xref: /netbsd-src/usr.bin/ftp/ssl.c (revision f68d28ccb5df2dfe20ddb2c038cc8840e47295bd)
1 /*	$NetBSD: ssl.c,v 1.16 2023/05/16 18:52:09 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1998-2004 Dag-Erling Coïdan Smørgrav
5  * Copyright (c) 2008, 2010 Joerg Sonnenberger <joerg@NetBSD.org>
6  * Copyright (c) 2015 Thomas Klausner <wiz@NetBSD.org>
7  * Copyright (c) 2023 Michael van Elst <mlelstv@NetBSD.org>
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer
15  *    in this position and unchanged.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  *
33  * $FreeBSD: common.c,v 1.53 2007/12/19 00:26:36 des Exp $
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 __RCSID("$NetBSD: ssl.c,v 1.16 2023/05/16 18:52:09 christos Exp $");
39 #endif
40 
41 #include <err.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <stdarg.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <time.h>
49 #include <unistd.h>
50 
51 #include <sys/param.h>
52 #include <sys/uio.h>
53 
54 #include <netinet/tcp.h>
55 #include <netinet/in.h>
56 
57 #ifdef WITH_SSL
58 #include <openssl/crypto.h>
59 #include <openssl/x509.h>
60 #include <openssl/pem.h>
61 #include <openssl/ssl.h>
62 #include <openssl/err.h>
63 #endif
64 
65 #include "ssl.h"
66 #include "ftp_var.h"
67 
68 extern int quit_time, verbose, ftp_debug;
69 extern FILE *ttyout;
70 
71 struct fetch_connect {
72 	int			 sd;		/* file/socket descriptor */
73 	char			*buf;		/* buffer */
74 	size_t			 bufsize;	/* buffer size */
75 	size_t			 bufpos;	/* position of buffer */
76 	size_t			 buflen;	/* length of buffer contents */
77 	struct {				/* data cached after an
78 						   interrupted read */
79 		char	*buf;
80 		size_t	 size;
81 		size_t	 pos;
82 		size_t	 len;
83 	} cache;
84 	int 			 issock;
85 	int			 iserr;
86 	int			 iseof;
87 #ifdef WITH_SSL
88 	SSL			*ssl;		/* SSL handle */
89 #endif
90 };
91 
92 /*
93  * Write a vector to a connection w/ timeout
94  * Note: can modify the iovec.
95  */
96 static ssize_t
97 fetch_writev(struct fetch_connect *conn, struct iovec *iov, int iovcnt)
98 {
99 	struct timeval timeout, now, delta;
100 	ssize_t len, total;
101 	int fd = conn->sd;
102 	int rv, timeout_secs;
103 	struct pollfd pfd[1];
104 
105 	pfd[0].fd = fd;
106 	pfd[0].events = POLLOUT;
107 	gettimeofday(&timeout, NULL);
108 	timeout.tv_sec += quit_time;
109 
110 	total = 0;
111 	while (iovcnt > 0) {
112 		if (quit_time > 0) {	/* enforce timeout */
113 			do {
114 				(void)gettimeofday(&now, NULL);
115 				timersub(&timeout, &now, &delta);
116 				timeout_secs = delta.tv_sec * 1000 + delta.tv_usec/1000;
117 				if (timeout_secs < 0)
118 					timeout_secs = 0;
119 				rv = ftp_poll(pfd, 1, timeout_secs);
120 					/* loop until poll !EINTR && !EAGAIN */
121 			} while (rv == -1 && (errno == EINTR || errno == EAGAIN));
122 			if (rv == -1)
123 				return -1;
124 			if (rv == 0) {
125 				errno = ETIMEDOUT;
126 				return -1;
127 			}
128 		}
129 		errno = 0;
130 #ifdef WITH_SSL
131 		if (conn->ssl != NULL)
132 			len = SSL_write(conn->ssl, iov->iov_base, iov->iov_len);
133 		else
134 #endif
135 			len = writev(fd, iov, iovcnt);
136 		if (len == 0) {
137 			/* we consider a short write a failure */
138 			/* XXX perhaps we shouldn't in the SSL case */
139 			errno = EPIPE;
140 			return -1;
141 		}
142 		if (len < 0) {
143 			if (errno == EINTR || errno == EAGAIN)
144 				continue;
145 			return -1;
146 		}
147 		total += len;
148 		while (iovcnt > 0 && len >= (ssize_t)iov->iov_len) {
149 			len -= iov->iov_len;
150 			iov++;
151 			iovcnt--;
152 		}
153 		if (iovcnt > 0) {
154 			iov->iov_len -= len;
155 			iov->iov_base = (char *)iov->iov_base + len;
156 		}
157 	}
158 	return total;
159 }
160 
161 static ssize_t
162 fetch_write(const void *str, size_t len, struct fetch_connect *conn)
163 {
164 	struct iovec iov[1];
165 
166 	iov[0].iov_base = (char *)__UNCONST(str);
167 	iov[0].iov_len = len;
168 	return fetch_writev(conn, iov, 1);
169 }
170 
171 /*
172  * Send a formatted line; optionally echo to terminal
173  */
174 int
175 fetch_printf(struct fetch_connect *conn, const char *fmt, ...)
