view auto/os/darwin @ 6359:dac6eda40475 stable-1.8

Resolver: fixed use-after-free memory accesses with CNAME. When several requests were waiting for a response, then after getting a CNAME response only the last request's context had the name updated. Contexts of other requests had the wrong name. This name was used by ngx_resolve_name_done() to find the node to remove the request context from. When the name was wrong, the request could not be properly cancelled, its context was freed but stayed linked to the node's waiting list. This happened e.g. when the first request was aborted or timed out before the resolving completed. When it completed, this triggered a use-after-free memory access by calling ctx->handler of already freed request context. The bug manifests itself by "could not cancel <name> resolving" alerts in error_log. When a request was responded with a CNAME, the request context kept the pointer to the original node's rn->u.cname. If the original node expired before the resolving timed out or completed with an error, this would trigger a use-after-free memory access via ctx->name in ctx->handler(). The fix is to keep ctx->name unmodified. The name from context is no longer used by ngx_resolve_name_done(). Instead, we now keep the pointer to resolver node to which this request is linked. Keeping the original name intact also improves logging.
author Roman Arutyunyan <arut@nginx.com>
date Tue, 26 Jan 2016 16:46:59 +0300
parents 79b473d5381d
children 85dea406e18f
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_DARWIN . auto/have_headers

CORE_INCS="$UNIX_INCS"
CORE_DEPS="$UNIX_DEPS $DARWIN_DEPS"
CORE_SRCS="$UNIX_SRCS $DARWIN_SRCS"



ngx_spacer='
'

# kqueue

echo " + kqueue found"
have=NGX_HAVE_KQUEUE . auto/have
have=NGX_HAVE_CLEAR_EVENT . auto/have
EVENT_MODULES="$EVENT_MODULES $KQUEUE_MODULE"
CORE_SRCS="$CORE_SRCS $KQUEUE_SRCS"
EVENT_FOUND=YES
NGX_KQUEUE_CHECKED=YES

ngx_feature="kqueue's EVFILT_TIMER"
ngx_feature_name="NGX_HAVE_TIMER_EVENT"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/event.h>
                  #include <sys/time.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int      kq;
                  struct kevent    kev;
                  struct timespec  ts;

                  if ((kq = kqueue()) == -1) return 1;

                  kev.ident = 0;
                  kev.filter = EVFILT_TIMER;
                  kev.flags = EV_ADD|EV_ENABLE;
                  kev.fflags = 0;
                  kev.data = 1000;
                  kev.udata = 0;

                  ts.tv_sec = 0;
                  ts.tv_nsec = 0;

                  if (kevent(kq, &kev, 1, &kev, 1, &ts) == -1) return 1;

                  if (kev.flags & EV_ERROR) return 1;"

. auto/feature


ngx_feature="Darwin 64-bit kqueue millisecond timeout bug"
ngx_feature_name=NGX_DARWIN_KEVENT_BUG
ngx_feature_run=bug
ngx_feature_incs="#include <sys/event.h>
                  #include <sys/time.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int  kq;
                  struct kevent    kev;
                  struct timespec  ts;
                  struct timeval   tv, tv0;

                  kq = kqueue();

                  ts.tv_sec = 0;
                  ts.tv_nsec = 999000000;

                  gettimeofday(&tv, 0);
                  kevent(kq, NULL, 0, &kev, 1, &ts);
                  gettimeofday(&tv0, 0);
                  timersub(&tv0, &tv, &tv);

                  if (tv.tv_sec * 1000000 + tv.tv_usec < 900000) return 1;"

. auto/feature


# sendfile()

CC_AUX_FLAGS="$CC_AUX_FLAGS"
ngx_feature="sendfile()"
ngx_feature_name="NGX_HAVE_SENDFILE"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/types.h>
                  #include <sys/socket.h>
                  #include <sys/uio.h>
                  #include <sys/errno.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int s = 0, fd = 1;
                  off_t n; off_t off = 0;
                  n = sendfile(s, fd, off, &n, NULL, 0);
                  if (n == -1 && errno == ENOSYS) return 1"
. auto/feature

if [ $ngx_found = yes ]; then
    CORE_SRCS="$CORE_SRCS $DARWIN_SENDFILE_SRCS"
fi


ngx_feature="atomic(3)"
ngx_feature_name=NGX_DARWIN_ATOMIC
ngx_feature_run=no
ngx_feature_incs="#include <libkern/OSAtomic.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int32_t  lock, n;
                  n = OSAtomicCompareAndSwap32Barrier(0, 1, &lock)"
. auto/feature