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avcodec/pngdec: Check bit depth for validity

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Fixes: runtime error: shift exponent 132 is too large for 32-bit type 'int'
Fixes: 609/clusterfuzz-testcase-4825202619842560

See 11.2.2 IHDR Image header

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 4279613a26)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2017-02-19 19:12:25 +01:00
parent 367222af32
commit 00a81ed120
1 changed files with 9 additions and 0 deletions
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9
libavcodec/pngdec.c
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@ -557,6 +557,11 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
return AVERROR_INVALIDDATA;
}
s->bit_depth = bytestream2_get_byte(&s->gb);
if (s->bit_depth != 1 && s->bit_depth != 2 && s->bit_depth != 4 &&
s->bit_depth != 8 && s->bit_depth != 16) {
av_log(avctx, AV_LOG_ERROR, "Invalid bit depth\n");
goto error;
}
s->color_type = bytestream2_get_byte(&s->gb);
s->compression_type = bytestream2_get_byte(&s->gb);
s->filter_type = bytestream2_get_byte(&s->gb);
@ -570,6 +575,10 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
s->compression_type, s->filter_type, s->interlace_type);
return 0;
error:
s->cur_w = s->cur_h = s->width = s->height = 0;
s->bit_depth = 8;
return AVERROR_INVALIDDATA;
}
static int decode_phys_chunk(AVCodecContext *avctx, PNGDecContext *s)