176 {
177 	va_list ap;
178 	size_t len;
179 	char *msg;
180 	int r;
181 
182 	va_start(ap, fmt);
183 	len = vasprintf(&msg, fmt, ap);
184 	va_end(ap);
185 
186 	if (msg == NULL) {
187 		errno = ENOMEM;
188 		return -1;
189 	}
190 
191 	r = fetch_write(msg, len, conn);
192 	free(msg);
193 	return r;
194 }
195 
196 int
197 fetch_fileno(struct fetch_connect *conn)
198 {
199 
200 	return conn->sd;
201 }
202 
203 int
204 fetch_error(struct fetch_connect *conn)
205 {
206 
207 	return conn->iserr;
208 }
209 
210 static void
211 fetch_clearerr(struct fetch_connect *conn)
212 {
213 
214 	conn->iserr = 0;
215 }
216 
217 int
218 fetch_flush(struct fetch_connect *conn)
219 {
220 
221 	if (conn->issock) {
222 		int fd = conn->sd;
223 		int v;
224 #ifdef TCP_NOPUSH
225 		v = 0;
226 		setsockopt(fd, IPPROTO_TCP, TCP_NOPUSH, &v, sizeof(v));
227 #endif
228 		v = 1;
229 		setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
230 	}
231 	return 0;
232 }
233 
234 /*ARGSUSED*/
235 struct fetch_connect *
236 fetch_open(const char *fname, const char *fmode)
237 {
238 	struct fetch_connect *conn;
239 	int fd;
240 
241 	fd = open(fname, O_RDONLY); /* XXX: fmode */
242 	if (fd < 0)
243 		return NULL;
244 
245 	if ((conn = calloc(1, sizeof(*conn))) == NULL) {
246 		close(fd);
247 		return NULL;
248 	}
249 
250 	conn->sd = fd;
251 	conn->issock = 0;
252 	return conn;
253 }
254 
255 /*ARGSUSED*/
256 struct fetch_connect *
257 fetch_fdopen(int sd, const char *fmode)
258 {
259 	struct fetch_connect *conn;
260 #if defined(SO_NOSIGPIPE) || defined(TCP_NOPUSH)
261 	int opt = 1;
262 #endif
263 
264 	if ((conn = calloc(1, sizeof(*conn))) == NULL)
265 		return NULL;
266 
267 	conn->sd = sd;
268 	conn->issock = 1;
269 	fcntl(sd, F_SETFD, FD_CLOEXEC);
270 #ifdef SO_NOSIGPIPE
271 	setsockopt(sd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
272 #endif
273 #ifdef TCP_NOPUSH
274 	setsockopt(sd, IPPROTO_TCP, TCP_NOPUSH, &opt, sizeof(opt));
275 #endif
276 	return conn;
277 }
278 
279 int
280 fetch_close(struct fetch_connect *conn)
281 {
282 	if (conn == NULL)
283 		return 0;
284 
285 	fetch_flush(conn);
286 #ifdef WITH_SSL
287 	SSL_free(conn->ssl);
288 #endif
289 	close(conn->sd);
290 	free(conn->cache.buf);
291 	free(conn->buf);
292 	free(conn);
293 	return 0;
294 }
295 
296 #define FETCH_WRITE_WAIT	-3
297 #define FETCH_READ_WAIT		-2
298 #define FETCH_READ_ERROR	-1
299 
300 #ifdef WITH_SSL
301 static ssize_t
302 fetch_ssl_read(SSL *ssl, void *buf, size_t len)
303 {
304 	ssize_t rlen;
305 	rlen = SSL_read(ssl, buf, len);
306 	if (rlen >= 0)
307 		return rlen;
308 
309 	switch (SSL_get_error(ssl, rlen)) {
310 	case SSL_ERROR_WANT_READ:
311 		return FETCH_READ_WAIT;
312 	case SSL_ERROR_WANT_WRITE:
313 		return FETCH_WRITE_WAIT;
314 	default:
315 		ERR_print_errors_fp(ttyout);
316 		return FETCH_READ_ERROR;
317 	}
318 }
