Specially crafted wav file causing a buffer overflow in vlc

[Gustavo]

Hi,

We found a buffer overflow in the parsing and processing of wav files in VLC (version 2.1.6-0). It was tested in Ubuntu 14.04 (x86_64), but it will probably affects other versions as well. Find attached a test case to reproduce it. Here you can see the gdb stack trace:

__memcpy_sse2_unaligned () at ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:116
116 ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: No existe el archivo o el directorio.
(gdb) bt
#0 __memcpy_sse2_unaligned () at ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:116
#1 0x00007ffff71436e9 in memcpy (__len=4290773038, __src=<optimized out>, __dest=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:51
#2 AStreamPeekStream (s=<optimized out>, pp_peek=0x7fffea824988, i_read=4294967276) at input/stream.c:1115
#3 0x00007fffdebb42b3 in ChunkFind (p_demux=p_demux@entry=0x7fffd4c01828, fcc=fcc@entry=0x7fffdebb576b "fmt ", pi_size=pi_size@entry=0x7fffea824a3c)
    at wav.c:522
#4 0x00007fffdebb4761 in Open (p_this=0x7fffd4c01828) at wav.c:166
#5 0x00007ffff716d178 in module_load (obj=obj@entry=0x7fffd4c01828, m=m@entry=0x7b92b0, init=init@entry=0x7ffff716d0d0 <generic_start>,
    args=args@entry=0x7fffea824b50) at modules/modules.c:185
#6 0x00007ffff716d72e in vlc_module_load (obj=obj@entry=0x7fffd4c01828, capability=capability@entry=0x7ffff71a4059 "demux", name=0x7ffff71a43bb "",
    name@entry=0x7fffd4c018e0 "", strict=<optimized out>, probe=probe@entry=0x7ffff716d0d0 <generic_start>) at modules/modules.c:277
#7 0x00007ffff716dc04 in module_need (obj=obj@entry=0x7fffd4c01828, cap=cap@entry=0x7ffff71a4059 "demux", name=name@entry=0x7fffd4c018e0 "",
    strict=<optimized out>) at modules/modules.c:366
#8 0x00007ffff712cfbe in demux_New (p_obj=p_obj@entry=0x7fffd00009b8, p_parent_input=p_parent_input@entry=0x7fffd00009b8,
    psz_access=<optimized out>, psz_demux=0x7ffff71b9ca5 "", psz_location=<optimized out>, s=<optimized out>, out=0x7fffd4000aa0, b_quick=false)
    at input/demux.c:188
#9 0x00007ffff7139d5d in InputSourceInit (p_input=p_input@entry=0x7fffd00009b8, in=<optimized out>, psz_mrl=<optimized out>,
    psz_forced_demux=psz_forced_demux@entry=0x0, b_in_can_fail=b_in_can_fail@entry=false) at input/input.c:2535
#10 0x00007ffff713ab6b in Init (p_input=p_input@entry=0x7fffd00009b8) at input/input.c:1225
#11 0x00007ffff713e0e6 in Run (obj=0x7fffd00009b8) at input/input.c:521
#12 0x00007ffff79a9182 in start_thread (arg=0x7fffea825700) at pthread_create.c:312
#13 0x00007ffff74d247d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

It is evident that the memcpy operation has an abnormally large size parameter (4290773038). It shouldn't be difficult to exploit this bug to obtain arbitrary memory execution overwriting some function pointer.

Regards,
Gustavo.

[Marc Deslauriers (mdeslaur)]

Thanks for discovering this.
Please notify the upstream vlc developers, and link the bug you've reported with this one.

Thanks!

[Gustavo (gustavo-grieco)]

----- Original Message -----
> Thanks for discovering this.
> Please notify the upstream vlc developers, and link the bug you've reported
> with this one.

I just tested it with a recent git version of vlc (3.0.0-git) and it wasn't crashing or anything (i used valgrind).

