From 3764137906a5acece8b5546873a70b1e6263a1a6 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Tue, 27 Aug 2019 13:58:49 +0200 Subject: [PATCH] drm/modes: Introduce a whitelist for the named modes 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 Tested-by: Thomas Graichen Reviewed-by: Jernej Skrabec Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20190827115850.25731-3-mripard@kernel.org --- drivers/gpu/drm/drm_modes.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c index 27fe410..0d23bf72 100644 --- a/drivers/gpu/drm/drm_modes.c +++ b/drivers/gpu/drm/drm_modes.c @@ -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, -- 2.7.4