* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2012 */
+/* 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
+#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
/* GnuTLS 2 vs 3
/* Values for verify_requirement */
-enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED };
+enum peer_verify_requirement
+ { 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
*/
typedef struct exim_gnutls_state {
- gnutls_session_t session;
+ gnutls_session_t session;
gnutls_certificate_credentials_t x509_cred;
- gnutls_priority_t priority_cache;
+ gnutls_priority_t priority_cache;
enum peer_verify_requirement verify_requirement;
- int fd_in;
- int fd_out;
- BOOL peer_cert_verified;
- BOOL trigger_sni_changes;
- BOOL have_set_peerdn;
+ int fd_in;
+ int fd_out;
+ BOOL peer_cert_verified;
+ BOOL trigger_sni_changes;
+ BOOL have_set_peerdn;
const struct host_item *host;
- uschar *peerdn;
- uschar *ciphersuite;
- uschar *received_sni;
+ gnutls_x509_crt_t peercert;
+ uschar *peerdn;
+ uschar *ciphersuite;
+ uschar *received_sni;
const uschar *tls_certificate;
const uschar *tls_privatekey;
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;
+ const uschar *exp_tls_verify_cert_hostnames;
+#ifdef EXPERIMENTAL_EVENT
+ uschar *event_action;
+#endif
tls_support *tlsp; /* set in tls_init() */
NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+ NULL,
+#ifdef EXPERIMENTAL_EVENT
+ 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;
static BOOL exim_gnutls_base_init_done = FALSE;
+static BOOL gnutls_buggy_ocsp = FALSE;
+
/* ------------------------------------------------------------------------ */
/* macros */
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_PKCS11
+# 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 */
#endif
static int exim_sni_handling_cb(gnutls_session_t session);
+#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 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)
+
+static int
+import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp)
+{
+int rc;
+
+rc = gnutls_x509_crt_init(crtp);
+exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)");
+
+rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER);
+exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]");
+
+return rc;
+}
+
+#undef exim_gnutls_cert_err
+
+
/* We set various Exim global variables from the state, once a session has
been established. With TLS callouts, may need to change this to stack
variables, or just re-call it with the server state after client callout
has finished.
-Make sure anything set here is inset in tls_getc().
+Make sure anything set here is unset in tls_getc().
Sets:
tls_active fd
tls_certificate_verified bool indicator
tls_channelbinding_b64 for some SASL mechanisms
tls_cipher a string
+ tls_peercert pointer to library internal
tls_peerdn a string
tls_sni a (UTF-8) string
+ tls_ourcert pointer to library internal
Argument:
state the relevant exim_gnutls_state_st *
*/
static void
-extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server)
+extract_exim_vars_from_tls_state(exim_gnutls_state_st * state)
{
gnutls_cipher_algorithm_t cipher;
#ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING
int rc;
gnutls_datum_t channel;
#endif
+tls_support * tlsp = state->tlsp;
-state->tlsp->active = state->fd_out;
+tlsp->active = state->fd_out;
cipher = gnutls_cipher_get(state->session);
/* returns size in "bytes" */
-state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
+tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
-state->tlsp->cipher = state->ciphersuite;
+tlsp->cipher = state->ciphersuite;
DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite);
-state->tlsp->certificate_verified = state->peer_cert_verified;
+tlsp->certificate_verified = state->peer_cert_verified;
/* note that tls_channelbinding_b64 is not saved to the spool file, since it's
only available for use for authenticators while this TLS session is running. */
}
#endif
-state->tlsp->peerdn = state->peerdn;
-state->tlsp->sni = state->received_sni;
+/* peercert is set in peer_status() */
+tlsp->peerdn = state->peerdn;
+tlsp->sni = state->received_sni;
+
+/* record our certificate */
+ {
+ const gnutls_datum * cert = gnutls_certificate_get_ours(state->session);
+ gnutls_x509_crt_t crt;
+
+ tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL;
+ }
}
int cert_count;
/* We check for tls_sni *before* expansion. */
-if (!state->host)
+if (!host) /* server */
{
if (!state->received_sni)
{
if ((state->exp_tls_certificate == NULL) ||
(*state->exp_tls_certificate == '\0'))
{
- if (state->host == NULL)
+ if (!host)
return tls_error(US"no TLS server certificate is specified", NULL, NULL);
else
DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n");
DEBUG(D_tls) debug_printf("TLS: cert/key registered\n");
} /* tls_certificate */
+
+/* Set the OCSP stapling server info */
+
+#ifndef DISABLE_OCSP
+if ( !host /* server */
+ && tls_ocsp_file
+ )
+ {
+ if (gnutls_buggy_ocsp)
+ {
+ DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n");
+ }
+ else
+ {
+ if (!expand_check(tls_ocsp_file, US"tls_ocsp_file",
+ &state->exp_tls_ocsp_file))
+ return DEFER;
+
+ /* Use the full callback method for stapling just to get observability.
