CVE-2021-44921: Null Pointer Dereference in gf_isom_parse_movie_boxes_internal() · Issue #1964 · gpac/gpac

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A null pointer dereference was discovered in gf_isom_parse_movie_boxes_internal(). 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_1.zip

Result

[iso file] extra box maxr found in hinf, deleting
[iso file] Read Box type 00000000 (0x00000000) at position 4494 has size 0 but is not at root/file level, skipping
[iso file] Read Box "hinf" (start 4390) failed (End Of Stream / File) - skipping
[iso file] Read Box "udta" (start 4178) failed (End Of Stream / File) - skipping
[iso file] Read Box "trak" (start 2229) failed (End Of Stream / File) - skipping
[iso file] Read Box "moov" (start 20) failed (End Of Stream / File) - skipping
[1]    2155243 segmentation fault  ./MP4Box -lsr ./poc/poc_1

gdb

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7973829 in gf_isom_parse_movie_boxes_internal () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x1
 RBX  0x5555555c72a0 ◂— 0x0
 RCX  0x7ffff764d1e7 (write+23) ◂— cmp    rax, -0x1000 /* 'H=' */
 RDX  0x0
 RDI  0x5555555c62a0 ◂— 0x0
 RSI  0x0
 R8   0x0
 R9   0x0
 R10  0x7ffff7e227df ◂— ') - skipping\n'
 R11  0x246
 R12  0x0
 R13  0x0
 R14  0x5555555c72a0 ◂— 0x0
 R15  0x3
 RBP  0x7fffffff83a0 ◂— 0x0
 RSP  0x7fffffff8310 —▸ 0x7fffffff8350 ◂— 0x0
 RIP  0x7ffff7973829 (gf_isom_parse_movie_boxes_internal+249) ◂— mov    eax, dword ptr [rsi]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
 ► 0x7ffff7973829 <gf_isom_parse_movie_boxes_internal+249>     mov    eax, dword ptr [rsi]
   0x7ffff797382b <gf_isom_parse_movie_boxes_internal+251>     cmp    eax, 0x6d6f6f76
   0x7ffff7973830 <gf_isom_parse_movie_boxes_internal+256>     je     gf_isom_parse_movie_boxes_internal+1688                <gf_isom_parse_movie_boxes_internal+1688>
    ↓
   0x7ffff7973dc8 <gf_isom_parse_movie_boxes_internal+1688>    cmp    qword ptr [r14 + 0x48], 0
   0x7ffff7973dcd <gf_isom_parse_movie_boxes_internal+1693>    jne    gf_isom_parse_movie_boxes_internal+4630                <gf_isom_parse_movie_boxes_internal+4630>
    ↓
   0x7ffff7974946 <gf_isom_parse_movie_boxes_internal+4630>    mov    esi, 1
   0x7ffff797494b <gf_isom_parse_movie_boxes_internal+4635>    mov    edi, 2
   0x7ffff7974950 <gf_isom_parse_movie_boxes_internal+4640>    call   gf_log_tool_level_on@plt                <gf_log_tool_level_on@plt>

   0x7ffff7974955 <gf_isom_parse_movie_boxes_internal+4645>    test   eax, eax
   0x7ffff7974957 <gf_isom_parse_movie_boxes_internal+4647>    je     gf_isom_parse_movie_boxes_internal+4540                <gf_isom_parse_movie_boxes_internal+4540>

   0x7ffff7974959 <gf_isom_parse_movie_boxes_internal+4649>    mov    esi, 2
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff8310 —▸ 0x7fffffff8350 ◂— 0x0
01:0008│     0x7fffffff8318 ◂— 0x0
... ↓        2 skipped
04:0020│     0x7fffffff8330 —▸ 0x5555555c7500 ◂— 0x6d703431 /* '14pm' */
05:0028│     0x7fffffff8338 ◂— 0x0
06:0030│     0x7fffffff8340 ◂— 0x0
07:0038│     0x7fffffff8348 ◂— 0x4
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff7973829 gf_isom_parse_movie_boxes_internal+249
   f 1   0x7ffff7974f97 gf_isom_open_file+311
   f 2   0x55555557dc14 mp4boxMain+19444
   f 3   0x7ffff75630b3 __libc_start_main+243
──────────────────────────────────────────────────────────────────────────────────────────────────────
pwndbg> bt
#0  0x00007ffff7973829 in gf_isom_parse_movie_boxes_internal () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#1  0x00007ffff7974f97 in gf_isom_open_file () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#2  0x000055555557dc14 in mp4boxMain ()
#3  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
#4  0x000055555556c45e in _start ()