* 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 */
#include <gnutls/x509.h>
/* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */
#include <gnutls/crypto.h>
+/* needed to disable PKCS11 autoload unless requested */
+#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
be set to point to content in one of these instances, as appropriate for
the stage of the process lifetime.
-Not handled here: globals tls_active, tls_bits, tls_cipher, tls_peerdn,
-tls_certificate_verified, tls_channelbinding_b64, tls_sni.
+Not handled here: global tls_channelbinding_b64.
*/
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;
+ 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 *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() */
uschar *xfer_buffer;
int xfer_buffer_lwm;
int xfer_buffer_hwm;
int xfer_eof;
int xfer_error;
-
- uschar cipherbuf[256];
} exim_gnutls_state_st;
static const exim_gnutls_state_st exim_gnutls_state_init = {
- NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE,
- NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL,
+ 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,
+#ifdef EXPERIMENTAL_EVENT
+ NULL,
+#endif
+ NULL,
NULL, 0, 0, 0, 0,
- ""
};
/* Not only do we have our own APIs which don't pass around state, assuming
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 exim_gnutls_state_st *current_global_tls_state;
/* dh_params are initialised once within the lifetime of a process using TLS;
if we used TLS in a long-lived daemon, we'd have to reconsider this. But we
/* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup
the library logging; a value less than 0 disables the calls to set up logging
callbacks. */
-#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1
+#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL
+# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1
+#endif
-#define EXIM_CLIENT_DH_MIN_BITS 1024
+#ifndef EXIM_CLIENT_DH_MIN_BITS
+# 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. */
-#define EXIM_SERVER_DH_BITS_PRE2_12 1024
+#ifndef EXIM_SERVER_DH_BITS_PRE2_12
+# define EXIM_SERVER_DH_BITS_PRE2_12 1024
+#endif
#define exim_gnutls_err_check(Label) do { \
if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0)
-#define exim_gnutls_err_debugreturn0(Label) do { \
- if (rc != GNUTLS_E_SUCCESS) { \
- DEBUG(D_tls) debug_printf("TLS failure: %s: %s", (Label), gnutls_strerror(rc)); \
- return 0; } } while (0)
-
#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 */
#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
-Also:
- current_global_tls_state for API limitations
+ 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)
+extract_exim_vars_from_tls_state(exim_gnutls_state_st * state)
{
-gnutls_protocol_t protocol;
gnutls_cipher_algorithm_t cipher;
-gnutls_kx_algorithm_t kx;
-gnutls_mac_algorithm_t mac;
-uschar *p;
#ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING
int old_pool;
int rc;
gnutls_datum_t channel;
#endif
+tls_support * tlsp = state->tlsp;
-current_global_tls_state = state;
-
-tls_active = state->fd_out;
+tlsp->active = state->fd_out;
cipher = gnutls_cipher_get(state->session);
/* returns size in "bytes" */
-tls_bits = gnutls_cipher_get_key_size(cipher) * 8;
-
-if (!*state->cipherbuf)
- {
- protocol = gnutls_protocol_get_version(state->session);
- mac = gnutls_mac_get(state->session);
- kx = gnutls_kx_get(state->session);
-
- string_format(state->cipherbuf, sizeof(state->cipherbuf),
- "%s:%s:%u",
- gnutls_protocol_get_name(protocol),
- gnutls_cipher_suite_get_name(kx, cipher, mac),
- tls_bits);
+tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
- /* I don't see a way that spaces could occur, in the current GnuTLS
- code base, but it was a concern in the old code and perhaps older GnuTLS
- releases did return "TLS 1.0"; play it safe, just in case. */
- for (p = state->cipherbuf; *p != '\0'; ++p)
- if (isspace(*p))
- *p = '-';
- }
-tls_cipher = state->cipherbuf;
+tlsp->cipher = state->ciphersuite;
-DEBUG(D_tls) debug_printf("cipher: %s\n", tls_cipher);
+DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite);
-tls_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
-tls_peerdn = state->peerdn;
+/* peercert is set in peer_status() */
+tlsp->peerdn = state->peerdn;
+tlsp->sni = state->received_sni;
-tls_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;
+ }
}
waste a bit of effort, but it doesn't seem worth messing around with locking to
prevent this.
