From 22ff1a362df262dcc56ce282d9d658350c1fc036 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 20 Jul 2017 18:00:51 +0200 Subject: platform/x86: alienware-wmi: fix format string overflow warning gcc points out a possible format string overflow for a large value of 'zone': drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init': drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=] sprintf(buffer, "zone%02X", i); ^~~~ drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646] sprintf(buffer, "zone%02X", i); ^~~~~~~~~~ drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10 This replaces the 'int' variable with an 'u8' to make sure it always fits, renaming the variable to 'zone' for clarity. Unfortunately, gcc-7.1.1 still warns about it with that change, which seems to be unintended by the gcc developers. I have opened a bug against gcc with a reduced test case. As a workaround, I also change the format string to use "%02hhX", which shuts up the warning in that version. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81483 Link: https://patchwork.ozlabs.org/patch/788415/ Suggested-by: Andy Shevchenko Signed-off-by: Arnd Bergmann [andy: added empty lines after u8 zone; definitions] Signed-off-by: Andy Shevchenko --- drivers/platform/x86/alienware-wmi.c | 40 +++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 19 deletions(-) (limited to 'drivers/platform') diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c index 0831b428c217..4eb8e1a472b2 100644 --- a/drivers/platform/x86/alienware-wmi.c +++ b/drivers/platform/x86/alienware-wmi.c @@ -255,12 +255,13 @@ static int parse_rgb(const char *buf, struct platform_zone *zone) static struct platform_zone *match_zone(struct device_attribute *attr) { - int i; - for (i = 0; i < quirks->num_zones; i++) { - if ((struct device_attribute *)zone_data[i].attr == attr) { + u8 zone; + + for (zone = 0; zone < quirks->num_zones; zone++) { + if ((struct device_attribute *)zone_data[zone].attr == attr) { pr_debug("alienware-wmi: matched zone location: %d\n", - zone_data[i].location); - return &zone_data[i]; + zone_data[zone].location); + return &zone_data[zone]; } } return NULL; @@ -420,7 +421,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, show_control_state, static int alienware_zone_init(struct platform_device *dev) { - int i; + u8 zone; char buffer[10]; char *name; @@ -457,19 +458,19 @@ static int alienware_zone_init(struct platform_device *dev) if (!zone_data) return -ENOMEM; - for (i = 0; i < quirks->num_zones; i++) { - sprintf(buffer, "zone%02X", i); + for (zone = 0; zone < quirks->num_zones; zone++) { + sprintf(buffer, "zone%02hhX", zone); name = kstrdup(buffer, GFP_KERNEL); if (name == NULL) return 1; - sysfs_attr_init(&zone_dev_attrs[i].attr); - zone_dev_attrs[i].attr.name = name; - zone_dev_attrs[i].attr.mode = 0644; - zone_dev_attrs[i].show = zone_show; - zone_dev_attrs[i].store = zone_set; - zone_data[i].location = i; - zone_attrs[i] = &zone_dev_attrs[i].attr; - zone_data[i].attr = &zone_dev_attrs[i]; + sysfs_attr_init(&zone_dev_attrs[zone].attr); + zone_dev_attrs[zone].attr.name = name; + zone_dev_attrs[zone].attr.mode = 0644; + zone_dev_attrs[zone].show = zone_show; + zone_dev_attrs[zone].store = zone_set; + zone_data[zone].location = zone; + zone_attrs[zone] = &zone_dev_attrs[zone].attr; + zone_data[zone].attr = &zone_dev_attrs[zone]; } zone_attrs[quirks->num_zones] = &dev_attr_lighting_control_state.attr; zone_attribute_group.attrs = zone_attrs; @@ -481,12 +482,13 @@ static int alienware_zone_init(struct platform_device *dev) static void alienware_zone_exit(struct platform_device *dev) { + u8 zone; + sysfs_remove_group(&dev->dev.kobj, &zone_attribute_group); led_classdev_unregister(&global_led); if (zone_dev_attrs) { - int i; - for (i = 0; i < quirks->num_zones; i++) - kfree(zone_dev_attrs[i].attr.name); + for (zone = 0; zone < quirks->num_zones; zone++) + kfree(zone_dev_attrs[zone].attr.name); } kfree(zone_dev_attrs); kfree(zone_data); -- cgit v1.2.3