+/* Do the client side of smtp-level authentication */
+/*
+Arguments:
+ buffer EHLO response from server (gets overwritten)
+ addrlist chain of potential addresses to deliver
+ host host to deliver to
+ ob transport options
+ ibp, obp comms channel control blocks
+
+Returns:
+ OK Success, or failed (but not required): global "smtp_authenticated" set
+ DEFER Failed authentication (and was required)
+ ERROR Internal problem
+
+ FAIL_SEND Failed communications - transmit
+ FAIL - response
+*/
+
+int
+smtp_auth(uschar *buffer, unsigned bufsize, address_item *addrlist, host_item *host,
+ smtp_transport_options_block *ob, BOOL is_esmtp,
+ smtp_inblock *ibp, smtp_outblock *obp)
+{
+int require_auth;
+uschar *fail_reason = US"server did not advertise AUTH support";
+
+smtp_authenticated = FALSE;
+client_authenticator = client_authenticated_id = client_authenticated_sender = NULL;
+require_auth = verify_check_given_host(&ob->hosts_require_auth, host);
+
+if (is_esmtp && !regex_AUTH) regex_AUTH =
+ regex_must_compile(US"\\n250[\\s\\-]AUTH\\s+([\\-\\w\\s]+)(?:\\n|$)",
+ FALSE, TRUE);
+
+if (is_esmtp && regex_match_and_setup(regex_AUTH, buffer, 0, -1))
+ {
+ uschar *names = string_copyn(expand_nstring[1], expand_nlength[1]);
+ expand_nmax = -1; /* reset */
+
+ /* Must not do this check until after we have saved the result of the
+ regex match above. */
+
+ if (require_auth == OK ||
+ verify_check_given_host(&ob->hosts_try_auth, host) == OK)
+ {
+ auth_instance *au;
+ fail_reason = US"no common mechanisms were found";
+
+ DEBUG(D_transport) debug_printf("scanning authentication mechanisms\n");
+
+ /* Scan the configured authenticators looking for one which is configured
+ for use as a client, which is not suppressed by client_condition, and
+ whose name matches an authentication mechanism supported by the server.
+ If one is found, attempt to authenticate by calling its client function.
+ */
+
+ for (au = auths; !smtp_authenticated && au != NULL; au = au->next)
+ {
+ uschar *p = names;
+ if (!au->client ||
+ (au->client_condition != NULL &&
+ !expand_check_condition(au->client_condition, au->name,
+ US"client authenticator")))
+ {
+ DEBUG(D_transport) debug_printf("skipping %s authenticator: %s\n",
+ au->name,
+ (au->client)? "client_condition is false" :
+ "not configured as a client");
+ continue;
+ }
+
+ /* Loop to scan supported server mechanisms */
+
+ while (*p != 0)
+ {
+ int rc;
+ int len = Ustrlen(au->public_name);
+ while (isspace(*p)) p++;
+
+ if (strncmpic(au->public_name, p, len) != 0 ||
+ (p[len] != 0 && !isspace(p[len])))
+ {
+ while (*p != 0 && !isspace(*p)) p++;
+ continue;
+ }
+
+ /* Found data for a listed mechanism. Call its client entry. Set
+ a flag in the outblock so that data is overwritten after sending so
+ that reflections don't show it. */
+
+ fail_reason = US"authentication attempt(s) failed";
+ obp->authenticating = TRUE;
+ rc = (au->info->clientcode)(au, ibp, obp,
+ ob->command_timeout, buffer, bufsize);
+ obp->authenticating = FALSE;
+ DEBUG(D_transport) debug_printf("%s authenticator yielded %d\n",
+ au->name, rc);
+
+ /* A temporary authentication failure must hold up delivery to
+ this host. After a permanent authentication failure, we carry on
+ to try other authentication methods. If all fail hard, try to
+ deliver the message unauthenticated unless require_auth was set. */
+
+ switch(rc)
+ {
+ case OK:
+ smtp_authenticated = TRUE; /* stops the outer loop */
+ client_authenticator = au->name;
+ if (au->set_client_id != NULL)
+ client_authenticated_id = expand_string(au->set_client_id);
+ break;
+
+ /* Failure after writing a command */
+
+ case FAIL_SEND:
+ return FAIL_SEND;
+
+ /* Failure after reading a response */
+
+ case FAIL:
+ if (errno != 0 || buffer[0] != '5') return FAIL;
+ log_write(0, LOG_MAIN, "%s authenticator failed H=%s [%s] %s",
+ au->name, host->name, host->address, buffer);
+ break;
+
+ /* Failure by some other means. In effect, the authenticator
+ decided it wasn't prepared to handle this case. Typically this
+ is the result of "fail" in an expansion string. Do we need to
+ log anything here? Feb 2006: a message is now put in the buffer
+ if logging is required. */
+
+ case CANCELLED:
+ if (*buffer != 0)
+ log_write(0, LOG_MAIN, "%s authenticator cancelled "
+ "authentication H=%s [%s] %s", au->name, host->name,
+ host->address, buffer);
+ break;
+
+ /* Internal problem, message in buffer. */
+
+ case ERROR:
+ set_errno_nohost(addrlist, ERRNO_AUTHPROB, string_copy(buffer),
+ DEFER, FALSE);
+ return ERROR;
+ }
+
+ break; /* If not authenticated, try next authenticator */
+ } /* Loop for scanning supported server mechanisms */