-Argument:
- host NULL for server, server for client (for error handling)
-
Returns: OK/DEFER/FAIL
*/
int fd, rc;
unsigned int dh_bits;
gnutls_datum m;
-uschar filename[PATH_MAX];
+uschar filename_buf[PATH_MAX];
+uschar *filename = NULL;
size_t sz;
+uschar *exp_tls_dhparam;
+BOOL use_file_in_spool = FALSE;
+BOOL use_fixed_file = FALSE;
host_item *host = NULL; /* dummy for macros */
DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n");
rc = gnutls_dh_params_init(&dh_server_params);
exim_gnutls_err_check(US"gnutls_dh_params_init");
+m.data = NULL;
+m.size = 0;
+
+if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam))
+ return DEFER;
+
+if (!exp_tls_dhparam)
+ {
+ DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n");
+ m.data = US std_dh_prime_default();
+ m.size = Ustrlen(m.data);
+ }
+else if (Ustrcmp(exp_tls_dhparam, "historic") == 0)
+ use_file_in_spool = TRUE;
+else if (Ustrcmp(exp_tls_dhparam, "none") == 0)
+ {
+ DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
+ return OK;
+ }
+else if (exp_tls_dhparam[0] != '/')
+ {
+ m.data = US std_dh_prime_named(exp_tls_dhparam);
+ if (m.data == NULL)
+ return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL);
+ m.size = Ustrlen(m.data);
+ }
+else
+ {
+ use_fixed_file = TRUE;
+ filename = exp_tls_dhparam;
+ }
+
+if (m.data)
+ {
+ rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM);
+ exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3");
+ DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n");
+ return OK;
+ }
+
#ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS
/* If you change this constant, also change dh_param_fn_ext so that we can use a
different filename and ensure we have sufficient bits. */
if (!dh_bits)
return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL);
DEBUG(D_tls)
- debug_printf("GnuTLS tells us that for D-H PL, NORMAL is %d bits.\n",
+ debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n",
dh_bits);
#else
dh_bits = EXIM_SERVER_DH_BITS_PRE2_12;
dh_bits);
#endif
-if (!string_format(filename, sizeof(filename),
- "%s/gnutls-params-%d", spool_directory, dh_bits))
- return tls_error(US"overlong filename", NULL, NULL);
+/* Some clients have hard-coded limits. */
+if (dh_bits > tls_dh_max_bits)
+ {
+ DEBUG(D_tls)
+ debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n",
+ tls_dh_max_bits);
+ dh_bits = tls_dh_max_bits;
+ }
+
+if (use_file_in_spool)
+ {
+ if (!string_format(filename_buf, sizeof(filename_buf),
+ "%s/gnutls-params-%d", spool_directory, dh_bits))
+ return tls_error(US"overlong filename", NULL, NULL);
+ filename = filename_buf;
+ }
/* Open the cache file for reading and if successful, read it and set up the
parameters. */
if (rc < 0)
{
uschar *temp_fn;
+ unsigned int dh_bits_gen = dh_bits;
if ((PATH_MAX - Ustrlen(filename)) < 10)
return tls_error(US"Filename too long to generate replacement",
return tls_error(US"Unable to open temp file", strerror(errno), NULL);
(void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */
- DEBUG(D_tls) debug_printf("generating %d bits Diffie-Hellman key ...\n", dh_bits);
- rc = gnutls_dh_params_generate2(dh_server_params, dh_bits);
+ /* GnuTLS overshoots!
+ * If we ask for 2236, we might get 2237 or more.
+ * But there's no way to ask GnuTLS how many bits there really are.
+ * We can ask how many bits were used in a TLS session, but that's it!
+ * The prime itself is hidden behind too much abstraction.
+ * So we ask for less, and proceed on a wing and a prayer.
+ * First attempt, subtracted 3 for 2233 and got 2240.
