{"id":361,"date":"2016-02-16T16:52:24","date_gmt":"2016-02-16T14:52:24","guid":{"rendered":"http:\/\/blogs.gentoo.org\/ago\/?p=361"},"modified":"2016-08-01T15:00:11","modified_gmt":"2016-08-01T13:00:11","slug":"portage-utils-stack-based-buffer-overflow-in-qfile-c","status":"publish","type":"post","link":"https:\/\/blogs.gentoo.org\/ago\/2016\/02\/16\/portage-utils-stack-based-buffer-overflow-in-qfile-c\/","title":{"rendered":"portage-utils: stack-based buffer overflow in qfile.c"},"content":{"rendered":"<p><strong>Description<\/strong>:<br \/>\n<a href=\"https:\/\/wiki.gentoo.org\/wiki\/Portage-utils\">Portage-utils<\/a> is small and fast portage helper tools written in C.<\/p>\n<p>I discovered that a crafted file is able to cause a stack-based buffer overflow.<\/p>\n<p>The complete ASan output:<\/p>\n<pre><font size=\"2\">~ # qfile -f qfile-OOB-crash.log                                                                                                                                                                                                                                          \r\n=================================================================                                                                                                                                                                                                              \r\n==12240==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffd067c1ac1 at pc 0x000000495bdc bp 0x7ffd067bd6f0 sp 0x7ffd067bceb0                                                                                                                                     \r\nREAD of size 4095 at 0x7ffd067c1ac1 thread T0                                                                                                                                                                                                                                  \r\n    #0 0x495bdb in strncpy \/var\/tmp\/portage\/sys-devel\/llvm-3.7.1\/work\/llvm-3.7.1.src\/projects\/compiler-rt\/lib\/asan\/asan_interceptors.cc:632:5                                                                                                                                  \r\n    #1 0x4fb5b9 in prepare_qfile_args \/tmp\/portage\/app-portage\/portage-utils-0.60\/work\/portage-utils-0.60\/.\/qfile.c:297:3                                                                                                                                                      \r\n    #2 0x4fb5b9 in qfile_main \/tmp\/portage\/app-portage\/portage-utils-0.60\/work\/portage-utils-0.60\/.\/qfile.c:530                                                                                                                                                                \r\n    #3 0x4e7f22 in q_main \/tmp\/portage\/app-portage\/portage-utils-0.60\/work\/portage-utils-0.60\/.\/q.c:79:10                                                                                                                                                                      \r\n    #4 0x4e7afe in main \/tmp\/portage\/app-portage\/portage-utils-0.60\/work\/portage-utils-0.60\/main.c:1405:9                                                                                                                                                                      \r\n    #5 0x7f5ccc29e854 in __libc_start_main \/tmp\/portage\/sys-libs\/glibc-2.21-r1\/work\/glibc-2.21\/csu\/libc-start.c:289                                                                                                                                                            \r\n    #6 0x4192f8 in _init (\/usr\/bin\/q+0x4192f8)                                                                                                                                                                                                                                 \r\n                                                                                                                                                                                                                                                                               \r\nAddress 0x7ffd067c1ac1 is located in stack of thread T0 at offset 17345 in frame                                                                                                                                                                                               \r\n    #0 0x4f8b3f in qfile_main \/tmp\/portage\/app-portage\/portage-utils-0.60\/work\/portage-utils-0.60\/.\/qfile.c:394                                                                                                                                                                \r\n                                                                                                                                                                                                                                                                               \r\n  This frame has 10 object(s):                                                                                                                                                                                                                                                 \r\n    [32, 4128) 'pkg.i'                                                                                                                                                                                                                                                         \r\n    [4256, 8353) 'rpath.i'                                                                                                                                                                                                                                                     \r\n    [8624, 8632) 'fullpath.i'                                                                                                                                                                                                                                                  \r\n    [8656, 8782) 'slot.i'                                                                                                                                                                                                                                                      \r\n    [8816, 8824) 'slot_hack.i'                                                                                                                                                                                                                                                 \r\n    [8848, 8856) 'slot_len.i'                                                                                                                                                                                                                                                  \r\n    [8880, 12977) 'tmppath.i'                                                                                                                                                                                                                                                  \r\n    [13248, 17345) 'abspath.i'                                                                                                                                                                                                                                                 \r\n    [17616, 17736) 'state' &lt;== Memory access at offset 17345 partially underflows this variable                                                                                                                                                                                \r\n    [17776, 17784) &#039;p&#039; 0x100020cf0350: 00 00 00 00 00 00 00 00[01]f2 f2 f2 f2 f2 f2 f2\r\n  0x100020cf0360: f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2\r\n  0x100020cf0370: f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00\r\n  0x100020cf0380: 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 00 f3\r\n  0x100020cf0390: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x100020cf03a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\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==12240==ABORTING\r\n<\/font><\/pre>\n<p><strong>Affected version:<\/strong><br \/>\nAll versions.<\/p>\n<p><strong>Fixed version:<\/strong><br \/>\n0.61<\/p>\n<p><strong>Commit fix:<\/strong><br \/>\n<a href=\"https:\/\/gitweb.gentoo.org\/proj\/portage-utils.git\/commit\/?id=070f64a84544f74ad633f08c9c07f99a06aea551\">https:\/\/gitweb.gentoo.org\/proj\/portage-utils.git\/commit\/?id=070f64a84544f74ad633f08c9c07f99a06aea551<\/a><\/p>\n<p><strong>Credit:<\/strong><br \/>\nThis bug was discovered by Agostino Sarubbo of Gentoo.<\/p>\n<p><strong>Timeline:<\/strong><br \/>\n2016-02-01: bug discovered<br \/>\n2016-02-01: bug reported to upstream<br \/>\n2016-02-04: upstream release a fix<br \/>\n2016-02-16: blog post about the issue<\/p>\n<p><strong>Note:<\/strong><br \/>\nThis bug was found with <a href=\"http:\/\/lcamtuf.coredump.cx\/afl\">American Fuzzy Lop<\/a>.<br \/>\nAs the commit clearly state, the ability to read directly from a file was removed.<\/p>\n<p><strong>Permalink:<\/strong><\/p>\n<blockquote data-secret=\"1cWz4qzPPB\" class=\"wp-embedded-content\"><p><a href=\"http:\/\/blogs.gentoo.org\/ago\/2016\/02\/16\/portage-utils-stack-based-buffer-overflow-in-qfile-c\/\">portage-utils: stack-based buffer overflow in qfile.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\/2016\/02\/16\/portage-utils-stack-based-buffer-overflow-in-qfile-c\/embed\/#?secret=1cWz4qzPPB\" data-secret=\"1cWz4qzPPB\" width=\"600\" height=\"338\" title=\"&#8220;portage-utils: stack-based buffer overflow in qfile.c&#8221; &#8212; agostino&#039;s blog\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Description: Portage-utils is small and fast portage helper tools written in C. I discovered that a crafted file is able to cause a stack-based buffer overflow. The complete ASan output: ~ # qfile -f qfile-OOB-crash.log ================================================================= ==12240==ERROR: AddressSanitizer: stack-buffer-overflow on &hellip; <a href=\"https:\/\/blogs.gentoo.org\/ago\/2016\/02\/16\/portage-utils-stack-based-buffer-overflow-in-qfile-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":[12,3,10],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2EaBc-5P","_links":{"self":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/361"}],"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=361"}],"version-history":[{"count":5,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/361\/revisions"}],"predecessor-version":[{"id":393,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/361\/revisions\/393"}],"wp:attachment":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/media?parent=361"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/categories?post=361"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/tags?post=361"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}