#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_TPDA)
+# warning "GnuTLS library version too old; TPDA tls:cert event unsupported"
+# undef EXPERIMENTAL_TPDA
+#endif
+
+#ifndef DISABLE_OCSP
# include <gnutls/ocsp.h>
#endif
/* Values for verify_requirement */
-enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED };
+enum peer_verify_requirement
+ { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED
+#ifdef EXPERIMENTAL_CERTNAMES
+ ,VERIFY_WITHHOST
+#endif
+ };
/* 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
const uschar *tls_verify_certificates;
const uschar *tls_crl;
const uschar *tls_require_ciphers;
+
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;
+#endif
+#ifdef EXPERIMENTAL_TPDA
+ 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,
+#endif
+#ifdef EXPERIMENTAL_TPDA
+ NULL,
+#endif
NULL,
NULL, 0, 0, 0, 0,
};
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 { \
#define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname)
#if GNUTLS_VERSION_NUMBER >= 0x020c00
-#define HAVE_GNUTLS_SESSION_CHANNEL_BINDING
-#define HAVE_GNUTLS_SEC_PARAM_CONSTANTS
-#define HAVE_GNUTLS_RND
+# define HAVE_GNUTLS_SESSION_CHANNEL_BINDING
+# define HAVE_GNUTLS_SEC_PARAM_CONSTANTS
+# define HAVE_GNUTLS_RND
/* The security fix we provide with the gnutls_allow_auto_pkcs11 option
* (4.82 PP/09) introduces a compatibility regression. The symbol simply
* isn't available sometimes, so this needs to become a conditional
* compilation; the sanest way to deal with this being a problem on
* older OSes is to block it in the Local/Makefile with this compiler
* definition */
-#ifndef AVOID_GNUTLS_PKCS11
-#define HAVE_GNUTLS_PKCS11
-#endif /* AVOID_GNUTLS_PKCS11 */
+# ifndef AVOID_GNUTLS_PKCS11
+# define HAVE_GNUTLS_PKCS11
+# endif /* AVOID_GNUTLS_PKCS11 */
#endif
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
* Set various Exim expansion vars *
*************************************************/
-#define exim_gnutls_cert_err(Label) do { \
- if (rc != GNUTLS_E_SUCCESS) { \
- DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \
- return rc; } } while (0)
+#define exim_gnutls_cert_err(Label) \
+ do \
+ { \
+ if (rc != GNUTLS_E_SUCCESS) \
+ { \
+ DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \
+ (Label), gnutls_strerror(rc)); \
+ return rc; \
+ } \
+ } while (0)
static int
import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp)
/* Set the OCSP stapling server info */
-#ifdef EXPERIMENTAL_OCSP
+#ifndef DISABLE_OCSP
if ( !host /* server */
&& tls_ocsp_file
)
/* 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");
}
}
{
DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n",
cert_list, cert_list_size);
- if (state->verify_requirement == VERIFY_REQUIRED)
+ if (state->verify_requirement >= VERIFY_REQUIRED)
return tls_error(US"certificate verification failed",
"no certificate received from peer", state->host);
return OK;
const char *ctn = gnutls_certificate_type_get_name(ct);
DEBUG(D_tls)
debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn);
- if (state->verify_requirement == VERIFY_REQUIRED)
+ if (state->verify_requirement >= VERIFY_REQUIRED)
return tls_error(US"certificate verification not possible, unhandled type",
ctn, state->host);
return OK;
}
-#define exim_gnutls_peer_err(Label) do { \
- if (rc != GNUTLS_E_SUCCESS) { \
- DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \
- if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \
- return OK; } } while (0)
+#define exim_gnutls_peer_err(Label) \
+ do { \
+ if (rc != GNUTLS_E_SUCCESS) \
+ { \
+ DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \
+ (Label), gnutls_strerror(rc)); \
+ if (state->verify_requirement >= VERIFY_REQUIRED) \
+ return tls_error((Label), gnutls_strerror(rc), state->host); \
+ return OK; \
+ } \
+ } while (0)
rc = import_cert(&cert_list[0], &crt);
exim_gnutls_peer_err(US"cert 0");
/* Handle the result of verification. INVALID seems to be set as well
as REVOKED, but leave the test for both. */
-if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED))
+if (rc < 0 ||
+ verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)
