Author :
Tomas Hoger
Date :
2011-09-11 09:13:45
Hash :83cb6c00 Message :Add explicit LZW decompression stack size limit.
Stack larger than 1<<LZW_MAX_BITS is never needed if prefix table is
constructed correctly. It's even less than that, see e.g.
libarchive code comment for a better size upper bound:
http://code.google.com/p/libarchive/source/browse/trunk/libarchive/archive_read_support_filter_compress.c?r=3635#121
This patch adds explicit stack size limit, enforced when stack is
realloced.
An alternative is to ensure that code < state->prefix[code - 256]
when traversing prefix table. Such check is less efficient and
should not be required if prefix table is constructed correctly in
the first place.
* src/lzw/ftzopen.c (ft_lzwstate_stack_grow): Implement it.
Tomas Hoger