heap-buffer-overflow in function readFromBMP

[fouzhe]

I used Clang 6.0 and AddressSanitizer to build jpeg-encoder, this file can cause heap-buffer-overflow in function readFromBMP when executing this command:

./a.out heap_buffer_overflow_readFromBMP

This is the ASAN information:

=================================================================
==328==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x616000000368 at pc 0x00000049ea5c bp 0x7fff6b99bdb0 sp 0x7fff6b99b560
WRITE of size 24 at 0x616000000368 thread T0
    #0 0x49ea5b in fread /home/fouzhe/llvm/llvm/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:978
    #1 0x51c515 in JpegEncoder::readFromBMP(char const*) /home/fouzhe/my_fuzz/jpeg_encoder/jpeg_encoder.cpp:202:17
    #2 0x51a88b in main /home/fouzhe/my_fuzz/jpeg_encoder/test.cpp:16:14
    #3 0x7f7a716a882f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #4 0x41a638 in _start (/home/fouzhe/my_fuzz/jpeg_encoder/a.out+0x41a638)

0x616000000368 is located 192 bytes to the right of 552-byte region [0x616000000080,0x6160000002a8)
allocated by thread T0 here:
    #0 0x4de868 in __interceptor_malloc /home/fouzhe/llvm/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:88
    #1 0x7f7a716f5cdc  (/lib/x86_64-linux-gnu/libc.so.6+0x6dcdc)

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/fouzhe/llvm/llvm/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:978 in fread
Shadow bytes around the buggy address:
  0x0c2c7fff8010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8050: 00 00 00 00 00 fa fa fa fa fa fa fa fa fa fa fa
=>0x0c2c7fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa[fa]fa fa
  0x0c2c7fff8070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff8090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff80a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2c7fff80b0: 00 00 00 00 00 00 00 00 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
==328==ABORTING

[thejinchao]

Thank you, but this code is just an introduction to the basic JPEG algorithm, and I definitely didn’t consider security too much.