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avcodec/eatgq: : Check index increments in tgq_decode_block() 

Fixes: out of array access
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_EATGQ_fuzzer-6743211456724992

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2023-01-11 23:05:55 +01:00
parent 2378cbe36b
commit e7755b433e
No known key found for this signature in database
GPG Key ID: B18E8928B3948D64
1 changed files with 11 additions and 3 deletions
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14
libavcodec/eatgq.c
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@ -56,7 +56,7 @@ static av_cold int tgq_decode_init(AVCodecContext *avctx)
return 0;
}
static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb)
static int tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb)
{
const uint8_t *scantable = ff_zigzag_direct;
int i, j, value;
@ -64,6 +64,8 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
for (i = 1; i < 64;) {
switch (show_bits(gb, 3)) {
case 4:
if (i >= 63)
return AVERROR_INVALIDDATA;
block[scantable[i++]] = 0;
case 0:
block[scantable[i++]] = 0;
@ -73,6 +75,8 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
case 1:
skip_bits(gb, 2);
value = get_bits(gb, 6);
if (value > 64 - i)
return AVERROR_INVALIDDATA;
for (j = 0; j < value; j++)
block[scantable[i++]] = 0;
break;
@ -100,6 +104,7 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
}
}
block[0] += 128 << 4;
return 0;
}
static void tgq_idct_put_mb(TgqContext *s, int16_t (*block)[64], AVFrame *frame,
@ -160,8 +165,11 @@ static int tgq_decode_mb(TgqContext *s, GetByteContext *gbyte,
if (ret < 0)
return ret;
for (i = 0; i < 6; i++)
tgq_decode_block(s, s->block[i], &gb);
for (i = 0; i < 6; i++) {
int ret = tgq_decode_block(s, s->block[i], &gb);
if (ret < 0)
return ret;
}
tgq_idct_put_mb(s, s->block, frame, mb_x, mb_y);
bytestream2_skip(gbyte, mode);
} else {