- (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@
diff --git a/packet.c b/packet.c
index 254e452..9887d25 100644
--- a/packet.c
+++ b/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 @@
/* Session key information for Encryption and MAC */
Newkeys *newkeys[MODE_MAX];
-static u_int32_t read_seqnr = 0;
-static u_int32_t send_seqnr = 0;
+static struct packet_state {
+ 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 @@
/* 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 @@
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 @@
return (cipher_get_number(receive_context.cipher));
}
-
-u_int32_t
-packet_get_seqnr(int mode)
+void
+packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
{
- 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)
- read_seqnr = seqnr;
- else if (mode == MODE_OUT)
- send_seqnr = seqnr;
- else
- fatal("packet_set_seqnr: bad mode %d", mode);
+ struct packet_state *state;
+
+ state = (mode == MODE_IN) ? &p_read : &p_send;
+ state->seqnr = seqnr;
+ state->blocks = blocks;
+ state->packets = packets;
}
/* returns 1 if connection is via ipv4 */
@@ -562,6 +582,7 @@
Mac *mac;
Comp *comp;
CipherContext *cc;
+ u_int64_t *max_blocks;
int encrypt;
debug2("set_newkeys: mode %d", mode);
@@ -569,9 +590,13 @@
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 @@
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 @@
/* 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 @@
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 @@
* 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;
- if (++read_seqnr == 0)
+ *seqnr_p = p_read.seqnr;
+ 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 @@
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;
+}