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Code Issues Releases Activity

mpegvideo: Make the table reallocation more robust.

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This fixes out of array writes after resolution changes
No FFmpeg releases are known to be affected by this

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-03-28 23:46:13 +01:00
parent 0fb9f77a39
commit 6ae03353de
2 changed files with 14 additions and 2 deletions
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13
libavcodec/mpegvideo.c
View File

@ -294,6 +294,9 @@ static void free_picture_tables(Picture *pic)
{
int i;
pic->alloc_mb_width =
pic->alloc_mb_height = 0;
av_buffer_unref(&pic->mb_var_buf);
av_buffer_unref(&pic->mc_mb_var_buf);
av_buffer_unref(&pic->mb_mean_buf);
@ -343,6 +346,9 @@ static int alloc_picture_tables(MpegEncContext *s, Picture *pic)
}
}
pic->alloc_mb_width = s->mb_width;
pic->alloc_mb_height = s->mb_height;
return 0;
}
@ -380,8 +386,8 @@ int ff_alloc_picture(MpegEncContext *s, Picture *pic, int shared)
int i, ret;
if (pic->qscale_table_buf)
if (pic->mbskip_table_buf->size < s->mb_stride * s->mb_height + 2 ||
pic->qscale_table_buf->size < s->mb_stride * (s->mb_height + 1) + 1 + s->mb_stride)
if ( pic->alloc_mb_width != s->mb_width
|| pic->alloc_mb_height != s->mb_height)
free_picture_tables(pic);
if (shared) {
@ -490,6 +496,9 @@ do {\
dst->ref_index[i] = src->ref_index[i];
}
dst->alloc_mb_width = src->alloc_mb_width;
dst->alloc_mb_height = src->alloc_mb_height;
return 0;
}

3
libavcodec/mpegvideo.h
View File

@ -119,6 +119,9 @@ typedef struct Picture{
AVBufferRef *mc_mb_var_buf;
uint16_t *mc_mb_var; ///< Table for motion compensated MB variances
int alloc_mb_width; ///< mb_width used to allocate tables
int alloc_mb_height; ///< mb_height used to allocate tables
AVBufferRef *mb_mean_buf;
uint8_t *mb_mean; ///< Table for MB luminance