The GetHintFormat function in GPAC 1.0.1 allows attackers to cause a denial of service via a crafted file in the MP4Box command.

- [x] I looked for a similar issue and couldn't find any.
- [x] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...).


It's a heap-buffer-overflow  bug 

Step to reproduce:
1.get latest commit code (GPAC version 1.1.0-DEV-rev1170-g592ba26-master)
2.compile with --enable-sanitizer
3.run ./MP4BOX info poc


Env:
Ubunut 20.04 , clang 12.0.1

ASAN report

```
==2275020==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x604000000638 at pc 0x7f1c17ca68a4 bp 0x7ffd52eab1d0 sp 0x7ffd52eab1c8
READ of size 4 at 0x604000000638 thread T0
    #0 0x7f1c17ca68a3 in GetHintFormat /home/lly/pro/gpac_public/src/isomedia/hint_track.c:46:22
    #1 0x7f1c17ca68a3 in CheckHintFormat /home/lly/pro/gpac_public/src/isomedia/hint_track.c:58:6
    #2 0x7f1c17ca68a3 in gf_isom_get_payt_count /home/lly/pro/gpac_public/src/isomedia/hint_track.c:979:7
    #3 0x5b52e5 in DumpTrackInfo /home/lly/pro/gpac_public/applications/mp4box/filedump.c:3178:14
    #4 0x5e4af1 in DumpMovieInfo /home/lly/pro/gpac_public/applications/mp4box/filedump.c:3789:3
    #5 0x52ea16 in mp4boxMain /home/lly/pro/gpac_public/applications/mp4box/main.c:6023:9
    #6 0x7f1c15d710b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #7 0x429aad in _start (/home/lly/pro/gpac_public/bin/gcc/MP4Box+0x429aad)

0x604000000638 is located 0 bytes to the right of 40-byte region [0x604000000610,0x604000000638)
allocated by thread T0 here:
    #0 0x4a496d in malloc (/home/lly/pro/gpac_public/bin/gcc/MP4Box+0x4a496d)
    #1 0x7f1c17543a17 in nmhd_box_new /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:4651:2
    #2 0x7f1c1775de4f in gf_isom_box_new_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1673:6
    #3 0x7f1c17756209 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:239:12
    #4 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #5 0x7f1c1751e43a in minf_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:3527:6
    #6 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #7 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #8 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #9 0x7f1c17511b3d in mdia_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:3078:6
    #10 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #11 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #12 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #13 0x7f1c17582c10 in trak_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:6734:6
    #14 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #15 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #16 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #17 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #18 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #19 0x7f1c177548b9 in gf_isom_parse_root_box /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:38:8
    #20 0x7f1c177e2347 in gf_isom_parse_movie_boxes_internal /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:320:7
    #21 0x7f1c177e2347 in gf_isom_parse_movie_boxes /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:781:6
    #22 0x7f1c177f84d3 in gf_isom_open_file /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:901:19
    #23 0x53c4b8 in mp4boxMain /home/lly/pro/gpac_public/applications/mp4box/main.c:5841:12
    #24 0x7f1c15d710b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/lly/pro/gpac_public/src/isomedia/hint_track.c:46:22 in GetHintFormat
Shadow bytes around the buggy address:
  0x0c087fff8070: fa fa 00 00 00 00 04 fa fa fa 00 00 00 00 00 00
  0x0c087fff8080: fa fa 00 00 00 00 00 00 fa fa 00 00 00 00 00 00
  0x0c087fff8090: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80a0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80b0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
=>0x0c087fff80c0: fa fa 00 00 00 00 00[fa]fa fa 00 00 00 00 00 00
  0x0c087fff80d0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80e0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 fa
  0x0c087fff80f0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff8100: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff8110: fa fa 00 00 00 00 00 00 fa fa 00 00 00 00 00 00
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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  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
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc

```
[poc.zip](https://github.com/gpac/gpac/files/7051614/poc.zip)

heap-buffer-overflow in MP4BOX at souce file src/isomedia/hint_track.c:46
This is a GitHub Issue
repo:gpac
owner:gpac
Title : heap-buffer-overflow in MP4BOX at souce file src/isomedia/hint_track.c:46
Issue date:

--- start body ---

- [x] I looked for a similar issue and couldn't find any.
- [x] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...).


