New upstream release (7.3p1).

1 files changed, 33 insertions, 182 deletions

diff --git a/canohost.c b/canohost.c
index 223964ea3..404731d24 100644
--- a/canohost.c
+++ b/canohost.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: canohost.c,v 1.72 2015/03/01 15:44:40 millert Exp $ */
+/* $OpenBSD: canohost.c,v 1.73 2016/03/07 19:02:43 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -35,52 +35,44 @@
 #include "canohost.h"
 #include "misc.h"
 
-static void check_ip_options(int, char *);
-static char *canonical_host_ip = NULL;
-static int cached_port = -1;
-
 /*
- * Return the canonical name of the host at the other end of the socket. The
- * caller should free the returned string.
+ * Returns the remote DNS hostname as a string. The returned string must not
+ * be freed. NB. this will usually trigger a DNS query the first time it is
+ * called.
+ * This function does additional checks on the hostname to mitigate some
+ * attacks on legacy rhosts-style authentication.
+ * XXX is RhostsRSAAuthentication vulnerable to these?
+ * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
  */
 
-static char *
-get_remote_hostname(int sock, int use_dns)
+char *
+remote_hostname(struct ssh *ssh)
 {
         struct sockaddr_storage from;
         socklen_t fromlen;
         struct addrinfo hints, *ai, *aitop;
-        char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST];
+        char name[NI_MAXHOST], ntop2[NI_MAXHOST];
+        const char *ntop = ssh_remote_ipaddr(ssh);
 
         /* Get IP address of client. */
         fromlen = sizeof(from);
         memset(&from, 0, sizeof(from));
-        if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
+        if (getpeername(ssh_packet_get_connection_in(ssh),
+            (struct sockaddr *)&from, &fromlen) < 0) {
                 debug("getpeername failed: %.100s", strerror(errno));
-                cleanup_exit(255);
+                return strdup(ntop);
         }
 
-        if (from.ss_family == AF_INET)
-                check_ip_options(sock, ntop);
-
         ipv64_normalise_mapped(&from, &fromlen);
-
         if (from.ss_family == AF_INET6)
                 fromlen = sizeof(struct sockaddr_in6);
 
-        if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
-            NULL, 0, NI_NUMERICHOST) != 0)
-                fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed");
-
-        if (!use_dns)
-                return xstrdup(ntop);
-
         debug3("Trying to reverse map address %.100s.", ntop);
         /* Map the IP address to a host name. */
         if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
             NULL, 0, NI_NAMEREQD) != 0) {
                 /* Host name not found.  Use ip address. */
-                return xstrdup(ntop);
+                return strdup(ntop);
         }
 
         /*
@@ -95,10 +87,10 @@ get_remote_hostname(int sock, int use_dns)
                 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
                     name, ntop);
                 freeaddrinfo(ai);
-                return xstrdup(ntop);
+                return strdup(ntop);
         }
 
-        /* Names are stores in lowercase. */
+        /* Names are stored in lowercase. */
         lowercase(name);
 
         /*
@@ -115,8 +107,8 @@ get_remote_hostname(int sock, int use_dns)
         hints.ai_socktype = SOCK_STREAM;
         if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
                 logit("reverse mapping checking getaddrinfo for %.700s "
-                    "[%s] failed - POSSIBLE BREAK-IN ATTEMPT!", name, ntop);
-                return xstrdup(ntop);
+                    "[%s] failed.", name, ntop);
+                return strdup(ntop);
         }
         /* Look for the address from the list of addresses. */
         for (ai = aitop; ai; ai = ai->ai_next) {
@@ -127,53 +119,13 @@ get_remote_hostname(int sock, int use_dns)
         }
         freeaddrinfo(aitop);
         /* If we reached the end of the list, the address was not there. */
-        if (!ai) {
+        if (ai == NULL) {
                 /* Address not found for the host name. */
                 logit("Address %.100s maps to %.600s, but this does not "
-                    "map back to the address - POSSIBLE BREAK-IN ATTEMPT!",
-                    ntop, name);
-                return xstrdup(ntop);
-        }
-        return xstrdup(name);
-}
-
-/*
- * If IP options are supported, make sure there are none (log and
- * disconnect them if any are found).  Basically we are worried about
- * source routing; it can be used to pretend you are somebody
- * (ip-address) you are not. That itself may be "almost acceptable"
- * under certain circumstances, but rhosts autentication is useless
- * if source routing is accepted. Notice also that if we just dropped
- * source routing here, the other side could use IP spoofing to do
- * rest of the interaction and could still bypass security.  So we
- * exit here if we detect any IP options.
- */
-/* IPv4 only */
-static void
-check_ip_options(int sock, char *ipaddr)
-{
-#ifdef IP_OPTIONS
-        u_char options[200];
-        char text[sizeof(options) * 3 + 1];
-        socklen_t option_size, i;
-        int ipproto;
-        struct protoent *ip;
-
-        if ((ip = getprotobyname("ip")) != NULL)
-                ipproto = ip->p_proto;
-        else
-                ipproto = IPPROTO_IP;
-        option_size = sizeof(options);
-        if (getsockopt(sock, ipproto, IP_OPTIONS, options,
-            &option_size) >= 0 && option_size != 0) {
-                text[0] = '\0';
-                for (i = 0; i < option_size; i++)
-                        snprintf(text + i*3, sizeof(text) - i*3,
-                            " %2.2x", options[i]);
-                fatal("Connection from %.100s with IP options:%.800s",
-                    ipaddr, text);
+                    "map back to the address.", ntop, name);
+                return strdup(ntop);
         }
-#endif /* IP_OPTIONS */
+        return strdup(name);
 }
 
 void
@@ -202,38 +154,6 @@ ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
 }
 
