1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Portions Copyright (c) The OpenSSL Project 1999 */
10 /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
11 library. It is #included into the tls.c file when that library is used. The
12 code herein is based on a patch that was originally contributed by Steve
13 Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara.
15 No cryptographic code is included in Exim. All this module does is to call
16 functions from the OpenSSL library. */
21 #include <openssl/lhash.h>
22 #include <openssl/ssl.h>
23 #include <openssl/err.h>
24 #include <openssl/rand.h>
25 #ifndef OPENSSL_NO_ECDH
26 # include <openssl/ec.h>
29 # include <openssl/ocsp.h>
31 #ifdef EXPERIMENTAL_DANE
37 # define EXIM_OCSP_SKEW_SECONDS (300L)
38 # define EXIM_OCSP_MAX_AGE (-1L)
41 #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
42 # define EXIM_HAVE_OPENSSL_TLSEXT
44 #if OPENSSL_VERSION_NUMBER >= 0x00908000L
45 # define EXIM_HAVE_RSA_GENKEY_EX
47 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
48 # define EXIM_HAVE_OCSP_RESP_COUNT
50 # define EXIM_HAVE_EPHEM_RSA_KEX
51 # define EXIM_HAVE_RAND_PSEUDO
53 #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
54 # define EXIM_HAVE_SHA256
58 * X509_check_host provides sane certificate hostname checking, but was added
59 * to OpenSSL late, after other projects forked off the code-base. So in
60 * addition to guarding against the base version number, beware that LibreSSL
61 * does not (at this time) support this function.
63 * If LibreSSL gains a different API, perhaps via libtls, then we'll probably
64 * opt to disentangle and ask a LibreSSL user to provide glue for a third
65 * crypto provider for libtls instead of continuing to tie the OpenSSL glue
66 * into even twistier knots. If LibreSSL gains the same API, we can just
67 * change this guard and punt the issue for a while longer.
69 #ifndef LIBRESSL_VERSION_NUMBER
70 # if OPENSSL_VERSION_NUMBER >= 0x010100000L
71 # define EXIM_HAVE_OPENSSL_CHECKHOST
72 # define EXIM_HAVE_OPENSSL_DH_BITS
74 # if OPENSSL_VERSION_NUMBER >= 0x010000000L \
75 && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L
76 # define EXIM_HAVE_OPENSSL_CHECKHOST
80 #if !defined(LIBRESSL_VERSION_NUMBER) \
81 || LIBRESSL_VERSION_NUMBER >= 0x20010000L
82 # if !defined(OPENSSL_NO_ECDH)
83 # if OPENSSL_VERSION_NUMBER >= 0x0090800fL
84 # define EXIM_HAVE_ECDH
86 # if OPENSSL_VERSION_NUMBER >= 0x10002000L
87 # define EXIM_HAVE_OPENSSL_EC_NIST2NID
92 #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP)
93 # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile"
97 #ifdef EXIM_HAVE_OPENSSL_CHECKHOST
98 # include <openssl/x509v3.h>
101 /* Structure for collecting random data for seeding. */
103 typedef struct randstuff
{
108 /* Local static variables */
110 static BOOL client_verify_callback_called
= FALSE
;
111 static BOOL server_verify_callback_called
= FALSE
;
112 static const uschar
*sid_ctx
= US
"exim";
114 /* We have three different contexts to care about.
116 Simple case: client, `client_ctx`
117 As a client, we can be doing a callout or cut-through delivery while receiving
118 a message. So we have a client context, which should have options initialised
119 from the SMTP Transport.
122 There are two cases: with and without ServerNameIndication from the client.
123 Given TLS SNI, we can be using different keys, certs and various other
124 configuration settings, because they're re-expanded with $tls_sni set. This
125 allows vhosting with TLS. This SNI is sent in the handshake.
126 A client might not send SNI, so we need a fallback, and an initial setup too.
127 So as a server, we start out using `server_ctx`.
128 If SNI is sent by the client, then we as server, mid-negotiation, try to clone
129 `server_sni` from `server_ctx` and then initialise settings by re-expanding
133 static SSL_CTX
*client_ctx
= NULL
;
134 static SSL_CTX
*server_ctx
= NULL
;
135 static SSL
*client_ssl
= NULL
;
136 static SSL
*server_ssl
= NULL
;
138 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
139 static SSL_CTX
*server_sni
= NULL
;
142 static char ssl_errstring
[256];
144 static int ssl_session_timeout
= 200;
145 static BOOL client_verify_optional
= FALSE
;
146 static BOOL server_verify_optional
= FALSE
;
148 static BOOL reexpand_tls_files_for_sni
= FALSE
;
151 typedef struct tls_ext_ctx_cb
{
156 STACK_OF(X509
) *verify_stack
; /* chain for verifying the proof */
160 uschar
*file_expanded
;
161 OCSP_RESPONSE
*response
;
164 X509_STORE
*verify_store
; /* non-null if status requested */
165 BOOL verify_required
;
170 /* these are cached from first expand */
171 uschar
*server_cipher_list
;
172 /* only passed down to tls_error: */
174 const uschar
* verify_cert_hostnames
;
175 #ifndef DISABLE_EVENT
176 uschar
* event_action
;
180 /* should figure out a cleanup of API to handle state preserved per
181 implementation, for various reasons, which can be void * in the APIs.
182 For now, we hack around it. */
183 tls_ext_ctx_cb
*client_static_cbinfo
= NULL
;
184 tls_ext_ctx_cb
*server_static_cbinfo
= NULL
;
187 setup_certs(SSL_CTX
*sctx
, uschar
*certs
, uschar
*crl
, host_item
*host
, BOOL optional
,
188 int (*cert_vfy_cb
)(int, X509_STORE_CTX
*), uschar
** errstr
);
191 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
192 static int tls_servername_cb(SSL
*s
, int *ad ARG_UNUSED
, void *arg
);
195 static int tls_server_stapling_cb(SSL
*s
, void *arg
);
199 /*************************************************
201 *************************************************/
203 /* Called from lots of places when errors occur before actually starting to do
204 the TLS handshake, that is, while the session is still in clear. Always returns
205 DEFER for a server and FAIL for a client so that most calls can use "return
206 tls_error(...)" to do this processing and then give an appropriate return. A
207 single function is used for both server and client, because it is called from
208 some shared functions.
211 prefix text to include in the logged error
212 host NULL if setting up a server;
213 the connected host if setting up a client
214 msg error message or NULL if we should ask OpenSSL
215 errstr pointer to output error message
217 Returns: OK/DEFER/FAIL
221 tls_error(uschar
* prefix
, const host_item
* host
, uschar
* msg
, uschar
** errstr
)
225 ERR_error_string(ERR_get_error(), ssl_errstring
);
226 msg
= US ssl_errstring
;
229 if (errstr
) *errstr
= string_sprintf("(%s): %s", prefix
, msg
);
230 return host
? FAIL
: DEFER
;
235 /*************************************************
236 * Callback to generate RSA key *
237 *************************************************/
241 s SSL connection (not used)
245 Returns: pointer to generated key
249 rsa_callback(SSL
*s
, int export
, int keylength
)
252 #ifdef EXIM_HAVE_RSA_GENKEY_EX
253 BIGNUM
*bn
= BN_new();
256 export
= export
; /* Shut picky compilers up */
257 DEBUG(D_tls
) debug_printf("Generating %d bit RSA key...\n", keylength
);
259 #ifdef EXIM_HAVE_RSA_GENKEY_EX
260 if ( !BN_set_word(bn
, (unsigned long)RSA_F4
)
261 || !(rsa_key
= RSA_new())
262 || !RSA_generate_key_ex(rsa_key
, keylength
, bn
, NULL
)
265 if (!(rsa_key
= RSA_generate_key(keylength
, RSA_F4
, NULL
, NULL
)))
269 ERR_error_string(ERR_get_error(), ssl_errstring
);
270 log_write(0, LOG_MAIN
|LOG_PANIC
, "TLS error (RSA_generate_key): %s",
282 x509_store_dump_cert_s_names(X509_STORE * store)
284 STACK_OF(X509_OBJECT) * roots= store->objs;
286 static uschar name[256];
288 for(i= 0; i<sk_X509_OBJECT_num(roots); i++)
290 X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
291 if(tmp_obj->type == X509_LU_X509)
293 X509 * current_cert= tmp_obj->data.x509;
294 X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name));
295 name[sizeof(name)-1] = '\0';
296 debug_printf(" %s\n", name);
304 #ifndef DISABLE_EVENT
306 verify_event(tls_support
* tlsp
, X509
* cert
, int depth
, const uschar
* dn
,
307 BOOL
*calledp
, const BOOL
*optionalp
, const uschar
* what
)
313 ev
= tlsp
== &tls_out
? client_static_cbinfo
->event_action
: event_action
;
316 DEBUG(D_tls
) debug_printf("verify_event: %s %d\n", what
, depth
);
317 old_cert
= tlsp
->peercert
;
318 tlsp
->peercert
= X509_dup(cert
);
319 /* NB we do not bother setting peerdn */
320 if ((yield
= event_raise(ev
, US
"tls:cert", string_sprintf("%d", depth
))))
322 log_write(0, LOG_MAIN
, "[%s] %s verify denied by event-action: "
323 "depth=%d cert=%s: %s",
324 tlsp
== &tls_out
? deliver_host_address
: sender_host_address
,
325 what
, depth
, dn
, yield
);
329 if (old_cert
) tlsp
->peercert
= old_cert
; /* restore 1st failing cert */
330 return 1; /* reject (leaving peercert set) */
332 DEBUG(D_tls
) debug_printf("Event-action verify failure overridden "
333 "(host in tls_try_verify_hosts)\n");
335 X509_free(tlsp
->peercert
);
336 tlsp
->peercert
= old_cert
;
342 /*************************************************
343 * Callback for verification *
344 *************************************************/
346 /* The SSL library does certificate verification if set up to do so. This
347 callback has the current yes/no state is in "state". If verification succeeded,
348 we set the certificate-verified flag. If verification failed, what happens
349 depends on whether the client is required to present a verifiable certificate
352 If verification is optional, we change the state to yes, but still log the
353 verification error. For some reason (it really would help to have proper
354 documentation of OpenSSL), this callback function then gets called again, this
355 time with state = 1. We must take care not to set the private verified flag on
356 the second time through.
358 Note: this function is not called if the client fails to present a certificate
359 when asked. We get here only if a certificate has been received. Handling of
360 optional verification for this case is done when requesting SSL to verify, by
361 setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case.
363 May be called multiple times for different issues with a certificate, even
364 for a given "depth" in the certificate chain.
367 preverify_ok current yes/no state as 1/0
368 x509ctx certificate information.
