uschar *server_cipher_list;
/* only passed down to tls_error: */
host_item *host;
- uschar * verify_cert_hostnames;
+ const uschar * verify_cert_hostnames;
#ifdef EXPERIMENTAL_EVENT
uschar * event_action;
#endif
{
X509 * current_cert= tmp_obj->data.x509;
X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name));
+ name[sizeof(name)-1] = '\0';
debug_printf(" %s\n", name);
}
}
*/
+#ifdef EXPERIMENTAL_EVENT
+static int
+verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn,
+ BOOL *calledp, const BOOL *optionalp, const uschar * what)
+{
+uschar * ev;
+uschar * yield;
+X509 * old_cert;
+
+ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
+if (ev)
+ {
+ old_cert = tlsp->peercert;
+ tlsp->peercert = X509_dup(cert);
+ /* NB we do not bother setting peerdn */
+ if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth))))
+ {
+ log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: "
+ "depth=%d cert=%s: %s",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
+ what, depth, dn, yield);
+ *calledp = TRUE;
+ if (!*optionalp)
+ {
+ if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */
+ return 1; /* reject (leaving peercert set) */
+ }
+ DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
+ "(host in tls_try_verify_hosts)\n");
+ }
+ X509_free(tlsp->peercert);
+ tlsp->peercert = old_cert;
+ }
+return 0;
+}
+#endif
+
/*************************************************
* Callback for verification *
*************************************************/
/* The SSL library does certificate verification if set up to do so. This
callback has the current yes/no state is in "state". If verification succeeded,
-we set up the tls_peerdn string. If verification failed, what happens depends
-on whether the client is required to present a verifiable certificate or not.
+we set the certificate-verified flag. If verification failed, what happens
+depends on whether the client is required to present a verifiable certificate
+or not.
If verification is optional, we change the state to yes, but still log the
verification error. For some reason (it really would help to have proper
documentation of OpenSSL), this callback function then gets called again, this
-time with state = 1. In fact, that's useful, because we can set up the peerdn
-value, but we must take care not to set the private verified flag on the second
-time through.
+time with state = 1. We must take care not to set the private verified flag on
+the second time through.
Note: this function is not called if the client fails to present a certificate
when asked. We get here only if a certificate has been received. Handling of
{
X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
int depth = X509_STORE_CTX_get_error_depth(x509ctx);
-static uschar txt[256];
-#ifdef EXPERIMENTAL_EVENT
-uschar * ev;
-uschar * yield;
-#endif
+uschar dn[256];
-X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt));
+X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
+dn[sizeof(dn)-1] = '\0';
if (state == 0)
{
- log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s",
+ log_write(0, LOG_MAIN, "[%s] SSL verify error: depth=%d error=%s cert=%s",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
depth,
X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)),
- txt);
+ dn);
*calledp = TRUE;
if (!*optionalp)
{
- tlsp->peercert = X509_dup(cert);
- return 0; /* reject */
+ if (!tlsp->peercert)
+ tlsp->peercert = X509_dup(cert); /* record failing cert */
+ return 0; /* reject */
}
DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
"tls_try_verify_hosts)\n");
else if (depth != 0)
{
- DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, txt);
+ DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn);
#ifndef DISABLE_OCSP
if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store)
{ /* client, wanting stapling */
}
#endif
#ifdef EXPERIMENTAL_EVENT
- ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
- if (ev)
- {
- tlsp->peercert = X509_dup(cert);
- if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth))))
- {
- log_write(0, LOG_MAIN, "SSL verify denied by event-action: "
- "depth=%d cert=%s: %s", depth, txt, yield);
- *calledp = TRUE;
- if (!*optionalp)
- return 0; /* reject */
- DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
- "(host in tls_try_verify_hosts)\n");
- }
- X509_free(tlsp->peercert);
- tlsp->peercert = NULL;
- }
+ if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
+ return 0; /* reject, with peercert set */
#endif
}
else
{
- uschar * verify_cert_hostnames;
-
- tlsp->peerdn = txt;
- tlsp->peercert = X509_dup(cert);
+ const uschar * verify_cert_hostnames;
if ( tlsp == &tls_out
&& ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames)))
/* client, wanting hostname check */
-
-# if EXIM_HAVE_OPENSSL_CHECKHOST
-# ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
-# define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
-# endif
-# ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
-# define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
-# endif
{
+
+#ifdef EXIM_HAVE_OPENSSL_CHECKHOST
+# ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
+# define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
+# endif
+# ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
