oss-security - ytnef: heap-based buffer overflow in PrintTNEF (ytnefprint/main.c)

Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [day] [month] [year] [list]
Date: Wed, 7 Jun 2017 12:52:37 +0000
From: "Agostino Sarubbo" <ago@...too.org>
To: "oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com>
Subject: ytnef: heap-based buffer overflow in PrintTNEF (ytnefprint/main.c)

Not security relevant at all since the crash happens in the command line tool, but I'm sharing it as well.

Description:
ytnef is Yeraze’s TNEF Stream Reader – for winmail.dat files.

The complete ASan output of the issue:

# ytnefprint $FILE
==11928==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000001031 at pc 0x00000049df8d bp 0x7ffd1e1feb20 sp 0x7ffd1e1fe2d0
READ of size 2 at 0x602000001031 thread T0
    #0 0x49df8c in printf_common(void*, char const*, __va_list_tag*) /tmp/portage/sys-libs/compiler-rt-sanitizers-4.0.0/work/compiler-rt-4.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors_format.inc:544
    #1 0x49ea7a in __interceptor_vprintf /tmp/portage/sys-libs/compiler-rt-sanitizers-4.0.0/work/compiler-rt-4.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:1388
    #2 0x49eb37 in printf /tmp/portage/sys-libs/compiler-rt-sanitizers-4.0.0/work/compiler-rt-4.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:1434
    #3 0x509747 in PrintTNEF /tmp/ytnef-1.9.2/ytnefprint/main.c:195:7
    #4 0x50882e in main /tmp/ytnef-1.9.2/ytnefprint/main.c:84:5
    #5 0x7f16830da78f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #6 0x419c38 in _start (/usr/bin/ytnefprint+0x419c38)

0x602000001031 is located 0 bytes to the right of 1-byte region [0x602000001030,0x602000001031)
allocated by thread T0 here:
    #0 0x4cf7e0 in calloc /tmp/portage/sys-libs/compiler-rt-sanitizers-4.0.0/work/compiler-rt-4.0.0.src/lib/asan/asan_malloc_linux.cc:74
    #1 0x7f1683faf8bb in TNEFAttachmentFilename /tmp/ytnef-1.9.2/lib/ytnef.c:752:19
    #2 0x7f1683fc5b47 in TNEFParse /tmp/ytnef-1.9.2/lib/ytnef.c:1184:15
    #3 0x7f1683fc49d3 in TNEFParseFile /tmp/ytnef-1.9.2/lib/ytnef.c:1042:10
    #4 0x508814 in main /tmp/ytnef-1.9.2/ytnefprint/main.c:80:9
    #5 0x7f16830da78f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289

SUMMARY: AddressSanitizer: heap-buffer-overflow /tmp/portage/sys-libs/compiler-rt-sanitizers-4.0.0/work/compiler-rt-4.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors_format.inc:544 in 
printf_common(void*, char const*, __va_list_tag*)
Shadow bytes around the buggy address:
  0x0c047fff81b0: fa fa 00 00 fa fa 04 fa fa fa 00 00 fa fa 00 fa
  0x0c047fff81c0: fa fa 00 00 fa fa 00 fa fa fa 00 00 fa fa 04 fa
  0x0c047fff81d0: fa fa 00 00 fa fa 00 05 fa fa 00 00 fa fa 00 00
  0x0c047fff81e0: fa fa 05 fa fa fa 00 00 fa fa 00 05 fa fa 00 00
  0x0c047fff81f0: fa fa 00 00 fa fa fd fd fa fa fd fd fa fa fd fd
=>0x0c047fff8200: fa fa fd fa fa fa[01]fa fa fa 00 00 fa fa 04 fa
  0x0c047fff8210: fa fa 00 00 fa fa 04 fa fa fa 00 00 fa fa 04 fa
  0x0c047fff8220: fa fa 00 00 fa fa 04 fa fa fa 00 00 fa fa 00 fa
  0x0c047fff8230: fa fa 00 00 fa fa 00 fa fa fa 00 00 fa fa 04 fa
  0x0c047fff8240: fa fa 00 00 fa fa 00 00 fa fa 00 00 fa fa 01 fa
  0x0c047fff8250: fa fa 00 00 fa fa 00 00 fa fa 00 00 fa fa fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==11928==ABORTING
Affected version:
1.9.2

Fixed version:
N/A

Commit fix:
N/A

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

CVE:
N/A

Reproducer:
https://github.com/asarubbo/poc/blob/master/00242-ytnef-heapoverflow-PrintTNEF

Timeline:
2017-03-27: bug discovered and reported to upstream
2017-05-24: blog post about the issue

Note:
This bug was found with American Fuzzy Lop.

Permalink:
https://blogs.gentoo.org/ago/2017/05/24/ytnef-heap-based-buffer-overflow-in-printtnef-ytnefprintmain-c/

--
Agostino Sarubbo
Gentoo Linux Developer
Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.