369 tlsp per-direction (client vs. server) support data
370 calledp has-been-called flag
371 optionalp verification-is-optional flag
373 Returns: 0 if verification should fail, otherwise 1
377 verify_callback(int preverify_ok
, X509_STORE_CTX
*x509ctx
,
378 tls_support
*tlsp
, BOOL
*calledp
, BOOL
*optionalp
)
380 X509
* cert
= X509_STORE_CTX_get_current_cert(x509ctx
);
381 int depth
= X509_STORE_CTX_get_error_depth(x509ctx
);
384 X509_NAME_oneline(X509_get_subject_name(cert
), CS dn
, sizeof(dn
));
385 dn
[sizeof(dn
)-1] = '\0';
387 if (preverify_ok
== 0)
389 uschar
* extra
= verify_mode
? string_sprintf(" (during %c-verify for [%s])",
390 *verify_mode
, sender_host_address
)
392 log_write(0, LOG_MAIN
, "[%s] SSL verify error%s: depth=%d error=%s cert=%s",
393 tlsp
== &tls_out
? deliver_host_address
: sender_host_address
,
395 X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx
)), dn
);
400 tlsp
->peercert
= X509_dup(cert
); /* record failing cert */
401 return 0; /* reject */
403 DEBUG(D_tls
) debug_printf("SSL verify failure overridden (host in "
404 "tls_try_verify_hosts)\n");
409 DEBUG(D_tls
) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth
, dn
);
411 if (tlsp
== &tls_out
&& client_static_cbinfo
->u_ocsp
.client
.verify_store
)
412 { /* client, wanting stapling */
413 /* Add the server cert's signing chain as the one
414 for the verification of the OCSP stapled information. */
416 if (!X509_STORE_add_cert(client_static_cbinfo
->u_ocsp
.client
.verify_store
,
419 sk_X509_push(client_static_cbinfo
->verify_stack
, cert
);
422 #ifndef DISABLE_EVENT
423 if (verify_event(tlsp
, cert
, depth
, dn
, calledp
, optionalp
, US
"SSL"))
424 return 0; /* reject, with peercert set */
429 const uschar
* verify_cert_hostnames
;
431 if ( tlsp
== &tls_out
432 && ((verify_cert_hostnames
= client_static_cbinfo
->verify_cert_hostnames
)))
433 /* client, wanting hostname check */
436 #ifdef EXIM_HAVE_OPENSSL_CHECKHOST
437 # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
438 # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
440 # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
441 # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
444 const uschar
* list
= verify_cert_hostnames
;
447 while ((name
= string_nextinlist(&list
, &sep
, NULL
, 0)))
448 if ((rc
= X509_check_host(cert
, CCS name
, 0,
449 X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
450 | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
,
455 log_write(0, LOG_MAIN
, "[%s] SSL verify error: internal error",
456 tlsp
== &tls_out
? deliver_host_address
: sender_host_address
);
463 if (!tls_is_name_for_cert(verify_cert_hostnames
, cert
))
466 uschar
* extra
= verify_mode
467 ? string_sprintf(" (during %c-verify for [%s])",
468 *verify_mode
, sender_host_address
)
470 log_write(0, LOG_MAIN
,
471 "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"",
472 tlsp
== &tls_out
? deliver_host_address
: sender_host_address
,
473 extra
, dn
, verify_cert_hostnames
);
478 tlsp
->peercert
= X509_dup(cert
); /* record failing cert */
479 return 0; /* reject */
481 DEBUG(D_tls
) debug_printf("SSL verify failure overridden (host in "
482 "tls_try_verify_hosts)\n");
486 #ifndef DISABLE_EVENT
487 if (verify_event(tlsp
, cert
, depth
, dn
, calledp
, optionalp
, US
"SSL"))
488 return 0; /* reject, with peercert set */
491 DEBUG(D_tls
) debug_printf("SSL%s verify ok: depth=0 SN=%s\n",
492 *calledp
? "" : " authenticated", dn
);
493 if (!*calledp
) tlsp
->certificate_verified
= TRUE
;
497 return 1; /* accept, at least for this level */
501 verify_callback_client(int preverify_ok
, X509_STORE_CTX
*x509ctx
)
503 return verify_callback(preverify_ok
, x509ctx
, &tls_out
,
504 &client_verify_callback_called
, &client_verify_optional
);
508 verify_callback_server(int preverify_ok
, X509_STORE_CTX
*x509ctx
)
510 return verify_callback(preverify_ok
, x509ctx
, &tls_in
,
511 &server_verify_callback_called
, &server_verify_optional
);
515 #ifdef EXPERIMENTAL_DANE
517 /* This gets called *by* the dane library verify callback, which interposes
521 verify_callback_client_dane(int preverify_ok
, X509_STORE_CTX
* x509ctx
)
523 X509
* cert
= X509_STORE_CTX_get_current_cert(x509ctx
);
525 int depth
= X509_STORE_CTX_get_error_depth(x509ctx
);
526 #ifndef DISABLE_EVENT
527 BOOL dummy_called
, optional
= FALSE
;
530 X509_NAME_oneline(X509_get_subject_name(cert
), CS dn
, sizeof(dn
));
531 dn
[sizeof(dn
)-1] = '\0';
533 DEBUG(D_tls
) debug_printf("verify_callback_client_dane: %s depth %d %s\n",
534 preverify_ok
? "ok":"BAD", depth
, dn
);
536 #ifndef DISABLE_EVENT
537 if (verify_event(&tls_out
, cert
, depth
, dn
,
538 &dummy_called
, &optional
, US
"DANE"))
539 return 0; /* reject, with peercert set */
542 if (preverify_ok
== 1)
543 tls_out
.dane_verified
=
544 tls_out
.certificate_verified
= TRUE
;
547 int err
= X509_STORE_CTX_get_error(x509ctx
);
549 debug_printf(" - err %d '%s'\n", err
, X509_verify_cert_error_string(err
));
550 if (err
== X509_V_ERR_APPLICATION_VERIFICATION
)
556 #endif /*EXPERIMENTAL_DANE*/
559 /*************************************************
560 * Information callback *
561 *************************************************/
563 /* The SSL library functions call this from time to time to indicate what they
564 are doing. We copy the string to the debugging output when TLS debugging has
576 info_callback(SSL
*s
, int where
, int ret
)
580 DEBUG(D_tls
) debug_printf("SSL info: %s\n", SSL_state_string_long(s
));
585 /*************************************************
586 * Initialize for DH *
587 *************************************************/
589 /* If dhparam is set, expand it, and load up the parameters for DH encryption.
592 sctx The current SSL CTX (inbound or outbound)
593 dhparam DH parameter file or fixed parameter identity string
594 host connected host, if client; NULL if server
595 errstr error string pointer
597 Returns: TRUE if OK (nothing to set up, or setup worked)
601 init_dh(SSL_CTX
*sctx
, uschar
*dhparam
, const host_item
*host
, uschar
** errstr
)
609 if (!expand_check(dhparam
, US
"tls_dhparam", &dhexpanded
, errstr
))
612 if (!dhexpanded
|| !*dhexpanded
)
613 bio
= BIO_new_mem_buf(CS
std_dh_prime_default(), -1);
614 else if (dhexpanded
[0] == '/')
616 if (!(bio
= BIO_new_file(CS dhexpanded
, "r")))
618 tls_error(string_sprintf("could not read dhparams file %s", dhexpanded
),
619 host
, US
strerror(errno
), errstr
);
625 if (Ustrcmp(dhexpanded
, "none") == 0)
627 DEBUG(D_tls
) debug_printf("Requested no DH parameters.\n");
631 if (!(pem
= std_dh_prime_named(dhexpanded
)))
633 tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded
),
634 host
, US
strerror(errno
), errstr
);
637 bio
= BIO_new_mem_buf(CS pem
, -1);
640 if (!(dh
= PEM_read_bio_DHparams(bio
, NULL
, NULL
, NULL
)))
643 tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded
),
648 /* note: our default limit of 2236 is not a multiple of 8; the limit comes from
649 * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with
650 * 2236. But older OpenSSL can only report in bytes (octets), not bits.
651 * If someone wants to dance at the edge, then they can raise the limit or use
652 * current libraries. */
653 #ifdef EXIM_HAVE_OPENSSL_DH_BITS
654 /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022
655 * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */
656 dh_bitsize
= DH_bits(dh
);
658 dh_bitsize
= 8 * DH_size(dh
);
661 /* Even if it is larger, we silently return success rather than cause things
662 * to fail out, so that a too-large DH will not knock out all TLS; it's a
663 * debatable choice. */
664 if (dh_bitsize
> tls_dh_max_bits
)
667 debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n",
668 dh_bitsize
, tls_dh_max_bits
);
672 SSL_CTX_set_tmp_dh(sctx
, dh
);
674 debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
675 dhexpanded
? dhexpanded
: US
"default", dh_bitsize
);
687 /*************************************************
688 * Initialize for ECDH *
689 *************************************************/
691 /* Load parameters for ECDH encryption.
693 For now, we stick to NIST P-256 because: it's simple and easy to configure;
694 it avoids any patent issues that might bite redistributors; despite events in
695 the news and concerns over curve choices, we're not cryptographers, we're not
696 pretending to be, and this is "good enough" to be better than no support,
697 protecting against most adversaries. Given another year or two, there might
698 be sufficient clarity about a "right" way forward to let us make an informed
699 decision, instead of a knee-jerk reaction.
701 Longer-term, we should look at supporting both various named curves and
702 external files generated with "openssl ecparam", much as we do for init_dh().
703 We should also support "none" as a value, to explicitly avoid initialisation.
708 sctx The current SSL CTX (inbound or outbound)
709 host connected host, if client; NULL if server
710 errstr error string pointer
712 Returns: TRUE if OK (nothing to set up, or setup worked)
716 init_ecdh(SSL_CTX
* sctx
, host_item
* host
, uschar
** errstr
)
718 #ifdef OPENSSL_NO_ECDH
727 if (host
) /* No ECDH setup for clients, only for servers */
730 # ifndef EXIM_HAVE_ECDH
732 debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
736 if (!expand_check(tls_eccurve
, US
"tls_eccurve", &exp_curve
, errstr
))
738 if (!exp_curve
|| !*exp_curve
)
741 /* "auto" needs to be handled carefully.
742 * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1
743 * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto
744 * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
745 * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
746 * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
748 if (Ustrcmp(exp_curve
, "auto") == 0)
750 #if OPENSSL_VERSION_NUMBER < 0x10002000L
751 DEBUG(D_tls
) debug_printf(
752 "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
753 exp_curve
= US
"prime256v1";
755 # if defined SSL_CTRL_SET_ECDH_AUTO
756 DEBUG(D_tls
) debug_printf(
757 "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n");
758 SSL_CTX_set_ecdh_auto(sctx
, 1);
761 DEBUG(D_tls
) debug_printf(
762 "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n");
768 DEBUG(D_tls
) debug_printf("ECDH: curve '%s'\n", exp_curve
);
769 if ( (nid
= OBJ_sn2nid (CCS exp_curve
)) == NID_undef
770 # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
771 && (nid
= EC_curve_nist2nid(CCS exp_curve
)) == NID_undef
775 tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve
),
780 if (!(ecdh
= EC_KEY_new_by_curve_name(nid
)))
782 tls_error(US
"Unable to create ec curve", host
, NULL
, errstr
);
786 /* The "tmp" in the name here refers to setting a temporary key
787 not to the stability of the interface. */
789 if ((rv
= SSL_CTX_set_tmp_ecdh(sctx
, ecdh
) == 0))
790 tls_error(string_sprintf("Error enabling '%s' curve", exp_curve
), host
, NULL
, errstr
);
792 DEBUG(D_tls
) debug_printf("ECDH: enabled '%s' curve\n", exp_curve
);
797 # endif /*EXIM_HAVE_ECDH*/
798 #endif /*OPENSSL_NO_ECDH*/
805 /*************************************************
806 * Load OCSP information into state *
807 *************************************************/
808 /* Called to load the server OCSP response from the given file into memory, once
809 caller has determined this is needed. Checks validity. Debugs a message
812 ASSUMES: single response, for single cert.
815 sctx the SSL_CTX* to update
816 cbinfo various parts of session state
817 expanded the filename putatively holding an OCSP response
822 ocsp_load_response(SSL_CTX
*sctx
, tls_ext_ctx_cb
*cbinfo
, const uschar
*expanded
)
825 OCSP_RESPONSE
* resp
;
826 OCSP_BASICRESP
* basic_response
;
827 OCSP_SINGLERESP
* single_response
;
828 ASN1_GENERALIZEDTIME
* rev
, * thisupd
, * nextupd
;
830 unsigned long verify_flags
;
831 int status
, reason
, i
;
833 cbinfo
->u_ocsp
.server
.file_expanded
= string_copy(expanded
);
834 if (cbinfo
->u_ocsp
.server
.response
)
836 OCSP_RESPONSE_free(cbinfo
->u_ocsp
.server
.response
);
837 cbinfo
->u_ocsp
.server
.response
= NULL
;
840 if (!(bio
= BIO_new_file(CS cbinfo
->u_ocsp
.server
.file_expanded
, "rb")))
842 DEBUG(D_tls
) debug_printf("Failed to open OCSP response file \"%s\"\n",
843 cbinfo
->u_ocsp
.server
.file_expanded
);
847 resp
= d2i_OCSP_RESPONSE_bio(bio
, NULL
);
851 DEBUG(D_tls
) debug_printf("Error reading OCSP response.\n");
855 if ((status
= OCSP_response_status(resp
)) != OCSP_RESPONSE_STATUS_SUCCESSFUL
)
857 DEBUG(D_tls
) debug_printf("OCSP response not valid: %s (%d)\n",
858 OCSP_response_status_str(status
), status
);
862 if (!(basic_response
= OCSP_response_get1_basic(resp
)))
865 debug_printf("OCSP response parse error: unable to extract basic response.\n");
869 sk
= cbinfo
->verify_stack
;
870 verify_flags
= OCSP_NOVERIFY
; /* check sigs, but not purpose */
872 /* May need to expose ability to adjust those flags?