+# define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
+# endif
int sep = 0;
- uschar * list = verify_cert_hostnames;
+ const uschar * list = verify_cert_hostnames;
uschar * name;
int rc;
while ((name = string_nextinlist(&list, &sep, NULL, 0)))
if ((rc = X509_check_host(cert, name, 0,
X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
- | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS)))
+ | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS,
+ NULL)))
{
if (rc < 0)
{
- log_write(0, LOG_MAIN, "SSL verify error: internal error\n");
+ log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address);
name = NULL;
}
break;
}
if (!name)
- {
- log_write(0, LOG_MAIN,
- "SSL verify error: certificate name mismatch: \"%s\"\n", txt);
- *calledp = TRUE;
- if (!*optionalp)
- return 0; /* reject */
- DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
- "tls_try_verify_hosts)\n");
- }
- }
-# else
+#else
if (!tls_is_name_for_cert(verify_cert_hostnames, cert))
+#endif
{
log_write(0, LOG_MAIN,
- "SSL verify error: certificate name mismatch: \"%s\"\n", txt);
+ "[%s] SSL verify error: certificate name mismatch: \"%s\"",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
+ dn);
*calledp = TRUE;
if (!*optionalp)
- return 0; /* reject */
+ {
+ if (!tlsp->peercert)
+ tlsp->peercert = X509_dup(cert); /* record failing cert */
+ return 0; /* reject */
+ }
DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
"tls_try_verify_hosts)\n");
}
-# endif
+ }
#ifdef EXPERIMENTAL_EVENT
- ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
- if (ev)
- if ((yield = event_raise(ev, US"tls:cert", US"0")))
- {
- log_write(0, LOG_MAIN, "SSL verify denied by event-action: "
- "depth=0 cert=%s: %s", txt, yield);
- *calledp = TRUE;
- if (!*optionalp)
- return 0; /* reject */
- DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
- "(host in tls_try_verify_hosts)\n");
- }
+ if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
+ return 0; /* reject, with peercert set */
#endif
DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n",
- *calledp ? "" : " authenticated", txt);
+ *calledp ? "" : " authenticated", dn);
if (!*calledp) tlsp->certificate_verified = TRUE;
*calledp = TRUE;
}
verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx)
{
X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
-static uschar txt[256];
+uschar dn[256];
#ifdef EXPERIMENTAL_EVENT
int depth = X509_STORE_CTX_get_error_depth(x509ctx);
-uschar * yield;
+BOOL dummy_called, optional = FALSE;
#endif
-X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt));
+X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
+dn[sizeof(dn)-1] = '\0';
-DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", txt);
-tls_out.peerdn = txt;
-tls_out.peercert = X509_dup(cert);
+DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", dn);
#ifdef EXPERIMENTAL_EVENT
- if (client_static_cbinfo->event_action)
- {
- if ((yield = event_raise(client_static_cbinfo->event_action,
- US"tls:cert", string_sprintf("%d", depth))))
- {
- log_write(0, LOG_MAIN, "DANE verify denied by event-action: "
- "depth=%d cert=%s: %s", depth, txt, yield);
- tls_out.certificate_verified = FALSE;
- return 0; /* reject */
- }
- if (depth != 0)
- {
- X509_free(tls_out.peercert);
- tls_out.peercert = NULL;
- }
- }
+ if (verify_event(&tls_out, cert, depth, dn,
+ &dummy_called, &optional, US"DANE"))
+ return 0; /* reject, with peercert set */
#endif
if (state == 1)
/* If dhparam is set, expand it, and load up the parameters for DH encryption.
Arguments:
+ sctx The current SSL CTX (inbound or outbound)
dhparam DH parameter file or fixed parameter identity string
host connected host, if client; NULL if server
+/*************************************************
+* Initialize for ECDH *
+*************************************************/
+
+/* Load parameters for ECDH encryption.
+
+For now, we stick to NIST P-256 because: it's simple and easy to configure;
+it avoids any patent issues that might bite redistributors; despite events in
+the news and concerns over curve choices, we're not cryptographers, we're not
+pretending to be, and this is "good enough" to be better than no support,
+protecting against most adversaries. Given another year or two, there might
+be sufficient clarity about a "right" way forward to let us make an informed
+decision, instead of a knee-jerk reaction.
+
+Longer-term, we should look at supporting both various named curves and
+external files generated with "openssl ecparam", much as we do for init_dh().
+We should also support "none" as a value, to explicitly avoid initialisation.
+
+Patches welcome.
+
+Arguments:
+ sctx The current SSL CTX (inbound or outbound)
+ host connected host, if client; NULL if server
+
+Returns: TRUE if OK (nothing to set up, or setup worked)
+*/
+
+static BOOL
+init_ecdh(SSL_CTX *sctx, host_item *host)
+{
+if (host) /* No ECDH setup for clients, only for servers */
+ return TRUE;
+
+#ifndef SSL_CTX_set_tmp_ecdh
+/* No elliptic curve API in OpenSSL, skip it */
+DEBUG(D_tls)
+ debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
+return TRUE;
+#else
+# ifndef NID_X9_62_prime256v1
+/* For now, stick to NIST P-256 to get "something" running.
