CVE-2021-44922: Null Pointer Dereference in BD_CheckSFTimeOffset() · Issue #1969 · gpac/gpac

Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

• I looked for a similar issue and couldn’t find any.
• I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
• I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line …). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

A null pointer dereference was discovered in BD_CheckSFTimeOffset(). The vulnerability causes a segmentation fault and application crash.

Version:

MP4Box - GPAC version 1.1.0-DEV-revUNKNOWN_REV
(c) 2000-2021 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io

Please cite our work in your research:
        GPAC Filters: https://doi.org/10.1145/3339825.3394929
        GPAC: https://doi.org/10.1145/1291233.1291452

GPAC Configuration:
Features: GPAC_CONFIG_LINUX GPAC_64_BITS GPAC_HAS_IPV6 GPAC_HAS_SOCK_UN GPAC_MINIMAL_ODF GPAC_HAS_QJS GPAC_HAS_JPEG GPAC_HAS_PNG GPAC_HAS_LINUX_DVB  GPAC_DISABLE_3D

System information
Ubuntu 20.04 focal, AMD EPYC 7742 64-Core @ 16x 2.25GHz

command:

poc_7.zip

Result

[iso file] extra box maxr found in hinf, deleting
[iso file] extra box maxr found in hinf, deleting
[iso file] Unknown box type 80rak in parent moov
[iso file] Incomplete box mdat - start 11495 size 796203
[iso file] Incomplete file while reading for dump - aborting parsing
[iso file] extra box maxr found in hinf, deleting
[iso file] extra box maxr found in hinf, deleting
[iso file] Unknown box type 80rak in parent moov
[iso file] Incomplete box mdat - start 11495 size 796203
[iso file] Incomplete file while reading for dump - aborting parsing
MPEG-4 BIFS Scene Parsing
[1]    1900424 segmentation fault  ./MP4Box -lsr ./poc/poc_7

gdb

Program received signal SIGSEGV, Segmentation fault.
__strcasecmp_l_avx () at ../sysdeps/x86_64/multiarch/strcmp-sse42.S:199
199     ../sysdeps/x86_64/multiarch/strcmp-sse42.S: No such file or directory.
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x0
 RBX  0x5555555decb0 ◂— 0x0
*RCX  0x17
*RDX  0x7ffff77284a0 (_nl_global_locale) —▸ 0x7ffff77246c0 (_nl_C_LC_CTYPE) —▸ 0x7ffff76f4fc6 (_nl_C_name) ◂— 0x636d656d5f5f0043 /* 'C' */
*RDI  0x0
*RSI  0x7ffff7dfd2d7 ◂— 'startTime'
 R8   0x0
 R9   0x0
*R10  0x7ffff775b844 ◂— 'gf_node_get_tag'
*R11  0x7ffff7849790 (gf_node_get_tag) ◂— endbr64
*R12  0x0
 R13  0x5555555dfe70 —▸ 0x5555555dfed0 ◂— 0x100000067 /* 'g' */
 R14  0x5555555dff50 ◂— 0x21e8e8512be35500
 R15  0x0
*RBP  0x7fffffff6740 ◂— 0x200000002
*RSP  0x7fffffff6688 —▸ 0x7ffff790dc51 (BD_CheckSFTimeOffset+49) ◂— test   eax, eax
*RIP  0x7ffff76c4089 (__strcasecmp_l_avx+69) ◂— vmovdqu xmm1, xmmword ptr [rdi]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
   0x7ffff76c4077 <__strcasecmp_l_avx+51>    vmovdqa xmm6, xmmword ptr [rip + 0x378f1]
   0x7ffff76c407f <__strcasecmp_l_avx+59>    cmp    ecx, 0x30
   0x7ffff76c4082 <__strcasecmp_l_avx+62>    ja     __strcasecmp_l_avx+172                <__strcasecmp_l_avx+172>

   0x7ffff76c4084 <__strcasecmp_l_avx+64>    cmp    eax, 0x30
   0x7ffff76c4087 <__strcasecmp_l_avx+67>    ja     __strcasecmp_l_avx+172                <__strcasecmp_l_avx+172>

