[FFmpeg-cvslog] svq1dec: check that the reference frame has the same dimensions as the current one

[Anton Khirnov]

ffmpeg | branch: release/1.1 | Anton Khirnov <anton at khirnov.net> | Mon Apr  8 22:12:12 2013 +0200| [43039f9386d2d81eb39a9737b1c622bb83af36f8] | committer: Reinhard Tartler

svq1dec: check that the reference frame has the same dimensions as the current one

They can be different if the last keyframe failed to decode correctly.
Fixes possible invalid reads in such a case.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable at libav.org
(cherry picked from commit b1bb8fb860b47e90dd67f0c5740698128fc82dcc)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=43039f9386d2d81eb39a9737b1c622bb83af36f8
---

 libavcodec/svq1dec.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/svq1dec.c b/libavcodec/svq1dec.c
index 5156042..19ff8d6 100644
--- a/libavcodec/svq1dec.c
+++ b/libavcodec/svq1dec.c
@@ -692,7 +692,8 @@ static int svq1_decode_frame(AVCodecContext *avctx, void *data,
         } else {
             /* delta frame */
             uint8_t *previous = s->prev->data[i];
-            if (!previous) {
+            if (!previous ||
+                s->prev->width != s->width || s->prev->height != s->height) {
                 av_log(avctx, AV_LOG_ERROR, "Missing reference frame.\n");
                 result = AVERROR_INVALIDDATA;
                 goto err;