packetstorm sync

1 files changed, 356 insertions, 0 deletions

diff --git a/other/ssharp/canohost.c b/other/ssharp/canohost.c
new file mode 100644
index 0000000..5d345eb
--- /dev/null
+++ b/other/ssharp/canohost.c
@@ -0,0 +1,356 @@
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * 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 1.26 2001/04/18 14:15:00 markus Exp $");
+
+#include "packet.h"
+#include "xmalloc.h"
+#include "log.h"
+#include "canohost.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)
+{
+        struct sockaddr_storage from;
+        int i;
+        socklen_t fromlen;
+        struct addrinfo hints, *ai, *aitop;
+        char name[NI_MAXHOST], 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();
+        }
+#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;
+
+                        memset(&from, 0, sizeof(from));
+
+                        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 (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
+             NULL, 0, NI_NUMERICHOST) != 0)
+                fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed");
+
+        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) {
+                /* 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';
+        /*
+         * 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);
+        /*
+         * 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);
+                return xstrdup(ntop);
+        }
+        /* 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)
+{
+        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;
+        }
+
+        /* 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);
+        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.
+ */
+char *
+get_socket_address(int socket, int remote, int flags)
+{
+        struct sockaddr_storage addr;
+        socklen_t addrlen;
+        char ntop[NI_MAXHOST];
+
+        /* 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));
+                        return NULL;
+                }
+        } else {
+                if (getsockname(socket, (struct sockaddr *)&addr, &addrlen)
+                    < 0) {
+                        debug("get_socket_ipaddr: getsockname failed: %.100s",
+                            strerror(errno));
+                        return NULL;
+                }
+        }
+        /* 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);
+                return NULL;
+        }
+        return xstrdup(ntop);
+}
+
+char *
+get_peer_ipaddr(int socket)
+{
+        return get_socket_address(socket, 1, NI_NUMERICHOST);
+}
+
+char *
+get_local_ipaddr(int socket)
+{
+        return get_socket_address(socket, 0, NI_NUMERICHOST);
+}
+
+char *
+get_local_name(int socket)
+{
+        return get_socket_address(socket, 0, NI_NAMEREQD);
+}
+
+/*
+ * 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;
+
+        /* 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 canonical_host_ip;
+}
+
+const char *
+get_remote_name_or_ip(u_int utmp_len, int reverse_mapping_check)
+{
+        static const char *remote = "";
+        if (utmp_len > 0)
+                remote = get_canonical_hostname(reverse_mapping_check);
+        if (utmp_len == 0 || strlen(remote) > utmp_len)
+                remote = get_remote_ipaddr();
+        return remote;
+}
+
+/* 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);
+}