#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
/* GnuTLS 2 vs 3
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 {
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;
const uschar *tls_certificate;
uschar *exp_tls_crl;
uschar *exp_tls_require_ciphers;
+ 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, 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, 0, 0, 0, 0,
- ""
};
/* Not only do we have our own APIs which don't pass around state, assuming
second connection. */
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
static BOOL exim_gnutls_base_init_done = FALSE;
-/* ------------------------------------------------------------------------ */
-/* Callback declarations */
-
-static void exim_gnutls_logger_cb(int level, const char *message);
-static int exim_sni_handling_cb(gnutls_session_t session);
-
/* ------------------------------------------------------------------------ */
/* macros */
/* 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. */
+#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL
#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1
+#endif
+#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. */
+#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_PKCS11
#endif
+
+
+
+/* ------------------------------------------------------------------------ */
+/* Callback declarations */
+
+#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
+static void exim_gnutls_logger_cb(int level, const char *message);
+#endif
+
+static int exim_sni_handling_cb(gnutls_session_t session);
+
+
+
+
/* ------------------------------------------------------------------------ */
/* Static functions */
tls_cipher a string
tls_peerdn a string
tls_sni a (UTF-8) string
-Also:
- current_global_tls_state for API limitations
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, BOOL is_server)
{
-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
-current_global_tls_state = state;
-
-tls_active = state->fd_out;
+state->tlsp->active = state->fd_out;
cipher = gnutls_cipher_get(state->session);
/* returns size in "bytes" */
-tls_bits = gnutls_cipher_get_key_size(cipher) * 8;
+state->tlsp->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);
-
- /* 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;
+state->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;
+state->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;
-
-tls_sni = state->received_sni;
+state->tlsp->peerdn = state->peerdn;
+state->tlsp->sni = state->received_sni;
}
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 */
-const char * const dh_param_fn_ext = "normal"; /* change as dh_bits changes */
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");
-/* If you change this, also change dh_param_fn_ext so that we can use a
+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. */
dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL);
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 PK, NORMAL is %d bits.\n",
+ dh_bits);
+#else
+dh_bits = EXIM_SERVER_DH_BITS_PRE2_12;
+DEBUG(D_tls)
+ debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n",
+ dh_bits);
+#endif
+
+/* 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 (!string_format(filename, sizeof(filename),
- "%s/gnutls-params-%s", spool_directory, dh_param_fn_ext))
- return tls_error(US"overlong filename", NULL, NULL);
+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;
{
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 && *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 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;
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;
-
- 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;
}
+ }
+else
+ {
+ DEBUG(D_tls)
+ debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n");
+ return OK;
+ }
- if (!S_ISREG(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)");
- log_write(0, LOG_MAIN|LOG_PANIC,
- "tls_verify_certificates \"%s\" is not a file",
+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);
- return DEFER;
- }
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "tls_verify_certificates \"%s\" is a directory",
+ state->exp_tls_verify_certificates);
+ return DEFER;
+ }
- 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 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. */
+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)
- {
- 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);
- }
+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);
- 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 */
+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_enable_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. */
+/* These are all other parts of the x509_cred handling, since SNI in GnuTLS
+requires a new structure afterwards. */
-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. */
-
-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(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni))
return DEFER;
if (state->exp_tls_sni && *state->exp_tls_sni)
{
"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;
}
*************************************************/
/* 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 (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)
DEBUG(D_tls)
debug_printf("TLS certificate verification failed (%s): peerdn=%s\n",
- *error, state->peerdn);
+ *error, state->peerdn ? state->peerdn : US"<unset>");
if (state->verify_requirement == VERIFY_REQUIRED)
{
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
{
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;
}
* gnutls_global_set_log_function()
* gnutls_global_set_log_level() 0..9
*/
+#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
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
/* Called after client hello, should handle SNI work.
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;
}
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");
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);
+ fflush(smtp_out); /*XXX JGH */
}
/* Now negotiate the TLS session. We put our own timer on it, since it seems
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)
/* Sets various Exim expansion variables; always safe within server */
-extract_exim_vars_from_tls_state(state);
+extract_exim_vars_from_tls_state(state, TRUE);
/* TLS has been set up. Adjust the input functions to read via TLS,
and initialize appropriately. */
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
+ dh_min_bits minimum number of bits acceptable in server's DH prime
timeout startup timeout
Returns: OK/DEFER/FAIL (because using common functions),
int
tls_client_start(int fd, host_item *host,
- address_item *addr ARG_UNUSED, uschar *dhparam ARG_UNUSED,
+ address_item *addr ARG_UNUSED,
uschar *certificate, uschar *privatekey, uschar *sni,
uschar *verify_certs, uschar *verify_crl,
- uschar *require_ciphers, int timeout)
+ uschar *require_ciphers,
+#ifdef EXPERIMENTAL_OCSP
+ uschar *require_ocsp ARG_UNUSED,
+#endif
+ int dh_min_bits, int timeout)
{
int rc;
const char *error;
sni, verify_certs, verify_crl, require_ciphers, &state);
if (rc != OK) return rc;
-gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_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);
if (verify_certs == NULL)
{
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 */
rc = peer_status(state);
if (rc != 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);
+extract_exim_vars_from_tls_state(state, FALSE);
return OK;
}
*/
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;
- tls_channelbinding_b64 = NULL;
- tls_cipher = NULL;
- tls_peerdn = NULL;
+ state->tlsp->active = -1;
+ state->tlsp->bits = 0;
+ state->tlsp->certificate_verified = FALSE;
+ tls_channelbinding_b64 = NULL; /*XXX JGH */
+ state->tlsp->cipher = 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)
Returns a random number in range [0, max-1]
*/
+#ifdef HAVE_GNUTLS_RND
int
vaguely_random_number(int max)
{
* smooth distribution and cares enough then they should submit a patch then. */
return r % max;
}
+#else /* HAVE_GNUTLS_RND */
+int
+vaguely_random_number(int max)
+{
+ return vaguely_random_number_fallback(max);
+}
+#endif /* HAVE_GNUTLS_RND */
+
+
+
+
+/*************************************************
+* 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_enable_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;
+}
projects / exim.git / blobdiff