Add support for AUTH PLAIN

crypto.c

@@ -383,7 +383,7 @@ smtp_auth_md5(int fd, char *login, char *password)
 		       " AUTH cram-md5 not available: %s", neterr);
 		/* if cram-md5 is not available */
 		free(temp);
-		return (-1);
+		return (1);
 	}
 
 	/* skip 3 char status + 1 char space */
@@ -405,7 +405,7 @@ smtp_auth_md5(int fd, char *login, char *password)
 	len = base64_encode(buffer, strlen(buffer), &temp);
 	if (len < 0) {
 		syslog(LOG_ERR, "can not encode auth reply: %m");
-		return (-1);
+		return (1);
 	}
 
 	/* send answer */
@@ -414,7 +414,7 @@ smtp_auth_md5(int fd, char *login, char *password)
 	if (read_remote(fd, 0, NULL) != 2) {
 		syslog(LOG_WARNING, "remote delivery deferred:"
 				" AUTH cram-md5 failed: %s", neterr);
-		return (-2);
+		return (-1);
 	}
 
 	return (0);

dma.h

@@ -166,6 +166,7 @@ struct mx_hostentry {
 struct smtp_auth_mechanisms {
 	int cram_md5;
 	int login;
+	int plain;
 };
 
 struct smtp_features {

net.c

@@ -258,77 +258,132 @@ read_remote(int fd, int extbufsize, char *extbuf)
 	return (-1);
 }
 
+static int
+smtp_auth_login(int fd, char *login, char* password)
+{
+	char *temp;
+	int len, res = 0;
+
+	/* Send AUTH command according to RFC 2554 */
+	send_remote_command(fd, "AUTH LOGIN");
+	if (read_remote(fd, 0, NULL) != 3) {
+		syslog(LOG_NOTICE, "remote delivery deferred:"
+		    " AUTH login not available: %s",
+		    neterr);
+		return (1);
+	}
+
+	len = base64_encode(login, strlen(login), &temp);
+	if (len < 0) {
+encerr:
+		syslog(LOG_ERR, "can not encode auth reply: %m");
+		return (1);
+	}
+
+	send_remote_command(fd, "%s", temp);
+	free(temp);
+	res = read_remote(fd, 0, NULL);
+	if (res != 3) {
+		syslog(LOG_NOTICE, "remote delivery %s: AUTH login failed: %s",
+		    res == 5 ? "failed" : "deferred", neterr);
+		return (res == 5 ? -1 : 1);
+	}
+
+	len = base64_encode(password, strlen(password), &temp);
+	if (len < 0)
+		goto encerr;
+
+	send_remote_command(fd, "%s", temp);
+	free(temp);
+	res = read_remote(fd, 0, NULL);
+	if (res != 2) {
+		syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s",
+		    res == 5 ? "failed" : "deferred", neterr);
+		return (res == 5 ? -1 : 1);
+	}
+
+	return 0;
+}
+
+static int
+smtp_auth_plain(int fd, char *login, char* password)
+{
+	char *temp, *authstr;
+	int len, res = 0;
+
+	/* Send AUTH command according to RFC 2554 */
+	send_remote_command(fd, "AUTH PLAIN");
+	if (read_remote(fd, 0, NULL) != 3) {
+		syslog(LOG_NOTICE, "remote delivery deferred:"
+		    " AUTH plain not available: %s",
+		    neterr);
+		return (1);
+	}
+
+	len = asprintf(&authstr, "%c%s%c%s", '/0', login, '/0', password);
+	if (len < 0) {
+		syslog(LOG_ERR, "can not format auth reply: %m");
+		return (1);
+	}
+
+	len = base64_encode(authstr, len, &temp);
+	free(authstr);
+	if (len < 0) {
+		syslog(LOG_ERR, "can not encode auth reply: %m");
+		return (1);
+	}
+	send_remote_command(fd, "%s", temp);
+	free(temp);
+	res = read_remote(fd, 0, NULL);
+	if (res != 2) {
+		syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s",
+		    res == 5 ? "failed" : "deferred", neterr);
+		return (res == 5 ? -1 : 1);
+	}
+
+	return 0;
+}
+
 /*
  * Handle SMTP authentication
  */
 static int
-smtp_login(int fd, char *login, char* password, const struct smtp_features* features)
+smtp_auth(int fd, char *login, char* password, const struct smtp_features* features)
 {
-	char *temp;
-	int len, res = 0;
+	int res = 1;
 
 	// CRAM-MD5
 	if (features->auth.cram_md5) {
 		res = smtp_auth_md5(fd, login, password);
-		if (res == 0) {
-			return (0);
-		} else if (res == -2) {
-		/*
-		 * If the return code is -2, then then the login attempt failed,
-		 * do not try other login mechanisms
-		 */
-			return (1);
+		if (res != 1) {
+			return res;
 		}
 	}
 
