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Allocate pictures with enough padding for jpeg.

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Ensure that jpeg does not use mbs that could require larger padding.
This might have been exploitable.

Originally committed as revision 20566 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2009-11-20 22:14:37 +00:00
parent 9fe0894210
commit 98c82d6910
2 changed files with 6 additions and 3 deletions
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5
libavcodec/mjpegdec.c
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@ -292,9 +292,10 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
(s->h_count[2] << 12) | (s->v_count[2] << 8) |
(s->h_count[3] << 4) | s->v_count[3];
av_log(s->avctx, AV_LOG_DEBUG, "pix fmt id %x\n", pix_fmt_id);
if(!(pix_fmt_id & 0x10101010))
//NOTE we do not allocate pictures large enough for the possible padding of h/v_count being 4
if(!(pix_fmt_id & 0xD0D0D0D0))
pix_fmt_id-= (pix_fmt_id & 0xF0F0F0F0)>>1;
if(!(pix_fmt_id & 0x01010101))
if(!(pix_fmt_id & 0x0D0D0D0D))
pix_fmt_id-= (pix_fmt_id & 0x0F0F0F0F)>>1;
switch(pix_fmt_id){

4
libavcodec/utils.c
View File

@ -126,17 +126,19 @@ void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height){
case PIX_FMT_YUYV422:
case PIX_FMT_UYVY422:
case PIX_FMT_YUV422P:
case PIX_FMT_YUV440P:
case PIX_FMT_YUV444P:
case PIX_FMT_GRAY8:
case PIX_FMT_GRAY16BE:
case PIX_FMT_GRAY16LE:
case PIX_FMT_YUVJ420P:
case PIX_FMT_YUVJ422P:
case PIX_FMT_YUVJ440P:
case PIX_FMT_YUVJ444P:
case PIX_FMT_YUVA420P:
w_align= 16; //FIXME check for non mpeg style codecs and use less alignment
h_align= 16;
if(s->codec_id == CODEC_ID_MPEG2VIDEO)
if(s->codec_id == CODEC_ID_MPEG2VIDEO || s->codec_id == CODEC_ID_MJPEG || s->codec_id == CODEC_ID_AMV || s->codec_id == CODEC_ID_THP)
h_align= 32; // interlaced is rounded up to 2 MBs
break;
case PIX_FMT_YUV411P: