early_lookup_bdev is supposed to only be called from the early boot
code, but mdtblock_early_get_bdev is called as a general fallback when
lookup_bdev fails, which is problematic because early_lookup_bdev
bypasses all normal path based permission checking, and might cause
problems with certain container environments renaming devices.
Switch to only call early_lookup_bdev when block2mtd is built-in and the
system state in not running yet.
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.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20230531125535.676098-24-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kfree(dev);
}
-static struct block_device *mdtblock_early_get_bdev(const char *devname,
+/*
+ * This function is marked __ref because it calls the __init marked
+ * early_lookup_bdev when called from the early boot code.
+ */
+static struct block_device __ref *mdtblock_early_get_bdev(const char *devname,
fmode_t mode, int timeout, struct block2mtd_dev *dev)
{
struct block_device *bdev = ERR_PTR(-ENODEV);
int i;
/*
+ * We can't use early_lookup_bdev from a running system.
+ */
+ if (system_state >= SYSTEM_RUNNING)
+ return bdev;
+
+ /*
* We might not have the root device mounted at this point.
* Try to resolve the device name by other means.
*/