2 * Copyright notice from original mutt:
3 * Copyright (C) 1999-2001 Tommi Komulainen <Tommi.Komulainen@iki.fi>
5 * This file is part of mutt-ng, see http://www.muttng.org/.
6 * It's licensed under the GNU General Public License,
7 * please see the file GPL in the top level source directory.
16 #include <openssl/ssl.h>
17 #include <openssl/x509.h>
18 #include <openssl/err.h>
19 #include <openssl/rand.h>
23 #include <lib-lib/mem.h>
24 #include <lib-lib/str.h>
25 #include <lib-lib/macros.h>
28 #include "mutt_socket.h"
29 #include "mutt_menu.h"
30 #include "mutt_curses.h"
33 #include "lib/debug.h"
35 #if OPENSSL_VERSION_NUMBER >= 0x00904000L
36 #define READ_X509_KEY(fp, key) PEM_read_X509(fp, key, NULL, NULL)
38 #define READ_X509_KEY(fp, key) PEM_read_X509(fp, key, NULL)
41 /* Just in case OpenSSL doesn't define DEVRANDOM */
43 #define DEVRANDOM "/dev/urandom"
46 /* This is ugly, but as RAND_status came in on OpenSSL version 0.9.5
47 * and the code has to support older versions too, this is seemed to
48 * be cleaner way compared to having even uglier #ifdefs all around.
50 #ifdef HAVE_RAND_STATUS
51 #define HAVE_ENTROPY() (RAND_status() == 1)
53 static int entropy_byte_count = 0;
55 /* OpenSSL fills the entropy pool from /dev/urandom if it exists */
56 #define HAVE_ENTROPY() (!access(DEVRANDOM, R_OK) || entropy_byte_count >= 16)
59 typedef struct _sslsockdata {
65 /* local prototypes */
66 static int ssl_init (void);
67 static int add_entropy (const char *file);
68 static int ssl_socket_read (CONNECTION * conn, char *buf, size_t len);
69 static int ssl_socket_write (CONNECTION * conn, const char *buf, size_t len);
70 static int ssl_socket_open (CONNECTION * conn);
71 static int ssl_socket_close (CONNECTION * conn);
72 static int tls_close (CONNECTION * conn);
73 static int ssl_check_certificate (sslsockdata * data);
74 static void ssl_get_client_cert (sslsockdata * ssldata, CONNECTION * conn);
75 static int ssl_passwd_cb (char *buf, int size, int rwflag, void *userdata);
76 static int ssl_negotiate (sslsockdata *);
78 /* mutt_ssl_starttls: Negotiate TLS over an already opened connection.
79 * TODO: Merge this code better with ssl_socket_open. */
80 int mutt_ssl_starttls (CONNECTION * conn)
88 ssldata = p_new(sslsockdata, 1);
89 /* the ssl_use_xxx protocol options don't apply. We must use TLS in TLS. */
90 if (!(ssldata->ctx = SSL_CTX_new (TLSv1_client_method ()))) {
91 debug_print (1, ("Error allocating SSL_CTX\n"));
95 ssl_get_client_cert (ssldata, conn);
97 if (!(ssldata->ssl = SSL_new (ssldata->ctx))) {
98 debug_print (1, ("Error allocating SSL\n"));
102 if (SSL_set_fd (ssldata->ssl, conn->fd) != 1) {
103 debug_print (1, ("Error setting fd\n"));
107 if (ssl_negotiate (ssldata))
110 /* hmm. watch out if we're starting TLS over any method other than raw. */
111 conn->sockdata = ssldata;
112 conn->conn_read = ssl_socket_read;
113 conn->conn_write = ssl_socket_write;
114 conn->conn_close = tls_close;
116 conn->ssf = SSL_CIPHER_get_bits (SSL_get_current_cipher (ssldata->ssl),
122 p_delete(&ssldata->ssl);
124 p_delete(&ssldata->ctx);
132 * OpenSSL library needs to be fed with sufficient entropy. On systems
133 * with /dev/urandom, this is done transparently by the library itself,
134 * on other systems we need to fill the entropy pool ourselves.