319 #endif /* WITH_SSL */
320 
321 static ssize_t
322 fetch_nonssl_read(int sd, void *buf, size_t len)
323 {
324 	ssize_t rlen;
325 
326 	rlen = read(sd, buf, len);
327 	if (rlen == -1) {
328 		if (errno == EINTR || errno == EAGAIN)
329 			return FETCH_READ_WAIT;
330 		return FETCH_READ_ERROR;
331 	}
332 	return rlen;
333 }
334 
335 /*
336  * Cache some data that was read from a socket but cannot be immediately
337  * returned because of an interrupted system call.
338  */
339 static int
340 fetch_cache_data(struct fetch_connect *conn, char *src, size_t nbytes)
341 {
342 
343 	if (conn->cache.size < nbytes) {
344 		char *tmp = realloc(conn->cache.buf, nbytes);
345 		if (tmp == NULL)
346 			return -1;
347 
348 		conn->cache.buf = tmp;
349 		conn->cache.size = nbytes;
350 	}
351 
352 	memcpy(conn->cache.buf, src, nbytes);
353 	conn->cache.len = nbytes;
354 	conn->cache.pos = 0;
355 	return 0;
356 }
357 
358 static int
359 fetch_wait(struct fetch_connect *conn, ssize_t rlen, struct timeval *timeout)
360 {
361 	struct timeval now, delta;
362 	int fd = conn->sd;
363 	int rv, timeout_secs;
364 	struct pollfd pfd[1];
365 
366 	pfd[0].fd = fd;
367 	if (rlen == FETCH_READ_WAIT) {
368 		pfd[0].events = POLLIN;
369 	} else if (rlen == FETCH_WRITE_WAIT) {
370 		pfd[0].events = POLLOUT;
371 	} else {
372 		pfd[0].events = 0;
373 	}
374 
375 	do {
376 		if (quit_time > 0) {
377 			gettimeofday(&now, NULL);
378 			timersub(timeout, &now, &delta);
379 			timeout_secs = delta.tv_sec * 1000 + delta.tv_usec/1000;
380 			if (timeout_secs < 0)
381 				timeout_secs = 0;
382 		} else {
383 			timeout_secs = INFTIM;
384 		}
385 		errno = 0;
386 		rv = ftp_poll(pfd, 1, timeout_secs);
387 				/* loop until poll !EINTR && !EAGAIN */
388 	} while (rv == -1 && (errno == EINTR || errno == EAGAIN));
389 	if (rv == 0) {		/* poll timeout */
390 		fprintf(ttyout, "\r\n%s: transfer aborted"
391 		    " because stalled for %lu sec.\r\n",
392 		    getprogname(), (unsigned long)quit_time);
393 		errno = ETIMEDOUT;
394 		conn->iserr = ETIMEDOUT;
395 		return -1;
396 	}
397 	if (rv == -1) {		/* poll error */
398 		conn->iserr = errno;
399 		return -1;
400 	}
401 	return 0;
402 }
403 
404 size_t
405 fetch_read(void *ptr, size_t size, size_t nmemb, struct fetch_connect *conn)
406 {
407 	ssize_t rlen, total;
408 	size_t len;
409 	char *start, *buf;
410 	struct timeval timeout;
411 
412 	if (quit_time > 0) {
413 		gettimeofday(&timeout, NULL);
414 		timeout.tv_sec += quit_time;
415 	}
416 
417 	total = 0;
418 	start = buf = ptr;
419 	len = size * nmemb;
420 
421 	if (conn->cache.len > 0) {
422 		/*
423 		 * The last invocation of fetch_read was interrupted by a
424 		 * signal after some data had been read from the socket. Copy
425 		 * the cached data into the supplied buffer before trying to
426 		 * read from the socket again.
