Collected fixes.

g10/ChangeLog

@@ -1,3 +1,18 @@
+2006-11-05  Werner Koch  <wk@g10code.com>
+
+	* gpg.c (main): Remove the default --require-cross-certification.
+	* options.skel: Enable require-cross-certification.
+
+2006-10-31  Werner Koch  <wk@g10code.com>
+
+	* pkclist.c (warn_missing_aes_from_pklist): New.
+	* encode.c (encrypt_filter, encode_crypt): Use it here.
+
+2006-10-27  Werner Koch  <wk@g10code.com>
+
+	* pkclist.c (warn_missing_mdc_from_pklist): New.
+	* encode.c (use_mdc): Use it here.
+
 2006-10-24  Marcus Brinkmann  <marcus@g10code.de>
 
 	* Makefile.am (AM_CFLAGS): Add $(LIBASSUAN_CFLAGS).

g10/encode.c

@@ -147,6 +147,9 @@ use_mdc(PK_LIST pk_list,int algo)
   if (gcry_cipher_get_algo_blklen (algo) != 8)
     return 1;
 
+  if (opt.verbose)
+    warn_missing_mdc_from_pklist (pk_list);
+
   return 0; /* No MDC */
 }
 
@@ -521,6 +524,14 @@ encode_crypt( const char *filename, strlist_t remusr, int use_symkey )
 	      compliance_failure();
 	    }
 	}
+
+        /* In case 3DES has been selected, print a warning if
+           any key does not have a preference for AES.  This
+           should help to indentify why encrypting to several
+           recipients falls back to 3DES. */
+        if (opt.verbose
+            && cfx.dek->algo == CIPHER_ALGO_3DES)
+          warn_missing_aes_from_pklist (pk_list);
     }
     else {
       if(!opt.expert &&
@@ -533,7 +544,7 @@ encode_crypt( const char *filename, strlist_t remusr, int use_symkey )
 
       cfx.dek->algo = opt.def_cipher_algo;
     }
-
+    
     cfx.dek->use_mdc=use_mdc(pk_list,cfx.dek->algo);
 
     /* Only do the is-file-already-compressed check if we are using a
@@ -716,6 +727,14 @@ encrypt_filter( void *opaque, int control,
                      * happen if we do not have any public keys in the list */
 		    efx->cfx.dek->algo = DEFAULT_CIPHER_ALGO;
                 }
+
+                /* In case 3DES has been selected, print a warning if
+                   any key does not have a preference for AES.  This
+                   should help to indentify why encrypting to several
+                   recipients falls back to 3DES. */
+                if (opt.verbose
+                    && efx->cfx.dek->algo == CIPHER_ALGO_3DES)
+                  warn_missing_aes_from_pklist (efx->pk_list);
 	    }
 	    else {
 	      if(!opt.expert &&

g10/gpg.c

@@ -1857,7 +1857,6 @@ main (int argc, char **argv )
     opt.rfc2440_text=1;
     opt.def_sig_expire="0";
     opt.def_cert_expire="0";
-    opt.flags.require_cross_cert = 1;
     set_homedir ( default_homedir () );
 
     /* Check whether we have a config file on the command line.  */

g10/keydb.h

@@ -188,6 +188,8 @@ int  algo_available( preftype_t preftype, int algo,
 int  select_algo_from_prefs( PK_LIST pk_list, int preftype,
 			     int request, const union pref_hint *hint);
 int  select_mdc_from_pklist (PK_LIST pk_list);
+void warn_missing_mdc_from_pklist (PK_LIST pk_list);
+void warn_missing_aes_from_pklist (PK_LIST pk_list);
 
 /*-- skclist.c --*/
 int  random_is_faked (void);

g10/options.skel

@@ -53,6 +53,15 @@
 
 #no-escape-from-lines
 
+# When verifying a signature made from a subkey, ensure that the cross
+# certification "back signature" on the subkey is present and valid.
+# This protects against a subtle attack against subkeys that can sign.
+# Defaults to --no-require-cross-certification.  However for new
+# installations it should be enabled.
+
+require-cross-certification
+
+
 # If you do not use the Latin-1 (ISO-8859-1) charset, you should tell
 # GnuPG which is the native character set.  Please check the man page
 # for supported character sets.  This character set is only used for
@@ -191,22 +200,3 @@ keyserver hkp://subkeys.pgp.net
 # Use your MIME handler to view photos:
 # photo-viewer "metamail -q -d -b -c %T -s 'KeyID 0x%k' -f GnuPG"
 
