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Latest commit 96f64a0 @azat azat evdns: name_parse(): fix remote stack overread
  "the name_parse() function in libevent's DNS code is vulnerable to a buffer overread.

   971         if (cp != name_out) {
   972             if (cp + 1 >= end) return -1;
   973             *cp++ = '.';
   974         }
   975         if (cp + label_len >= end) return -1;
   976         memcpy(cp, packet + j, label_len);
   977         cp += label_len;
   978         j += label_len;
   No check is made against length before the memcpy occurs.

   This was found through the Tor bug bounty program and the discovery should be credited to 'Guido Vranken'."

Reproducer for gdb (
  set $PROT_NONE=0x0
  set $PROT_READ=0x1
  set $PROT_WRITE=0x2
  set $MAP_ANONYMOUS=0x20
  set $MAP_SHARED=0x01
  set $MAP_FIXED=0x10
  set $MAP_32BIT=0x40


  set $length=202
  # overread
  set $length=2
  # allocate with mmap to have a seg fault on page boundary
  set $l=(1<<20)*2
  set $packet=(char *)$1+$l-$length
  # hack the packet
  set $packet[0]=63
  set $packet[1]='/'

  p malloc(sizeof(int))
  set $idx=(int *)$2
  set $idx[0]=0
  set $name_out_len=202

  p malloc($name_out_len)
  set $name_out=$3

  # have WRITE only mapping to fail on read
  set $end=$1+$l
  p (void *)mmap($end, 1<<12, $PROT_NONE, $MAP_ANONYMOUS|$MAP_SHARED|$MAP_FIXED|$MAP_32BIT, -1, 0)
  set $m=$4

  p name_parse($packet, $length, $idx, $name_out, $name_out_len)
  x/2s (char *)$name_out

Before this patch:
$ gdb -ex 'source gdb' dns-example
$1 = 1073741824
$2 = (void *) 0x633010
$3 = (void *) 0x633030
$4 = (void *) 0x40200000

Program received signal SIGSEGV, Segmentation fault.
__memcpy_sse2_unaligned () at memcpy-sse2-unaligned.S:33

After this patch:
$ gdb -ex 'source gdb' dns-example
$1 = 1073741824
$2 = (void *) 0x633010
$3 = (void *) 0x633030
$4 = (void *) 0x40200000
$5 = -1
0x633030:       "/"
0x633032:       ""
(gdb) p $m
$6 = (void *) 0x40200000
(gdb) p $1
$7 = 1073741824
(gdb) p/x $1
$8 = 0x40000000
(gdb) quit

P.S. plus drop one condition duplicate.

