thunderbolt: Allow clearing the key (e545f0d8) · Commits · 戴 / test

If secure authentication of a devices fails, either because the device already has another key uploaded, or there is some other error sending challenge to the device, and the user only wants to approve the device just once (without a new key being uploaded to the device) the current implementation does not allow this because the key cannot be cleared once set even if we allow it to be changed. Make this scenario possible and allow clearing the key by writing empty string to the key sysfs file. Signed-off-by:

Yehezkel Bernat <yehezkel.bernat@intel.com> Acked-by:

Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-thunderbolt

+2 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,8 @@ Contact: thunderbolt-software@lists.01.org
		Description: When a devices supports Thunderbolt secure connect it will
		have this attribute. Writing 32 byte hex string changes
		authorization to use the secure connection method instead.
		Writing an empty string clears the key and regular connection
		method can be used again.

		What: /sys/bus/thunderbolt/devices/.../device
		Date: Sep 2017

drivers/thunderbolt/switch.c

+11 −4

Original line number	Diff line number	Diff line
		@@ -807,8 +807,11 @@ static ssize_t key_store(struct device dev, struct device_attribute attr,
		struct tb_switch *sw = tb_to_switch(dev);
		u8 key[TB_SWITCH_KEY_SIZE];
		ssize_t ret = count;
		bool clear = false;

		if (hex2bin(key, buf, sizeof(key)))
		if (!strcmp(buf, "\n"))
		clear = true;
		else if (hex2bin(key, buf, sizeof(key)))
		return -EINVAL;

		if (mutex_lock_interruptible(&switch_lock))
		@@ -818,10 +821,14 @@ static ssize_t key_store(struct device dev, struct device_attribute attr,
		ret = -EBUSY;
		} else {
		kfree(sw->key);
		if (clear) {
		sw->key = NULL;
		} else {
		sw->key = kmemdup(key, sizeof(key), GFP_KERNEL);
		if (!sw->key)
		ret = -ENOMEM;
		}
		}

		mutex_unlock(&switch_lock);
		return ret;

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