Vendor import of OpenSSH 3.1

1 files changed, 228 insertions, 126 deletions

diff --git a/crypto/openssh/sshconnect.c b/crypto/openssh/sshconnect.c
index 31d0696..afa40be 100644
--- a/crypto/openssh/sshconnect.c
+++ b/crypto/openssh/sshconnect.c
@@ -13,7 +13,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.104 2001/04/12 19:15:25 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.119 2002/01/21 15:13:51 markus Exp $");
 
 #include <openssl/bn.h>
 
@@ -31,6 +31,7 @@ RCSID("$OpenBSD: sshconnect.c,v 1.104 2001/04/12 19:15:25 markus Exp $");
 #include "readconf.h"
 #include "atomicio.h"
 #include "misc.h"
+#include "readpass.h"
 
 char *client_version_string = NULL;
 char *server_version_string = NULL;
@@ -38,13 +39,31 @@ char *server_version_string = NULL;
 extern Options options;
 extern char *__progname;
 
-/* AF_UNSPEC or AF_INET or AF_INET6 */
-extern int IPv4or6;
+static const char *
+sockaddr_ntop(struct sockaddr *sa)
+{
+	void *addr;
+	static char addrbuf[INET6_ADDRSTRLEN];
+
+	switch (sa->sa_family) {
+	case AF_INET:
+		addr = &((struct sockaddr_in *)sa)->sin_addr;
+		break;
+	case AF_INET6:
+		addr = &((struct sockaddr_in6 *)sa)->sin6_addr;
+		break;
+	default:
+		/* This case should be protected against elsewhere */
+		abort();	/* XXX abort is bad -- do something else */
+	}
+	inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf));
+	return addrbuf;
+}
 
 /*
  * Connect to the given ssh server using a proxy command.
  */
-int
+static int
 ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
 		  const char *proxy_command)
 {
@@ -87,7 +106,7 @@ ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
 	/* Create pipes for communicating with the proxy. */
 	if (pipe(pin) < 0 || pipe(pout) < 0)
 		fatal("Could not create pipes to communicate with the proxy: %.100s",
-		      strerror(errno));
+		    strerror(errno));
 
 	debug("Executing proxy command: %.500s", command_string);
 
@@ -138,16 +157,18 @@ ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
 	/* Set the connection file descriptors. */
 	packet_set_connection(pout[0], pin[1]);
 
-	return 1;
+	/* Indicate OK return */
+	return 0;
 }
 
 /*
  * Creates a (possibly privileged) socket for use as the ssh connection.
  */
-int
+static int
 ssh_create_socket(struct passwd *pw, int privileged, int family)
 {
-	int sock;
+	int sock, gaierr;
+	struct addrinfo hints, *res;
 
 	/*
 	 * If we are running as root and want to connect to a privileged
@@ -160,17 +181,40 @@ ssh_create_socket(struct passwd *pw, int privileged, int family)
 			error("rresvport: af=%d %.100s", family, strerror(errno));
 		else
 			debug("Allocated local port %d.", p);
-	} else {
-		/*
-		 * Just create an ordinary socket on arbitrary port.  We use
-		 * the user's uid to create the socket.
-		 */
-		temporarily_use_uid(pw);
-		sock = socket(family, SOCK_STREAM, 0);
-		if (sock < 0)
-			error("socket: %.100s", strerror(errno));
-		restore_uid();
+		return sock;
 	}
+	/*
+	 * Just create an ordinary socket on arbitrary port.  We use
+	 * the user's uid to create the socket.
+	 */
+	temporarily_use_uid(pw);
+	sock = socket(family, SOCK_STREAM, 0);
+	if (sock < 0)
+		error("socket: %.100s", strerror(errno));
+	restore_uid();
+
+	/* Bind the socket to an alternative local IP address */
+	if (options.bind_address == NULL)
+		return sock;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = family;
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_flags = AI_PASSIVE;
+	gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
+	if (gaierr) {
+		error("getaddrinfo: %s: %s", options.bind_address,
+		    gai_strerror(gaierr));
+		close(sock);
+		return -1;
+	}
+	if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
+		error("bind: %s: %s", options.bind_address, strerror(errno));
+		close(sock);
+		freeaddrinfo(res);
+		return -1;
+	}
+	freeaddrinfo(res);
 	return sock;
 }
 
