An issue was discovered in GPAC version 0.8.0 and 0.9.0-development-20191109. There is a NULL pointer dereference in the function gf_isom_dump() in isomedia/box_dump.c.
System info:  
Ubuntu 16.04.6 LTS, X64, gcc 5.4.0, gpac (latest master 00dfc93)  
Compile Command:
```
$ CC="gcc -fsanitize=address -g" CXX="g++ -fsanitize=address -g" ./configure --static-mp4box
$ make
```
Run Command:
```
$ MP4Box -diso -out /dev/null $POC-new-gf_isom_dump
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-00dfc93-crashes/POC-new-gf_isom_dump

gdb info:
```C
Error in bin/MP4Box: free(): invalid next size (fast): 0x00000000009cc600
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7ffff73447e5]
/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7ffff734d37a]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7ffff735153c]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7ffff72ed830]
======= Memory map: ========

009c8000-009ec000 rw-p 00000000 00:00 0                                  [heap]
7ffff0000000-7ffff0021000 rw-p 00000000 00:00 0
7ffff0021000-7ffff4000000 ---p 00000000 00:00 0
7ffff70b7000-7ffff70cd000 r-xp 00000000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff70cd000-7ffff72cc000 ---p 00016000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff72cc000-7ffff72cd000 rw-p 00015000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff72cd000-7ffff748d000 r-xp 00000000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff748d000-7ffff768d000 ---p 001c0000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff768d000-7ffff7691000 r--p 001c0000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff7691000-7ffff7693000 rw-p 001c4000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff7693000-7ffff7697000 rw-p 00000000 00:00 0
7ffff7697000-7ffff76b0000 r-xp 00000000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff76b0000-7ffff78af000 ---p 00019000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78af000-7ffff78b0000 r--p 00018000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78b0000-7ffff78b1000 rw-p 00019000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78b1000-7ffff79b9000 r-xp 00000000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff79b9000-7ffff7bb8000 ---p 00108000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bb8000-7ffff7bb9000 r--p 00107000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bb9000-7ffff7bba000 rw-p 00108000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bba000-7ffff7bd2000 r-xp 00000000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7bd2000-7ffff7dd1000 ---p 00018000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd1000-7ffff7dd2000 r--p 00017000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd2000-7ffff7dd3000 rw-p 00018000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd3000-7ffff7dd7000 rw-p 00000000 00:00 0
7ffff7dd7000-7ffff7dfd000 r-xp 00000000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7fdf000-7ffff7fe4000 rw-p 00000000 00:00 0
7ffff7ff7000-7ffff7ff8000 rw-p 00000000 00:00 0
7ffff7ff8000-7ffff7ffa000 r--p 00000000 00:00 0                          [vvar]
7ffff7ffa000-7ffff7ffc000 r-xp 00000000 00:00 0                          [vdso]
7ffff7ffc000-7ffff7ffd000 r--p 00025000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7ffd000-7ffff7ffe000 rw-p 00026000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7ffe000-7ffff7fff000 rw-p 00000000 00:00 0
7ffffffde000-7ffffffff000 rw-p 00000000 00:00 0                          [stack]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

