The module now supports recursive search of client address through
the chain of trusted proxies, controlled by the "real_ip_recursive"
directive (closes#2). It also gets full IPv6 support (closes#44)
and canonical value of the $client_addr variable on address change.
Example:
real_ip_header X-Forwarded-For;
set_real_ip_from 127.0.0.0/8;
set_real_ip_from ::1;
set_real_ip_from unix:;
real_ip_recursive on;
On input it takes an original address, string in the X-Forwarded-For format
and its length, list of trusted proxies, and a flag indicating to perform
the recursive search. On output it returns NGX_OK and the "deepest" valid
address in a chain, or NGX_DECLINED. It supports AF_INET and AF_INET6.
Additionally, original address and/or proxy may be specified as AF_UNIX.
Due to weight being set to 0 for down peers, order of peers after sorting
wasn't the same as without the "down" flag (with down peers at the end),
resulting in client rebalancing for clients on other servers. The only
rebalancing which should happen after adding "down" to a server is one
for clients on the server.
The problem was introduced in r1377 (which fixed endless loop by setting
weight to 0 for down servers). The loop is no longer possible with new
smooth algorithm, so preserving original weight is safe.
For edge case weights like { 5, 1, 1 } we now produce { a, a, b, a, c, a, a }
sequence instead of { c, b, a, a, a, a, a } produced previously.
Algorithm is as follows: on each peer selection we increase current_weight
of each eligible peer by its weight, select peer with greatest current_weight
and reduce its current_weight by total number of weight points distributed
among peers.
In case of { 5, 1, 1 } weights this gives the following sequence of
current_weight's:
a b c
0 0 0 (initial state)
5 1 1 (a selected)
-2 1 1
3 2 2 (a selected)
-4 2 2
1 3 3 (b selected)
1 -4 3
6 -3 4 (a selected)
-1 -3 4
4 -2 5 (c selected)
4 -2 -2
9 -1 -1 (a selected)
2 -1 -1
7 0 0 (a selected)
0 0 0
To preserve weight reduction in case of failures the effective_weight
variable was introduced, which usually matches peer's weight, but is
reduced temporarily on peer failures.
This change also fixes loop with backup servers and proxy_next_upstream
http_404 (ticket #47), and skipping alive upstreams in some cases if there
are multiple dead ones (ticket #64).
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).
If we already had CNAME in resolver node (i.e. rn->cnlen and rn->u.cname
set), and got additional response with A record, it resulted in rn->cnlen
set and rn->u.cname overwritten by rn->u.addr (or rn->u.addrs), causing
segmentation fault later in ngx_resolver_free_node() on an attempt to free
overwritten rn->u.cname. The opposite (i.e. CNAME got after A) might cause
similar problems as well.
In case of EMFILE/ENFILE returned from accept() we disable accept events,
and (in case of no accept mutex used) arm timer to re-enable them later.
With accept mutex we just drop it, and rely on normal accept mutex handling
to re-enable accept events once it's acquired again.
As we now handle errors in question, logging level was changed to "crit"
(instead of "alert" used for unknown errors).
Note: the code might call ngx_enable_accept_events() multiple times if
there are many listen sockets. The ngx_enable_accept_events() function was
modified to check if connection is already active (via c->read->active) and
skip it then, thus making multiple calls safe.
The following code resulted in incorrect escaping of uri and possible
segfault:
location / {
rewrite ^(.*) $1?c=$1;
return 200 "$uri";
}
If there were arguments in a rewrite's replacement string, and length was
actually calculated (due to duplicate captures as in the example above,
or variables present), the is_args flag was set and incorrectly copied
after length calculation. This resulted in escaping applied to the uri part
of the replacement, resulting in incorrect escaping. Additionally, buffer
was allocated without escaping expected, thus this also resulted in buffer
overrun and possible segfault.
Padding was incorrectly ignored on end request, empty stdout and stderr
fastcgi records. This resulted in protocol desynchronization if fastcgi
application used these records with padding for some reason.
Reported by Ilia Vinokurov.
Failing to do so results in problems if 400 or 414 requests are
redirected to fastcgi/scgi/uwsgi upstream, as well as after invalid
headers got from upstream. This was already fixed for proxy in r3478,
but fastcgi (the only affected protocol at that time) was missed.
Reported by Matthieu Tourne.
On internal redirects this happens via ngx_http_handler() call, which is
not called on named location redirect. As a result incorrect write handler
remained (if previously set) and this might cause incorrect behaviour (likely
request hang).
Patch by Yichun Zhang (agentzh).
If name passed for resolution was { 0, NULL } (e.g. as a result
of name server returning CNAME pointing to ".") pointer wrapped
to (void *) -1 resulting in segmentation fault on an attempt to
dereference it.
Reported by Lanshun Zhou.
The proxy module context may be NULL in case of filter finalization
(e.g. by image_filter) followed by an internal redirect. This needs
some better handling, but for now just check if ctx is still here.
The problem occured if first uri in try_files was shorter than request uri,
resulting in reserve being 0 and hence allocation skipped. The bug was
introduced in r4584 (1.1.19).
Instead of checking if there is events{} section present in configuration
in init_module handler we now do the same in init_conf handler. This
allows master process to detect incorrect configuration early and
reject it.
We now stop on IOV_MAX iovec entries only if we are going to add new one,
i.e. next buffer can't be coalesced into last iovec.