+ */
+ if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10)
+ {
+ dh_bits_gen = dh_bits - 10;
+ DEBUG(D_tls)
+ debug_printf("being paranoid about DH generation, make it '%d' bits'\n",
+ dh_bits_gen);
+ }
+
+ DEBUG(D_tls)
+ debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n",
+ dh_bits_gen);
+ rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen);
exim_gnutls_err_check(US"gnutls_dh_params_generate2");
/* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time,
m.data = malloc(m.size);
if (m.data == NULL)
return tls_error(US"memory allocation failed", strerror(errno), NULL);
+ /* this will return a size 1 less than the allocation size above */
rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM,
m.data, &sz);
if (rc != GNUTLS_E_SUCCESS)
free(m.data);
exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real");
}
+ m.size = sz; /* shrink by 1, probably */
sz = write_to_fd_buf(fd, m.data, (size_t) m.size);
if (sz != m.size)
static int
tls_expand_session_files(exim_gnutls_state_st *state)
{
+struct stat statbuf;
int rc;
const host_item *host = state->host; /* macro should be reconsidered? */
uschar *saved_tls_certificate = NULL;
int cert_count;
/* We check for tls_sni *before* expansion. */
-if (!state->host)
+if (!host) /* server */
{
if (!state->received_sni)
{
- if (Ustrstr(state->tls_certificate, US"tls_sni"))
+ if (state->tls_certificate &&
+ (Ustrstr(state->tls_certificate, US"tls_sni") ||
+ Ustrstr(state->tls_certificate, US"tls_in_sni") ||
+ Ustrstr(state->tls_certificate, US"tls_out_sni")
+ ))
{
DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n");
state->trigger_sni_changes = TRUE;
}
else
{
+ /* useful for debugging */
saved_tls_certificate = state->exp_tls_certificate;
saved_tls_privatekey = state->exp_tls_privatekey;
saved_tls_verify_certificates = state->exp_tls_verify_certificates;
}
}
+rc = gnutls_certificate_allocate_credentials(&state->x509_cred);
+exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials");
+
/* remember: expand_check_tlsvar() is expand_check() but fiddling with
state members, assuming consistent naming; and expand_check() returns
false if expansion failed, unless expansion was forced to fail. */
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");
if (state->exp_tls_certificate && *state->exp_tls_certificate)
{
- BOOL setit = TRUE;
DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n",
state->exp_tls_certificate, state->exp_tls_privatekey);
if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) &&
(Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0))
{
- DEBUG(D_tls) debug_printf("cert and key unchanged with SNI.\n");
- setit = FALSE;
+ DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n");
}
else
{
- DEBUG(D_tls) debug_printf("SNI changed cert/key pair.\n");
+ DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n");
}
}
- if (setit)
- {
- rc = gnutls_certificate_set_x509_key_file(state->x509_cred,
- CS state->exp_tls_certificate, CS state->exp_tls_privatekey,
- GNUTLS_X509_FMT_PEM);
- exim_gnutls_err_check(
- string_sprintf("cert/key setup: cert=%s key=%s",
- state->exp_tls_certificate, state->exp_tls_privatekey));
- }
+ rc = gnutls_certificate_set_x509_key_file(state->x509_cred,
+ CS state->exp_tls_certificate, CS state->exp_tls_privatekey,
+ GNUTLS_X509_FMT_PEM);
+ exim_gnutls_err_check(
+ string_sprintf("cert/key setup: cert=%s key=%s",
+ state->exp_tls_certificate, state->exp_tls_privatekey));
+ 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 (!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
if (state->tls_verify_certificates && *state->tls_verify_certificates)
{
- struct stat statbuf;
- BOOL setit_vc = TRUE, setit_crl = TRUE;
-
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;
- if (state->received_sni)
+ if (!(state->exp_tls_verify_certificates &&
+ *state->exp_tls_verify_certificates))
{
- if (Ustrcmp(state->exp_tls_verify_certificates, saved_tls_verify_certificates) == 0)
- setit_vc = FALSE;
- if (Ustrcmp(state->exp_tls_crl, saved_tls_crl) == 0)
- setit_crl = FALSE;
- }
-
- /* nb: early exit; change if add more expansions to this function */
- if (!(setit_vc || setit_crl))
+ DEBUG(D_tls)
+ debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n");
+ /* With no tls_verify_certificates, we ignore tls_crl too */
return OK;
+ }
+ }
+else
+ {
+ DEBUG(D_tls)
+ debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n");
+ return OK;
+ }
+#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
+ {
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));
+ "(tls_verify_certificates): %s", state->exp_tls_verify_certificates,
+ strerror(errno));
return DEFER;
}
- if (!S_ISREG(statbuf.st_mode))
+#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 not a file: \"%s\"\n%s\n",
- state->exp_tls_verify_certificates,
- S_ISDIR(statbuf.st_mode)
- ? " it's a directory, that's OpenSSL, this is GnuTLS"
- : " (not a directory either)");
+ 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 not a file",