Fixes: #317
Failed to load latest commit information.
WIN32-Code Increment version to 2.1.5-beta
cmake More cmake updates, lot's of missing definitions
compat/sys Fix all identifiers with names beginning with underscore.
include visibility: align it to make it more readable
m4 Merge remote-tracking branch 'origin/patches-2.0'
sample http-connect: make it win32 compilable
test Add missing return statement to del_wait_thread so libevent can build.
.gitignore Ignore more configure stuff (configure.lineno)
.travis.yml travis: add builds without debug mode into matrix
CMakeLists.txt cmake: fix building dns-example under win32 (missing getopt)
ChangeLog Update changelog
ChangeLog-1.4 Try to finalize changelog situation for 2.1.1-alpha
ChangeLog-2.0 Update ChangeLog-2.0
Doxyfile Fix doxygen to use new macro conventions
LICENSE Implement fast/precise monotonic clocks on Windows Increment version to 2.1.5-beta
Makefile.nmake Revert "The Windows socket type is defined as SOCKET." Update
appveyor.yml Use autotools for appveyor until cmake is fixed.
arc4random.c Merge remote-tracking branch 'origin/patches-2.0' Prefer autoreconf -ivf to manual
buffer.c Don't use BSD u_* types.
buffer_iocp.c Have all visible internal function names end with an underscore.
bufferevent-internal.h be: introduce bufferevent_generic_adj_existing_timeouts_()
bufferevent.c be: introduce bufferevent_generic_adj_existing_timeouts_()
bufferevent_async.c be async: avoid double close()
bufferevent_filter.c Call underlying bev ctrl SET_FD on filtered bufferevents
bufferevent_openssl.c be_openssl: don't call do_write() directly from outbuf_cb
bufferevent_pair.c Fix lock leak in be_pair_flush() if flush type is BEV_NORMAL
bufferevent_ratelim.c Pass and return const for bufferevent_get_token_bucket_cfg
bufferevent_sock.c be_sock: bufferevent_socket_connect_hostname(): make it thread-safe
changelist-internal.h Implemented EV_CLOSED event for epoll backend (EPOLLRDHUP). autotools: fix getservbyname() detection
defer-internal.h fix the return value of event_deferred_cb_schedule_
devpoll.c Have all visible internal function names end with an underscore.
epoll.c epoll: introduce PRINT_CHANGES() macro to avoid copy-pasting
epoll_sub.c Merge remote-tracking branch 'origin/patches-2.0'
epolltable-internal.h Split epoll lookup table into a separate header file
evbuffer-internal.h Fix CVE-2014-6272 in Libevent 2.1
evconfig-private.h.cmake Generate a dummy evconfig-private.h so things build properly. Clean up lingering _identifiers.
evdns.3 improved nroff mdoc for the man page
evdns.c evdns: name_parse(): fix remote stack overread
event-config.h.cmake cmake: don't define EVENT__NEED_DLLIMPORT always (fixes VS2013 static…
event-internal.h Add a prototype for event_disable_debug_mode()
event.3 Don't use BSD u_* types.
event.c event_reinit: make signals works after fork() without evsig_add()
event_iocp.c Merge remote-tracking branch 'origin/patches-2.0' Merge remote-tracking branch 'origin/patches-2.0'
event_tagging.c Include <sys/ioctl.h>, <sys/resource.h> and <sys/wait.h> optionally.
evmap-internal.h Have all visible internal function names end with an underscore.
evmap.c Implemented EV_CLOSED event for epoll backend (EPOLLRDHUP).
evport.c Have all visible internal function names end with an underscore.
evrpc-internal.h Add an include to evrpc-internal to fix openbsd compilation warning
evrpc.c Fix even more coverity warnings.
evsignal-internal.h Add a new libevent_global_shutdown() to free all globals before exiting.
evthread-internal.h Fix "function declaration isn’t a prototype"
evthread.c evthread: fix evthread_setup_global_lock_() for debug-lock with a rea…
evthread_pthread.c Clean up lingering _identifiers.
evthread_win32.c Merge remote-tracking branch 'origin/patches-2.0'
evutil.c evutil_parse_sockaddr_port(): fix buffer overflow
evutil_rand.c Merge remote-tracking branch 'origin/patches-2.0'
evutil_time.c Implement new/free for struct evutil_monotonic_timer and export monot…
ht-internal.h ht-internal: don't reset hth_table_length explicitly in name_##HT_CLEAR
http-internal.h Don't use BSD u_* types.
http.c http: avoid epoll_ctl() on already closed fd (triggers by http/chunk_…
iocp-internal.h Have all visible internal function names end with an underscore.
ipv6-internal.h Convert include-guard macro convention to avoid reserved identifiers
kqueue-internal.h Replace pipe-based notification with EVFILT_USER where possible
kqueue.c Assume that ke_udata is an integer type on CloudABI. Change use of AC_CHECK_LIB to AC_SEARCH_LIBS. Use correct openssl libs and includes in pkgconfig file Add pkgconfig files for libevent_{openssl,pthreads}
listener.c Fix potential fd leak in listener_read_cb()
log-internal.h Actually use the log facility for reporting evdns problems.
log.c Actually use the log facility for reporting evdns problems.
make-event-config.sed Generate event-config.h with a single sed script Implemented EV_CLOSED event for epoll backend (EPOLLRDHUP).
minheap-internal.h Remove an unreachable return statement in minheap-internal.h
mm-internal.h Convert include-guard macro convention to avoid reserved identifiers
poll.c Split out time-related prototypes into time-internal.h
ratelim-internal.h Have all visible internal function names end with an underscore.
select.c Tweak the new evutil_weakrand_() code
signal.c Merge remote-tracking branch 'github/20_win64_compilation' into 21_wi…
strlcpy-internal.h Fix all identifiers with names beginning with underscore.
strlcpy.c Fix all identifiers with names beginning with underscore.
time-internal.h Implement new/free for struct evutil_monotonic_timer and export monot…
util-internal.h util: make @sa const for evutil_socket_connect_()
whatsnew-2.0.txt "buffer" spelling
whatsnew-2.1.txt Add new APIs to whatsnew-2.1
win32select.c Don't use BSD u_* types.

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 $ ./configure
 $ make
 $ make verify   # (optional)
 $ sudo make install

Cmake (General)

The following Libevent specific Cmake variables ar as follows (the values being the default).

# Installation directory for executables

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## Installation directory for header files

## Installation directory for libraries

## Define if libevent should be built with shared libraries instead of archives

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More variables can be found by running cmake -LAH <sourcedir_path>

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 $ cmake -G "Visual Studio 10" ..   # Or whatever generator you want to use cmake --help for a list.
 $ start libevent.sln

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 $ make verify

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 $ CFLAGS=-DUSE_DEBUG ./configure [...]

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