@@ -184,12 +228,17 @@ ssh_create_socket(struct passwd *pw, int privileged, int family)
  * second).  If proxy_command is non-NULL, it specifies the command (with %h
  * and %p substituted for host and port, respectively) to use to contact
  * the daemon.
+ * Return values:
+ *    0 for OK
+ *    ECONNREFUSED if we got a "Connection Refused" by the peer on any address
+ *    ECONNABORTED if we failed without a "Connection refused"
+ * Suitable error messages for the connection failure will already have been
+ * printed.
  */
 int
 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
-	    u_short port, int connection_attempts,
-	    int anonymous, struct passwd *pw,
-	    const char *proxy_command)
+    u_short port, int family, int connection_attempts,
+    int anonymous, struct passwd *pw, const char *proxy_command)
 {
 	int gaierr;
 	int on = 1;
@@ -198,9 +247,15 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	struct addrinfo hints, *ai, *aitop;
 	struct linger linger;
 	struct servent *sp;
+	/*
+	 * Did we get only other errors than "Connection refused" (which
+	 * should block fallback to rsh and similar), or did we get at least
+	 * one "Connection refused"?
+	 */
+	int full_failure = 1;
 
 	debug("ssh_connect: getuid %u geteuid %u anon %d",
-	      (u_int) getuid(), (u_int) geteuid(), anonymous);
+	    (u_int) getuid(), (u_int) geteuid(), anonymous);
 
 	/* Get default port if port has not been set. */
 	if (port == 0) {
@@ -217,7 +272,7 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	/* No proxy command. */
 
 	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = IPv4or6;
+	hints.ai_family = family;
 	hints.ai_socktype = SOCK_STREAM;
 	snprintf(strport, sizeof strport, "%d", port);
 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
@@ -228,8 +283,8 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	 * Try to connect several times.  On some machines, the first time
 	 * will sometimes fail.  In general socket code appears to behave
 	 * quite magically on many machines.
-	 */
-	for (attempt = 0; attempt < connection_attempts; attempt++) {
+		 */
+	for (attempt = 0; ;) {
 		if (attempt > 0)
 			debug("Trying again...");
 
@@ -252,6 +307,7 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 			    !anonymous && geteuid() == 0,
 			    ai->ai_family);
 			if (sock < 0)
+				/* Any error is already output */
 				continue;
 
 			/* Connect to the host.  We use the user's uid in the
@@ -265,7 +321,11 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 				restore_uid();
 				break;
 			} else {
-				debug("connect: %.100s", strerror(errno));
+				if (errno == ECONNREFUSED)
+					full_failure = 0;
+				log("ssh: connect to address %s port %s: %s",
+				    sockaddr_ntop(ai->ai_addr), strport,
+				    strerror(errno));
 				restore_uid();
 				/*
 				 * Close the failed socket; there appear to
@@ -273,13 +333,15 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 				 * which connect() has already returned an
 				 * error.
 				 */
-				shutdown(sock, SHUT_RDWR);
 				close(sock);
 			}
 		}
 		if (ai)
 			break;	/* Successful connection. */
 
+		attempt++;
+		if (attempt >= connection_attempts)
+			break;
 		/* Sleep a moment before retrying. */
 		sleep(1);
 	}
@@ -288,7 +350,7 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 
 	/* Return failure if we didn't get a successful connection. */
 	if (attempt >= connection_attempts)
-		return 0;
+		return full_failure ? ECONNABORTED : ECONNREFUSED;
 
 	debug("Connection established.");
 
@@ -310,14 +372,14 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	/* Set the connection. */
 	packet_set_connection(sock, sock);
 
-	return 1;
+	return 0;
 }
 
 /*
  * Waits for the server identification string, and sends our own
  * identification string.
  */
-void
+static void
 ssh_exchange_identification(void)
 {
 	char buf[256], remote_version[256];	/* must be same size! */
@@ -359,12 +421,12 @@ ssh_exchange_identification(void)
 	    &remote_major, &remote_minor, remote_version) != 3)
 		fatal("Bad remote protocol version identification: '%.100s'", buf);
 	debug("Remote protocol version %d.%d, remote software version %.100s",
-	      remote_major, remote_minor, remote_version);
+	    remote_major, remote_minor, remote_version);
 
 	compat_datafellows(remote_version);
 	mismatch = 0;
 
