Common code for key exchange algorithm option.

ChangeLog

 2012-07-12  Niels Möller  <nisse@lysator.liu.se>
 
+	* src/algorithms.h (class algorithms_options): New attribute
+	kex_algorithms.
+	* src/algorithms.c (default_kex_algorithms): New function.
+	(lookup_kex_algorithm): New function.
+	(list_kex_algorithms): New function.
+	(algorithms_options): Added --kex-algorithm.
+	(init_algorithms_options): Initialize kex_algorithms.
+	(algorithms_argp_parser): Handle --kex-algorithm, and default
+	value. Use list_kex_algorithms for --list-algorithms.
+
 	* doc/Makefile.in (.nroff.txt): Pass -Tutf8 to groff.
 
 2012-07-10  Niels Möller  <nisse@lysator.liu.se>

src/algorithms.c

@@ -137,6 +137,13 @@ default_hostkey_algorithms(void)
   return make_int_list(2, ATOM_SSH_RSA, ATOM_SSH_DSS, -1);
 }
 
+struct int_list *
+default_kex_algorithms(void)
+{
+  return make_int_list(2, ATOM_DIFFIE_HELLMAN_GROUP14_SHA1,
+		       ATOM_DIFFIE_HELLMAN_GROUP1_SHA1, -1);
+}
+
 static struct int_list *
 prefer_compression_algorithms(struct alist *algorithms)
 {
@@ -302,6 +309,19 @@ lookup_hostkey_algorithm(const char *name)
     return 0;
 }
 
+int
+lookup_kex_algorithm(const char *name)
+{
+  if (strcasecmp_list(name, "diffie-hellman-group1-sha1",
+		       "dh-group1-sha1", "dh-group1", NULL))
+    return ATOM_DIFFIE_HELLMAN_GROUP1_SHA1;
+  else if (strcasecmp_list(name, "diffie-hellman-group14-sha1",
+			    "dh-group14-sha1", "dh-group14", NULL))
+    return ATOM_DIFFIE_HELLMAN_GROUP14_SHA1;
+  else
+    return 0;
+}
+
 /* Return an int list containing the elements of CANDIDATES
  * that have associated values in ALGORITHMS.
  * Returns a non-empty list or NULL. */
@@ -432,9 +452,16 @@ list_hostkey_algorithms(const struct argp_state *state)
   fprintf(state->out_stream, "%s", "Supported hostkey algorithms: ssh-dss, spki, none\n");
 }
 
+void
+list_kex_algorithms(const struct argp_state *state)
+{
+  fprintf(state->out_stream, "%s", "Supported key exchange algorithms: dh-group1.sha1, dh-group14-sha1\n");
+}
+
 
 #define OPT_LIST_ALGORITHMS 0x100
 #define OPT_HOSTKEY_ALGORITHMS 0x101
+#define OPT_KEX_ALGORITHM 0x102
 
 static const struct argp_option
 algorithms_options[] =
@@ -445,7 +472,8 @@ algorithms_options[] =
   { "compression", 'z', "ALGORITHM",
     OPTION_ARG_OPTIONAL, "Default is zlib.", 0 },
   { "mac", 'm', "ALGORITHM", 0, "", 0 },
-  { "hostkey-algorithm", OPT_HOSTKEY_ALGORITHMS, "ALGORITHM", 0, "", 0 }, 
+  { "hostkey-algorithm", OPT_HOSTKEY_ALGORITHMS, "ALGORITHM", 0, "", 0 },
+  { "kex-algorithm", OPT_KEX_ALGORITHM, "ALGORITHM", 0, "", 0 },
   { "list-algorithms", OPT_LIST_ALGORITHMS, NULL, 0,
     "List supported algorithms.", 0 },
   { NULL, 0, NULL, 0, NULL, 0 }  
@@ -461,6 +489,7 @@ init_algorithms_options(struct algorithms_options *self,
   self->mac_algorithms = NULL;
   self->compression_algorithms = NULL;
   self->hostkey_algorithms = NULL;
+  self->kex_algorithms = NULL;
 }
 
 struct algorithms_options *
@@ -490,6 +519,8 @@ algorithms_argp_parser(int key, char *arg, struct argp_state *state)
 	self->compression_algorithms = default_compression_algorithms(self->algorithms);
       if (!self->hostkey_algorithms)
 	self->hostkey_algorithms = default_hostkey_algorithms();
+      if (!self->kex_algorithms)
+	self->kex_algorithms = default_kex_algorithms();
       break;
     case 'c':
       {
@@ -547,7 +578,19 @@ algorithms_argp_parser(int key, char *arg, struct argp_state *state)
 	    argp_error(state, "Unknown hostkey algorithm '%s'.", arg);
 	  }	
 	break;
+      }
 	
+    case OPT_KEX_ALGORITHM:
+      {
+	int algorithm = lookup_kex_algorithm(arg);
+	if (algorithm)
+	  self->kex_algorithms = make_int_list(1, algorithm, -1);
+	else
+	  {
+	    list_kex_algorithms(state);
+	    argp_error(state, "Unknown hostkey algorithm '%s'.", arg);
+	  }	
+	break;
       }
       
     case OPT_LIST_ALGORITHMS:
@@ -555,6 +598,7 @@ algorithms_argp_parser(int key, char *arg, struct argp_state *state)
       list_compression_algorithms(state, self->algorithms);
       list_mac_algorithms(state, self->algorithms);
       list_hostkey_algorithms(state);
+      list_kex_algorithms(state);
       
       if (! (state->flags & ARGP_NO_EXIT))
 	exit (0);

src/algorithms.h

@@ -26,6 +26,7 @@
        (crypto_algorithms object int_list)
        (mac_algorithms object int_list)
        (compression_algorithms object int_list)
+       (kex_algorithms object int_list)
        (hostkey_algorithms object int_list)))
 */
 
@@ -44,6 +45,9 @@ default_compression_algorithms(struct alist *algorithms);
 struct int_list *
 default_hostkey_algorithms(void);
 
+struct int_list *
+default_kex_algorithms(void);
+
 struct int_list *
 filter_algorithms(struct alist *algorithms,
 		  const struct int_list *candidates);
@@ -61,6 +65,9 @@ lookup_compression(struct alist *algorithms, const char *name,
 int
 lookup_hostkey_algorithm(const char *name);
 
+int
+lookup_kex_algorithm(const char *name);
+
 void
 list_crypto_algorithms(const struct argp_state *state,
 		       struct alist *algorithms);
@@ -74,6 +81,9 @@ list_compression_algorithms(const struct argp_state *state,
 void
 list_hostkey_algorithms(const struct argp_state *state);
 
+void
+list_kex_algorithms(const struct argp_state *state);
+
 void init_algorithms_options(struct algorithms_options *self,
 			     struct alist *algorithms);