Bento4 1.5.1.0 has a NULL pointer dereference in AP4_DescriptorListInspector::Action in Core/Ap4Descriptor.h, related to AP4_IodsAtom::InspectFields in Core/Ap4IodsAtom.cpp, as demonstrated by mp4dump.
**System Details**
Commit ID: bc1b02a
Test Machine : Ubuntu 16.04.3 LTS
MP4 File Dumper - Version 1.2
(Bento4 Version 1.5.1.0)

**Command**
mp4dump --verbosity 2 POC-file

**ASAN Output**
```
ASAN:DEADLYSIGNAL
=================================================================
==12343==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x00000054cbf4 bp 0x7fff4ca92010 sp 0x7fff4ca91f30 T0)
    #0 0x54cbf3 in AP4_DescriptorListInspector::Action(AP4_Descriptor*) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Descriptor.h:124:9
    #1 0x69aa85 in AP4_List<AP4_Descriptor>::Apply(AP4_List<AP4_Descriptor>::Item::Operator const&) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4List.h:353:9
    #2 0x69aa85 in AP4_InitialObjectDescriptor::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4ObjectDescriptor.cpp:327
    #3 0x586b12 in AP4_IodsAtom::InspectFields(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4IodsAtom.cpp:112:9
    #4 0x53e7a4 in AP4_Atom::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.cpp:263:5
    #5 0x57843c in AP4_AtomListInspector::Action(AP4_Atom*) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.h:532:9
    #6 0x673506 in AP4_List<AP4_Atom>::Apply(AP4_List<AP4_Atom>::Item::Operator const&) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4List.h:353:9
    #7 0x673506 in AP4_ContainerAtom::InspectChildren(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4ContainerAtom.cpp:220
    #8 0x53e7a4 in AP4_Atom::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.cpp:263:5
    #9 0x5283ae in main /home/fuzzer/victim/Bento4/Source/C++/Apps/Mp4Dump/Mp4Dump.cpp:350:9
    #10 0x7efe540e182f in __libc_start_main /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:291
    #11 0x451258 in _start (/home/fuzzer/victim/Bento4/mp4dump+0x451258)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Descriptor.h:124:9 in AP4_DescriptorListInspector::Action(AP4_Descriptor*) const
==12343==ABORTING
```
SEGV in mp4dump
This is a GitHub Issue
repo:Bento4
owner:axiomatic-systems
Title : SEGV in mp4dump
Issue date:

--- start body ---
**System Details**
Commit ID: bc1b02a
Test Machine : Ubuntu 16.04.3 LTS
MP4 File Dumper - Version 1.2
(Bento4 Version 1.5.1.0)

**Command**
mp4dump --verbosity 2 POC-file

**ASAN Output**
```
ASAN:DEADLYSIGNAL
=================================================================
==12343==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x00000054cbf4 bp 0x7fff4ca92010 sp 0x7fff4ca91f30 T0)
    #0 0x54cbf3 in AP4_DescriptorListInspector::Action(AP4_Descriptor*) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Descriptor.h:124:9
    #1 0x69aa85 in AP4_List<AP4_Descriptor>::Apply(AP4_List<AP4_Descriptor>::Item::Operator const&) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4List.h:353:9
    #2 0x69aa85 in AP4_InitialObjectDescriptor::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4ObjectDescriptor.cpp:327
    #3 0x586b12 in AP4_IodsAtom::InspectFields(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4IodsAtom.cpp:112:9
    #4 0x53e7a4 in AP4_Atom::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.cpp:263:5
    #5 0x57843c in AP4_AtomListInspector::Action(AP4_Atom*) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.h:532:9
    #6 0x673506 in AP4_List<AP4_Atom>::Apply(AP4_List<AP4_Atom>::Item::Operator const&) const /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4List.h:353:9
    #7 0x673506 in AP4_ContainerAtom::InspectChildren(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4ContainerAtom.cpp:220
    #8 0x53e7a4 in AP4_Atom::Inspect(AP4_AtomInspector&) /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Atom.cpp:263:5
    #9 0x5283ae in main /home/fuzzer/victim/Bento4/Source/C++/Apps/Mp4Dump/Mp4Dump.cpp:350:9
    #10 0x7efe540e182f in __libc_start_main /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:291
    #11 0x451258 in _start (/home/fuzzer/victim/Bento4/mp4dump+0x451258)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/fuzzer/victim/Bento4/Source/C++/Core/Ap4Descriptor.h:124:9 in AP4_DescriptorListInspector::Action(AP4_Descriptor*) const
==12343==ABORTING
```
--- end body ---
