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PM: hibernate: don't use early_lookup_bdev in resume_store

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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: 421a5fa1a6 ("PM / hibernate: use name_to_dev_t to parse resume")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-22-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2023-05-31 14:55:32 +02:00 committed by Jens Axboe
parent 7a126d5bf9
commit 1e8c813b08
1 changed files with 17 additions and 1 deletions
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18
kernel/power/hibernate.c
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@ -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;