+/* $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
*/
#include "includes.h"
-RCSID("$OpenBSD: canohost.c,v 1.16 2000/10/21 17:04:22 markus Exp $");
-#include "packet.h"
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
#include "xmalloc.h"
-#include "ssh.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;
/*
* 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)
+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[MAXHOSTNAMELEN];
- char ntop[NI_MAXHOST], ntop2[NI_MAXHOST];
+ 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(socket, (struct sockaddr *) & from, &fromlen) < 0) {
+ if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
- fatal_cleanup();
+ cleanup_exit(255);
}
-#ifdef IPV4_IN_IPV6
- if (from.ss_family == AF_INET6) {
- struct sockaddr_in6 *from6 = (struct sockaddr_in6 *)&from;
-
- /* Detect IPv4 in IPv6 mapped address and convert it to */
- /* plain (AF_INET) IPv4 address */
- if (IN6_IS_ADDR_V4MAPPED(&from6->sin6_addr)) {
- struct sockaddr_in *from4 = (struct sockaddr_in *)&from;
- struct in_addr addr;
- u_int16_t port;
-
- memcpy(&addr, ((char *)&from6->sin6_addr) + 12, sizeof(addr));
- port = from6->sin6_port;
-
- memset(&from, 0, sizeof(from));
-
- from4->sin_family = AF_INET;
- memcpy(&from4->sin_addr, &addr, sizeof(addr));
- from4->sin_port = port;
- }
- }
-#endif
+ 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)
+ 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) {
- /* Got host name. */
- name[sizeof(name) - 1] = '\0';
- /*
- * 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).
- */
- memset(&hints, 0, sizeof(hints));
- hints.ai_family = from.ss_family;
- hints.ai_socktype = SOCK_STREAM;
- if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
- log("reverse mapping checking getaddrinfo for %.700s failed - POSSIBLE BREAKIN ATTEMPT!", name);
- strlcpy(name, ntop, sizeof name);
- goto check_ip_options;
- }
- /* 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. */
- log("Address %.100s maps to %.600s, but this does not map back to the address - POSSIBLE BREAKIN ATTEMPT!",
- ntop, name);
- strlcpy(name, ntop, sizeof name);
- goto check_ip_options;
- }
- /* 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, ntop, sizeof name);
- log("Could not reverse map address %.100s.", name);
+ NULL, 0, NI_NAMEREQD) != 0) {
+ /* Host name not found. Use ip address. */
+ return xstrdup(ntop);
}
-check_ip_options:
-
/*
- * 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.
+ * 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
*/
- /* IP options -- IPv4 only */
- if (from.ss_family == AF_INET) {
- unsigned char options[200], *ucp;
- char text[1024], *cp;
- socklen_t option_size;
- int ipproto;
- struct protoent *ip;
-
- if ((ip = getprotobyname("ip")) != NULL)
- ipproto = ip->p_proto;
- else
- ipproto = IPPROTO_IP;
- option_size = sizeof(options);
- if (getsockopt(socket, 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",
- ntop, text);
- packet_disconnect("Connection from %.100s with IP options:%.800s",
- ntop, text);
- }
+ 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));
+
+ 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
*/
const char *
-get_canonical_hostname()
+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 this same name. */
- if (canonical_host_name != 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())
- canonical_host_name = get_remote_hostname(packet_get_connection_in());
+ host = get_remote_hostname(packet_get_connection_in(), use_dns);
else
- canonical_host_name = xstrdup("UNKNOWN");
+ host = "UNKNOWN";
- return canonical_host_name;
+ if (use_dns)
+ canonical_host_name = host;
+ else
+ remote_ip = host;
+ return host;
}
/*
- * Returns the IP-address of the remote host as a string. The returned
- * string must not be freed.
+ * Returns the local/remote IP-address/hostname of socket as a string.
+ * The returned string must be freed.
*/
-
-const char *
-get_remote_ipaddr()
+static char *
+get_socket_address(int sock, int remote, int flags)
{
- static char *canonical_host_ip = NULL;
- struct sockaddr_storage from;
- socklen_t fromlen;
- int socket;
+ struct sockaddr_storage addr;
+ socklen_t addrlen;
char ntop[NI_MAXHOST];
+ int r;
- /* Check whether we have chached the name. */
- if (canonical_host_ip != NULL)
- return canonical_host_ip;
+ /* Get IP address of client. */
+ addrlen = sizeof(addr);
+ memset(&addr, 0, sizeof(addr));
- /* If not a socket, return UNKNOWN. */
- if (!packet_connection_is_on_socket()) {
- canonical_host_ip = xstrdup("UNKNOWN");
- return canonical_host_ip;
+ if (remote) {
+ if (getpeername(sock, (struct sockaddr *)&addr, &addrlen)
+ < 0)
+ return NULL;
+ } else {
+ if (getsockname(sock, (struct sockaddr *)&addr, &addrlen)
+ < 0)
+ return NULL;
}
- /* Get client socket. */
- socket = packet_get_connection_in();
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(socket, (struct sockaddr *) & from, &fromlen) < 0) {
- debug("getpeername failed: %.100s", strerror(errno));
- fatal_cleanup();
+ /* Work around Linux IPv6 weirdness */
+ if (addr.ss_family == AF_INET6)
+ addrlen = sizeof(struct sockaddr_in6);
+
+ 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;
}
- /* Get the IP address in ascii. */
- if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
- NULL, 0, NI_NUMERICHOST) != 0)
- fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed");
+ return xstrdup(ntop);
+}
+
+char *
+get_peer_ipaddr(int sock)
+{
+ char *p;
+
+ if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
+ return p;
+ return xstrdup("UNKNOWN");
+}
+
+char *
+get_local_ipaddr(int sock)
+{
+ char *p;
+
+ if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
+ return p;
+ return xstrdup("UNKNOWN");
+}
+
+char *
+get_local_name(int sock)
+{
+ return get_socket_address(sock, 0, NI_NAMEREQD);
+}
+
+void
+clear_cached_addr(void)
+{
+ if (canonical_host_ip != NULL) {
+ xfree(canonical_host_ip);
+ canonical_host_ip = NULL;
+ }
+ cached_port = -1;
+}
- canonical_host_ip = xstrdup(ntop);
+/*
+ * Returns the IP-address of the remote host as a string. The returned
+ * string must not be freed.
+ */
- /* Return ip address string. */
+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
struct sockaddr_storage from;
socklen_t fromlen;
char strport[NI_MAXSERV];
+ int r;
/* Get IP address of client. */
fromlen = sizeof(from);
return 0;
}
} else {
- if (getpeername(sock, (struct sockaddr *) & from, &fromlen) < 0) {
+ if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
- fatal_cleanup();
+ return -1;
}
}
+
+ /* Work around Linux IPv6 weirdness */
+ if (from.ss_family == AF_INET6)
+ fromlen = sizeof(struct sockaddr_in6);
+
/* Return port number. */
- if (getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
- strport, sizeof(strport), NI_NUMERICSERV) != 0)
- fatal("get_sock_port: getnameinfo NI_NUMERICSERV failed");
+ 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 remote/local port number for the current connection. */
-int
+static int
get_port(int local)
{
/*
}
int
-get_remote_port()
+get_remote_port(void)
{
- return get_port(0);
+ /* Cache to avoid getpeername() on a dead connection */
+ if (cached_port == -1)
+ cached_port = get_port(0);
+
+ return cached_port;
}
int
-get_local_port()
+get_local_port(void)
{
return get_port(1);
}