[FFmpeg-cvslog] h263dec: Disallow width/height changing with frame threads.

[Michael Niedermayer]

ffmpeg | branch: release/0.8 | Michael Niedermayer <michaelni at gmx.at> | Fri Feb 17 13:35:10 2012 -0800| [4be63587e110c05cda3101abf2e3745d919f3fae] | committer: Reinhard Tartler

h263dec: Disallow width/height changing with frame threads.

Fixes CVE-2011-3937

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 71db86d53b5c6872cea31bf714a1a38ec78feaba)

Conflicts:

	libavcodec/h263dec.c

Signed-off-by: Alex Converse <alex.converse at gmail.com>
Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4be63587e110c05cda3101abf2e3745d919f3fae
---

 libavcodec/h263dec.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index bc6d613..abdaf2b 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -552,8 +552,7 @@ retry:
 #if HAVE_MMX
     if (s->codec_id == CODEC_ID_MPEG4 && s->xvid_build>=0 && avctx->idct_algo == FF_IDCT_AUTO && (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
         avctx->idct_algo= FF_IDCT_XVIDMMX;
-        avctx->coded_width= 0; // force reinit
-//        dsputil_init(&s->dsp, avctx);
+        ff_dct_common_init(s);
         s->picture_number=0;
     }
 #endif
@@ -567,6 +566,12 @@ retry:
         || s->height != avctx->coded_height) {
         /* H.263 could change picture size any time */
         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
+
+        if (HAVE_THREADS && (s->avctx->active_thread_type&FF_THREAD_FRAME)) {
+            av_log_missing_feature(s->avctx, "Width/height/bit depth/chroma idc changing with threads is", 0);
+            return -1;   // width / height changed during parallelized decoding
+        }
+
         s->parse_context.buffer=0;
         MPV_common_end(s);
         s->parse_context= pc;