Program received signal SIGABRT, Aborted.
0x00007ffff7302428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
54      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  0x00007ffff7302428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff730402a in __GI_abort () at abort.c:89
#2  0x00007ffff73447ea in __libc_message (do_abort=do_abort@entry=2, fmt=fmt@entry=0x7ffff745ded8 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#3  0x00007ffff734d37a in malloc_printerr (ar_ptr=<optimized out>, ptr=<optimized out>, str=0x7ffff745df50 "free(): invalid next size (fast)", action=3) at malloc.c:5006
#4  _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3867
#5  0x00007ffff735153c in __GI___libc_free (mem=<optimized out>) at malloc.c:2968
#6  0x0000000000512a7d in gf_isom_box_del ()
#7  0x0000000000513eae in gf_isom_parse_root_box ()
#8  0x000000000051b4fe in gf_isom_parse_movie_boxes.part ()
#9  0x000000000051c48c in gf_isom_open_file ()
#10 0x000000000041c082 in mp4boxMain ()
#11 0x00007ffff72ed830 in __libc_start_main (main=0x40eb70 <main>, argc=5, argv=0x7fffffffe328, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe318) at ../csu/libc-start.c:291
#12 0x000000000040eba9 in _start ()

```
ASAN info:
```C
[33m[iso file] Movie fragment but no moov (yet) - possibly broken parsing!
[0m[33m[iso file] Box "tenc" (start 8) has 389 extra bytes
[0m[32m[iso file] Unknown top-level box type ffff
[0m[31m[iso file] Incomplete box ffff - start 532 size 1717986903
[0m[31m[iso file] Incomplete file while reading for dump - aborting parsing
[0m   
ASAN:SIGSEGV
=================================================================
==26000==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x0000006a3968 bp 0x61600000ea80 sp 0x7fffffff8080 T0)
    #0 0x6a3967 in gf_isom_dump isomedia/box_dump.c:133
    #1 0x443b9a in dump_isom_xml /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/filedump.c:1930
    #2 0x43246d in mp4boxMain /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/main.c:4982
    #3 0x7ffff638082f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #4 0x41e228 in _start (/home/aota09/yyp/fuzzcompare/test/gpac/test-crash/bin_asan/bin/MP4Box+0x41e228)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV isomedia/box_dump.c:133 gf_isom_dump
==26000==ABORTING
```
---
Edit

This bug issue still exists in latest version 0.8.0: 4c19ae5 and 0.9.0: 1de1f8d

---

Addition: This bug was found with our fuzzer, which is based on AFL. Our fuzzer is developed by Yuanpingyu(cfenicey@gmail.com) 、Yanhao and Marsman1996(lqliuyuwei@outlook.com)
AddressSanitizer: NULL pointer dereference in gf_isom_dump isomedia/box_dump.c:133
This is a GitHub Issue
repo:gpac
owner:gpac
Title : AddressSanitizer: NULL pointer dereference in gf_isom_dump isomedia/box_dump.c:133
Issue date:

--- start body ---
System info:  
Ubuntu 16.04.6 LTS, X64, gcc 5.4.0, gpac (latest master 00dfc93)  
Compile Command:
```
$ CC="gcc -fsanitize=address -g" CXX="g++ -fsanitize=address -g" ./configure --static-mp4box
$ make
```
Run Command:
```
$ MP4Box -diso -out /dev/null $POC-new-gf_isom_dump
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-00dfc93-crashes/POC-new-gf_isom_dump