- state->exp_tls_verify_certificates);
+ "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);
-
- /* If the CA cert file is empty, there's no point in loading the CRL file,
- as we aren't verifying, so checking for revocation is pointless. */
+ state->exp_tls_verify_certificates, statbuf.st_size);
- if (statbuf.st_size > 0)
+ if (statbuf.st_size == 0)
{
- if (setit_vc)
- {
- 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");
- }
- DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count);
- }
+ DEBUG(D_tls)
+ debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
+ return OK;
+ }
- if (setit_crl && state->tls_crl && *state->tls_crl)
- {
- if (state->exp_tls_crl && *state->exp_tls_crl)
- {
- DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl);
- rc = gnutls_certificate_set_x509_crl_file(state->x509_cred,
- CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM);
- exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file");
- }
- }
- } /* statbuf.st_size */
- } /* tls_verify_certificates */
+ 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);
+ }
+
+if (cert_count < 0)
+ {
+ rc = cert_count;
+ exim_gnutls_err_check(US"setting certificate trust");
+ }
+DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count);
+
+if (state->tls_crl && *state->tls_crl &&
+ state->exp_tls_crl && *state->exp_tls_crl)
+ {
+ DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl);
+ cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred,
+ CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM);
+ if (cert_count < 0)
+ {
+ rc = cert_count;
+ exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file");
+ }
+ DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count);
+ }
return OK;
-/* also above, during verify_certificates/crl, during SNI, if unchanged */
}
+/*************************************************
+* Set X.509 state variables *
+*************************************************/
+
+/* In GnuTLS, the registered cert/key are not replaced by a later
+set of a cert/key, so for SNI support we need a whole new x509_cred
+structure. Which means various other non-re-expanded pieces of state
+need to be re-set in the new struct, so the setting logic is pulled
+out to this.
+
+Arguments:
+ state exim_gnutls_state_st *
+
+Returns: OK/DEFER/FAIL
+*/
+
+static int
+tls_set_remaining_x509(exim_gnutls_state_st *state)
+{
+int rc;
+const host_item *host = state->host; /* macro should be reconsidered? */
+
+/* Create D-H parameters, or read them from the cache file. This function does
+its own SMTP error messaging. This only happens for the server, TLS D-H ignores
+client-side params. */
+
+if (!state->host)
+ {
+ if (!dh_server_params)
+ {
+ rc = init_server_dh();
+ if (rc != OK) return rc;
+ }
+ gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params);
+ }
+
+/* Link the credentials to the session. */
+
+rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred);
+exim_gnutls_err_check(US"gnutls_credentials_set");
+
+return OK;
+}
+
/*************************************************
* Initialize for GnuTLS *
*************************************************/
cas CA certs file
crl CRL file
require_ciphers tls_require_ciphers setting
+ caller_state returned state-info structure
Returns: OK/DEFER/FAIL
*/
{
DEBUG(D_tls) debug_printf("GnuTLS global init required.\n");
+#ifdef HAVE_GNUTLS_PKCS11
+ /* By default, gnutls_global_init will init PKCS11 support in auto mode,
+ which loads modules from a config file, which sounds good and may be wanted
+ 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_allow_auto_pkcs11)
+ {
+ rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL);
+ exim_gnutls_err_check(US"gnutls_pkcs11_init");
+ }
+#endif
+
rc = gnutls_global_init();
exim_gnutls_err_check(US"gnutls_global_init");
{
state = &state_client;
memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
+ state->tlsp = &tls_out;
DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n");
rc = gnutls_init(&state->session, GNUTLS_CLIENT);
}
{
state = &state_server;
memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
+ state->tlsp = &tls_in;
DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n");
rc = gnutls_init(&state->session, GNUTLS_SERVER);
}
state->tls_certificate = certificate;
state->tls_privatekey = privatekey;
+state->tls_require_ciphers = require_ciphers;
state->tls_sni = sni;
state->tls_verify_certificates = cas;
state->tls_crl = crl;
-rc = gnutls_certificate_allocate_credentials(&state->x509_cred);
-exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials");
-
/* This handles the variables that might get re-expanded after TLS SNI;
that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */
rc = tls_expand_session_files(state);
if (rc != OK) return rc;
-/* Create D-H parameters, or read them from the cache file. This function does
-its own SMTP error messaging. This only happens for the server, TLS D-H ignores
-client-side params. */
-
