* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2014 */
+/* Copyright (c) University of Cambridge 1995 - 2015 */
/* See the file NOTICE for conditions of use and distribution. */
/* Copyright (c) Phil Pennock 2012 */
#if GNUTLS_VERSION_NUMBER >= 0x020c00
# include <gnutls/pkcs11.h>
#endif
-#ifdef EXPERIMENTAL_OCSP
+#if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP)
+# warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile"
+# define DISABLE_OCSP
+#endif
+#if GNUTLS_VERSION_NUMBER < 0x020a00 && defined(EXPERIMENTAL_EVENT)
+# warning "GnuTLS library version too old; tls:cert event unsupported"
+# undef EXPERIMENTAL_EVENT
+#endif
+#if GNUTLS_VERSION_NUMBER >= 0x030306
+# define SUPPORT_CA_DIR
+#else
+# undef SUPPORT_CA_DIR
+#endif
+#if GNUTLS_VERSION_NUMBER >= 0x030314
+# define SUPPORT_SYSDEFAULT_CABUNDLE
+#endif
+
+#ifndef DISABLE_OCSP
# include <gnutls/ocsp.h>
#endif
/* Values for verify_requirement */
enum peer_verify_requirement
- { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED
-#ifdef EXPERIMENTAL_CERTNAMES
- ,VERIFY_WITHHOST
-#endif
- };
+ { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED };
/* This holds most state for server or client; with this, we can set up an
outbound TLS-enabled connection in an ACL callout, while not stomping all
uschar *exp_tls_certificate;
uschar *exp_tls_privatekey;
- uschar *exp_tls_sni;
uschar *exp_tls_verify_certificates;
uschar *exp_tls_crl;
uschar *exp_tls_require_ciphers;
uschar *exp_tls_ocsp_file;
-#ifdef EXPERIMENTAL_CERTNAMES
- uschar *exp_tls_verify_cert_hostnames;
+ const uschar *exp_tls_verify_cert_hostnames;
+#ifdef EXPERIMENTAL_EVENT
+ uschar *event_action;
#endif
tls_support *tlsp; /* set in tls_init() */
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL,
-#ifdef EXPERIMENTAL_CERTNAMES
+ NULL,
+#ifdef EXPERIMENTAL_EVENT
NULL,
#endif
NULL,
single-threaded to keep from processing data on an inbound TLS connection while
talking to another TLS connection for an outbound check. This does mean that
there's no way for heart-beats to be responded to, for the duration of the
-second connection. */
+second connection.
+XXX But see gnutls_session_get_ptr()
+*/
static exim_gnutls_state_st state_server, state_client;
the library logging; a value less than 0 disables the calls to set up logging
callbacks. */
#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL
-#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1
+# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1
#endif
#ifndef EXIM_CLIENT_DH_MIN_BITS
-#define EXIM_CLIENT_DH_MIN_BITS 1024
+# define EXIM_CLIENT_DH_MIN_BITS 1024
#endif
/* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we
can ask for a bit-strength. Without that, we stick to the constant we had
before, for now. */
#ifndef EXIM_SERVER_DH_BITS_PRE2_12
-#define EXIM_SERVER_DH_BITS_PRE2_12 1024
+# define EXIM_SERVER_DH_BITS_PRE2_12 1024
#endif
#define exim_gnutls_err_check(Label) do { \
static int exim_sni_handling_cb(gnutls_session_t session);
-#ifdef EXPERIMENTAL_OCSP
+#ifndef DISABLE_OCSP
static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr,
gnutls_datum_t * ocsp_response);
#endif
{
if (host)
{
- log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s",
+ log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s)%s%s",
host->name, host->address, prefix, msg ? ": " : "", msg ? msg : "");
return FAIL;
}
uschar *conn_info = smtp_get_connection_info();