>
> Thanks!
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1533633
>
> Title:
> Specially crafted wav file causing a buffer overflow in vlc
>
> Status in vlc package in Ubuntu:
> New
>
> Bug description:
> Hi,
>
> We found a buffer overflow in the parsing and processing of wav files
> in VLC (version 2.1.6-0). It was tested in Ubuntu 14.04 (x86_64), but
> it will probably affects other versions as well. Find attached a test
> case to reproduce it. Here you can see the gdb stack trace:
>
> __memcpy_sse2_unaligned () at
> ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:116
> 116 ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: No existe el
> archivo o el directorio.
> (gdb) bt
> #0 __memcpy_sse2_unaligned () at
> ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:116
> #1 0x00007ffff71436e9 in memcpy (__len=4290773038, __src=<optimized out>,
> __dest=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:51
> #2 AStreamPeekStream (s=<optimized out>, pp_peek=0x7fffea824988,
> i_read=4294967276) at input/stream.c:1115
> #3 0x00007fffdebb42b3 in ChunkFind (p_demux=p_demux@entry=0x7fffd4c01828,
> fcc=fcc@entry=0x7fffdebb576b "fmt ", pi_size=pi_size@entry=0x7fffea824a3c)
> at wav.c:522
> #4 0x00007fffdebb4761 in Open (p_this=0x7fffd4c01828) at wav.c:166
> #5 0x00007ffff716d178 in module_load (obj=obj@entry=0x7fffd4c01828,
> m=m@entry=0x7b92b0, init=init@entry=0x7ffff716d0d0 <generic_start>,
> args=args@entry=0x7fffea824b50) at modules/modules.c:185
> #6 0x00007ffff716d72e in vlc_module_load (obj=obj@entry=0x7fffd4c01828,
> capability=capability@entry=0x7ffff71a4059 "demux", name=0x7ffff71a43bb
> "",
> name@entry=0x7fffd4c018e0 "", strict=<optimized out>,
> probe=probe@entry=0x7ffff716d0d0 <generic_start>) at
> modules/modules.c:277
> #7 0x00007ffff716dc04 in module_need (obj=obj@entry=0x7fffd4c01828,
> cap=cap@entry=0x7ffff71a4059 "demux", name=name@entry=0x7fffd4c018e0 "",
> strict=<optimized out>) at modules/modules.c:366
> #8 0x00007ffff712cfbe in demux_New (p_obj=p_obj@entry=0x7fffd00009b8,
> p_parent_input=p_parent_input@entry=0x7fffd00009b8,
> psz_access=<optimized out>, psz_demux=0x7ffff71b9ca5 "",
> psz_location=<optimized out>, s=<optimized out>, out=0x7fffd4000aa0,
> b_quick=false)
> at input/demux.c:188
> #9 0x00007ffff7139d5d in InputSourceInit
> (p_input=p_input@entry=0x7fffd00009b8, in=<optimized out>,
> psz_mrl=<optimized out>,
> psz_forced_demux=psz_forced_demux@entry=0x0,
> b_in_can_fail=b_in_can_fail@entry=false) at input/input.c:2535
> #10 0x00007ffff713ab6b in Init (p_input=p_input@entry=0x7fffd00009b8) at
> input/input.c:1225
> #11 0x00007ffff713e0e6 in Run (obj=0x7fffd00009b8) at input/input.c:521
> #12 ...

[Gustavo (gustavo-grieco)]

Hi!.

Any updates on this issue?

[Marc Deslauriers (mdeslaur)]

vlc is in universe, which means it's community maintained.

If you would like to see an update to the vlc package in Ubuntu, you need to submit a debdiff to fix this issue. When a debdiff is available, members of the security team will review it and publish the package. See the following link for more information: https://wiki.ubuntu.com/SecurityTeam/UpdateProcedures

[Gustavo (gustavo-grieco)]

I see. Unfortunately, i have no experience in the vlc source code. In any case, is it possible to make this issue public so someone else can fix it ? (probably using oss-security)

[Marc Deslauriers (mdeslaur)]

Definitely, please do. Thanks!

[Sebastian Ramacher (s-ramacher)]

Fixed since 321fa90d585b9ebcb317cf6e575edf2bb952b687 in the 2.2 branch, which was included in 2.2.0-1. All 2.1.x release are affected though.

[Gustavo (gustavo-grieco)]

Any chance to this fix in trusty?