imageworsener: memory allocation failure in my_mallocfn (imagew-cmd.c)

["Agostino Sarubbo" <ago () gentoo org>]

Description:
imageworsener is a utility for image scaling and processing.

There is a memory allocation failure, I will show the interesting ASan output,

# imagew $FILE /tmp/out -outfmt bmp
    #8 0x551fc0 in my_mallocfn 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:794:9
    #9 0x7f37f140c9ae in iw_malloc_ex 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-util.c:48:8
    #10 0x7f37f140cdec in iw_malloc_large 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-util.c:77:9
    #11 0x7f37f136d66c in bmpr_read_uncompressed 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-bmp.c:665:32
    #12 0x7f37f134ce64 in iwbmp_read_bits 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-bmp.c:910:7
    #13 0x7f37f134ce64 in iw_read_bmp_file 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-bmp.c:980
    #14 0x7f37f1349f94 in iw_read_file_by_fmt 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-allfmts.c:66:12
    #15 0x519304 in iwcmd_run 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:1191:6
    #16 0x515326 in iwcmd_main 
/tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:3018:7
    #17 0x515326 in main /tmp/portage/media-gfx/imageworsener-1.3.0/work/imageworsener-1.3.0/src/imagew-cmd.c:3067
    #18 0x7f37f035178f in __libc_start_main 
/tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #19 0x41b028 in _init (/usr/bin/imagew+0x41b028)

Affected version:
1.3.0

Fixed version:
1.3.1

Commit fix:
https://github.com/jsummers/imageworsener/commit/86564051db45b466e5f667111ce00b5eeedc8fb6

Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.

CVE:
CVE-2017-8327

Reproducer:
https://github.com/asarubbo/poc/blob/master/00276-imageworsener-memallocfailure

Timeline:
2017-04-13: bug discovered and reported to upstream
2017-04-12: upstream released a patch for another issue that fixes this issue too
2017-04-27: blog post about the issue
2017-04-29: CVE assigned

Note:
This bug was found with American Fuzzy Lop.

Permalink:
https://blogs.gentoo.org/ago/2017/04/27/imageworsener-memory-allocation-failure-in-my_mallocfn-imagew-cmd-c/

--
Agostino Sarubbo
Gentoo Linux Developer