873 OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
874 OCSP_TRUSTOTHER OCSP_NOINTERN */
876 /* This does a full verify on the OCSP proof before we load it for serving
877 up; possibly overkill - just date-checks might be nice enough.
879 OCSP_basic_verify takes a "store" arg, but does not
880 use it for the chain verification, which is all we do
881 when OCSP_NOVERIFY is set. The content from the wire
882 "basic_response" and a cert-stack "sk" are all that is used.
884 We have a stack, loaded in setup_certs() if tls_verify_certificates
885 was a file (not a directory, or "system"). It is unfortunate we
886 cannot used the connection context store, as that would neatly
887 handle the "system" case too, but there seems to be no library
888 function for getting a stack from a store.
889 [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ]
890 We do not free the stack since it could be needed a second time for
893 Separately we might try to replace using OCSP_basic_verify() - which seems to not
894 be a public interface into the OpenSSL library (there's no manual entry) -
895 But what with? We also use OCSP_basic_verify in the client stapling callback.
896 And there we NEED it; we must verify that status... unless the
897 library does it for us anyway? */
899 if ((i
= OCSP_basic_verify(basic_response
, sk
, NULL
, verify_flags
)) < 0)
903 ERR_error_string(ERR_get_error(), ssl_errstring
);
904 debug_printf("OCSP response verify failure: %s\n", US ssl_errstring
);
909 /* Here's the simplifying assumption: there's only one response, for the
910 one certificate we use, and nothing for anything else in a chain. If this
911 proves false, we need to extract a cert id from our issued cert
912 (tls_certificate) and use that for OCSP_resp_find_status() (which finds the
913 right cert in the stack and then calls OCSP_single_get0_status()).
915 I'm hoping to avoid reworking a bunch more of how we handle state here. */
917 if (!(single_response
= OCSP_resp_get0(basic_response
, 0)))
920 debug_printf("Unable to get first response from OCSP basic response.\n");
924 status
= OCSP_single_get0_status(single_response
, &reason
, &rev
, &thisupd
, &nextupd
);
925 if (status
!= V_OCSP_CERTSTATUS_GOOD
)
927 DEBUG(D_tls
) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
928 OCSP_cert_status_str(status
), status
,
929 OCSP_crl_reason_str(reason
), reason
);
933 if (!OCSP_check_validity(thisupd
, nextupd
, EXIM_OCSP_SKEW_SECONDS
, EXIM_OCSP_MAX_AGE
))
935 DEBUG(D_tls
) debug_printf("OCSP status invalid times.\n");
940 cbinfo
->u_ocsp
.server
.response
= resp
; /*XXX stack?*/
944 if (running_in_test_harness
)
946 extern char ** environ
;
948 if (environ
) for (p
= USS environ
; *p
; p
++)
949 if (Ustrncmp(*p
, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
951 DEBUG(D_tls
) debug_printf("Supplying known bad OCSP response\n");
952 goto supply_response
;
957 #endif /*!DISABLE_OCSP*/
962 /* Create and install a selfsigned certificate, for use in server mode */
965 tls_install_selfsign(SSL_CTX
* sctx
, uschar
** errstr
)
973 where
= US
"allocating pkey";
974 if (!(pkey
= EVP_PKEY_new()))
977 where
= US
"allocating cert";
978 if (!(x509
= X509_new()))
981 where
= US
"generating pkey";
982 if (!(rsa
= rsa_callback(NULL
, 0, 1024)))
985 where
= US
"assigning pkey";
986 if (!EVP_PKEY_assign_RSA(pkey
, rsa
))
989 X509_set_version(x509
, 2); /* N+1 - version 3 */
990 ASN1_INTEGER_set(X509_get_serialNumber(x509
), 0);
991 X509_gmtime_adj(X509_get_notBefore(x509
), 0);
992 X509_gmtime_adj(X509_get_notAfter(x509
), (long)60 * 60); /* 1 hour */
993 X509_set_pubkey(x509
, pkey
);
995 name
= X509_get_subject_name(x509
);
996 X509_NAME_add_entry_by_txt(name
, "C",
997 MBSTRING_ASC
, CUS
"UK", -1, -1, 0);
998 X509_NAME_add_entry_by_txt(name
, "O",
999 MBSTRING_ASC
, CUS
"Exim Developers", -1, -1, 0);
1000 X509_NAME_add_entry_by_txt(name
, "CN",
1001 MBSTRING_ASC
, CUS smtp_active_hostname
, -1, -1, 0);
1002 X509_set_issuer_name(x509
, name
);
1004 where
= US
"signing cert";
1005 if (!X509_sign(x509
, pkey
, EVP_md5()))
1008 where
= US
"installing selfsign cert";
1009 if (!SSL_CTX_use_certificate(sctx
, x509
))
1012 where
= US
"installing selfsign key";
1013 if (!SSL_CTX_use_PrivateKey(sctx
, pkey
))
1019 (void) tls_error(where
, NULL
, NULL
, errstr
);
1020 if (x509
) X509_free(x509
);
1021 if (pkey
) EVP_PKEY_free(pkey
);
1029 tls_add_certfile(SSL_CTX
* sctx
, tls_ext_ctx_cb
* cbinfo
, uschar
* file
,
1032 DEBUG(D_tls
) debug_printf("tls_certificate file %s\n", file
);
1033 if (!SSL_CTX_use_certificate_chain_file(sctx
, CS file
))
1034 return tls_error(string_sprintf(
1035 "SSL_CTX_use_certificate_chain_file file=%s", file
),
1036 cbinfo
->host
, NULL
, errstr
);
1041 tls_add_pkeyfile(SSL_CTX
* sctx
, tls_ext_ctx_cb
* cbinfo
, uschar
* file
,
1044 DEBUG(D_tls
) debug_printf("tls_privatekey file %s\n", file
);
1045 if (!SSL_CTX_use_PrivateKey_file(sctx
, CS file
, SSL_FILETYPE_PEM
))
1046 return tls_error(string_sprintf(
1047 "SSL_CTX_use_PrivateKey_file file=%s", file
), cbinfo
->host
, NULL
, errstr
);
1052 /*************************************************
1053 * Expand key and cert file specs *
1054 *************************************************/
1056 /* Called once during tls_init and possibly again during TLS setup, for a
1057 new context, if Server Name Indication was used and tls_sni was seen in
1058 the certificate string.
1061 sctx the SSL_CTX* to update
1062 cbinfo various parts of session state
1063 errstr error string pointer
1065 Returns: OK/DEFER/FAIL
1069 tls_expand_session_files(SSL_CTX
*sctx
, tls_ext_ctx_cb
*cbinfo
,
1074 if (!cbinfo
->certificate
)
1076 if (!cbinfo
->is_server
) /* client */
1079 if (tls_install_selfsign(sctx
, errstr
) != OK
)
1086 if (Ustrstr(cbinfo
->certificate
, US
"tls_sni") ||
1087 Ustrstr(cbinfo
->certificate
, US
"tls_in_sni") ||
1088 Ustrstr(cbinfo
->certificate
, US
"tls_out_sni")
1090 reexpand_tls_files_for_sni
= TRUE
;
1092 if (!expand_check(cbinfo
->certificate
, US
"tls_certificate", &expanded
, errstr
))
1096 if (cbinfo
->is_server
)
1098 const uschar
* file_list
= expanded
;
1102 while (file
= string_nextinlist(&file_list
, &sep
, NULL
, 0))
1103 if ((err
= tls_add_certfile(sctx
, cbinfo
, file
, errstr
)))
1106 else /* would there ever be a need for multiple client certs? */
1107 if ((err
= tls_add_certfile(sctx
, cbinfo
, expanded
, errstr
)))
1110 if (cbinfo
->privatekey
!= NULL
&&
1111 !expand_check(cbinfo
->privatekey
, US
"tls_privatekey", &expanded
, errstr
))
1114 /* If expansion was forced to fail, key_expanded will be NULL. If the result
1115 of the expansion is an empty string, ignore it also, and assume the private
1116 key is in the same file as the certificate. */
1118 if (expanded
&& *expanded
)
1119 if (cbinfo
->is_server
)
1121 const uschar
* file_list
= expanded
;
1125 while (file
= string_nextinlist(&file_list
, &sep
, NULL
, 0))
1126 if ((err
= tls_add_pkeyfile(sctx
, cbinfo
, file
, errstr
)))
1129 else /* would there ever be a need for multiple client certs? */
1130 if ((err
= tls_add_pkeyfile(sctx
, cbinfo
, expanded
, errstr
)))
1134 #ifndef DISABLE_OCSP
1135 if (cbinfo
->is_server
&& cbinfo
->u_ocsp
.server
.file
)
1138 if (!expand_check(cbinfo
->u_ocsp
.server
.file
, US
"tls_ocsp_file", &expanded
, errstr
))
1141 if (expanded
&& *expanded
)
1143 DEBUG(D_tls
) debug_printf("tls_ocsp_file %s\n", expanded
);
1144 if ( cbinfo
->u_ocsp
.server
.file_expanded
1145 && (Ustrcmp(expanded
, cbinfo
->u_ocsp
.server
.file_expanded
) == 0))
1147 DEBUG(D_tls
) debug_printf(" - value unchanged, using existing values\n");
1150 ocsp_load_response(sctx
, cbinfo
, expanded
);
1161 /*************************************************
1162 * Callback to handle SNI *
1163 *************************************************/
1165 /* Called when acting as server during the TLS session setup if a Server Name
1166 Indication extension was sent by the client.
1168 API documentation is OpenSSL s_server.c implementation.
1171 s SSL* of the current session
1172 ad unknown (part of OpenSSL API) (unused)
1173 arg Callback of "our" registered data
1175 Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
1178 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
1180 tls_servername_cb(SSL
*s
, int *ad ARG_UNUSED
, void *arg
)
1182 const char *servername
= SSL_get_servername(s
, TLSEXT_NAMETYPE_host_name
);
1183 tls_ext_ctx_cb
*cbinfo
= (tls_ext_ctx_cb
*) arg
;
1185 int old_pool
= store_pool
;
1186 uschar
* dummy_errstr
;
1189 return SSL_TLSEXT_ERR_OK
;
1191 DEBUG(D_tls
) debug_printf("Received TLS SNI \"%s\"%s\n", servername
,
1192 reexpand_tls_files_for_sni
? "" : " (unused for certificate selection)");
1194 /* Make the extension value available for expansion */
1195 store_pool
= POOL_PERM
;
1196 tls_in
.sni
= string_copy(US servername
);
1197 store_pool
= old_pool
;
1199 if (!reexpand_tls_files_for_sni
)
1200 return SSL_TLSEXT_ERR_OK
;
1202 /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually;
1203 not confident that memcpy wouldn't break some internal reference counting.