if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
conn_info += 5;
+ /* I'd like to get separated H= here, but too hard for now */
log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s",
conn_info, prefix, msg ? ": " : "", msg ? msg : "");
return DEFER;
/* Set the OCSP stapling server info */
-#ifdef EXPERIMENTAL_OCSP
+#ifndef DISABLE_OCSP
if ( !host /* server */
&& tls_ocsp_file
)
gnutls_certificate_set_ocsp_status_request_function(state->x509_cred,
server_ocsp_stapling_cb, state->exp_tls_ocsp_file);
- DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file);
+ DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file);
}
#endif
{
if (!expand_check_tlsvar(tls_verify_certificates))
return DEFER;
+#ifndef SUPPORT_SYSDEFAULT_CABUNDLE
+ if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0)
+ state->exp_tls_verify_certificates = NULL;
+#endif
if (state->tls_crl && *state->tls_crl)
if (!expand_check_tlsvar(tls_crl))
return DEFER;
return OK;
}
-if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0)
+#ifdef SUPPORT_SYSDEFAULT_CABUNDLE
+if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0)
+ cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred);
+else
+#endif
{
- log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s "
- "(tls_verify_certificates): %s", state->exp_tls_verify_certificates,
- strerror(errno));
- return DEFER;
- }
+ if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s "
+ "(tls_verify_certificates): %s", state->exp_tls_verify_certificates,
+ strerror(errno));
+ return DEFER;
+ }
-/* The test suite passes in /dev/null; we could check for that path explicitly,
-but who knows if someone has some weird FIFO which always dumps some certs, or
-other weirdness. The thing we really want to check is that it's not a
-directory, since while OpenSSL supports that, GnuTLS does not.
-So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */
-if (S_ISDIR(statbuf.st_mode))
- {
- DEBUG(D_tls)
- debug_printf("verify certificates path is a dir: \"%s\"\n",
- state->exp_tls_verify_certificates);
- log_write(0, LOG_MAIN|LOG_PANIC,
- "tls_verify_certificates \"%s\" is a directory",
- state->exp_tls_verify_certificates);
- return DEFER;
- }
+#ifndef SUPPORT_CA_DIR
+ /* The test suite passes in /dev/null; we could check for that path explicitly,
+ but who knows if someone has some weird FIFO which always dumps some certs, or
+ other weirdness. The thing we really want to check is that it's not a
+ directory, since while OpenSSL supports that, GnuTLS does not.
+ So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */
+ if (S_ISDIR(statbuf.st_mode))
+ {
+ DEBUG(D_tls)
+ debug_printf("verify certificates path is a dir: \"%s\"\n",
+ state->exp_tls_verify_certificates);
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "tls_verify_certificates \"%s\" is a directory",
+ state->exp_tls_verify_certificates);
+ return DEFER;
+ }
+#endif
-DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n",
- state->exp_tls_verify_certificates, statbuf.st_size);
+ DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n",
+ state->exp_tls_verify_certificates, statbuf.st_size);
-if (statbuf.st_size == 0)
- {
- DEBUG(D_tls)
- debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
- return OK;
+ if (statbuf.st_size == 0)
+ {
+ DEBUG(D_tls)
+ debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
+ return OK;
+ }
+
+ cert_count =
+
+#ifdef SUPPORT_CA_DIR
+ (statbuf.st_mode & S_IFMT) == S_IFDIR
+ ?
