{"id":856,"date":"2016-11-07T18:20:44","date_gmt":"2016-11-07T16:20:44","guid":{"rendered":"http:\/\/blogs.gentoo.org\/ago\/?p=856"},"modified":"2016-12-01T15:55:31","modified_gmt":"2016-12-01T13:55:31","slug":"libdwarf-heap-based-buffer-overflow-in-_dwarf_skim_forms-dwarf_macro5-c","status":"publish","type":"post","link":"https:\/\/blogs.gentoo.org\/ago\/2016\/11\/07\/libdwarf-heap-based-buffer-overflow-in-_dwarf_skim_forms-dwarf_macro5-c\/","title":{"rendered":"libdwarf: heap-based buffer overflow in _dwarf_skim_forms (dwarf_macro5.c)"},"content":{"rendered":"<p><strong>Description<\/strong>:<br \/>\n<a href=\"https:\/\/www.prevanders.net\/dwarf.html\">libdwarf<\/a> is a library to consume and produce DWARF debug information.<\/p>\n<p>A fuzz on an updated version revealed a buffer overflow.<\/p>\n<p>The complete ASan output:<\/p>\n<pre><font size=\"2\"># dwarfdump $FILE\r\n==2437==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62000000fe5b at pc 0x000000462c7c bp 0x7ffea0d4b690 sp 0x7ffea0d4ae40\r\nREAD of size 29 at 0x62000000fe5b thread T0\r\n    #0 0x462c7b in __interceptor_strlen \/var\/tmp\/portage\/sys-devel\/llvm-3.8.1-r2\/work\/llvm-3.8.1.src\/projects\/compiler-rt\/lib\/asan\/asan_interceptors.cc:581\r\n    #1 0x5edea2 in _dwarf_skim_forms \/tmp\/dwarf-20161021\/libdwarf\/dwarf_macro5.c:185:17\r\n    #2 0x5edea2 in _dwarf_get_macro_ops_count_internal \/tmp\/dwarf-20161021\/libdwarf\/dwarf_macro5.c:346\r\n    #3 0x5eb886 in _dwarf_internal_macro_context_by_offset \/tmp\/dwarf-20161021\/libdwarf\/dwarf_macro5.c:1338:11\r\n    #4 0x5eb886 in _dwarf_internal_macro_context \/tmp\/dwarf-20161021\/libdwarf\/dwarf_macro5.c:1201\r\n    #5 0x5ed10e in dwarf_get_macro_context_by_offset \/tmp\/dwarf-20161021\/libdwarf\/dwarf_macro5.c:1467:11\r\n    #6 0x54f7be in print_macros_5style_this_cu \/tmp\/dwarf-20161021\/dwarfdump\/print_macro.c:288:16\r\n    #7 0x514d0f in print_one_die_section \/tmp\/dwarf-20161021\/dwarfdump\/print_die.c:869:21\r\n    #8 0x512262 in print_infos \/tmp\/dwarf-20161021\/dwarfdump\/print_die.c:371:16\r\n    #9 0x4faafa in process_one_file \/tmp\/dwarf-20161021\/dwarfdump\/dwarfdump.c:1371:9\r\n    #10 0x4faafa in main \/tmp\/dwarf-20161021\/dwarfdump\/dwarfdump.c:654\r\n    #11 0x7f74b22e761f in __libc_start_main \/var\/tmp\/portage\/sys-libs\/glibc-2.22-r4\/work\/glibc-2.22\/csu\/libc-start.c:289\r\n    #12 0x419588 in _start (\/usr\/bin\/dwarfdump-asan+0x419588)\r\n\r\n0x62000000fe5b is located 0 bytes to the right of 3547-byte region [0x62000000f080,0x62000000fe5b)\r\nallocated by thread T0 here:\r\n    #0 0x4c0ad8 in malloc \/var\/tmp\/portage\/sys-devel\/llvm-3.8.1-r2\/work\/llvm-3.8.1.src\/projects\/compiler-rt\/lib\/asan\/asan_malloc_linux.cc:52\r\n    #1 0x7f74b33c1206 in __libelf_set_rawdata_wrlock \/tmp\/portage\/dev-libs\/elfutils-0.166\/work\/elfutils-0.166\/libelf\/elf_getdata.c:318\r\n\r\nSUMMARY: AddressSanitizer: heap-buffer-overflow \/var\/tmp\/portage\/sys-devel\/llvm-3.8.1-r2\/work\/llvm-3.8.1.src\/projects\/compiler-rt\/lib\/asan\/asan_interceptors.cc:581 in __interceptor_strlen\r\nShadow bytes around the buggy address:\r\n  0x0c407fff9f70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0c407fff9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0c407fff9f90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0c407fff9fa0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n  