GPAC v2.3-DEV-rev566-g50c2ab06f-master was discovered to contain a heap-use-after-free via the flush_ref_samples function at /gpac/src/isomedia/movie_fragments.c.
# Version
```
$ ./MP4Box -version
MP4Box - GPAC version 2.3-DEV-rev566-g50c2ab06f-master
```

# Platform
```
$ uname -a
Linux user-GE40-2PC-Dragon-Eyes 6.2.0-33-generic #33~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Sep  7 10:33:52 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
```

# Asan
```
[33m[iso file] extra box maxr found in hinf, deleting
[0m[32m[iso file] Unknown box type traI in parent moov
[0m[33m[iso file] Box "stss" (start 9939) has 32 extra bytes
[0m[33m[iso file] extra box maxr found in hinf, deleting
[0m[33m[iso file] Track with no sample description box !
[0m[33m[IsoMedia] Track 4 type MPEG not natively handled
[0m[32m[Dasher] No template assigned, using $File$_dash$FS$$Number$
[0m[32m[iso file] Unknown box type traI in parent moov
[0m[33m[MP4Mux] muxing unknown codec ID Codec Not Supported, using generic sample entry with 4CC "MPEG"
[0m[31m[IsoMedia] File truncated, aborting read for track 1
[0m[37mDashing P1 AS#1.1(V) done (1 segs)
[0m[31m[MP4Mux] Failed to add sample DTS 0 from O7 - prev DTS 18446744073709551615: Out Of Memory
[0m=================================================================
==836900==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b000001d88 at pc 0x7f57c0120bf1 bp 0x7ffeac405a70 sp 0x7ffeac405a68
READ of size 8 at 0x60b000001d88 thread T0
    #0 0x7f57c0120bf0 in flush_ref_samples /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:936:37
    #1 0x7f57c0128df2 in gf_isom_close_segment /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:2331:4
    #2 0x7f57c0cfd198 in mp4_mux_process_fragmented /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:6734:8
    #3 0x7f57c0cf46f3 in mp4_mux_process /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:7273:14
    #4 0x7f57c09afa33 in gf_filter_process_task /home/user/fuzzing_gpac/gpac/src/filter_core/filter.c:2971:7
    #5 0x7f57c097d47b in gf_fs_thread_proc /home/user/fuzzing_gpac/gpac/src/filter_core/filter_session.c:2105:3
    #6 0x7f57c097b5cf in gf_fs_run /home/user/fuzzing_gpac/gpac/src/filter_core/filter_session.c:2405:3
    #7 0x7f57c022ac6a in gf_dasher_process /home/user/fuzzing_gpac/gpac/src/media_tools/dash_segmenter.c:1236:6
    #8 0x55ff536546dc in do_dash /home/user/fuzzing_gpac/gpac/applications/mp4box/mp4box.c:4831:15
    #9 0x55ff53645b6e in mp4box_main /home/user/fuzzing_gpac/gpac/applications/mp4box/mp4box.c:6245:7
    #10 0x7f57bf229d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #11 0x7f57bf229e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #12 0x55ff5356ddd4 in _start (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x82dd4) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)

0x60b000001d88 is located 104 bytes inside of 112-byte region [0x60b000001d20,0x60b000001d90)
freed by thread T0 here:
    #0 0x55ff535f0972 in free (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x105972) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)
    #1 0x7f57c001e6f5 in gf_isom_box_del /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:2005:3

previously allocated by thread T0 here:
    #0 0x55ff535f0c1e in malloc (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x105c1e) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)
    #1 0x7f57bff95c5a in trun_box_new /home/user/fuzzing_gpac/gpac/src/isomedia/box_code_base.c:7805:2
    #2 0x7f57c0026335 in gf_isom_box_new /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:1896:9
    #3 0x7f57c0026335 in gf_isom_box_new_parent /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:2351:14
    #4 0x7f57c0d06f05 in mp4_mux_process_sample /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:4915:9
    #5 0x7f57c0cf85a4 in mp4_mux_process_fragmented /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:6653:8
    #6 0x7f57c0cf46f3 in mp4_mux_process /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:7273:14
    #7 0x7f57c09afa33 in gf_filter_process_task /home/user/fuzzing_gpac/gpac/src/filter_core/filter.c:2971:7

SUMMARY: AddressSanitizer: heap-use-after-free /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:936:37 in flush_ref_samples
Shadow bytes around the buggy address:
  0x0c167fff8360: fa fa 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c167fff8370: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c167fff8380: 00 00 00 00 05 fa fa fa fa fa fa fa fa fa 00 00
  0x0c167fff8390: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
  0x0c167fff83a0: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c167fff83b0: fd[fd]fa fa fa fa fa fa fa fa fd fd fd fd fd fd
  0x0c167fff83c0: fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa fa
  0x0c167fff83d0: fd fd fd fd fd fd fd fd fd fd fd fd fd fa fa fa
  0x0c167fff83e0: fa fa fa fa fa fa fd fd fd fd fd fd fd fd fd fd
  0x0c167fff83f0: fd fd fd fd fa fa fa fa fa fa fa fa fd fd fd fd
  0x0c167fff8400: fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa 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
  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
==836900==ABORTING
```

# Reproduce
```
./MP4Box -dash 10000 poc
```
 
# POC File
https://github.com/gandalf4a/crash_report/blob/main/gpac/MP4Box/huaf_936

# Credit
```
Gandalf4a
```
heap-use-after-free in ./gpac/src/isomedia/movie_fragments.c:936:37 in flush_ref_samples
This is a GitHub Issue
repo:gpac
owner:gpac
Title : heap-use-after-free in ./gpac/src/isomedia/movie_fragments.c:936:37 in flush_ref_samples
Issue date:

