heap overflow

[XiaoyuHe]

# enviroment
ubuntu 18.04
./jhead poc

# version
3.04

# asan out
=================================================================
==27663==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61d000000a08 at pc 0x562527b27ea8 bp 0x7ffe2a994bb0 sp 0x7ffe2a994ba0
READ of size 1 at 0x61d000000a08 thread T0
    #0 0x562527b27ea7 in ProcessGpsInfo gpsinfo.c:126
    #1 0x562527b194d5 in ProcessExifDir exif.c:866
    #2 0x562527b1a95a in process_EXIF exif.c:1041
    #3 0x562527b06382 in ReadJpegSections jpgfile.c:287
    #4 0x562527b0790e in ReadJpegSections jpgfile.c:126
    #5 0x562527b0790e in ReadJpegFile jpgfile.c:379
    #6 0x562527afd66c in ProcessFile jhead.c:905
    #7 0x562527af8b2e in main jhead.c:1756
    #8 0x7f3c2ea7fbf6 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21bf6)
    #9 0x562527afb279 in _start (/home/fuzz/jhead-3.04/jhead+0x12279)

0x61d000000a08 is located 66 bytes to the right of 2374-byte region [0x61d000000080,0x61d0000009c6)
allocated by thread T0 here:
    #0 0x7f3c2f2cbb40 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb40)
    #1 0x562527b04d6b in ReadJpegSections jpgfile.c:173

SUMMARY: AddressSanitizer: heap-buffer-overflow gpsinfo.c:126 in ProcessGpsInfo
Shadow bytes around the buggy address:
  0x0c3a7fff80f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3a7fff8100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3a7fff8110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3a7fff8120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3a7fff8130: 00 00 00 00 00 00 00 00 06 fa fa fa fa fa fa fa
=>0x0c3a7fff8140: fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3a7fff8150: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3a7fff8160: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3a7fff8170: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3a7fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3a7fff8190: 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
==27663==ABORTING