[PATCH AUTOSEL 4.14 13/46] dm integrity: fail early if required HMAC key is not available

[Sasha Levin]

From: Milan Broz <gmazyland@xxxxxxxxx>

[ Upstream commit e16b4f99f0f79682a7efe191a8ce694d87ca9fc8 ]

Since crypto API commit 9fa68f62004 ("crypto: hash - prevent using keyed
hashes without setting key") dm-integrity cannot use keyed algorithms
without the key being set.

The dm-integrity recognizes this too late (during use of HMAC), so it
allows creation and formatting of superblock, but the device is in fact
unusable.

Fix it by detecting the key requirement in integrity table constructor.

Signed-off-by: Milan Broz <gmazyland@xxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/dm-integrity.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 898286ed47a1..b10e4c5641ea 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -2547,6 +2547,9 @@ static int get_mac(struct crypto_shash **hash, struct alg_spec *a, char **error,
 				*error = error_key;
 				return r;
 			}
+		} else if (crypto_shash_get_flags(*hash) & CRYPTO_TFM_NEED_KEY) {
+			*error = error_key;
+			return -ENOKEY;
 		}
 	}
 
-- 
2.17.1