+ )
{
state->peer_cert_verified = FALSE;
if (!*error)
? "certificate revoked" : "certificate invalid";
DEBUG(D_tls)
- debug_printf("TLS certificate verification failed (%s): peerdn=%s\n",
+ debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n",
*error, state->peerdn ? state->peerdn : US"<unset>");
- if (state->verify_requirement == VERIFY_REQUIRED)
+ if (state->verify_requirement >= VERIFY_REQUIRED)
{
- gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
+ gnutls_alert_send(state->session,
+ GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
return FALSE;
}
DEBUG(D_tls)
debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n");
}
+
else
{
+#ifdef EXPERIMENTAL_CERTNAMES
+ if (state->verify_requirement == VERIFY_WITHHOST)
+ {
+ int sep = 0;
+ 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))
+ break;
+ if (!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;
+ }
+ }
+#endif
state->peer_cert_verified = TRUE;
- DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n",
+ 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_TPDA
+/*
+We use this callback to get observability and detail-level control
+for an exim client TLS connection, raising a TPDA tls:cert event
+for each cert in the chain presented by the server. Any event
+can deny verification.
+
+Return 0 for the handshake to continue or non-zero to terminate.
+*/
+
+static int
+client_verify_cb(gnutls_session_t session)
+{
+const gnutls_datum * cert_list;
+unsigned int cert_list_size = 0;
+gnutls_x509_crt_t crt;
+int rc;
+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 (tpda_raise_event(state->event_action,
+ US"tls:cert", string_sprintf("%d", cert_list_size)) == DEFER)
+ {
+ log_write(0, LOG_MAIN,
+ "SSL verify denied by event-action: depth=%d", cert_list_size);
+ return 1; /* reject */
+ }
+ state->tlsp->peercert = NULL;
+ }
+
+return 0;
+}
+
+#endif
if (verify_check_host(&tls_verify_hosts) == OK)
{
- DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n");
+ DEBUG(D_tls)
+ debug_printf("TLS: a client certificate will be required.\n");
state->verify_requirement = VERIFY_REQUIRED;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
}
else if (verify_check_host(&tls_try_verify_hosts) == OK)
{
- DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n");
+ DEBUG(D_tls)
+ debug_printf("TLS: a client certificate will be requested but not required.\n");
state->verify_requirement = VERIFY_OPTIONAL;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST);
}
else
{
- DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n");
+ DEBUG(D_tls)
+ debug_printf("TLS: a client certificate will not be requested.\n");
state->verify_requirement = VERIFY_NONE;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE);
}
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)
{
-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
+#ifndef DISABLE_OCSP
BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp,
NULL, host->name, host->address, NULL) == OK;
BOOL request_ocsp = require_ocsp ? TRUE
verify_check_host(&ob->tls_verify_hosts) == OK
)
{
- DEBUG(D_tls) debug_printf("TLS: server certificate verification required.\n");
- state->verify_requirement = VERIFY_REQUIRED;
+#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;
+ }
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
}
else if (verify_check_host(&ob->tls_try_verify_hosts) == OK)
{
- DEBUG(D_tls) debug_printf("TLS: server certificate verification optional.\n");
+ 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_REQUEST);
}
else
{
- DEBUG(D_tls) debug_printf("TLS: server certificate verification not required.\n");
+ DEBUG(D_tls)
+ debug_printf("TLS: server certificate verification not required.\n");
state->verify_requirement = VERIFY_NONE;
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_TPDA
+if (tb->tpda_event_action)
+ {
+ state->event_action = tb->tpda_event_action;
+ gnutls_session_set_ptr(state->session, state);
+ gnutls_certificate_set_verify_function(state->x509_cred, client_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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