+ More efficient would be to read the file once only, if it never changed
+ (due to SNI). Would need restart on file update, or watch datestamp. */
+
+ gnutls_certificate_set_ocsp_status_request_function(state->x509_cred,
+ server_ocsp_stapling_cb, state->exp_tls_ocsp_file);
+
+ DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file);
+ }
+ }
+#endif
+
+
/* Set the trusted CAs file if one is provided, and then add the CRL if one is
provided. Experiment shows that, if the certificate file is empty, an unhelpful
error message is provided. However, if we just refrain from setting anything up
{
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);
* Initialize for GnuTLS *
*************************************************/
+
+static BOOL
+tls_is_buggy_ocsp(void)
+{
+const uschar * s;
+uschar maj, mid, mic;
+
+s = CUS gnutls_check_version(NULL);
+maj = atoi(CCS s);
+if (maj == 3)
+ {
+ while (*s && *s != '.') s++;
+ mid = atoi(CCS ++s);
+ if (mid <= 2)
+ return TRUE;
+ else if (mid >= 5)
+ return FALSE;
+ else
+ {
+ while (*s && *s != '.') s++;
+ mic = atoi(CCS ++s);
+ return mic <= (mid == 3 ? 16 : 3);
+ }
+ }
+return FALSE;
+}
+
+
+
/* Called from both server and client code. In the case of a server, errors
before actual TLS negotiation return DEFER.
by some sysadmin, but also means in common configurations that GNOME keyring
environment variables are used and so breaks for users calling mailq.
To prevent this, we init PKCS11 first, which is the documented approach. */
- if (!gnutls_enable_pkcs11)
+ if (!gnutls_allow_auto_pkcs11)
{
rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL);
exim_gnutls_err_check(US"gnutls_pkcs11_init");
}
#endif
+ if ((gnutls_buggy_ocsp = tls_is_buggy_ocsp()))
+ log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version");
+
exim_gnutls_base_init_done = TRUE;
}
/* 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");
}
}
"have an SNI set for a client [%s]\n", state->tls_sni);
/* This is the priority string support,
-http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
+http://www.gnutls.org/manual/html_node/Priority-Strings.html
and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols.
This was backwards incompatible, but means Exim no longer needs to track
all algorithms and provide string forms for them. */
-
/*************************************************
* Extract peer information *
*************************************************/
{
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 = gnutls_x509_crt_init(&crt);
-exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)");
+rc = import_cert(&cert_list[0], &crt);
+exim_gnutls_peer_err(US"cert 0");
+
+state->tlsp->peercert = state->peercert = crt;
-rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER);
-exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]");
sz = 0;
rc = gnutls_x509_crt_get_dn(crt, NULL, &sz);
if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER)
dn_buf = store_get_perm(sz);
rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz);
exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]");
+
state->peerdn = dn_buf;
return OK;
*error = NULL;
-rc = peer_status(state);
-if (rc != OK)
+if ((rc = peer_status(state)) != OK)
{
verify = GNUTLS_CERT_INVALID;
- *error = "not supplied";
+ *error = "certificate not supplied";
}
else
- {
rc = gnutls_certificate_verify_peers2(state->session, &verify);
- }
/* 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)) != 0)
+if (rc < 0 ||
+ verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)
+ )
{
state->peer_cert_verified = FALSE;
- if (*error == NULL)
- *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid";
+ if (!*error)
+ *error = verify & GNUTLS_CERT_REVOKED
+ ? "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
{
+ if (state->exp_tls_verify_cert_hostnames)
+ {
+ int sep = 0;
+ 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))
+ break;
+ if (!name)
+ {
+ DEBUG(D_tls)
+ debug_printf("TLS certificate verification failed: cert name mismatch\n");