0x0c407fff9fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\r\n=&gt;0x0c407fff9fc0: 00 00 00 00 00 00 00 00 00 00 00[03]fa fa fa fa\r\n  0x0c407fff9fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0c407fff9fe0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0c407fff9ff0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0c407fffa000: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa\r\n  0x0c407fffa010: 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==2437==ABORTING\r\n<\/font><\/pre>\n<p><strong>Affected version:<\/strong><br \/>\n20161021<\/p>\n<p><strong>Fixed version:<\/strong><br \/>\n20161124<\/p>\n<p><strong>Commit fix:<\/strong><br \/>\n<a href=\"https:\/\/sourceforge.net\/p\/libdwarf\/code\/ci\/583f8834083b5ef834c497f5b47797e16101a9a6\/\">https:\/\/sourceforge.net\/p\/libdwarf\/code\/ci\/583f8834083b5ef834c497f5b47797e16101a9a6\/<\/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-2016-9275<\/p>\n<p><strong>Reproducer:<\/strong><br \/>\n<a href=\"https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00027-libdwarf-heapoverflow-_dwarf_skim_forms\">https:\/\/github.com\/asarubbo\/poc\/blob\/master\/00027-libdwarf-heapoverflow-_dwarf_skim_forms<\/a><\/p>\n<p><strong>Timeline:<\/strong><br \/>\n2016-11-02: bug discovered and reported to upstream<br \/>\n2016-11-05: upstream released a patch<br \/>\n2016-11-07: blog post about the issue<br \/>\n2016-11-11: CVE assigned<br \/>\n2016-11-24: upstream released 20161124<\/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=\"jixocYtKfm\" class=\"wp-embedded-content\"><p><a href=\"http:\/\/blogs.gentoo.org\/ago\/2016\/11\/07\/libdwarf-heap-based-buffer-overflow-in-_dwarf_skim_forms-dwarf_macro5-c\/\">libdwarf: heap-based buffer overflow in _dwarf_skim_forms (dwarf_macro5.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\/11\/07\/libdwarf-heap-based-buffer-overflow-in-_dwarf_skim_forms-dwarf_macro5-c\/embed\/#?secret=jixocYtKfm\" data-secret=\"jixocYtKfm\" width=\"600\" height=\"338\" title=\"&#8220;libdwarf: heap-based buffer overflow in _dwarf_skim_forms (dwarf_macro5.c)&#8221; &#8212; agostino&#039;s blog\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Description: libdwarf is a library to consume and produce DWARF debug information. A fuzz on an updated version revealed a buffer overflow. The complete ASan output: # dwarfdump $FILE ==2437==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62000000fe5b at pc 0x000000462c7c bp 0x7ffea0d4b690 &hellip; <a href=\"https:\/\/blogs.gentoo.org\/ago\/2016\/11\/07\/libdwarf-heap-based-buffer-overflow-in-_dwarf_skim_forms-dwarf_macro5-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-dO","_links":{"self":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/856"}],"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=856"}],"version-history":[{"count":6,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/856\/revisions"}],"predecessor-version":[{"id":997,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/posts\/856\/revisions\/997"}],"wp:attachment":[{"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/media?parent=856"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/categories?post=856"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.gentoo.org\/ago\/wp-json\/wp\/v2\/tags?post=856"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}