| Message ID | 20230111235432.2135-1-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel,1/6] avcodec/eatgq: : Check index increments in tgq_decode_block() | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | success | Make fate finished |
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
On Thu, Jan 12, 2023 at 12:54:27AM +0100, Michael Niedermayer wrote: > 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> > --- > libavcodec/eatgq.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/libavcodec/eatgq.c b/libavcodec/eatgq.c > index 89e9f20880..beb9f4d046 100644 > --- a/libavcodec/eatgq.c > +++ b/libavcodec/eatgq.c > @@ -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, > -- > 2.17.1 Hi Michael, The return value of tgq_decode() is not checked anywhere. Need to add something like: - tgq_decode_block(s, s->block[i], &gb); + if ((ret = tgq_decode_block(s, s->block[i], &gb)) < 0) + return ret; (From earlier attempt at fixing this: https://patchwork.ffmpeg.org/project/ffmpeg/patch/1ab7c3994301a243fc64d59d6a08e3a2b364e411.1666774269.git.pross@xvid.org/) -- Peter (A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
On Sun, Jan 15, 2023 at 01:50:18PM +1100, Peter Ross wrote: > On Thu, Jan 12, 2023 at 12:54:27AM +0100, Michael Niedermayer wrote: > > 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> > > --- > > libavcodec/eatgq.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/libavcodec/eatgq.c b/libavcodec/eatgq.c > > index 89e9f20880..beb9f4d046 100644 > > --- a/libavcodec/eatgq.c > > +++ b/libavcodec/eatgq.c > > @@ -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, > > -- > > 2.17.1 > > Hi Michael, > > The return value of tgq_decode() is not checked anywhere. > > Need to add something like: > > - tgq_decode_block(s, s->block[i], &gb); > + if ((ret = tgq_decode_block(s, s->block[i], &gb)) < 0) > + return ret; will apply with this thx > > (From earlier attempt at fixing this: https://patchwork.ffmpeg.org/project/ffmpeg/patch/1ab7c3994301a243fc64d59d6a08e3a2b364e411.1666774269.git.pross@xvid.org/) > > -- Peter > (A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B) [...]
diff --git a/libavcodec/eatgq.c b/libavcodec/eatgq.c index 89e9f20880..beb9f4d046 100644 --- a/libavcodec/eatgq.c +++ b/libavcodec/eatgq.c @@ -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,
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> --- libavcodec/eatgq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)