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Code Issues Releases Activity

avcodec/mobiclip: Move quantizer check into setup_qtables()

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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@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-09-24 11:03:43 +02:00
parent 90351b5f11
commit 2f9a3215aa
1 changed files with 14 additions and 7 deletions
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21
libavcodec/mobiclip.c
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@ -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;