427 		 */
428 		total = (conn->cache.len < len) ? conn->cache.len : len;
429 		memcpy(buf, conn->cache.buf, total);
430 
431 		conn->cache.len -= total;
432 		conn->cache.pos += total;
433 		len -= total;
434 		buf += total;
435 	}
436 
437 	while (len > 0) {
438 		/*
439 		 * The socket is non-blocking.  Instead of the canonical
440 		 * poll() -> read(), we do the following:
441 		 *
442 		 * 1) call read() or SSL_read().
443 		 * 2) if an error occurred, return -1.
444 		 * 3) if we received data but we still expect more,
445 		 *    update our counters and loop.
446 		 * 4) if read() or SSL_read() signaled EOF, return.
447 		 * 5) if we did not receive any data but we're not at EOF,
448 		 *    call poll().
449 		 *
450 		 * In the SSL case, this is necessary because if we
451 		 * receive a close notification, we have to call
452 		 * SSL_read() one additional time after we've read
453 		 * everything we received.
454 		 *
455 		 * In the non-SSL case, it may improve performance (very
456 		 * slightly) when reading small amounts of data.
457 		 */
458 #ifdef WITH_SSL
459 		if (conn->ssl != NULL)
460 			rlen = fetch_ssl_read(conn->ssl, buf, len);
461 		else
462 #endif
463 			rlen = fetch_nonssl_read(conn->sd, buf, len);
464 		switch (rlen) {
465 		case 0:
466 			conn->iseof = 1;
467 			return total;
468 		case FETCH_READ_ERROR:
469 			conn->iserr = errno;
470 			if (errno == EINTR || errno == EAGAIN)
471 				fetch_cache_data(conn, start, total);
472 			return 0;
473 		case FETCH_READ_WAIT:
474 		case FETCH_WRITE_WAIT:
475 			if (fetch_wait(conn, rlen, &timeout) == -1)
476 				return 0;
477 			break;
478 		default:
479 			len -= rlen;
480 			buf += rlen;
481 			total += rlen;
482 			break;
483 		}
484 	}
485 	return total;
486 }
487 
488 #define MIN_BUF_SIZE 1024
489 
490 /*
491  * Read a line of text from a connection w/ timeout
492  */
493 char *
494 fetch_getln(char *str, int size, struct fetch_connect *conn)
495 {
496 	size_t tmpsize;
497 	size_t len;
498 	char c;
499 
500 	if (conn->buf == NULL) {
501 		if ((conn->buf = malloc(MIN_BUF_SIZE)) == NULL) {
502 			errno = ENOMEM;
503 			conn->iserr = 1;
504 			return NULL;
505 		}
506 		conn->bufsize = MIN_BUF_SIZE;
507 	}
508 
509 	if (conn->iserr || conn->iseof)
510 		return NULL;
511 
512 	if (conn->buflen - conn->bufpos > 0)
513 		goto done;
514 
515 	conn->buf[0] = '\0';
516 	conn->bufpos = 0;
517 	conn->buflen = 0;
518 	do {
519 		len = fetch_read(&c, sizeof(c), 1, conn);
520 		if (len == 0) {
521 			if (conn->iserr)
522 				return NULL;
523 			if (conn->iseof)
524 				break;
525 			abort();
526 		}
527 		conn->buf[conn->buflen++] = c;
528 		if (conn->buflen == conn->bufsize) {
529 			char *tmp = conn->buf;
530 			tmpsize = conn->bufsize * 2 + 1;
531 			if ((tmp = realloc(tmp, tmpsize)) == NULL) {
532 				errno = ENOMEM;
533 				conn->iserr = 1;
534 				return NULL;
535 			}
536 			conn->buf = tmp;
537 			conn->bufsize = tmpsize;
538 		}
539 	} while (c != '\n');
540 
541 	if (conn->buflen == 0)
542 		return NULL;
543  done:
