- (djm) OpenBSD CVS Sync

- markus@cvs.openbsd.org 2003/04/02 09:48:07
     [clientloop.c monitor.c monitor_wrap.c packet.c packet.h readconf.c]
     [readconf.h serverloop.c sshconnect2.c]
     reapply rekeying chage, tested by henning@, ok djm@

ChangeLog

@@ -2,6 +2,11 @@
  - (djm) Bug #539: Specify creation mode with O_CREAT for lastlog. Report 
    from matth@eecs.berkeley.edu
  - (djm) Make the spec work with Redhat 9.0 (which renames sharutils)
+ - (djm) OpenBSD CVS Sync
+   - markus@cvs.openbsd.org 2003/04/02 09:48:07
+     [clientloop.c monitor.c monitor_wrap.c packet.c packet.h readconf.c]
+     [readconf.h serverloop.c sshconnect2.c]
+     reapply rekeying chage, tested by henning@, ok djm@
 
 20030402
  - (bal) if IP_TOS is not found or broken don't try to compile in
@@ -1304,4 +1309,4 @@
      save auth method before monitor_reset_key_state(); bugzilla bug #284;
      ok provos@
 
-$Id: ChangeLog,v 1.2651 2003/04/09 09:41:25 djm Exp $
+$Id: ChangeLog,v 1.2652 2003/04/09 10:50:06 djm Exp $

clientloop.c

@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.107 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.108 2003/04/02 09:48:07 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -968,9 +968,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
 		/* Do channel operations unless rekeying in progress. */
 		if (!rekeying) {
 			channel_after_select(readset, writeset);
-
+			if (need_rekeying || packet_need_rekeying()) {
-			if (need_rekeying) {
+				debug("need rekeying");
-				debug("user requests rekeying");
 				xxx_kex->done = 0;
 				kex_send_kexinit(xxx_kex);
 				need_rekeying = 0;

monitor.c

@@ -25,7 +25,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: monitor.c,v 1.36 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: monitor.c,v 1.37 2003/04/02 09:48:07 markus Exp $");
 
 #include <openssl/dh.h>
 
@@ -1497,6 +1497,8 @@ mm_get_keystate(struct monitor *pmonitor)
 	Buffer m;
 	u_char *blob, *p;
 	u_int bloblen, plen;
+	u_int32_t seqnr, packets;
+	u_int64_t blocks;
 
 	debug3("%s: Waiting for new keys", __func__);
 
@@ -1526,8 +1528,14 @@ mm_get_keystate(struct monitor *pmonitor)
 	xfree(blob);
 
 	/* Now get sequence numbers for the packets */
-	packet_set_seqnr(MODE_OUT, buffer_get_int(&m));
+	seqnr = buffer_get_int(&m);
-	packet_set_seqnr(MODE_IN, buffer_get_int(&m));
+	blocks = buffer_get_int64(&m);
+	packets = buffer_get_int(&m);
+	packet_set_state(MODE_OUT, seqnr, blocks, packets);
+	seqnr = buffer_get_int(&m);
+	blocks = buffer_get_int64(&m);
+	packets = buffer_get_int(&m);
+	packet_set_state(MODE_IN, seqnr, blocks, packets);
 
  skip:
 	/* Get the key context */

monitor_wrap.c

@@ -25,7 +25,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: monitor_wrap.c,v 1.24 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: monitor_wrap.c,v 1.25 2003/04/02 09:48:07 markus Exp $");
 
 #include <openssl/bn.h>
 #include <openssl/dh.h>
@@ -520,6 +520,8 @@ mm_send_keystate(struct monitor *pmonitor)
 	Buffer m;
 	u_char *blob, *p;
 	u_int bloblen, plen;
+	u_int32_t seqnr, packets;
+	u_int64_t blocks;
 
 	buffer_init(&m);
 
@@ -568,8 +570,14 @@ mm_send_keystate(struct monitor *pmonitor)
 	buffer_put_string(&m, blob, bloblen);
 	xfree(blob);
 
-	buffer_put_int(&m, packet_get_seqnr(MODE_OUT));
+	packet_get_state(MODE_OUT, &seqnr, &blocks, &packets);
-	buffer_put_int(&m, packet_get_seqnr(MODE_IN));
+	buffer_put_int(&m, seqnr);
+	buffer_put_int64(&m, blocks);
+	buffer_put_int(&m, packets);
+	packet_get_state(MODE_OUT, &seqnr, &blocks, &packets);
+	buffer_put_int(&m, seqnr);
+	buffer_put_int64(&m, blocks);
+	buffer_put_int(&m, packets);
 
 	debug3("%s: New keys have been sent", __func__);
  skip:

packet.c

@@ -37,7 +37,9 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: packet.c,v 1.104 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: packet.c,v 1.105 2003/04/02 09:48:07 markus Exp $");
+
+#include <sys/queue.h>
 
