CVE-2009-1759

http://sourceforge.net/tracker/?func=detail&aid=2782875&group_id=202532&atid=981959

Index: bencode.h
===================================================================
--- bencode.h	(revision 301)
+++ bencode.h	(revision 302)
@@ -25,7 +25,7 @@
 size_t decode_list(const char *b,size_t len,const char *keylist);
 size_t decode_rev(const char *b,size_t len,const char *keylist);
 size_t decode_query(const char *b,size_t len,const char *keylist,const char **ps,size_t *pi,int64_t *pl,int method);
-size_t decode_list2path(const char *b, size_t n, char *pathname);
+size_t decode_list2path(const char *b, size_t n, char *pathname, size_t maxlen);
 size_t bencode_buf(const char *str,size_t len,FILE *fp);
 size_t bencode_str(const char *str, FILE *fp);
 size_t bencode_int(const uint64_t integer, FILE *fp);
Index: bencode.cpp
===================================================================
--- bencode.cpp	(revision 301)
+++ bencode.cpp	(revision 302)
@@ -233,22 +233,28 @@
   return bencode_end_dict_list(fp);
 }
 
-size_t decode_list2path(const char *b, size_t n, char *pathname)
+size_t decode_list2path(const char *b, size_t n, char *pathname, size_t maxlen)
 {
   const char *pb = b;
   const char *s = (char *) 0;
+  const char *endmax = pathname + maxlen - 1;
   size_t r,q;
 
   if( 'l' != *pb ) return 0;
   pb++;
   n--;
   if( !n ) return 0;
-  for(; n;){
+  while( n && pathname < endmax ){
     if(!(r = buf_str(pb, n, &s, &q)) ) return 0;
+    if( q >= maxlen ) return 0;
     memcpy(pathname, s, q);
     pathname += q;
-    pb += r; n -= r; 
-    if( 'e' != *pb ){*pathname = PATH_SP, pathname++;} else break;
+    maxlen -= q;
+    pb += r;
+    n -= r; 
+    if( 'e' == *pb ) break;
+    if( pathname >= endmax ) return 0;
+    *pathname++ = PATH_SP;
   }
   *pathname = '\0';
   return (pb - b + 1);
Index: btfiles.cpp
===================================================================
--- btfiles.cpp	(revision 301)
+++ btfiles.cpp	(revision 302)
@@ -471,6 +471,8 @@
     BTFILE *pbf_last = (BTFILE*) 0; 
     BTFILE *pbf = (BTFILE*) 0;
     size_t dl;
+    unsigned long nfiles = 0;
+
     if( decode_query(metabuf,metabuf_len,"info|length",
                     (const char**) 0,(size_t*) 0,(int64_t*) 0,QUERY_LONG) )
       return -1;
@@ -524,12 +526,18 @@
 #ifndef WINDOWS
       if( !pbf ) return -1;
 #endif
+      nfiles++;
       pbf->bf_length = t;
       m_total_files_length += t;
       r = decode_query(p, dl, "path", (const char **)0, &n, (int64_t*)0,
                        QUERY_POS);
-      if( !r ) return -1;
-      if(!decode_list2path(p + r, n, path)) return -1;
+      if( !r || !decode_list2path(p + r, n, path, sizeof(path)) ){
+        CONSOLE.Warning(1,
+          "error, invalid path in torrent data for file %lu at offset %llu",
+          nfiles, m_total_files_length - t);
+        delete pbf;
+        return -1;
+      }
 
       int f_conv;
       char *tmpfn = new char[strlen(path)*2+5];