- markus@cvs.openbsd.org 2002/06/05 19:57:12

[authfd.c authfd.h ssh-add.1 ssh-add.c ssh-agent.c]
     ssh-add -x for lock and -X for unlocking the agent.
     todo: encrypt private keys with locked...

ChangeLog

@@ -110,6 +110,10 @@
      [ssh-agent.c]
      copy current request into an extra buffer and just flush this
      request on errors, ok provos@
+   - markus@cvs.openbsd.org 2002/06/05 19:57:12
+     [authfd.c authfd.h ssh-add.1 ssh-add.c ssh-agent.c]
+     ssh-add -x for lock and -X for unlocking the agent.
+     todo: encrypt private keys with locked...
 
 20020604
  - (stevesk) [channels.c] bug #164 patch from YOSHIFUJI Hideaki (changed
@@ -794,4 +798,4 @@
  - (stevesk) entropy.c: typo in debug message
  - (djm) ssh-keygen -i needs seeded RNG; report from markus@
 
-$Id: ChangeLog,v 1.2173 2002/06/06 21:48:57 mouring Exp $
+$Id: ChangeLog,v 1.2174 2002/06/06 21:52:03 mouring Exp $

authfd.c

@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: authfd.c,v 1.49 2002/03/21 22:44:05 rees Exp $");
+RCSID("$OpenBSD: authfd.c,v 1.50 2002/06/05 19:57:12 markus Exp $");
 
 #include <openssl/evp.h>
 
@@ -207,6 +207,26 @@ ssh_close_authentication_connection(AuthenticationConnection *auth)
 	xfree(auth);
 }
 
+/* Lock/unlock agent */
+int
+ssh_lock_agent(AuthenticationConnection *auth, int lock, const char *password)
+{
+	int type;
+	Buffer msg;
+
+	buffer_init(&msg);
+	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
+	buffer_put_cstring(&msg, password);
+
+	if (ssh_request_reply(auth, &msg, &msg) == 0) {
+		buffer_free(&msg);
+		return 0;
+	}
+	type = buffer_get_char(&msg);
+	buffer_free(&msg);
+	return decode_reply(type);
+}
+
 /*
  * Returns the first authentication identity held by the agent.
  */

authfd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: authfd.h,v 1.24 2002/03/21 22:44:05 rees Exp $	*/
+/*	$OpenBSD: authfd.h,v 1.25 2002/06/05 19:57:12 markus Exp $	*/
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -42,6 +42,10 @@
 #define SSH_AGENTC_ADD_SMARTCARD_KEY		20
 #define SSH_AGENTC_REMOVE_SMARTCARD_KEY	        21
 
+/* lock/unlock the agent */
+#define SSH_AGENTC_LOCK				22
+#define SSH_AGENTC_UNLOCK		        23
+
 /* extended failure messages */
 #define SSH2_AGENT_FAILURE			30
 
@@ -67,6 +71,7 @@ Key	*ssh_get_next_identity(AuthenticationConnection *, char **, int);
 int	 ssh_add_identity(AuthenticationConnection *, Key *, const char *);
 int	 ssh_remove_identity(AuthenticationConnection *, Key *);
 int	 ssh_remove_all_identities(AuthenticationConnection *, int);
+int	 ssh_lock_agent(AuthenticationConnection *, int, const char *);
 int	 ssh_update_card(AuthenticationConnection *, int, const char *, const char *);
 
 int

ssh-add.1

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ssh-add.1,v 1.31 2002/06/05 16:35:45 markus Exp $
+.\"	$OpenBSD: ssh-add.1,v 1.32 2002/06/05 19:57:12 markus Exp $
 .\"
 .\"  -*- nroff -*-
 .\"
@@ -45,7 +45,7 @@
 .Nd adds RSA or DSA identities to the authentication agent
 .Sh SYNOPSIS
 .Nm ssh-add
-.Op Fl lLdD
+.Op Fl lLdDxX
 .Op Ar
 .Nm ssh-add
 .Fl s Ar reader
@@ -83,6 +83,10 @@ Lists public key parameters of all identities currently represented by the agent
 Instead of adding the identity, removes the identity from the agent.
 .It Fl D
 Deletes all identities from the agent.
+.It Fl x
+Lock the agent with a password.
+.It Fl X
+Unlock the agent.
 .It Fl s Ar reader
 Add key in smartcard
 .Ar reader .

ssh-add.c

@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh-add.c,v 1.53 2002/03/21 22:44:05 rees Exp $");
+RCSID("$OpenBSD: ssh-add.c,v 1.54 2002/06/05 19:57:12 markus Exp $");
 
 #include <openssl/evp.h>
 
@@ -228,6 +228,34 @@ list_identities(AuthenticationConnection *ac, int do_fp)
 	return 0;
 }
 
