divide-by-zero in iwgif_record_pixel (imagew-gif.c)

[asarubbo]

On 1.3.0:

# 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

Reproducer:
https://github.com/asarubbo/poc/blob/master/00270-imageworsener-FPE-iwgif_record_pixel

[jsummers]

Should be fixed by commit ca3356e.

[asarubbo]

Thanks for the fix. Since there was fixed some security bugs, a new release would help packagers. Thanks.

[jsummers]

I plan to make a new release soon, within a week or so.

[rshariffdeen]

This bug has been assigned CVE-2017-7962