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avcodec/mpegvideo_dec: Add NULL pointer checks to MPV_motion_lowres()

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This makes the null pointer checks match mpv_motion_internal()

Fixes: NULL pointer dereference
Fixes: 59671/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG1VIDEO_fuzzer-4993004566609920
Fixes: 59678/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-4893168991338496

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2023-06-08 18:17:46 +02:00
parent d7d3f1af2a
commit adfe003f51
No known key found for this signature in database
GPG Key ID: B18E8928B3948D64
1 changed files with 8 additions and 5 deletions
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13
libavcodec/mpegvideo_dec.c
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@ -885,10 +885,9 @@ static inline void MPV_motion_lowres(MpegEncContext *s,
s->mv[dir][1][0], s->mv[dir][1][1],
block_s, mb_y);
} else {
if (s->picture_structure != s->field_select[dir][0] + 1 &&
s->pict_type != AV_PICTURE_TYPE_B && !s->first_field) {
if ( s->picture_structure != s->field_select[dir][0] + 1 && s->pict_type != AV_PICTURE_TYPE_B && !s->first_field
|| !ref_picture[0]) {
ref_picture = s->current_picture_ptr->f->data;
}
mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,
0, 0, s->field_select[dir][0],
@ -901,8 +900,9 @@ static inline void MPV_motion_lowres(MpegEncContext *s,
for (int i = 0; i < 2; i++) {
uint8_t *const *ref2picture;
if (s->picture_structure == s->field_select[dir][i] + 1 ||
s->pict_type == AV_PICTURE_TYPE_B || s->first_field) {
if ((s->picture_structure == s->field_select[dir][i] + 1 ||
s->pict_type == AV_PICTURE_TYPE_B || s->first_field) &&
ref_picture[0]) {
ref2picture = ref_picture;
} else {
ref2picture = s->current_picture_ptr->f->data;
@ -933,6 +933,9 @@ static inline void MPV_motion_lowres(MpegEncContext *s,
pix_op = s->h264chroma.avg_h264_chroma_pixels_tab;
}
} else {
if (!ref_picture[0]) {
ref_picture = s->current_picture_ptr->f->data;
}
for (int i = 0; i < 2; i++) {
mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,
0, 0, s->picture_structure != i + 1,