{"id":1659,"date":"2017-04-17T19:47:45","date_gmt":"2017-04-17T17:47:45","guid":{"rendered":"http:\/\/blogs.gentoo.org\/ago\/?p=1659"},"modified":"2017-04-30T11:15:20","modified_gmt":"2017-04-30T09:15:20","slug":"imageworsener-divide-by-zero-in-iwgif_record_pixel-imagew-gif-c","status":"publish","type":"post","link":"https:\/\/blogs.gentoo.org\/ago\/2017\/04\/17\/imageworsener-divide-by-zero-in-iwgif_record_pixel-imagew-gif-c\/","title":{"rendered":"imageworsener: divide-by-zero in iwgif_record_pixel (imagew-gif.c)"},"content":{"rendered":"<p><strong>Description<\/strong>:<br \/>\n<a href=\"https:\/\/github.com\/jsummers\/imageworsener\">imageworsener<\/a> is a utility for image scaling and processing.<\/p>\n<p>A fuzz on it discovered a divide-by-zero.<\/p>\n<p>The complete ASan output:<\/p>\n<pre><font size=\"2\"># imagew $FILE \/tmp\/out -outfmt bmp\r\n==20305==ERROR: AddressSanitizer: FPE on unknown address 0x7f8e57340cd6 (pc 0x7f8e57340cd6 bp 0x7ffc0fee8910 sp 0x7ffc0fee87e0 T0)                                                                                \r\n    #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                                                                           \r\n    #1 0x7f8e57340cd5 in lzw_emit_code \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-gif.c:312                                                                                   \r\n    #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                                                                              \r\n    #3 0x7f8e57339a94 in lzw_process_bytes \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-gif.c:433                                                                               \r\n    #4 0x7f8e57339a94 in iwgif_read_image \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-gif.c:669                                                                                \r\n    #5 0x7f8e57339a94 in iwgif_read_main \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-gif.c:724                                                                                 \r\n    #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                                                                              \r\n    #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                                                                       \r\n    #8 0x519304 in iwcmd_run \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-cmd.c:1191:6                                                                                          \r\n    #9 0x515326 in iwcmd_main \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-cmd.c:3018:7                                                                                         \r\n    #10 0x515326 in main \/tmp\/portage\/media-gfx\/imageworsener-1.3.0\/work\/imageworsener-1.3.0\/src\/imagew-cmd.c:3067                                                                                                \r\n    #11 0x7f8e562f078f in __libc_start_main \/tmp\/portage\/sys-libs\/glibc-2.23-r3\/work\/glibc-2.23\/csu\/..\/csu\/libc-start.c:289                                                                                       \r\n    #12 0x41b028 in _init (\/usr\/bin\/imagew+0x41b028)                                                                                                                                                              \r\n                                                                                                                                                                                                                  \r\nAddressSanitizer can not provide additional info.                                                                                                                                                                 \r\nSUMMARY: 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                                                                  \r\n==20305==ABORTING\r\n<\/font><\/pre>\n<p><strong>Affected version:<\/strong><br \/>\n1.3.0<\/p>\n<p><strong>Fixed version:<\/strong><br \/>\n1.3.1<\/p>\n<p><strong>Commit fix:<\/strong><br \/>\n<a href=\"https:\/\/github.com\/jsummers\/imageworsener\/commit\/ca3356eb49fee03e2eaf6b6aff826988c1122d93\">https:\/\/github.com\/jsummers\/imageworsener\/commit\/ca3356eb49fee03e2eaf6b6aff826988c1122d93<\/a><\/p>\n<p><strong>Credit:<\/strong><br \/>\nThis bug was discovered by Agostino Sarubbo of Gentoo.<\/p>\n<p><strong>CVE:<\/strong><br \/>\nCVE-2017-7962<\/p>\n<p><strong>Reproducer:<\/strong><br \/>\n<a href=\"https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00270-imageworsener-FPE-iwgif_record_pixel\">https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00270-imageworsener-FPE-iwgif_record_pixel<\/a><\/p>\n<p><strong>Timeline:<\/strong><br \/>\n2017-04-12: bug discovered and reported to upstream<br \/>\n2017-04-14: upstream released a patch<br \/>\n2017-04-17: blog post about the issue<br \/>\n2017-04-19: CVE assigned<\/p>\n<p><strong>Note:<\/strong><br \/>\nThis bug was found with <a href=\"http:\/\/lcamtuf.coredump.cx\/afl\">American Fuzzy Lop<\/a>.<\/p>\n<p><strong>Permalink:<\/strong><\/p>\n<blockquote data-secret=\"PQThZAvVI6\" class=\"wp-embedded-content\"><p><a href=\"http:\/\/blogs.gentoo.org\/ago\/2017\/04\/17\/imageworsener-divide-by-zero-in-iwgif_record_pixel-imagew-gif-c\/\">imageworsener: divide-by-zero in iwgif_record_pixel (imagew-gif.c)<\/a><\/p><\/blockquote>\n<p><iframe class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" src=\"http:\/\/blogs.gentoo.org\/ago\/2017\/04\/17\/imageworsener-divide-by-zero-in-iwgif_record_pixel-imagew-gif-c\/embed\/#?secret=PQThZAvVI6\" data-secret=\"PQThZAvVI6\" width=\"600\" height=\"338\" title=\"&#8220;imageworsener: divide-by-zero in iwgif_record_pixel (imagew-gif.c)&#8221; &#8212; agostino&#039;s blog\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>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 &hellip; <a href=\"https:\/\/blogs.gentoo.org\/ago\/2017\/04\/17\/imageworsener-divide-by-zero-in-iwgif_record_pixel-imagew-gif-c\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":140,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[12,10],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2EaBc-qL","_links":{"self":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1659"}],"collection":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/users\/140"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/comments?post=1659"}],"version-history":[{"count":4,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1659\/revisions"}],"predecessor-version":[{"id":1716,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1659\/revisions\/1716"}],"wp:attachment":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/media?parent=1659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/categories?post=1659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/tags?post=1659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}