1 files changed, 13 insertions, 2 deletions

diff --git a/sway/ipc-json.c b/sway/ipc-json.c
index d3731092..1ebc3bd2 100644
--- a/sway/ipc-json.c
+++ b/sway/ipc-json.c
@@ -384,8 +384,19 @@ static json_object *ipc_json_describe_scratchpad_output(void) {
 
 static void ipc_json_describe_workspace(struct sway_workspace *workspace,
                 json_object *object) {
-        int num = isdigit(workspace->name[0]) ? atoi(workspace->name) : -1;
-
+        int num;
+        if (isdigit(workspace->name[0])) {
+                errno = 0;
+                char *endptr = NULL;
+                long long parsed_num = strtoll(workspace->name, &endptr, 10);
+                if (errno != 0 || parsed_num > INT32_MAX || parsed_num < 0 || endptr == workspace->name) {
+                        num = -1;
+                } else {
+                        num = (int) parsed_num;
+                }
+        } else {
+                num = -1;
+        }
         json_object_object_add(object, "num", json_object_new_int(num));
         json_object_object_add(object, "fullscreen_mode", json_object_new_int(1));
         json_object_object_add(object, "output", workspace->output ?