-	// LOGIN
-	if (features->auth.login) {
-		if ((config.features & INSECURE) != 0 ||
+	if ((config.features & INSECURE) != 0 ||
 		    (config.features & SECURETRANSFER) != 0) {
-			/* Send AUTH command according to RFC 2554 */
-			send_remote_command(fd, "AUTH LOGIN");
-			if (read_remote(fd, 0, NULL) != 3) {
-				syslog(LOG_NOTICE, "remote delivery deferred:"
-						" AUTH login not available: %s",
-						neterr);
-				return (1);
-			}
 
-			len = base64_encode(login, strlen(login), &temp);
-			if (len < 0) {
-encerr:
-				syslog(LOG_ERR, "can not encode auth reply: %m");
-				return (1);
-			}
-
-			send_remote_command(fd, "%s", temp);
-			free(temp);
-			res = read_remote(fd, 0, NULL);
-			if (res != 3) {
-				syslog(LOG_NOTICE, "remote delivery %s: AUTH login failed: %s",
-				       res == 5 ? "failed" : "deferred", neterr);
-				return (res == 5 ? -1 : 1);
+		// LOGIN
+		if (features->auth.login) {
+			res = smtp_auth_login(fd, login, password);
+			if (res != 1) {
+				return res;
 			}
+		}
 
-			len = base64_encode(password, strlen(password), &temp);
-			if (len < 0)
-				goto encerr;
-
-			send_remote_command(fd, "%s", temp);
-			free(temp);
-			res = read_remote(fd, 0, NULL);
-			if (res != 2) {
-				syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s",
-						res == 5 ? "failed" : "deferred", neterr);
-				return (res == 5 ? -1 : 1);
+		// PLAIN
+		if (features->auth.plain) {
+			res = smtp_auth_plain(fd, login, password);
+			if (res != 1) {
+				return res;
 			}
-		} else {
-			syslog(LOG_WARNING, "non-encrypted SMTP login is disabled in config, so skipping it. ");
-			return (1);
-		}
+		}	
+	} else if (features->auth.login || features->auth.plain) {
+		syslog(LOG_WARNING, "non-encrypted SMTP authentication is disabled in config, so skipping it. ");
+		return (1);
 	}
 
-	return (0);
+	return res;
 }
 
 static int
@@ -381,6 +436,9 @@ static void parse_auth_line(char* line, struct smtp_auth_mechanisms* auth) {
 		else if (strcmp(method, "LOGIN") == 0)
 			auth->login = 1;
 
+		else if (strcmp(method, "PLAIN") == 0)
+			auth->plain = 1;
+
 		method = strtok(NULL, " ");
 	}
 }
@@ -469,6 +527,9 @@ int perform_server_greeting(int fd, struct smtp_features* features) {
 	if (features->auth.login) {
 		syslog(LOG_DEBUG, "  Server supports LOGIN authentication");
 	}
+	if (features->auth.plain) {
+		syslog(LOG_DEBUG, "  Server supports PLAIN authentication");
+	}
 
 	return 0;
 }
@@ -552,18 +613,21 @@ deliver_to_host(struct qitem *it, struct mx_hostentry *host)
 		 * Check if the user wants plain text login without using
 		 * encryption.
 		 */
-		syslog(LOG_INFO, "using SMTP authentication for user %s", a->login);
-		error = smtp_login(fd, a->login, a->password, &features);
-		if (error < 0) {
-			syslog(LOG_ERR, "remote delivery failed:"
-					" SMTP login failed: %m");
-			snprintf(errmsg, sizeof(errmsg), "SMTP login to %s failed", host->host);
-			error = -1;
-			goto out;
-		}
-		/* SMTP login is not available, so try without */
-		else if (error > 0) {
-			syslog(LOG_WARNING, "SMTP login not available. Trying without.");
+		if (features.auth.cram_md5 || features.auth.login || features.auth.plain) {
+			syslog(LOG_INFO, "using SMTP authentication for user %s", a->login);
+			error = smtp_auth(fd, a->login, a->password, &features);
+			if (error < 0) {
+				snprintf(errmsg, sizeof(errmsg), "SMTP auth to %s failed", host->host);
+				error = -1;
+				goto out;
+			}
+			/* SMTP auth is not available, so try without */
+			else if (error > 0) {
+				syslog(LOG_WARNING, "SMTP auth not available. Trying without.");
+			}
+		} else {
+			syslog(LOG_ERR, "No supported AUTH mechanisms in common with server."
+					" Skipping authentication.");
 		}
 	}