+ } /* Loop for further authenticators */
+ }
+ }
+
+/* If we haven't authenticated, but are required to, give up. */
+
+if (require_auth == OK && !smtp_authenticated)
+ {
+ set_errno_nohost(addrlist, ERRNO_AUTHFAIL,
+ string_sprintf("authentication required but %s", fail_reason), DEFER,
+ FALSE);
+ return DEFER;
+ }
+
+return OK;
+}
+
+
+/* Construct AUTH appendix string for MAIL TO */
+/*
+Arguments
+ buffer to build string
+ addrlist chain of potential addresses to deliver
+ ob transport options
+
+Globals smtp_authenticated
+ client_authenticated_sender
+Return True on error, otherwise buffer has (possibly empty) terminated string
+*/
+
+BOOL
+smtp_mail_auth_str(uschar *buffer, unsigned bufsize, address_item *addrlist,
+ smtp_transport_options_block *ob)
+{
+uschar *local_authenticated_sender = authenticated_sender;
+
+#ifdef notdef
+ debug_printf("smtp_mail_auth_str: as<%s> os<%s> SA<%s>\n", authenticated_sender, ob->authenticated_sender, smtp_authenticated?"Y":"N");
+#endif
+
+if (ob->authenticated_sender != NULL)
+ {
+ uschar *new = expand_string(ob->authenticated_sender);
+ if (new == NULL)
+ {
+ if (!expand_string_forcedfail)
+ {
+ uschar *message = string_sprintf("failed to expand "
+ "authenticated_sender: %s", expand_string_message);
+ set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE);
+ return TRUE;
+ }
+ }
+ else if (new[0] != 0) local_authenticated_sender = new;
+ }
+
+/* Add the authenticated sender address if present */
+
+if ((smtp_authenticated || ob->authenticated_sender_force) &&
+ local_authenticated_sender != NULL)
+ {
+ string_format(buffer, bufsize, " AUTH=%s",
+ auth_xtextencode(local_authenticated_sender,
+ Ustrlen(local_authenticated_sender)));
+ client_authenticated_sender = string_copy(local_authenticated_sender);
+ }
+else
+ *buffer= 0;
+
+return FALSE;
+}
+
+
+
+#ifdef EXPERIMENTAL_DANE
+int
+tlsa_lookup(const host_item * host, dns_answer * dnsa,
+ BOOL dane_required, BOOL * dane)
+{
+/* move this out to host.c given the similarity to dns_lookup() ? */
+uschar buffer[300];
+const uschar * fullname = buffer;
+
+/* TLSA lookup string */
+(void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
+
+switch (dns_lookup(dnsa, buffer, T_TLSA, &fullname))
+ {
+ case DNS_AGAIN:
+ return DEFER; /* just defer this TLS'd conn */
+
+ default:
+ case DNS_FAIL:
+ if (dane_required)
+ return FAIL;
+ break;
+
+ case DNS_SUCCEED:
+ if (!dns_is_secure(dnsa))
+ {
+ log_write(0, LOG_MAIN, "DANE error: TLSA lookup not DNSSEC");
+ return DEFER;
+ }
+ *dane = TRUE;
+ break;
+ }
+return OK;
+}
+#endif
+
+
+
+typedef struct smtp_compare_s
+{
+ uschar *current_sender_address;
+ struct transport_instance *tblock;
+} smtp_compare_t;
+
+/*
+Create a unique string that identifies this message, it is based on
+sender_address, helo_data and tls_certificate if enabled. */
+
+static uschar *
+smtp_local_identity(uschar * sender, struct transport_instance * tblock)
+{
+address_item * addr1;
+uschar * if1 = US"";
+uschar * helo1 = US"";
+#ifdef SUPPORT_TLS
+uschar * tlsc1 = US"";
+#endif
+uschar * save_sender_address = sender_address;
+uschar * local_identity = NULL;
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)tblock->options_block;
+
+sender_address = sender;
+
+addr1 = deliver_make_addr (sender, TRUE);
+deliver_set_expansions(addr1);
+
+if (ob->interface)
+ if1 = expand_string(ob->interface);
+
+if (ob->helo_data)
+ helo1 = expand_string(ob->helo_data);
+
+#ifdef SUPPORT_TLS
+if (ob->tls_certificate)
+ tlsc1 = expand_string(ob->tls_certificate);
+local_identity = string_sprintf ("%s^%s^%s", if1, helo1, tlsc1);
+#else
+local_identity = string_sprintf ("%s^%s", if1, helo1);
+#endif
+
+deliver_set_expansions(NULL);
+sender_address = save_sender_address;
+
+return local_identity;
+}
+
+
+
+/* This routine is a callback that is called from transport_check_waiting.
+This function will evaluate the incoming message versus the previous
+message. If the incoming message is using a different local identity then
+we will veto this new message. */
+
+static BOOL
+smtp_are_same_identities(uschar * message_id, smtp_compare_t * s_compare)
+{
+
+uschar * message_local_identity,
+ * current_local_identity,
+ * new_sender_address;
+
+current_local_identity =
+ smtp_local_identity(s_compare->current_sender_address, s_compare->tblock);
+
+if (!(new_sender_address = deliver_get_sender_address(message_id)))
+ return 0;
+
+message_local_identity =
+ smtp_local_identity(new_sender_address, s_compare->tblock);
+
+return Ustrcmp(current_local_identity, message_local_identity) == 0;
+}
+
+
+
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