+If that's not available, bail */
+DEBUG(D_tls)
+ debug_printf("NIST P-256 EC curve not available, skipping ECDH setup\n");
+return TRUE;
+# else
+ {
+ EC_KEY * ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
+ BOOL rv;
+
+ /* The "tmp" in the name here refers to setting a tempoary key
+ not to the stability of the interface. */
+
+ if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) != 0))
+ {
+ DEBUG(D_tls) debug_printf("ECDH: enable NIST P-256 curve\n");
+ }
+ else
+ tls_error(US"Error enabling NIST P-256 curve", host, NULL);
+ EC_KEY_free(ecdh);
+ return rv;
+ }
+# endif
+#endif
+}
+
+
+
+
#ifndef DISABLE_OCSP
/*************************************************
* Load OCSP information into state *
SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
+
+if ( !init_dh(server_sni, cbinfo->dhparam, NULL)
+ || !init_ecdh(server_sni, NULL)
+ )
+ return SSL_TLSEXT_ERR_NOACK;
+
if (cbinfo->server_cipher_list)
SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list);
#ifndef DISABLE_OCSP
/* do this after setup_certs, because this can require the certs for verifying
OCSP information. */
-rc = tls_expand_session_files(server_sni, cbinfo);
-if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
-
-if (!init_dh(server_sni, cbinfo->dhparam, NULL))
+if ((rc = tls_expand_session_files(server_sni, cbinfo)) != OK)
return SSL_TLSEXT_ERR_NOACK;
DEBUG(D_tls) debug_printf("Switching SSL context.\n");
/* Set up the information callback, which outputs if debugging is at a suitable
level. */
-SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback);
+DEBUG(D_tls) SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback);
/* Automatically re-try reads/writes after renegotiation. */
(void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY);
/* Initialize with DH parameters if supplied */
-if (!init_dh(*ctxp, dhparam, host)) return DEFER;
+if ( !init_dh(*ctxp, dhparam, host)
+ || !init_ecdh(*ctxp, host)
+ )
+ return DEFER;
/* Set up certificate and key (and perhaps OCSP info) */
}
+static void
+peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize)
+{
+/*XXX we might consider a list-of-certs variable for the cert chain.
+SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support
+in list-handling functions, also consider the difference between the entire
+chain and the elements sent by the peer. */
+
+/* Will have already noted peercert on a verify fail; possibly not the leaf */
+if (!tlsp->peercert)
+ tlsp->peercert = SSL_get_peer_certificate(ssl);
+/* Beware anonymous ciphers which lead to server_cert being NULL */
+if (tlsp->peercert)
+ {
+ X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize);
+ peerdn[bsize-1] = '\0';
+ tlsp->peerdn = peerdn; /*XXX a static buffer... */
+ }
+else
+ tlsp->peerdn = NULL;
+}
+
+
int rc;
uschar *expciphers;
tls_ext_ctx_cb *cbinfo;
+static uschar peerdn[256];
static uschar cipherbuf[256];
/* Check for previous activation */
/* TLS has been set up. Adjust the input functions to read via TLS,
and initialize things. */
+peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn));
+
construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits);
tls_in.cipher = cipherbuf;
if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
{
- cbinfo->verify_cert_hostnames = host->name;
+ cbinfo->verify_cert_hostnames =
+#ifdef EXPERIMENTAL_INTERNATIONAL
+ string_domain_utf8_to_alabel(host->name, NULL);
+#else
+ host->name;
+#endif
DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
cbinfo->verify_cert_hostnames);
}
return OK;
log_write(0, LOG_MAIN, "DANE error: No usable TLSA records");
-return FAIL;
+return DEFER;
}
#endif /*EXPERIMENTAL_DANE*/
{
smtp_transport_options_block * ob =
(smtp_transport_options_block *)tb->options_block;
-static uschar txt[256];
+static uschar peerdn[256];
uschar * expciphers;
-X509 * server_cert;
int rc;
static uschar cipherbuf[256];
DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
-/* Beware anonymous ciphers which lead to server_cert being NULL */
-/*XXX server_cert is never freed... use X509_free() */
-server_cert = SSL_get_peer_certificate (client_ssl);
-if (server_cert)
- {
- tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert),
- CS txt, sizeof(txt));
- tls_out.peerdn = txt; /*XXX a static buffer... */
- }
-else
- tls_out.peerdn = NULL;
+peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn));
construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits);
tls_out.cipher = cipherbuf;
projects / exim.git / blobdiff