136 * Even though only OpenSSL 0.9.5 and later will complain about the
137 * lack of entropy, we try to our best and fill the pool with older
138 * versions also. (That's the reason for the ugly #ifdefs and macros,
139 * otherwise I could have simply #ifdef'd the whole ssl_init funcion)
141 static int ssl_init (void)
143 char path[_POSIX_PATH_MAX];
144 static unsigned char init_complete = 0;
149 if (!HAVE_ENTROPY ()) {
150 /* load entropy from files */
151 add_entropy (SslEntropyFile);
152 add_entropy (RAND_file_name (path, sizeof (path)));
154 /* load entropy from egd sockets */
156 add_entropy (getenv ("EGDSOCKET"));
157 snprintf (path, sizeof (path), "%s/.entropy", NONULL (Homedir));
159 add_entropy ("/tmp/entropy");
162 /* shuffle $RANDFILE (or ~/.rnd if unset) */
163 RAND_write_file (RAND_file_name (path, sizeof (path)));
165 if (!HAVE_ENTROPY ()) {
166 mutt_error (_("Failed to find enough entropy on your system"));
172 /* I don't think you can do this just before reading the error. The call
173 * itself might clobber the last SSL error. */
174 SSL_load_error_strings ();
180 static int add_entropy (const char *file)
188 if (stat (file, &st) == -1)
189 return errno == ENOENT ? 0 : -1;
191 mutt_message (_("Filling entropy pool: %s...\n"), file);
193 /* check that the file permissions are secure */
194 if (st.st_uid != getuid () ||
195 ((st.st_mode & (S_IWGRP | S_IRGRP)) != 0) ||
196 ((st.st_mode & (S_IWOTH | S_IROTH)) != 0)) {
197 mutt_error (_("%s has insecure permissions!"), file);
206 n = RAND_load_file (file, -1);
208 #ifndef HAVE_RAND_STATUS
210 entropy_byte_count += n;
215 static int ssl_socket_open_err (CONNECTION * conn)
217 mutt_error (_("SSL disabled due the lack of entropy"));
223 int mutt_ssl_socket_setup (CONNECTION * conn)
225 if (ssl_init () < 0) {
226 conn->conn_open = ssl_socket_open_err;
230 conn->conn_open = ssl_socket_open;
231 conn->conn_read = ssl_socket_read;
232 conn->conn_write = ssl_socket_write;
233 conn->conn_close = ssl_socket_close;
238 static int ssl_socket_read (CONNECTION * conn, char *buf, size_t len)
240 sslsockdata *data = conn->sockdata;
242 return SSL_read (data->ssl, buf, len);
245 static int ssl_socket_write (CONNECTION * conn, const char *buf, size_t len)
247 sslsockdata *data = conn->sockdata;
249 return SSL_write (data->ssl, buf, len);
252 static int ssl_socket_open (CONNECTION * conn)
257 if (raw_socket_open (conn) < 0)
260 data = p_new(sslsockdata, 1);
261 conn->sockdata = data;
263 data->ctx = SSL_CTX_new (SSLv23_client_method ());
265 /* disable SSL protocols as needed */
266 if (!option (OPTTLSV1)) {
267 SSL_CTX_set_options (data->ctx, SSL_OP_NO_TLSv1);
269 if (!option (OPTSSLV2)) {
270 SSL_CTX_set_options (data->ctx, SSL_OP_NO_SSLv2);
272 if (!option (OPTSSLV3)) {
273 SSL_CTX_set_options (data->ctx, SSL_OP_NO_SSLv3);
276 ssl_get_client_cert (data, conn);
278 data->ssl = SSL_new (data->ctx);
279 SSL_set_fd (data->ssl, conn->fd);
281 if (ssl_negotiate (data)) {
282 mutt_socket_close (conn);
286 conn->ssf = SSL_CIPHER_get_bits (SSL_get_current_cipher (data->ssl),
292 /* ssl_negotiate: After SSL state has been initialised, attempt to negotiate
293 * SSL over the wire, including certificate checks. */
294 static int ssl_negotiate (sslsockdata * ssldata)
299 #if OPENSSL_VERSION_NUMBER >= 0x00906000L
300 /* This only exists in 0.9.6 and above. Without it we may get interrupted
301 * reads or writes. Bummer. */
302 SSL_set_mode (ssldata->ssl, SSL_MODE_AUTO_RETRY);
305 if ((err = SSL_connect (ssldata->ssl)) != 1) {
306 switch (SSL_get_error (ssldata->ssl, err)) {
307 case SSL_ERROR_SYSCALL:
308 errmsg = _("I/O error");
311 errmsg = ERR_error_string (ERR_get_error (), NULL);
314 errmsg = _("unknown error");
317 mutt_error (_("SSL failed: %s"), errmsg);
323 ssldata->cert = SSL_get_peer_certificate (ssldata->ssl);
324 if (!ssldata->cert) {
325 mutt_error (_("Unable to get certificate from peer"));
330 if (!ssl_check_certificate (ssldata))
333 mutt_message (_("SSL connection using %s (%s)"),
334 SSL_get_cipher_version (ssldata->ssl),
335 SSL_get_cipher_name (ssldata->ssl));
341 static int ssl_socket_close (CONNECTION * conn)
343 sslsockdata *data = conn->sockdata;
346 SSL_shutdown (data->ssl);
348 X509_free (data->cert);
350 SSL_free (data->ssl);
351 SSL_CTX_free (data->ctx);
352 p_delete(&conn->sockdata);
355 return raw_socket_close (conn);
358 static int compare_certificates (X509 *cert, X509 *peercert,
359 unsigned char *peermd,
360 unsigned int peermdlen) {
361 unsigned char md[EVP_MAX_MD_SIZE];
364 /* Avoid CPU-intensive digest calculation if the certificates are
365 * not even remotely equal.
