gpu: drm: drm_dp_mst_topology.c: Fix improper use of strncat

Fixed wrong usage of strncat, switched to strlcpy.
While sending the string size to function to reduce
the potential for misuse in future.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index b3adf14..094af1d 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -995,19 +995,20 @@ static void drm_dp_check_port_guid(struct drm_dp_mst_branch *mstb,
 
 static void build_mst_prop_path(struct drm_dp_mst_port *port,
                                struct drm_dp_mst_branch *mstb,
-                               char *proppath)
+                               char *proppath,
+                               size_t proppath_size)
 {
        int i;
        char temp[8];
-       snprintf(proppath, 255, "mst:%d", mstb->mgr->conn_base_id);
+       snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
        for (i = 0; i < (mstb->lct - 1); i++) {
                int shift = (i % 2) ? 0 : 4;
                int port_num = mstb->rad[i / 2] >> shift;
-               snprintf(temp, 8, "-%d", port_num);
-               strncat(proppath, temp, 255);
+               snprintf(temp, sizeof(temp), "-%d", port_num);
+               strlcat(proppath, temp, proppath_size);
        }
-       snprintf(temp, 8, "-%d", port->port_num);
-       strncat(proppath, temp, 255);
+       snprintf(temp, sizeof(temp), "-%d", port->port_num);
+       strlcat(proppath, temp, proppath_size);
 }
 
 static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
@@ -1078,7 +1079,7 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
 
        if (created && !port->input) {
                char proppath[255];
-               build_mst_prop_path(port, mstb, proppath);
+               build_mst_prop_path(port, mstb, proppath, sizeof(proppath));
                port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
        }