binutils: heap-based buffer overflow in parse_die (dwarf1.c)

["Agostino Sarubbo" <ago () gentoo org>]

Description:
binutils is a set of tools necessary to build programs.

The complete ASan output of the issue:

# nm -A -a -l -S -s --special-syms --synthetic --with-symbol-versions -D $FILE
==26890==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6130000006d3 at pc 0x000000472115 bp 0x7ffdb7d8a0d0 
sp 0x7ffdb7d89880                                                                         
READ of size 298 at 0x6130000006d3 thread T0                                                                            
                                                                                          
    #0 0x472114 in __interceptor_strlen 
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-5.0.0/work/compiler-rt-5.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:302
                      
    #1 0x68fea5 in parse_die /var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/dwarf1.c:254:12                 
                                                                                          
    #2 0x68ddda in _bfd_dwarf1_find_nearest_line 
/var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/dwarf1.c:521:13                                              
                                         
    #3 0x5f2f00 in _bfd_elf_find_nearest_line /var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/elf.c:8659:10  
                                                                                          
    #4 0x517755 in print_symbol /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1004:12            
                                                                                          
    #5 0x514e4d in print_symbols /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1084:7            
                                                                                          
    #6 0x514e4d in display_rel_file /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1200           
                                                                                          
    #7 0x510976 in display_file /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1318:7             
                                                                                          
    #8 0x50f4ce in main /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1792:12                    
                                                                                          
    #9 0x7f3dea34e680 in __libc_start_main 
/var/tmp/portage/sys-libs/glibc-2.23-r4/work/glibc-2.23/csu/../csu/libc-start.c:289                                     
                                               
    #10 0x41a638 in chmod (/usr/x86_64-pc-linux-gnu/binutils-bin/git/nm+0x41a638)                                       
                                                                                          
                                                                                                                        
                                                                                          
0x6130000006d3 is located 0 bytes to the right of 339-byte region [0x613000000580,0x6130000006d3)                       
                                                                                          
allocated by thread T0 here:                                                                                            
                                                                                          
    #0 0x4d8828 in malloc 
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-5.0.0/work/compiler-rt-5.0.0.src/lib/asan/asan_malloc_linux.cc:67      
                                                                
    #1 0x53f138 in bfd_malloc /var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/libbfd.c:193:9
    #2 0x799bc8 in bfd_get_full_section_contents 
/var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/compress.c:248:21
    #3 0x7b8797 in bfd_simple_get_relocated_section_contents 
/var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/simple.c:193:12
    #4 0x68e3b1 in _bfd_dwarf1_find_nearest_line 
/var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/dwarf1.c:490:4
    #5 0x5f2f00 in _bfd_elf_find_nearest_line /var/tmp/portage/sys-devel/binutils-9999/work/binutils/bfd/elf.c:8659:10
    #6 0x517755 in print_symbol /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1004:12
    #7 0x514e4d in print_symbols /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1084:7
    #8 0x514e4d in display_rel_file /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1200
    #9 0x510976 in display_file /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1318:7
    #10 0x50f4ce in main /var/tmp/portage/sys-devel/binutils-9999/work/binutils/binutils/nm.c:1792:12
    #11 0x7f3dea34e680 in __libc_start_main 
/var/tmp/portage/sys-libs/glibc-2.23-r4/work/glibc-2.23/csu/../csu/libc-start.c:289

SUMMARY: AddressSanitizer: heap-buffer-overflow 
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-5.0.0/work/compiler-rt-5.0.0.src/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:302
 in 
__interceptor_strlen
Shadow bytes around the buggy address:
  0x0c267fff8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c267fff8090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c267fff80a0: 00 00 00 04 fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c267fff80b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c267fff80c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c267fff80d0: 00 00 00 00 00 00 00 00 00 00[03]fa fa fa fa fa
  0x0c267fff80e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c267fff80f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c267fff8100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c267fff8110: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c267fff8120: 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
  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
==26890==ABORTING

Affected version:
2.29.51.20170924 and maybe past releases

Fixed version:
N/A

Commit fix:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1da5c9a485f3dcac4c45e96ef4b7dae5948314b5

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

CVE:
CVE-2017-15020

Reproducer:
https://github.com/asarubbo/poc/blob/master/00376-binutils-heapoverflow-parse_die

Timeline:
2017-09-25: bug discovered and reported to upstream
2017-09-25: upstream released a patch
2017-10-03: blog post about the issue
2017-10-04: CVE assigned

Note:
This bug was found with American Fuzzy Lop.
This bug was identified with bare metal servers donated by Packet. This work is also supported by the Core
Infrastructure Initiative.

Permalink:
https://blogs.gentoo.org/ago/2017/10/03/binutils-heap-based-buffer-overflow-in-parse_die-dwarf1-c/

--
Agostino Sarubbo
Gentoo Linux Developer