544 	tmpsize = MIN(size - 1, (int)(conn->buflen - conn->bufpos));
545 	memcpy(str, conn->buf + conn->bufpos, tmpsize);
546 	str[tmpsize] = '\0';
547 	conn->bufpos += tmpsize;
548 	return str;
549 }
550 
551 int
552 fetch_getline(struct fetch_connect *conn, char *buf, size_t buflen,
553     const char **errormsg)
554 {
555 	size_t len;
556 	int rv;
557 
558 	if (fetch_getln(buf, buflen, conn) == NULL) {
559 		if (conn->iseof) {	/* EOF */
560 			rv = -2;
561 			if (errormsg)
562 				*errormsg = "\nEOF received";
563 		} else {		/* error */
564 			rv = -1;
565 			if (errormsg)
566 				*errormsg = "Error encountered";
567 		}
568 		fetch_clearerr(conn);
569 		return rv;
570 	}
571 	len = strlen(buf);
572 	if (buf[len - 1] == '\n') {	/* clear any trailing newline */
573 		buf[--len] = '\0';
574 	} else if (len == buflen - 1) {	/* line too long */
575 		while (1) {
576 			char c;
577 			size_t rlen = fetch_read(&c, sizeof(c), 1, conn);
578 			if (rlen == 0 || c == '\n')
579 				break;
580 		}
581 		if (errormsg)
582 			*errormsg = "Input line is too long";
583 		fetch_clearerr(conn);
584 		return -3;
585 	}
586 	if (errormsg)
587 		*errormsg = NULL;
588 	return len;
589 }
590 
591 #ifdef WITH_SSL
592 /*
593  * Start the SSL/TLS negotiation.
594  * Socket fcntl flags are temporarily updated to include O_NONBLOCK;
595  * these will not be reverted on connection failure.
596  * Returns pointer to allocated SSL structure on success,
597  * or NULL upon failure.
598  */
599 void *
600 fetch_start_ssl(int sock, const char *servername)
601 {
602 	SSL *ssl = NULL;
603 	SSL_CTX *ctx = NULL;
604 	X509_VERIFY_PARAM *param;
605 	int ret, ssl_err, flags, rv, timeout_secs;
606 	int verify = !ftp_truthy("sslnoverify", getoptionvalue("sslnoverify"), 0);
607 	struct timeval timeout, now, delta;
608 	struct pollfd pfd[1];
609 
610 	/* Init the SSL library and context */
611 	if (!SSL_library_init()){
612 		warnx("SSL library init failed");
613 		goto cleanup_start_ssl;
614 	}
615 
616 	SSL_load_error_strings();
617 
618 	ctx = SSL_CTX_new(SSLv23_client_method());
619 	SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
620 	if (verify) {
621 		SSL_CTX_set_default_verify_paths(ctx);
622 		SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
623 	}
624 
625 	ssl = SSL_new(ctx);
626 	if (ssl == NULL){
627 		warnx("SSL context creation failed");
628 		goto cleanup_start_ssl;
629 	}
630 
631 	if (verify) {
632 		param = SSL_get0_param(ssl);
633 		if (!X509_VERIFY_PARAM_set1_host(param, servername,
634 		    strlen(servername))) {
635 			warnx("SSL verification setup failed");
636 			goto cleanup_start_ssl;
637 		}
638 
639 		/* Enable peer verification, (using the default callback) */
640 		SSL_set_verify(ssl, SSL_VERIFY_PEER, NULL);
641 	}
642 #ifdef SSL_OP_IGNORE_UNEXPECTED_EOF
643 	SSL_set_options(ssl, SSL_OP_IGNORE_UNEXPECTED_EOF);
644 #endif
645 
646 						/* save current socket flags */
647 	if ((flags = fcntl(sock, F_GETFL, 0)) == -1) {
648 		warn("Can't %s socket flags for SSL connect to `%s'",
