1 /* $OpenBSD: canohost.c,v 1.74 2019/06/28 13:35:04 deraadt Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * Functions for returning the canonical host name of the remote site.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 */
14
15 #include "includes.h"
16
17 #include <sys/types.h>
18 #include <sys/socket.h>
19 #include <sys/un.h>
20
21 #include <netinet/in.h>
22 #include <arpa/inet.h>
23
24 #include <errno.h>
25 #include <netdb.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <stdarg.h>
30 #include <unistd.h>
31
32 #include "xmalloc.h"
33 #include "packet.h"
34 #include "log.h"
35 #include "canohost.h"
36 #include "misc.h"
37
38 void
ipv64_normalise_mapped(struct sockaddr_storage * addr,socklen_t * len)39 ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
40 {
41 struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;
42 struct sockaddr_in *a4 = (struct sockaddr_in *)addr;
43 struct in_addr inaddr;
44 u_int16_t port;
45
46 if (addr->ss_family != AF_INET6 ||
47 !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
48 return;
49
50 debug3("Normalising mapped IPv4 in IPv6 address");
51
52 memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
53 port = a6->sin6_port;
54
55 memset(a4, 0, sizeof(*a4));
56
57 a4->sin_family = AF_INET;
58 *len = sizeof(*a4);
59 memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));
60 a4->sin_port = port;
61 }
62
63 /*
64 * Returns the local/remote IP-address/hostname of socket as a string.
65 * The returned string must be freed.
66 */
67 static char *
get_socket_address(int sock,int remote,int flags)68 get_socket_address(int sock, int remote, int flags)
69 {
70 struct sockaddr_storage addr;
71 socklen_t addrlen;
72 char ntop[NI_MAXHOST];
73 int r;
74
75 /* Get IP address of client. */
76 addrlen = sizeof(addr);
77 memset(&addr, 0, sizeof(addr));
78
79 if (remote) {
80 if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) != 0)
81 return NULL;
82 } else {
83 if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) != 0)
84 return NULL;
85 }
86
87 /* Work around Linux IPv6 weirdness */
88 if (addr.ss_family == AF_INET6) {
89 addrlen = sizeof(struct sockaddr_in6);
90 ipv64_normalise_mapped(&addr, &addrlen);
91 }
92
93 switch (addr.ss_family) {
94 case AF_INET:
95 case AF_INET6:
96 /* Get the address in ascii. */
97 if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
98 sizeof(ntop), NULL, 0, flags)) != 0) {
99 error("%s: getnameinfo %d failed: %s", __func__,
100 flags, ssh_gai_strerror(r));
101 return NULL;
102 }
103 return xstrdup(ntop);
104 case AF_UNIX:
105 /* Get the Unix domain socket path. */
106 return xstrdup(((struct sockaddr_un *)&addr)->sun_path);
107 default:
108 /* We can't look up remote Unix domain sockets. */
109 return NULL;
110 }
111 }
112
113 char *
get_peer_ipaddr(int sock)114 get_peer_ipaddr(int sock)
115 {
116 char *p;
117
118 if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
119 return p;
120 return xstrdup("UNKNOWN");
121 }
122
123 char *
get_local_ipaddr(int sock)124 get_local_ipaddr(int sock)
125 {
126 char *p;
127
128 if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
129 return p;
130 return xstrdup("UNKNOWN");
131 }
132
133 char *
get_local_name(int fd)134 get_local_name(int fd)
135 {
136 char *host, myname[NI_MAXHOST];
137
138 /* Assume we were passed a socket */
139 if ((host = get_socket_address(fd, 0, NI_NAMEREQD)) != NULL)
140 return host;
141
142 /* Handle the case where we were passed a pipe */
143 if (gethostname(myname, sizeof(myname)) == -1) {
144 verbose("%s: gethostname: %s", __func__, strerror(errno));
145 host = xstrdup("UNKNOWN");
146 } else {
147 host = xstrdup(myname);
148 }
149
150 return host;
151 }
152
153 /* Returns the local/remote port for the socket. */
154
155 static int
get_sock_port(int sock,int local)156 get_sock_port(int sock, int local)
157 {
158 struct sockaddr_storage from;
159 socklen_t fromlen;
160 char strport[NI_MAXSERV];
161 int r;
162
163 /* Get IP address of client. */
164 fromlen = sizeof(from);
165 memset(&from, 0, sizeof(from));
166 if (local) {
167 if (getsockname(sock, (struct sockaddr *)&from, &fromlen) == -1) {
168 error("getsockname failed: %.100s", strerror(errno));
169 return 0;
170 }
171 } else {
172 if (getpeername(sock, (struct sockaddr *)&from, &fromlen) == -1) {
173 debug("getpeername failed: %.100s", strerror(errno));
174 return -1;
175 }
176 }
177
178 /* Work around Linux IPv6 weirdness */
179 if (from.ss_family == AF_INET6)
180 fromlen = sizeof(struct sockaddr_in6);
181
182 /* Non-inet sockets don't have a port number. */
183 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
184 return 0;
185
186 /* Return port number. */
187 if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
188 strport, sizeof(strport), NI_NUMERICSERV)) != 0)
189 fatal("%s: getnameinfo NI_NUMERICSERV failed: %s", __func__,
190 ssh_gai_strerror(r));
191 return atoi(strport);
192 }
193
194 int
get_peer_port(int sock)195 get_peer_port(int sock)
196 {
197 return get_sock_port(sock, 0);
198 }
199
200 int
get_local_port(int sock)201 get_local_port(int sock)
202 {
203 return get_sock_port(sock, 1);
204 }
205