upstream commit

avoid fatal() calls in packet code makes ssh-keyscan more
 reliable against server failures ok dtucker@ markus@

opacket.c

@@ -255,8 +255,20 @@ packet_read_seqnr(u_int32_t *seqnr)
 	u_char type;
 	int r;
 
-	if ((r = ssh_packet_read_seqnr(active_state, &type, seqnr)))
+	if ((r = ssh_packet_read_seqnr(active_state, &type, seqnr)) != 0) {
+		switch (r) {
+		case SSH_ERR_CONN_CLOSED:
+			logit("Connection closed by %.200s",
+			    ssh_remote_ipaddr(active_state));
+			cleanup_exit(255);
+		case SSH_ERR_CONN_TIMEOUT:
+			logit("Connection to %.200s timed out while "
+			    "waiting to read", ssh_remote_ipaddr(active_state));
+			cleanup_exit(255);
+		default:
 			fatal("%s: %s", __func__, ssh_err(r));
+		}
+	}
 	return type;
 }
 
@@ -277,3 +289,12 @@ packet_close(void)
 	ssh_packet_close(active_state);
 	active_state = NULL;
 }
+
+void
+packet_process_incoming(const char *buf, u_int len)
+{
+	int r;
+
+	if ((r = ssh_packet_process_incoming(active_state, buf, len)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
+}

opacket.h

@@ -44,6 +44,7 @@ void	 packet_restore_state(void);
 void     packet_set_connection(int, int);
 int	 packet_read_seqnr(u_int32_t *);
 int	 packet_read_poll_seqnr(u_int32_t *);
+void	 packet_process_incoming(const char *buf, u_int len);
 #define packet_set_timeout(timeout, count) \
 	ssh_packet_set_timeout(active_state, (timeout), (count))
 #define packet_connection_is_on_socket() \
@@ -86,8 +87,6 @@ int	 packet_read_poll_seqnr(u_int32_t *);
 	ssh_packet_read(active_state)
 #define packet_read_expect(expected_type) \
 	ssh_packet_read_expect(active_state, (expected_type))
-#define packet_process_incoming(buf, len) \
-	ssh_packet_process_incoming(active_state, (buf), (len))
 #define packet_get_int64() \
 	ssh_packet_get_int64(active_state)
 #define packet_get_bignum(value) \

packet.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.203 2015/01/20 23:14:00 deraadt Exp $ */
+/* $OpenBSD: packet.c,v 1.204 2015/01/28 21:15:47 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1314,26 +1314,22 @@ ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
 				break;
 			}
 		}
-		if (r == 0) {
-			logit("Connection to %.200s timed out while "
-			    "waiting to read", ssh_remote_ipaddr(ssh));
-			cleanup_exit(255);
-		}
+		if (r == 0)
+			return SSH_ERR_CONN_TIMEOUT;
 		/* Read data from the socket. */
 		do {
 			cont = 0;
 			len = roaming_read(state->connection_in, buf,
 			    sizeof(buf), &cont);
 		} while (len == 0 && cont);
-		if (len == 0) {
-			logit("Connection closed by %.200s",
-			    ssh_remote_ipaddr(ssh));
-			cleanup_exit(255);
-		}
+		if (len == 0)
+			return SSH_ERR_CONN_CLOSED;
 		if (len < 0)
-			fatal("Read from socket failed: %.100s", strerror(errno));
+			return SSH_ERR_SYSTEM_ERROR;
+
 		/* Append it to the buffer. */
-		ssh_packet_process_incoming(ssh, buf, len);
+		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
+			return r;
 	}
 	free(setp);
 	return r;
@@ -1787,7 +1783,7 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
  * together with packet_read_poll.
  */
 
-void
+int
 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
 {
 	struct session_state *state = ssh->state;
@@ -1797,14 +1793,15 @@ ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
 		state->keep_alive_timeouts = 0; /* ?? */
 		if (len >= state->packet_discard) {
 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
-				fatal("%s: %s", __func__, ssh_err(r));
-			cleanup_exit(255);
+				return r;
 		}
 		state->packet_discard -= len;
-		return;
+		return 0;
 	}
 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
-		fatal("%s: %s", __func__, ssh_err(r));
+		return r;
+
+	return 0;
 }
 
 int

packet.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.h,v 1.64 2015/01/19 20:30:23 markus Exp $ */
+/* $OpenBSD: packet.h,v 1.65 2015/01/28 21:15:47 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -94,7 +94,7 @@ void     ssh_packet_read_expect(struct ssh *, int type);
 int      ssh_packet_read_poll(struct ssh *);
 int ssh_packet_read_poll1(struct ssh *, u_char *);
 int ssh_packet_read_poll2(struct ssh *, u_char *, u_int32_t *seqnr_p);
-void     ssh_packet_process_incoming(struct ssh *, const char *buf, u_int len);
+int	 ssh_packet_process_incoming(struct ssh *, const char *buf, u_int len);
 int      ssh_packet_read_seqnr(struct ssh *, u_char *, u_int32_t *seqnr_p);
 int      ssh_packet_read_poll_seqnr(struct ssh *, u_char *, u_int32_t *seqnr_p);
 

ssh-keyscan.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keyscan.c,v 1.96 2015/01/20 23:14:00 deraadt Exp $ */
+/* $OpenBSD: ssh-keyscan.c,v 1.97 2015/01/28 21:15:47 djm Exp $ */
 /*
  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
  *
@@ -319,8 +319,10 @@ tcpconnect(char *host)
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = IPv4or6;
 	hints.ai_socktype = SOCK_STREAM;
-	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
-		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
+	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
+		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
+		return -1;
+	}
 	for (ai = aitop; ai; ai = ai->ai_next) {
 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 		if (s < 0) {

ssherr.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ssherr.c,v 1.1 2014/04/30 05:29:56 djm Exp $	*/
+/*	$OpenBSD: ssherr.c,v 1.2 2015/01/28 21:15:47 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -125,6 +125,10 @@ ssh_err(int n)
 		return "KRL file has invalid magic number";
 	case SSH_ERR_KEY_REVOKED:
 		return "Key is revoked";
+	case SSH_ERR_CONN_CLOSED:
+		return "Connection closed";
+	case SSH_ERR_CONN_TIMEOUT:
+		return "Connection timed out";
 	default:
 		return "unknown error";
 	}

ssherr.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ssherr.h,v 1.1 2014/04/30 05:29:56 djm Exp $	*/
+/*	$OpenBSD: ssherr.h,v 1.2 2015/01/28 21:15:47 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -73,6 +73,8 @@
 #define SSH_ERR_BUFFER_READ_ONLY		-49
 #define SSH_ERR_KRL_BAD_MAGIC			-50
 #define SSH_ERR_KEY_REVOKED			-51
+#define SSH_ERR_CONN_CLOSED			-52
+#define SSH_ERR_CONN_TIMEOUT			-53
 
 /* Translate a numeric error code to a human-readable error string */
 const char *ssh_err(int n);