==39700==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7fcc6219e808 at pc 0x7fcc6ad13008 bp 0x7ffe2a935b70 sp 0x7ffe2a935b68
READ of size 1 at 0x7fcc6219e808 thread T0
#0 0x7fcc6ad13007 in dither_func_fs /home/tmp/libsixel/src/tosixel.c:861:9
#1 0x7fcc6ad13007 in sixel_apply_15bpp_dither /home/tmp/libsixel/src/tosixel.c:1223
#2 0x7fcc6ad13007 in sixel_encode_highcolor /home/tmp/libsixel/src/tosixel.c:1334
#3 0x7fcc6ad13007 in sixel_encode /home/tmp/libsixel/src/tosixel.c:1485
#4 0x7fcc6b0478a4 in sixel_encoder_output_without_macro /home/tmp/libsixel/src/encoder.c:820:14
#5 0x7fcc6b0478a4 in sixel_encoder_encode_frame /home/tmp/libsixel/src/encoder.c:1050
#6 0x7fcc6adfdd91 in sixel_helper_load_image_file /home/tmp/libsixel/src/loader.c:913:14
#7 0x7fcc6b03fd4f in sixel_encoder_encode /home/tmp/libsixel/src/encoder.c:1737:14
#8 0x51787f in main /home/tmp/libsixel/converters/img2sixel.c:457:22
#9 0x7fcc693a2b96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
#10 0x41a379 in _start (/home/tmp/img2sixel+0x41a379)
0x7fcc6219e808 is located 0 bytes to the right of 573448-byte region [0x7fcc62112800,0x7fcc6219e808)
allocated by thread T0 here:
#0 0x4da230 in __interceptor_malloc (/home/tmp/img2sixel+0x4da230)
#1 0x7fcc6acfcc7f in sixel_encode_highcolor /home/tmp/libsixel/src/tosixel.c:1309:40
#2 0x7fcc6acfcc7f in sixel_encode /home/tmp/libsixel/src/tosixel.c:1485
#3 0x7fcc6b0478a4 in sixel_encoder_output_without_macro /home/tmp/libsixel/src/encoder.c:820:14
#4 0x7fcc6b0478a4 in sixel_encoder_encode_frame /home/tmp/libsixel/src/encoder.c:1050
#5 0x7fcc6adfdd91 in sixel_helper_load_image_file /home/tmp/libsixel/src/loader.c:913:14
#6 0x7fcc6b03fd4f in sixel_encoder_encode /home/tmp/libsixel/src/encoder.c:1737:14
#7 0x51787f in main /home/tmp/libsixel/converters/img2sixel.c:457:22
#8 0x7fcc693a2b96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/tmp/libsixel/src/tosixel.c:861:9 in dither_func_fs
Shadow bytes around the buggy address:
0x0ffa0c42bcb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffa0c42bcc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffa0c42bcd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffa0c42bce0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffa0c42bcf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ffa0c42bd00: 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0ffa0c42bd10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0ffa0c42bd20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0ffa0c42bd30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0ffa0c42bd40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0ffa0c42bd50: 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
==39700==ABORTING
version : img2sixel 1.8.2
There is a heap-buffer-overflow in dither_func_fs at tosixel.c:861 please run following cmd to reproduce it.
poc ASAN LOG