+/* $OpenBSD: canohost.c,v 1.65 2009/05/27 06:31:25 andreas Exp $ */
/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * Functions for returning the canonical host name of the remote site.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ */
-canohost.c
+#include "includes.h"
-Author: Tatu Ylonen <ylo@cs.hut.fi>
+#include <sys/types.h>
+#include <sys/socket.h>
-Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- All rights reserved
+#include <netinet/in.h>
+#include <arpa/inet.h>
-Created: Sun Jul 2 17:52:22 1995 ylo
+#include <ctype.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
-Functions for returning the canonical host name of the remote site.
+#include "xmalloc.h"
+#include "packet.h"
+#include "log.h"
+#include "canohost.h"
+#include "misc.h"
-*/
+static void check_ip_options(int, char *);
+static char *canonical_host_ip = NULL;
+static int cached_port = -1;
-#include "includes.h"
-RCSID("$Id$");
+/*
+ * Return the canonical name of the host at the other end of the socket. The
+ * caller should free the returned string with xfree.
+ */
-#include "packet.h"
-#include "xmalloc.h"
-#include "ssh.h"
-
-/* Return the canonical name of the host at the other end of the socket.
- The caller should free the returned string with xfree. */
-
-char *get_remote_hostname(int socket)
-{
- struct sockaddr_in from;
- int fromlen, i;
- struct hostent *hp;
- char name[MAXHOSTNAMELEN];
-
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(socket, (struct sockaddr *)&from, &fromlen) < 0)
- {
- error("getpeername failed: %.100s", strerror(errno));
- strlcpy(name, "UNKNOWN", sizeof name);
- goto check_ip_options;
- }
-
- /* Map the IP address to a host name. */
- hp = gethostbyaddr((char *)&from.sin_addr, sizeof(struct in_addr),
- from.sin_family);
- if (hp)
- {
- /* Got host name, find canonic host name. */
- if (strchr(hp->h_name, '.') != 0)
- strlcpy(name, hp->h_name, sizeof(name));
- else if (hp->h_aliases != 0
- && hp->h_aliases[0] != 0
- && strchr(hp->h_aliases[0], '.') != 0)
- strlcpy(name, hp->h_aliases[0], sizeof(name));
- else
- strlcpy(name, hp->h_name, sizeof(name));
-
- /* Convert it to all lowercase (which is expected by the rest of this
- software). */
- for (i = 0; name[i]; i++)
- if (isupper(name[i]))
- name[i] = tolower(name[i]);
-
- /* Map it back to an IP address and check that the given address actually
- is an address of this host. This is necessary because anyone with
- access to a name server can define arbitrary names for an IP address.
- Mapping from name to IP address can be trusted better (but can still
- be fooled if the intruder has access to the name server of the
- domain). */
- hp = gethostbyname(name);
- if (!hp)
- {
- log("reverse mapping checking gethostbyname for %.700s failed - POSSIBLE BREAKIN ATTEMPT!", name);
- strlcpy(name, inet_ntoa(from.sin_addr), sizeof name);
- goto check_ip_options;
+static char *
+get_remote_hostname(int sock, int use_dns)
+{
+ struct sockaddr_storage from;
+ int i;
+ socklen_t fromlen;
+ struct addrinfo hints, *ai, *aitop;
+ char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST];
+
+ /* Get IP address of client. */
+ fromlen = sizeof(from);
+ memset(&from, 0, sizeof(from));
+ if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
+ debug("getpeername failed: %.100s", strerror(errno));
+ cleanup_exit(255);
}
- /* Look for the address from the list of addresses. */
- for (i = 0; hp->h_addr_list[i]; i++)
- if (memcmp(hp->h_addr_list[i], &from.sin_addr, sizeof(from.sin_addr))
- == 0)
- break;
- /* If we reached the end of the list, the address was not there. */
- if (!hp->h_addr_list[i])
- {
- /* Address not found for the host name. */
- log("Address %.100s maps to %.600s, but this does not map back to the address - POSSIBLE BREAKIN ATTEMPT!",
- inet_ntoa(from.sin_addr), name);
- strlcpy(name, inet_ntoa(from.sin_addr), sizeof name);
- goto check_ip_options;
+
+ 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);
