[libav-commits] vc1dec: prevent a crash due missing pred_flag parameter

Vladimir Pantelic git at libav.org
Fri Jan 11 04:58:40 CET 2013


Module: libav
Branch: master
Commit: 7b8c5b263bc680eff5710bee5994de39d47fc15e

Author:    Vladimir Pantelic <vladoman at gmail.com>
Committer: Luca Barbato <lu_zero at gentoo.org>
Date:      Wed Jan  9 17:04:09 2013 +0100

vc1dec: prevent a crash due missing pred_flag parameter

Handle pred_flag parameter not given to get_mvdata_interlaced()

Signed-off-by: Vladimir Pantelic <vladoman at gmail.com>
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

---

 libavcodec/vc1dec.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c
index d5d6884..c29f91c 100644
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@@ -1133,8 +1133,12 @@ static av_always_inline void get_mvdata_interlaced(VC1Context *v, int *dmv_x,
         *dmv_x = get_bits(gb, v->k_x);
         *dmv_y = get_bits(gb, v->k_y);
         if (v->numref) {
-            *pred_flag = *dmv_y & 1;
-            *dmv_y     = (*dmv_y + *pred_flag) >> 1;
+            if (pred_flag) {
+                *pred_flag = *dmv_y & 1;
+                *dmv_y     = (*dmv_y + *pred_flag) >> 1;
+            } else {
+                *dmv_y     = (*dmv_y + (*dmv_y & 1)) >> 1;
+            }
         }
     }
     else {
@@ -1160,7 +1164,7 @@ static av_always_inline void get_mvdata_interlaced(VC1Context *v, int *dmv_x,
             *dmv_y = (sign ^ ((val >> 1) + offs_tab[index1 >> v->numref])) - sign;
         } else
             *dmv_y = 0;
-        if (v->numref)
+        if (v->numref && pred_flag)
             *pred_flag = index1 & 1;
     }
 }



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