thinkpad-acpi: restrict access to some firmware LEDs (a4d5effc) · Commits · 戴 / test

Documentation/laptops/thinkpad-acpi.txt

+11 −0

Original line number	Diff line number	Diff line
		@@ -901,6 +901,17 @@ some older ThinkPad models, it is possible to query the status of the
		LED indicators as well. Newer ThinkPads cannot query the real status
		of the LED indicators.

		Because misuse of the LEDs could induce an unaware user to perform
		dangerous actions (like undocking or ejecting a bay device while the
		buses are still active), or mask an important alarm (such as a nearly
		empty battery, or a broken battery), access to most LEDs is
		restricted.

		Unrestricted access to all LEDs requires that thinkpad-acpi be
		compiled with the CONFIG_THINKPAD_ACPI_UNSAFE_LEDS option enabled.
		Distributions must never enable this option. Individual users that
		are aware of the consequences are welcome to enabling it.

		procfs notes:

		The available commands are:

drivers/platform/x86/Kconfig

+24 −0

Original line number	Diff line number	Diff line
		@@ -226,6 +226,30 @@ config THINKPAD_ACPI_DEBUG

		If you are not sure, say N here.

		config THINKPAD_ACPI_UNSAFE_LEDS
		bool "Allow control of important LEDs (unsafe)"
		depends on THINKPAD_ACPI
		default n
		---help---
		Overriding LED state on ThinkPads can mask important
		firmware alerts (like critical battery condition), or misled
		the user into damaging the hardware (undocking or ejecting
		the bay while buses are still active), etc.

		LED control on the ThinkPad is write-only (with very few
		exceptions on very ancient models), which makes it
		impossible to know beforehand if important information will
		be lost when one changes LED state.

		Users that know what they are doing can enable this option
		and the driver will allow control of every LED, including
		the ones on the dock stations.

		Never enable this option on a distribution kernel.

		Say N here, unless you are building a kernel for your own
		use, and need to control the important firmware LEDs.

		config THINKPAD_ACPI_DOCK
		bool "Legacy Docking Station Support"
		depends on THINKPAD_ACPI

drivers/platform/x86/thinkpad_acpi.c

+56 −20

Original line number	Diff line number	Diff line
		@@ -4657,6 +4657,16 @@ static const char * const tpacpi_led_names[TPACPI_LED_NUMLEDS] = {
		"tpacpi::unknown_led",
		"tpacpi::standby",
		};
		#define TPACPI_SAFE_LEDS 0x0081U

		static inline bool tpacpi_is_led_restricted(const unsigned int led)
		{
		#ifdef CONFIG_THINKPAD_ACPI_UNSAFE_LEDS
		return false;
		#else
		return (TPACPI_SAFE_LEDS & (1 << led)) == 0;
		#endif
		}

		static int led_get_status(const unsigned int led)
		{
		@@ -4694,16 +4704,20 @@ static int led_set_status(const unsigned int led,
		switch (led_supported) {
		case TPACPI_LED_570:
		/* 570 */
		if (led > 7)
		if (unlikely(led > 7))
		return -EINVAL;
		if (unlikely(tpacpi_is_led_restricted(led)))
		return -EPERM;
		if (!acpi_evalf(led_handle, NULL, NULL, "vdd",
		(1 << led), led_sled_arg1[ledstatus]))
		rc = -EIO;
		break;
		case TPACPI_LED_OLD:
		/* 600e/x, 770e, 770x, A21e, A2xm/p, T20-22, X20 */
		if (led > 7)
		if (unlikely(led > 7))
		return -EINVAL;
		if (unlikely(tpacpi_is_led_restricted(led)))
		return -EPERM;
		rc = ec_write(TPACPI_LED_EC_HLMS, (1 << led));
		if (rc >= 0)
		rc = ec_write(TPACPI_LED_EC_HLBL,
		@@ -4714,6 +4728,10 @@ static int led_set_status(const unsigned int led,
		break;
		case TPACPI_LED_NEW:
		/* all others */
		if (unlikely(led >= TPACPI_LED_NUMLEDS))
		return -EINVAL;
		if (unlikely(tpacpi_is_led_restricted(led)))
		return -EPERM;
		if (!acpi_evalf(led_handle, NULL, NULL, "vdd",
		led, led_led_arg1[ledstatus]))
		rc = -EIO;
		@@ -4806,6 +4824,30 @@ static void led_exit(void)
		kfree(tpacpi_leds);
		}

		static int __init tpacpi_init_led(unsigned int led)
		{
		int rc;

		tpacpi_leds[led].led = led;

		tpacpi_leds[led].led_classdev.brightness_set = &led_sysfs_set;
		tpacpi_leds[led].led_classdev.blink_set = &led_sysfs_blink_set;
		if (led_supported == TPACPI_LED_570)
		tpacpi_leds[led].led_classdev.brightness_get =
		&led_sysfs_get;

		tpacpi_leds[led].led_classdev.name = tpacpi_led_names[led];

		INIT_WORK(&tpacpi_leds[led].work, led_set_status_worker);

		rc = led_classdev_register(&tpacpi_pdev->dev,
		&tpacpi_leds[led].led_classdev);
		if (rc < 0)
		tpacpi_leds[led].led_classdev.name = NULL;

		return rc;
		}

		static int __init led_init(struct ibm_init_struct *iibm)
		{
		unsigned int i;
		@@ -4839,27 +4881,21 @@ static int __init led_init(struct ibm_init_struct *iibm)
		}

		for (i = 0; i < TPACPI_LED_NUMLEDS; i++) {
		tpacpi_leds[i].led = i;

		tpacpi_leds[i].led_classdev.brightness_set = &led_sysfs_set;
		tpacpi_leds[i].led_classdev.blink_set = &led_sysfs_blink_set;
		if (led_supported == TPACPI_LED_570)
		tpacpi_leds[i].led_classdev.brightness_get =
		&led_sysfs_get;

		tpacpi_leds[i].led_classdev.name = tpacpi_led_names[i];

		INIT_WORK(&tpacpi_leds[i].work, led_set_status_worker);

		rc = led_classdev_register(&tpacpi_pdev->dev,
		&tpacpi_leds[i].led_classdev);
		if (!tpacpi_is_led_restricted(i)) {
		rc = tpacpi_init_led(i);
		if (rc < 0) {
		tpacpi_leds[i].led_classdev.name = NULL;
		led_exit();
		return rc;
		}
		}
		}

		#ifdef CONFIG_THINKPAD_ACPI_UNSAFE_LEDS
		if (led_supported != TPACPI_LED_NONE)
		printk(TPACPI_NOTICE
		"warning: userspace override of important "
		"firmware LEDs is enabled\n");
		#endif
		return (led_supported != TPACPI_LED_NONE)? 0 : 1;
		}

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