IABSD.fr/src/lib/libtls/tls_client.c

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• Author : tb
  Date : 2021-10-21 08:38:11
  Hash : 1b7b92c5
  Message : Eliminate a dead assignment and a weird cast. Adjust a comment to reality while there. ok jsing

• lib/libtls/tls_client.c

• /* $OpenBSD: tls_client.c,v 1.48 2021/10/21 08:38:11 tb Exp $ */
  /*
   * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/stat.h>
  
  #include <arpa/inet.h>
  #include <netinet/in.h>
  
  #include <limits.h>
  #include <netdb.h>
  #include <stdlib.h>
  #include <unistd.h>
  
  #include <openssl/err.h>
  #include <openssl/x509.h>
  
  #include <tls.h>
  #include "tls_internal.h"
  
  struct tls *
  tls_client(void)
  {
  	struct tls *ctx;
  
  	if (tls_init() == -1)
  		return (NULL);
  
  	if ((ctx = tls_new()) == NULL)
  		return (NULL);
  
  	ctx->flags |= TLS_CLIENT;
  
  	return (ctx);
  }
  
  int
  tls_connect(struct tls *ctx, const char *host, const char *port)
  {
  	return tls_connect_servername(ctx, host, port, NULL);
  }
  
  int
  tls_connect_servername(struct tls *ctx, const char *host, const char *port,
      const char *servername)
  {
  	struct addrinfo hints, *res, *res0;
  	const char *h = NULL, *p = NULL;
  	char *hs = NULL, *ps = NULL;
  	int rv = -1, s = -1, ret;
  
  	if ((ctx->flags & TLS_CLIENT) == 0) {
  		tls_set_errorx(ctx, "not a client context");
  		goto err;
  	}
  
  	if (host == NULL) {
  		tls_set_errorx(ctx, "host not specified");
  		goto err;
  	}
  
  	/* If port is NULL, try to extract a port from the specified host. */
  	if (port == NULL) {
  		ret = tls_host_port(host, &hs, &ps);
  		if (ret == -1) {
  			tls_set_errorx(ctx, "memory allocation failure");
  			goto err;
  		}
  		if (ret != 0) {
  			tls_set_errorx(ctx, "no port provided");
  			goto err;
  		}
  	}
  
  	h = (hs != NULL) ? hs : host;
  	p = (ps != NULL) ? ps : port;
  
  	/*
  	 * First check if the host is specified as a numeric IP address,
  	 * either IPv4 or IPv6, before trying to resolve the host.
  	 * The AI_ADDRCONFIG resolver option will not return IPv4 or IPv6
  	 * records if it is not configured on an interface;  not considering
  	 * loopback addresses.  Checking the numeric addresses first makes
  	 * sure that connection attempts to numeric addresses and especially
  	 * 127.0.0.1 or ::1 loopback addresses are always possible.
  	 */
  	memset(&hints, 0, sizeof(hints));
  	hints.ai_socktype = SOCK_STREAM;
  
  	/* try as an IPv4 literal */
  	hints.ai_family = AF_INET;
  	hints.ai_flags = AI_NUMERICHOST;
  	if (getaddrinfo(h, p, &hints, &res0) != 0) {
  		/* try again as an IPv6 literal */
  		hints.ai_family = AF_INET6;
  		if (getaddrinfo(h, p, &hints, &res0) != 0) {
  			/* last try, with name resolution and save the error */
  			hints.ai_family = AF_UNSPEC;
  			hints.ai_flags = AI_ADDRCONFIG;
  			if ((s = getaddrinfo(h, p, &hints, &res0)) != 0) {
  				tls_set_error(ctx, "%s", gai_strerror(s));
  				goto err;
  			}
  		}
  	}
  
  	/* It was resolved somehow; now try connecting to what we got */
  	s = -1;
  	for (res = res0; res; res = res->ai_next) {
  		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
  		if (s == -1) {
  			tls_set_error(ctx, "socket");
  			continue;
  		}
  		if (connect(s, res->ai_addr, res->ai_addrlen) == -1) {
  			tls_set_error(ctx, "connect");
  			close(s);
  			s = -1;
  			continue;
  		}
  
  		break;  /* Connected. */
  	}
  	freeaddrinfo(res0);
  
  	if (s == -1)
  		goto err;
  
  	if (servername == NULL)
  		servername = h;
  
  	if (tls_connect_socket(ctx, s, servername) != 0) {
  		close(s);
  		goto err;
  	}
  
  	ctx->socket = s;
  
  	rv = 0;
  
   err:
  	free(hs);
  	free(ps);
  
  	return (rv);
  }
  
  static int
  tls_client_read_session(struct tls *ctx)
  {
  	int sfd = ctx->config->session_fd;
  	uint8_t *session = NULL;
  	size_t session_len = 0;
  	SSL_SESSION *ss = NULL;
  	BIO *bio = NULL;
  	struct stat sb;
  	ssize_t n;
  	int rv = -1;
  
  	if (fstat(sfd, &sb) == -1) {
  		tls_set_error(ctx, "failed to stat session file");
  		goto err;
  	}
  	if (sb.st_size < 0 || sb.st_size > INT_MAX) {
  		tls_set_errorx(ctx, "invalid session file size");
  		goto err;
  	}
  	session_len = (size_t)sb.st_size;
  
