Reject multiple headers of the same type.

A common application pattern is to call vorbis_synthesis_headerin()
 and count how many times it succeeds.
If you feed it multiple valid comment headers, they will all
 succeed, meaning you can be fooled into think you have a valid
 Vorbis file despite never seeing a setup header.
This patch makes libvorbis reject multiple headers of the same type,
 preventing this from occurring.

svn path=/trunk/vorbis/; revision=19426

diff --git a/lib/info.c b/lib/info.c
index 56ca386..fed4582 100644 (file)
--- a/lib/info.c
+++ b/lib/info.c
@@ -272,7 +272,6 @@ static int _vorbis_unpack_comment(vorbis_comment *vc,oggpack_buffer *opb){
 static int _vorbis_unpack_books(vorbis_info *vi,oggpack_buffer *opb){
   codec_setup_info     *ci=vi->codec_setup;
   int i;
-  if(!ci)return(OV_EFAULT);
 
   /* codebooks */
   ci->books=oggpack_read(opb,8)+1;
@@ -411,6 +410,10 @@ int vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc,ogg_packet *op)
           /* um... we didn't get the initial header */
           return(OV_EBADHEADER);
         }
+        if(vc->vendor!=NULL){
+          /* previously initialized comment header */
+          return(OV_EBADHEADER);
+        }
 
         return(_vorbis_unpack_comment(vc,&opb));
 
@@ -419,6 +422,14 @@ int vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc,ogg_packet *op)
           /* um... we didn;t get the initial header or comments yet */
           return(OV_EBADHEADER);
         }
+        if(vi->codec_setup==NULL){
+          /* improperly initialized vorbis_info */
+          return(OV_EFAULT);
+        }
+        if(((codec_setup_info *)vi->codec_setup)->books>0){
+          /* previously initialized setup header */
+          return(OV_EBADHEADER);
+        }
 
         return(_vorbis_unpack_books(vi,&opb));