Headline
CVE-2021-44923: Null Pointer Dereference in gf_dump_vrml_dyn_field.isra() · Issue #1962 · gpac/gpac
A null pointer dereference vulnerability exists in gpac 1.1.0 in the gf_dump_vrml_dyn_field.isra function, which causes a segmentation fault and application crash.
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A null pointer dereference was discovered in gf_dump_vrml_dyn_field.isra(). 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:
poc4.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 860238
[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 860238
[iso file] Incomplete file while reading for dump - aborting parsing
MPEG-4 BIFS Scene Parsing
Scene loaded - dumping 1 systems streams
[1] 414421 segmentation fault ./MP4Box -lsr ./poc4
gdb
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7ac0797 in gf_dump_vrml_dyn_field.isra () from /root/fuckit/test/gpac-master/bin/gcc/libgpac.so.10
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
RAX 0xa
RBX 0x0
RCX 0x0
RDX 0x7ffff72bf040 ◂— 0x7ffff72bf040
RDI 0x7fffffff6af0 —▸ 0x7ffff75a21e0 (funlockfile) ◂— endbr64
RSI 0x0
R8 0xffffffff
R9 0xa
R10 0x7ffff7e37a2a ◂— 0x3e73252f3c00223d /* '="' */
R11 0x7ffff7df0c38 ◂— 0x6e776f6e6b6e75 /* 'unknown' */
R12 0x0
R13 0x0
R14 0x5555555ded60 —▸ 0x5555555d43b0 ◂— 0x0
R15 0x1
RBP 0x3c
RSP 0x7fffffff7060 ◂— 0x3000000010
RIP 0x7ffff7ac0797 (gf_dump_vrml_dyn_field.isra+631) ◂— mov eax, dword ptr [r12]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
► 0x7ffff7ac0797 <gf_dump_vrml_dyn_field.isra+631> mov eax, dword ptr [r12]
0x7ffff7ac079b <gf_dump_vrml_dyn_field.isra+635> test eax, eax
0x7ffff7ac079d <gf_dump_vrml_dyn_field.isra+637> je gf_dump_vrml_dyn_field.isra+720
<gf_dump_vrml_dyn_field.isra+720>
↓
0x7ffff7ac07f0 <gf_dump_vrml_dyn_field.isra+720> mov eax, dword ptr [rsp + 0x70]
0x7ffff7ac07f4 <gf_dump_vrml_dyn_field.isra+724> mov rdi, qword ptr [r14 + 0x10]
0x7ffff7ac07f8 <gf_dump_vrml_dyn_field.isra+728> test eax, eax
0x7ffff7ac07fa <gf_dump_vrml_dyn_field.isra+730> jne gf_dump_vrml_dyn_field.isra+292
<gf_dump_vrml_dyn_field.isra+292>
↓
0x7ffff7ac0644 <gf_dump_vrml_dyn_field.isra+292> lea rsi, [rip + 0x35ac0b]
0x7ffff7ac064b <gf_dump_vrml_dyn_field.isra+299> xor eax, eax
0x7ffff7ac064d <gf_dump_vrml_dyn_field.isra+301> call gf_fprintf@plt <gf_fprintf@plt>
0x7ffff7ac0652 <gf_dump_vrml_dyn_field.isra+306> jmp gf_dump_vrml_dyn_field.isra+391
<gf_dump_vrml_dyn_field.isra+391>
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff7060 ◂— 0x3000000010
01:0008│ 0x7fffffff7068 —▸ 0x5555555df880 ◂— 0x31646c6569665f /* '_field1' */
02:0010│ 0x7fffffff7070 ◂— 0x0
03:0018│ 0x7fffffff7078 ◂— 0x38b85a8f00
04:0020│ 0x7fffffff7080 ◂— 0x0
05:0028│ 0x7fffffff7088 ◂— 0x7aa5d2dbb85a8f00
06:0030│ 0x7fffffff7090 ◂— 0x1
07:0038│ 0x7fffffff7098 —▸ 0x7ffff7e27f46 ◂— 0x65646f6d73006325 /* '%c' */
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
► f 0 0x7ffff7ac0797 gf_dump_vrml_dyn_field.isra+631
f 1 0x7ffff7ac15d1 DumpProtos+305
f 2 0x7ffff7abb389 gf_sm_dump_command_list+857
f 3 0x7ffff7ac24fc gf_sm_dump+1116
f 4 0x555555584418 dump_isom_scene+616
f 5 0x55555557b42c mp4boxMain+9228
f 6 0x7ffff75630b3 __libc_start_main+243
──────────────────────────────────────────────────────────────────────────────────────────────────────
pwndbg> bt
#0 0x00007ffff7ac0797 in gf_dump_vrml_dyn_field.isra () from /root/fuckit/test/gpac-master/bin/gcc/libgpac.so.10
#1 0x00007ffff7ac15d1 in DumpProtos () from /root/fuckit/test/gpac-master/bin/gcc/libgpac.so.10
#2 0x00007ffff7abb389 in gf_sm_dump_command_list () from /root/fuckit/test/gpac-master/bin/gcc/libgpac.so.10
#3 0x00007ffff7ac24fc in gf_sm_dump () from /root/fuckit/test/gpac-master/bin/gcc/libgpac.so.10
#4 0x0000555555584418 in dump_isom_scene ()
#5 0x000055555557b42c in mp4boxMain ()
#6 0x00007ffff75630b3 in __libc_start_main (main=0x55555556c420 <main>, argc=3, argv=0x7fffffffe1a8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe198) at ../csu/libc-start.c:308
#7 0x000055555556c45e in _start ()