1204 Especially since there's a references struct member, which would be off. */
1206 if (!(server_sni
= SSL_CTX_new(SSLv23_server_method())))
1208 ERR_error_string(ERR_get_error(), ssl_errstring
);
1209 DEBUG(D_tls
) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring
);
1210 return SSL_TLSEXT_ERR_NOACK
;
1213 /* Not sure how many of these are actually needed, since SSL object
1214 already exists. Might even need this selfsame callback, for reneg? */
1216 SSL_CTX_set_info_callback(server_sni
, SSL_CTX_get_info_callback(server_ctx
));
1217 SSL_CTX_set_mode(server_sni
, SSL_CTX_get_mode(server_ctx
));
1218 SSL_CTX_set_options(server_sni
, SSL_CTX_get_options(server_ctx
));
1219 SSL_CTX_set_timeout(server_sni
, SSL_CTX_get_timeout(server_ctx
));
1220 SSL_CTX_set_tlsext_servername_callback(server_sni
, tls_servername_cb
);
1221 SSL_CTX_set_tlsext_servername_arg(server_sni
, cbinfo
);
1223 if ( !init_dh(server_sni
, cbinfo
->dhparam
, NULL
, &dummy_errstr
)
1224 || !init_ecdh(server_sni
, NULL
, &dummy_errstr
)
1226 return SSL_TLSEXT_ERR_NOACK
;
1228 if (cbinfo
->server_cipher_list
)
1229 SSL_CTX_set_cipher_list(server_sni
, CS cbinfo
->server_cipher_list
);
1230 #ifndef DISABLE_OCSP
1231 if (cbinfo
->u_ocsp
.server
.file
)
1233 SSL_CTX_set_tlsext_status_cb(server_sni
, tls_server_stapling_cb
);
1234 SSL_CTX_set_tlsext_status_arg(server_sni
, cbinfo
);
1238 if ((rc
= setup_certs(server_sni
, tls_verify_certificates
, tls_crl
, NULL
, FALSE
,
1239 verify_callback_server
, &dummy_errstr
)) != OK
)
1240 return SSL_TLSEXT_ERR_NOACK
;
1242 /* do this after setup_certs, because this can require the certs for verifying
1243 OCSP information. */
1244 if ((rc
= tls_expand_session_files(server_sni
, cbinfo
, &dummy_errstr
)) != OK
)
1245 return SSL_TLSEXT_ERR_NOACK
;
1247 DEBUG(D_tls
) debug_printf("Switching SSL context.\n");
1248 SSL_set_SSL_CTX(s
, server_sni
);
1250 return SSL_TLSEXT_ERR_OK
;
1252 #endif /* EXIM_HAVE_OPENSSL_TLSEXT */
1257 #ifndef DISABLE_OCSP
1259 /*************************************************
1260 * Callback to handle OCSP Stapling *
1261 *************************************************/
1263 /* Called when acting as server during the TLS session setup if the client
1264 requests OCSP information with a Certificate Status Request.
1266 Documentation via openssl s_server.c and the Apache patch from the OpenSSL
1272 tls_server_stapling_cb(SSL
*s
, void *arg
)
1274 const tls_ext_ctx_cb
*cbinfo
= (tls_ext_ctx_cb
*) arg
;
1275 uschar
*response_der
; /*XXX blob */
1276 int response_der_len
;
1278 /*XXX stack: use SSL_get_certificate() to see which cert; from that work
1279 out which ocsp blob to send. Unfortunately, SSL_get_certificate is known
1280 buggy in current OpenSSL; it returns the last cert loaded always rather than
1281 the one actually presented. So we can't support a stack of OCSP proofs at
1285 debug_printf("Received TLS status request (OCSP stapling); %s response\n",
1286 cbinfo
->u_ocsp
.server
.response
? "have" : "lack");
1288 tls_in
.ocsp
= OCSP_NOT_RESP
;
1289 if (!cbinfo
->u_ocsp
.server
.response
)
1290 return SSL_TLSEXT_ERR_NOACK
;
1292 response_der
= NULL
;
1293 response_der_len
= i2d_OCSP_RESPONSE(cbinfo
->u_ocsp
.server
.response
, /*XXX stack*/
1295 if (response_der_len
<= 0)
1296 return SSL_TLSEXT_ERR_NOACK
;
1298 SSL_set_tlsext_status_ocsp_resp(server_ssl
, response_der
, response_der_len
);
1299 tls_in
.ocsp
= OCSP_VFIED
;
1300 return SSL_TLSEXT_ERR_OK
;
1305 time_print(BIO
* bp
, const char * str
, ASN1_GENERALIZEDTIME
* time
)
1307 BIO_printf(bp
, "\t%s: ", str
);
1308 ASN1_GENERALIZEDTIME_print(bp
, time
);
1313 tls_client_stapling_cb(SSL
*s
, void *arg
)
1315 tls_ext_ctx_cb
* cbinfo
= arg
;
1316 const unsigned char * p
;
1318 OCSP_RESPONSE
* rsp
;
1319 OCSP_BASICRESP
* bs
;
1322 DEBUG(D_tls
) debug_printf("Received TLS status response (OCSP stapling):");
1323 len
= SSL_get_tlsext_status_ocsp_resp(s
, &p
);
1326 /* Expect this when we requested ocsp but got none */
1327 if (cbinfo
->u_ocsp
.client
.verify_required
&& LOGGING(tls_cipher
))
1328 log_write(0, LOG_MAIN
, "Received TLS status callback, null content");
1330 DEBUG(D_tls
) debug_printf(" null\n");
1331 return cbinfo
->u_ocsp
.client
.verify_required
? 0 : 1;
1334 if(!(rsp
= d2i_OCSP_RESPONSE(NULL
, &p
, len
)))
1336 tls_out
.ocsp
= OCSP_FAILED
;
1337 if (LOGGING(tls_cipher
))
1338 log_write(0, LOG_MAIN
, "Received TLS cert status response, parse error");
1340 DEBUG(D_tls
) debug_printf(" parse error\n");
1344 if(!(bs
= OCSP_response_get1_basic(rsp
)))
1346 tls_out
.ocsp
= OCSP_FAILED
;
1347 if (LOGGING(tls_cipher
))
1348 log_write(0, LOG_MAIN
, "Received TLS cert status response, error parsing response");
1350 DEBUG(D_tls
) debug_printf(" error parsing response\n");
1351 OCSP_RESPONSE_free(rsp
);
1355 /* We'd check the nonce here if we'd put one in the request. */
1356 /* However that would defeat cacheability on the server so we don't. */
1358 /* This section of code reworked from OpenSSL apps source;
1359 The OpenSSL Project retains copyright:
1360 Copyright (c) 1999 The OpenSSL Project. All rights reserved.
1365 ASN1_GENERALIZEDTIME
*rev
, *thisupd
, *nextupd
;
1367 DEBUG(D_tls
) bp
= BIO_new_fp(debug_file
, BIO_NOCLOSE
);
1369 /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */
1371 /* Use the chain that verified the server cert to verify the stapled info */
1372 /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */
1374 if ((i
= OCSP_basic_verify(bs
, cbinfo
->verify_stack
,
1375 cbinfo
->u_ocsp
.client
.verify_store
, 0)) <= 0)
1377 tls_out
.ocsp
= OCSP_FAILED
;
1378 if (LOGGING(tls_cipher
)) log_write(0, LOG_MAIN
,
1379 "Received TLS cert status response, itself unverifiable: %s",
1380 ERR_reason_error_string(ERR_peek_error()));
1381 BIO_printf(bp
, "OCSP response verify failure\n");
1382 ERR_print_errors(bp
);
1383 OCSP_RESPONSE_print(bp
, rsp
, 0);
1387 BIO_printf(bp
, "OCSP response well-formed and signed OK\n");
1389 /*XXX So we have a good stapled OCSP status. How do we know
1390 it is for the cert of interest? OpenSSL 1.1.0 has a routine
1391 OCSP_resp_find_status() which matches on a cert id, which presumably
1392 we should use. Making an id needs OCSP_cert_id_new(), which takes
1393 issuerName, issuerKey, serialNumber. Are they all in the cert?
1395 For now, carry on blindly accepting the resp. */
1398 OCSP_SINGLERESP
* single
;
1400 #ifdef EXIM_HAVE_OCSP_RESP_COUNT
1401 if (OCSP_resp_count(bs
) != 1)
1403 STACK_OF(OCSP_SINGLERESP
) * sresp
= bs
->tbsResponseData
->responses
;
1404 if (sk_OCSP_SINGLERESP_num(sresp
) != 1)
1407 tls_out
.ocsp
= OCSP_FAILED
;
1408 log_write(0, LOG_MAIN
, "OCSP stapling "
1409 "with multiple responses not handled");
1412 single
= OCSP_resp_get0(bs
, 0);
1413 status
= OCSP_single_get0_status(single
, &reason
, &rev
,
1414 &thisupd
, &nextupd
);
1417 DEBUG(D_tls
) time_print(bp
, "This OCSP Update", thisupd
);
1418 DEBUG(D_tls
) if(nextupd
) time_print(bp
, "Next OCSP Update", nextupd
);
1419 if (!OCSP_check_validity(thisupd
, nextupd
,
1420 EXIM_OCSP_SKEW_SECONDS
, EXIM_OCSP_MAX_AGE
))
1422 tls_out
.ocsp
= OCSP_FAILED
;
1423 DEBUG(D_tls
) ERR_print_errors(bp
);
1424 log_write(0, LOG_MAIN
, "Server OSCP dates invalid");
1428 DEBUG(D_tls
) BIO_printf(bp
, "Certificate status: %s\n",
1429 OCSP_cert_status_str(status
));
1432 case V_OCSP_CERTSTATUS_GOOD
:
1433 tls_out
.ocsp
= OCSP_VFIED
;
1436 case V_OCSP_CERTSTATUS_REVOKED
:
1437 tls_out
.ocsp
= OCSP_FAILED
;
1438 log_write(0, LOG_MAIN
, "Server certificate revoked%s%s",
1439 reason
!= -1 ? "; reason: " : "",
1440 reason
!= -1 ? OCSP_crl_reason_str(reason
) : "");
1441 DEBUG(D_tls
) time_print(bp
, "Revocation Time", rev
);
1444 tls_out
.ocsp
= OCSP_FAILED
;
1445 log_write(0, LOG_MAIN
,
1446 "Server certificate status unknown, in OCSP stapling");
1451 i
= cbinfo
->u_ocsp
.client
.verify_required
? 0 : 1;
1456 OCSP_RESPONSE_free(rsp
);
1459 #endif /*!DISABLE_OCSP*/
1462 /*************************************************
1463 * Initialize for TLS *
1464 *************************************************/
1466 /* Called from both server and client code, to do preliminary initialization
1467 of the library. We allocate and return a context structure.
1470 ctxp returned SSL context
1471 host connected host, if client; NULL if server
1472 dhparam DH parameter file
1473 certificate certificate file
1474 privatekey private key
1475 ocsp_file file of stapling info (server); flag for require ocsp (client)
1476 addr address if client; NULL if server (for some randomness)
1477 cbp place to put allocated callback context
1478 errstr error string pointer
1480 Returns: OK/DEFER/FAIL
1484 tls_init(SSL_CTX
**ctxp
, host_item
*host
, uschar
*dhparam
, uschar
*certificate
,
1486 #ifndef DISABLE_OCSP
1487 uschar
*ocsp_file
, /*XXX stack, in server*/
1489 address_item
*addr
, tls_ext_ctx_cb
** cbp
, uschar
** errstr
)
1494 tls_ext_ctx_cb
* cbinfo
;
1496 cbinfo
= store_malloc(sizeof(tls_ext_ctx_cb
));
1497 cbinfo
->certificate
= certificate
;
1498 cbinfo
->privatekey
= privatekey
;
1499 cbinfo
->is_server
= host
==NULL
;
1500 #ifndef DISABLE_OCSP
1501 cbinfo
->verify_stack
= NULL
;
1504 cbinfo
->u_ocsp
.server
.file
= ocsp_file
;
1505 cbinfo
->u_ocsp
.server
.file_expanded
= NULL
;
1506 cbinfo
->u_ocsp
.server
.response
= NULL
;
1509 cbinfo
->u_ocsp
.client
.verify_store
= NULL
;
1511 cbinfo
->dhparam
= dhparam
;
1512 cbinfo
->server_cipher_list
= NULL
;
1513 cbinfo
->host
= host
;
1514 #ifndef DISABLE_EVENT
1515 cbinfo
->event_action
= NULL
;
1518 SSL_load_error_strings(); /* basic set up */
1519 OpenSSL_add_ssl_algorithms();
1521 #ifdef EXIM_HAVE_SHA256
1522 /* SHA256 is becoming ever more popular. This makes sure it gets added to the
1523 list of available digests. */
1524 EVP_add_digest(EVP_sha256());
1527 /* Create a context.
