libdwarf: heap-based buffer overflow in dwarf_get_aranges_list (dwarf_arange.c)

[Agostino Sarubbo <ago () gentoo org>]

If it is suitable for a CVE please assign one. Thanks.

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
==27460==ERROR: AddressSanitizer: heap-buffer-overflow on address 
0x60600000eff4 at pc 0x00000047349b bp 0x7ffd9feadaf0 sp 0x7ffd9fead2a0
READ of size 2 at 0x60600000eff4 thread T0
    #0 0x47349a in memcpy /var/tmp/portage/sys-devel/llvm-3.8.1-
r2/work/llvm-3.8.1.src/projects/compiler-rt/lib/asan/asan_interceptors.cc:438
    #1 0x56cbe0 in dwarf_get_aranges_list 
/tmp/dwarf-20161021/libdwarf/dwarf_arange.c:118:9
    #2 0x56c0dc in dwarf_get_aranges 
/tmp/dwarf-20161021/libdwarf/dwarf_arange.c:318:11
    #3 0x50f103 in print_aranges 
/tmp/dwarf-20161021/dwarfdump/print_aranges.c:145:12
    #4 0x4fb2bf in process_one_file 
/tmp/dwarf-20161021/dwarfdump/dwarfdump.c:1420:9
    #5 0x4fb2bf in main /tmp/dwarf-20161021/dwarfdump/dwarfdump.c:654
    #6 0x7f2b42a4461f in __libc_start_main /var/tmp/portage/sys-
libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289
    #7 0x419588 in _start (/usr/bin/dwarfdump-asan+0x419588)

0x60600000eff4 is located 0 bytes to the right of 52-byte region 
[0x60600000efc0,0x60600000eff4)
allocated by thread T0 here:
    #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
    #1 0x7f2b43b1e206 in __libelf_set_rawdata_wrlock /tmp/portage/dev-
libs/elfutils-0.166/work/elfutils-0.166/libelf/elf_getdata.c:318

SUMMARY: 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:438 
in memcpy
Shadow bytes around the buggy address:
  0x0c0c7fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9de0: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00
=>0x0c0c7fff9df0: 00 00 00 00 fa fa fa fa 00 00 00 00 00 00[04]fa
  0x0c0c7fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c7fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  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
==27460==ABORTING

Affected version:
20161021

Fixed version:
N/A

Commit fix:
https://sourceforge.net/p/libdwarf/code/ci/583f8834083b5ef834c497f5b47797e16101a9a6/

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

CVE:
N/A

Reproducer:
https://github.com/asarubbo/poc/blob/master/00026-libdwarf-heapoverflow-dwarf_get_aranges_list

Timeline:
2016-11-02: bug discovered and reported to upstream
2016-11-05: upstream released a patch
2016-11-07: blog post about the issue

Note:
This bug was found with American Fuzzy Lop.

Permalink:
https://blogs.gentoo.org/ago/2016/11/07/libdwarf-heap-based-buffer-overflow-in-dwarf_get_aranges_list-dwarf_arange-c