It's a heap-buffer-overflow  bug 

Step to reproduce:
1.get latest commit code (GPAC version 1.1.0-DEV-rev1170-g592ba26-master)
2.compile with --enable-sanitizer
3.run ./MP4BOX info poc


Env:
Ubunut 20.04 , clang 12.0.1

ASAN report

```
==2275020==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x604000000638 at pc 0x7f1c17ca68a4 bp 0x7ffd52eab1d0 sp 0x7ffd52eab1c8
READ of size 4 at 0x604000000638 thread T0
    #0 0x7f1c17ca68a3 in GetHintFormat /home/lly/pro/gpac_public/src/isomedia/hint_track.c:46:22
    #1 0x7f1c17ca68a3 in CheckHintFormat /home/lly/pro/gpac_public/src/isomedia/hint_track.c:58:6
    #2 0x7f1c17ca68a3 in gf_isom_get_payt_count /home/lly/pro/gpac_public/src/isomedia/hint_track.c:979:7
    #3 0x5b52e5 in DumpTrackInfo /home/lly/pro/gpac_public/applications/mp4box/filedump.c:3178:14
    #4 0x5e4af1 in DumpMovieInfo /home/lly/pro/gpac_public/applications/mp4box/filedump.c:3789:3
    #5 0x52ea16 in mp4boxMain /home/lly/pro/gpac_public/applications/mp4box/main.c:6023:9
    #6 0x7f1c15d710b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #7 0x429aad in _start (/home/lly/pro/gpac_public/bin/gcc/MP4Box+0x429aad)

0x604000000638 is located 0 bytes to the right of 40-byte region [0x604000000610,0x604000000638)
allocated by thread T0 here:
    #0 0x4a496d in malloc (/home/lly/pro/gpac_public/bin/gcc/MP4Box+0x4a496d)
    #1 0x7f1c17543a17 in nmhd_box_new /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:4651:2
    #2 0x7f1c1775de4f in gf_isom_box_new_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1673:6
    #3 0x7f1c17756209 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:239:12
    #4 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #5 0x7f1c1751e43a in minf_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:3527:6
    #6 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #7 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #8 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #9 0x7f1c17511b3d in mdia_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:3078:6
    #10 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #11 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #12 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #13 0x7f1c17582c10 in trak_box_read /home/lly/pro/gpac_public/src/isomedia/box_code_base.c:6734:6
    #14 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #15 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #16 0x7f1c17760a0b in gf_isom_box_array_read_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1707:7
    #17 0x7f1c17757fe8 in gf_isom_box_read /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:1810:9
    #18 0x7f1c17757fe8 in gf_isom_box_parse_ex /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:263:14
    #19 0x7f1c177548b9 in gf_isom_parse_root_box /home/lly/pro/gpac_public/src/isomedia/box_funcs.c:38:8
    #20 0x7f1c177e2347 in gf_isom_parse_movie_boxes_internal /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:320:7
    #21 0x7f1c177e2347 in gf_isom_parse_movie_boxes /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:781:6
    #22 0x7f1c177f84d3 in gf_isom_open_file /home/lly/pro/gpac_public/src/isomedia/isom_intern.c:901:19
    #23 0x53c4b8 in mp4boxMain /home/lly/pro/gpac_public/applications/mp4box/main.c:5841:12
    #24 0x7f1c15d710b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/lly/pro/gpac_public/src/isomedia/hint_track.c:46:22 in GetHintFormat
Shadow bytes around the buggy address:
  0x0c087fff8070: fa fa 00 00 00 00 04 fa fa fa 00 00 00 00 00 00
  0x0c087fff8080: fa fa 00 00 00 00 00 00 fa fa 00 00 00 00 00 00
  0x0c087fff8090: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80a0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80b0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
=>0x0c087fff80c0: fa fa 00 00 00 00 00[fa]fa fa 00 00 00 00 00 00
  0x0c087fff80d0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff80e0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 fa
  0x0c087fff80f0: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff8100: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 00 00
  0x0c087fff8110: fa fa 00 00 00 00 00 00 fa fa 00 00 00 00 00 00
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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  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
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc

```
[poc.zip](https://github.com/gpac/gpac/files/7051614/poc.zip)

--- end body ---
