audiofile: heap-based buffer overflow in IMA::decodeBlockWAVE (IMA.cpp)

Description:
audiofile is a C-based library for reading and writing audio files in many common formats.

A fuzz on it discovered an heap overflow.

The complete ASan output:

# sfconvert @@ out.mp3 format aiff
==2486==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62f0000286e8 at pc 0x7fc5db36626e bp 0x7ffcecb1cbf0 sp 0x7ffcecb1cbe8                                                                                                                                       
WRITE of size 2 at 0x62f0000286e8 thread T0                                                                                                                                                                                                                                    
    #0 0x7fc5db36626d in IMA::decodeBlockWAVE(unsigned char const*, short*) /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/modules/IMA.cpp:188:13                                                                                                
    #1 0x7fc5db365671 in IMA::decodeBlock(unsigned char const*, short*) /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/modules/IMA.cpp:110:10                                                                                                    
    #2 0x7fc5db361ac9 in BlockCodec::runPull() /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/modules/BlockCodec.cpp:55:3                                                                                                                        
    #3 0x7fc5db39ac20 in RebufferModule::runPull() /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/modules/RebufferModule.cpp:122:3                                                                                                               
    #4 0x7fc5db34b05a in afReadFrames /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/data.cpp:222:14                                                                                                                                             
    #5 0x50bbeb in copyaudiodata /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/sfcommands/sfconvert.c:340:29                                                                                                                                                 
    #6 0x50b050 in main /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/sfcommands/sfconvert.c:248:17                                                                                                                                                          
    #7 0x7fc5da42078f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289                                                                                                                                                     
    #8 0x419f48 in _init (/usr/bin/sfconvert+0x419f48)                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                               
0x62f0000286e8 is located 0 bytes to the right of 49896-byte region [0x62f00001c400,0x62f0000286e8)                                                                                                                                                                            
allocated by thread T0 here:                                                                                                                                                                                                                                                   
    #0 0x4d2d08 in malloc /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:64                                                                                                                                       
    #1 0x7fc5da0b9687 in operator new(unsigned long) (/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/libstdc++.so.6+0xb2687)                                                                                                                                                           
    #2 0x7fc5db34f43c in afGetFrameCount /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/format.cpp:205:41                                                                                                                                        
    #3 0x50bb5c in copyaudiodata /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/sfcommands/sfconvert.c:329:29                                                                                                                                                 
    #4 0x50b050 in main /tmp/portage/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/sfcommands/sfconvert.c:248:17                                                                                                                                                          
    #5 0x7fc5da42078f 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/media-libs/audiofile-0.3.6-r1/work/audiofile-0.3.6/libaudiofile/modules/IMA.cpp:188:13 in IMA::decodeBlockWAVE(unsigned char const*, short*)                                                                      
Shadow bytes around the buggy address:                                                                                                                                                                                                                                         
  0x0c5e7fffd080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                                                                                                                                                                                                              
  0x0c5e7fffd090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c5e7fffd0a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c5e7fffd0b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c5e7fffd0c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c5e7fffd0d0: 00 00 00 00 00 00 00 00 00 00 00 00 00[fa]fa fa
  0x0c5e7fffd0e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c5e7fffd0f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c5e7fffd100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c5e7fffd110: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c5e7fffd120: 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
==2486==ABORTING

Affected version:
0.3.6

Fixed version:
N/A

Commit fix:
N/A

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

CVE:
CVE-2017-6831

Reproducer:
https://github.com/asarubbo/poc/blob/master/00185-audiofile-heapoverflow-IMA-decodeBlockWAVE

Timeline:
2017-02-20: bug discovered and reported to upstream
2017-02-20: blog post about the issue
2017-03-12: CVE assigned

Note:
This bug was found with American Fuzzy Lop.

Permalink:

audiofile: heap-based buffer overflow in IMA::decodeBlockWAVE (IMA.cpp)

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