null pointer dereference in Component::SubXOf in component.hpp

[sleicasper]

reproduce steps

1. compile libjpeg with address sanitizer
2. run ./jpeg ./poc /dev/null

poc

poc.zip

stack trace

=================================================================
==3114171==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000000c (pc 0x562098ed89e0 bp 0x7ffc18eca130 sp 0x7ffc18eca120 T0)
==3114171==The signal is caused by a READ memory access.
==3114171==Hint: address points to the zero page.
    #0 0x562098ed89df in Component::SubXOf() const ../marker/component.hpp:145
    #1 0x562098f2a796 in PredictiveScan::FindComponentDimensions() /home/casper/targets/struct/libjpeg_th/source/SRC/codestream/predictivescan.cpp:113
    #2 0x562098f2b7b3 in LosslessScan::StartParseScan(ByteStream*, Checksum*, BufferCtrl*) /home/casper/targets/struct/libjpeg_th/source/SRC/codestream/losslessscan.cpp:111
    #3 0x562098f61d3c in Scan::StartParseScan(ByteStream*, Checksum*, BufferCtrl*) /home/casper/targets/struct/libjpeg_th/source/SRC/marker/scan.cpp:981
    #4 0x562098f553fe in Frame::StartParseScan(ByteStream*, Checksum*) /home/casper/targets/struct/libjpeg_th/source/SRC/marker/frame.cpp:847
    #5 0x562098eda266 in JPEG::ReadInternal(JPG_TagItem*) /home/casper/targets/struct/libjpeg_th/source/SRC/interface/jpeg.cpp:296
    #6 0x562098ed9779 in JPEG::Read(JPG_TagItem*) /home/casper/targets/struct/libjpeg_th/source/SRC/interface/jpeg.cpp:210
    #7 0x562098ebed38 in Reconstruct(char const*, char const*, int, char const*, bool) /home/casper/targets/struct/libjpeg_th/source/SRC/cmd/reconstruct.cpp:121
    #8 0x562098eacea9 in main /home/casper/targets/struct/libjpeg_th/source/SRC/cmd/main.cpp:747
    #9 0x7fbacbbb3082 in __libc_start_main ../csu/libc-start.c:308
    #10 0x562098ea99ad in _start (/home/casper/targets/struct/libjpeg_th/source/SRC/jpeg+0x459ad)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV ../marker/component.hpp:145 in Component::SubXOf() const
==3114171==ABORTING

[thorfdbg]

Thanks, has been addressed and fixed.

[thorfdbg]

Done.