.3.9 (r4931) it might reuse r->header_in
if client_body_in_file_only was set, resulting in original request
corruption. It is considered to be safer to always create a dedicated
buffer for rb->bufs to avoid such problems.
After introduction of chunked request body handling in 1.3.9 (r4931),
r->request_body->bufs buffers have b->start pointing to original buffer
start (and b->pos pointing to real data of this particular buffer).
While this is ok as per se, it caused bad things (usually original request
headers included before the request body) after reinit of the request
chain in ngx_http_upstream_reinit() while sending the request to a next
upstream server (which used to do b->pos = b->start for each buffer
in the request chain).
Patch by Piotr Sikora.
If c->recv() returns 0 there is no sense in using ngx_socket_errno for
logging, its value meaningless. (The code in question was copied from
ngx_http_keepalive_handler(), but ngx_socket_errno makes sense there as it's
used as a part of ECONNRESET handling, and the c->recv() call is preceeded
by the ngx_set_socket_errno(0) call.)
In r2411 setting of NGX_HTTP_GZIP_BUFFERED in c->buffered was moved from
ngx_http_gzip_filter_deflate_start() to ngx_http_gzip_filter_buffer() since
it was always called first. But in r2543 the "postpone_gzipping" directive
was introduced, and if postponed gzipping is disabled (the default setting),
ngx_http_gzip_filter_buffer() is not called at all.
We must always set NGX_HTTP_GZIP_BUFFERED after the start of compression
since there is always a trailer that is buffered.
There are no known cases when it leads to any problem with current code.
But we already had troubles in upcoming SPDY implementation.
Not only this is useful for the upcoming SPDY support, but it can
also help to improve HTTPS performance by enabling TLS False Start
in Chrome/Chromium browsers [1]. So, we always enable NPN for HTTPS
if it is supported by OpenSSL.
[1] http://www.imperialviolet.org/2012/04/11/falsestart.html
The c->single_connection was intended to be used as lock mechanism
to serialize modifications of request object from several threads
working with client and upstream connections. The flag is redundant
since threads in nginx have never been used that way.
In Linux 2.6.32, TCP_DEFER_ACCEPT was changed to accept connections
after the deferring period is finished without any data available.
(Reading from the socket returns EAGAIN in this case.)
Since in nginx TCP_DEFER_ACCEPT is set to "post_accept_timeout", we
do not need to wait longer if deferred accept returns with no data.
Previously, only the first request in a connection used timeout
value from the "client_header_timeout" directive while reading
header. All subsequent requests used "keepalive_timeout" for
that.
It happened because timeout of the read event was set to the
value of "keepalive_timeout" in ngx_http_set_keepalive(), but
was not removed when the next request arrived.
Previously, we always created an object and logged 400 (Bad Request)
in access log if a client closed connection without sending any data.
Such a connection was counted as "reading".
Since it's common for modern browsers to behave like this, it's no
longer considered an error if a client closes connection without
sending any data, and such a connection will be counted as "waiting".
Now, we do not log 400 (Bad Request) and keep memory footprint as
small as possible.
Previously, it was allocated from a connection pool and
was selectively freed for an idle keepalive connection.
The goal is to put coupled things in one chunk of memory,
and to simplify handling of request objects.
According to RFC 6066, client is not supposed to request a different server
name at the application layer. Server implementations that rely upon these
names being equal must validate that a client did not send a different name
in HTTP request. Current versions of Apache HTTP server always return 400
"Bad Request" in such cases.
There exist implementations however (e.g., SPDY) that rely on being able to
request different host names in one connection. Given this, we only reject
requests with differing host names if verification of client certificates
is enabled in a corresponding server configuration.
An example of configuration that might not work as expected:
server {
listen 433 ssl default;
return 404;
}
server {
listen 433 ssl;
server_name example.org;
ssl_client_certificate org.cert;
ssl_verify_client on;
}
server {
listen 433 ssl;
server_name example.com;
ssl_client_certificate com.cert;
ssl_verify_client on;
}
Previously, a client was able to request example.com by presenting
a certificate for example.org, and vice versa.
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 multiple "Cache-Control" headers are sent to a client,
multiple values in $sent_http_cache_control were incorrectly
split by a semicolon. Now they are split by a comma.
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).
In case of fully populated SSL session cache with no memory left for
new allocations, ngx_ssl_new_session() will try to expire the oldest
non-expired session and retry, but only in case when slab allocation
fails for "cached_sess", not when slab allocation fails for either
"sess_id" or "id", which can happen for number of reasons and results
in new session not being cached.
Patch fixes this by adding retry logic to "sess_id" & "id" allocations.
Patch by Piotr Sikora.
It was added in r2717 and no longer needed since r2721,
where the termination was added to ngx_shm_alloc() and
ngx_init_zone_pool(). So then it only corrupts error
messages about ivalid zones.
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.
Note: use of {SHA} passwords is discouraged as {SHA} password scheme is
vulnerable to attacks using rainbow tables. Use of {SSHA}, $apr1$ or
crypt() algorithms as supported by OS is recommended instead.