-	switch(remote_major) {
+	switch (remote_major) {
 	case 1:
 		if (remote_minor == 99 &&
 		    (options.protocol & SSH_PROTO_2) &&
@@ -402,8 +464,6 @@ ssh_exchange_identification(void)
 		fatal("Protocol major versions differ: %d vs. %d",
 		    (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
 		    remote_major);
-	if (compat20)
-		packet_set_ssh2_format();
 	/* Send our own protocol version identification. */
 	snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
 	    compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
@@ -418,61 +478,38 @@ ssh_exchange_identification(void)
 }
 
 /* defaults to 'no' */
-int
-read_yes_or_no(const char *prompt, int defval)
+static int
+confirm(const char *prompt)
 {
-	char buf[1024];
-	FILE *f;
-	int retval = -1;
+	const char *msg, *again = "Please type 'yes' or 'no': ";
+	char *p;
+	int ret = -1;
 
 	if (options.batch_mode)
 		return 0;
-
-	if (isatty(STDIN_FILENO))
-		f = stdin;
-	else
-		f = fopen(_PATH_TTY, "rw");
-
-	if (f == NULL)
-		return 0;
-
-	fflush(stdout);
-
-	while (1) {
-		fprintf(stderr, "%s", prompt);
-		if (fgets(buf, sizeof(buf), f) == NULL) {
-			/* Print a newline (the prompt probably didn\'t have one). */
-			fprintf(stderr, "\n");
-			strlcpy(buf, "no", sizeof buf);
-		}
-		/* Remove newline from response. */
-		if (strchr(buf, '\n'))
-			*strchr(buf, '\n') = 0;
-
-		if (buf[0] == 0)
-			retval = defval;
-		if (strcmp(buf, "yes") == 0)
-			retval = 1;
-		else if (strcmp(buf, "no") == 0)
-			retval = 0;
-		else
-			fprintf(stderr, "Please type 'yes' or 'no'.\n");
-
-		if (retval != -1) {
-			if (f != stdin)
-				fclose(f);
-			return retval;
-		}
+	for (msg = prompt;;msg = again) {
+		p = read_passphrase(msg, RP_ECHO);
+		if (p == NULL ||
+		    (p[0] == '\0') || (p[0] == '\n') ||
+		    strncasecmp(p, "no", 2) == 0)
+			ret = 0;
+		if (strncasecmp(p, "yes", 3) == 0)
+			ret = 1;
+		if (p)
+			xfree(p);
+		if (ret != -1)
+			return ret;
 	}
 }
 
 /*
- * check whether the supplied host key is valid, return only if ok.
+ * check whether the supplied host key is valid, return -1 if the key
+ * is not valid. the user_hostfile will not be updated if 'readonly' is true.
  */
 
-void
+static int
 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
-	const char *user_hostfile, const char *system_hostfile)
+    int readonly, const char *user_hostfile, const char *system_hostfile)
 {
 	Key *file_key;
 	char *type = key_type(host_key);
@@ -482,7 +519,8 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 	HostStatus ip_status;
 	int local = 0, host_ip_differ = 0;
 	char ntop[NI_MAXHOST];
-	int host_line, ip_line;
+	char msg[1024];
+	int len, host_line, ip_line;
 	const char *host_file = NULL, *ip_file = NULL;
 
 	/*
@@ -496,19 +534,22 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 	/**  hostaddr == 0! */
 	switch (hostaddr->sa_family) {
 	case AF_INET:
-		local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+		local = (ntohl(((struct sockaddr_in *)hostaddr)->
+		   sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
 		break;
 	case AF_INET6:
-		local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
+		local = IN6_IS_ADDR_LOOPBACK(
+		    &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
 		break;
 	default:
 		local = 0;
 		break;
 	}
-	if (local && options.host_key_alias == NULL) {
+	if (options.no_host_authentication_for_localhost == 1 && local &&
+	    options.host_key_alias == NULL) {
 		debug("Forcing accepting of host key for "
 		    "loopback/localhost.");
-		return;
+		return 0;
 	}
 
