[FFmpeg-cvslog] avcodec/mobiclip: Move quantizer check into setup_qtables()
Michael Niedermayer
git at videolan.org
Fri Sep 25 17:37:38 EEST 2020
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Sep 24 11:03:43 2020 +0200| [2f9a3215aabbc95e43489848aea6205efa43384a] | committer: Michael Niedermayer
avcodec/mobiclip: Move quantizer check into setup_qtables()
Fixes: shift exponent -2 is negative
Fixes: 25683/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MOBICLIP_fuzzer-6434808492982272
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2f9a3215aabbc95e43489848aea6205efa43384a
---
libavcodec/mobiclip.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/libavcodec/mobiclip.c b/libavcodec/mobiclip.c
index 47387fce90..f890cb2599 100644
--- a/libavcodec/mobiclip.c
+++ b/libavcodec/mobiclip.c
@@ -382,11 +382,14 @@ static av_cold int mobiclip_init(AVCodecContext *avctx)
return 0;
}
-static void setup_qtables(AVCodecContext *avctx, int quantizer)
+static int setup_qtables(AVCodecContext *avctx, int quantizer)
{
MobiClipContext *s = avctx->priv_data;
int qx, qy;
+ if (quantizer < 12 || quantizer > 161)
+ return AVERROR_INVALIDDATA;
+
s->quantizer = quantizer;
qx = quantizer % 6;
@@ -400,6 +403,8 @@ static void setup_qtables(AVCodecContext *avctx, int quantizer)
for (int i = 0; i < 20; i++)
s->pre[i] = 9;
+
+ return 0;
}
static void inverse4(int *rs)
@@ -1313,7 +1318,10 @@ static int mobiclip_decode(AVCodecContext *avctx, void *data,
s->moflex = get_bits1(gb);
s->dct_tab_idx = get_bits1(gb);
- setup_qtables(avctx, get_bits(gb, 6));
+ ret = setup_qtables(avctx, get_bits(gb, 6));
+ if (ret < 0)
+ return ret;
+
for (int y = 0; y < avctx->height; y += 16) {
for (int x = 0; x < avctx->width; x += 16) {
ret = decode_macroblock(avctx, frame, x, y, get_bits1(gb));
@@ -1323,10 +1331,6 @@ static int mobiclip_decode(AVCodecContext *avctx, void *data,
}
} else {
MotionXY *motion = s->motion;
- int quantizer = s->quantizer + get_se_golomb(gb);
-
- if (quantizer < 12 || quantizer > 161)
- return AVERROR_INVALIDDATA;
memset(motion, 0, s->motion_size);
@@ -1334,7 +1338,10 @@ static int mobiclip_decode(AVCodecContext *avctx, void *data,
frame->key_frame = 0;
s->dct_tab_idx = 0;
- setup_qtables(avctx, quantizer);
+ ret = setup_qtables(avctx, s->quantizer + get_se_golomb(gb));
+ if (ret < 0)
+ return ret;
+
for (int y = 0; y < avctx->height; y += 16) {
for (int x = 0; x < avctx->width; x += 16) {
int idx;
More information about the ffmpeg-cvslog
mailing list