+ if (state->verify_requirement >= VERIFY_REQUIRED)
+ {
+ gnutls_alert_send(state->session,
+ GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
+ return FALSE;
+ }
+ return TRUE;
+ }
+ }
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>");
}
+#ifndef DISABLE_OCSP
+
+static int
+server_ocsp_stapling_cb(gnutls_session_t session, void * ptr,
+ gnutls_datum_t * ocsp_response)
+{
+int ret;
+
+if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0)
+ {
+ DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n",
+ (char *)ptr);
+ tls_in.ocsp = OCSP_NOT_RESP;
+ return GNUTLS_E_NO_CERTIFICATE_STATUS;
+ }
+
+tls_in.ocsp = OCSP_VFY_NOT_TRIED;
+return 0;
+}
+
+#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
+
+
/* ------------------------------------------------------------------------ */
/* Exported functions */
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);
}
+#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. */
if (!state->tlsp->on_connect)
{
smtp_printf("220 TLS go ahead\r\n");
- fflush(smtp_out); /*XXX JGH */
+ fflush(smtp_out);
}
/* Now negotiate the TLS session. We put our own timer on it, since it seems
that the GnuTLS library doesn't. */
gnutls_transport_set_ptr2(state->session,
- (gnutls_transport_ptr)fileno(smtp_in),
- (gnutls_transport_ptr)fileno(smtp_out));
+ (gnutls_transport_ptr)(long) fileno(smtp_in),
+ (gnutls_transport_ptr)(long) fileno(smtp_out));
state->fd_in = fileno(smtp_in);
state->fd_out = fileno(smtp_out);
/* Verify after the fact */
-if (state->verify_requirement != VERIFY_NONE)
+if ( state->verify_requirement != VERIFY_NONE
+ && !verify_certificate(state, &error))
{
- if (!verify_certificate(state, &error))
+ if (state->verify_requirement != VERIFY_OPTIONAL)
{
- if (state->verify_requirement == VERIFY_OPTIONAL)
- {
- DEBUG(D_tls)
- debug_printf("TLS: continuing on only because verification was optional, after: %s\n",
- error);
- }
- else
- {
- tls_error(US"certificate verification failed", error, NULL);
- return FAIL;
- }
+ tls_error(US"certificate verification failed", error, NULL);
+ return FAIL;
}
+ DEBUG(D_tls)
+ debug_printf("TLS: continuing on only because verification was optional, after: %s\n",
+ error);
}
/* Figure out peer DN, and if authenticated, etc. */
/* Sets various Exim expansion variables; always safe within server */
-extract_exim_vars_from_tls_state(state, TRUE);
+extract_exim_vars_from_tls_state(state);
/* TLS has been set up. Adjust the input functions to read via TLS,
and initialize appropriately. */
+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)
- certificate certificate file
- privatekey private key file
- sni TLS SNI to send to remote host
- verify_certs file for certificate verify
- verify_crl CRL for verify
- require_ciphers list of allowed ciphers or NULL
- dh_min_bits minimum number of bits acceptable in server's DH prime
- timeout startup timeout
+ 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,
- uschar *certificate, uschar *privatekey, uschar *sni,
- uschar *verify_certs, uschar *verify_crl,
- uschar *require_ciphers,
-#ifdef EXPERIMENTAL_OCSP
- uschar *require_ocsp ARG_UNUSED,
+ transport_instance *tb
+#ifdef EXPERIMENTAL_DANE
+ , dne_answer * unused_tlsa_dnsa
#endif
- int dh_min_bits, int timeout)
+ )
{
+smtp_transport_options_block *ob =
+ (smtp_transport_options_block *)tb->options_block;
int rc;
const char *error;
exim_gnutls_state_st *state = NULL;
+#ifndef DISABLE_OCSP
+BOOL require_ocsp =
+ verify_check_given_host(&ob->hosts_require_ocsp, host) == OK;
+BOOL request_ocsp = require_ocsp ? TRUE
+ : 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);
-rc = tls_init(host, certificate, privatekey,
- sni, verify_certs, verify_crl, require_ciphers, &state);
-if (rc != OK) return rc;
+if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey,
+ ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl,
+ ob->tls_require_ciphers, &state)) != OK)
+ return rc;
-if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS)
{
- DEBUG(D_tls)
