1 /* $OpenBSD: canohost.c,v 1.77 2023/03/31 04:42:29 dtucker 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 if (sock < 0)
76 return NULL;
77
78 /* Get IP address of client. */
79 addrlen = sizeof(addr);
80 memset(&addr, 0, sizeof(addr));
81
82 if (remote) {
83 if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) != 0)
84 return NULL;
85 } else {
86 if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) != 0)
87 return NULL;
88 }
89
90 /* Work around Linux IPv6 weirdness */
91 if (addr.ss_family == AF_INET6) {
92 addrlen = sizeof(struct sockaddr_in6);
93 ipv64_normalise_mapped(&addr, &addrlen);
94 }
95
96 switch (addr.ss_family) {
97 case AF_INET:
98 case AF_INET6:
99 /* Get the address in ascii. */
100 if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
101 sizeof(ntop), NULL, 0, flags)) != 0) {
102 error_f("getnameinfo %d failed: %s",
103 flags, ssh_gai_strerror(r));
104 return NULL;
105 }
106 return xstrdup(ntop);
107 case AF_UNIX:
108 /* Get the Unix domain socket path. */
109 return xstrdup(((struct sockaddr_un *)&addr)->sun_path);
110 default:
111 /* We can't look up remote Unix domain sockets. */
112 return NULL;
113 }
114 }
115
116 char *
get_peer_ipaddr(int sock)117 get_peer_ipaddr(int sock)
118 {
119 char *p;
120
121 if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
122 return p;
123 return xstrdup("UNKNOWN");
124 }
125
126 char *
get_local_ipaddr(int sock)127 get_local_ipaddr(int sock)
128 {
129 char *p;
130
131 if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
132 return p;
133 return xstrdup("UNKNOWN");
134 }
135
136 char *
get_local_name(int fd)137 get_local_name(int fd)
138 {
139 char *host, myname[NI_MAXHOST];
140
141 /* Assume we were passed a socket */
142 if ((host = get_socket_address(fd, 0, NI_NAMEREQD)) != NULL)
143 return host;
144
145 /* Handle the case where we were passed a pipe */
146 if (gethostname(myname, sizeof(myname)) == -1) {
147 verbose_f("gethostname: %s", strerror(errno));
148 host = xstrdup("UNKNOWN");
149 } else {
150 host = xstrdup(myname);
151 }
152
153 return host;
154 }
155
156 /* Returns the local/remote port for the socket. */
157
158 static int
get_sock_port(int sock,int local)159 get_sock_port(int sock, int local)
160 {
161 struct sockaddr_storage from;
162 socklen_t fromlen;
163 char strport[NI_MAXSERV];
164 int r;
165
166 if (sock < 0)
167 return -1;
168 /* Get IP address of client. */
169 fromlen = sizeof(from);
170 memset(&from, 0, sizeof(from));
171 if (local) {
172 if (getsockname(sock, (struct sockaddr *)&from, &fromlen) == -1) {
173 error("getsockname failed: %.100s", strerror(errno));
174 return 0;
175 }
176 } else {
177 if (getpeername(sock, (struct sockaddr *)&from, &fromlen) == -1) {
178 debug("getpeername failed: %.100s", strerror(errno));
179 return -1;
180 }
181 }
182
183 /* Work around Linux IPv6 weirdness */
184 if (from.ss_family == AF_INET6)
185 fromlen = sizeof(struct sockaddr_in6);
186
187 /* Non-inet sockets don't have a port number. */
188 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
189 return 0;
190
191 /* Return port number. */
192 if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
193 strport, sizeof(strport), NI_NUMERICSERV)) != 0)
194 fatal_f("getnameinfo NI_NUMERICSERV failed: %s",
195 ssh_gai_strerror(r));
196 return atoi(strport);
197 }
198
199 int
get_peer_port(int sock)200 get_peer_port(int sock)
201 {
202 return get_sock_port(sock, 0);
203 }
204
205 int
get_local_port(int sock)206 get_local_port(int sock)
207 {
208 return get_sock_port(sock, 1);
209 }
210