1 /* $NetBSD: qmqpd_peer.c,v 1.2 2017/02/14 01:16:47 christos Exp $ */ 2 3 /*++ 4 /* NAME 5 /* qmqpd_peer 3 6 /* SUMMARY 7 /* look up peer name/address information 8 /* SYNOPSIS 9 /* #include "qmqpd.h" 10 /* 11 /* void qmqpd_peer_init(state) 12 /* QMQPD_STATE *state; 13 /* 14 /* void qmqpd_peer_reset(state) 15 /* QMQPD_STATE *state; 16 /* DESCRIPTION 17 /* The qmqpd_peer_init() routine attempts to produce a printable 18 /* version of the peer name and address of the specified socket. 19 /* Where information is unavailable, the name and/or address 20 /* are set to "unknown". 21 /* 22 /* qmqpd_peer_init() updates the following fields: 23 /* .IP name 24 /* The client hostname. An unknown name is represented by the 25 /* string "unknown". 26 /* .IP addr 27 /* Printable representation of the client address. 28 /* .IP namaddr 29 /* String of the form: "name[addr]:port". 30 /* .PP 31 /* qmqpd_peer_reset() releases memory allocated by qmqpd_peer_init(). 32 /* LICENSE 33 /* .ad 34 /* .fi 35 /* The Secure Mailer license must be distributed with this software. 36 /* AUTHOR(S) 37 /* Wietse Venema 38 /* IBM T.J. Watson Research 39 /* P.O. Box 704 40 /* Yorktown Heights, NY 10598, USA 41 /*--*/ 42 43 /* System library. */ 44 45 #include <sys_defs.h> 46 #include <sys/socket.h> 47 #include <netinet/in.h> 48 #include <arpa/inet.h> 49 #include <stdio.h> /* strerror() */ 50 #include <errno.h> 51 #include <netdb.h> 52 #include <string.h> 53 54 /* Utility library. */ 55 56 #include <msg.h> 57 #include <mymalloc.h> 58 #include <stringops.h> 59 #include <myaddrinfo.h> 60 #include <sock_addr.h> 61 #include <inet_proto.h> 62 #include <split_at.h> 63 64 /* Global library. */ 65 66 #include <mail_proto.h> 67 #include <valid_mailhost_addr.h> 68 #include <mail_params.h> 69 70 /* Application-specific. */ 71 72 #include "qmqpd.h" 73 74 /* qmqpd_peer_init - initialize peer information */ 75 76 void qmqpd_peer_init(QMQPD_STATE *state) 77 { 78 const char *myname = "qmqpd_peer_init"; 79 struct sockaddr_storage ss; 80 struct sockaddr *sa; 81 SOCKADDR_SIZE sa_length; 82 INET_PROTO_INFO *proto_info = inet_proto_info(); 83 84 sa = (struct sockaddr *) &ss; 85 sa_length = sizeof(ss); 86 87 /* 88 * Look up the peer address information. 89 */ 90 if (getpeername(vstream_fileno(state->client), sa, &sa_length) >= 0) { 91 errno = 0; 92 } 93 94 /* 95 * If peer went away, give up. 96 */ 97 if (errno != 0 && errno != ENOTSOCK) { 98 state->name = mystrdup(CLIENT_NAME_UNKNOWN); 99 state->addr = mystrdup(CLIENT_ADDR_UNKNOWN); 100 state->rfc_addr = mystrdup(CLIENT_ADDR_UNKNOWN); 101 state->addr_family = AF_UNSPEC; 102 state->port = mystrdup(CLIENT_PORT_UNKNOWN); 103 } 104 105 /* 106 * Convert the client address to printable address and hostname. 107 * 108 * XXX If we're given an IPv6 (or IPv4) connection from, e.g., inetd, while 109 * Postfix IPv6 (or IPv4) support is turned off, don't (skip to the final 110 * else clause, pretend the origin is localhost[127.0.0.1], and become an 111 * open relay). 