 ► 0x7ffff76c4089 <__strcasecmp_l_avx+69>    vmovdqu xmm1, xmmword ptr [rdi]
   0x7ffff76c408d <__strcasecmp_l_avx+73>    vmovdqu xmm2, xmmword ptr [rsi]
   0x7ffff76c4091 <__strcasecmp_l_avx+77>    vpcmpgtb xmm7, xmm1, xmm4
   0x7ffff76c4095 <__strcasecmp_l_avx+81>    vpcmpgtb xmm8, xmm1, xmm5
   0x7ffff76c4099 <__strcasecmp_l_avx+85>    vpcmpgtb xmm9, xmm2, xmm4
   0x7ffff76c409d <__strcasecmp_l_avx+89>    vpcmpgtb xmm10, xmm2, xmm5
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff6688 —▸ 0x7ffff790dc51 (BD_CheckSFTimeOffset+49) ◂— test   eax, eax
01:0008│     0x7fffffff6690 —▸ 0x5555555decb0 ◂— 0x0
02:0010│     0x7fffffff6698 —▸ 0x5555555d26d0 ◂— 0x0
03:0018│     0x7fffffff66a0 —▸ 0x7fffffff6740 ◂— 0x200000002
04:0020│     0x7fffffff66a8 —▸ 0x7ffff790ed35 (gf_bifs_dec_sf_field+2053) ◂— mov    eax, dword ptr [rbx]
05:0028│     0x7fffffff66b0 —▸ 0x5555555dfe90 ◂— 0x11cb
06:0030│     0x7fffffff66b8 ◂— 0x22 /* '"' */
07:0038│     0x7fffffff66c0 ◂— 0x11cb
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff76c4089 __strcasecmp_l_avx+69
   f 1   0x7ffff790dc51 BD_CheckSFTimeOffset+49
   f 2   0x7ffff790ed35 gf_bifs_dec_sf_field+2053
   f 3   0x7ffff790f4c0 BD_DecMFFieldVec+656
   f 4   0x7ffff790fa3f gf_bifs_dec_node_mask+287
   f 5   0x7ffff790e158 gf_bifs_dec_node+936
   f 6   0x7ffff79062f8 gf_bifs_dec_proto_list+1560
   f 7   0x7ffff7906559 BD_DecSceneReplace+73
──────────────────────────────────────────────────────────────────────────────────────────────────────
pwndbg> bt
#0  __strcasecmp_l_avx () at ../sysdeps/x86_64/multiarch/strcmp-sse42.S:199
#1  0x00007ffff790dc51 in BD_CheckSFTimeOffset () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#2  0x00007ffff790ed35 in gf_bifs_dec_sf_field () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#3  0x00007ffff790f4c0 in BD_DecMFFieldVec () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#4  0x00007ffff790fa3f in gf_bifs_dec_node_mask () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#5  0x00007ffff790e158 in gf_bifs_dec_node () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#6  0x00007ffff79062f8 in gf_bifs_dec_proto_list () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#7  0x00007ffff7906559 in BD_DecSceneReplace () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#8  0x00007ffff7914e5e in BM_SceneReplace () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#9  0x00007ffff7915023 in BM_ParseCommand () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#10 0x00007ffff7915353 in gf_bifs_decode_command_list () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#11 0x00007ffff7aa1d91 in gf_sm_load_run_isom () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#12 0x00005555555844a8 in dump_isom_scene ()
#13 0x000055555557b42c in mp4boxMain ()
#14 0x00007ffff75630b3 in __libc_start_main (main=0x55555556c420 <main>, argc=3, argv=0x7fffffffe188, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe178) at ../csu/libc-start.c:308
#15 0x000055555556c45e in _start ()

