==26572==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1b55fdd320 at pc 0x0000004d90f2 bp 0x7ffd65666ef0 sp 0x7ffd656666a0
READ of size 1526074725 at 0x7f1b55fdd320 thread T0
#0 0x4d90f1 in __asan_memcpy (/home/tmp/img2sixel+0x4d90f1)
#1 0x7f1c0acb8341 in sixel_encoder_output_without_macro /home/tmp/libsixel/src/encoder.c:814:5
#2 0x7f1c0acb8341 in sixel_encoder_encode_frame /home/tmp/libsixel/src/encoder.c:1050
#3 0x7f1c0ac8f026 in load_gif /home/tmp/libsixel/src/fromgif.c:649:22
#4 0x7f1c0aa6c6fb in load_with_builtin /home/tmp/libsixel/src/loader.c:888:18
#5 0x7f1c0aa6c6fb in sixel_helper_load_image_file /home/tmp/libsixel/src/loader.c:1392
#6 0x7f1c0acb099f 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 0x7f1c09016b96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
#9 0x41a379 in _start (/home/tmp/img2sixel+0x41a379)
0x7f1b55fdd320 is located 0 bytes to the right of 36043552-byte region [0x7f1b53d7d800,0x7f1b55fdd320)
allocated by thread T0 here:
#0 0x4da230 in __interceptor_malloc (/home/tmp/img2sixel+0x4da230)
#1 0x7f1c0ac8ce95 in gif_init_frame /home/tmp/libsixel/src/fromgif.c:239:42
#2 0x7f1c0ac8ce95 in load_gif /home/tmp/libsixel/src/fromgif.c:644
#3 0x7f1c0aa6c6fb in load_with_builtin /home/tmp/libsixel/src/loader.c:888:18
#4 0x7f1c0aa6c6fb in sixel_helper_load_image_file /home/tmp/libsixel/src/loader.c:1392
#5 0x7f1c0acb099f in sixel_encoder_encode /home/tmp/libsixel/src/encoder.c:1737:14
#6 0x51787f in main /home/tmp/libsixel/converters/img2sixel.c:457:22
#7 0x7f1c09016b96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/tmp/img2sixel+0x4d90f1) in __asan_memcpy
Shadow bytes around the buggy address:
0x0fe3eabf3a10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe3eabf3a20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe3eabf3a30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe3eabf3a40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe3eabf3a50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0fe3eabf3a60: 00 00 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa
0x0fe3eabf3a70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe3eabf3a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe3eabf3a90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe3eabf3aa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe3eabf3ab0: 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
==26572==ABORTING
version : img2sixel 1.8.4 OS : Ubuntu 18.04 configured with: libcurl: yes libpng: yes libjpeg: yes gdk-pixbuf2: no GD: no
There is a heap-buffer-overflow in sixel_encoder_output_without_macro at encoder.c:814 please run following cmd to reproduce it.
poc ASAN LOG