 	/*
@@ -552,10 +593,12 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 	 * hosts or in the systemwide list.
 	 */
 	host_file = user_hostfile;
-	host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line);
+	host_status = check_host_in_hostfile(host_file, host, host_key,
+	    file_key, &host_line);
 	if (host_status == HOST_NEW) {
 		host_file = system_hostfile;
-		host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line);
+		host_status = check_host_in_hostfile(host_file, host, host_key,
+		    file_key, &host_line);
 	}
 	/*
 	 * Also perform check for the ip address, skip the check if we are
@@ -565,10 +608,12 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		Key *ip_key = key_new(host_key->type);
 
 		ip_file = user_hostfile;
-		ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line);
+		ip_status = check_host_in_hostfile(ip_file, ip, host_key,
+		    ip_key, &ip_line);
 		if (ip_status == HOST_NEW) {
 			ip_file = system_hostfile;
-			ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line);
+			ip_status = check_host_in_hostfile(ip_file, ip,
+			    host_key, ip_key, &ip_line);
 		}
 		if (host_status == HOST_CHANGED &&
 		    (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
@@ -587,32 +632,46 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		    host, type);
 		debug("Found key in %s:%d", host_file, host_line);
 		if (options.check_host_ip && ip_status == HOST_NEW) {
-			if (!add_host_to_hostfile(user_hostfile, ip, host_key))
-				log("Failed to add the %s host key for IP address '%.128s' to the list of known hosts (%.30s).",
-				    type, ip, user_hostfile);
-			else
-				log("Warning: Permanently added the %s host key for IP address '%.128s' to the list of known hosts.",
+			if (readonly)
+				log("%s host key for IP address "
+				    "'%.128s' not in list of known hosts.",
 				    type, ip);
+			else if (!add_host_to_hostfile(user_hostfile, ip,
+			    host_key))
+				log("Failed to add the %s host key for IP "
+				    "address '%.128s' to the list of known "
+				    "hosts (%.30s).", type, ip, user_hostfile);
+			else
+				log("Warning: Permanently added the %s host "
+				    "key for IP address '%.128s' to the list "
+				    "of known hosts.", type, ip);
 		}
 		break;
 	case HOST_NEW:
+		if (readonly)
+			goto fail;
 		/* The host is new. */
 		if (options.strict_host_key_checking == 1) {
-			/* User has requested strict host key checking.  We will not add the host key
-			   automatically.  The only alternative left is to abort. */
-			fatal("No %s host key is known for %.200s and you have requested strict checking.", type, host);
+			/*
+			 * User has requested strict host key checking.  We
+			 * will not add the host key automatically.  The only
+			 * alternative left is to abort.
+			 */
+			error("No %s host key is known for %.200s and you "
+			    "have requested strict checking.", type, host);
+			goto fail;
 		} else if (options.strict_host_key_checking == 2) {
 			/* The default */
-			char prompt[1024];
 			fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
-			snprintf(prompt, sizeof(prompt),
-			    "The authenticity of host '%.200s (%s)' can't be established.\n"
+			snprintf(msg, sizeof(msg),
+			    "The authenticity of host '%.200s (%s)' can't be "
+			    "established.\n"
 			    "%s key fingerprint is %s.\n"
-			    "Are you sure you want to continue connecting (yes/no)? ",
-			    host, ip, type, fp);
+			    "Are you sure you want to continue connecting "
+			    "(yes/no)? ", host, ip, type, fp);
 			xfree(fp);
-			if (!read_yes_or_no(prompt, -1))
-				fatal("Aborted by user!");
+			if (!confirm(msg))
+				goto fail;
 		}
 		if (options.check_host_ip && ip_status == HOST_NEW) {
 			snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
@@ -620,13 +679,16 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		} else
 			hostp = host;
 
