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==25754==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60400000054d at pc 0x000000510311 bp 0x7fff615f9850 sp 0x7fff615f9848
READ of size 1 at 0x60400000054d thread T0
#0 0x510310 in write_png_to_file /home/wencheng/Documents/FuzzingObject/libsixel/src/writer.c:140:22
#1 0x510310 in sixel_helper_write_image_file /home/wencheng/Documents/FuzzingObject/libsixel/src/writer.c:322
#2 0x50e373 in sixel_decoder_decode /home/wencheng/Documents/FuzzingObject/libsixel/src/decoder.c:318:14
#3 0x50c8fc in main /home/wencheng/Documents/FuzzingObject/libsixel/converters/sixel2png.c:226:14
#4 0x7fb00c79482f in __libc_start_main /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:291
#5 0x419fa8 in _start (/home/wencheng/Documents/FuzzingObject/libsixel/build/bin/sixel2png+0x419fa8)
Address 0x60400000054d is a wild pointer.
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/wencheng/Documents/FuzzingObject/libsixel/src/writer.c:140:22 in write_png_to_file
Shadow bytes around the buggy address:
0x0c087fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff8080: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff8090: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c087fff80a0: fa fa fa fa fa fa fa fa fa[fa]fa fa fa fa fa fa
0x0c087fff80b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff80d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff80e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c087fff80f0: fa fa fa fa fa fa fa fa fa fa 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
==25754==ABORTING
POC: POC.zip
Reproduce:
sixel2png $POC