diff options
Diffstat (limited to 'canohost.c')
| -rw-r--r-- | canohost.c | 79 |
1 files changed, 47 insertions, 32 deletions
@@ -14,14 +14,16 @@ */ #include "includes.h" -RCSID("$Id: canohost.c,v 1.3 1999/11/24 13:26:22 damien Exp $"); +RCSID("$Id: canohost.c,v 1.4 1999/11/25 00:54:58 damien 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. */ +/* + * 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) @@ -52,19 +54,23 @@ get_remote_hostname(int socket) else strlcpy(name, hp->h_name, sizeof(name)); - /* Convert it to all lowercase (which is expected by the - rest of this software). */ + /* + * 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). */ + /* + * 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); @@ -76,8 +82,10 @@ get_remote_hostname(int socket) 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 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!", @@ -94,16 +102,17 @@ get_remote_hostname(int socket) 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 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; @@ -134,9 +143,11 @@ check_ip_options: 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. */ +/* + * 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() @@ -154,8 +165,10 @@ get_canonical_hostname() return canonical_host_name; } -/* Returns the IP-address of the remote host as a string. The returned - string need not be freed. */ +/* + * Returns the IP-address of the remote host as a string. The returned + * string need not be freed. + */ const char * get_remote_ipaddr() @@ -163,7 +176,7 @@ get_remote_ipaddr() struct sockaddr_in from; int fromlen, socket; - /* Check if we have previously retrieved this same name. */ + /* Check whether we have chached the name. */ if (canonical_host_ip != NULL) return canonical_host_ip; @@ -215,8 +228,10 @@ get_remote_port() { int socket; - /* If the connection is not a socket, return 65535. This is - intentionally chosen to be an unprivileged port number. */ + /* + * 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; |