Instead of forbidding invalid session names, sanitize them.

cmd-new-session.c

@@ -70,13 +70,14 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 	struct cmd_find_state	*current = cmdq_get_current(item);
 	struct cmd_find_state	*target = cmdq_get_target(item);
 	struct client		*c = cmdq_get_client(item);
-	struct session		*s, *as, *groupwith;
+	struct session		*s, *as, *groupwith = NULL;
 	struct environ		*env;
 	struct options		*oo;
 	struct termios		 tio, *tiop;
-	struct session_group	*sg;
-	const char		*errstr, *template, *group, *prefix, *tmp;
+	struct session_group	*sg = NULL;
+	const char		*errstr, *template, *group, *tmp;
 	char			*cause, *cwd = NULL, *cp, *newname = NULL;
+	char			*name, *prefix = NULL;
 	int			 detached, already_attached, is_control = 0;
 	u_int			 sx, sy, dsx, dsy;
 	struct spawn_context	 sc;
@@ -98,11 +99,9 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 
 	tmp = args_get(args, 's');
 	if (tmp != NULL) {
-		newname = format_single(item, tmp, c, NULL, NULL, NULL);
-		if (!session_check_name(newname)) {
-			cmdq_error(item, "bad session name: %s", newname);
-			goto fail;
-		}
+		name = format_single(item, tmp, c, NULL, NULL, NULL);
+		newname = session_check_name(name);
+		free(name);
 	}
 	if (args_has(args, 'A')) {
 		if (newname != NULL)
@@ -126,24 +125,16 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 	group = args_get(args, 't');
 	if (group != NULL) {
 		groupwith = target->s;
-		if (groupwith == NULL) {
-			if (!session_check_name(group)) {
-				cmdq_error(item, "bad group name: %s", group);
-				goto fail;
-			}
+		if (groupwith == NULL)
 			sg = session_group_find(group);
-		} else
+		else
 			sg = session_group_contains(groupwith);
 		if (sg != NULL)
-			prefix = sg->name;
+			prefix = xstrdup(sg->name);
 		else if (groupwith != NULL)
-			prefix = groupwith->name;
+			prefix = xstrdup(groupwith->name);
 		else
-			prefix = group;
-	} else {
-		groupwith = NULL;
-		sg = NULL;
-		prefix = NULL;
+			prefix = session_check_name(group);
 	}
 
 	/* Set -d if no client. */
@@ -353,10 +344,12 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 
 	free(cwd);
 	free(newname);
+	free(prefix);
 	return (CMD_RETURN_NORMAL);
 
 fail:
 	free(cwd);
 	free(newname);
+	free(prefix);
 	return (CMD_RETURN_ERROR);
 }

cmd-rename-session.c

@@ -49,19 +49,15 @@ cmd_rename_session_exec(struct cmd *self, struct cmdq_item *item)
 	struct args		*args = cmd_get_args(self);
 	struct cmd_find_state	*target = cmdq_get_target(item);
 	struct session		*s = target->s;
-	char			*newname;
+	char			*newname, *tmp;
 
-	newname = format_single_from_target(item, args->argv[0]);
+	tmp = format_single_from_target(item, args->argv[0]);
+	newname = session_check_name(tmp);
+	free(tmp);
 	if (strcmp(newname, s->name) == 0) {
 		free(newname);
 		return (CMD_RETURN_NORMAL);
 	}
-
-	if (!session_check_name(newname)) {
-		cmdq_error(item, "bad session name: %s", newname);
-		free(newname);
-		return (CMD_RETURN_ERROR);
-	}
 	if (session_find(newname) != NULL) {
 		cmdq_error(item, "duplicate session: %s", newname);
 		free(newname);

session.c

@@ -122,7 +122,6 @@ session_create(const char *prefix, const char *name, const char *cwd,
 
 	s->cwd = xstrdup(cwd);
 
-	s->curw = NULL;
 	TAILQ_INIT(&s->lastw);
 	RB_INIT(&s->windows);
 
@@ -141,7 +140,6 @@ session_create(const char *prefix, const char *name, const char *cwd,
 		s->name = xstrdup(name);
 		s->id = next_session_id++;
 	} else {
-		s->name = NULL;
 		do {
 			s->id = next_session_id++;
 			free(s->name);
@@ -231,11 +229,20 @@ session_destroy(struct session *s, int notify, const char *from)
 	session_remove_ref(s, __func__);
 }
 
-/* Check a session name is valid: not empty and no colons or periods. */
-int
+/* Sanitize session name. */
+char *
 session_check_name(const char *name)
 {
-	return (*name != '\0' && name[strcspn(name, ":.")] == '\0');
+	char	*copy, *cp, *new_name;
+
+	copy = xstrdup(name);
+	for (cp = copy; *cp != '\0'; cp++) {
+		if (*cp == ':' || *cp == '.')
+			*cp = '_';
+	}
+	utf8_stravis(&new_name, copy, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);
+	free(copy);
+	return (new_name);
 }
 
 /* Lock session if it has timed out. */
@@ -555,6 +562,7 @@ session_group_remove(struct session *s)
 	TAILQ_REMOVE(&sg->sessions, s, gentry);
 	if (TAILQ_EMPTY(&sg->sessions)) {
 		RB_REMOVE(session_groups, &session_groups, sg);
+		free((void *)sg->name);
 		free(sg);
 	}
 }

tmux.h

@@ -2722,7 +2722,7 @@ struct session	*session_create(const char *, const char *, const char *,
 void		 session_destroy(struct session *, int,  const char *);
 void		 session_add_ref(struct session *, const char *);
 void		 session_remove_ref(struct session *, const char *);
-int		 session_check_name(const char *);
+char		*session_check_name(const char *);
 void		 session_update_activity(struct session *, struct timeval *);
 struct session	*session_next_session(struct session *);
 struct session	*session_previous_session(struct session *);