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Anders Bakken 406506ca92 curl_multi_remove_handle: fix a double-free
In short the easy handle needs to be disconnected from its connection at
this point since the connection still is serving other easy handles.

In our app we can reliably reproduce a crash in our http2 stress test
that is fixed by this change. I can't easily reproduce the same test in
a small example.

This is the gdb/asan output:

==11785==ERROR: AddressSanitizer: heap-use-after-free on address 0xe9f4fb80 at pc 0x09f41f19 bp 0xf27be688 sp 0xf27be67c
READ of size 4 at 0xe9f4fb80 thread T13 (RESOURCE_HTTP)
    #0 0x9f41f18 in curl_multi_remove_handle /path/to/source/3rdparty/curl/lib/multi.c:666

0xe9f4fb80 is located 0 bytes inside of 1128-byte region [0xe9f4fb80,0xe9f4ffe8)
freed by thread T13 (RESOURCE_HTTP) here:
    #0 0xf7b1b5c2 in __interceptor_free /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_malloc_linux.cc:45
    #1 0x9f7862d in conn_free /path/to/source/3rdparty/curl/lib/url.c:2808
    #2 0x9f78c6a in Curl_disconnect /path/to/source/3rdparty/curl/lib/url.c:2876
    #3 0x9f41b09 in multi_done /path/to/source/3rdparty/curl/lib/multi.c:615
    #4 0x9f48017 in multi_runsingle /path/to/source/3rdparty/curl/lib/multi.c:1896
    #5 0x9f490f1 in curl_multi_perform /path/to/source/3rdparty/curl/lib/multi.c:2123
    #6 0x9c4443c in perform /path/to/source/src/net/resourcemanager/ResourceManagerCurlThread.cpp:854
    #7 0x9c445e0 in ...
    #8 0x9c4cf1d in ...
    #9 0xa2be6b5 in ...
    #10 0xf7aa5780 in asan_thread_start /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_interceptors.cc:226
    #11 0xf4d3a16d in __clone (/lib/i386-linux-gnu/libc.so.6+0xe716d)

previously allocated by thread T13 (RESOURCE_HTTP) here:
    #0 0xf7b1ba27 in __interceptor_calloc /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_malloc_linux.cc:70
    #1 0x9f7dfa6 in allocate_conn /path/to/source/3rdparty/curl/lib/url.c:3904
    #2 0x9f88ca0 in create_conn /path/to/source/3rdparty/curl/lib/url.c:5797
    #3 0x9f8c928 in Curl_connect /path/to/source/3rdparty/curl/lib/url.c:6438
    #4 0x9f45a8c in multi_runsingle /path/to/source/3rdparty/curl/lib/multi.c:1411
    #5 0x9f490f1 in curl_multi_perform /path/to/source/3rdparty/curl/lib/multi.c:2123
    #6 0x9c4443c in perform /path/to/source/src/net/resourcemanager/ResourceManagerCurlThread.cpp:854
    #7 0x9c445e0 in ...
    #8 0x9c4cf1d in ...
    #9 0xa2be6b5 in ...
    #10 0xf7aa5780 in asan_thread_start /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_interceptors.cc:226
    #11 0xf4d3a16d in __clone (/lib/i386-linux-gnu/libc.so.6+0xe716d)

SUMMARY: AddressSanitizer: heap-use-after-free /path/to/source/3rdparty/curl/lib/multi.c:666 in curl_multi_remove_handle
Shadow bytes around the buggy address:
  0x3d3e9f20: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9f30: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9f40: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9f50: fd fd fd fd fd fd fd fd fd fd fd fd fd fa fa fa
  0x3d3e9f60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x3d3e9f70:[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9f80: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9f90: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9fa0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9fb0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x3d3e9fc0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==11785==ABORTING

Thread 14 "RESOURCE_HTTP" received signal SIGABRT, Aborted.
[Switching to Thread 0xf27bfb40 (LWP 12324)]
0xf7fd8be9 in __kernel_vsyscall ()
 (gdb) bt
 #0  0xf7fd8be9 in __kernel_vsyscall ()
 #1  0xf4c7ee89 in __GI_raise (sig=6) at ../sysdeps/unix/sysv/linux/raise.c:54
 #2  0xf4c803e7 in __GI_abort () at abort.c:89
 #3  0xf7b2ef2e in __sanitizer::Abort () at /opt/toolchain/src/gcc-6.2.0/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cc:122
 #4  0xf7b262fa in __sanitizer::Die () at /opt/toolchain/src/gcc-6.2.0/libsanitizer/sanitizer_common/sanitizer_common.cc:145
 #5  0xf7b21ab3 in __asan::ScopedInErrorReport::~ScopedInErrorReport (this=0xf27be171, __in_chrg=<optimized out>) at /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_report.cc:689
 #6  0xf7b214a5 in __asan::ReportGenericError (pc=166993689, bp=4068206216, sp=4068206204, addr=3925146496, is_write=false, access_size=4, exp=0, fatal=true) at /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_report.cc:1074
 #7  0xf7b21fce in __asan::__asan_report_load4 (addr=3925146496) at /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_rtl.cc:129
 #8  0x09f41f19 in curl_multi_remove_handle (multi=0xf3406080, data=0xde582400) at /path/to/source3rdparty/curl/lib/multi.c:666
 #9  0x09f6b277 in Curl_close (data=0xde582400) at /path/to/source3rdparty/curl/lib/url.c:415
 #10 0x09f3354e in curl_easy_cleanup (data=0xde582400) at /path/to/source3rdparty/curl/lib/easy.c:860
 #11 0x09c6de3f in ...
 #12 0x09c378c5 in ...
 #13 0x09c48133 in ...
 #14 0x09c4d092 in ...
 #15 0x0a2be6b6 in ...
 #16 0xf7aa5781 in asan_thread_start (arg=0xf2d22938) at /opt/toolchain/src/gcc-6.2.0/libsanitizer/asan/asan_interceptors.cc:226
 #17 0xf5de52b5 in start_thread (arg=0xf27bfb40) at pthread_create.c:333
 #18 0xf4d3a16e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:114

