[svn] GnuPG - r4426 - trunk/g10

[svn author wk]

Author: wk
Date: 2007-02-04 18:23:00 +0100 (Sun, 04 Feb 2007)
New Revision: 4426

Modified:
   trunk/g10/ChangeLog
   trunk/g10/parse-packet.c
Log:
Fix for Debian bug 402592


Modified: trunk/g10/ChangeLog
===================================================================
--- trunk/g10/ChangeLog	2007-02-04 17:20:24 UTC (rev 4425)
+++ trunk/g10/ChangeLog	2007-02-04 17:23:00 UTC (rev 4426)
@@ -1,3 +1,8 @@
+2007-02-04  Werner Koch  <wk at g10code.com>
+
+	* parse-packet.c (parse_signature): Limit bytes read for an
+	unknown alogorithm.  Fixes Debian bug#402592.
+
 2007-01-31  Werner Koch  <wk at g10code.com>
 
 	* verify.c (verify_signatures): Do no dereference a NULL afx.

Modified: trunk/g10/parse-packet.c
===================================================================
--- trunk/g10/parse-packet.c	2007-02-04 17:20:24 UTC (rev 4425)
+++ trunk/g10/parse-packet.c	2007-02-04 17:23:00 UTC (rev 4426)
@@ -1494,9 +1494,19 @@
 	unknown_pubkey_warning( sig->pubkey_algo );
 	/* We store the plain material in data[0], so that we are able
 	 * to write it back with build_packet() */
-	sig->data[0]= gcry_mpi_set_opaque (NULL, read_rest(inp, pktlen, 0),
-                                           pktlen*8 );
-	pktlen = 0;
+        if (pktlen > (5 * MAX_EXTERN_MPI_BITS/8))
+          {
+            /* However we include a limit to avoid too trivial DoS
+               attacks by having gpg allocate too much memory.  */
+	    log_error ("signature packet: too much data\n");
+	    rc = G10ERR_INVALID_PACKET;
+          }
+        else
+          {
+            sig->data[0]= gcry_mpi_set_opaque (NULL, read_rest(inp, pktlen, 0),
+                                               pktlen*8 );
+            pktlen = 0;
+          }
     }
     else {
 	for( i=0; i < ndata; i++ ) {