break BD_CheckSFTimeOffset

0x00007ffff790dc4c in BD_CheckSFTimeOffset () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x67
 RBX  0x5555555decb0 ◂— 0x0
 RCX  0x0
 RDX  0x7fffffff6740 ◂— 0x200000002
*RDI  0x0
 RSI  0x7ffff7dfd2d7 ◂— 'startTime'
 R8   0x0
 R9   0x0
 R10  0x7ffff775b844 ◂— 'gf_node_get_tag'
 R11  0x7ffff7849790 (gf_node_get_tag) ◂— endbr64
 R12  0x0
 R13  0x5555555dfe70 —▸ 0x5555555dfed0 ◂— 0x100000067 /* 'g' */
 R14  0x5555555dff50 ◂— 0x21e8e8512be35500
 R15  0x0
 RBP  0x7fffffff6740 ◂— 0x200000002
 RSP  0x7fffffff6690 —▸ 0x5555555decb0 ◂— 0x0
*RIP  0x7ffff790dc4c (BD_CheckSFTimeOffset+44) ◂— call   0x7ffff77e0db0
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
   0x7ffff790dc39 <BD_CheckSFTimeOffset+25>    cmp    eax, 1
   0x7ffff790dc3c <BD_CheckSFTimeOffset+28>    je     BD_CheckSFTimeOffset+144                <BD_CheckSFTimeOffset+144>

   0x7ffff790dc3e <BD_CheckSFTimeOffset+30>    mov    r12, qword ptr [rbp + 0x10]
   0x7ffff790dc42 <BD_CheckSFTimeOffset+34>    lea    rsi, [rip + 0x4ef68e]
   0x7ffff790dc49 <BD_CheckSFTimeOffset+41>    mov    rdi, r12
 ► 0x7ffff790dc4c <BD_CheckSFTimeOffset+44>    call   strcasecmp@plt                <strcasecmp@plt>
        s1: 0x0
        s2: 0x7ffff7dfd2d7 ◂— 'startTime'

   0x7ffff790dc51 <BD_CheckSFTimeOffset+49>    test   eax, eax
   0x7ffff790dc53 <BD_CheckSFTimeOffset+51>    jne    BD_CheckSFTimeOffset+112                <BD_CheckSFTimeOffset+112>

   0x7ffff790dc55 <BD_CheckSFTimeOffset+53>    mov    edx, dword ptr [rbx + 0x6c]
   0x7ffff790dc58 <BD_CheckSFTimeOffset+56>    test   edx, edx
   0x7ffff790dc5a <BD_CheckSFTimeOffset+58>    jne    BD_CheckSFTimeOffset+80                <BD_CheckSFTimeOffset+80>
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff6690 —▸ 0x5555555decb0 ◂— 0x0
01:0008│     0x7fffffff6698 —▸ 0x5555555d26d0 ◂— 0x0
02:0010│     0x7fffffff66a0 —▸ 0x7fffffff6740 ◂— 0x200000002
03:0018│     0x7fffffff66a8 —▸ 0x7ffff790ed35 (gf_bifs_dec_sf_field+2053) ◂— mov    eax, dword ptr [rbx]
04:0020│     0x7fffffff66b0 —▸ 0x5555555dfe90 ◂— 0x11cb
05:0028│     0x7fffffff66b8 ◂— 0x22 /* '"' */
06:0030│     0x7fffffff66c0 ◂— 0x11cb
07:0038│     0x7fffffff66c8 —▸ 0x7fffffff67d0 ◂— 0x2200000002
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff790dc4c BD_CheckSFTimeOffset+44
   f 1   0x7ffff790ed35 gf_bifs_dec_sf_field+2053
   f 2   0x7ffff790f4c0 BD_DecMFFieldVec+656
   f 3   0x7ffff790fa3f gf_bifs_dec_node_mask+287
   f 4   0x7ffff790e158 gf_bifs_dec_node+936
   f 5   0x7ffff79062f8 gf_bifs_dec_proto_list+1560
   f 6   0x7ffff7906559 BD_DecSceneReplace+73
   f 7   0x7ffff7914e5e BM_SceneReplace+110


