[FFmpeg-cvslog] avcodec/mpegvideo_dec: Add NULL pointer checks to MPV_motion_lowres()
Michael Niedermayer
git at videolan.org
Sun Jun 18 15:30:04 EEST 2023
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Jun 8 18:17:46 2023 +0200| [adfe003f518dac098ba9cdabcd6158fa55383710] | committer: Michael Niedermayer
avcodec/mpegvideo_dec: Add NULL pointer checks to MPV_motion_lowres()
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 at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=adfe003f518dac098ba9cdabcd6158fa55383710
---
libavcodec/mpegvideo_dec.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/libavcodec/mpegvideo_dec.c b/libavcodec/mpegvideo_dec.c
index c87ca77ae6..fcca147cd6 100644
--- a/libavcodec/mpegvideo_dec.c
+++ b/libavcodec/mpegvideo_dec.c
@@ -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,
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