=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/canohost.c,v retrieving revision 1.5 retrieving revision 1.6 diff -u -r1.5 -r1.6 --- src/usr.bin/ssh/canohost.c 1999/11/15 00:42:01 1.5 +++ src/usr.bin/ssh/canohost.c 1999/11/23 22:25:53 1.6 @@ -14,220 +14,215 @@ */ #include "includes.h" -RCSID("$Id: canohost.c,v 1.5 1999/11/15 00:42:01 markus Exp $"); +RCSID("$Id: canohost.c,v 1.6 1999/11/23 22:25:53 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. +/* 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) +char * +get_remote_hostname(int socket) { - struct sockaddr_in from; - int fromlen, i; - struct hostent *hp; - char name[MAXHOSTNAMELEN]; + 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) - { - debug("getpeername failed: %.100s", strerror(errno)); - fatal_cleanup(); - } - - /* 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]); + /* 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(); + } + /* 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)); - /* 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; + /* 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; + } + /* 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; + } + /* 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); } - /* 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]) + +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. */ { - /* 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; + 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); + } } - /* 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 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. */ - { - 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); + 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 + connection. The host name is cached, so it is efficient to call this several times. */ -const char *get_canonical_hostname() +const char * +get_canonical_hostname() { - /* Check if we have previously retrieved this same name. */ - if (canonical_host_name != NULL) - 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_get_connection_in() == packet_get_connection_out()) - canonical_host_name = get_remote_hostname(packet_get_connection_in()); - else - canonical_host_name = xstrdup("UNKNOWN"); + /* 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"); - return canonical_host_name; + return canonical_host_name; } /* Returns the IP-address of the remote host as a string. The returned string need not be freed. */ -const char *get_remote_ipaddr() +const char * +get_remote_ipaddr() { - struct sockaddr_in from; - int fromlen, socket; + struct sockaddr_in from; + int fromlen, socket; - /* Check if we have previously retrieved this same name. */ - if (canonical_host_ip != NULL) - return canonical_host_ip; + /* Check if we have previously retrieved this same name. */ + if (canonical_host_ip != NULL) + return canonical_host_ip; - /* If not a socket, return UNKNOWN. */ - if (packet_get_connection_in() != packet_get_connection_out()) - { - canonical_host_ip = xstrdup("UNKNOWN"); - return canonical_host_ip; - } + /* If not a socket, return UNKNOWN. */ + if (packet_get_connection_in() != packet_get_connection_out()) { + canonical_host_ip = xstrdup("UNKNOWN"); + return canonical_host_ip; + } + /* Get client socket. */ + socket = packet_get_connection_in(); - /* 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. */ + canonical_host_ip = xstrdup(inet_ntoa(from.sin_addr)); - /* 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. */ - canonical_host_ip = xstrdup(inet_ntoa(from.sin_addr)); - - /* Return ip address string. */ - return canonical_host_ip; + /* Return ip address string. */ + return canonical_host_ip; } /* Returns the port of the peer of the socket. */ -int get_peer_port(int sock) +int +get_peer_port(int sock) { - struct sockaddr_in from; - int fromlen; + struct sockaddr_in from; + int fromlen; - /* 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)); - fatal_cleanup(); - } - - /* Return port number. */ - return ntohs(from.sin_port); + /* 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)); + fatal_cleanup(); + } + /* Return port number. */ + return ntohs(from.sin_port); } /* Returns the port number of the remote host. */ -int get_remote_port() +int +get_remote_port() { - int socket; + int socket; - /* 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; + /* 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; - /* Get client socket. */ - socket = packet_get_connection_in(); + /* Get client socket. */ + socket = packet_get_connection_in(); - /* Get and return the peer port number. */ - return get_peer_port(socket); + /* Get and return the peer port number. */ + return get_peer_port(socket); }