commit faac8e43315dae5818816bcebe52d11777b064b2
author Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> Sat Apr 18 20:09:28 2015 +0200
committer Michael Niedermayer <michaelni@gmx.at> Sun Apr 19 01:27:04 2015 +0200
tree d625bbe4f8fda2a27ebb24662479c825a2c90e35
parent 5be683d687b6b2b697d34274d7ae56af3f047549

alsdec: validate time diff index

If begin is smaller than t, the subtraction 'begin -= t' wraps around,
because begin is unsigned. The same applies for end < t.

This causes segmentation faults.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit faf9fe2c224ea81a98afd53e2f0be0a2e13aeca9)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/alsdec.c

diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index 8a8bff1..0a6be7b 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -1290,8 +1290,16 @@
 
             if (ch[dep].time_diff_sign) {
                 t      = -t;
+                if (t > 0 && begin < t) {
+                    av_log(ctx->avctx, AV_LOG_ERROR, "begin %u smaller than time diff index %d.\n", begin, t);
+                    return AVERROR_INVALIDDATA;
+                }
                 begin -= t;
             } else {
+                if (t > 0 && end < t) {
+                    av_log(ctx->avctx, AV_LOG_ERROR, "end %u smaller than time diff index %d.\n", end, t);
+                    return AVERROR_INVALIDDATA;
+                }
                 end   -= t;
             }