{"id":1363,"date":"2017-02-20T16:30:00","date_gmt":"2017-02-20T14:30:00","guid":{"rendered":"http:\/\/blogs.gentoo.org\/ago\/?p=1363"},"modified":"2017-03-13T11:07:23","modified_gmt":"2017-03-13T09:07:23","slug":"audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp","status":"publish","type":"post","link":"https:\/\/blogs.gentoo.org\/ago\/2017\/02\/20\/audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp\/","title":{"rendered":"audiofile: heap-based buffer overflow in alaw2linear_buf (G711.cpp)"},"content":{"rendered":"<p><strong>Description<\/strong>:<br \/>\n<a href=\"http:\/\/www.68k.org\/~michael\/audiofile\/\">audiofile<\/a> is a C-based library for reading and writing audio files in many common formats.<\/p>\n<p>A fuzz on it discovered an heap overflow.<\/p>\n<p>The complete ASan output:<\/p>\n<pre><font size=\"2\"># sfconvert @@ out.mp3 format aiff\r\n==2480==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f5eb894d800 at pc 0x7f5eb85a699f bp 0x7ffe19064df0 sp 0x7ffe19064de8\r\nWRITE of size 2 at 0x7f5eb894d800 thread T0\r\n    #0 0x7f5eb85a699e in alaw2linear_buf(unsigned char const*, short*, int) \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/libaudiofile\/modules\/G711.cpp:54:13\r\n    #1 0x7f5eb85a699e in G711::runPull() \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/libaudiofile\/modules\/G711.cpp:209\r\n    #2 0x7f5eb858d05a in afReadFrames \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/libaudiofile\/data.cpp:222:14\r\n    #3 0x50bbeb in copyaudiodata \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/sfcommands\/sfconvert.c:340:29\r\n    #4 0x50b050 in main \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/sfcommands\/sfconvert.c:248:17\r\n    #5 0x7f5eb766278f in __libc_start_main \/tmp\/portage\/sys-libs\/glibc-2.23-r3\/work\/glibc-2.23\/csu\/..\/csu\/libc-start.c:289\r\n    #6 0x419f48 in _init (\/usr\/bin\/sfconvert+0x419f48)\r\n\r\n0x7f5eb894d800 is located 0 bytes to the right of 393216-byte region [0x7f5eb88ed800,0x7f5eb894d800)\r\nallocated by thread T0 here:\r\n    #0 0x4d2d08 in malloc \/tmp\/portage\/sys-devel\/llvm-3.9.1-r1\/work\/llvm-3.9.1.src\/projects\/compiler-rt\/lib\/asan\/asan_malloc_linux.cc:64\r\n    #1 0x50bb48 in copyaudiodata \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/sfcommands\/sfconvert.c:327:17\r\n    #2 0x50b050 in main \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/sfcommands\/sfconvert.c:248:17\r\n    #3 0x7f5eb766278f in __libc_start_main \/tmp\/portage\/sys-libs\/glibc-2.23-r3\/work\/glibc-2.23\/csu\/..\/csu\/libc-start.c:289\r\n\r\nSUMMARY: AddressSanitizer: heap-buffer-overflow \/tmp\/portage\/media-libs\/audiofile-0.3.6-r1\/work\/audiofile-0.3.6\/libaudiofile\/modules\/G711.cpp:54:13 in alaw2linear_buf(unsigned char const*, short*, int)\r\nShadow bytes around the buggy address:\r\n  0x0fec57121ab0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0fec57121ac0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0fec57121ad0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0fec57121ae0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0fec57121af0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n=&gt;0x0fec57121b00:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0fec57121b10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0fec57121b20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0fec57121b30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0fec57121b40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0fec57121b50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\nShadow byte legend (one shadow byte represents 8 application bytes):\r\n  Addressable:           00\r\n  Partially addressable: 01 02 03 04 05 06 07 \r\n  Heap left redzone:       fa\r\n  Heap right redzone:      fb\r\n  Freed heap region:       fd\r\n  Stack left redzone:      f1\r\n  Stack mid redzone:       f2\r\n  Stack right redzone:     f3\r\n  Stack partial redzone:   f4\r\n  Stack after return:      f5\r\n  Stack use after scope:   f8\r\n  Global redzone:          f9\r\n  Global init order:       f6\r\n  Poisoned by user:        f7\r\n  Container overflow:      fc\r\n  Array cookie:            ac\r\n  Intra object redzone:    bb\r\n  ASan internal:           fe\r\n  Left alloca redzone:     ca\r\n  Right alloca redzone:    cb\r\n==2480==ABORTING\r\n<\/font><\/pre>\n<p><strong>Affected version:<\/strong><br \/>\n0.3.6<\/p>\n<p><strong>Fixed version:<\/strong><br \/>\nN\/A<\/p>\n<p><strong>Commit fix:<\/strong><br \/>\nN\/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-2017-6830<\/p>\n<p><strong>Reproducer:<\/strong><br \/>\n<a href=\"https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00184-audiofile-heapoverflow-alaw2linear_buf\">https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00184-audiofile-heapoverflow-alaw2linear_buf<\/a>                                                                                <\/p>\n<p><strong>Timeline:<\/strong><br \/>\n2017-02-20: bug discovered and reported to upstream<br \/>\n2017-02-20: blog post about the issue<br \/>\n2017-03-12: 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=\"nwArylxlIH\" class=\"wp-embedded-content\"><p><a href=\"http:\/\/blogs.gentoo.org\/ago\/2017\/02\/20\/audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp\/\">audiofile: heap-based buffer overflow in alaw2linear_buf (G711.cpp)<\/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\/02\/20\/audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp\/embed\/#?secret=nwArylxlIH\" data-secret=\"nwArylxlIH\" width=\"600\" height=\"338\" title=\"&#8220;audiofile: heap-based buffer overflow in alaw2linear_buf (G711.cpp)&#8221; &#8212; agostino&#039;s blog\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Description: audiofile is a C-based library for reading and writing audio files in many common formats. A fuzz on it discovered an heap overflow. The complete ASan output: # sfconvert @@ out.mp3 format aiff ==2480==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f5eb894d800 &hellip; <a href=\"https:\/\/blogs.gentoo.org\/ago\/2017\/02\/20\/audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp\/\">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-lZ","_links":{"self":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1363"}],"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=1363"}],"version-history":[{"count":4,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1363\/revisions"}],"predecessor-version":[{"id":1433,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/1363\/revisions\/1433"}],"wp:attachment":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/media?parent=1363"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/categories?post=1363"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/tags?post=1363"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}