}
- /* Address was found for the host name. We accept the host name. */
- }
- else
- {
- /* Host name not found. Use ascii representation of the address. */
- strlcpy(name, inet_ntoa(from.sin_addr), sizeof name);
- log("Could not reverse map address %.100s.", name);
- }
-
- check_ip_options:
-
- /* If IP options are supported, make sure there are none (log and clear
- 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. */
- {
- unsigned char options[200], *ucp;
- char text[1024], *cp;
- int option_size, ipproto;
- struct protoent *ip;
-
- if ((ip = getprotobyname("ip")) != NULL)
- ipproto = ip->p_proto;
- else
- ipproto = IPPROTO_IP;
- option_size = sizeof(options);
- if (getsockopt(0, ipproto, IP_OPTIONS, (char *)options,
- &option_size) >= 0 && option_size != 0)
- {
- cp = text;
- /* Note: "text" buffer must be at least 3x as big as options. */
- for (ucp = options; option_size > 0; ucp++, option_size--, cp += 3)
- sprintf(cp, " %2.2x", *ucp);
- log("Connection from %.100s with IP options:%.800s",
- inet_ntoa(from.sin_addr), text);
- packet_disconnect("Connection from %.100s with IP options:%.800s",
- inet_ntoa(from.sin_addr), text);
- }
- }
-
- return xstrdup(name);
-}
-
-static char *canonical_host_name = NULL;
-static char *canonical_host_ip = NULL;
-/* 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. */
+ /*
+ * if reverse lookup result looks like a numeric hostname,
+ * someone is trying to trick us by PTR record like following:
+ * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = SOCK_DGRAM; /*dummy*/
+ hints.ai_flags = AI_NUMERICHOST;
+ if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
+ logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
+ name, ntop);
+ freeaddrinfo(ai);
+ return xstrdup(ntop);
+ }
+
+ /*
+ * Convert it to all lowercase (which is expected by the rest
+ * of this software).
+ */
+ for (i = 0; name[i]; i++)
+ if (isupper(name[i]))
+ name[i] = (char)tolower(name[i]);
+ /*
+ * Map it back to an IP address and check that the given
+ * address actually is an address of this host. This is
+ * necessary because anyone with access to a name server can
+ * define arbitrary names for an IP address. Mapping from
+ * name to IP address can be trusted better (but can still be
+ * fooled if the intruder has access to the name server of
+ * the domain).
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = from.ss_family;
+ 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);
+ }
+ /* Look for the address from the list of addresses. */
+ for (ai = aitop; ai; ai = ai->ai_next) {
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
+ sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
+ (strcmp(ntop, ntop2) == 0))
+ break;
+ }
+ freeaddrinfo(aitop);
+ /* If we reached the end of the list, the address was not there. */
+ if (!ai) {
+ /* 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;
+ u_int 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);
+ }
+#endif /* IP_OPTIONS */
+}
+
+void
+ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
+{
+ struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;
+ struct sockaddr_in *a4 = (struct sockaddr_in *)addr;
+ struct in_addr inaddr;
+ u_int16_t port;
+
+ if (addr->ss_family != AF_INET6 ||
+ !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
+ return;
+
+ debug3("Normalising mapped IPv4 in IPv6 address");
+
+ memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
+ port = a6->sin6_port;
+
+ memset(addr, 0, sizeof(*a4));
-const char *get_canonical_hostname()
+ a4->sin_family = AF_INET;
+ *len = sizeof(*a4);
+ memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));
+ a4->sin_port = port;
+}
+
+/*
+ * 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)
{
- /* Check if we have previously retrieved this same name. */
- if (canonical_host_name != NULL)
- return canonical_host_name;
+ 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.
