An issue was discovered in GPAC version 0.8.0 and 1.0.1. There is heap-based buffer overflow in the function gp_rtp_builder_do_avc() in ietf/rtp_pck_mpeg4.c.
System info:  
Ubuntu 16.04.6 LTS, X64, gcc 5.4.0, gpac (latest master c4f8bc6e and latest V1.0.1 d8538e8)  
I think it is probably due to an imcomplete fix of  [#1483](https://github.com/gpac/gpac/issues/1483) 

Compile Command:
```
$ CC="gcc -fsanitize=address -g" CXX="g++ -fsanitize=address -g" ./configure --static-mp4box --extra-ldflags="-ldl -g"
$ make
```
Run Command:
```
$ MP4Box -hint $gp_rtp_builder_do_avc-hepo -out /dev/null 
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-c4f8bc6e_poc/gp_rtp_builder_do_avc-hepo


ASAN info:
```C
==39148==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000dca9 at pc 0x000000fe1693 bp 0x7ffc75309fc0 sp 0x7ffc75309fb0
READ of size 1 at 0x60300000dca9 thread T0
    #0 0xfe1692 in gp_rtp_builder_do_avc ietf/rtp_pck_mpeg4.c:436
    #1 0x92b813 in gf_hinter_track_process media_tools/isom_hinter.c:796
    #2 0x418d5d in HintFile /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:1446
    #3 0x42bdc7 in mp4boxMain /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:6641
    #4 0x7fac0705783f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
    #5 0x417638 in _start (/opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/build/bin/MP4Box+0x417638)

0x60300000dca9 is located 0 bytes to the right of 25-byte region [0x60300000dc90,0x60300000dca9)
allocated by thread T0 here:
    #0 0x7fac07fff602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x7b69e5 in Media_GetSample isomedia/media.c:573
    #2 0x7602dc in gf_isom_get_sample_ex isomedia/isom_read.c:1808
    #3 0x92b36d in gf_hinter_track_process media_tools/isom_hinter.c:721
    #4 0x418d5d in HintFile /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:1446
    #5 0x42bdc7 in mp4boxMain /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:6641
    #6 0x7fac0705783f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)

SUMMARY: AddressSanitizer: heap-buffer-overflow ietf/rtp_pck_mpeg4.c:436 gp_rtp_builder_do_avc
Shadow bytes around the buggy address:
  0x0c067fff9b40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b80: fa fa fa fa fa fa fa fa fa fa fa fa 00 00 04 fa
=>0x0c067fff9b90: fa fa 00 00 00[01]fa fa fd fd fd fa fa fa fd fd
  0x0c067fff9ba0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
  0x0c067fff9bb0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
  0x0c067fff9bc0: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd
  0x0c067fff9bd0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
  0x0c067fff9be0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
==39148==ABORTING
```
Addition: This bug was found with our fuzzer, which is based on AFL. Our fuzzer is developed by Yuanpingyu(cfenicey@gmail.com) 、Xiangkun Jia(xiangkun@iscas.ac.cn) 、Marsman1996(lqliuyuwei@outlook.com) and Yanhao.
AddressSanitizer: heap-buffer-overflow in gp_rtp_builder_do_avc ietf/rtp_pck_mpeg4.c:436
This is a GitHub Issue
repo:gpac
owner:gpac
Title : AddressSanitizer: heap-buffer-overflow in gp_rtp_builder_do_avc ietf/rtp_pck_mpeg4.c:436
Issue date:

--- start body ---
System info:  
Ubuntu 16.04.6 LTS, X64, gcc 5.4.0, gpac (latest master c4f8bc6e and latest V1.0.1 d8538e8)  
I think it is probably due to an imcomplete fix of  [#1483](https://github.com/gpac/gpac/issues/1483) 

Compile Command:
```
$ CC="gcc -fsanitize=address -g" CXX="g++ -fsanitize=address -g" ./configure --static-mp4box --extra-ldflags="-ldl -g"
$ make
```
Run Command:
```
$ MP4Box -hint $gp_rtp_builder_do_avc-hepo -out /dev/null 
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-c4f8bc6e_poc/gp_rtp_builder_do_avc-hepo


ASAN info:
```C
==39148==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000dca9 at pc 0x000000fe1693 bp 0x7ffc75309fc0 sp 0x7ffc75309fb0
READ of size 1 at 0x60300000dca9 thread T0
    #0 0xfe1692 in gp_rtp_builder_do_avc ietf/rtp_pck_mpeg4.c:436
    #1 0x92b813 in gf_hinter_track_process media_tools/isom_hinter.c:796
    #2 0x418d5d in HintFile /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:1446
    #3 0x42bdc7 in mp4boxMain /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:6641
    #4 0x7fac0705783f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
    #5 0x417638 in _start (/opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/build/bin/MP4Box+0x417638)

0x60300000dca9 is located 0 bytes to the right of 25-byte region [0x60300000dc90,0x60300000dca9)
allocated by thread T0 here:
    #0 0x7fac07fff602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x7b69e5 in Media_GetSample isomedia/media.c:573
    #2 0x7602dc in gf_isom_get_sample_ex isomedia/isom_read.c:1808
    #3 0x92b36d in gf_hinter_track_process media_tools/isom_hinter.c:721
    #4 0x418d5d in HintFile /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:1446
    #5 0x42bdc7 in mp4boxMain /opt/data/yyp/fuzzsequence/test/0-day/SRC_asan/applications/mp4box/main.c:6641
    #6 0x7fac0705783f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)

SUMMARY: AddressSanitizer: heap-buffer-overflow ietf/rtp_pck_mpeg4.c:436 gp_rtp_builder_do_avc
Shadow bytes around the buggy address:
  0x0c067fff9b40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9b80: fa fa fa fa fa fa fa fa fa fa fa fa 00 00 04 fa
=>0x0c067fff9b90: fa fa 00 00 00[01]fa fa fd fd fd fa fa fa fd fd
  0x0c067fff9ba0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
  0x0c067fff9bb0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
  0x0c067fff9bc0: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd
  0x0c067fff9bd0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
  0x0c067fff9be0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
==39148==ABORTING
```
Addition: This bug was found with our fuzzer, which is based on AFL. Our fuzzer is developed by Yuanpingyu(cfenicey@gmail.com) 、Xiangkun Jia(xiangkun@iscas.ac.cn) 、Marsman1996(lqliuyuwei@outlook.com) and Yanhao.
--- end body ---
