lib/libtls/tls_client.c

   1 /* $OpenBSD: tls_client.c,v 1.43 2017/08/10 18:18:30 jsing Exp $ */
   2 /*
   3  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20
  21 #include <arpa/inet.h>
  22 #include <netinet/in.h>
  23
  24 #include <netdb.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27
  28 #include <openssl/err.h>
  29 #include <openssl/x509.h>
  30
  31 #include <tls.h>
  32 #include "tls_internal.h"
  33
  34 struct tls *
  35 tls_client(void)
  36 {
  37         struct tls *ctx;
  38
  39         if ((ctx = tls_new()) == NULL)
  40                 return (NULL);
  41
  42         ctx->flags |= TLS_CLIENT;
  43
  44         return (ctx);
  45 }
  46
  47 int
  48 tls_connect(struct tls *ctx, const char *host, const char *port)
  49 {
  50         return tls_connect_servername(ctx, host, port, NULL);
  51 }
  52
  53 int
  54 tls_connect_servername(struct tls *ctx, const char *host, const char *port,
  55     const char *servername)
  56 {
  57         struct addrinfo hints, *res, *res0;
  58         const char *h = NULL, *p = NULL;
  59         char *hs = NULL, *ps = NULL;
  60         int rv = -1, s = -1, ret;
  61
  62         if ((ctx->flags & TLS_CLIENT) == 0) {
  63                 tls_set_errorx(ctx, "not a client context");
  64                 goto err;
  65         }
  66
  67         if (host == NULL) {
  68                 tls_set_errorx(ctx, "host not specified");
  69                 goto err;
  70         }
  71
  72         /*
  73          * If port is NULL try to extract a port from the specified host,
  74          * otherwise use the default.
  75          */
  76         if ((p = (char *)port) == NULL) {
  77                 ret = tls_host_port(host, &hs, &ps);
  78                 if (ret == -1) {
  79                         tls_set_errorx(ctx, "memory allocation failure");
  80                         goto err;
  81                 }
  82                 if (ret != 0) {
  83                         tls_set_errorx(ctx, "no port provided");
  84                         goto err;
  85                 }
  86         }
  87
  88         h = (hs != NULL) ? hs : host;
  89         p = (ps != NULL) ? ps : port;
  90
  91         /*
  92          * First check if the host is specified as a numeric IP address,
  93          * either IPv4 or IPv6, before trying to resolve the host.
  94          * The AI_ADDRCONFIG resolver option will not return IPv4 or IPv6
  95          * records if it is not configured on an interface;  not considering
  96          * loopback addresses.  Checking the numeric addresses first makes
  97          * sure that connection attempts to numeric addresses and especially
  98          * 127.0.0.1 or ::1 loopback addresses are always possible.
  99          */
 100         memset(&hints, 0, sizeof(hints));
 101         hints.ai_socktype = SOCK_STREAM;
 102
 103         /* try as an IPv4 literal */
 104         hints.ai_family = AF_INET;
 105         hints.ai_flags = AI_NUMERICHOST;
 106         if (getaddrinfo(h, p, &hints, &res0) != 0) {
 107                 /* try again as an IPv6 literal */
 108                 hints.ai_family = AF_INET6;
 109                 if (getaddrinfo(h, p, &hints, &res0) != 0) {
 110                         /* last try, with name resolution and save the error */
 111                         hints.ai_family = AF_UNSPEC;
 112                         hints.ai_flags = AI_ADDRCONFIG;
 113                         if ((s = getaddrinfo(h, p, &hints, &res0)) != 0) {
 114                                 tls_set_error(ctx, "%s", gai_strerror(s));
 115                                 goto err;
 116                         }
 117                 }
 118         }
 119
 120         /* It was resolved somehow; now try connecting to what we got */
 121         s = -1;
 122         for (res = res0; res; res = res->ai_next) {
 123                 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 124                 if (s == -1) {
 125                         tls_set_error(ctx, "socket");
 126                         continue;
 127                 }
 128                 if (connect(s, res->ai_addr, res->ai_addrlen) == -1) {
 129                         tls_set_error(ctx, "connect");
 130                         close(s);
 131                         s = -1;
 132                         continue;
 133                 }
 134
 135                 break;  /* Connected. */
 136         }
 137         freeaddrinfo(res0);
 138
 139         if (s == -1)
 140                 goto err;
 141
 142         if (servername == NULL)
 143                 servername = h;
 144
 145         if (tls_connect_socket(ctx, s, servername) != 0) {
 146                 close(s);
 147                 goto err;
 148         }
 149
 150         ctx->socket = s;
 151
 152         rv = 0;
 153
 154  err:
 155         free(hs);
 156         free(ps);
 157
 158         return (rv);
 159 }
 160
 161 static int
 162 tls_connect_common(struct tls *ctx, const char *servername)
 163 {
 164         union tls_addr addrbuf;
 165         int rv = -1;
 166
 167         if ((ctx->flags & TLS_CLIENT) == 0) {
 168                 tls_set_errorx(ctx, "not a client context");
 169                 goto err;
 170         }
 171
 172         if (servername != NULL) {
 173                 if ((ctx->servername = strdup(servername)) == NULL) {
 174                         tls_set_errorx(ctx, "out of memory");
 175                         goto err;
 176                 }
 177         }
 178
 179         if ((ctx->ssl_ctx = SSL_CTX_new(SSLv23_client_method())) == NULL) {