1528 The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
1529 negotiation in the different methods; as far as I can tell, the only
1530 *_{server,client}_method which allows negotiation is SSLv23, which exists even
1531 when OpenSSL is built without SSLv2 support.
1532 By disabling with openssl_options, we can let admins re-enable with the
1535 if (!(ctx
= SSL_CTX_new(host
? SSLv23_client_method() : SSLv23_server_method())))
1536 return tls_error(US
"SSL_CTX_new", host
, NULL
, errstr
);
1538 /* It turns out that we need to seed the random number generator this early in
1539 order to get the full complement of ciphers to work. It took me roughly a day
1540 of work to discover this by experiment.
1542 On systems that have /dev/urandom, SSL may automatically seed itself from
1543 there. Otherwise, we have to make something up as best we can. Double check
1549 gettimeofday(&r
.tv
, NULL
);
1552 RAND_seed(US (&r
), sizeof(r
));
1553 RAND_seed(US big_buffer
, big_buffer_size
);
1554 if (addr
!= NULL
) RAND_seed(US addr
, sizeof(addr
));
1557 return tls_error(US
"RAND_status", host
,
1558 US
"unable to seed random number generator", errstr
);
1561 /* Set up the information callback, which outputs if debugging is at a suitable
1564 DEBUG(D_tls
) SSL_CTX_set_info_callback(ctx
, (void (*)())info_callback
);
1566 /* Automatically re-try reads/writes after renegotiation. */
1567 (void) SSL_CTX_set_mode(ctx
, SSL_MODE_AUTO_RETRY
);
1569 /* Apply administrator-supplied work-arounds.
1570 Historically we applied just one requested option,
1571 SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we
1572 moved to an administrator-controlled list of options to specify and
1573 grandfathered in the first one as the default value for "openssl_options".
1575 No OpenSSL version number checks: the options we accept depend upon the
1576 availability of the option value macros from OpenSSL. */
1578 if (!tls_openssl_options_parse(openssl_options
, &init_options
))
1579 return tls_error(US
"openssl_options parsing failed", host
, NULL
, errstr
);
1583 DEBUG(D_tls
) debug_printf("setting SSL CTX options: %#lx\n", init_options
);
1584 if (!(SSL_CTX_set_options(ctx
, init_options
)))
1585 return tls_error(string_sprintf(
1586 "SSL_CTX_set_option(%#lx)", init_options
), host
, NULL
, errstr
);
1589 DEBUG(D_tls
) debug_printf("no SSL CTX options to set\n");
1591 /* Disable session cache unconditionally */
1593 (void) SSL_CTX_set_session_cache_mode(ctx
, SSL_SESS_CACHE_OFF
);
1595 /* Initialize with DH parameters if supplied */
1596 /* Initialize ECDH temp key parameter selection */
1598 if ( !init_dh(ctx
, dhparam
, host
, errstr
)
1599 || !init_ecdh(ctx
, host
, errstr
)
1603 /* Set up certificate and key (and perhaps OCSP info) */
1605 if ((rc
= tls_expand_session_files(ctx
, cbinfo
, errstr
)) != OK
)
1608 /* If we need to handle SNI or OCSP, do so */
1610 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
1611 # ifndef DISABLE_OCSP
1612 if (!(cbinfo
->verify_stack
= sk_X509_new_null()))
1614 DEBUG(D_tls
) debug_printf("failed to create stack for stapling verify\n");
1619 if (host
== NULL
) /* server */
1621 # ifndef DISABLE_OCSP
1622 /* We check u_ocsp.server.file, not server.response, because we care about if
1623 the option exists, not what the current expansion might be, as SNI might
1624 change the certificate and OCSP file in use between now and the time the
1625 callback is invoked. */
1626 if (cbinfo
->u_ocsp
.server
.file
)
1628 SSL_CTX_set_tlsext_status_cb(ctx
, tls_server_stapling_cb
);
1629 SSL_CTX_set_tlsext_status_arg(ctx
, cbinfo
);
1632 /* We always do this, so that $tls_sni is available even if not used in
1634 SSL_CTX_set_tlsext_servername_callback(ctx
, tls_servername_cb
);
1635 SSL_CTX_set_tlsext_servername_arg(ctx
, cbinfo
);
1637 # ifndef DISABLE_OCSP
1639 if(ocsp_file
) /* wanting stapling */
1641 if (!(cbinfo
->u_ocsp
.client
.verify_store
= X509_STORE_new()))
1643 DEBUG(D_tls
) debug_printf("failed to create store for stapling verify\n");
1646 SSL_CTX_set_tlsext_status_cb(ctx
, tls_client_stapling_cb
);
1647 SSL_CTX_set_tlsext_status_arg(ctx
, cbinfo
);
1652 cbinfo
->verify_cert_hostnames
= NULL
;
1654 #ifdef EXIM_HAVE_EPHEM_RSA_KEX
1655 /* Set up the RSA callback */
1656 SSL_CTX_set_tmp_rsa_callback(ctx
, rsa_callback
);
1659 /* Finally, set the timeout, and we are done */
1661 SSL_CTX_set_timeout(ctx
, ssl_session_timeout
);
1662 DEBUG(D_tls
) debug_printf("Initialized TLS\n");
1673 /*************************************************
1674 * Get name of cipher in use *
1675 *************************************************/
1678 Argument: pointer to an SSL structure for the connection
1679 buffer to use for answer
1681 pointer to number of bits for cipher
1686 construct_cipher_name(SSL
*ssl
, uschar
*cipherbuf
, int bsize
, int *bits
)
1688 /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't
1689 yet reflect that. It should be a safe change anyway, even 0.9.8 versions have
1690 the accessor functions use const in the prototype. */
1691 const SSL_CIPHER
*c
;
1694 ver
= (const uschar
*)SSL_get_version(ssl
);
1696 c
= (const SSL_CIPHER
*) SSL_get_current_cipher(ssl
);
1697 SSL_CIPHER_get_bits(c
, bits
);
1699 string_format(cipherbuf
, bsize
, "%s:%s:%u", ver
,
1700 SSL_CIPHER_get_name(c
), *bits
);
1702 DEBUG(D_tls
) debug_printf("Cipher: %s\n", cipherbuf
);
1707 peer_cert(SSL
* ssl
, tls_support
* tlsp
, uschar
* peerdn
, unsigned bsize
)
1709 /*XXX we might consider a list-of-certs variable for the cert chain.
1710 SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support
1711 in list-handling functions, also consider the difference between the entire
1712 chain and the elements sent by the peer. */
1714 /* Will have already noted peercert on a verify fail; possibly not the leaf */
1715 if (!tlsp
->peercert
)
1716 tlsp
->peercert
= SSL_get_peer_certificate(ssl
);
1717 /* Beware anonymous ciphers which lead to server_cert being NULL */
1720 X509_NAME_oneline(X509_get_subject_name(tlsp
->peercert
), CS peerdn
, bsize
);
1721 peerdn
[bsize
-1] = '\0';
1722 tlsp
->peerdn
= peerdn
; /*XXX a static buffer... */
1725 tlsp
->peerdn
= NULL
;
1732 /*************************************************
1733 * Set up for verifying certificates *
1734 *************************************************/
1736 /* Load certs from file, return TRUE on success */
1739 chain_from_pem_file(const uschar
* file
, STACK_OF(X509
) * verify_stack
)
1744 if (!(bp
= BIO_new_file(CS file
, "r"))) return FALSE
;
1745 while ((x
= PEM_read_bio_X509(bp
, NULL
, 0, NULL
)))
1746 sk_X509_push(verify_stack
, x
);
1753 /* Called by both client and server startup
1756 sctx SSL_CTX* to initialise
1757 certs certs file or NULL
1758 crl CRL file or NULL
1759 host NULL in a server; the remote host in a client
1760 optional TRUE if called from a server for a host in tls_try_verify_hosts;
1761 otherwise passed as FALSE
1762 cert_vfy_cb Callback function for certificate verification
1763 errstr error string pointer
1765 Returns: OK/DEFER/FAIL
1769 setup_certs(SSL_CTX
*sctx
, uschar
*certs
, uschar
*crl
, host_item
*host
, BOOL optional
,
1770 int (*cert_vfy_cb
)(int, X509_STORE_CTX
*), uschar
** errstr
)
1772 uschar
*expcerts
, *expcrl
;
1774 if (!expand_check(certs
, US
"tls_verify_certificates", &expcerts
, errstr
))
1776 DEBUG(D_tls
) debug_printf("tls_verify_certificates: %s\n", expcerts
);
1778 if (expcerts
&& *expcerts
)
1780 /* Tell the library to use its compiled-in location for the system default
1781 CA bundle. Then add the ones specified in the config, if any. */
1783 if (!SSL_CTX_set_default_verify_paths(sctx
))
1784 return tls_error(US
"SSL_CTX_set_default_verify_paths", host
, NULL
, errstr
);
1786 if (Ustrcmp(expcerts
, "system") != 0)
1788 struct stat statbuf
;
1790 if (Ustat(expcerts
, &statbuf
) < 0)
1792 log_write(0, LOG_MAIN
|LOG_PANIC
,
1793 "failed to stat %s for certificates", expcerts
);
1799 if ((statbuf
.st_mode
& S_IFMT
) == S_IFDIR
)
1800 { file
= NULL
; dir
= expcerts
; }
1803 file
= expcerts
; dir
= NULL
;
1804 #ifndef DISABLE_OCSP
1805 /* In the server if we will be offering an OCSP proof, load chain from
1806 file for verifying the OCSP proof at load time. */
1809 && statbuf
.st_size
> 0
1810 && server_static_cbinfo
->u_ocsp
.server
.file
1811 && !chain_from_pem_file(file
, server_static_cbinfo
->verify_stack
)
1814 log_write(0, LOG_MAIN
|LOG_PANIC
,
1815 "failed to load cert chain from %s", file
);
1821 /* If a certificate file is empty, the next function fails with an
1822 unhelpful error message. If we skip it, we get the correct behaviour (no
1823 certificates are recognized, but the error message is still misleading (it
1824 says no certificate was supplied). But this is better. */
1826 if ( (!file
|| statbuf
.st_size
> 0)
1827 && !SSL_CTX_load_verify_locations(sctx
, CS file
, CS dir
))
1828 return tls_error(US
"SSL_CTX_load_verify_locations", host
, NULL
, errstr
);
1830 /* Load the list of CAs for which we will accept certs, for sending
1831 to the client. This is only for the one-file tls_verify_certificates
1833 If a list isn't loaded into the server, but
1834 some verify locations are set, the server end appears to make
1835 a wildcard request for client certs.
1836 Meanwhile, the client library as default behaviour *ignores* the list
1837 we send over the wire - see man SSL_CTX_set_client_cert_cb.
1838 Because of this, and that the dir variant is likely only used for
1839 the public-CA bundle (not for a private CA), not worth fixing.
1843 STACK_OF(X509_NAME
) * names
= SSL_load_client_CA_file(CS file
);
1845 DEBUG(D_tls
) debug_printf("Added %d certificate authorities.\n",
1846 sk_X509_NAME_num(names
));
1847 SSL_CTX_set_client_CA_list(sctx
, names
);
1852 /* Handle a certificate revocation list. */
1854 #if OPENSSL_VERSION_NUMBER > 0x00907000L
1856 /* This bit of code is now the version supplied by Lars Mainka. (I have
1857 merely reformatted it into the Exim code style.)
