The reader ignores the size of the ASF data object and keeps on

reading even beyond it.
Therefore if the ASF file includes an index object at its end, the
reader will treat the index like data, but of course will fail since
it thinks that the data is corrupted.
When reading an asf file with an index object, ffmpeg will
complain at the end of the file that it read an invalid header.
Patch by Kohn Emil Dan, < emild A cs P technion P ac P il >
Original thead:
Date: Apr 18, 2006 4:11 PM
Subject: [Ffmpeg-devel] Two ASF related bugs and fixes

Originally committed as revision 5857 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/asf.c

@@ -327,6 +327,12 @@ static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
             pos2 = url_ftell(pb);
             url_fskip(pb, gsize - (pos2 - pos1 + 24));
         } else if (!memcmp(&g, &data_header, sizeof(GUID))) {
+            asf->data_object_offset = url_ftell(pb);
+            if (gsize != (uint64_t)-1 && gsize >= 24) {
+                asf->data_object_size = gsize - 24;
+            } else {
+                asf->data_object_size = (uint64_t)-1;
+            }
             break;
         } else if (!memcmp(&g, &comment_header, sizeof(GUID))) {
             int len1, len2, len3, len4, len5;
@@ -552,6 +558,9 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
             /* fail safe */
             url_fskip(pb, ret);
             asf->packet_pos= url_ftell(&s->pb);
+            if (asf->data_object_size != (uint64_t)-1 &&
+                (asf->packet_pos - asf->data_object_offset >= asf->data_object_size))
+                return AVERROR_IO; /* Do not exceed the size of the data object */
             ret = asf_get_packet(s);
             //printf("READ ASF PACKET  %d   r:%d   c:%d\n", ret, asf->packet_size_left, pc++);
             if (ret < 0 || url_feof(pb))

libavformat/asf.h

@@ -32,7 +32,7 @@ typedef struct {
     int ds_data_size;
     int ds_silence_data;
 
-    int packet_pos;
+    int64_t packet_pos;
 
 } ASFStream;
 
@@ -98,6 +98,8 @@ typedef struct {
     ByteIOContext pb;
     /* only for reading */
     uint64_t data_offset; /* begining of the first data packet */
+    uint64_t data_object_offset; /* data object offset (excl. GUID & size)*/
+    uint64_t data_object_size;   /* size of the data object */
 
     ASFMainHeader hdr;
 
@@ -117,7 +119,7 @@ typedef struct {
     int packet_obj_size;
     int packet_time_delta;
     int packet_time_start;
-    int packet_pos;
+    int64_t packet_pos;
 
     int stream_index;