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Diffstat (limited to 'packet.c')
-rw-r--r--packet.c103
1 files changed, 59 insertions, 44 deletions
diff --git a/packet.c b/packet.c
index 52017defb..beb214f99 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.312 2023/08/28 03:31:16 djm Exp $ */
+/* $OpenBSD: packet.c,v 1.313 2023/12/18 14:45:17 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1207,8 +1207,13 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
sshbuf_dump(state->output, stderr);
#endif
/* increment sequence number for outgoing packets */
- if (++state->p_send.seqnr == 0)
+ if (++state->p_send.seqnr == 0) {
+ if ((ssh->kex->flags & KEX_INITIAL) != 0) {
+ ssh_packet_disconnect(ssh, "outgoing sequence number "
+ "wrapped during initial key exchange");
+ }
logit("outgoing seqnr wraps around");
+ }
if (++state->p_send.packets == 0)
if (!(ssh->compat & SSH_BUG_NOREKEY))
return SSH_ERR_NEED_REKEY;
@@ -1216,6 +1221,11 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
state->p_send.bytes += len;
sshbuf_reset(state->outgoing_packet);
+ if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
+ debug_f("resetting send seqnr %u", state->p_send.seqnr);
+ state->p_send.seqnr = 0;
+ }
+
if (type == SSH2_MSG_NEWKEYS)
r = ssh_set_newkeys(ssh, MODE_OUT);
else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
@@ -1344,8 +1354,7 @@ ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
/* Stay in the loop until we have received a complete packet. */
for (;;) {
/* Try to read a packet from the buffer. */
- r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
- if (r != 0)
+ if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0)
break;
/* If we got a packet, return it. */
if (*typep != SSH_MSG_NONE)
@@ -1416,29 +1425,6 @@ ssh_packet_read(struct ssh *ssh)
return type;
}
-/*
- * Waits until a packet has been received, verifies that its type matches
- * that given, and gives a fatal error and exits if there is a mismatch.
- */
-
-int
-ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
-{
- int r;
- u_char type;
-
- if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
- return r;
- if (type != expected_type) {
- if ((r = sshpkt_disconnect(ssh,
- "Protocol error: expected packet type %d, got %d",
- expected_type, type)) != 0)
- return r;
- return SSH_ERR_PROTOCOL_ERROR;
- }
- return 0;
-}
-
static int
ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
@@ -1629,10 +1615,16 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
goto out;
}
+
if (seqnr_p != NULL)
*seqnr_p = state->p_read.seqnr;
- if (++state->p_read.seqnr == 0)
+ if (++state->p_read.seqnr == 0) {
+ if ((ssh->kex->flags & KEX_INITIAL) != 0) {
+ ssh_packet_disconnect(ssh, "incoming sequence number "
+ "wrapped during initial key exchange");
+ }
logit("incoming seqnr wraps around");
+ }
if (++state->p_read.packets == 0)
if (!(ssh->compat & SSH_BUG_NOREKEY))
return SSH_ERR_NEED_REKEY;
@@ -1698,6 +1690,10 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
#endif
/* reset for next packet */
state->packlen = 0;
+ if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
+ debug_f("resetting read seqnr %u", state->p_read.seqnr);
+ state->p_read.seqnr = 0;
+ }
if ((r = ssh_packet_check_rekey(ssh)) != 0)
return r;
@@ -1720,10 +1716,39 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
if (r != 0)
return r;
- if (*typep) {
- state->keep_alive_timeouts = 0;
- DBG(debug("received packet type %d", *typep));
+ if (*typep == 0) {
+ /* no message ready */
+ return 0;
}
+ state->keep_alive_timeouts = 0;
+ DBG(debug("received packet type %d", *typep));
+
+ /* Always process disconnect messages */
+ if (*typep == SSH2_MSG_DISCONNECT) {
+ if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
+ (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
+ return r;
+ /* Ignore normal client exit notifications */
+ do_log2(ssh->state->server_side &&
+ reason == SSH2_DISCONNECT_BY_APPLICATION ?
+ SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
+ "Received disconnect from %s port %d:"
+ "%u: %.400s", ssh_remote_ipaddr(ssh),
+ ssh_remote_port(ssh), reason, msg);
+ free(msg);
+ return SSH_ERR_DISCONNECTED;
+ }
+
+ /*
+ * Do not implicitly handle any messages here during initial
+ * KEX when in strict mode. They will be need to be allowed
+ * explicitly by the KEX dispatch table or they will generate
+ * protocol errors.
+ */
+ if (ssh->kex != NULL &&
+ (ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict)
+ return 0;
+ /* Implicitly handle transport-level messages */
switch (*typep) {
case SSH2_MSG_IGNORE:
debug3("Received SSH2_MSG_IGNORE");
@@ -1738,19 +1763,6 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
debug("Remote: %.900s", msg);
free(msg);
break;
- case SSH2_MSG_DISCONNECT:
- if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
- (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
- return r;
- /* Ignore normal client exit notifications */
- do_log2(ssh->state->server_side &&
- reason == SSH2_DISCONNECT_BY_APPLICATION ?
- SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
- "Received disconnect from %s port %d:"
- "%u: %.400s", ssh_remote_ipaddr(ssh),
- ssh_remote_port(ssh), reason, msg);
- free(msg);
- return SSH_ERR_DISCONNECTED;
case SSH2_MSG_UNIMPLEMENTED:
if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
return r;
@@ -2242,6 +2254,7 @@ kex_to_blob(struct sshbuf *m, struct kex *kex)
(r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
(r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
(r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
+ (r = sshbuf_put_u32(m, kex->kex_strict)) != 0 ||
(r = sshbuf_put_stringb(m, kex->my)) != 0 ||
(r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
(r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
@@ -2404,6 +2417,7 @@ kex_from_blob(struct sshbuf *m, struct kex **kexp)
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
(r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
+ (r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 ||
(r = sshbuf_get_stringb(m, kex->my)) != 0 ||
(r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
(r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
@@ -2732,6 +2746,7 @@ sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
+ debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf);
if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
(r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
(r = sshpkt_put_cstring(ssh, buf)) != 0 ||
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-28 04:22:14 +0000