1859 "From here I changed the code to add support for multiple crl's
1860 in pem format in one file or to support hashed directory entries in
1861 pem format instead of a file. This method now uses the library function
1862 X509_STORE_load_locations to add the CRL location to the SSL context.
1863 OpenSSL will then handle the verify against CA certs and CRLs by
1864 itself in the verify callback." */
1866 if (!expand_check(crl
, US
"tls_crl", &expcrl
, errstr
)) return DEFER
;
1867 if (expcrl
&& *expcrl
)
1869 struct stat statbufcrl
;
1870 if (Ustat(expcrl
, &statbufcrl
) < 0)
1872 log_write(0, LOG_MAIN
|LOG_PANIC
,
1873 "failed to stat %s for certificates revocation lists", expcrl
);
1878 /* is it a file or directory? */
1880 X509_STORE
*cvstore
= SSL_CTX_get_cert_store(sctx
);
1881 if ((statbufcrl
.st_mode
& S_IFMT
) == S_IFDIR
)
1885 DEBUG(D_tls
) debug_printf("SSL CRL value is a directory %s\n", dir
);
1891 DEBUG(D_tls
) debug_printf("SSL CRL value is a file %s\n", file
);
1893 if (X509_STORE_load_locations(cvstore
, CS file
, CS dir
) == 0)
1894 return tls_error(US
"X509_STORE_load_locations", host
, NULL
, errstr
);
1896 /* setting the flags to check against the complete crl chain */
1898 X509_STORE_set_flags(cvstore
,
1899 X509_V_FLAG_CRL_CHECK
|X509_V_FLAG_CRL_CHECK_ALL
);
1903 #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
1905 /* If verification is optional, don't fail if no certificate */
1907 SSL_CTX_set_verify(sctx
,
1908 SSL_VERIFY_PEER
| (optional
? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT
),
1917 /*************************************************
1918 * Start a TLS session in a server *
1919 *************************************************/
1921 /* This is called when Exim is running as a server, after having received
1922 the STARTTLS command. It must respond to that command, and then negotiate
1926 require_ciphers allowed ciphers
1927 errstr pointer to error message
1929 Returns: OK on success
1930 DEFER for errors before the start of the negotiation
1931 FAIL for errors during the negotiation; the server can't
1936 tls_server_start(const uschar
* require_ciphers
, uschar
** errstr
)
1939 uschar
* expciphers
;
1940 tls_ext_ctx_cb
* cbinfo
;
1941 static uschar peerdn
[256];
1942 static uschar cipherbuf
[256];
1944 /* Check for previous activation */
1946 if (tls_in
.active
>= 0)
1948 tls_error(US
"STARTTLS received after TLS started", NULL
, US
"", errstr
);
1949 smtp_printf("554 Already in TLS\r\n", FALSE
);
1953 /* Initialize the SSL library. If it fails, it will already have logged
1956 rc
= tls_init(&server_ctx
, NULL
, tls_dhparam
, tls_certificate
, tls_privatekey
,
1957 #ifndef DISABLE_OCSP
1958 tls_ocsp_file
, /*XXX stack*/
1960 NULL
, &server_static_cbinfo
, errstr
);
1961 if (rc
!= OK
) return rc
;
1962 cbinfo
= server_static_cbinfo
;
1964 if (!expand_check(require_ciphers
, US
"tls_require_ciphers", &expciphers
, errstr
))
1967 /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
1968 were historically separated by underscores. So that I can use either form in my
1969 tests, and also for general convenience, we turn underscores into hyphens here.
1974 uschar
* s
= expciphers
;
1975 while (*s
!= 0) { if (*s
== '_') *s
= '-'; s
++; }
1976 DEBUG(D_tls
) debug_printf("required ciphers: %s\n", expciphers
);
1977 if (!SSL_CTX_set_cipher_list(server_ctx
, CS expciphers
))
1978 return tls_error(US
"SSL_CTX_set_cipher_list", NULL
, NULL
, errstr
);
1979 cbinfo
->server_cipher_list
= expciphers
;
1982 /* If this is a host for which certificate verification is mandatory or
1983 optional, set up appropriately. */
1985 tls_in
.certificate_verified
= FALSE
;
1986 #ifdef EXPERIMENTAL_DANE
1987 tls_in
.dane_verified
= FALSE
;
1989 server_verify_callback_called
= FALSE
;
1991 if (verify_check_host(&tls_verify_hosts
) == OK
)
1993 rc
= setup_certs(server_ctx
, tls_verify_certificates
, tls_crl
, NULL
,
1994 FALSE
, verify_callback_server
, errstr
);
1995 if (rc
!= OK
) return rc
;
1996 server_verify_optional
= FALSE
;
1998 else if (verify_check_host(&tls_try_verify_hosts
) == OK
)
2000 rc
= setup_certs(server_ctx
, tls_verify_certificates
, tls_crl
, NULL
,
2001 TRUE
, verify_callback_server
, errstr
);
2002 if (rc
!= OK
) return rc
;
2003 server_verify_optional
= TRUE
;
2006 /* Prepare for new connection */
2008 if (!(server_ssl
= SSL_new(server_ctx
)))
2009 return tls_error(US
"SSL_new", NULL
, NULL
, errstr
);
2011 /* Warning: we used to SSL_clear(ssl) here, it was removed.
2013 * With the SSL_clear(), we get strange interoperability bugs with
2014 * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in
2015 * OpenSSL itself, as a clear should not lead to inability to follow protocols.
2017 * The SSL_clear() call is to let an existing SSL* be reused, typically after
2018 * session shutdown. In this case, we have a brand new object and there's no
2019 * obvious reason to immediately clear it. I'm guessing that this was
2020 * originally added because of incomplete initialisation which the clear fixed,
2021 * in some historic release.
2024 /* Set context and tell client to go ahead, except in the case of TLS startup
2025 on connection, where outputting anything now upsets the clients and tends to
2026 make them disconnect. We need to have an explicit fflush() here, to force out
2027 the response. Other smtp_printf() calls do not need it, because in non-TLS
2028 mode, the fflush() happens when smtp_getc() is called. */
2030 SSL_set_session_id_context(server_ssl
, sid_ctx
, Ustrlen(sid_ctx
));
2031 if (!tls_in
.on_connect
)
2033 smtp_printf("220 TLS go ahead\r\n", FALSE
);
2037 /* Now negotiate the TLS session. We put our own timer on it, since it seems
2038 that the OpenSSL library doesn't. */
2040 SSL_set_wfd(server_ssl
, fileno(smtp_out
));
2041 SSL_set_rfd(server_ssl
, fileno(smtp_in
));
2042 SSL_set_accept_state(server_ssl
);
2044 DEBUG(D_tls
) debug_printf("Calling SSL_accept\n");
2046 sigalrm_seen
= FALSE
;
2047 if (smtp_receive_timeout
> 0) alarm(smtp_receive_timeout
);
2048 rc
= SSL_accept(server_ssl
);
2053 (void) tls_error(US
"SSL_accept", NULL
, sigalrm_seen
? US
"timed out" : NULL
, errstr
);
2057 DEBUG(D_tls
) debug_printf("SSL_accept was successful\n");
2059 /* TLS has been set up. Adjust the input functions to read via TLS,
2060 and initialize things. */
2062 peer_cert(server_ssl
, &tls_in
, peerdn
, sizeof(peerdn
));
2064 construct_cipher_name(server_ssl
, cipherbuf
, sizeof(cipherbuf
), &tls_in
.bits
);
2065 tls_in
.cipher
= cipherbuf
;
2070 if (SSL_get_shared_ciphers(server_ssl
, CS buf
, sizeof(buf
)) != NULL
)
2071 debug_printf("Shared ciphers: %s\n", buf
);
2074 /* Record the certificate we presented */
2076 X509
* crt
= SSL_get_certificate(server_ssl
);
2077 tls_in
.ourcert
= crt
? X509_dup(crt
) : NULL
;
2080 /* Only used by the server-side tls (tls_in), including tls_getc.
2081 Client-side (tls_out) reads (seem to?) go via
2082 smtp_read_response()/ip_recv().
2083 Hence no need to duplicate for _in and _out.
2085 ssl_xfer_buffer
= store_malloc(ssl_xfer_buffer_size
);
2086 ssl_xfer_buffer_lwm
= ssl_xfer_buffer_hwm
= 0;
2087 ssl_xfer_eof
= ssl_xfer_error
= 0;
2089 receive_getc
= tls_getc
;
2090 receive_getbuf
= tls_getbuf
;
2091 receive_get_cache
= tls_get_cache
;
2092 receive_ungetc
= tls_ungetc
;
2093 receive_feof
= tls_feof
;
2094 receive_ferror
= tls_ferror
;
2095 receive_smtp_buffered
= tls_smtp_buffered
;
2097 tls_in
.active
= fileno(smtp_out
);
2105 tls_client_basic_ctx_init(SSL_CTX
* ctx
,
2106 host_item
* host
, smtp_transport_options_block
* ob
, tls_ext_ctx_cb
* cbinfo
,
2110 /* stick to the old behaviour for compatibility if tls_verify_certificates is
2111 set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only
2112 the specified host patterns if one of them is defined */
2114 if ( ( !ob
->tls_verify_hosts
2115 && (!ob
->tls_try_verify_hosts
|| !*ob
->tls_try_verify_hosts
)
2117 || (verify_check_given_host(&ob
->tls_verify_hosts
, host
) == OK
)
2119 client_verify_optional
= FALSE
;
2120 else if (verify_check_given_host(&ob
->tls_try_verify_hosts
, host
) == OK
)
2121 client_verify_optional
= TRUE
;
2125 if ((rc
= setup_certs(ctx
, ob
->tls_verify_certificates
,
2126 ob
->tls_crl
, host
, client_verify_optional
, verify_callback_client
,
2130 if (verify_check_given_host(&ob
->tls_verify_cert_hostnames
, host
) == OK
)
2132 cbinfo
->verify_cert_hostnames
=
2134 string_domain_utf8_to_alabel(host
->name
, NULL
);
2138 DEBUG(D_tls
) debug_printf("Cert hostname to check: \"%s\"\n",
2139 cbinfo
->verify_cert_hostnames
);
2145 #ifdef EXPERIMENTAL_DANE
2147 dane_tlsa_load(SSL
* ssl
, host_item
* host
, dns_answer
* dnsa
, uschar
** errstr
)
2151 const char * hostnames
[2] = { CS host
->name
, NULL
};
2154 if (DANESSL_init(ssl
, NULL
, hostnames
) != 1)
2155 return tls_error(US
"hostnames load", host
, NULL
, errstr
);
2157 for (rr
= dns_next_rr(dnsa
, &dnss
, RESET_ANSWERS
);
2159 rr
= dns_next_rr(dnsa
, &dnss
, RESET_NEXT
)
2160 ) if (rr
->type
== T_TLSA
)
2162 const uschar
* p
= rr
->data
;
2163 uint8_t usage
, selector
, mtype
;
2164 const char * mdname
;
2168 /* Only DANE-TA(2) and DANE-EE(3) are supported */
2169 if (usage
!= 2 && usage
!= 3) continue;
2176 default: continue; /* Only match-types 0, 1, 2 are supported */
2177 case 0: mdname
= NULL
; break;
2178 case 1: mdname
= "sha256"; break;
2179 case 2: mdname
= "sha512"; break;
2183 switch (DANESSL_add_tlsa(ssl
, usage
, selector
, mdname
, p
, rr
->size
- 3))
2186 return tls_error(US
"tlsa load", host
, NULL
, errstr
);
2187 case 0: /* action not taken */
2191 tls_out
.tlsa_usage
|= 1<<usage
;
2197 log_write(0, LOG_MAIN
, "DANE error: No usable TLSA records");
2200 #endif /*EXPERIMENTAL_DANE*/
2204 /*************************************************
2205 * Start a TLS session in a client *
2206 *************************************************/
2208 /* Called from the smtp transport after STARTTLS has been accepted.