Program received signal SIGSEGV, Segmentation fault.
__strcasecmp_l_avx () at ../sysdeps/x86_64/multiarch/strcmp-sse42.S:199
199     in ../sysdeps/x86_64/multiarch/strcmp-sse42.S
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x0
 RBX  0x5555555decb0 ◂— 0x0
 RCX  0x17
 RDX  0x7ffff77284a0 (_nl_global_locale) —▸ 0x7ffff77246c0 (_nl_C_LC_CTYPE) —▸ 0x7ffff76f4fc6 (_nl_C_name) ◂— 0x636d656d5f5f0043 /* 'C' */
 RDI  0x0
 RSI  0x7ffff7dfd2d7 ◂— 'startTime'
 R8   0x0
 R9   0x0
 R10  0x7ffff775b844 ◂— 'gf_node_get_tag'
 R11  0x7ffff7849790 (gf_node_get_tag) ◂— endbr64
 R12  0x0
 R13  0x5555555dfe70 —▸ 0x5555555dfed0 ◂— 0x100000067 /* 'g' */
 R14  0x5555555dff50 ◂— 0x21e8e8512be35500
 R15  0x0
 RBP  0x7fffffff6740 ◂— 0x200000002
 RSP  0x7fffffff6688 —▸ 0x7ffff790dc51 (BD_CheckSFTimeOffset+49) ◂— test   eax, eax
 RIP  0x7ffff76c4089 (__strcasecmp_l_avx+69) ◂— vmovdqu xmm1, xmmword ptr [rdi]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
   0x7ffff76c4077 <__strcasecmp_l_avx+51>    vmovdqa xmm6, xmmword ptr [rip + 0x378f1]
   0x7ffff76c407f <__strcasecmp_l_avx+59>    cmp    ecx, 0x30
   0x7ffff76c4082 <__strcasecmp_l_avx+62>    ja     __strcasecmp_l_avx+172                <__strcasecmp_l_avx+172>

   0x7ffff76c4084 <__strcasecmp_l_avx+64>    cmp    eax, 0x30
   0x7ffff76c4087 <__strcasecmp_l_avx+67>    ja     __strcasecmp_l_avx+172                <__strcasecmp_l_avx+172>

 ► 0x7ffff76c4089 <__strcasecmp_l_avx+69>    vmovdqu xmm1, xmmword ptr [rdi]
   0x7ffff76c408d <__strcasecmp_l_avx+73>    vmovdqu xmm2, xmmword ptr [rsi]
   0x7ffff76c4091 <__strcasecmp_l_avx+77>    vpcmpgtb xmm7, xmm1, xmm4
   0x7ffff76c4095 <__strcasecmp_l_avx+81>    vpcmpgtb xmm8, xmm1, xmm5
   0x7ffff76c4099 <__strcasecmp_l_avx+85>    vpcmpgtb xmm9, xmm2, xmm4
   0x7ffff76c409d <__strcasecmp_l_avx+89>    vpcmpgtb xmm10, xmm2, xmm5
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff6688 —▸ 0x7ffff790dc51 (BD_CheckSFTimeOffset+49) ◂— test   eax, eax
01:0008│     0x7fffffff6690 —▸ 0x5555555decb0 ◂— 0x0
02:0010│     0x7fffffff6698 —▸ 0x5555555d26d0 ◂— 0x0
03:0018│     0x7fffffff66a0 —▸ 0x7fffffff6740 ◂— 0x200000002
04:0020│     0x7fffffff66a8 —▸ 0x7ffff790ed35 (gf_bifs_dec_sf_field+2053) ◂— mov    eax, dword ptr [rbx]
05:0028│     0x7fffffff66b0 —▸ 0x5555555dfe90 ◂— 0x11cb
06:0030│     0x7fffffff66b8 ◂— 0x22 /* '"' */
07:0038│     0x7fffffff66c0 ◂— 0x11cb
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff76c4089 __strcasecmp_l_avx+69
   f 1   0x7ffff790dc51 BD_CheckSFTimeOffset+49
   f 2   0x7ffff790ed35 gf_bifs_dec_sf_field+2053
   f 3   0x7ffff790f4c0 BD_DecMFFieldVec+656
   f 4   0x7ffff790fa3f gf_bifs_dec_node_mask+287
   f 5   0x7ffff790e158 gf_bifs_dec_node+936
   f 6   0x7ffff79062f8 gf_bifs_dec_proto_list+1560
   f 7   0x7ffff7906559 BD_DecSceneReplace+73