+ gnutls_certificate_set_x509_trust_dir(state->x509_cred,
+ CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM)
+ :
+#endif
+ gnutls_certificate_set_x509_trust_file(state->x509_cred,
+ CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM);
}
-cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred,
- CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM);
if (cert_count < 0)
{
rc = cert_count;
- exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file");
+ exim_gnutls_err_check(US"setting certificate trust");
}
DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count);
/* set SNI in client, only */
if (host)
{
- if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni))
+ if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni))
return DEFER;
- if (state->exp_tls_sni && *state->exp_tls_sni)
+ if (state->tlsp->sni && *state->tlsp->sni)
{
DEBUG(D_tls)
- debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni);
- sz = Ustrlen(state->exp_tls_sni);
+ debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni);
+ sz = Ustrlen(state->tlsp->sni);
rc = gnutls_server_name_set(state->session,
- GNUTLS_NAME_DNS, state->exp_tls_sni, sz);
+ GNUTLS_NAME_DNS, state->tlsp->sni, sz);
exim_gnutls_err_check(US"gnutls_server_name_set");
}
}
else
{
-#ifdef EXPERIMENTAL_CERTNAMES
- if (state->verify_requirement == VERIFY_WITHHOST)
+ if (state->exp_tls_verify_cert_hostnames)
{
int sep = 0;
- uschar * list = state->exp_tls_verify_cert_hostnames;
+ const uschar * list = state->exp_tls_verify_cert_hostnames;
uschar * name;
while (name = string_nextinlist(&list, &sep, NULL, 0))
if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name))
{
DEBUG(D_tls)
debug_printf("TLS certificate verification failed: cert name mismatch\n");
- gnutls_alert_send(state->session,
- GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
- return FALSE;
+ if (state->verify_requirement >= VERIFY_REQUIRED)
+ {
+ gnutls_alert_send(state->session,
+ GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
+ return FALSE;
+ }
+ return TRUE;
}
}
-#endif
state->peer_cert_verified = TRUE;
DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n",
state->peerdn ? state->peerdn : US"<unset>");
-#ifdef EXPERIMENTAL_OCSP
+#ifndef DISABLE_OCSP
static int
server_ocsp_stapling_cb(gnutls_session_t session, void * ptr,
#endif
+#ifdef EXPERIMENTAL_EVENT
+/*
+We use this callback to get observability and detail-level control
+for an exim TLS connection (either direction), raising a tls:cert event
+for each cert in the chain presented by the peer. Any event
+can deny verification.
+
+Return 0 for the handshake to continue or non-zero to terminate.
+*/
+
+static int
+verify_cb(gnutls_session_t session)
+{
+const gnutls_datum * cert_list;
+unsigned int cert_list_size = 0;
+gnutls_x509_crt_t crt;
+int rc;
+uschar * yield;
+exim_gnutls_state_st * state = gnutls_session_get_ptr(session);
+
+cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
+if (cert_list)
+ while (cert_list_size--)
+ {
+ rc = import_cert(&cert_list[cert_list_size], &crt);
+ if (rc != GNUTLS_E_SUCCESS)
+ {
+ DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n",
+ cert_list_size, gnutls_strerror(rc));
+ break;
+ }
+
+ state->tlsp->peercert = crt;
+ if ((yield = event_raise(state->event_action,
+ US"tls:cert", string_sprintf("%d", cert_list_size))))
+ {
+ log_write(0, LOG_MAIN,
+ "SSL verify denied by event-action: depth=%d: %s",
+ cert_list_size, yield);
+ return 1; /* reject */
+ }
+ state->tlsp->peercert = NULL;
+ }
+
+return 0;
+}
+
+#endif
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE);
}
+#ifdef EXPERIMENTAL_EVENT
+if (event_action)
+ {
+ state->event_action = event_action;
+ gnutls_session_set_ptr(state->session, state);
+ gnutls_certificate_set_verify_function(state->x509_cred, verify_cb);
+ }
+#endif
+
/* Register SNI handling; always, even if not in tls_certificate, so that the
expansion variable $tls_sni is always available. */
+static void
+tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state,
+ smtp_transport_options_block * ob)
+{
+if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