+static int
+lock_agent(AuthenticationConnection *ac, int lock)
+{
+	char prompt[100], *p1, *p2;
+	int passok = 1, ret = -1;
+ 
+	strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
+	p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
+	if (lock) {
+		strlcpy(prompt, "Again: ", sizeof prompt);
+		p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
+		if (strcmp(p1, p2) != 0) {
+			fprintf(stderr, "Passwords do not match.\n");
+			passok = 0;
+		}
+		memset(p2, 0, strlen(p2));
+		xfree(p2);
+	}
+	if (passok && ssh_lock_agent(ac, lock, p1)) {
+		fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
+		ret = 0;
+	} else
+		fprintf(stderr, "Failed to %slock agent.\n", lock ? "" : "un");
+	memset(p1, 0, strlen(p1));
+	xfree(p1);
+	return -1;
+}
+
 static int
 do_file(AuthenticationConnection *ac, int deleting, char *file)
 {
@@ -277,7 +305,7 @@ main(int argc, char **argv)
 		fprintf(stderr, "Could not open a connection to your authentication agent.\n");
 		exit(2);
 	}
-	while ((ch = getopt(argc, argv, "lLdDe:s:")) != -1) {
+	while ((ch = getopt(argc, argv, "lLdDxXe:s:")) != -1) {
 		switch (ch) {
 		case 'l':
 		case 'L':
@@ -285,6 +313,12 @@ main(int argc, char **argv)
 				ret = 1;
 			goto done;
 			break;
+		case 'x':
+		case 'X':
+			if (lock_agent(ac, ch == 'x' ? 1 : 0) == -1)
+				ret = 1;
+			goto done;
+			break;
 		case 'd':
 			deleting = 1;
 			break;

ssh-agent.c

@@ -35,7 +35,7 @@
 
 #include "includes.h"
 #include "openbsd-compat/fake-queue.h"
-RCSID("$OpenBSD: ssh-agent.c,v 1.87 2002/06/05 16:48:54 markus Exp $");
+RCSID("$OpenBSD: ssh-agent.c,v 1.88 2002/06/05 19:57:12 markus Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/md5.h>
@@ -95,6 +95,10 @@ pid_t parent_pid = -1;
 char socket_name[1024];
 char socket_dir[1024];
 
+/* locking */
+int locked = 0;
+char *lock_passwd = NULL;
+
 #ifdef HAVE___PROGNAME
 extern char *__progname;
 #else
@@ -442,6 +446,48 @@ send:
 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 }
 
+/* XXX todo: encrypt sensitive data with passphrase */
+static void
+process_lock_agent(SocketEntry *e, int lock)
+{
+	char *passwd;
+	int success = 0;
+
+	passwd = buffer_get_string(&e->request, NULL);
+	if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
+		locked = 0;
+		memset(lock_passwd, 0, strlen(lock_passwd));
+		xfree(lock_passwd);
+		lock_passwd = NULL;
+		success = 1;
+	} else if (!locked && lock) {
+		locked = 1;
+		lock_passwd = xstrdup(passwd);
+		success = 1;
+	}
+	memset(passwd, 0, strlen(passwd));
+	xfree(passwd);
+ 
+	buffer_put_int(&e->output, 1);
+	buffer_put_char(&e->output,
+	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+	return;
+}
+
+static void
+no_identities(SocketEntry *e, u_int type)
+{
+	Buffer msg;
+
+	buffer_init(&msg);
+	buffer_put_char(&msg,
+	    (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
+	    SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
+	buffer_put_int(&msg, 0);
+	buffer_put_int(&e->output, buffer_len(&msg));
+	buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
+	buffer_free(&msg);
+}
 
 #ifdef SMARTCARD
 static void
@@ -557,8 +603,29 @@ process_message(SocketEntry *e)
 	buffer_consume(&e->input, msg_len);
 	type = buffer_get_char(&e->request);
 
+	/* check wheter agent is locked */
+	if (locked && type != SSH_AGENTC_UNLOCK) {
+		buffer_clear(&e->request);
+		switch (type) {
+		case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
+		case SSH2_AGENTC_REQUEST_IDENTITIES:
+			/* send empty lists */
+			no_identities(e, type);
+			break;
+		default:
+			/* send a fail message for all other request types */
+			buffer_put_int(&e->output, 1);
+			buffer_put_char(&e->output, SSH_AGENT_FAILURE);
+		}
+		return;
+	}
+
 	debug("type %d", type);
 	switch (type) {
+	case SSH_AGENTC_LOCK:
+	case SSH_AGENTC_UNLOCK:
+		process_lock_agent(e, type == SSH_AGENTC_LOCK);
+		break;
 	/* ssh1 */
 	case SSH_AGENTC_RSA_CHALLENGE:
 		process_authentication_challenge1(e);