drm/display/dp_mst: Replace all non-returning strlcpy with strscpy

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230522155124.2336545-1-azeemshaikh38@gmail.com

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 16565a0..e6a78fd 100644 (file)
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -2103,7 +2103,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
        aux->ddc.owner = THIS_MODULE;
        aux->ddc.dev.parent = aux->dev;
 
-       strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
+       strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
                sizeof(aux->ddc.name));
 
        ret = drm_dp_aux_register_devnode(aux);

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 38dab76..8f74031 100644 (file)
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -5702,7 +5702,7 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
        aux->ddc.dev.parent = parent_dev;
        aux->ddc.dev.of_node = parent_dev->of_node;
 
-       strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
+       strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
                sizeof(aux->ddc.name));
 
        return i2c_add_adapter(&aux->ddc);

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 3fd6c73..6252ac0 100644 (file)
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -223,7 +223,7 @@ mipi_dsi_device_register_full(struct mipi_dsi_host *host,
 
        device_set_node(&dsi->dev, of_fwnode_handle(info->node));
        dsi->channel = info->channel;
-       strlcpy(dsi->name, info->type, sizeof(dsi->name));
+       strscpy(dsi->name, info->type, sizeof(dsi->name));
 
        ret = mipi_dsi_device_add(dsi);
        if (ret) {