367 if (X509_subject_name_cmp (cert, peercert) != 0 ||
368 X509_issuer_name_cmp (cert, peercert) != 0)
371 if (!X509_digest (cert, EVP_sha1(), md, &mdlen) || peermdlen != mdlen)
374 if (memcmp(peermd, md, mdlen) != 0)
380 static int check_certificate_cache (X509 *peercert) {
381 unsigned char peermd[EVP_MAX_MD_SIZE];
382 unsigned int peermdlen;
386 if (!X509_digest (peercert, EVP_sha1(), peermd, &peermdlen))
389 for (scert = SslSessionCerts; scert; scert = scert->next) {
390 cert = *(X509**)scert->data;
391 if (!compare_certificates (cert, peercert, peermd, peermdlen)) {
398 static int tls_close (CONNECTION * conn)
402 rc = ssl_socket_close (conn);
403 conn->conn_read = raw_socket_read;
404 conn->conn_write = raw_socket_write;
405 conn->conn_close = raw_socket_close;
410 static char *x509_get_part (char *line, const char *ndx)
412 static char ret[SHORT_STRING];
415 strfcpy (ret, _("Unknown"), sizeof (ret));
417 c = strstr (line, ndx);
420 c2 = strchr (c, '/');
423 strfcpy (ret, c, sizeof (ret));
431 static void x509_fingerprint (char *s, int l, X509 * cert)
433 unsigned char md[EVP_MAX_MD_SIZE];
437 if (!X509_digest (cert, EVP_md5 (), md, &n)) {
438 m_strcpy(s, l, _("[unable to calculate]"));
441 for (j = 0; j < (int) n; j++) {
444 snprintf(ch, 8, "%02X%s", md[j], (j % 2 ? " " : ""));
450 static char *asn1time_to_string (ASN1_UTCTIME * tm)
455 strfcpy (buf, _("[invalid date]"), sizeof (buf));
457 bio = BIO_new (BIO_s_mem ());
459 if (ASN1_TIME_print (bio, tm))
460 (void) BIO_read (bio, buf, sizeof (buf));
467 static int check_certificate_by_signer (X509 * peercert)
473 ctx = X509_STORE_new ();
477 if (option (OPTSSLSYSTEMCERTS)) {
478 if (X509_STORE_set_default_paths (ctx))
481 debug_print (2, ("X509_STORE_set_default_paths failed\n"));
484 if (X509_STORE_load_locations (ctx, SslCertFile, NULL))
487 debug_print (2, ("X509_STORE_load_locations_failed\n"));
491 X509_STORE_free (ctx);
495 X509_STORE_CTX_init (&xsc, ctx, peercert, NULL);
497 pass = (X509_verify_cert (&xsc) > 0);
500 char buf[SHORT_STRING];
503 err = X509_STORE_CTX_get_error (&xsc);
504 snprintf (buf, sizeof (buf), "%s (%d)",
505 X509_verify_cert_error_string (err), err);
506 debug_print (2, ("X509_verify_cert: %s\n", buf));
509 X509_STORE_CTX_cleanup (&xsc);
510 X509_STORE_free (ctx);
515 static int check_certificate_by_digest (X509 * peercert)
517 unsigned char peermd[EVP_MAX_MD_SIZE];
518 unsigned int peermdlen;
523 /* expiration check */
524 if (X509_cmp_current_time (X509_get_notBefore (peercert)) >= 0) {
525 debug_print (2, ("Server certificate is not yet valid\n"));
526 mutt_error (_("Server certificate is not yet valid"));
530 if (X509_cmp_current_time (X509_get_notAfter (peercert)) <= 0) {
531 debug_print (2, ("Server certificate has expired\n"));
532 mutt_error (_("Server certificate has expired"));
537 if ((fp = fopen (SslCertFile, "rt")) == NULL)
540 if (!X509_digest (peercert, EVP_sha1 (), peermd, &peermdlen)) {
545 while ((cert = READ_X509_KEY (fp, &cert)) != NULL) {
546 pass = compare_certificates (cert, peercert, peermd, peermdlen) ? 0 : 1;
556 static int ssl_check_certificate (sslsockdata * data)
558 char *part[] = { "/CN=", "/Email=", "/O=", "/OU=", "/L=", "/ST=", "/C=" };
559 char helpstr[SHORT_STRING];
560 char buf[SHORT_STRING];
564 char *name = NULL, *c;
566 /* check session cache first */
567 if (check_certificate_cache (data->cert)) {
568 debug_print (1, ("ssl_check_certificate: using cached certificate\n"));