-		/* If not in strict mode, add the key automatically to the local known_hosts file. */
+		/*
+		 * If not in strict mode, add the key automatically to the
+		 * local known_hosts file.
+		 */
 		if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
-			log("Failed to add the host to the list of known hosts (%.500s).",
-			    user_hostfile);
+			log("Failed to add the host to the list of known "
+			    "hosts (%.500s).", user_hostfile);
 		else
-			log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.",
-			    hostp, type);
+			log("Warning: Permanently added '%.200s' (%s) to the "
+			    "list of known hosts.", hostp, type);
 		break;
 	case HOST_CHANGED:
 		if (options.check_host_ip && host_ip_differ) {
@@ -668,8 +730,11 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		 * If strict host key checking is in use, the user will have
 		 * to edit the key manually and we can only abort.
 		 */
-		if (options.strict_host_key_checking)
-			fatal("%s host key for %.200s has changed and you have requested strict checking.", type, host);
+		if (options.strict_host_key_checking) {
+			error("%s host key for %.200s has changed and you have "
+			    "requested strict checking.", type, host);
+			goto fail;
+		}
 
 		/*
 		 * If strict host key checking has not been requested, allow
@@ -677,20 +742,26 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		 * agent forwarding.
 		 */
 		if (options.password_authentication) {
-			error("Password authentication is disabled to avoid trojan horses.");
+			error("Password authentication is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.password_authentication = 0;
 		}
 		if (options.forward_agent) {
-			error("Agent forwarding is disabled to avoid trojan horses.");
+			error("Agent forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.forward_agent = 0;
 		}
 		if (options.forward_x11) {
-			error("X11 forwarding is disabled to avoid trojan horses.");
+			error("X11 forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.forward_x11 = 0;
 		}
-		if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) {
-			error("Port forwarding is disabled to avoid trojan horses.");
-			options.num_local_forwards = options.num_remote_forwards = 0;
+		if (options.num_local_forwards > 0 ||
+		    options.num_remote_forwards > 0) {
+			error("Port forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
+			options.num_local_forwards =
+			    options.num_remote_forwards = 0;
 		}
 		/*
 		 * XXX Should permit the user to change to use the new id.
@@ -704,22 +775,53 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 
 	if (options.check_host_ip && host_status != HOST_CHANGED &&
 	    ip_status == HOST_CHANGED) {
-		log("Warning: the %s host key for '%.200s' "
-		    "differs from the key for the IP address '%.128s'",
-		    type, host, ip);
-		if (host_status == HOST_OK)
-			log("Matching host key in %s:%d", host_file, host_line);
-		log("Offending key for IP in %s:%d", ip_file, ip_line);
+		snprintf(msg, sizeof(msg),
+		    "Warning: the %s host key for '%.200s' "
+		    "differs from the key for the IP address '%.128s'"
+		    "\nOffending key for IP in %s:%d",
+		    type, host, ip, ip_file, ip_line);
+		if (host_status == HOST_OK) {
+			len = strlen(msg);
+			snprintf(msg + len, sizeof(msg) - len,
+			    "\nMatching host key in %s:%d",
+			     host_file, host_line);
+		}
 		if (options.strict_host_key_checking == 1) {
-			fatal("Exiting, you have requested strict checking.");
+			log(msg);
+			error("Exiting, you have requested strict checking.");
+			goto fail;
 		} else if (options.strict_host_key_checking == 2) {
-			if (!read_yes_or_no("Are you sure you want " \
-			    "to continue connecting (yes/no)? ", -1))
-				fatal("Aborted by user!");
+			strlcat(msg, "\nAre you sure you want "
+			    "to continue connecting (yes/no)? ", sizeof(msg));
+			if (!confirm(msg))
+				goto fail;
+		} else {
+			log(msg);
 		}
 	}
 
 	xfree(ip);
+	return 0;
+
+fail:
+	xfree(ip);
+	return -1;
+}
+
+int
+verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
+{
+	struct stat st;
+
+	/* return ok if the key can be found in an old keyfile */
+	if (stat(options.system_hostfile2, &st) == 0 ||
+	    stat(options.user_hostfile2, &st) == 0) {
+		if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
+		    options.user_hostfile2, options.system_hostfile2) == 0)
+			return 0;
+	}
+	return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
+	    options.user_hostfile, options.system_hostfile);
 }
 
 /*
@@ -769,7 +871,7 @@ ssh_put_password(char *password)
 	char *padded;
 
 	if (datafellows & SSH_BUG_PASSWORDPAD) {
-		packet_put_string(password, strlen(password));
+		packet_put_cstring(password);
 		return;
 	}
 	size = roundup(strlen(password) + 1, 32);