* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2017 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
/* Copyright (c) Phil Pennock 2012 */
#if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP)
# define SUPPORT_SRV_OCSP_STACK
#endif
-#if GNUTLS_VERSION_NUMBER >= 0x030000 && defined(EXPERIMENTAL_DANE)
-# define SUPPORT_DANE
+
+#ifdef SUPPORT_DANE
+# if GNUTLS_VERSION_NUMBER >= 0x030000
+# define DANESSL_USAGE_DANE_TA 2
+# define DANESSL_USAGE_DANE_EE 3
+# else
+# error GnuTLS version too early for DANE
+# endif
+# if GNUTLS_VERSION_NUMBER < 0x999999
+# define GNUTLS_BROKEN_DANE_VALIDATION
+# endif
#endif
#ifndef DISABLE_OCSP
*/
static BOOL
-verify_certificate(exim_gnutls_state_st *state, uschar ** errstr)
+verify_certificate(exim_gnutls_state_st * state, uschar ** errstr)
{
int rc;
uint verify;
dane_state_t s;
dane_query_t r;
- const gnutls_datum_t * certlist;
uint lsize;
+ const gnutls_datum_t * certlist =
+ gnutls_certificate_get_peers(state->session, &lsize);
+ int usage = tls_out.tlsa_usage;
+
+# ifdef GNUTLS_BROKEN_DANE_VALIDATION
+ /* Split the TLSA records into two sets, TA and EE selectors. Run the
+ dane-verification separately so that we know which selector verified;
+ then we know whether to do CA-chain-verification and name-verification
+ (needed for TA but not EE). */
+
+ if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE)))
+ { /* a mixed-usage bundle */
+ int i, j, nrec;
+ const char ** dd;
+ int * ddl;
+
+ for(nrec = 0; state->dane_data_len[nrec]; ) nrec++;
+ nrec++;
+
+ dd = store_get(nrec * sizeof(uschar *));
+ ddl = store_get(nrec * sizeof(int));
+ nrec--;
+
+ if ((rc = dane_state_init(&s, 0)))
+ goto tlsa_prob;
+
+ for (usage = DANESSL_USAGE_DANE_EE;
+ usage >= DANESSL_USAGE_DANE_TA; usage--)
+ { /* take records with this usage */
+ for (j = i = 0; i < nrec; i++)
+ if (state->dane_data[i][0] == usage)
+ {
+ dd[j] = state->dane_data[i];
+ ddl[j++] = state->dane_data_len[i];
+ }
+ if (j)
+ {
+ dd[j] = NULL;
+ ddl[j] = 0;
+
+ if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0)))
+ goto tlsa_prob;
+
+ if ((rc = dane_verify_crt_raw(s, certlist, lsize,
+ gnutls_certificate_type_get(state->session),
+ r, 0,
+ usage == DANESSL_USAGE_DANE_EE
+ ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0,
+ &verify)))
+ {
+ DEBUG(D_tls)
+ debug_printf("TLSA record problem: %s\n", dane_strerror(rc));
+ }
+ else if (verify == 0) /* verification passed */
+ {
+ usage = 1 << usage;
+ break;
+ }
+ }
+ }
- certlist = gnutls_certificate_get_peers(state->session, &lsize);
-
- if ( (rc = dane_state_init(&s, 0))
- || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len,
- 1, 0))
- || (rc = dane_verify_crt_raw(s, certlist, lsize,
- gnutls_certificate_type_get(state->session),
- r, 0, 0, &verify))
- )
-
+ if (rc) goto tlsa_prob;
+ }
+ else
+# endif
{
- *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc));
- goto badcert;
+ if ( (rc = dane_state_init(&s, 0))
+ || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len,
+ 1, 0))
+ || (rc = dane_verify_crt_raw(s, certlist, lsize,
+ gnutls_certificate_type_get(state->session),
+ r, 0,
+# ifdef GNUTLS_BROKEN_DANE_VALIDATION
+ usage == (1 << DANESSL_USAGE_DANE_EE)
+ ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0,
+# else
+ 0,
+# endif
+ &verify))
+ )
+ goto tlsa_prob;
}
- if (verify != 0)
+
+ if (verify != 0) /* verification failed */
{
gnutls_datum_t str;
(void) dane_verification_status_print(verify, &str, 0);
goto badcert;
}
state->peer_dane_verified = TRUE;
+
+# ifdef GNUTLS_BROKEN_DANE_VALIDATION
+ /* If a TA-mode TLSA record was used for verification we must additionally
+ verify the CA chain and the cert name. For EE-mode, skip it. */
+
+ if (usage & (1 << DANESSL_USAGE_DANE_EE))
+# endif
+ {
+ state->peer_cert_verified = TRUE;
+ goto goodcert;
+ }
}
#endif
/* Handle the result of verification. INVALID is set if any others are. */
-if (rc < 0 ||
- verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)
- )
+if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED))
{
state->peer_cert_verified = FALSE;
if (!*errstr)
state->peerdn ? state->peerdn : US"<unset>");
}
-state->tlsp->peerdn = state->peerdn;
-return TRUE;
+goodcert:
+ state->tlsp->peerdn = state->peerdn;
+ return TRUE;
+
+#ifdef SUPPORT_DANE
+tlsa_prob:
+ *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc));
+#endif
badcert:
gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE);
We point at the dnsa data not copy it, so it must remain valid until
after verification is done.*/
-static void
+static BOOL
dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa)
{
dns_record * rr;
) if (rr->type == T_TLSA)
{
const uschar * p = rr->data;
- uint8_t usage = *p;
+ uint8_t usage = p[0], sel = p[1], type = p[2];
+
+ DEBUG(D_tls)
+ debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size);
+
+ if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE)
+ || (sel != 0 && sel != 1)
+ )
+ continue;
+ switch(type)
+ {
+ case 0: /* Full: cannot check at present */
+ break;
+ case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */
+ break;
+ case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */
+ break;
+ default: continue;
+ }
tls_out.tlsa_usage |= 1<<usage;
dane_data[i] = p;
dane_data_len[i++] = rr->size;
}
+
+if (!i) return FALSE;
+
dane_data[i] = NULL;
dane_data_len[i] = 0;
state->dane_data = (char * const *)dane_data;
state->dane_data_len = dane_data_len;
+return TRUE;
}
#endif
tls_client_start(int fd, host_item *host,
address_item *addr ARG_UNUSED,
transport_instance * tb,
-#ifdef EXPERIMENTAL_DANE
+#ifdef SUPPORT_DANE
dns_answer * tlsa_dnsa,
#endif
uschar ** errstr)
the specified host patterns if one of them is defined */
#ifdef SUPPORT_DANE
-if (tlsa_dnsa)
+if (tlsa_dnsa && dane_tlsa_load(state, tlsa_dnsa))
{
DEBUG(D_tls)
debug_printf("TLS: server certificate DANE required.\n");
state->verify_requirement = VERIFY_DANE;
gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
- dane_tlsa_load(state, tlsa_dnsa);
}
else
#endif
sigalrm_seen = FALSE;
alarm(ob->command_timeout);
do
- {
rc = gnutls_handshake(state->session);
- } while ((rc == GNUTLS_E_AGAIN) ||
- (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen));
+while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen);
alarm(0);
if (rc != GNUTLS_E_SUCCESS)
DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n",
state->session, state->xfer_buffer, ssl_xfer_buffer_size);
+sigalrm_seen = FALSE;
if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
inbytes = gnutls_record_recv(state->session, state->xfer_buffer,
MIN(ssl_xfer_buffer_size, lim));
projects / exim.git / blobdiff