Commit 1e8c813b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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PM: hibernate: don't use early_lookup_bdev in resume_store 



resume_store is a sysfs attribute written during normal kernel runtime,
and it should not use the early_lookup_bdev API that bypasses all normal
path based permission checking, and might cause problems with certain
container environments renaming devices.

Switch to lookup_bdev, which does a normal path lookup instead, and fall
back to trying to parse a numeric dev_t just like early_lookup_bdev did.

Note that this strictly speaking changes the kernel ABI as the PARTUUID=
and PARTLABEL= style syntax is now not available during a running
systems.  They never were intended for that, but this breaks things
we'll have to figure out a way to make them available again.  But if
avoidable in any way I'd rather avoid that.

Fixes: 421a5fa1 ("PM / hibernate: use name_to_dev_t to parse resume")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarRafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-22-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7a126d5b

kernel/power/hibernate.c

+17 −1
Original line number Diff line number Diff line
@@ -1178,7 +1178,23 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr, 
	if (!name)

		return -ENOMEM;



	error = early_lookup_bdev(name, &dev);

	error = lookup_bdev(name, &dev);

	if (error) {

		unsigned maj, min, offset;

		char *p, dummy;



		if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||

		    sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset,

				&dummy) == 3) {

			dev = MKDEV(maj, min);

			if (maj != MAJOR(dev) || min != MINOR(dev))

				error = -EINVAL;

		} else {

			dev = new_decode_dev(simple_strtoul(name, &p, 16));

			if (*p)

				error = -EINVAL;

		}

	}

	kfree(name);

	if (error)

		return error;