enable DES in SSH-1 clients only

5 files changed, 26 insertions, 17 deletions

diff --git a/usr.bin/ssh/cipher.c b/usr.bin/ssh/cipher.c
index 8d6d1c35a7e..0bfbc23c873 100644
--- a/usr.bin/ssh/cipher.c
+++ b/usr.bin/ssh/cipher.c
@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: cipher.c,v 1.33 2000/10/11 20:45:21 markus Exp $");
+RCSID("$OpenBSD: cipher.c,v 1.34 2000/10/12 09:59:18 markus Exp $");
 
 #include "ssh.h"
 #include "xmalloc.h"
@@ -62,6 +62,12 @@ none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
 void
 des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
 {
+	static int dowarn = 1;
+	if (dowarn) {
+		error("Warning: use of DES is strongly discouraged "
+		    "due to cryptographic weaknesses");
+		dowarn = 0;
+	}
 	des_set_key((void *)key, cc->u.des.key);
 }
 void
@@ -301,6 +307,10 @@ Cipher ciphers[] = {
 		SSH_CIPHER_NONE, 8, 0,
 		none_setkey, none_setiv,
 		none_crypt, none_crypt },
+	{ "des",
+		SSH_CIPHER_DES, 8, 8,
+		des_ssh1_setkey, des_ssh1_setiv,
+		des_ssh1_encrypt, des_ssh1_decrypt },
 	{ "3des",
 		SSH_CIPHER_3DES, 8, 16,
 		des3_ssh1_setkey, des3_setiv,
@@ -332,13 +342,13 @@ Cipher ciphers[] = {
 /*--*/
 
 unsigned int
-cipher_mask1()
+cipher_mask_ssh1(int client)
 {
 	unsigned int mask = 0;
-	Cipher *c;
-	for (c = ciphers; c->name != NULL; c++) {
-		if (c->number > SSH_CIPHER_NONE)
-			mask |= 1 << c->number;
+	mask |= 1 << SSH_CIPHER_3DES;           /* Mandatory */
+	mask |= 1 << SSH_CIPHER_BLOWFISH;
+	if (client) {
+		mask |= 1 << SSH_CIPHER_DES;
 	}
 	return mask;
 }
@@ -347,9 +357,6 @@ Cipher *
 cipher_by_name(const char *name)
 {
 	Cipher *c;
-	if (strcmp(name, "des") == 0)
-		error("Warning: use of DES is strongly discouraged "
-		    "due to cryptographic weaknesses");
 	for (c = ciphers; c->name != NULL; c++)
 		if (strcasecmp(c->name, name) == 0)
 			return c;
diff --git a/usr.bin/ssh/cipher.h b/usr.bin/ssh/cipher.h
index 1140285856a..e342abf77e4 100644
--- a/usr.bin/ssh/cipher.h
+++ b/usr.bin/ssh/cipher.h
@@ -32,7 +32,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-/* RCSID("$OpenBSD: cipher.h,v 1.20 2000/10/11 20:27:23 markus Exp $"); */
+/* RCSID("$OpenBSD: cipher.h,v 1.21 2000/10/12 09:59:18 markus Exp $"); */
 
 #ifndef CIPHER_H
 #define CIPHER_H
@@ -97,7 +97,7 @@ struct Cipher {
 	void	(*decrypt)(CipherContext *, u_char *, const u_char *, u_int);
 };
 
-unsigned int cipher_mask1();
+unsigned int cipher_mask_ssh1(int client);
 Cipher *cipher_by_name(const char *name);
 Cipher *cipher_by_number(int id);
 int cipher_number(const char *name);
diff --git a/usr.bin/ssh/sshconnect1.c b/usr.bin/ssh/sshconnect1.c
index 83994f51813..ce560791cea 100644
--- a/usr.bin/ssh/sshconnect1.c
+++ b/usr.bin/ssh/sshconnect1.c
@@ -13,7 +13,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect1.c,v 1.7 2000/10/11 20:27:24 markus Exp $");
+RCSID("$OpenBSD: sshconnect1.c,v 1.8 2000/10/12 09:59:19 markus Exp $");
 
 #include <openssl/bn.h>
 #include <openssl/dsa.h>
@@ -838,7 +838,7 @@ ssh_kex(char *host, struct sockaddr *hostaddr)
 		    cipher_name(ssh_cipher_default));
 		options.cipher = ssh_cipher_default;
 	} else if (options.cipher == SSH_CIPHER_NOT_SET) {
-		if (cipher_mask1() & supported_ciphers & (1 << ssh_cipher_default))
+		if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default))
 			options.cipher = ssh_cipher_default;
 	}
 	/* Check that the selected cipher is supported. */
diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c
index 0785548a486..ca459f62c35 100644
--- a/usr.bin/ssh/sshconnect2.c
+++ b/usr.bin/ssh/sshconnect2.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect2.c,v 1.24 2000/10/11 20:27:24 markus Exp $");
+RCSID("$OpenBSD: sshconnect2.c,v 1.25 2000/10/12 09:59:19 markus Exp $");
 
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
@@ -80,6 +80,8 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 			options.ciphers = "3des-cbc";
 		} else if (options.cipher == SSH_CIPHER_BLOWFISH) {
 			options.ciphers = "blowfish-cbc";
+		} else if (options.cipher == SSH_CIPHER_DES) {
+			fatal("cipher DES not supported for protocol version 2");
 		}
 	}
 	if (options.ciphers != NULL) {
diff --git a/usr.bin/ssh/sshd.c b/usr.bin/ssh/sshd.c
index 664d00223f0..54a5273dd92 100644
--- a/usr.bin/ssh/sshd.c
+++ b/usr.bin/ssh/sshd.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.130 2000/10/11 20:27:24 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.131 2000/10/12 09:59:20 markus Exp $");
 
 #include "xmalloc.h"
 #include "rsa.h"
@@ -1135,7 +1135,7 @@ do_ssh1_kex()
 	packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
 
 	/* Declare which ciphers we support. */
-	packet_put_int(cipher_mask1());
+	packet_put_int(cipher_mask_ssh1(0));
 
 	/* Declare supported authentication types. */
 	auth_mask = 0;
@@ -1176,7 +1176,7 @@ do_ssh1_kex()
 	/* Get cipher type and check whether we accept this. */
 	cipher_type = packet_get_char();
 
-	if (!(cipher_mask1() & (1 << cipher_type)))
+	if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
 		packet_disconnect("Warning: client selects unsupported cipher.");
 
 	/* Get check bytes from the packet.  These must match those we