-if (!host)
- {
- rc = init_server_dh();
- if (rc != OK) return rc;
- gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params);
- }
-
-/* Link the credentials to the session. */
+/* These are all other parts of the x509_cred handling, since SNI in GnuTLS
+requires a new structure afterwards. */
-rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred);
-exim_gnutls_err_check(US"gnutls_credentials_set");
+rc = tls_set_remaining_x509(state);
+if (rc != OK) return rc;
/* set SNI in client, only */
if (host)
{
- if (!expand_check_tlsvar(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. */
}
if (want_default_priorities)
{
+ DEBUG(D_tls)
+ debug_printf("GnuTLS using default session cipher/priority \"%s\"\n",
+ exim_default_gnutls_priority);
rc = gnutls_priority_init(&state->priority_cache,
exim_default_gnutls_priority, &errpos);
p = US exim_default_gnutls_priority;
}
*caller_state = state;
-/* needs to happen before callbacks during handshake */
-current_global_tls_state = state;
return OK;
}
-
/*************************************************
* Extract peer information *
*************************************************/
/* Called from both server and client code.
-Only this is allowed to set state->peerdn and we use that to detect double-calls.
+Only this is allowed to set state->peerdn and state->have_set_peerdn
+and we use that to detect double-calls.
+
+NOTE: the state blocks last while the TLS connection is up, which is fine
+for logging in the server side, but for the client side, we log after teardown
+in src/deliver.c. While the session is up, we can twist about states and
+repoint tls_* globals, but those variables used for logging or other variable
+expansion that happens _after_ delivery need to have a longer life-time.
+
+So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from
+doing this more than once per generation of a state context. We set them in
+the state context, and repoint tls_* to them. After the state goes away, the
+tls_* copies of the pointers remain valid and client delivery logging is happy.
+
+tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues
+don't apply.
Arguments:
state exim_gnutls_state_st *
static int
peer_status(exim_gnutls_state_st *state)
{
+uschar cipherbuf[256];
const gnutls_datum *cert_list;
-int rc;
+int old_pool, rc;
unsigned int cert_list_size = 0;
+gnutls_protocol_t protocol;
+gnutls_cipher_algorithm_t cipher;
+gnutls_kx_algorithm_t kx;
+gnutls_mac_algorithm_t mac;
gnutls_certificate_type_t ct;
gnutls_x509_crt_t crt;
-uschar *dn_buf;
+uschar *p, *dn_buf;
size_t sz;
-if (state->peerdn)
+if (state->have_set_peerdn)
return OK;
+state->have_set_peerdn = TRUE;
-state->peerdn = US"unknown";
+state->peerdn = NULL;
+/* tls_cipher */
+cipher = gnutls_cipher_get(state->session);
+protocol = gnutls_protocol_get_version(state->session);
+mac = gnutls_mac_get(state->session);
+kx = gnutls_kx_get(state->session);
+
+string_format(cipherbuf, sizeof(cipherbuf),
+ "%s:%s:%d",
+ gnutls_protocol_get_name(protocol),
+ gnutls_cipher_suite_get_name(kx, cipher, mac),
+ (int) gnutls_cipher_get_key_size(cipher) * 8);
+
+/* I don't see a way that spaces could occur, in the current GnuTLS
+code base, but it was a concern in the old code and perhaps older GnuTLS
+releases did return "TLS 1.0"; play it safe, just in case. */
+for (p = cipherbuf; *p != '\0'; ++p)
+ if (isspace(*p))
+ *p = '-';
+old_pool = store_pool;
+store_pool = POOL_PERM;
+state->ciphersuite = string_copy(cipherbuf);
+store_pool = old_pool;
+state->tlsp->cipher = state->ciphersuite;
+
+/* tls_peerdn */
cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size);
if (cert_list == NULL || cert_list_size == 0)
{
- state->peerdn = US"unknown (no certificate)";
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;
if (ct != GNUTLS_CRT_X509)
{
const char *ctn = gnutls_certificate_type_get_name(ct);
- state->peerdn = string_sprintf("unknown (type %s)", ctn);
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");
-rc = gnutls_x509_crt_init(&crt);
-exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)");
+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",
- *error, state->peerdn);
+ 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 overriden (host in tls_try_verify_hosts)\n");
+ 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", state->peerdn);
+ DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n",
+ state->peerdn ? state->peerdn : US"<unset>");
}
-tls_peerdn = state->peerdn;
+state->tlsp->peerdn = state->peerdn;
return TRUE;
}
static void
exim_gnutls_logger_cb(int level, const char *message)
{
- DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s\n", level, message);
+ size_t len = strlen(message);
+ if (len < 1)
+ {
+ DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level);
+ return;
+ }
+ DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message,
+ message[len-1] == '\n' ? "" : "\n");
}
#endif
For inability to get SNI information, we return 0.