+ */
+static char *
+get_socket_address(int sock, int remote, int flags)
+{
+ struct sockaddr_storage addr;
+ socklen_t addrlen;
+ char ntop[NI_MAXHOST];
+ int r;
+
+ /* Get IP address of client. */
+ addrlen = sizeof(addr);
+ memset(&addr, 0, sizeof(addr));
+
+ if (remote) {
+ if (getpeername(sock, (struct sockaddr *)&addr, &addrlen)
+ < 0)
+ return NULL;
+ } else {
+ if (getsockname(sock, (struct sockaddr *)&addr, &addrlen)
+ < 0)
+ return NULL;
+ }
- /* Get the real hostname if socket; otherwise return UNKNOWN. */
- if (packet_get_connection_in() == packet_get_connection_out())
- canonical_host_name = get_remote_hostname(packet_get_connection_in());
- else
- canonical_host_name = xstrdup("UNKNOWN");
+ /* Work around Linux IPv6 weirdness */
+ if (addr.ss_family == AF_INET6)
+ addrlen = sizeof(struct sockaddr_in6);
- return canonical_host_name;
+ ipv64_normalise_mapped(&addr, &addrlen);
+
+ /* 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", flags,
+ ssh_gai_strerror(r));
+ return NULL;
+ }
+ return xstrdup(ntop);
}
-/* Returns the IP-address of the remote host as a string. The returned
- string need not be freed. */
+char *
+get_peer_ipaddr(int sock)
+{
+ char *p;
+
+ if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
+ return p;
+ return xstrdup("UNKNOWN");
+}
-const char *get_remote_ipaddr()
+char *
+get_local_ipaddr(int sock)
{
- struct sockaddr_in from;
- int fromlen, socket;
+ char *p;
- /* Check if we have previously retrieved this same name. */
- if (canonical_host_ip != NULL)
- return canonical_host_ip;
+ if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
+ return p;
+ return xstrdup("UNKNOWN");
+}
- /* If not a socket, return UNKNOWN. */
- if (packet_get_connection_in() != packet_get_connection_out())
- {
- canonical_host_ip = xstrdup("UNKNOWN");
- return canonical_host_ip;
- }
+char *
+get_local_name(int sock)
+{
+ return get_socket_address(sock, 0, NI_NAMEREQD);
+}
- /* Get client socket. */
- socket = packet_get_connection_in();
+void
+clear_cached_addr(void)
+{
+ if (canonical_host_ip != NULL) {
+ xfree(canonical_host_ip);
+ canonical_host_ip = NULL;
+ }
+ cached_port = -1;
+}
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(socket, (struct sockaddr *)&from, &fromlen) < 0)
- {
- error("getpeername failed: %.100s", strerror(errno));
- return NULL;
- }
+/*
+ * Returns the IP-address of the remote host as a string. The returned
+ * string must not be freed.
+ */
- /* Get the IP address in ascii. */
- canonical_host_ip = xstrdup(inet_ntoa(from.sin_addr));
+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;
+}
- /* Return ip address string. */
- 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 port of the peer of the socket. */
+/* Returns the local/remote port for the socket. */
-int get_peer_port(int sock)
+int
+get_sock_port(int sock, int local)
{
- struct sockaddr_in from;
- int fromlen;
+ struct sockaddr_storage from;
+ socklen_t fromlen;
+ char strport[NI_MAXSERV];
+ int r;
+
+ /* Get IP address of client. */
+ fromlen = sizeof(from);
+ memset(&from, 0, sizeof(from));
+ if (local) {
+ if (getsockname(sock, (struct sockaddr *)&from, &fromlen) < 0) {
+ error("getsockname failed: %.100s", strerror(errno));
+ return 0;
+ }
+ } else {
+ if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
+ debug("getpeername failed: %.100s", strerror(errno));
+ return -1;
+ }
+ }
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0)
- {
- error("getpeername failed: %.100s", strerror(errno));
- return 0;
- }
+ /* Work around Linux IPv6 weirdness */
+ if (from.ss_family == AF_INET6)
+ fromlen = sizeof(struct sockaddr_in6);
- /* Return port number. */
- return ntohs(from.sin_port);
+ /* 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",
+ ssh_gai_strerror(r));
+ return atoi(strport);
}
-/* Returns the port number of the remote host. */
+/* 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_remote_port()
+int
+get_peer_port(int sock)
{
- int socket;
+ return get_sock_port(sock, 0);
+}
- /* If the connection is not a socket, return 65535. This is intentionally
- chosen to be an unprivileged port number. */
- if (packet_get_connection_in() != packet_get_connection_out())
- return 65535;
+int
+get_remote_port(void)
+{
+ /* Cache to avoid getpeername() on a dead connection */
+ if (cached_port == -1)
+ cached_port = get_port(0);
- /* Get client socket. */
- socket = packet_get_connection_in();
+ return cached_port;
+}
- /* Get and return the peer port number. */
- return get_peer_port(socket);
+int
+get_local_port(void)
+{
+ return get_port(1);
}
andersk / openssh.git / blobdiff