112 */ 113 else if (errno == 0 114 && (sa->sa_family == AF_INET 115 #ifdef AF_INET6 116 || sa->sa_family == AF_INET6 117 #endif 118 )) { 119 MAI_HOSTNAME_STR client_name; 120 MAI_HOSTADDR_STR client_addr; 121 MAI_SERVPORT_STR client_port; 122 int aierr; 123 char *colonp; 124 125 /* 126 * Sanity check: we can't use sockets that we're not configured for. 127 */ 128 if (strchr((char *) proto_info->sa_family_list, sa->sa_family) == 0) 129 msg_fatal("cannot handle socket type %s with \"%s = %s\"", 130 #ifdef AF_INET6 131 sa->sa_family == AF_INET6 ? "AF_INET6" : 132 #endif 133 sa->sa_family == AF_INET ? "AF_INET" : 134 "other", VAR_INET_PROTOCOLS, var_inet_protocols); 135 136 /* 137 * Sorry, but there are some things that we just cannot do while 138 * connected to the network. 139 */ 140 if (geteuid() != var_owner_uid || getuid() != var_owner_uid) { 141 msg_error("incorrect QMQP server privileges: uid=%lu euid=%lu", 142 (unsigned long) getuid(), (unsigned long) geteuid()); 143 msg_fatal("the Postfix QMQP server must run with $%s privileges", 144 VAR_MAIL_OWNER); 145 } 146 147 /* 148 * Convert the client address to printable form. 149 */ 150 if ((aierr = sockaddr_to_hostaddr(sa, sa_length, &client_addr, 151 &client_port, 0)) != 0) 152 msg_fatal("%s: cannot convert client address/port to string: %s", 153 myname, MAI_STRERROR(aierr)); 154 state->port = mystrdup(client_port.buf); 155 156 /* 157 * XXX Require that the infrastructure strips off the IPv6 datalink 158 * suffix to avoid false alarms with strict address syntax checks. 159 */ 160 #ifdef HAS_IPV6 161 if (strchr(client_addr.buf, '%') != 0) 162 msg_panic("%s: address %s has datalink suffix", 163 myname, client_addr.buf); 164 #endif 165 166 /* 167 * We convert IPv4-in-IPv6 address to 'true' IPv4 address early on, 168 * but only if IPv4 support is enabled (why would anyone want to turn 169 * it off)? With IPv4 support enabled we have no need for the IPv6 170 * form in logging, hostname verification and access checks. 171 */ 172 #ifdef HAS_IPV6 173 if (sa->sa_family == AF_INET6) { 174 if (strchr((char *) proto_info->sa_family_list, AF_INET) != 0 175 && IN6_IS_ADDR_V4MAPPED(&SOCK_ADDR_IN6_ADDR(sa)) 176 && (colonp = strrchr(client_addr.buf, ':')) != 0) { 177 struct addrinfo *res0; 178 179 if (msg_verbose > 1) 180 msg_info("%s: rewriting V4-mapped address \"%s\" to \"%s\"", 181 myname, client_addr.buf, colonp + 1); 182 183 state->addr = mystrdup(colonp + 1); 184 state->rfc_addr = mystrdup(colonp + 1); 185 state->addr_family = AF_INET; 186 aierr = hostaddr_to_sockaddr(state->addr, (char *) 0, 0, &res0); 187 if (aierr) 188 msg_fatal("%s: cannot convert %s from string to binary: %s", 189 myname, state->addr, MAI_STRERROR(aierr)); 190 sa_length = res0->ai_addrlen; 191 if (sa_length > sizeof(ss)) 192 sa_length = sizeof(ss); 193 memcpy((void *) sa, res0->ai_addr, sa_length); 194 freeaddrinfo(res0); 195 } 196 197 /* 198 * Following RFC 2821 section 4.1.3, an IPv6 address literal gets 199 * a prefix of 'IPv6:'. We do this consistently for all IPv6 200 * addresses that that appear in headers or envelopes. The fact 201 * that valid_mailhost_addr() enforces the form helps of course. 