webp: validate the distance prefix code
authorAndreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Mon, 2 Mar 2015 19:47:57 +0000 (20:47 +0100)
committerAnton Khirnov <anton@khirnov.net>
Thu, 5 Mar 2015 13:49:16 +0000 (14:49 +0100)
commit4f2ee9daeedec636fb4fe953a1e0990a7102d5eb
tree192f60c813f7afe0d17315feb24b538cb033404f
parent66624ed6319cb1a959256fe1a717fec5b748fbfa
webp: validate the distance prefix code

According to the WebP Lossless Bitstream Specification the highest
allowed value for a prefix code is 39.

If prefix_code is too large, the calculated extra_bits has an invalid
value and triggers an assertion in get_bits.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
libavcodec/webp.c