[PATCH] KEYS: Print digitalSignature and CA link errors

[Kevin Bowling <kevin.bowling@xxxxxxxxxx>]

ENOKEY is overloaded for several different failure types in these link
functions.  In addition, by the time we are consuming the return several
other methods can return ENOKEY.  Add some error prints to help diagnose
fundamental certificate issues.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kevin Bowling <kevin.bowling@xxxxxxxxxx>
---
 crypto/asymmetric_keys/restrict.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index afcd4d101ac5..472561e451b3 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -140,14 +140,20 @@ int restrict_link_by_ca(struct key *dest_keyring,
 	pkey = payload->data[asym_crypto];
 	if (!pkey)
 		return -ENOPKG;
-	if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
+	if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags)) {
+		pr_err("Missing CA usage bit\n");
 		return -ENOKEY;
-	if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
+	}
+	if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags)) {
+		pr_err("Missing keyCertSign usage bit\n");
 		return -ENOKEY;
+	}
 	if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX))
 		return 0;
-	if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
+	if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags)) {
+		pr_err("Unexpected digitalSignature usage bit\n");
 		return -ENOKEY;
+	}
 
 	return 0;
 }
@@ -183,14 +189,20 @@ int restrict_link_by_digsig(struct key *dest_keyring,
 	if (!pkey)
 		return -ENOPKG;
 
-	if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
+	if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags)) {
+		pr_err("Missing digitalSignature usage bit\n");
 		return -ENOKEY;
+	}
 
-	if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
+	if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags)) {
+		pr_err("Unexpected CA usage bit\n");
 		return -ENOKEY;
+	}
 
-	if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
+	if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags)) {
+		pr_err("Unexpected keyCertSign usage bit\n");
 		return -ENOKEY;
+	}
 
 	return restrict_link_by_signature(dest_keyring, type, payload,
 					  trust_keyring);
-- 
2.46.0