 #include "xmalloc.h"
 #include "buffer.h"
@@ -116,8 +118,14 @@ static int interactive_mode = 0;
 
 /* Session key information for Encryption and MAC */
 Newkeys *newkeys[MODE_MAX];
-static u_int32_t read_seqnr = 0;
+static struct packet_state {
-static u_int32_t send_seqnr = 0;
+	u_int32_t seqnr;
+	u_int32_t packets;
+	u_int64_t blocks;
+} p_read, p_send;
+
+static u_int64_t max_blocks_in, max_blocks_out;
+static u_int32_t rekey_limit;
 
 /* Session key for protocol v1 */
 static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
@@ -126,6 +134,13 @@ static u_int ssh1_keylen;
 /* roundup current message to extra_pad bytes */
 static u_char extra_pad = 0;
 
+struct packet {
+	TAILQ_ENTRY(packet) next;
+	u_char type;
+	Buffer payload;
+};
+TAILQ_HEAD(, packet) outgoing;
+
 /*
  * Sets the descriptors used for communication.  Disables encryption until
  * packet_set_encryption_key is called.
@@ -148,6 +163,7 @@ packet_set_connection(int fd_in, int fd_out)
 		buffer_init(&output);
 		buffer_init(&outgoing_packet);
 		buffer_init(&incoming_packet);
+		TAILQ_INIT(&outgoing);
 	}
 	/* Kludge: arrange the close function to be called from fatal(). */
 	fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
@@ -254,22 +270,26 @@ packet_get_ssh1_cipher()
 	return (cipher_get_number(receive_context.cipher));
 }
 
-
+void
-u_int32_t
+packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
-packet_get_seqnr(int mode)
 {
-	return (mode == MODE_IN ? read_seqnr : send_seqnr);
+	struct packet_state *state;
+
+	state = (mode == MODE_IN) ? &p_read : &p_send;
+	*seqnr = state->seqnr;
+	*blocks = state->blocks;
+	*packets = state->packets;
 }
 
 void
-packet_set_seqnr(int mode, u_int32_t seqnr)
+packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
 {
-	if (mode == MODE_IN)
+	struct packet_state *state;
-		read_seqnr = seqnr;
+
-	else if (mode == MODE_OUT)
+	state = (mode == MODE_IN) ? &p_read : &p_send;
-		send_seqnr = seqnr;
+	state->seqnr = seqnr;
-	else
+	state->blocks = blocks;
-		fatal("packet_set_seqnr: bad mode %d", mode);
+	state->packets = packets;
 }
 
 /* returns 1 if connection is via ipv4 */
@@ -562,6 +582,7 @@ set_newkeys(int mode)
 	Mac *mac;
 	Comp *comp;
 	CipherContext *cc;
+	u_int64_t *max_blocks;
 	int encrypt;
 
 	debug2("set_newkeys: mode %d", mode);
@@ -569,9 +590,13 @@ set_newkeys(int mode)
 	if (mode == MODE_OUT) {
 		cc = &send_context;
 		encrypt = CIPHER_ENCRYPT;
+		p_send.packets = p_send.blocks = 0;
+		max_blocks = &max_blocks_out;
 	} else {
 		cc = &receive_context;
 		encrypt = CIPHER_DECRYPT;
+		p_read.packets = p_read.blocks = 0;
+		max_blocks = &max_blocks_in;
 	}
 	if (newkeys[mode] != NULL) {
 		debug("set_newkeys: rekeying");
@@ -610,13 +635,16 @@ set_newkeys(int mode)
 			buffer_compress_init_recv();
 		comp->enabled = 1;
 	}
+	*max_blocks = ((u_int64_t)1 << (enc->block_size*2));
+	if (rekey_limit)
+		*max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
 }
 
 /*
  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
  */
 static void
-packet_send2(void)
+packet_send2_wrapped(void)
 {
 	u_char type, *cp, *macbuf = NULL;
 	u_char padlen, pad;
@@ -698,10 +726,10 @@ packet_send2(void)
 