The {SHA} password scheme support is added to avoid the need of changing
the scheme recorded in password files from {SHA} to {SSHA} because such
a change hides security problem with {SHA} passwords.
Patch by Louis Opter, with minor changes.
If fastcgi end request record was split between several network packets,
with fastcgi_keep_conn it was possible that connection was saved in incorrect
state (e.g. with padding bytes not yet read).
Checks for f->padding before state transitions make code hard to follow,
remove them and make sure we always do another loop iteration after
f->state is set to ngx_http_fastcgi_st_padding.
With fastcgi_keep_conn it was possible that connection was closed after
FCGI_STDERR record with zero padding and without any further data read yet.
This happended as f->state was set to ngx_http_fastcgi_st_padding and then
"break" happened, resulting in p->length being set to f->padding, i.e. 0
(which in turn resulted in connection close).
Fix is to make sure we continue the loop after f->state is set.
After introduction of chunked request body reading support in 1.3.9 (r4931),
the rb->bufs wasn't set if request body was fully preread while calling the
ngx_http_read_client_request_body() function.
Reported by Yichun Zhang (agentzh).
Missing calls to ngx_handle_write_event() and ngx_handle_read_event()
resulted in a CPU hog during SSL handshake if an level-triggered event
method (e.g. select) was used.
According to documentation, calling SSL_write() with num=0 bytes to be sent
results in undefined behavior.
We don't currently call ngx_ssl_send_chain() with empty chain and buffer.
This check handles the case of a chain with total data size that is
a multiple of NGX_SSL_BUFSIZE, and with the special buffer at the end.
In practice such cases resulted in premature connection close and critical
error "SSL_write() failed (SSL:)" in the error log.
The "secure_link_secret" directive was always inherited from the outer
configuration level even when "secure_link" and "secure_link_md5" were
specified on the inner level.
A POLLERR signalled by poll() without POLLIN/POLLOUT, as seen on
Linux, would generate both read and write events, but there's no
write event handler for resolver events. A fix is to only call
event handler of an active event.
Before the patch if proxy_method was specified at http{} level the code
to add trailing space wasn't executed, resulting in incorrect requests
to upstream.
The "proxy_bind", "fastcgi_bind", "uwsgi_bind", "scgi_bind" and
"memcached_bind" directives are now inherited; inherited value
can be reset by the "off" parameter. Duplicate directives are
now detected. Parameter value can now contain variables.
Upstreams created by "proxy_pass" with IP address and no port were
broken in 1.3.10, by not initializing port in u->sockaddr.
API change: ngx_parse_url() was modified to always initialize port
(in u->sockaddr and in u->port), even for the u->no_resolve case;
ngx_http_upstream() and ngx_http_upstream_add() were adopted.
The patch saves one EC_KEY_generate_key() call per server{} block by
informing OpenSSL about SSL_OP_SINGLE_ECDH_USE we are going to use before
the SSL_CTX_set_tmp_ecdh() call.
For a configuration file with 10k simple server{} blocks with SSL enabled
this change reduces startup time from 18s to 5s on a slow test box here.
Uninitialized pointer may result in arbitrary segfaults if access_log is used
without buffer and without variables in file path.
Patch by Tatsuhiko Kubo (ticket #268).
Previously, "default" was equivalent to specifying 0.0.0.0/0, now
it's equivalent to specifying both 0.0.0.0/0 and ::/0 (if support
for IPv6 is enabled) with the same value.
The code refactored in a way to call custom handler that can do appropriate
cleanup work (if any), like flushing buffers, finishing compress streams,
finalizing connections to log daemon, etc..
Previously a new buffer was allocated for every "access_log" directive with the
same file path and "buffer=" parameters, while only one buffer per file is used.
The crypt_r() function returns NULL on errors, check it explicitly instead
of assuming errno will remain 0 if there are no errors (per POSIX, the
setting of errno after a successful call to a function is unspecified
unless the description of that function specifies that errno shall not
be modified).
Additionally, dropped unneeded ngx_set_errno(0) and fixed error handling
of memory allocation after normal crypt(), which was inapropriate and
resulted in null pointer dereference on allocation failures.
Configurations like
location /i/ {
image_filter resize 200 200;
image_filter rotate 180;
location /i/foo/ {
image_filter resize 200 200;
}
}
resulted in rotation incorrectly applied in the location /i/foo, without
any way to clear it. Fix is to handle conf->angle/conf->acv consistently
with other filter variables and do not try to inherit them if there are
transformations defined for current location.
The image_filter_jpeg_quality, image_filter_sharpen and "image_filter rotate"
were inherited incorrectly if a directive with variables was defined, and
then redefined to a literal value, i.e. in configurations like
image_filter_jpeg_quality $arg_q;
location / {
image_filter_jpeg_quality 50;
}
Patch by Ian Babrou, with minor changes.
This includes "debug_connection", upstreams, "proxy_pass", etc.
