avcodec/shorten: Move buffer allocation and offset init to end of read_header()

They are time consuming operations, performing them after the other checks
improves the speed with damaged input dramatically.

Fixes: Timeout
Fixes: 2928/clusterfuzz-testcase-4992812120539136

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 380659604f2692b625928a3a76a1c046f473c9f6)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2017-09-10 21:10:16 +02:00
parent 33e67eb80c
commit 19045efd05

View File

@ -453,12 +453,6 @@ static int read_header(ShortenContext *s)
}
s->nwrap = FFMAX(NWRAP, maxnlpc);
if ((ret = allocate_buffers(s)) < 0)
return ret;
if ((ret = init_offset(s)) < 0)
return ret;
if (s->version > 1)
s->lpcqoffset = V2LPCQOFFSET;
@ -494,6 +488,13 @@ static int read_header(ShortenContext *s)
}
end:
if ((ret = allocate_buffers(s)) < 0)
return ret;
if ((ret = init_offset(s)) < 0)
return ret;
s->cur_chan = 0;
s->bitshift = 0;