 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
 	if (mac && mac->enabled) {
-		macbuf = mac_compute(mac, send_seqnr,
+		macbuf = mac_compute(mac, p_send.seqnr,
 		    buffer_ptr(&outgoing_packet),
 		    buffer_len(&outgoing_packet));
-		DBG(debug("done calc MAC out #%d", send_seqnr));
+		DBG(debug("done calc MAC out #%d", p_send.seqnr));
 	}
 	/* encrypt packet and append to output buffer. */
 	cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
@@ -715,14 +743,64 @@ packet_send2(void)
 	buffer_dump(&output);
 #endif
 	/* increment sequence number for outgoing packets */
-	if (++send_seqnr == 0)
+	if (++p_send.seqnr == 0)
 		log("outgoing seqnr wraps around");
+	if (++p_send.packets == 0)
+		if (!(datafellows & SSH_BUG_NOREKEY))
+			fatal("XXX too many packets with same key");
+	p_send.blocks += (packet_length + 4) / block_size;
 	buffer_clear(&outgoing_packet);
 
 	if (type == SSH2_MSG_NEWKEYS)
 		set_newkeys(MODE_OUT);
 }
 
+static void
+packet_send2(void)
+{
+	static int rekeying = 0;
+	struct packet *p;
+	u_char type, *cp;
+
+	cp = buffer_ptr(&outgoing_packet);
+	type = cp[5];
+
+	/* during rekeying we can only send key exchange messages */
+	if (rekeying) {
+		if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
+		    (type <= SSH2_MSG_TRANSPORT_MAX))) {
+			debug("enqueue packet: %u", type);
+			p = xmalloc(sizeof(*p));
+			p->type = type;
+			memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
+			buffer_init(&outgoing_packet);
+			TAILQ_INSERT_TAIL(&outgoing, p, next);
+			return;
+		}
+	}
+
+	/* rekeying starts with sending KEXINIT */
+	if (type == SSH2_MSG_KEXINIT)
+		rekeying = 1;
+
+	packet_send2_wrapped();
+
+	/* after a NEWKEYS message we can send the complete queue */
+	if (type == SSH2_MSG_NEWKEYS) {
+		rekeying = 0;
+		while ((p = TAILQ_FIRST(&outgoing))) {
+			type = p->type;
+			debug("dequeue packet: %u", type);
+			buffer_free(&outgoing_packet);
+			memcpy(&outgoing_packet, &p->payload,
+			    sizeof(Buffer));
+			TAILQ_REMOVE(&outgoing, p, next);
+			xfree(p);
+			packet_send2_wrapped();
+		}
+	}
+}
+
 void
 packet_send(void)
 {
@@ -966,18 +1044,22 @@ packet_read_poll2(u_int32_t *seqnr_p)
 	 * increment sequence number for incoming packet
 	 */
 	if (mac && mac->enabled) {
-		macbuf = mac_compute(mac, read_seqnr,
+		macbuf = mac_compute(mac, p_read.seqnr,
 		    buffer_ptr(&incoming_packet),
 		    buffer_len(&incoming_packet));
 		if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
 			packet_disconnect("Corrupted MAC on input.");
-		DBG(debug("MAC #%d ok", read_seqnr));
+		DBG(debug("MAC #%d ok", p_read.seqnr));
 		buffer_consume(&input, mac->mac_len);
 	}
 	if (seqnr_p != NULL)
-		*seqnr_p = read_seqnr;
+		*seqnr_p = p_read.seqnr;
-	if (++read_seqnr == 0)
+	if (++p_read.seqnr == 0)
 		log("incoming seqnr wraps around");
+	if (++p_read.packets == 0)
+		if (!(datafellows & SSH_BUG_NOREKEY))
+			fatal("XXX too many packets with same key");
+	p_read.blocks += (packet_length + 4) / block_size;
 
 	/* get padlen */
 	cp = buffer_ptr(&incoming_packet);
@@ -1416,3 +1498,22 @@ packet_send_ignore(int nbytes)
 		rand >>= 8;
 	}
 }
+
+#define MAX_PACKETS	(1<<31)
+int
+packet_need_rekeying(void)
+{
+	if (datafellows & SSH_BUG_NOREKEY)
+		return 0;
+	return
+	    (p_send.packets > MAX_PACKETS) ||
+	    (p_read.packets > MAX_PACKETS) ||
+	    (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
+	    (max_blocks_in  && (p_read.blocks > max_blocks_in));
+}
+
+void
+packet_set_rekey_limit(u_int32_t bytes)
+{
+	rekey_limit = bytes;
+}

packet.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: packet.h,v 1.37 2003/04/01 10:22:21 markus Exp $	*/
+/*	$OpenBSD: packet.h,v 1.38 2003/04/02 09:48:07 markus Exp $	*/
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -62,8 +62,8 @@ int	 packet_get_keyiv_len(int);
 void	 packet_get_keyiv(int, u_char *, u_int);
 int	 packet_get_keycontext(int, u_char *);
 void	 packet_set_keycontext(int, u_char *);
-u_int32_t packet_get_seqnr(int);
+void	 packet_get_state(int, u_int32_t *, u_int64_t *, u_int32_t *);
-void	 packet_set_seqnr(int, u_int32_t);
+void	 packet_set_state(int, u_int32_t, u_int64_t, u_int32_t);
 int	 packet_get_ssh1_cipher(void);
 void	 packet_set_iv(int, u_char *);
 