2211 fd the fd of the connection
2212 host connected host (for messages)
2213 addr the first address
2214 tb transport (always smtp)
2215 tlsa_dnsa tlsa lookup, if DANE, else null
2216 errstr error string pointer
2218 Returns: OK on success
2219 FAIL otherwise - note that tls_error() will not give DEFER
2220 because this is not a server
2224 tls_client_start(int fd
, host_item
*host
, address_item
*addr
,
2225 transport_instance
* tb
,
2226 #ifdef EXPERIMENTAL_DANE
2227 dns_answer
* tlsa_dnsa
,
2231 smtp_transport_options_block
* ob
=
2232 (smtp_transport_options_block
*)tb
->options_block
;
2233 static uschar peerdn
[256];
2234 uschar
* expciphers
;
2236 static uschar cipherbuf
[256];
2238 #ifndef DISABLE_OCSP
2239 BOOL request_ocsp
= FALSE
;
2240 BOOL require_ocsp
= FALSE
;
2243 #ifdef EXPERIMENTAL_DANE
2244 tls_out
.tlsa_usage
= 0;
2247 #ifndef DISABLE_OCSP
2249 # ifdef EXPERIMENTAL_DANE
2251 && ob
->hosts_request_ocsp
[0] == '*'
2252 && ob
->hosts_request_ocsp
[1] == '\0'
2255 /* Unchanged from default. Use a safer one under DANE */
2256 request_ocsp
= TRUE
;
2257 ob
->hosts_request_ocsp
= US
"${if or { {= {0}{$tls_out_tlsa_usage}} "
2258 " {= {4}{$tls_out_tlsa_usage}} } "
2264 verify_check_given_host(&ob
->hosts_require_ocsp
, host
) == OK
))
2265 request_ocsp
= TRUE
;
2267 # ifdef EXPERIMENTAL_DANE
2271 verify_check_given_host(&ob
->hosts_request_ocsp
, host
) == OK
;
2275 rc
= tls_init(&client_ctx
, host
, NULL
,
2276 ob
->tls_certificate
, ob
->tls_privatekey
,
2277 #ifndef DISABLE_OCSP
2278 (void *)(long)request_ocsp
,
2280 addr
, &client_static_cbinfo
, errstr
);
2281 if (rc
!= OK
) return rc
;
2283 tls_out
.certificate_verified
= FALSE
;
2284 client_verify_callback_called
= FALSE
;
2286 if (!expand_check(ob
->tls_require_ciphers
, US
"tls_require_ciphers",
2287 &expciphers
, errstr
))
2290 /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
2291 are separated by underscores. So that I can use either form in my tests, and
2292 also for general convenience, we turn underscores into hyphens here. */
2296 uschar
*s
= expciphers
;
2297 while (*s
) { if (*s
== '_') *s
= '-'; s
++; }
2298 DEBUG(D_tls
) debug_printf("required ciphers: %s\n", expciphers
);
2299 if (!SSL_CTX_set_cipher_list(client_ctx
, CS expciphers
))
2300 return tls_error(US
"SSL_CTX_set_cipher_list", host
, NULL
, errstr
);
2303 #ifdef EXPERIMENTAL_DANE
2306 SSL_CTX_set_verify(client_ctx
,
2307 SSL_VERIFY_PEER
| SSL_VERIFY_FAIL_IF_NO_PEER_CERT
,
2308 verify_callback_client_dane
);
2310 if (!DANESSL_library_init())
2311 return tls_error(US
"library init", host
, NULL
, errstr
);
2312 if (DANESSL_CTX_init(client_ctx
) <= 0)
2313 return tls_error(US
"context init", host
, NULL
, errstr
);
2319 if ((rc
= tls_client_basic_ctx_init(client_ctx
, host
, ob
,
2320 client_static_cbinfo
, errstr
)) != OK
)
2323 if ((client_ssl
= SSL_new(client_ctx
)) == NULL
)
2324 return tls_error(US
"SSL_new", host
, NULL
, errstr
);
2325 SSL_set_session_id_context(client_ssl
, sid_ctx
, Ustrlen(sid_ctx
));
2326 SSL_set_fd(client_ssl
, fd
);
2327 SSL_set_connect_state(client_ssl
);
2331 if (!expand_check(ob
->tls_sni
, US
"tls_sni", &tls_out
.sni
, errstr
))
2335 DEBUG(D_tls
) debug_printf("Setting TLS SNI forced to fail, not sending\n");
2337 else if (!Ustrlen(tls_out
.sni
))
2341 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
2342 DEBUG(D_tls
) debug_printf("Setting TLS SNI \"%s\"\n", tls_out
.sni
);
2343 SSL_set_tlsext_host_name(client_ssl
, tls_out
.sni
);
2345 log_write(0, LOG_MAIN
, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n",
2351 #ifdef EXPERIMENTAL_DANE
2353 if ((rc
= dane_tlsa_load(client_ssl
, host
, tlsa_dnsa
, errstr
)) != OK
)
2357 #ifndef DISABLE_OCSP
2358 /* Request certificate status at connection-time. If the server
2359 does OCSP stapling we will get the callback (set in tls_init()) */
2360 # ifdef EXPERIMENTAL_DANE
2364 if ( ((s
= ob
->hosts_require_ocsp
) && Ustrstr(s
, US
"tls_out_tlsa_usage"))
2365 || ((s
= ob
->hosts_request_ocsp
) && Ustrstr(s
, US
"tls_out_tlsa_usage"))
2367 { /* Re-eval now $tls_out_tlsa_usage is populated. If
2368 this means we avoid the OCSP request, we wasted the setup
2369 cost in tls_init(). */
2370 require_ocsp
= verify_check_given_host(&ob
->hosts_require_ocsp
, host
) == OK
;
2371 request_ocsp
= require_ocsp
2372 || verify_check_given_host(&ob
->hosts_request_ocsp
, host
) == OK
;
2379 SSL_set_tlsext_status_type(client_ssl
, TLSEXT_STATUSTYPE_ocsp
);
2380 client_static_cbinfo
->u_ocsp
.client
.verify_required
= require_ocsp
;
2381 tls_out
.ocsp
= OCSP_NOT_RESP
;
2385 #ifndef DISABLE_EVENT
2386 client_static_cbinfo
->event_action
= tb
->event_action
;
2389 /* There doesn't seem to be a built-in timeout on connection. */
2391 DEBUG(D_tls
) debug_printf("Calling SSL_connect\n");
2392 sigalrm_seen
= FALSE
;
2393 alarm(ob
->command_timeout
);
2394 rc
= SSL_connect(client_ssl
);
2397 #ifdef EXPERIMENTAL_DANE
2399 DANESSL_cleanup(client_ssl
);
2403 return tls_error(US
"SSL_connect", host
, sigalrm_seen
? US
"timed out" : NULL
,
2406 DEBUG(D_tls
) debug_printf("SSL_connect succeeded\n");
2408 peer_cert(client_ssl
, &tls_out
, peerdn
, sizeof(peerdn
));
2410 construct_cipher_name(client_ssl
, cipherbuf
, sizeof(cipherbuf
), &tls_out
.bits
);
2411 tls_out
.cipher
= cipherbuf
;
2413 /* Record the certificate we presented */
2415 X509
* crt
= SSL_get_certificate(client_ssl
);
2416 tls_out
.ourcert
= crt
? X509_dup(crt
) : NULL
;
2419 tls_out
.active
= fd
;
2428 tls_refill(unsigned lim
)
2433 DEBUG(D_tls
) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl
,
2434 ssl_xfer_buffer
, ssl_xfer_buffer_size
);
2436 if (smtp_receive_timeout
> 0) alarm(smtp_receive_timeout
);
2437 inbytes
= SSL_read(server_ssl
, CS ssl_xfer_buffer
,
2438 MIN(ssl_xfer_buffer_size
, lim
));
2439 error
= SSL_get_error(server_ssl
, inbytes
);
2442 /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
2443 closed down, not that the socket itself has been closed down. Revert to
2444 non-SSL handling. */
2446 if (error
== SSL_ERROR_ZERO_RETURN
)
2448 DEBUG(D_tls
) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2450 receive_getc
= smtp_getc
;
2451 receive_getbuf
= smtp_getbuf
;
2452 receive_get_cache
= smtp_get_cache
;
2453 receive_ungetc
= smtp_ungetc
;
2454 receive_feof
= smtp_feof
;
2455 receive_ferror
= smtp_ferror
;
2456 receive_smtp_buffered
= smtp_buffered
;
2458 SSL_free(server_ssl
);
2462 tls_in
.cipher
= NULL
;
2463 tls_in
.peerdn
= NULL
;
2469 /* Handle genuine errors */
2471 else if (error
== SSL_ERROR_SSL
)
2473 ERR_error_string(ERR_get_error(), ssl_errstring
);
2474 log_write(0, LOG_MAIN
, "TLS error (SSL_read): %s", ssl_errstring
);
2479 else if (error
!= SSL_ERROR_NONE
)
2481 DEBUG(D_tls
) debug_printf("Got SSL error %d\n", error
);
2486 #ifndef DISABLE_DKIM
2487 dkim_exim_verify_feed(ssl_xfer_buffer
, inbytes
);
2489 ssl_xfer_buffer_hwm
= inbytes
;
2490 ssl_xfer_buffer_lwm
= 0;
2495 /*************************************************
2496 * TLS version of getc *
2497 *************************************************/
2499 /* This gets the next byte from the TLS input buffer. If the buffer is empty,
2500 it refills the buffer via the SSL reading function.
2502 Arguments: lim Maximum amount to read/buffer
2503 Returns: the next character or EOF
2505 Only used by the server-side TLS.
2509 tls_getc(unsigned lim
)
2511 if (ssl_xfer_buffer_lwm
>= ssl_xfer_buffer_hwm
)
2512 if (!tls_refill(lim
))
2513 return ssl_xfer_error
? EOF
: smtp_getc(lim
);
2515 /* Something in the buffer; return next uschar */
2517 return ssl_xfer_buffer
[ssl_xfer_buffer_lwm
++];
2521 tls_getbuf(unsigned * len
)
2526 if (ssl_xfer_buffer_lwm
>= ssl_xfer_buffer_hwm
)
2527 if (!tls_refill(*len
))
2529 if (!ssl_xfer_error
) return smtp_getbuf(len
);
2534 if ((size
= ssl_xfer_buffer_hwm
- ssl_xfer_buffer_lwm
) > *len
)
2536 buf
= &ssl_xfer_buffer
[ssl_xfer_buffer_lwm
];
2537 ssl_xfer_buffer_lwm
+= size
;
2546 #ifndef DISABLE_DKIM
2547 int n
= ssl_xfer_buffer_hwm
- ssl_xfer_buffer_lwm
;
2549 dkim_exim_verify_feed(ssl_xfer_buffer
+ssl_xfer_buffer_lwm
, n
);
2555 tls_could_read(void)
2557 return ssl_xfer_buffer_lwm
< ssl_xfer_buffer_hwm
|| SSL_pending(server_ssl
) > 0;
2561 /*************************************************
2562 * Read bytes from TLS channel *
2563 *************************************************/
2570 Returns: the number of bytes read
2571 -1 after a failed read
2573 Only used by the client-side TLS.
2577 tls_read(BOOL is_server
, uschar
*buff
, size_t len
)
2579 SSL
*ssl
= is_server
? server_ssl
: client_ssl
;
2583 DEBUG(D_tls
) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl
,
2584 buff
, (unsigned int)len
);
2586 inbytes
= SSL_read(ssl
, CS buff
, len
);
2587 error
= SSL_get_error(ssl
, inbytes
);
2589 if (error
== SSL_ERROR_ZERO_RETURN
)
2591 DEBUG(D_tls
) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2594 else if (error
!= SSL_ERROR_NONE
)
2604 /*************************************************
2605 * Write bytes down TLS channel *
2606 *************************************************/
2610 is_server channel specifier
2613 more further data expected soon
2615 Returns: the number of bytes after a successful write,
2616 -1 after a failed write
2618 Used by both server-side and client-side TLS.
2622 tls_write(BOOL is_server
, const uschar
*buff
, size_t len
, BOOL more
)
2624 int outbytes
, error
, left
;
2625 SSL
*ssl
= is_server
? server_ssl
: client_ssl
;
2626 static gstring
* corked
= NULL
;
2628 DEBUG(D_tls
) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__
,
2629 buff
, (unsigned long)len
, more
? ", more" : "");
2631 /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when
2632 "more" is notified. This hack is only ok if small amounts are involved AND only
2633 one stream does it, in one context (i.e. no store reset). Currently it is used
2634 for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */
2636 if (is_server
&& (more
|| corked
))
2638 corked
= string_catn(corked
, buff
, len
);
2641 buff
= CUS corked
->s
;
2646 for (left
= len
; left
> 0;)
2648 DEBUG(D_tls
) debug_printf("SSL_write(SSL, %p, %d)\n", buff
, left
);
2649 outbytes
= SSL_write(ssl
, CS buff
, left
);
2650 error
= SSL_get_error(ssl
, outbytes
);
2651 DEBUG(D_tls
) debug_printf("outbytes=%d error=%d\n", outbytes
, error
);
2655 ERR_error_string(ERR_get_error(), ssl_errstring
);
2656 log_write(0, LOG_MAIN
, "TLS error (SSL_write): %s", ssl_errstring
);
2659 case SSL_ERROR_NONE
:
2664 case SSL_ERROR_ZERO_RETURN
:
2665 log_write(0, LOG_MAIN
, "SSL channel closed on write");
2668 case SSL_ERROR_SYSCALL
:
2669 log_write(0, LOG_MAIN
, "SSL_write: (from %s) syscall: %s",
2670 sender_fullhost
? sender_fullhost
: US
"<unknown>",
2675 log_write(0, LOG_MAIN
, "SSL_write error %d", error
);
2684 /*************************************************
2685 * Close down a TLS session *
2686 *************************************************/
2688 /* This is also called from within a delivery subprocess forked from the
2689 daemon, to shut down the TLS library, without actually doing a shutdown (which
2690 would tamper with the SSL session in the parent process).