 /*
- * Return the canonical name of the host in the other side of the current
- * connection.  The host name is cached, so it is efficient to call this
- * several times.
- */
-
-const char *
-get_canonical_hostname(int use_dns)
-{
-        char *host;
-        static char *canonical_host_name = NULL;
-        static char *remote_ip = NULL;
-
-        /* Check if we have previously retrieved name with same option. */
-        if (use_dns && canonical_host_name != NULL)
-                return canonical_host_name;
-        if (!use_dns && remote_ip != NULL)
-                return remote_ip;
-
-        /* Get the real hostname if socket; otherwise return UNKNOWN. */
-        if (packet_connection_is_on_socket())
-                host = get_remote_hostname(packet_get_connection_in(), use_dns);
-        else
-                host = "UNKNOWN";
-
-        if (use_dns)
-                canonical_host_name = host;
-        else
-                remote_ip = host;
-        return host;
-}
-
-/*
  * Returns the local/remote IP-address/hostname of socket as a string.
  * The returned string must be freed.
  */
@@ -250,12 +170,10 @@ get_socket_address(int sock, int remote, int flags)
         memset(&addr, 0, sizeof(addr));
 
         if (remote) {
-                if (getpeername(sock, (struct sockaddr *)&addr, &addrlen)
-                    < 0)
+                if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) != 0)
                         return NULL;
         } else {
-                if (getsockname(sock, (struct sockaddr *)&addr, &addrlen)
-                    < 0)
+                if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) != 0)
                         return NULL;
         }
 
@@ -271,7 +189,7 @@ get_socket_address(int sock, int remote, int flags)
                 /* Get the address in ascii. */
                 if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
                     sizeof(ntop), NULL, 0, flags)) != 0) {
-                        error("get_socket_address: getnameinfo %d failed: %s",
+                        error("%s: getnameinfo %d failed: %s", __func__,
                             flags, ssh_gai_strerror(r));
                         return NULL;
                 }
@@ -316,7 +234,8 @@ get_local_name(int fd)
 
         /* Handle the case where we were passed a pipe */
         if (gethostname(myname, sizeof(myname)) == -1) {
-                verbose("get_local_name: gethostname: %s", strerror(errno));
+                verbose("%s: gethostname: %s", __func__, strerror(errno));
+                host = xstrdup("UNKNOWN");
         } else {
                 host = xstrdup(myname);
         }
@@ -324,51 +243,9 @@ get_local_name(int fd)
         return host;
 }
 
-void
-clear_cached_addr(void)
-{
-        free(canonical_host_ip);
-        canonical_host_ip = NULL;
-        cached_port = -1;
-}
-
-/*
- * Returns the IP-address of the remote host as a string.  The returned
- * string must not be freed.
- */
-
-const char *
-get_remote_ipaddr(void)
-{
-        /* Check whether we have cached the ipaddr. */
-        if (canonical_host_ip == NULL) {
-                if (packet_connection_is_on_socket()) {
-                        canonical_host_ip =
-                            get_peer_ipaddr(packet_get_connection_in());
-                        if (canonical_host_ip == NULL)
-                                cleanup_exit(255);
-                } else {
-                        /* If not on socket, return UNKNOWN. */
-                        canonical_host_ip = xstrdup("UNKNOWN");
-                }
-        }
-        return canonical_host_ip;
-}
-
-const char *
-get_remote_name_or_ip(u_int utmp_len, int use_dns)
-{
-        static const char *remote = "";
-        if (utmp_len > 0)
-                remote = get_canonical_hostname(use_dns);
-        if (utmp_len == 0 || strlen(remote) > utmp_len)
-                remote = get_remote_ipaddr();
-        return remote;
-}
-
 /* Returns the local/remote port for the socket. */
 
-int
+static int
 get_sock_port(int sock, int local)
 {
         struct sockaddr_storage from;
@@ -402,27 +279,11 @@ get_sock_port(int sock, int local)
         /* Return port number. */
         if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
             strport, sizeof(strport), NI_NUMERICSERV)) != 0)
-                fatal("get_sock_port: getnameinfo NI_NUMERICSERV failed: %s",
+                fatal("%s: getnameinfo NI_NUMERICSERV failed: %s", __func__,
                     ssh_gai_strerror(r));
         return atoi(strport);
 }
 
-/* Returns remote/local port number for the current connection. */
-
-static int
-get_port(int local)
-{
-        /*
-         * If the connection is not a socket, return 65535.  This is
-         * intentionally chosen to be an unprivileged port number.
-         */
-        if (!packet_connection_is_on_socket())
-                return 65535;
-
-        /* Get socket and return the port number. */
-        return get_sock_port(packet_get_connection_in(), local);
-}
-
 int
 get_peer_port(int sock)
 {
@@ -430,17 +291,7 @@ get_peer_port(int sock)
 }
 
 int
-get_remote_port(void)
-{
-        /* Cache to avoid getpeername() on a dead connection */
-        if (cached_port == -1)
-                cached_port = get_port(0);
-
-        return cached_port;
-}
-
-int
-get_local_port(void)
+get_local_port(int sock)
 {
-        return get_port(1);
+        return get_sock_port(sock, 1);
 }