core: validate input cgroup path more prudently

(cherry picked from commit efa6ba2ab625aaa160ac435a09e6482fc63bdbe8)
(cherry picked from commit 3cee294fe8cf4fa0eff933ab21416d099942cabd)
(cherry picked from commit 1d22f706bd04f45f8422e17fbde3f56ece17758a)

Origin: backport, https://github.com/systemd/systemd/commit/54588d2dedff54bfb6036670820650e4ea74628f

Gbp-Pq: Name CVE-2026-29111-4.patch

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index b37ed7c8621dac89a0555dc026461c07c43f1653..8385d7ca2a7f3f4e11cb55135799ee3e96594217 100644 (file)
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -549,6 +549,12 @@ static int method_get_unit_by_control_group(sd_bus_message *message, void *userd
         if (r < 0)
                 return r;
 
+        if (!path_is_absolute(cgroup))
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Control group path is not absolute: %s", cgroup);
+
+        if (!path_is_normalized(cgroup))
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Control group path is not normalized: %s", cgroup);
+
         u = manager_get_unit_by_cgroup(m, cgroup);
         if (!u)
                 return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Control group '%s' is not valid or not managed by this instance", cgroup);