[FFmpeg-cvslog] oma: correctly mark and decrypt partial packets

[Luca Barbato]

ffmpeg | branch: release/1.1 | Luca Barbato <lu_zero at gentoo.org> | Wed Apr 17 21:19:23 2013 +0200| [d502bd7410570c0a1e566af18097ffe2437937f0] | committer: Luca Barbato

oma: correctly mark and decrypt partial packets

Incomplete crypted files would lead to a read after buffer boundary
otherwise.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
(cherry picked from commit 2219e27b5b17d146e4ab71a3ed86dfc013fb7a93)
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

Conflicts:
	libavformat/omadec.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d502bd7410570c0a1e566af18097ffe2437937f0
---

 libavformat/omadec.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/libavformat/omadec.c b/libavformat/omadec.c
index 07d8b2c..8548fb5 100644
--- a/libavformat/omadec.c
+++ b/libavformat/omadec.c
@@ -393,6 +393,9 @@ static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
     int packet_size = s->streams[0]->codec->block_align;
     int ret = av_get_packet(s->pb, pkt, packet_size);
 
+    if (ret < packet_size)
+        pkt->flags |= AV_PKT_FLAG_CORRUPT;
+
     if (ret < 0)
         return ret;
     if (!ret)
@@ -401,8 +404,13 @@ static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
     pkt->stream_index = 0;
 
     if (oc->encrypted) {
-        /* previous unencrypted block saved in IV for the next packet (CBC mode) */
-        av_des_crypt(&oc->av_des, pkt->data, pkt->data, (packet_size >> 3), oc->iv, 1);
+        /* previous unencrypted block saved in IV for
+         * the next packet (CBC mode) */
+        if (ret == packet_size)
+            av_des_crypt(&oc->av_des, pkt->data, pkt->data,
+                         (packet_size >> 3), oc->iv, 1);
+        else
+            memset(oc->iv, 0, 8);
     }
 
     return ret;