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
==27395==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61300000de1c at pc 0x000000528cd3 bp 0x7ffd980a63b0 sp 0x7ffd980a63a8
READ of size 1 at 0x61300000de1c thread T0
#0 0x528cd2 in get_attr_value /tmp/dwarf-20161021/dwarfdump/print_die.c:4978:21
#1 0x51e4a4 in print_attribute /tmp/dwarf-20161021/dwarfdump/print_die.c:3357:13
#2 0x51a651 in print_one_die /tmp/dwarf-20161021/dwarfdump/print_die.c:1458:38
#3 0x51710c in print_die_and_children_internal /tmp/dwarf-20161021/dwarfdump/print_die.c:1047:36
#4 0x517c6b in print_die_and_children_internal /tmp/dwarf-20161021/dwarfdump/print_die.c:1142:13
#5 0x5147cc in print_die_and_children /tmp/dwarf-20161021/dwarfdump/print_die.c:921:5
#6 0x5147cc in print_one_die_section /tmp/dwarf-20161021/dwarfdump/print_die.c:831
#7 0x512262 in print_infos /tmp/dwarf-20161021/dwarfdump/print_die.c:371:16
#8 0x4faafa in process_one_file /tmp/dwarf-20161021/dwarfdump/dwarfdump.c:1371:9
#9 0x4faafa in main /tmp/dwarf-20161021/dwarfdump/dwarfdump.c:654
#10 0x7f883beec61f in __libc_start_main /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289
#11 0x419588 in _start (/usr/bin/dwarfdump-asan+0x419588)
0x61300000de1c is located 0 bytes to the right of 348-byte region [0x61300000dcc0,0x61300000de1c)
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 0x7f883cfc6206 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 /tmp/dwarf-20161021/dwarfdump/print_die.c:4978:21 in get_attr_value
Shadow bytes around the buggy address:
0x0c267fff9b70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c267fff9b80: 00 00 00 00 00 00 00 00 00 00 03 fa fa fa fa fa
0x0c267fff9b90: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
0x0c267fff9ba0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c267fff9bb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c267fff9bc0: 00 00 00[04]fa fa fa fa fa fa fa fa fa fa fa fa
0x0c267fff9bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c267fff9be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c267fff9bf0: 00 00 00 00 00 00 00 00 00 00 00 03 fa fa fa fa
0x0c267fff9c00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c267fff9c10: 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
==27395==ABORTING
Affected version:
20161021
Fixed version:
20161124
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/00025-libdwarf-heapoverflow-get_attr_value
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
2016-11-24: upstream released 20161124
Note:
This bug was found with American Fuzzy Lop.
Permalink:
libdwarf: heap-based buffer overflow in get_attr_value (print_die.c)