+ {
+ state->exp_tls_verify_cert_hostnames =
+#ifdef EXPERIMENTAL_INTERNATIONAL
+ string_domain_utf8_to_alabel(host->name, NULL);
+#else
+ host->name;
+#endif
+ DEBUG(D_tls)
+ debug_printf("TLS: server cert verification includes hostname: \"%s\".\n",
+ state->exp_tls_verify_cert_hostnames);
+ }
+}
+
+
/*************************************************
* Start a TLS session in a client *
*************************************************/
fd the fd of the connection
host connected host (for messages)
addr the first address (not used)
- ob smtp transport options
+ tb transport (always smtp)
Returns: OK/DEFER/FAIL (because using common functions),
but for a client, DEFER and FAIL have the same meaning
int
tls_client_start(int fd, host_item *host,
address_item *addr ARG_UNUSED,
- void *v_ob)
+ transport_instance *tb
+#ifdef EXPERIMENTAL_DANE
+ , dne_answer * unused_tlsa_dnsa
+#endif
+ )
{
-smtp_transport_options_block *ob = v_ob;
+smtp_transport_options_block *ob =
+ (smtp_transport_options_block *)tb->options_block;
int rc;
const char *error;
exim_gnutls_state_st *state = NULL;
-#ifdef EXPERIMENTAL_OCSP
-BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp,
- NULL, host->name, host->address, NULL) == OK;
+#ifndef DISABLE_OCSP
+BOOL require_ocsp =
+ verify_check_given_host(&ob->hosts_require_ocsp, host) == OK;
BOOL request_ocsp = require_ocsp ? TRUE
- : verify_check_this_host(&ob->hosts_request_ocsp,
- NULL, host->name, host->address, NULL) == OK;
+ : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK;
#endif
DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd);
set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only
the specified host patterns if one of them is defined */
-if (( state->exp_tls_verify_certificates
- && !ob->tls_verify_hosts
- && !ob->tls_try_verify_hosts
- )
- ||
- verify_check_host(&ob->tls_verify_hosts) == OK
+if ( ( state->exp_tls_verify_certificates
+ && !ob->tls_verify_hosts
+ && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts)
+ )
+ || verify_check_given_host(&ob->tls_verify_hosts, host) == OK
)
{
-#ifdef EXPERIMENTAL_CERTNAMES
- if (ob->tls_verify_cert_hostnames)
- {
- DEBUG(D_tls)
- debug_printf("TLS: server cert incl. hostname verification required.\n");
- state->verify_requirement = VERIFY_WITHHOST;
- if (!expand_check(ob->tls_verify_cert_hostnames,
- US"tls_verify_cert_hostnames",
- &state->exp_tls_verify_cert_hostnames))
- return FAIL;
- if (state->exp_tls_verify_cert_hostnames)
- DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
- state->exp_tls_verify_cert_hostnames);
- }
- else
-#endif
- {
- DEBUG(D_tls)
- debug_printf("TLS: server certificate verification required.\n");
- state->verify_requirement = VERIFY_REQUIRED;
- }
+ tls_client_setup_hostname_checks(host, state, ob);
+ DEBUG(D_tls)
+ debug_printf("TLS: server certificate verification required.\n");
+ state->verify_requirement = VERIFY_REQUIRED;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
}
-else if (verify_check_host(&ob->tls_try_verify_hosts) == OK)
+else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK)
{
+ tls_client_setup_hostname_checks(host, state, ob);
DEBUG(D_tls)
debug_printf("TLS: server certificate verification optional.\n");
state->verify_requirement = VERIFY_OPTIONAL;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE);
}
-#ifdef EXPERIMENTAL_OCSP /* since GnuTLS 3.1.3 */
+#ifndef DISABLE_OCSP
+ /* supported since GnuTLS 3.1.3 */
if (request_ocsp)
{
DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n");
}
#endif
+#ifdef EXPERIMENTAL_EVENT
+if (tb->event_action)
+ {
+ state->event_action = tb->event_action;
+ gnutls_session_set_ptr(state->session, state);
+ gnutls_certificate_set_verify_function(state->x509_cred, verify_cb);
+ }
+#endif
+
gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd);
state->fd_in = fd;
state->fd_out = fd;
!verify_certificate(state, &error))
return tls_error(US"certificate verification failed", error, state->host);
-#ifdef EXPERIMENTAL_OCSP
+#ifndef DISABLE_OCSP
if (require_ocsp)
{
DEBUG(D_tls)
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