--- start body ---
# Version
```
$ ./MP4Box -version
MP4Box - GPAC version 2.3-DEV-rev566-g50c2ab06f-master
```

# Platform
```
$ uname -a
Linux user-GE40-2PC-Dragon-Eyes 6.2.0-33-generic #33~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Sep  7 10:33:52 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
```

# Asan
```
[33m[iso file] extra box maxr found in hinf, deleting
[0m[32m[iso file] Unknown box type traI in parent moov
[0m[33m[iso file] Box "stss" (start 9939) has 32 extra bytes
[0m[33m[iso file] extra box maxr found in hinf, deleting
[0m[33m[iso file] Track with no sample description box !
[0m[33m[IsoMedia] Track 4 type MPEG not natively handled
[0m[32m[Dasher] No template assigned, using $File$_dash$FS$$Number$
[0m[32m[iso file] Unknown box type traI in parent moov
[0m[33m[MP4Mux] muxing unknown codec ID Codec Not Supported, using generic sample entry with 4CC "MPEG"
[0m[31m[IsoMedia] File truncated, aborting read for track 1
[0m[37mDashing P1 AS#1.1(V) done (1 segs)
[0m[31m[MP4Mux] Failed to add sample DTS 0 from O7 - prev DTS 18446744073709551615: Out Of Memory
[0m=================================================================
==836900==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b000001d88 at pc 0x7f57c0120bf1 bp 0x7ffeac405a70 sp 0x7ffeac405a68
READ of size 8 at 0x60b000001d88 thread T0
    #0 0x7f57c0120bf0 in flush_ref_samples /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:936:37
    #1 0x7f57c0128df2 in gf_isom_close_segment /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:2331:4
    #2 0x7f57c0cfd198 in mp4_mux_process_fragmented /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:6734:8
    #3 0x7f57c0cf46f3 in mp4_mux_process /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:7273:14
    #4 0x7f57c09afa33 in gf_filter_process_task /home/user/fuzzing_gpac/gpac/src/filter_core/filter.c:2971:7
    #5 0x7f57c097d47b in gf_fs_thread_proc /home/user/fuzzing_gpac/gpac/src/filter_core/filter_session.c:2105:3
    #6 0x7f57c097b5cf in gf_fs_run /home/user/fuzzing_gpac/gpac/src/filter_core/filter_session.c:2405:3
    #7 0x7f57c022ac6a in gf_dasher_process /home/user/fuzzing_gpac/gpac/src/media_tools/dash_segmenter.c:1236:6
    #8 0x55ff536546dc in do_dash /home/user/fuzzing_gpac/gpac/applications/mp4box/mp4box.c:4831:15
    #9 0x55ff53645b6e in mp4box_main /home/user/fuzzing_gpac/gpac/applications/mp4box/mp4box.c:6245:7
    #10 0x7f57bf229d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #11 0x7f57bf229e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #12 0x55ff5356ddd4 in _start (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x82dd4) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)

0x60b000001d88 is located 104 bytes inside of 112-byte region [0x60b000001d20,0x60b000001d90)
freed by thread T0 here:
    #0 0x55ff535f0972 in free (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x105972) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)
    #1 0x7f57c001e6f5 in gf_isom_box_del /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:2005:3

previously allocated by thread T0 here:
    #0 0x55ff535f0c1e in malloc (/home/user/fuzzing_gpac/gpac/bin/gcc/MP4Box+0x105c1e) (BuildId: 53333ca7bff59dd9a3d1b2821e7c5f3a9aac76b9)
    #1 0x7f57bff95c5a in trun_box_new /home/user/fuzzing_gpac/gpac/src/isomedia/box_code_base.c:7805:2
    #2 0x7f57c0026335 in gf_isom_box_new /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:1896:9
    #3 0x7f57c0026335 in gf_isom_box_new_parent /home/user/fuzzing_gpac/gpac/src/isomedia/box_funcs.c:2351:14
    #4 0x7f57c0d06f05 in mp4_mux_process_sample /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:4915:9
    #5 0x7f57c0cf85a4 in mp4_mux_process_fragmented /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:6653:8
    #6 0x7f57c0cf46f3 in mp4_mux_process /home/user/fuzzing_gpac/gpac/src/filters/mux_isom.c:7273:14
    #7 0x7f57c09afa33 in gf_filter_process_task /home/user/fuzzing_gpac/gpac/src/filter_core/filter.c:2971:7

SUMMARY: AddressSanitizer: heap-use-after-free /home/user/fuzzing_gpac/gpac/src/isomedia/movie_fragments.c:936:37 in flush_ref_samples
Shadow bytes around the buggy address:
  0x0c167fff8360: fa fa 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c167fff8370: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c167fff8380: 00 00 00 00 05 fa fa fa fa fa fa fa fa fa 00 00
  0x0c167fff8390: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
  0x0c167fff83a0: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c167fff83b0: fd[fd]fa fa fa fa fa fa fa fa fd fd fd fd fd fd
  0x0c167fff83c0: fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa fa
  0x0c167fff83d0: fd fd fd fd fd fd fd fd fd fd fd fd fd fa fa fa
  0x0c167fff83e0: fa fa fa fa fa fa fd fd fd fd fd fd fd fd fd fd
  0x0c167fff83f0: fd fd fd fd fa fa fa fa fa fa fa fa fd fd fd fd
  0x0c167fff8400: fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa 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
  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
==836900==ABORTING
```

# Reproduce
```
./MP4Box -dash 10000 poc
```
 
# POC File
https://github.com/gandalf4a/crash_report/blob/main/gpac/MP4Box/huaf_936

# Credit
```
Gandalf4a
```
--- end body ---