202 * We use the form without IPV6: prefix when doing access 203 * control, or when accessing the connection cache. 204 */ 205 else { 206 state->addr = mystrdup(client_addr.buf); 207 state->rfc_addr = 208 concatenate(IPV6_COL, client_addr.buf, (char *) 0); 209 state->addr_family = sa->sa_family; 210 } 211 } 212 213 /* 214 * An IPv4 address is in dotted quad decimal form. 215 */ 216 else 217 #endif 218 { 219 state->addr = mystrdup(client_addr.buf); 220 state->rfc_addr = mystrdup(client_addr.buf); 221 state->addr_family = sa->sa_family; 222 } 223 224 /* 225 * Look up and sanity check the client hostname. 226 * 227 * It is unsafe to allow numeric hostnames, especially because there 228 * exists pressure to turn off the name->addr double check. In that 229 * case an attacker could trivally bypass access restrictions. 230 * 231 * sockaddr_to_hostname() already rejects malformed or numeric names. 232 */ 233 #define REJECT_PEER_NAME(state) { \ 234 myfree(state->name); \ 235 state->name = mystrdup(CLIENT_NAME_UNKNOWN); \ 236 } 237 238 if ((aierr = sockaddr_to_hostname(sa, sa_length, &client_name, 239 (MAI_SERVNAME_STR *) 0, 0)) != 0) { 240 state->name = mystrdup(CLIENT_NAME_UNKNOWN); 241 } else { 242 struct addrinfo *res0; 243 struct addrinfo *res; 244 245 state->name = mystrdup(client_name.buf); 246 247 /* 248 * Reject the hostname if it does not list the peer address. 249 */ 250 aierr = hostname_to_sockaddr_pf(state->name, state->addr_family, 251 (char *) 0, 0, &res0); 252 if (aierr) { 253 msg_warn("hostname %s does not resolve to address %s: %s", 254 state->name, state->addr, MAI_STRERROR(aierr)); 255 REJECT_PEER_NAME(state); 256 } else { 257 for (res = res0; /* void */ ; res = res->ai_next) { 258 if (res == 0) { 259 msg_warn("hostname %s does not resolve to address %s", 260 state->addr, state->name); 261 REJECT_PEER_NAME(state); 262 break; 263 } 264 if (strchr((char *) proto_info->sa_family_list, res->ai_family) == 0) { 265 msg_info("skipping address family %d for host %s", 266 res->ai_family, state->name); 267 continue; 268 } 269 if (sock_addr_cmp_addr(res->ai_addr, sa) == 0) 270 break; /* keep peer name */ 271 } 272 freeaddrinfo(res0); 273 } 274 } 275 } 276 277 /* 278 * If it's not Internet, assume the client is local, and avoid using the 279 * naming service because that can hang when the machine is disconnected. 280 */ 281 else { 282 state->name = mystrdup("localhost"); 283 state->addr = mystrdup("127.0.0.1"); /* XXX bogus. */ 284 state->rfc_addr = mystrdup("127.0.0.1");/* XXX bogus. */ 285 state->addr_family = AF_UNSPEC; 286 state->port = mystrdup("0"); /* XXX bogus. */ 287 } 288 289 /* 290 * Do the name[addr]:port formatting for pretty reports. 291 */ 292 state->namaddr = 293 concatenate(state->name, "[", state->addr, "]", 294 var_qmqpd_client_port_log ? ":" : (char *) 0, 295 state->port, (char *) 0); 296 } 297 298 /* qmqpd_peer_reset - destroy peer information */ 299 300 void qmqpd_peer_reset(QMQPD_STATE *state) 301 { 302 myfree(state->name); 303 myfree(state->addr); 304 myfree(state->namaddr); 305 myfree(state->rfc_addr); 306 myfree(state->port); 307 } 308