We only return non-zero if re-setup failed.
+Only used for server-side TLS.
*/
static int
{
char sni_name[MAX_HOST_LEN];
size_t data_len = MAX_HOST_LEN;
-exim_gnutls_state_st *state = current_global_tls_state;
+exim_gnutls_state_st *state = &state_server;
unsigned int sni_type;
int rc, old_pool;
rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0);
-exim_gnutls_err_debugreturn0("gnutls_server_name_get()");
+if (rc != GNUTLS_E_SUCCESS)
+ {
+ DEBUG(D_tls) {
+ if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
+ debug_printf("TLS: no SNI presented in handshake.\n");
+ else
+ debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n",
+ gnutls_strerror(rc), rc);
+ };
+ return 0;
+ }
+
if (sni_type != GNUTLS_NAME_DNS)
{
DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type);
store_pool = old_pool;
/* We set this one now so that variable expansions below will work */
-tls_sni = state->received_sni;
+state->tlsp->sni = state->received_sni;
DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name,
state->trigger_sni_changes ? "" : " (unused for certificate selection)");
return GNUTLS_E_APPLICATION_ERROR_MIN;
}
-rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred);
-return (rc == GNUTLS_E_SUCCESS) ? 0 : rc;
+rc = tls_set_remaining_x509(state);
+if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN;
+
+return 0;
}
+#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 */
exim_gnutls_state_st *state = NULL;
/* Check for previous activation */
-/* nb: this will not be TLS callout safe, needs reworking as part of that. */
-
-if (tls_active >= 0)
+if (tls_in.active >= 0)
{
tls_error(US"STARTTLS received after TLS started", "", NULL);
smtp_printf("554 Already in TLS\r\n");
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. */
the response. Other smtp_printf() calls do not need it, because in non-TLS
mode, the fflush() happens when smtp_getc() is called. */
-if (!tls_on_connect)
+if (!state->tlsp->on_connect)
{
smtp_printf("220 TLS go ahead\r\n");
fflush(smtp_out);
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);
do
{
rc = gnutls_handshake(state->session);
- } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED));
+ } while ((rc == GNUTLS_E_AGAIN) ||
+ (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen));
alarm(0);
if (rc != GNUTLS_E_SUCCESS)
/* 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. */
+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)
- dhparam DH parameter file (ignored, we're a client)
- 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
- 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 *dhparam ARG_UNUSED,
- uschar *certificate, uschar *privatekey, uschar *sni,
- uschar *verify_certs, uschar *verify_crl,
- uschar *require_ciphers, int timeout)
+ address_item *addr ARG_UNUSED,
+ transport_instance *tb
+#ifdef EXPERIMENTAL_DANE
+ , dne_answer * unused_tlsa_dnsa
+#endif
+ )
{
+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;
-gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_DH_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;
+ }
-if (verify_certs == NULL)
+ 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 ( ( 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);
- } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED));
+ } while ((rc == GNUTLS_E_AGAIN) ||
+ (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen));
alarm(0);
+if (rc != GNUTLS_E_SUCCESS)
+ return tls_error(US"gnutls_handshake",
+ sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host);
+
DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n");
/* Verify late */
!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; always safe within server */
+/* Sets various Exim expansion variables; may need to adjust for ACL callouts */
extract_exim_vars_from_tls_state(state);
*/
void
-tls_close(BOOL shutdown)
+tls_close(BOOL is_server, BOOL shutdown)
{
-exim_gnutls_state_st *state = current_global_tls_state;
+exim_gnutls_state_st *state = is_server ? &state_server : &state_client;
-if (tls_active < 0) return; /* TLS was not active */
+if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */
if (shutdown)
{
gnutls_deinit(state->session);
+state->tlsp->active = -1;
memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
if ((state_server.session == NULL) && (state_client.session == NULL))
exim_gnutls_base_init_done = FALSE;
}
-tls_active = -1;
}
/* This gets the next byte from the TLS input buffer. If the buffer is empty,
it refills the buffer via the GnuTLS reading function.