- debug_printf("WARNING: tls_dh_min_bits far too low, clamping %d up to %d\n",
- dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS);
- dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS;
+ int dh_min_bits = ob->tls_dh_min_bits;
+ if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS)
+ {
+ DEBUG(D_tls)
+ debug_printf("WARNING: tls_dh_min_bits far too low,"
+ " clamping %d up to %d\n",
+ dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS);
+ dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS;
+ }
+
+ DEBUG(D_tls) debug_printf("Setting D-H prime minimum"
+ " acceptable bits to %d\n",
+ dh_min_bits);
+ gnutls_dh_set_prime_bits(state->session, dh_min_bits);
}
-DEBUG(D_tls) debug_printf("Setting D-H prime minimum acceptable bits to %d\n",
- dh_min_bits);
-gnutls_dh_set_prime_bits(state->session, dh_min_bits);
+/* Stick to the old behaviour for compatibility if tls_verify_certificates is
+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 (verify_certs == NULL)
+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
+ )
{
- DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n");
- state->verify_requirement = VERIFY_NONE;
- /* we still ask for it, to log it, etc */
+ 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_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_REQUEST);
}
else
{
- 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);
+ 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);
}
-gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd);
+#ifndef DISABLE_OCSP
+ /* supported since GnuTLS 3.1.3 */
+if (request_ocsp)
+ {
+ DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n");
+ if ((rc = gnutls_ocsp_status_request_enable_client(state->session,
+ NULL, 0, NULL)) != OK)
+ return tls_error(US"cert-status-req",
+ gnutls_strerror(rc), state->host);
+ tls_out.ocsp = OCSP_NOT_RESP;
+ }
+#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;
+DEBUG(D_tls) debug_printf("about to gnutls_handshake\n");
/* There doesn't seem to be a built-in timeout on connection. */
sigalrm_seen = FALSE;
-alarm(timeout);
+alarm(ob->command_timeout);
do
{
rc = gnutls_handshake(state->session);
!verify_certificate(state, &error))
return tls_error(US"certificate verification failed", error, state->host);
+#ifndef DISABLE_OCSP
+if (require_ocsp)
+ {
+ DEBUG(D_tls)
+ {
+ gnutls_datum_t stapling;
+ gnutls_ocsp_resp_t resp;
+ gnutls_datum_t printed;
+ if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0
+ && (rc= gnutls_ocsp_resp_init(&resp)) == 0
+ && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0
+ && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0
+ )
+ {
+ debug_printf("%.4096s", printed.data);
+ gnutls_free(printed.data);
+ }
+ else
+ (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host);
+ }
+
+ if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0)
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ return tls_error(US"certificate status check failed", NULL, state->host);
+ }
+ DEBUG(D_tls) debug_printf("Passed OCSP checking\n");
+ tls_out.ocsp = OCSP_VFIED;
+ }
+#endif
+
/* Figure out peer DN, and if authenticated, etc. */
-rc = peer_status(state);
-if (rc != OK) return rc;
+if ((rc = peer_status(state)) != OK)
+ return rc;
/* Sets various Exim expansion variables; may need to adjust for ACL callouts */
-extract_exim_vars_from_tls_state(state, FALSE);
+extract_exim_vars_from_tls_state(state);
return OK;
}
state->tlsp->active = -1;
state->tlsp->bits = 0;
state->tlsp->certificate_verified = FALSE;
- tls_channelbinding_b64 = NULL; /*XXX JGH */
+ tls_channelbinding_b64 = NULL;
state->tlsp->cipher = NULL;
+ state->tlsp->peercert = NULL;
state->tlsp->peerdn = NULL;
return smtp_getc();
"already initialised GnuTLS, Exim developer bug");
#ifdef HAVE_GNUTLS_PKCS11
-if (!gnutls_enable_pkcs11)
+if (!gnutls_allow_auto_pkcs11)
{
rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL);
validate_check_rc(US"gnutls_pkcs11_init");
gnutls_check_version(NULL));
}
+/* vi: aw ai sw=2
+*/
/* End of tls-gnu.c */
projects / exim.git / blobdiff