gdb info:
```C
Error in bin/MP4Box: free(): invalid next size (fast): 0x00000000009cc600
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7ffff73447e5]
/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7ffff734d37a]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7ffff735153c]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7ffff72ed830]
======= Memory map: ========

009c8000-009ec000 rw-p 00000000 00:00 0                                  [heap]
7ffff0000000-7ffff0021000 rw-p 00000000 00:00 0
7ffff0021000-7ffff4000000 ---p 00000000 00:00 0
7ffff70b7000-7ffff70cd000 r-xp 00000000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff70cd000-7ffff72cc000 ---p 00016000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff72cc000-7ffff72cd000 rw-p 00015000 08:02 67633677                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7ffff72cd000-7ffff748d000 r-xp 00000000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff748d000-7ffff768d000 ---p 001c0000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff768d000-7ffff7691000 r--p 001c0000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff7691000-7ffff7693000 rw-p 001c4000 08:02 67637542                   /lib/x86_64-linux-gnu/libc-2.23.so
7ffff7693000-7ffff7697000 rw-p 00000000 00:00 0
7ffff7697000-7ffff76b0000 r-xp 00000000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff76b0000-7ffff78af000 ---p 00019000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78af000-7ffff78b0000 r--p 00018000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78b0000-7ffff78b1000 rw-p 00019000 08:02 67633774                   /lib/x86_64-linux-gnu/libz.so.1.2.8
7ffff78b1000-7ffff79b9000 r-xp 00000000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff79b9000-7ffff7bb8000 ---p 00108000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bb8000-7ffff7bb9000 r--p 00107000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bb9000-7ffff7bba000 rw-p 00108000 08:02 67637545                   /lib/x86_64-linux-gnu/libm-2.23.so
7ffff7bba000-7ffff7bd2000 r-xp 00000000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7bd2000-7ffff7dd1000 ---p 00018000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd1000-7ffff7dd2000 r--p 00017000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd2000-7ffff7dd3000 rw-p 00018000 08:02 67637529                   /lib/x86_64-linux-gnu/libpthread-2.23.so
7ffff7dd3000-7ffff7dd7000 rw-p 00000000 00:00 0
7ffff7dd7000-7ffff7dfd000 r-xp 00000000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7fdf000-7ffff7fe4000 rw-p 00000000 00:00 0
7ffff7ff7000-7ffff7ff8000 rw-p 00000000 00:00 0
7ffff7ff8000-7ffff7ffa000 r--p 00000000 00:00 0                          [vvar]
7ffff7ffa000-7ffff7ffc000 r-xp 00000000 00:00 0                          [vdso]
7ffff7ffc000-7ffff7ffd000 r--p 00025000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7ffd000-7ffff7ffe000 rw-p 00026000 08:02 67637528                   /lib/x86_64-linux-gnu/ld-2.23.so
7ffff7ffe000-7ffff7fff000 rw-p 00000000 00:00 0
7ffffffde000-7ffffffff000 rw-p 00000000 00:00 0                          [stack]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

Program received signal SIGABRT, Aborted.
0x00007ffff7302428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
54      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  0x00007ffff7302428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff730402a in __GI_abort () at abort.c:89
#2  0x00007ffff73447ea in __libc_message (do_abort=do_abort@entry=2, fmt=fmt@entry=0x7ffff745ded8 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#3  0x00007ffff734d37a in malloc_printerr (ar_ptr=<optimized out>, ptr=<optimized out>, str=0x7ffff745df50 "free(): invalid next size (fast)", action=3) at malloc.c:5006
#4  _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3867
#5  0x00007ffff735153c in __GI___libc_free (mem=<optimized out>) at malloc.c:2968
#6  0x0000000000512a7d in gf_isom_box_del ()
#7  0x0000000000513eae in gf_isom_parse_root_box ()
#8  0x000000000051b4fe in gf_isom_parse_movie_boxes.part ()
#9  0x000000000051c48c in gf_isom_open_file ()
#10 0x000000000041c082 in mp4boxMain ()
#11 0x00007ffff72ed830 in __libc_start_main (main=0x40eb70 <main>, argc=5, argv=0x7fffffffe328, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe318) at ../csu/libc-start.c:291
#12 0x000000000040eba9 in _start ()

```
ASAN info:
```C
[33m[iso file] Movie fragment but no moov (yet) - possibly broken parsing!
[0m[33m[iso file] Box "tenc" (start 8) has 389 extra bytes
[0m[32m[iso file] Unknown top-level box type ffff
[0m[31m[iso file] Incomplete box ffff - start 532 size 1717986903
[0m[31m[iso file] Incomplete file while reading for dump - aborting parsing
[0m   
ASAN:SIGSEGV
=================================================================
==26000==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x0000006a3968 bp 0x61600000ea80 sp 0x7fffffff8080 T0)
    #0 0x6a3967 in gf_isom_dump isomedia/box_dump.c:133
    #1 0x443b9a in dump_isom_xml /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/filedump.c:1930
    #2 0x43246d in mp4boxMain /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/main.c:4982
    #3 0x7ffff638082f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #4 0x41e228 in _start (/home/aota09/yyp/fuzzcompare/test/gpac/test-crash/bin_asan/bin/MP4Box+0x41e228)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV isomedia/box_dump.c:133 gf_isom_dump
==26000==ABORTING
```
---
Edit

This bug issue still exists in latest version 0.8.0: 4c19ae5 and 0.9.0: 1de1f8d

---

Addition: This bug was found with our fuzzer, which is based on AFL. Our fuzzer is developed by Yuanpingyu(cfenicey@gmail.com) 、Yanhao and Marsman1996(lqliuyuwei@outlook.com)
--- end body ---