@@ -96,4 +96,7 @@ do { \
 	} \
 } while (0)
 
+int	 packet_need_rekeying(void);
+void	 packet_set_rekey_limit(u_int32_t);
+
 #endif				/* PACKET_H */

readconf.c

@@ -12,7 +12,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: readconf.c,v 1.104 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: readconf.c,v 1.105 2003/04/02 09:48:07 markus Exp $");
 
 #include "ssh.h"
 #include "xmalloc.h"
@@ -114,7 +114,7 @@ typedef enum {
 	oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
 	oHostKeyAlgorithms, oBindAddress, oSmartcardDevice,
 	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
-	oEnableSSHKeysign,
+	oEnableSSHKeysign, oRekeyLimit,
 	oDeprecated
 } OpCodes;
 
@@ -188,6 +188,7 @@ static struct {
 	{ "clearallforwardings", oClearAllForwardings },
 	{ "enablesshkeysign", oEnableSSHKeysign },
 	{ "nohostauthenticationforlocalhost", oNoHostAuthenticationForLocalhost },
+	{ "rekeylimit", oRekeyLimit },
 	{ NULL, oBadOption }
 };
 
@@ -423,6 +424,31 @@ parse_flag:
 		intptr = &options->compression_level;
 		goto parse_int;
 
+	case oRekeyLimit:
+		intptr = &options->rekey_limit;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (arg[0] < '0' || arg[0] > '9')
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+		value = strtol(arg, &endofnumber, 10);
+		if (arg == endofnumber)
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+		switch (toupper(*endofnumber)) {
+		case 'K':
+			value *= 1<<10;
+			break;
+		case 'M':
+			value *= 1<<20;
+			break;
+		case 'G':
+			value *= 1<<30;
+			break;
+		}
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
 	case oIdentityFile:
 		arg = strdelim(&s);
 		if (!arg || *arg == '\0')
@@ -795,6 +821,7 @@ initialize_options(Options * options)
 	options->smartcard_device = NULL;
 	options->enable_ssh_keysign = - 1;
 	options->no_host_authentication_for_localhost = - 1;
+	options->rekey_limit = - 1;
 }
 
 /*
@@ -911,6 +938,8 @@ fill_default_options(Options * options)
 		options->no_host_authentication_for_localhost = 0;
 	if (options->enable_ssh_keysign == -1)
 		options->enable_ssh_keysign = 0;
+	if (options->rekey_limit == -1)
+		options->rekey_limit = 0;
 	/* options->proxy_command should not be set by default */
 	/* options->user will be set in the main program if appropriate */
 	/* options->hostname will be set in the main program if appropriate */

readconf.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: readconf.h,v 1.46 2003/04/01 10:22:21 markus Exp $	*/
+/*	$OpenBSD: readconf.h,v 1.47 2003/04/02 09:48:07 markus Exp $	*/
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -101,6 +101,7 @@ typedef struct {
 	int	clear_forwardings;
 
 	int	enable_ssh_keysign;
+	int	rekey_limit;
 	int	no_host_authentication_for_localhost;
 }       Options;
 

serverloop.c

@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.106 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: serverloop.c,v 1.107 2003/04/02 09:48:07 markus Exp $");
 
 #include "xmalloc.h"
 #include "packet.h"
@@ -771,8 +771,14 @@ server_loop2(Authctxt *authctxt)
 		    &nalloc, 0);
 
 		collect_children();
-		if (!rekeying)
+		if (!rekeying) {
 			channel_after_select(readset, writeset);
+			if (packet_need_rekeying()) {
+				debug("need rekeying");
+				xxx_kex->done = 0;
+				kex_send_kexinit(xxx_kex);
+			}
+		}
 		process_input(readset);
 		if (connection_closed)
 			break;

sshconnect2.c

@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect2.c,v 1.114 2003/04/01 10:22:21 markus Exp $");
+RCSID("$OpenBSD: sshconnect2.c,v 1.115 2003/04/02 09:48:07 markus Exp $");
 
 #include "ssh.h"
 #include "ssh2.h"
@@ -108,6 +108,9 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 		    options.hostkeyalgorithms;
 
+	if (options.rekey_limit)
+		packet_set_rekey_limit(options.rekey_limit);
+
 	/* start key exchange */
 	kex = kex_setup(myproposal);
 	kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;