drm/modes: Introduce a whitelist for the named modes (37641379) · Commits · 戴 / test

The named modes support has introduced a number of glitches that were in part due to the fact that the parser will take any string as a named mode. Since we shouldn't have a lot of options there (and they should be pretty standard), let's introduce a whitelist of the available named modes so that the kernel can differentiate between a poorly formed command line and a named mode. Signed-off-by:

Maxime Ripard <maxime.ripard@bootlin.com> Tested-by:

Thomas Graichen <thomas.graichen@gmail.com> Reviewed-by:

Jernej Skrabec <jernej.skrabec@siol.net> Signed-off-by:

Maxime Ripard <mripard@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190827115850.25731-3-mripard@kernel.org

drivers/gpu/drm/drm_modes.c

+20 −0

Original line number	Diff line number	Diff line
		@@ -1677,6 +1677,22 @@ static int drm_mode_parse_cmdline_options(char *str, size_t len,
		return 0;
		}

		static const char *drm_named_modes_whitelist[] = {
		"NTSC",
		"PAL",
		};

		static bool drm_named_mode_is_in_whitelist(const char *mode, unsigned int size)
		{
		int i;

		for (i = 0; i < ARRAY_SIZE(drm_named_modes_whitelist); i++)
		if (!strncmp(mode, drm_named_modes_whitelist[i], size))
		return true;

		return false;
		}

		/**
		* drm_mode_parse_command_line_for_connector - parse command line modeline for connector
		* @mode_option: optional per connector mode option
		@@ -1794,6 +1810,10 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
		if (named_mode) {
		if (mode_end + 1 > DRM_DISPLAY_MODE_LEN)
		return false;

		if (!drm_named_mode_is_in_whitelist(name, mode_end))
		return false;

		strscpy(mode->name, name, mode_end + 1);
		} else {
		ret = drm_mode_parse_cmdline_res_mode(name, mode_end,

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