This also fixes incorrect checks for trailer creation on FreeBSD and
Mac OS X, header.nelts was checked instead of trailer.nelts.
The "complete" flag wasn't cleared on loop iteration start, resulting in
broken behaviour if there were more than IOV_MAX buffers and first
iteration was fully completed (and hence the "complete" flag was set
to 1).
Previous (incorrect) behaviour was to inherit ipv6 rules separately from
ipv4 ones. Now all rules are either inherited (if there are no rules
defined at current level) or not (if there are any rules defined).
Integer overflow is undefined behaviour in C and this indeed caused
problems on Solaris/SPARC (at least in some cases). Fix is to
subtract unsigned integers instead, and then cast result to a signed
one, which is implementation-defined behaviour and used to work.
Strictly speaking, we should compare (unsigned) result with the maximum
value of the corresponding signed integer type instead, this will be
defined behaviour. This will require much more changes though, and
considered to be overkill for now.
Such upstreams cause CPU hog later in the code as number of peers isn't
expected to be 0. Currently this may happen either if there are only backup
servers defined in an upstream block, or if server with ipv6 address used
in an upstream block.
Note that "ctxt->loadsubset = 1" previously used isn't really correct as
ctxt->loadsubset is a bitfield now. The use of xmlCtxtUseOptions() with
XML_PARSE_DTDLOAD is believed to be a better way to do the same thing.
Patch by Laurence Rowe.
POSIX doesn't require it to be defined, and Debian GNU/Hurd doesn't define
it. Note that if there is no MAX_PATH defined we have to use realpath()
with NULL argument and free() the result.
Most of the systems have it included due to namespace pollution, but
relying on this is a bad idea. Explicit include is required for at least
Debian GNU/Hurd.
The problem was introduced in 0.7.44 (r2589) during conversion to complex
values. Previously string.len included space for terminating NUL, but
with complex values it doesn't.
The bug in question is likely already fixed (though unfortunately we have
no information available as Apple's bugtracker isn't open), and the
workaround seems to be too pessimistic for modern versions of Safari
as well as other webkit-based browsers pretending to be Safari.
- Removed "hash" element from ngx_http_header_val_t which was always 1.
- Replaced NGX_HTTP_EXPIRES_* with ngx_http_expires_t enum type.
- Added prototype for ngx_http_add_header()
- Simplified ngx_http_set_last_modified().
This resulted in a disclosure of previously freed memory if upstream
server returned specially crafted response, potentially exposing
sensitive information.
Reported by Matthew Daley.
Embedded perl module assumes there is a space for terminating NUL character,
make sure to provide it in all situations by allocating one extra byte for
value buffer. Default ssi_value_length is reduced accordingly to
preserve 256 byte allocations.
While here, fixed another one byte value buffer overrun possible in
ssi_quoted_symbol_state.
Reported by Matthew Daley.
It wasn't enforced for a long time, and there are reports that people
use up to 100 simultaneous subrequests now. As this is a safety limit
to prevent loops, it's raised accordingly.
ZFS reports incorrect st_blocks until file settles on disk, and this
may take a while (i.e. just after creation of a file the st_blocks value
is incorrect). As a workaround we now use st_blocks only if
st_blocks * 512 > st_size, this should fix ZFS problems while still
preserving accuracy for other filesystems.
The problem had appeared in r3900 (1.0.1).
Previous code incorrectly assumed that nodes with identical keys are linked
together. This might not be true after tree rebalance.
Patch by Lanshun Zhou.
The cycle->new_log.file may not be set before config parsing finished if
there are no error_log directive defined at global level. Fix is to
copy it after config parsing.
Patch by Roman Arutyunyan.
With previous code raw buffer might be lost if p->input_filter() was called
on a buffer without any data and used ngx_event_pipe_add_free_buf() to
return it to the free list. This eventually might cause "all buffers busy"
problem, resulting in segmentation fault due to null pointer dereference in
ngx_event_pipe_write_chain_to_temp_file().
In ngx_event_pipe_add_free_buf() the buffer was added to the list start
due to pos == last, and then "p->free_raw_bufs = cl->next" in
ngx_event_pipe_read_upstream() dropped both chain links to the buffer
from the p->free_raw_bufs list.
Fix is to move "p->free_raw_bufs = cl->next" before calling the
p->input_filter().
the last path component if "if_not_owner" parameter is used.
To prevent race condition we have to open a file before checking its owner and
there's no way to change access flags for already opened file descriptor, so
we disable symlinks for the last path component at all if flags allow creating
or truncating the file.
Solaris has AT_FDCWD defined to unsigned value, and comparison of a file
descriptor with it causes warnings in modern versions of gcc. Explicitly
cast AT_FDCWD to ngx_fd_t to resolve these warnings.
To completely disable symlinks (disable_symlinks on)
we use openat(O_NOFOLLOW) for each path component
to avoid races.
To allow symlinks with the same owner (disable_symlinks if_not_owner),
use openat() (followed by fstat()) and fstatat(AT_SYMLINK_NOFOLLOW),
and then compare uids between fstat() and fstatat().
As there is a race between openat() and fstatat() we don't
know if openat() in fact opened symlink or not. Therefore,
we have to compare uids even if fstatat() reports the opened
component isn't a symlink (as we don't know whether it was
symlink during openat() or not).
Default value is off, i.e. symlinks are allowed.
