From c23ef5b345887c3cd7c4a431881c4e8316e24426 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 11 Jan 2023 23:05:55 +0100 Subject: [PATCH] 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 (cherry picked from commit e7755b433e913e32bb061f17d5ecfcbcfef995b7) Signed-off-by: Michael Niedermayer --- libavcodec/eatgq.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/libavcodec/eatgq.c b/libavcodec/eatgq.c index 1308c07cff..46bf226f6a 100644 --- a/libavcodec/eatgq.c +++ b/libavcodec/eatgq.c @@ -58,7 +58,7 @@ 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) { uint8_t *perm = s->scantable.permutated; 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;) { switch (show_bits(gb, 3)) { case 4: + if (i >= 63) + return AVERROR_INVALIDDATA; block[perm[i++]] = 0; case 0: block[perm[i++]] = 0; @@ -75,6 +77,8 @@ 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[perm[i++]] = 0; break; @@ -102,6 +106,7 @@ 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, @@ -161,8 +166,11 @@ static int tgq_decode_mb(TgqContext *s, AVFrame *frame, int mb_y, int mb_x) 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(&s->gb, mode); } else {