diff options
author | markm <markm@FreeBSD.org> | 2000-02-24 14:29:47 +0000 |
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committer | markm <markm@FreeBSD.org> | 2000-02-24 14:29:47 +0000 |
commit | fc557ff7d97438559e69347575f5aa8ef03a5f50 (patch) | |
tree | c90ea5392aa03e7619696143bde781f2bf5c0dff /crypto/openssh/canohost.c | |
download | FreeBSD-src-fc557ff7d97438559e69347575f5aa8ef03a5f50.zip FreeBSD-src-fc557ff7d97438559e69347575f5aa8ef03a5f50.tar.gz |
Vendor import of OpenSSH.
Diffstat (limited to 'crypto/openssh/canohost.c')
-rw-r--r-- | crypto/openssh/canohost.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/crypto/openssh/canohost.c b/crypto/openssh/canohost.c new file mode 100644 index 0000000..fcf743c --- /dev/null +++ b/crypto/openssh/canohost.c @@ -0,0 +1,274 @@ +/* + * + * canohost.c + * + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * + * Created: Sun Jul 2 17:52:22 1995 ylo + * + * Functions for returning the canonical host name of the remote site. + * + */ + +#include "includes.h" +RCSID("$Id: canohost.c,v 1.11 2000/01/04 13:41:32 markus Exp $"); + +#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_storage from; + int i; + socklen_t fromlen; + struct addrinfo hints, *ai, *aitop; + char name[MAXHOSTNAMELEN]; + char 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) { + debug("getpeername failed: %.100s", strerror(errno)); + fatal_cleanup(); + } + if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop), + NULL, 0, NI_NUMERICHOST) != 0) + fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed"); + + /* 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); + } + +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. + */ + /* 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(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", + ntop, text); + packet_disconnect("Connection from %.100s with IP options:%.800s", + ntop, text); + } + } + + return xstrdup(name); +} + +/* + * 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() +{ + static char *canonical_host_name = NULL; + + /* Check if we have previously retrieved this same name. */ + if (canonical_host_name != NULL) + return canonical_host_name; + + /* 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()); + else + canonical_host_name = xstrdup("UNKNOWN"); + + return canonical_host_name; +} + +/* + * Returns the IP-address of the remote host as a string. The returned + * string must not be freed. + */ + +const char * +get_remote_ipaddr() +{ + static char *canonical_host_ip = NULL; + struct sockaddr_storage from; + socklen_t fromlen; + int socket; + char ntop[NI_MAXHOST]; + + /* Check whether we have chached the name. */ + if (canonical_host_ip != NULL) + return canonical_host_ip; + + /* If not a socket, return UNKNOWN. */ + if (!packet_connection_is_on_socket()) { + canonical_host_ip = xstrdup("UNKNOWN"); + return canonical_host_ip; + } + /* 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(); + } + /* 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"); + + canonical_host_ip = xstrdup(ntop); + + /* Return ip address string. */ + return canonical_host_ip; +} + +/* Returns the local/remote port for the socket. */ + +int +get_sock_port(int sock, int local) +{ + struct sockaddr_storage from; + socklen_t fromlen; + char strport[NI_MAXSERV]; + + /* 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)); + fatal_cleanup(); + } + } + /* 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"); + return atoi(strport); +} + +/* Returns remote/local port number for the current connection. */ + +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) +{ + return get_sock_port(sock, 0); +} + +int +get_remote_port() +{ + return get_port(0); +} + +int +get_local_port() +{ + return get_port(1); +} |