tls: Avoid copying crypto_info again after cipher_type check.

commit 196c31b4b54474b31dee3c30352c45c2a93e9226 upstream.

Avoid copying crypto_info again after cipher_type check
to avoid a TOCTOU exploits.
The temporary array on the stack is removed as we don't really need it

Fixes: 3c4d7559 ('tls: kernel TLS support')
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 4.14: Preserve changes made by earlier backports of
 "tls: return -EBUSY if crypto_info is already set" and "tls: zero the
 crypto information from tls_context before freeing"]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>