(ticket #92)
To preserve compatibility, "listen" specified with a domain name
selects the first IPv4 address, if available. If not available,
the first IPv6 address will be used (ticket #186).
The URL parsing code is not expected to initialize port from default port
when in "no_resolve" mode. This got broken in r4671 for the case of IPv6
literals.
The ngx_write_fd() and ngx_read_fd() functions return -1 in case of error,
so the incorrect comparison with NGX_FILE_ERROR (which is 0 on windows
platforms) might result in inaccurate error message in the error log.
Also the ngx_errno global variable is being set only if the returned value
is -1.
An incorrect memLevel (lower than 1) might be passed to deflateInit2() if the
"gzip_hash" directive is set to a value less than the value of "gzip_window"
directive. This resulted in "deflateInit2() failed: -2" alert and an empty
reply.
Configuration like
location / {
set $true 1;
if ($true) {
proxy_pass http://backend;
}
if ($true) {
# nothing
}
}
resulted in segmentation fault due to NULL pointer dereference as the
upstream configuration wasn't initialized in an implicit location created
by the last if(), but the r->content_handler was set due to first if().
Instead of committing a suicide by dereferencing a NULL pointer, return
500 (Internal Server Error) in such cases, i.e. if uscf is NULL. Better
fix would be to avoid such cases by fixing the "if" directive handling,
but it's out of scope of this patch.
Prodded by Piotr Sikora.
This will result in alphabetical sorting of included files if
the "include" directive with wildcards is used.
Note that the behaviour is now different from that on Windows, where
alphabetical sorting is not guaranteed for FindFirsFile()/FindNextFile()
(used to be alphabetical on NTFS, but not on FAT).
Approved by Igor Sysoev, prodded by many.
Catched by dav_chunked.t on Solaris. In released versions this might
potentially result in corruption of complex protocol responses if they
were written to disk and there were more distinct buffers than IOV_MAX
in a single write.
If write events are not blocked, an extra write event might happen for
various reasons (e.g. as a result of a http pipelining), resulting in
incorrect body being passed to a post handler.
The problem manifested itself with the dav module only, as this is
the only module which reads the body from a content phase handler (in
contrast to exclusive content handlers like proxy). Additionally, dav
module used to dump core in such situations due to ticket #238.
See reports here:
http://mailman.nginx.org/pipermail/nginx-devel/2012-November/002981.htmlhttp://serverfault.com/questions/449195/nginx-webdav-server-with-auth-request
While discarding chunked request body in some cases after detecting
request body corruption no error was returned, while it was possible
to correctly return 400 Bad Request. If error is detected too late,
make sure to properly close connection.
Additionally, in ngx_http_special_response_handler() don't return body
of 500 Internal Server Error to a client if ngx_http_discard_request_body()
fails, but disable keepalive and continue.
Even if there is no preread data, make sure to always call
ngx_http_discard_request_body_filter() in case of chunked request
body to initialize r->headers_in.content_length_n for later use.
nginx doesn't allow the same shared memory zone to be used for different
purposes, but failed to check this on reconfiguration. If a shared memory
zone was used for another purpose in the new configuration, nginx attempted
to reuse it and crashed.
An attempt to call ngx_handle_read_event() before actually reading
data from a socket might result in read event being disabled, which is
wrong. Catched by body.t test on Solaris.
The r->main->count reference counter was always incremented in
ngx_http_read_client_request_body(), while it is only needs to be
incremented on positive returns.
The $request_body variable was assuming there can't be more than two
buffers. While this is currently true due to request body reading
implementation details, this is not a good thing to depend on and may
change in the future.
It is not about "Method" but a generic message, and is expected to be used
e.g. if specified Transfer-Encoding is not supported. Fixed message to
match RFC 2616.
Additionally, disable keepalive on such errors as we won't be able to read
request body correctly if we don't understand Transfer-Encoding used.
If request body reading happens with different options it's possible
that there will be no r->request_body->temp_file available (or even
no r->request_body available if body was discarded). Return internal
server error in this case instead of committing suicide by dereferencing
a null pointer.
Pending EOF might be reported on both read and write events, whichever
comes first, so check both of them.
Patch by Yichun Zhang (agentzh), slightly modified.
If an upstream block was defined with the only server marked as
"down", e.g.
upstream u {
server 127.0.0.1:8080 down;
}
an attempt was made to contact the server despite the "down" flag.
It is believed that immediate 502 response is better in such a
case, and it's also consistent with what is currently done in case
of multiple servers all marked as "down".
Input filter might free a buffer if there is no data in it, and in case
of first buffer (used for cache header and request header, aka p->buf_to_file)
this resulted in cache corruption. Buffer memory was reused to read upstream
response before headers were written to disk.
Fix is to avoid moving pointers in ngx_event_pipe_add_free_buf() to a buffer
start if we were asked to free a buffer used by p->buf_to_file.
This fixes occasional cache file corruption, usually resulted
in "cache file ... has md5 collision" alerts.
Reported by Anatoli Marinov.
