X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/96c41595f1ca0665084d7f54ae6d13e0ad270d03..aff4a802a9e792b9bd2215c6ffb9c2864cb4ba24:/openssh/canohost.c diff --git a/openssh/canohost.c b/openssh/canohost.c index 6e6a045..670f23b 100644 --- a/openssh/canohost.c +++ b/openssh/canohost.c @@ -1,3 +1,4 @@ +/* $OpenBSD: canohost.c,v 1.62 2007/12/27 14:22:08 dtucker Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -12,12 +13,28 @@ */ #include "includes.h" -RCSID("$OpenBSD: canohost.c,v 1.27 2001/06/23 15:12:17 itojun Exp $"); -#include "packet.h" +#include +#include +#include /* for MAXHOSTNAMELEN */ + +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include + #include "xmalloc.h" +#include "packet.h" #include "log.h" #include "canohost.h" +#include "misc.h" static void check_ip_options(int, char *); @@ -27,7 +44,7 @@ static void check_ip_options(int, char *); */ static char * -get_remote_hostname(int socket, int reverse_mapping_check) +get_remote_hostname(int sock, int use_dns) { struct sockaddr_storage from; int i; @@ -38,60 +55,56 @@ get_remote_hostname(int socket, int reverse_mapping_check) /* 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; + if (from.ss_family == AF_INET) + check_ip_options(sock, ntop); - memset(&from, 0, sizeof(from)); + ipv64_normalise_mapped(&from, &fromlen); - 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(socket, ntop); + 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) { + NULL, 0, NI_NAMEREQD) != 0) { /* Host name not found. Use ip address. */ - log("Could not reverse map address %.100s.", ntop); return xstrdup(ntop); } - /* Got host name. */ - name[sizeof(name) - 1] = '\0'; + /* + * 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 + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_socktype = SOCK_DGRAM; /*dummy*/ + hints.ai_flags = AI_NUMERICHOST; + if (getaddrinfo(name, "0", &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] = tolower(name[i]); - - if (!reverse_mapping_check) - return xstrdup(name); + 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 @@ -105,8 +118,8 @@ get_remote_hostname(int socket, int reverse_mapping_check) 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); + 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. */ @@ -120,8 +133,8 @@ get_remote_hostname(int socket, int reverse_mapping_check) /* 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!", + logit("Address %.100s maps to %.600s, but this does not " + "map back to the address - POSSIBLE BREAK-IN ATTEMPT!", ntop, name); return xstrdup(ntop); } @@ -141,12 +154,14 @@ get_remote_hostname(int socket, int reverse_mapping_check) */ /* IPv4 only */ static void -check_ip_options(int socket, char *ipaddr) +check_ip_options(int sock, char *ipaddr) { +#ifdef IP_OPTIONS u_char options[200]; char text[sizeof(options) * 3 + 1]; socklen_t option_size; - int i, ipproto; + u_int i; + int ipproto; struct protoent *ip; if ((ip = getprotobyname("ip")) != NULL) @@ -154,17 +169,41 @@ check_ip_options(int socket, char *ipaddr) else ipproto = IPPROTO_IP; option_size = sizeof(options); - if (getsockopt(socket, ipproto, IP_OPTIONS, (void *)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]); - log("Connection from %.100s with IP options:%.800s", - ipaddr, text); - packet_disconnect("Connection from %.100s with IP options:%.800s", + 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; } /* @@ -174,85 +213,97 @@ check_ip_options(int socket, char *ipaddr) */ const char * -get_canonical_hostname(int reverse_mapping_check) +get_canonical_hostname(int use_dns) { + char *host; static char *canonical_host_name = NULL; - static int reverse_mapping_checked = 0; + static char *remote_ip = NULL; /* 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; - } + 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(), reverse_mapping_check); + host = get_remote_hostname(packet_get_connection_in(), use_dns); else - canonical_host_name = xstrdup("UNKNOWN"); + host = "UNKNOWN"; - reverse_mapping_checked = reverse_mapping_check; - return canonical_host_name; + if (use_dns) + canonical_host_name = host; + else + remote_ip = host; + return host; } /* - * Returns the remote IP-address of socket as a string. The returned - * string must be freed. + * Returns the local/remote IP-address/hostname of socket as a string. + * The returned string must be freed. */ static char * -get_socket_address(int socket, int remote, int flags) +get_socket_address(int sock, int remote, int flags) { struct sockaddr_storage addr; socklen_t addrlen; char ntop[NI_MAXHOST]; + int r; /* Get IP address of client. */ addrlen = sizeof(addr); memset(&addr, 0, sizeof(addr)); if (remote) { - if (getpeername(socket, (struct sockaddr *)&addr, &addrlen) - < 0) { - debug("get_socket_ipaddr: getpeername failed: %.100s", - strerror(errno)); + if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) + < 0) return NULL; - } } else { - if (getsockname(socket, (struct sockaddr *)&addr, &addrlen) - < 0) { - debug("get_socket_ipaddr: getsockname failed: %.100s", - strerror(errno)); + if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) + < 0) return NULL; - } } + + /* 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 (getnameinfo((struct sockaddr *)&addr, addrlen, ntop, sizeof(ntop), - NULL, 0, flags) != 0) { - error("get_socket_ipaddr: getnameinfo %d failed", flags); + 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; } return xstrdup(ntop); } char * -get_peer_ipaddr(int socket) +get_peer_ipaddr(int sock) { - return get_socket_address(socket, 1, NI_NUMERICHOST); + char *p; + + if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL) + return p; + return xstrdup("UNKNOWN"); } char * -get_local_ipaddr(int socket) +get_local_ipaddr(int sock) { - return get_socket_address(socket, 0, NI_NUMERICHOST); + char *p; + + if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL) + return p; + return xstrdup("UNKNOWN"); } char * -get_local_name(int socket) +get_local_name(int sock) { - return get_socket_address(socket, 0, NI_NAMEREQD); + return get_socket_address(sock, 0, NI_NAMEREQD); } /* @@ -261,7 +312,7 @@ get_local_name(int socket) */ const char * -get_remote_ipaddr() +get_remote_ipaddr(void) { static char *canonical_host_ip = NULL; @@ -271,7 +322,7 @@ get_remote_ipaddr() canonical_host_ip = get_peer_ipaddr(packet_get_connection_in()); if (canonical_host_ip == NULL) - fatal_cleanup(); + cleanup_exit(255); } else { /* If not on socket, return UNKNOWN. */ canonical_host_ip = xstrdup("UNKNOWN"); @@ -281,11 +332,11 @@ get_remote_ipaddr() } const char * -get_remote_name_or_ip(u_int utmp_len, int reverse_mapping_check) +get_remote_name_or_ip(u_int utmp_len, int use_dns) { static const char *remote = ""; if (utmp_len > 0) - remote = get_canonical_hostname(reverse_mapping_check); + remote = get_canonical_hostname(use_dns); if (utmp_len == 0 || strlen(remote) > utmp_len) remote = get_remote_ipaddr(); return remote; @@ -299,6 +350,7 @@ get_sock_port(int sock, int local) struct sockaddr_storage from; socklen_t fromlen; char strport[NI_MAXSERV]; + int r; /* Get IP address of client. */ fromlen = sizeof(from); @@ -309,15 +361,21 @@ get_sock_port(int sock, int local) 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); } @@ -344,13 +402,49 @@ get_peer_port(int sock) } int -get_remote_port() +get_remote_port(void) { - return get_port(0); + static int port = -1; + + /* Cache to avoid getpeername() on a dead connection */ + if (port == -1) + port = get_port(0); + + return port; } int -get_local_port() +get_local_port(void) { return get_port(1); } + +void +resolve_localhost(char **host) +{ + struct hostent *hostinfo; + + hostinfo = gethostbyname(*host); + if (hostinfo == NULL || hostinfo->h_name == NULL) { + debug("gethostbyname(%s) failed", *host); + return; + } + if (hostinfo->h_addrtype == AF_INET) { + struct in_addr addr; + addr = *(struct in_addr *)(hostinfo->h_addr); + if (ntohl(addr.s_addr) == INADDR_LOOPBACK) { + char buf[MAXHOSTNAMELEN]; + if (gethostname(buf, sizeof(buf)) < 0) { + debug("gethostname() failed"); + return; + } + hostinfo = gethostbyname(buf); + xfree(*host); + if (hostinfo == NULL || hostinfo->h_name == NULL) { + *host = xstrdup(buf); + } else { + *host = xstrdup(hostinfo->h_name); + } + } + } +}