-# Passphrase agent
-#
-# We support the old experimental passphrase agent protocol as well as
-# the new Assuan based one (currently available in the "newpg" package
-# at ftp.gnupg.org/gcrypt/alpha/aegypten/).  To make use of the agent,
-# you have to run an agent as daemon and use the option
-#
-# use-agent
-# 
-# which tries to use the agent but will fallback to the regular mode
-# if there is a problem connecting to the agent.  The normal way to
-# locate the agent is by looking at the environment variable
-# GPG_AGENT_INFO which should have been set during gpg-agent startup.
-# In certain situations the use of this variable is not possible, thus
-# the option
-# 
-# --gpg-agent-info=<path>:<pid>:1
-#
-# may be used to override it.

g10/pkclist.c

@@ -1328,9 +1328,10 @@ select_algo_from_prefs(PK_LIST pk_list, int preftype, int request,
 	}
 
 #if 0
-	log_debug("pref mask=%08lX%08lX%08lX%08lX%08lX%08lX%08lX%08lX\n",
+	log_debug("pref mask=%08lX%08lX%08lX%08lX%08lX%08lX%08lX%08lX (%s)\n",
 	       (ulong)mask[7], (ulong)mask[6], (ulong)mask[5], (ulong)mask[4],
-	     (ulong)mask[3], (ulong)mask[2], (ulong)mask[1], (ulong)mask[0]);
+               (ulong)mask[3], (ulong)mask[2], (ulong)mask[1], (ulong)mask[0],
+               keystr_from_pk (pkr->pk));
 #endif
 	for(i=0; i < 8; i++ )
 	    bits[i] &= mask[i];
@@ -1423,26 +1424,73 @@ select_algo_from_prefs(PK_LIST pk_list, int preftype, int request,
 }
 
 /*
- * Select the MDC flag from the pk_list.  We can only use MDC if all recipients
- * support this feature 
+ * Select the MDC flag from the pk_list.  We can only use MDC if all
+ * recipients support this feature.
  */
 int
 select_mdc_from_pklist (PK_LIST pk_list)
 {
-    PK_LIST pkr;
+  PK_LIST pkr;
 
-    if( !pk_list )
-	return 0;
-
-    for (pkr = pk_list; pkr; pkr = pkr->next) {
-        int mdc;
-
-        if (pkr->pk->user_id) /* selected by user ID */
-            mdc = pkr->pk->user_id->flags.mdc;
-        else
-            mdc = pkr->pk->mdc_feature;
-        if (!mdc)
-            return 0; /* at least one recipient does not support it */
+  if ( !pk_list )
+    return 0;
+  
+  for (pkr = pk_list; pkr; pkr = pkr->next) 
+    {
+      int mdc;
+      
+      if (pkr->pk->user_id) /* selected by user ID */
+        mdc = pkr->pk->user_id->flags.mdc;
+      else
+        mdc = pkr->pk->mdc_feature;
+      if (!mdc)
+        return 0;  /* At least one recipient does not support it. */
+    }
+  return 1; /* Can be used. */
+}
+
+
+/* Print a warning for all keys in PK_LIST missing the MDC feature. */
+void
+warn_missing_mdc_from_pklist (PK_LIST pk_list)
+{
+  PK_LIST pkr;
+  
+  for (pkr = pk_list; pkr; pkr = pkr->next) 
+    {
+      int mdc;
+
+      if (pkr->pk->user_id) /* selected by user ID */
+        mdc = pkr->pk->user_id->flags.mdc;
+      else
+        mdc = pkr->pk->mdc_feature;
+      if (!mdc)
+        log_info (_("Note: key %s has no %s feature\n"),
+                  keystr_from_pk (pkr->pk), "MDC");
+    }
+}
+
+void
+warn_missing_aes_from_pklist (PK_LIST pk_list)
+{
+  PK_LIST pkr;
+ 
+  for (pkr = pk_list; pkr; pkr = pkr->next) 
+    {
+      const prefitem_t *prefs;
+      int i;
+      int gotit = 0;
+
+      prefs = pkr->pk->user_id? pkr->pk->user_id->prefs : pkr->pk->prefs;
+      if (prefs)
+        {
+          for (i=0; !gotit && prefs[i].type; i++ )
+            if (prefs[i].type == PREFTYPE_SYM 
+                && prefs[i].value == CIPHER_ALGO_AES)
+              gotit++;
+	}
+      if (!gotit)
+        log_info (_("Note: key %s has no preference for %s\n"),
+                  keystr_from_pk (pkr->pk), "AES");
     }
-    return 1; /* can be used */
 }