+Only used by the server-side TLS.
This feeds DKIM and should be used for all message-body reads.
int
tls_getc(void)
{
-exim_gnutls_state_st *state = current_global_tls_state;
+exim_gnutls_state_st *state = &state_server;
if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm)
{
ssize_t inbytes;
gnutls_deinit(state->session);
state->session = NULL;
- tls_active = -1;
- tls_bits = 0;
- tls_certificate_verified = FALSE;
+ state->tlsp->active = -1;
+ state->tlsp->bits = 0;
+ state->tlsp->certificate_verified = FALSE;
tls_channelbinding_b64 = NULL;
- tls_cipher = NULL;
- tls_peerdn = NULL;
+ state->tlsp->cipher = NULL;
+ state->tlsp->peercert = NULL;
+ state->tlsp->peerdn = NULL;
return smtp_getc();
}
/* This does not feed DKIM, so if the caller uses this for reading message body,
then the caller must feed DKIM.
+
Arguments:
buff buffer of data
len size of buffer
*/
int
-tls_read(uschar *buff, size_t len)
+tls_read(BOOL is_server, uschar *buff, size_t len)
{
-exim_gnutls_state_st *state = current_global_tls_state;
+exim_gnutls_state_st *state = is_server ? &state_server : &state_client;
ssize_t inbytes;
if (len > INT_MAX)
/*
Arguments:
+ is_server channel specifier
buff buffer of data
len number of bytes
*/
int
-tls_write(const uschar *buff, size_t len)
+tls_write(BOOL is_server, const uschar *buff, size_t len)
{
ssize_t outbytes;
size_t left = len;
-exim_gnutls_state_st *state = current_global_tls_state;
+exim_gnutls_state_st *state = is_server ? &state_server : &state_client;
DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left);
while (left > 0)
+/*************************************************
+* Let tls_require_ciphers be checked at startup *
+*************************************************/
+
+/* The tls_require_ciphers option, if set, must be something which the
+library can parse.
+
+Returns: NULL on success, or error message
+*/
+
+uschar *
+tls_validate_require_cipher(void)
+{
+int rc;
+uschar *expciphers = NULL;
+gnutls_priority_t priority_cache;
+const char *errpos;
+
+#define validate_check_rc(Label) do { \
+ if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \
+ return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0)
+#define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0)
+
+if (exim_gnutls_base_init_done)
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "already initialised GnuTLS, Exim developer bug");
+
+#ifdef HAVE_GNUTLS_PKCS11
+if (!gnutls_allow_auto_pkcs11)
+ {
+ rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL);
+ validate_check_rc(US"gnutls_pkcs11_init");
+ }
+#endif
+rc = gnutls_global_init();
+validate_check_rc(US"gnutls_global_init()");
+exim_gnutls_base_init_done = TRUE;
+
+if (!(tls_require_ciphers && *tls_require_ciphers))
+ return_deinit(NULL);
+
+if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers))
+ return_deinit(US"failed to expand tls_require_ciphers");
+
+if (!(expciphers && *expciphers))
+ return_deinit(NULL);
+
+DEBUG(D_tls)
+ debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
+
+rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos);
+validate_check_rc(string_sprintf(
+ "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"",
+ expciphers, errpos - CS expciphers, errpos));
+
+#undef return_deinit
+#undef validate_check_rc
+gnutls_global_deinit();
+
+return NULL;
+}
+
+
+
+
/*************************************************
* Report the library versions. *
*************************************************/
gnutls_check_version(NULL));
}
+/* vi: aw ai sw=2
+*/
/* End of tls-gnu.c */
projects / exim.git / blobdiff