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 ilst_item_Read() in isomedia/box_code_apple.c.
Hello, I found a similar issue but I am not sure they are the same.
https://github.com/gpac/gpac/issues/1263

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-ilst_item_Read
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-00dfc93-crashes/POC-new-ilst_item_Read

gdb info:
```C
Program received signal SIGSEGV, Segmentation fault.
0x00000000006c499d in ilst_item_Read ()
(gdb) bt
#0  0x00000000006c499d in ilst_item_Read ()
#1  0x00000000005137e1 in gf_isom_box_parse_ex.constprop ()
#2  0x0000000000513e15 in gf_isom_parse_root_box ()
#3  0x000000000051b4fe in gf_isom_parse_movie_boxes.part ()
#4  0x000000000051c48c in gf_isom_open_file ()
#5  0x000000000041c082 in mp4boxMain ()
#6  0x00007ffff72ed830 in __libc_start_main (main=0x40eb70 <main>, argc=5, argv=0x7fffffffe318, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe308) at ../csu/libc-start.c:291
#7  0x000000000040eba9 in _start ()
```
ASAN info:
```C
ASAN:SIGSEGV
=================================================================
==27902==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x000000ac4185 bp 0x7fffffff8230 sp 0x7fffffff8220 T0)
    #0 0xac4184 in ilst_item_Read isomedia/box_code_apple.c:119
    #1 0x6c5114 in gf_isom_box_read isomedia/box_funcs.c:1528
    #2 0x6c5114 in gf_isom_box_parse_ex isomedia/box_funcs.c:208
    #3 0x6c5974 in gf_isom_parse_root_box isomedia/box_funcs.c:42
    #4 0x6da6a0 in gf_isom_parse_movie_boxes isomedia/isom_intern.c:206
    #5 0x6dd2f3 in gf_isom_parse_movie_boxes isomedia/isom_intern.c:194
    #6 0x6dd2f3 in gf_isom_open_file isomedia/isom_intern.c:615
    #7 0x42f88a in mp4boxMain /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/main.c:4767
    #8 0x7ffff638082f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #9 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_code_apple.c:119 ilst_item_Read
==27902==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)
ERROR: AddressSanitizer: NULL pointer dereference in ilst_item_Read isomedia/box_code_apple.c:119
This is a GitHub Issue
repo:gpac
owner:gpac
Title : ERROR: AddressSanitizer: NULL pointer dereference in ilst_item_Read isomedia/box_code_apple.c:119
Issue date:

--- start body ---
Hello, I found a similar issue but I am not sure they are the same.
https://github.com/gpac/gpac/issues/1263

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-ilst_item_Read
```
POC file:  
https://github.com/Clingto/POC/blob/master/gpac-MP4Box/gpac-00dfc93-crashes/POC-new-ilst_item_Read

gdb info:
```C
Program received signal SIGSEGV, Segmentation fault.
0x00000000006c499d in ilst_item_Read ()
(gdb) bt
#0  0x00000000006c499d in ilst_item_Read ()
#1  0x00000000005137e1 in gf_isom_box_parse_ex.constprop ()
#2  0x0000000000513e15 in gf_isom_parse_root_box ()
#3  0x000000000051b4fe in gf_isom_parse_movie_boxes.part ()
#4  0x000000000051c48c in gf_isom_open_file ()
#5  0x000000000041c082 in mp4boxMain ()
#6  0x00007ffff72ed830 in __libc_start_main (main=0x40eb70 <main>, argc=5, argv=0x7fffffffe318, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe308) at ../csu/libc-start.c:291
#7  0x000000000040eba9 in _start ()
```
ASAN info:
```C
ASAN:SIGSEGV
=================================================================
==27902==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x000000ac4185 bp 0x7fffffff8230 sp 0x7fffffff8220 T0)
    #0 0xac4184 in ilst_item_Read isomedia/box_code_apple.c:119
    #1 0x6c5114 in gf_isom_box_read isomedia/box_funcs.c:1528
    #2 0x6c5114 in gf_isom_box_parse_ex isomedia/box_funcs.c:208
    #3 0x6c5974 in gf_isom_parse_root_box isomedia/box_funcs.c:42
    #4 0x6da6a0 in gf_isom_parse_movie_boxes isomedia/isom_intern.c:206
    #5 0x6dd2f3 in gf_isom_parse_movie_boxes isomedia/isom_intern.c:194
    #6 0x6dd2f3 in gf_isom_open_file isomedia/isom_intern.c:615
    #7 0x42f88a in mp4boxMain /home/aota09/yyp/fuzzcompare/test/gpac/test-crash/build_asan_00dfc93/applications/mp4box/main.c:4767
    #8 0x7ffff638082f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #9 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_code_apple.c:119 ilst_item_Read
==27902==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 ---