  	/* A zero size file means that we do not yet have a valid session. */
  	if (session_len == 0)
  		goto done;
  
  	if ((session = malloc(session_len)) == NULL)
  		goto err;
  
  	n = pread(sfd, session, session_len, 0);
  	if (n < 0 || (size_t)n != session_len) {
  		tls_set_error(ctx, "failed to read session file");
  		goto err;
  	}
  	if ((bio = BIO_new_mem_buf(session, session_len)) == NULL)
  		goto err;
  	if ((ss = PEM_read_bio_SSL_SESSION(bio, NULL, tls_password_cb,
  	    NULL)) == NULL) {
  		tls_set_errorx(ctx, "failed to parse session");
  		goto err;
  	}
  
  	if (SSL_set_session(ctx->ssl_conn, ss) != 1) {
  		tls_set_errorx(ctx, "failed to set session");
  		goto err;
  	}
  
   done:
  	rv = 0;
  
   err:
  	freezero(session, session_len);
  	SSL_SESSION_free(ss);
  	BIO_free(bio);
  
  	return rv;
  }
  
  static int
  tls_client_write_session(struct tls *ctx)
  {
  	int sfd = ctx->config->session_fd;
  	SSL_SESSION *ss = NULL;
  	BIO *bio = NULL;
  	long data_len;
  	char *data;
  	off_t offset;
  	size_t len;
  	ssize_t n;
  	int rv = -1;
  
  	if ((ss = SSL_get1_session(ctx->ssl_conn)) == NULL) {
  		if (ftruncate(sfd, 0) == -1) {
  			tls_set_error(ctx, "failed to truncate session file");
  			goto err;
  		}
  		goto done;
  	}
  
  	if ((bio = BIO_new(BIO_s_mem())) == NULL)
  		goto err;
  	if (PEM_write_bio_SSL_SESSION(bio, ss) == 0)
  		goto err;
  	if ((data_len = BIO_get_mem_data(bio, &data)) <= 0)
  		goto err;
  
  	len = (size_t)data_len;
  	offset = 0;
  
  	if (ftruncate(sfd, len) == -1) {
  		tls_set_error(ctx, "failed to truncate session file");
  		goto err;
  	}
  	while (len > 0) {
  		if ((n = pwrite(sfd, data + offset, len, offset)) == -1) {
  			tls_set_error(ctx, "failed to write session file");
  			goto err;
  		}
  		offset += n;
  		len -= n;
  	}
  
   done:
  	rv = 0;
  
   err:
  	SSL_SESSION_free(ss);
  	BIO_free_all(bio);
  
  	return (rv);
  }
  
  static int
  tls_connect_common(struct tls *ctx, const char *servername)
  {
  	union tls_addr addrbuf;
  	size_t servername_len;
  	int rv = -1;
  
  	if ((ctx->flags & TLS_CLIENT) == 0) {
  		tls_set_errorx(ctx, "not a client context");
  		goto err;
  	}
  
  	if (servername != NULL) {
  		if ((ctx->servername = strdup(servername)) == NULL) {
  			tls_set_errorx(ctx, "out of memory");
  			goto err;
  		}
  
  		/*
  		 * If there's a trailing dot, remove it. While an FQDN includes
  		 * the terminating dot representing the zero-length label of
  		 * the root (RFC 8499, section 2), the SNI explicitly does not
  		 * include it (RFC 6066, section 3).
  		 */
  		servername_len = strlen(ctx->servername);
  		if (servername_len > 0 &&
  		    ctx->servername[servername_len - 1] == '.')
  			ctx->servername[servername_len - 1] = '\0';
  	}
  
  	if ((ctx->ssl_ctx = SSL_CTX_new(SSLv23_client_method())) == NULL) {
  		tls_set_errorx(ctx, "ssl context failure");
  		goto err;
  	}
  
  	if (tls_configure_ssl(ctx, ctx->ssl_ctx) != 0)
  		goto err;
  
  	if (tls_configure_ssl_keypair(ctx, ctx->ssl_ctx,
  	    ctx->config->keypair, 0) != 0)
  		goto err;
  
  	if (ctx->config->verify_name) {
  		if (ctx->servername == NULL) {
  			tls_set_errorx(ctx, "server name not specified");
  			goto err;
  		}
  	}
  
  	if (tls_configure_ssl_verify(ctx, ctx->ssl_ctx, SSL_VERIFY_PEER) == -1)
  		goto err;
  