2692 Arguments: TRUE if SSL_shutdown is to be called
2695 Used by both server-side and client-side TLS.
2699 tls_close(BOOL is_server
, BOOL shutdown
)
2701 SSL
**sslp
= is_server
? &server_ssl
: &client_ssl
;
2702 int *fdp
= is_server
? &tls_in
.active
: &tls_out
.active
;
2704 if (*fdp
< 0) return; /* TLS was not active */
2708 DEBUG(D_tls
) debug_printf("tls_close(): shutting down SSL\n");
2709 SSL_shutdown(*sslp
);
2721 /*************************************************
2722 * Let tls_require_ciphers be checked at startup *
2723 *************************************************/
2725 /* The tls_require_ciphers option, if set, must be something which the
2728 Returns: NULL on success, or error message
2732 tls_validate_require_cipher(void)
2735 uschar
*s
, *expciphers
, *err
;
2737 /* this duplicates from tls_init(), we need a better "init just global
2738 state, for no specific purpose" singleton function of our own */
2740 SSL_load_error_strings();
2741 OpenSSL_add_ssl_algorithms();
2742 #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
2743 /* SHA256 is becoming ever more popular. This makes sure it gets added to the
2744 list of available digests. */
2745 EVP_add_digest(EVP_sha256());
2748 if (!(tls_require_ciphers
&& *tls_require_ciphers
))
2751 if (!expand_check(tls_require_ciphers
, US
"tls_require_ciphers", &expciphers
,
2753 return US
"failed to expand tls_require_ciphers";
2755 if (!(expciphers
&& *expciphers
))
2758 /* normalisation ripped from above */
2760 while (*s
!= 0) { if (*s
== '_') *s
= '-'; s
++; }
2764 ctx
= SSL_CTX_new(SSLv23_server_method());
2767 ERR_error_string(ERR_get_error(), ssl_errstring
);
2768 return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring
);
2772 debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers
);
2774 if (!SSL_CTX_set_cipher_list(ctx
, CS expciphers
))
2776 ERR_error_string(ERR_get_error(), ssl_errstring
);
2777 err
= string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s",
2778 expciphers
, ssl_errstring
);
2789 /*************************************************
2790 * Report the library versions. *
2791 *************************************************/
2793 /* There have historically been some issues with binary compatibility in
2794 OpenSSL libraries; if Exim (like many other applications) is built against
2795 one version of OpenSSL but the run-time linker picks up another version,
2796 it can result in serious failures, including crashing with a SIGSEGV. So
2797 report the version found by the compiler and the run-time version.
2799 Note: some OS vendors backport security fixes without changing the version
2800 number/string, and the version date remains unchanged. The _build_ date
2801 will change, so we can more usefully assist with version diagnosis by also
2802 reporting the build date.
2804 Arguments: a FILE* to print the results to
2809 tls_version_report(FILE *f
)
2811 fprintf(f
, "Library version: OpenSSL: Compile: %s\n"
2814 OPENSSL_VERSION_TEXT
,
2815 SSLeay_version(SSLEAY_VERSION
),
2816 SSLeay_version(SSLEAY_BUILT_ON
));
2817 /* third line is 38 characters for the %s and the line is 73 chars long;
2818 the OpenSSL output includes a "built on: " prefix already. */
2824 /*************************************************
2825 * Random number generation *
2826 *************************************************/
2828 /* Pseudo-random number generation. The result is not expected to be
2829 cryptographically strong but not so weak that someone will shoot themselves
2830 in the foot using it as a nonce in input in some email header scheme or
2831 whatever weirdness they'll twist this into. The result should handle fork()
2832 and avoid repeating sequences. OpenSSL handles that for us.
2836 Returns a random number in range [0, max-1]
2840 vaguely_random_number(int max
)
2844 static pid_t pidlast
= 0;
2847 uschar smallbuf
[sizeof(r
)];
2853 if (pidnow
!= pidlast
)
2855 /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state
2856 is unique for each thread", this doesn't apparently apply across processes,
2857 so our own warning from vaguely_random_number_fallback() applies here too.
2858 Fix per PostgreSQL. */
2864 /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
2868 gettimeofday(&r
.tv
, NULL
);
2871 RAND_seed(US (&r
), sizeof(r
));
2873 /* We're after pseudo-random, not random; if we still don't have enough data
2874 in the internal PRNG then our options are limited. We could sleep and hope
2875 for entropy to come along (prayer technique) but if the system is so depleted
2876 in the first place then something is likely to just keep taking it. Instead,
2877 we'll just take whatever little bit of pseudo-random we can still manage to
2880 needed_len
= sizeof(r
);
2881 /* Don't take 8 times more entropy than needed if int is 8 octets and we were
2882 asked for a number less than 10. */
2883 for (r
= max
, i
= 0; r
; ++i
)
2889 #ifdef EXIM_HAVE_RAND_PSEUDO
2890 /* We do not care if crypto-strong */
2891 i
= RAND_pseudo_bytes(smallbuf
, needed_len
);
2893 i
= RAND_bytes(smallbuf
, needed_len
);
2899 debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
2900 return vaguely_random_number_fallback(max
);
2904 for (p
= smallbuf
; needed_len
; --needed_len
, ++p
)
2910 /* We don't particularly care about weighted results; if someone wants
2911 smooth distribution and cares enough then they should submit a patch then. */
2918 /*************************************************
2919 * OpenSSL option parse *
2920 *************************************************/
2922 /* Parse one option for tls_openssl_options_parse below
2925 name one option name
2926 value place to store a value for it
2927 Returns success or failure in parsing
2930 struct exim_openssl_option
{
2934 /* We could use a macro to expand, but we need the ifdef and not all the
2935 options document which version they were introduced in. Policylet: include
2936 all options unless explicitly for DTLS, let the administrator choose which
2939 This list is current as of:
2941 Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev
2943 static struct exim_openssl_option exim_openssl_options
[] = {
2944 /* KEEP SORTED ALPHABETICALLY! */
2946 { US
"all", SSL_OP_ALL
},
2948 #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
2949 { US
"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
},
2951 #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE
2952 { US
"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE
},
2954 #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
2955 { US
"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
},
2957 #ifdef SSL_OP_EPHEMERAL_RSA
2958 { US
"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA
},
2960 #ifdef SSL_OP_LEGACY_SERVER_CONNECT
2961 { US
"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT
},
2963 #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
2964 { US
"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
},
2966 #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG
2967 { US
"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG
},
2969 #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING
2970 { US
"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING
},
2972 #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG
2973 { US
"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG
},
2975 #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
2976 { US
"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
},
2978 #ifdef SSL_OP_NO_COMPRESSION
2979 { US
"no_compression", SSL_OP_NO_COMPRESSION
},
2981 #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
2982 { US
"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
},
2984 #ifdef SSL_OP_NO_SSLv2
2985 { US
"no_sslv2", SSL_OP_NO_SSLv2
},
2987 #ifdef SSL_OP_NO_SSLv3
2988 { US
"no_sslv3", SSL_OP_NO_SSLv3
},
2990 #ifdef SSL_OP_NO_TICKET
2991 { US
"no_ticket", SSL_OP_NO_TICKET
},
2993 #ifdef SSL_OP_NO_TLSv1
2994 { US
"no_tlsv1", SSL_OP_NO_TLSv1
},
2996 #ifdef SSL_OP_NO_TLSv1_1
2997 #if SSL_OP_NO_TLSv1_1 == 0x00000400L
2998 /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */
2999 #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring
3001 { US
"no_tlsv1_1", SSL_OP_NO_TLSv1_1
},
3004 #ifdef SSL_OP_NO_TLSv1_2
3005 { US
"no_tlsv1_2", SSL_OP_NO_TLSv1_2
},
3007 #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG
3008 { US
"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG
},
3010 #ifdef SSL_OP_SINGLE_DH_USE
3011 { US
"single_dh_use", SSL_OP_SINGLE_DH_USE
},
3013 #ifdef SSL_OP_SINGLE_ECDH_USE
3014 { US
"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE
},
3016 #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG
3017 { US
"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG
},
3019 #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
3020 { US
"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
},
3022 #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG
3023 { US
"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG
},
3025 #ifdef SSL_OP_TLS_D5_BUG
3026 { US
"tls_d5_bug", SSL_OP_TLS_D5_BUG
},
3028 #ifdef SSL_OP_TLS_ROLLBACK_BUG
3029 { US
"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG
},
3032 static int exim_openssl_options_size
=
3033 sizeof(exim_openssl_options
)/sizeof(struct exim_openssl_option
);
3037 tls_openssl_one_option_parse(uschar
*name
, long *value
)
3040 int last
= exim_openssl_options_size
;
3041 while (last
> first
)
3043 int middle
= (first
+ last
)/2;
3044 int c
= Ustrcmp(name
, exim_openssl_options
[middle
].name
);
3047 *value
= exim_openssl_options
[middle
].value
;
3061 /*************************************************
3062 * OpenSSL option parsing logic *
3063 *************************************************/
3065 /* OpenSSL has a number of compatibility options which an administrator might
3066 reasonably wish to set. Interpret a list similarly to decode_bits(), so that
3067 we look like log_selector.
3070 option_spec the administrator-supplied string of options
3071 results ptr to long storage for the options bitmap
3072 Returns success or failure
3076 tls_openssl_options_parse(uschar
*option_spec
, long *results
)
3081 BOOL adding
, item_parsed
;
3083 result
= SSL_OP_NO_TICKET
;
3084 /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
3085 * from default because it increases BEAST susceptibility. */
3086 #ifdef SSL_OP_NO_SSLv2
3087 result
|= SSL_OP_NO_SSLv2
;
3089 #ifdef SSL_OP_SINGLE_DH_USE
3090 result
|= SSL_OP_SINGLE_DH_USE
;
3099 for (s
=option_spec
; *s
!= '\0'; /**/)
3101 while (isspace(*s
)) ++s
;
3104 if (*s
!= '+' && *s
!= '-')
3106 DEBUG(D_tls
) debug_printf("malformed openssl option setting: "
3107 "+ or - expected but found \"%s\"\n", s
);
3110 adding
= *s
++ == '+';
3111 for (end
= s
; (*end
!= '\0') && !isspace(*end
); ++end
) /**/ ;
3114 item_parsed
= tls_openssl_one_option_parse(s
, &item
);
3118 DEBUG(D_tls
) debug_printf("openssl option setting unrecognised: \"%s\"\n", s
);
3121 DEBUG(D_tls
) debug_printf("openssl option, %s from %lx: %lx (%s)\n",
3122 adding
? "adding" : "removing", result
, item
, s
);
3136 /* End of tls-openssl.c */