WIP: http: test: work-around ASAN false positive (!4716) · Merge requests · VideoLAN / VLC

Thomas Guillem requested to merge tguillem/vlc:asan-http-false into master Dec 22, 2023
On top on !4715 (closed), only the last commit should be reviewed.
Reproduced with Debian clang version 17.0.6

Not systematic. To reproduce it, run the test in loop
$ while ./modules/h2conn_test; do echo ""; done`

While stressing the machine a little bit:
$ stress --cpu 32 -i 1000

==892210==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fae954fdb90 at pc 0x55da59444573 bp 0x7fae954fdb70 sp 0x7fae954fd340
WRITE of size 24 at 0x7fae954fdb90 thread T4 (vlc-h2-recv)
    #0 0x55da59444572 in sigaltstack (/home/tom/work/git/vlc/build-asan/modules/.libs/h2conn_test+0xa4572) (BuildId: 8ead1e4d94475932abd3d192f0c9c782a2470ea0)
    #1 0x55da5947188f in __asan::PlatformUnpoisonStacks() (/home/tom/work/git/vlc/build-asan/modules/.libs/h2conn_test+0xd188f) (BuildId: 8ead1e4d94475932abd3d192f0c9c782a2470ea0)
    #2 0x55da594778b7 in __asan_handle_no_return (/home/tom/work/git/vlc/build-asan/modules/.libs/h2conn_test+0xd78b7) (BuildId: 8ead1e4d94475932abd3d192f0c9c782a2470ea0)
    #3 0x55da594b6d33 in vlc_h2_recv_thread /home/tom/work/git/vlc/build-asan/modules/../../modules/access/http/h2conn.c:804:5
    #4 0x55da5946b70a in asan_thread_start(void*) asan_interceptors.cpp.o
    #5 0x7fae98877043  (/lib/x86_64-linux-gnu/libc.so.6+0x89043) (BuildId: 51657f818beb1ae70372216a99b7412b8a100a20)
    #6 0x7fae988f761b  (/lib/x86_64-linux-gnu/libc.so.6+0x10961b) (BuildId: 51657f818beb1ae70372216a99b7412b8a100a20)

Address 0x7fae954fdb90 is located in stack of thread T4 (vlc-h2-recv) at offset 208 in frame
    #0 0x55da594b897f in vlc_h2_frame_recv /home/tom/work/git/vlc/build-asan/modules/../../modules/access/http/h2conn.c:754

  This frame has 2 object(s):
    [32, 41) 'header' (line 755)
    [64, 168) '__cancel_buf' (line 773) <== Memory access at offset 208 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
      (longjmp and C++ exceptions *are* supported)
Thread T4 (vlc-h2-recv) created by T0 here:
    #0 0x55da5945349d in pthread_create (/home/tom/work/git/vlc/build-asan/modules/.libs/h2conn_test+0xb349d) (BuildId: 8ead1e4d94475932abd3d192f0c9c782a2470ea0)
    #1 0x7fae98c2af4c in vlc_clone_attr /home/tom/work/git/vlc/build-asan/src/../../src/posix/thread.c:180:11
    #2 0x7fae98c2af4c in vlc_clone /home/tom/work/git/vlc/build-asan/src/../../src/posix/thread.c:191:12
    #3 0x55da594b68c2 in vlc_h2_conn_create /home/tom/work/git/vlc/build-asan/modules/../../modules/access/http/h2conn.c:897:9
    #4 0x55da594ab69c in conn_create /home/tom/work/git/vlc/build-asan/modules/../../modules/access/http/h2conn_test.c:106:12
    #5 0x55da594aa472 in main /home/tom/work/git/vlc/build-asan/modules/../../modules/access/http/h2conn_test.c:172:5
    #6 0x7fae988151c9  (/lib/x86_64-linux-gnu/libc.so.6+0x271c9) (BuildId: 51657f818beb1ae70372216a99b7412b8a100a20)

SUMMARY: AddressSanitizer: stack-buffer-overflow (/home/tom/work/git/vlc/build-asan/modules/.libs/h2conn_test+0xa4572) (BuildId: 8ead1e4d94475932abd3d192f0c9c782a2470ea0) in sigaltstack
WIP: http: test: work-around ASAN false positive

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