[FFmpeg-cvslog] alsdec: validate time diff index

Andreas Cadhalpun git at videolan.org
Sun Apr 19 04:33:44 CEST 2015


ffmpeg | branch: release/2.5 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Sat Apr 18 20:09:28 2015 +0200| [faac8e43315dae5818816bcebe52d11777b064b2] | committer: Michael Niedermayer

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

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=faac8e43315dae5818816bcebe52d11777b064b2
---

 libavcodec/alsdec.c |    8 ++++++++
 1 file changed, 8 insertions(+)

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 @@ static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
 
             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;
             }
 



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