Description:
imageworsener is a utility for image scaling and processing.
A fuzz on it discovered a divide-by-zero.
The complete ASan output:
# imagew $FILE /tmp/out -outfmt bmp
==20305==ERROR: AddressSanitizer: FPE on unknown address 0x7f8e57340cd6 (pc 0x7f8e57340cd6 bp 0x7ffc0fee8910 sp 0x7ffc0fee87e0 T0)
#0 0x7f8e57340cd5 in iwgif_record_pixel /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:213:13
#1 0x7f8e57340cd5 in lzw_emit_code /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:312
#2 0x7f8e57339a94 in lzw_process_code /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:376:3
#3 0x7f8e57339a94 in lzw_process_bytes /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:433
#4 0x7f8e57339a94 in iwgif_read_image /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:669
#5 0x7f8e57339a94 in iwgif_read_main /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:724
#6 0x7f8e5732fb71 in iw_read_gif_file /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:773:6
#7 0x7f8e572e9091 in iw_read_file_by_fmt /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-allfmts.c:61:12
#8 0x519304 in iwcmd_run /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:1191:6
#9 0x515326 in iwcmd_main /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:3018:7
#10 0x515326 in main /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:3067
#11 0x7f8e562f078f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
#12 0x41b028 in _init (/usr/bin/imagew+0x41b028)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: FPE /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-gif.c:213:13 in iwgif_record_pixel
==20305==ABORTING
Affected version:
1.3.0
Fixed version:
1.3.1
Commit fix:
https://github.com/jsummers/imageworsener/commit/ca3356eb49fee03e2eaf6b6aff826988c1122d93
Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.
CVE:
CVE-2017-7962
Reproducer:
https://github.com/asarubbo/poc/blob/master/00270-imageworsener-FPE-iwgif_record_pixel
Timeline:
2017-04-12: bug discovered and reported to upstream
2017-04-14: upstream released a patch
2017-04-17: blog post about the issue
2017-04-19: CVE assigned
Note:
This bug was found with American Fuzzy Lop.
Permalink:
imageworsener: divide-by-zero in iwgif_record_pixel (imagew-gif.c)