 180                 tls_set_errorx(ctx, "ssl context failure");
 181                 goto err;
 182         }
 183
 184         if (tls_configure_ssl(ctx, ctx->ssl_ctx) != 0)
 185                 goto err;
 186
 187         if (tls_configure_ssl_keypair(ctx, ctx->ssl_ctx,
 188             ctx->config->keypair, 0) != 0)
 189                 goto err;
 190
 191         if (ctx->config->verify_name) {
 192                 if (servername == NULL) {
 193                         tls_set_errorx(ctx, "server name not specified");
 194                         goto err;
 195                 }
 196         }
 197
 198         if (tls_configure_ssl_verify(ctx, ctx->ssl_ctx, SSL_VERIFY_PEER) == -1)
 199                 goto err;
 200
 201         if (ctx->config->ecdhecurves != NULL) {
 202                 if (SSL_CTX_set1_groups(ctx->ssl_ctx, ctx->config->ecdhecurves,
 203                     ctx->config->ecdhecurves_len) != 1) {
 204                         tls_set_errorx(ctx, "failed to set ecdhe curves");
 205                         goto err;
 206                 }
 207         }
 208
 209         if (SSL_CTX_set_tlsext_status_cb(ctx->ssl_ctx, tls_ocsp_verify_cb) != 1) {
 210                 tls_set_errorx(ctx, "ssl OCSP verification setup failure");
 211                 goto err;
 212         }
 213
 214         if ((ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) {
 215                 tls_set_errorx(ctx, "ssl connection failure");
 216                 goto err;
 217         }
 218
 219         if (SSL_set_app_data(ctx->ssl_conn, ctx) != 1) {
 220                 tls_set_errorx(ctx, "ssl application data failure");
 221                 goto err;
 222         }
 223
 224         if (SSL_set_tlsext_status_type(ctx->ssl_conn, TLSEXT_STATUSTYPE_ocsp) != 1) {
 225                 tls_set_errorx(ctx, "ssl OCSP extension setup failure");
 226                 goto err;
 227         }
 228
 229         /*
 230          * RFC4366 (SNI): Literal IPv4 and IPv6 addresses are not
 231          * permitted in "HostName".
 232          */
 233         if (servername != NULL &&
 234             inet_pton(AF_INET, servername, &addrbuf) != 1 &&
 235             inet_pton(AF_INET6, servername, &addrbuf) != 1) {
 236                 if (SSL_set_tlsext_host_name(ctx->ssl_conn, servername) == 0) {
 237                         tls_set_errorx(ctx, "server name indication failure");
 238                         goto err;
 239                 }
 240         }
 241
 242         ctx->state |= TLS_CONNECTED;
 243         rv = 0;
 244
 245  err:
 246         return (rv);
 247 }
 248
 249 int
 250 tls_connect_socket(struct tls *ctx, int s, const char *servername)
 251 {
 252         return tls_connect_fds(ctx, s, s, servername);
 253 }
 254
 255 int
 256 tls_connect_fds(struct tls *ctx, int fd_read, int fd_write,
 257     const char *servername)
 258 {
 259         int rv = -1;
 260
 261         if (fd_read < 0 || fd_write < 0) {
 262                 tls_set_errorx(ctx, "invalid file descriptors");
 263                 goto err;
 264         }
 265
 266         if (tls_connect_common(ctx, servername) != 0)
 267                 goto err;
 268
 269         if (SSL_set_rfd(ctx->ssl_conn, fd_read) != 1 ||
 270             SSL_set_wfd(ctx->ssl_conn, fd_write) != 1) {
 271                 tls_set_errorx(ctx, "ssl file descriptor failure");
 272                 goto err;
 273         }
 274
 275         rv = 0;
 276  err:
 277         return (rv);
 278 }
 279
 280 int
 281 tls_connect_cbs(struct tls *ctx, tls_read_cb read_cb,
 282     tls_write_cb write_cb, void *cb_arg, const char *servername)
 283 {
 284         int rv = -1;
 285
 286         if (tls_connect_common(ctx, servername) != 0)
 287                 goto err;
 288
 289         if (tls_set_cbs(ctx, read_cb, write_cb, cb_arg) != 0)
 290                 goto err;
 291
 292         rv = 0;
 293
 294  err:
 295         return (rv);
 296 }
 297
 298 int
 299 tls_handshake_client(struct tls *ctx)
 300 {
 301         X509 *cert = NULL;
 302         int match, ssl_ret;
 303         int rv = -1;
 304
 305         if ((ctx->flags & TLS_CLIENT) == 0) {
 306                 tls_set_errorx(ctx, "not a client context");
 307                 goto err;
 308         }
 309
 310         if ((ctx->state & TLS_CONNECTED) == 0) {
 311                 tls_set_errorx(ctx, "context not connected");
 312                 goto err;
 313         }
 314
 315         ctx->state |= TLS_SSL_NEEDS_SHUTDOWN;
 316
 317         ERR_clear_error();
 318         if ((ssl_ret = SSL_connect(ctx->ssl_conn)) != 1) {
 319                 rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "handshake");
 320                 goto err;
 321         }
 322
 323         if (ctx->config->verify_name) {
 324                 cert = SSL_get_peer_certificate(ctx->ssl_conn);
 325                 if (cert == NULL) {
 326                         tls_set_errorx(ctx, "no server certificate");
 327                         goto err;
 328                 }
 329                 if (tls_check_name(ctx, cert, ctx->servername, &match) == -1)
 330                         goto err;
 331                 if (!match) {
 332                         tls_set_errorx(ctx, "name `%s' not present in"
 333                             " server certificate", ctx->servername);
 334                         goto err;
 335                 }
 336         }
 337
 338         ctx->state |= TLS_HANDSHAKE_COMPLETE;
 339         rv = 0;
 340
 341  err:
 342         X509_free(cert);
 343
 344         return (rv);
 345 }