heap-buffer-overflow on Exiv2::Internal::PngChunk::parseTXTChunk

[legend-issue]

=================================================================
==30669==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61a00001f710 at pc 0x7fa47d77b20b bp 0x7ffd844044b0 sp 0x7ffd84403c58
READ of size 1137 at 0x61a00001f710 thread T0
    #0 0x7fa47d77b20a in __interceptor_strlen (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x7020a)
    #1 0x7fa47d3ce8bf in Exiv2::Internal::PngChunk::parseTXTChunk(Exiv2::DataBuf const&, int, Exiv2::Internal::PngChunk::TxtChunkType) (/home/aflgo/song/exiv2/src/.libs/libexiv2.so.26+0x19a8bf)
    #2 0x7fa47d3ced0a in Exiv2::Internal::PngChunk::decodeTXTChunk(Exiv2::Image*, Exiv2::DataBuf const&, Exiv2::Internal::PngChunk::TxtChunkType) (/home/aflgo/song/exiv2/src/.libs/libexiv2.so.26+0x19ad0a)
    #3 0x7fa47d3cb061 in Exiv2::PngImage::readMetadata() (/home/aflgo/song/exiv2/src/.libs/libexiv2.so.26+0x197061)
    #4 0x419978 in Action::Extract::writeThumbnail() const (/home/aflgo/song/exiv2/bin/.libs/lt-exiv2+0x419978)
    #5 0x422327 in Action::Extract::run(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (/home/aflgo/song/exiv2/bin/.libs/lt-exiv2+0x422327)
    #6 0x406dbd in main (/home/aflgo/song/exiv2/bin/.libs/lt-exiv2+0x406dbd)
    #7 0x7fa47c8f282f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #8 0x407098 in _start (/home/aflgo/song/exiv2/bin/.libs/lt-exiv2+0x407098)

0x61a00001f710 is located 0 bytes to the right of 1168-byte region [0x61a00001f280,0x61a00001f710)
allocated by thread T0 here:
    #0 0x7fa47d7a46b2 in operator new[](unsigned long) (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x996b2)
    #1 0x7fa47d3cae67 in Exiv2::PngImage::readMetadata() (/home/aflgo/song/exiv2/src/.libs/libexiv2.so.26+0x196e67)

SUMMARY: AddressSanitizer: heap-buffer-overflow ??:0 __interceptor_strlen
Shadow bytes around the buggy address:
  0x0c347fffbe90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fffbea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fffbeb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fffbec0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fffbed0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c347fffbee0: 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fffbef0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fffbf00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fffbf10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fffbf20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fffbf30: 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
==30669==ABORTING

command: exiv2 -et [poc]
https://github.com/legend-issue/pocs/blob/master/exiv2/id:000004%2Csig:06%2Csrc:000036%2Cop:havoc%2Crep:128

[fgeek]

Probably duplicate of #302.

[fgeek]

CVE-2018-10999 has been assigned for this issue (not requested by me).

[piponazo]

I could reproduce the issue with the Address sanitizer. I will investigate the issue and try to fix it.

[fgeek]

Great :) 👍

[piponazo]

The bug should be fixed now. Thanks for the report.