Fixes #1083
2016-10-22 15:50:22 +02:00
.github docs: Fix link to CONTRIBUTE in Github contribution guidelines (#994) 2016-09-06 10:35:00 +02:00
CMake cmake: add nghttp2 support 2016-10-10 19:47:31 +02:00
docs INSTALL: converted to markdown => INSTALL.md 2016-10-21 15:57:29 +02:00
include New libcurl option to keep sending on error 2016-09-22 22:22:31 +02:00
lib curl_multi_remove_handle: fix a double-free 2016-10-22 15:50:22 +02:00
m4 configure/CURL_CHECK_FUNC_POLL: disable poll completely on mac 2016-10-18 23:03:27 +02:00
packages New libcurl option to keep sending on error 2016-09-22 22:22:31 +02:00
projects README: Corrected the supported Visual Studio versions 2016-08-31 11:34:50 +01:00
scripts contrithanks.sh: exclude existing names case insensitively 2016-05-23 10:07:48 +02:00
src s/cURL/curl 2016-10-18 13:59:54 +02:00
tests testcurl.1: fix the URL to the autobuild summary 2016-10-22 15:15:34 +02:00
winbuild winbuild: Allow changing C compiler via environment variable CC (#952) 2016-08-09 21:27:36 +02:00
.dir-locals.el Add .dir-locals and set c-basic-offset to 2. 2015-12-23 10:16:14 +01:00
.gitattributes Tell git to not convert configure-related files. 2012-07-17 20:35:23 +02:00
.gitignore build: Install zsh completion 2015-11-24 22:22:01 +01:00
.travis.yml travis: removed option to rebuild autotool from source 2016-08-03 13:25:32 +02:00
CHANGES URLs: change all http:// URLs to https:// 2016-02-03 00:19:02 +01:00
CHANGES.0 URLs: change more http to https 2016-02-04 18:46:54 -05:00
CMakeLists.txt s/cURL/curl 2016-10-18 13:59:54 +02:00
COPYING COPYING: clarify that Daniel is not the sole author 2016-02-06 18:40:27 +01:00
CTestConfig.cmake ENH: move dashboard location 2009-07-15 19:40:46 +00:00
GIT-INFO GIT-INFO: remove the Mac 10.1-specific details 2016-10-10 10:29:19 +02:00
MacOSX-Framework MacOSX-Framework: sdk regex fix for sdk 10.10 and later 2015-10-25 12:35:49 +01:00
Makefile.am dist: add missing cmake modules to the tarball 2016-10-11 22:57:36 -04:00
Makefile.dist URLs: change all http:// URLs to https:// 2016-02-03 00:19:02 +01:00
README URLs: follow GitHub project rename (also Travis CI) 2016-02-04 23:01:38 +01:00
README.md README.md: add our CII Best Practices badge 2016-08-15 11:15:01 +02:00
RELEASE-NOTES RELEASE-NOTES: synced with f36f8c1455 2016-10-18 17:17:54 +02:00
acinclude.m4 configure: Check for other variants of the -m*os*-version-min flags 2016-10-20 12:40:17 +02:00
appveyor.yml Appveyor: Updates for options - CURL_STATICLIB/BUILD_TESTING 2016-07-01 09:53:22 +02:00
buildconf URLs: change all http:// URLs to https:// 2016-02-03 00:19:02 +01:00
buildconf.bat dist: ship buildconf.bat too 2016-02-12 16:45:25 +01:00
configure.ac configure: set min version flags for builds on mac 2016-10-20 10:17:04 +02:00
curl-config.in URLs: change all http:// URLs to https:// 2016-02-03 00:19:02 +01:00
libcurl.pc.in URLs: change all http:// URLs to https:// 2016-02-03 00:19:02 +01:00
maketgz maketgz: make it support "only" generating version info 2016-10-17 09:29:46 +02:00

README.md

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