649 		    "save", servername);
650 		goto cleanup_start_ssl;
651 	}
652 						/* set non-blocking connect */
653 	if (fcntl(sock, F_SETFL, flags | O_NONBLOCK) == -1) {
654 		warn("Can't set socket non-blocking for SSL connect to `%s'",
655 		    servername);
656 		goto cleanup_start_ssl;
657 	}
658 
659 	/* NOTE: we now must restore socket flags on successful connection */
660 
661 	(void)gettimeofday(&timeout, NULL);	/* setup SSL_connect() timeout */
662 	timeout.tv_sec += (quit_time > 0) ? quit_time: 60;
663 						/* without -q, default to 60s */
664 
665 	SSL_set_fd(ssl, sock);
666 	if (!SSL_set_tlsext_host_name(ssl, __UNCONST(servername))) {
667 		warnx("SSL hostname setting failed");
668 		goto cleanup_start_ssl;
669 	}
670 	pfd[0].fd = sock;
671 	pfd[0].events = 0;
672 	while ((ret = SSL_connect(ssl)) <= 0) {
673 		ssl_err = SSL_get_error(ssl, ret);
674 		DPRINTF("%s: SSL_connect() ret=%d ssl_err=%d\n",
675 		    __func__, ret, ssl_err);
676 		if (ret == 0) { /* unsuccessful handshake */
677 			ERR_print_errors_fp(ttyout);
678 			goto cleanup_start_ssl;
679 		}
680 		if (ssl_err == SSL_ERROR_WANT_READ) {
681 			pfd[0].events = POLLIN;
682 		} else if (ssl_err == SSL_ERROR_WANT_WRITE) {
683 			pfd[0].events = POLLOUT;
684 		} else {
685 			ERR_print_errors_fp(ttyout);
686 			goto cleanup_start_ssl;
687 		}
688 		(void)gettimeofday(&now, NULL);
689 		timersub(&timeout, &now, &delta);
690 		timeout_secs = delta.tv_sec * 1000 + delta.tv_usec/1000;
691 		if (timeout_secs < 0)
692 			timeout_secs = 0;
693 		rv = ftp_poll(pfd, 1, timeout_secs);
694 		if (rv == 0) {		/* poll for SSL_connect() timed out */
695 			fprintf(ttyout, "Timeout establishing SSL connection to `%s'\n",
696 			    servername);
697 			goto cleanup_start_ssl;
698 		} else if (rv == -1 && errno != EINTR && errno != EAGAIN) {
699 			warn("Error polling for SSL connect to `%s'", servername);
700 			goto cleanup_start_ssl;
701 		}
702 	}
703 
704 	if (fcntl(sock, F_SETFL, flags) == -1) {
705 						/* restore socket flags */
706 		warn("Can't %s socket flags for SSL connect to `%s'",
707 		    "restore", servername);
708 		goto cleanup_start_ssl;
709 	}
710 
711 	if (ftp_debug && verbose) {
712 		X509 *cert;
713 		X509_NAME *name;
714 		char *str;
715 
716 		fprintf(ttyout, "SSL connection established using %s\n",
717 		    SSL_get_cipher(ssl));
718 		cert = SSL_get_peer_certificate(ssl);
719 		name = X509_get_subject_name(cert);
720 		str = X509_NAME_oneline(name, 0, 0);
721 		fprintf(ttyout, "Certificate subject: %s\n", str);
722 		free(str);
723 		name = X509_get_issuer_name(cert);
724 		str = X509_NAME_oneline(name, 0, 0);
725 		fprintf(ttyout, "Certificate issuer: %s\n", str);
726 		free(str);
727 	}
728 
729 	return ssl;
730 
731  cleanup_start_ssl:
732 	if (ssl)
733 		SSL_free(ssl);
734 	if (ctx)
735 		SSL_CTX_free(ctx);
736 	return NULL;
737 }
738 #endif /* WITH_SSL */
739 
740 
741 void
742 fetch_set_ssl(struct fetch_connect *conn, void *ssl)
743 {
744 #ifdef WITH_SSL
745 	conn->ssl = ssl;
746 #endif
747 }
748