572 if (check_certificate_by_signer (data->cert)) {
573 debug_print (1, ("signer check passed\n"));
577 /* automatic check from user's database */
578 if (SslCertFile && check_certificate_by_digest (data->cert)) {
579 debug_print (1, ("digest check passed\n"));
583 /* interactive check from user */
584 menu = mutt_new_menu ();
586 menu->dialog = p_new(char *, menu->max);
587 for (i = 0; i < menu->max; i++)
588 menu->dialog[i] = p_new(char, SHORT_STRING);
591 strfcpy (menu->dialog[row], _("This certificate belongs to:"),
594 name = X509_NAME_oneline (X509_get_subject_name (data->cert),
596 for (i = 0; i < 5; i++) {
597 c = x509_get_part (name, part[i]);
598 snprintf (menu->dialog[row++], SHORT_STRING, " %s", c);
602 strfcpy (menu->dialog[row], _("This certificate was issued by:"),
605 name = X509_NAME_oneline (X509_get_issuer_name (data->cert),
607 for (i = 0; i < 5; i++) {
608 c = x509_get_part (name, part[i]);
609 snprintf (menu->dialog[row++], SHORT_STRING, " %s", c);
613 snprintf (menu->dialog[row++], SHORT_STRING, "%s",
614 _("This certificate is valid"));
615 snprintf (menu->dialog[row++], SHORT_STRING, _(" from %s"),
616 asn1time_to_string (X509_get_notBefore (data->cert)));
617 snprintf (menu->dialog[row++], SHORT_STRING, _(" to %s"),
618 asn1time_to_string (X509_get_notAfter (data->cert)));
622 x509_fingerprint (buf, sizeof (buf), data->cert);
623 snprintf (menu->dialog[row++], SHORT_STRING, _("Fingerprint: %s"), buf);
625 menu->title = _("SSL Certificate check");
627 if (SslCertFile && X509_cmp_current_time (X509_get_notAfter (data->cert)) >= 0
628 && X509_cmp_current_time (X509_get_notBefore (data->cert)) < 0) {
629 menu->prompt = _("(r)eject, accept (o)nce, (a)ccept always");
630 menu->keys = _("roa");
633 menu->prompt = _("(r)eject, accept (o)nce");
634 menu->keys = _("ro");
638 mutt_make_help (buf, sizeof (buf), _("Exit "), MENU_GENERIC, OP_EXIT);
639 m_strcat(helpstr, sizeof(helpstr), buf);
640 mutt_make_help (buf, sizeof (buf), _("Help"), MENU_GENERIC, OP_HELP);
641 m_strcat(helpstr, sizeof(helpstr), buf);
642 menu->help = helpstr;
645 set_option (OPTUNBUFFEREDINPUT);
647 switch (mutt_menuLoop (menu)) {
649 case OP_MAX + 1: /* reject */
653 case OP_MAX + 3: /* accept always */
655 if ((fp = fopen (SslCertFile, "a"))) {
656 if (PEM_write_X509 (fp, data->cert))
661 mutt_error (_("Warning: Couldn't save certificate"));
665 mutt_message (_("Certificate saved"));
669 case OP_MAX + 2: /* accept once */
671 /* keep a handle on accepted certificates in case we want to
672 * open up another connection to the same server in this session */
673 SslSessionCerts = mutt_add_list_n (SslSessionCerts, &data->cert,
678 unset_option (OPTUNBUFFEREDINPUT);
679 mutt_menuDestroy (&menu);
683 static void ssl_get_client_cert (sslsockdata * ssldata, CONNECTION * conn)
686 debug_print (2, ("Using client certificate %s\n", SslClientCert));
687 SSL_CTX_set_default_passwd_cb_userdata (ssldata->ctx, &conn->account);
688 SSL_CTX_set_default_passwd_cb (ssldata->ctx, ssl_passwd_cb);
689 SSL_CTX_use_certificate_file (ssldata->ctx, SslClientCert,
691 SSL_CTX_use_PrivateKey_file (ssldata->ctx, SslClientCert,
696 static int ssl_passwd_cb (char *buf, int size, int rwflag, void *userdata)
698 ACCOUNT *account = (ACCOUNT *) userdata;
700 if (mutt_account_getuser (account))
703 debug_print (2, ("getting password for %s@%s:%u\n",
704 account->user, account->host, account->port));
706 if (mutt_account_getpass (account))
709 return snprintf (buf, size, "%s", account->pass);