  	if (ctx->config->ecdhecurves != NULL) {
  		if (SSL_CTX_set1_groups(ctx->ssl_ctx, ctx->config->ecdhecurves,
  		    ctx->config->ecdhecurves_len) != 1) {
  			tls_set_errorx(ctx, "failed to set ecdhe curves");
  			goto err;
  		}
  	}
  
  	if (SSL_CTX_set_tlsext_status_cb(ctx->ssl_ctx, tls_ocsp_verify_cb) != 1) {
  		tls_set_errorx(ctx, "ssl OCSP verification setup failure");
  		goto err;
  	}
  
  	if ((ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) {
  		tls_set_errorx(ctx, "ssl connection failure");
  		goto err;
  	}
  
  	if (SSL_set_app_data(ctx->ssl_conn, ctx) != 1) {
  		tls_set_errorx(ctx, "ssl application data failure");
  		goto err;
  	}
  
  	if (ctx->config->session_fd != -1) {
  		SSL_clear_options(ctx->ssl_conn, SSL_OP_NO_TICKET);
  		if (tls_client_read_session(ctx) == -1)
  			goto err;
  	}
  
  	if (SSL_set_tlsext_status_type(ctx->ssl_conn, TLSEXT_STATUSTYPE_ocsp) != 1) {
  		tls_set_errorx(ctx, "ssl OCSP extension setup failure");
  		goto err;
  	}
  
  	/*
  	 * RFC 6066 (SNI): Literal IPv4 and IPv6 addresses are not
  	 * permitted in "HostName".
  	 */
  	if (ctx->servername != NULL &&
  	    inet_pton(AF_INET, ctx->servername, &addrbuf) != 1 &&
  	    inet_pton(AF_INET6, ctx->servername, &addrbuf) != 1) {
  		if (SSL_set_tlsext_host_name(ctx->ssl_conn,
  		    ctx->servername) == 0) {
  			tls_set_errorx(ctx, "server name indication failure");
  			goto err;
  		}
  	}
  
  	ctx->state |= TLS_CONNECTED;
  	rv = 0;
  
   err:
  	return (rv);
  }
  
  int
  tls_connect_socket(struct tls *ctx, int s, const char *servername)
  {
  	return tls_connect_fds(ctx, s, s, servername);
  }
  
  int
  tls_connect_fds(struct tls *ctx, int fd_read, int fd_write,
      const char *servername)
  {
  	int rv = -1;
  
  	if (fd_read < 0 || fd_write < 0) {
  		tls_set_errorx(ctx, "invalid file descriptors");
  		goto err;
  	}
  
  	if (tls_connect_common(ctx, servername) != 0)
  		goto err;
  
  	if (SSL_set_rfd(ctx->ssl_conn, fd_read) != 1 ||
  	    SSL_set_wfd(ctx->ssl_conn, fd_write) != 1) {
  		tls_set_errorx(ctx, "ssl file descriptor failure");
  		goto err;
  	}
  
  	rv = 0;
   err:
  	return (rv);
  }
  
  int
  tls_connect_cbs(struct tls *ctx, tls_read_cb read_cb,
      tls_write_cb write_cb, void *cb_arg, const char *servername)
  {
  	int rv = -1;
  
  	if (tls_connect_common(ctx, servername) != 0)
  		goto err;
  
  	if (tls_set_cbs(ctx, read_cb, write_cb, cb_arg) != 0)
  		goto err;
  
  	rv = 0;
  
   err:
  	return (rv);
  }
  
  int
  tls_handshake_client(struct tls *ctx)
  {
  	X509 *cert = NULL;
  	int match, ssl_ret;
  	int rv = -1;
  
  	if ((ctx->flags & TLS_CLIENT) == 0) {
  		tls_set_errorx(ctx, "not a client context");
  		goto err;
  	}
  
  	if ((ctx->state & TLS_CONNECTED) == 0) {
  		tls_set_errorx(ctx, "context not connected");
  		goto err;
  	}
  
  	ctx->state |= TLS_SSL_NEEDS_SHUTDOWN;
  
  	ERR_clear_error();
  	if ((ssl_ret = SSL_connect(ctx->ssl_conn)) != 1) {
  		rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "handshake");
  		goto err;
  	}
  
  	if (ctx->config->verify_name) {
  		cert = SSL_get_peer_certificate(ctx->ssl_conn);
  		if (cert == NULL) {
  			tls_set_errorx(ctx, "no server certificate");
  			goto err;
  		}
  		if (tls_check_name(ctx, cert, ctx->servername, &match) == -1)
  			goto err;
  		if (!match) {
  			tls_set_errorx(ctx, "name `%s' not present in"
  			    " server certificate", ctx->servername);
  			goto err;
  		}
  	}
  
  	ctx->state |= TLS_HANDSHAKE_COMPLETE;
  
  	if (ctx->config->session_fd != -1) {
  		if (tls_client_write_session(ctx) == -1)
  			goto err;
  	}
  
  	rv = 0;
  
   err:
  	X509_free(cert);
  
  	return (rv);
  }