Smack: fix another vsscanf out of bounds

[ Upstream commit a6bd4f6d9b07452b0b19842044a6c3ea384b0b88 ]

This is similar to commit 84e99e58e8d1 ("Smack: slab-out-of-bounds in
vsscanf") where we added a bounds check on "rule".

Reported-by: [email protected]
Fixes: f7112e6c9abf ("Smack: allow for significantly longer Smack labels v4")
Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
1 file changed