=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/canohost.c,v retrieving revision 1.12.2.4 retrieving revision 1.13 diff -u -r1.12.2.4 -r1.13 --- src/usr.bin/ssh/canohost.c 2001/03/21 18:52:37 1.12.2.4 +++ src/usr.bin/ssh/canohost.c 2000/06/20 01:39:39 1.13 @@ -1,231 +1,211 @@ /* + * + * canohost.c + * * Author: Tatu Ylonen + * * Copyright (c) 1995 Tatu Ylonen , 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. * - * 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". */ #include "includes.h" -RCSID("$OpenBSD: canohost.c,v 1.12.2.4 2001/03/21 18:52:37 jason Exp $"); +RCSID("$OpenBSD: canohost.c,v 1.13 2000/06/20 01:39:39 markus Exp $"); #include "packet.h" #include "xmalloc.h" -#include "log.h" -#include "canohost.h" +#include "ssh.h" -void check_ip_options(int socket, char *ipaddr); - /* * 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, int reverse_mapping_check) +get_remote_hostname(int socket) { struct sockaddr_storage from; int i; socklen_t fromlen; struct addrinfo hints, *ai, *aitop; - char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST]; + 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) { + if (getpeername(socket, (struct sockaddr *) & from, &fromlen) < 0) { debug("getpeername failed: %.100s", strerror(errno)); fatal_cleanup(); } - if (from.ss_family == AF_INET) - check_ip_options(socket, ntop); - if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed"); - debug("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. */ - log("Could not reverse map address %.100s.", ntop); - return xstrdup(ntop); + 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); } - /* 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]); +check_ip_options: - if (!reverse_mapping_check) - return xstrdup(name); /* - * 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). + * 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. */ - 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); - return xstrdup(ntop); + /* 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); + } } - /* 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); - 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 */ -void -check_ip_options(int socket, char *ipaddr) -{ - u_char options[200]; - char text[sizeof(options) * 3 + 1]; - socklen_t option_size; - int i, 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, (void *)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]); - log("Connection from %.100s with IP options:%.800s", - ipaddr, text); - packet_disconnect("Connection from %.100s with IP options:%.800s", - ipaddr, text); - } -} - -/* * 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 reverse_mapping_check) +get_canonical_hostname() { static char *canonical_host_name = NULL; - static int reverse_mapping_checked = 0; - /* Check if we have previously retrieved name with same option. */ - if (canonical_host_name != NULL) { - if (reverse_mapping_checked != reverse_mapping_check) - xfree(canonical_host_name); - else - return canonical_host_name; - } + /* 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(), reverse_mapping_check); + canonical_host_name = get_remote_hostname(packet_get_connection_in()); else canonical_host_name = xstrdup("UNKNOWN"); - reverse_mapping_checked = reverse_mapping_check; return canonical_host_name; } /* - * Returns the remote IP-address of socket as a string. The returned - * string must be freed. + * Returns the IP-address of the remote host as a string. The returned + * string must not be freed. */ -char * -get_peer_ipaddr(int socket) +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("get_peer_ipaddr: getpeername failed: %.100s", strerror(errno)); - return NULL; + 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) { - error("get_peer_ipaddr: getnameinfo NI_NUMERICHOST failed"); - return NULL; - } - return xstrdup(ntop); -} + NULL, 0, NI_NUMERICHOST) != 0) + fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed"); -/* - * Returns the IP-address of the remote host as a string. The returned - * string must not be freed. - */ + canonical_host_ip = xstrdup(ntop); -const char * -get_remote_ipaddr() -{ - static char *canonical_host_ip = NULL; - - /* 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) - fatal_cleanup(); - } else { - /* If not on socket, return UNKNOWN. */ - canonical_host_ip = xstrdup("UNKNOWN"); - } - } + /* Return ip address string. */ return canonical_host_ip; }