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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>
(cherry picked from commit e7755b433e)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2023-01-11 23:05:55 +01:00
parent 5cc68bb176
commit 102384cd7d
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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@ -58,7 +58,7 @@ static av_cold int tgq_decode_init(AVCodecContext *avctx)
return 0; 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)
{ {
uint8_t *perm = s->scantable.permutated; uint8_t *perm = s->scantable.permutated;
int i, j, value; int i, j, value;
@ -66,6 +66,8 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
for (i = 1; i < 64;) { for (i = 1; i < 64;) {
switch (show_bits(gb, 3)) { switch (show_bits(gb, 3)) {
case 4: case 4:
if (i >= 63)
return AVERROR_INVALIDDATA;
block[perm[i++]] = 0; block[perm[i++]] = 0;
case 0: case 0:
block[perm[i++]] = 0; block[perm[i++]] = 0;
@ -75,6 +77,8 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
case 1: case 1:
skip_bits(gb, 2); skip_bits(gb, 2);
value = get_bits(gb, 6); value = get_bits(gb, 6);
if (value > 64 - i)
return AVERROR_INVALIDDATA;
for (j = 0; j < value; j++) for (j = 0; j < value; j++)
block[perm[i++]] = 0; block[perm[i++]] = 0;
break; break;
@ -102,6 +106,7 @@ static void tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb
} }
} }
block[0] += 128 << 4; block[0] += 128 << 4;
return 0;
} }
static void tgq_idct_put_mb(TgqContext *s, int16_t (*block)[64], AVFrame *frame, static void tgq_idct_put_mb(TgqContext *s, int16_t (*block)[64], AVFrame *frame,
@ -161,8 +166,11 @@ static int tgq_decode_mb(TgqContext *s, AVFrame *frame, int mb_y, int mb_x)
if (ret < 0) if (ret < 0)
return ret; return ret;
for (i = 0; i < 6; i++) for (i = 0; i < 6; i++) {
tgq_decode_block(s, s->block[i], &gb); 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); tgq_idct_put_mb(s, s->block, frame, mb_x, mb_y);
bytestream2_skip(&s->gb, mode); bytestream2_skip(&s->gb, mode);
} else { } else {