Commit 81ca2dbe authored Jun 03, 2023 by Demi Marie Obenour Committed by Mike Snitzer Jun 23, 2023

dm ioctl: Refuse to create device named "." or ".."

Using either of these is going to greatly confuse userspace, as they are
not valid symlink names and so creating the usual /dev/mapper/NAME
symlink will not be possible. As creating a device with either of these
names is almost certainly a userspace bug, just error out.

Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

parent a85f1a9d

drivers/md/dm-ioctl.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -771,8 +771,10 @@ static int check_name(const char *name)
		return -EINVAL;
		}

		if (strcmp(name, DM_CONTROL_NODE) == 0) {
		DMERR("device name cannot be \"%s\"", DM_CONTROL_NODE);
		if (strcmp(name, DM_CONTROL_NODE) == 0 \|\|
		strcmp(name, ".") == 0 \|\|
		strcmp(name, "..") == 0) {
		DMERR("device name cannot be \"%s\", \".\", or \"..\"", DM_CONTROL_NODE);
		return -EINVAL;
		}