1 files changed, 93 insertions, 2 deletions

diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index 6b1ac5f5896a..86292965f493 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -17,9 +17,12 @@ static struct asymmetric_key_id *ca_keyid;
 
 #ifndef MODULE
 static struct {
-	struct asymmetric_key_id id;
-	unsigned char data[10];
+	/* Must be last as it ends in a flexible-array member. */
+	TRAILING_OVERLAP(struct asymmetric_key_id, id, data,
+		unsigned char data[10];
+	);
 } cakey;
+static_assert(offsetof(typeof(cakey), id.data) == offsetof(typeof(cakey), data));
 
 static int __init ca_keys_setup(char *str)
 {
@@ -102,12 +105,100 @@ int restrict_link_by_signature(struct key *dest_keyring,
 
 	if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
 		ret = -ENOKEY;
+	else if (IS_BUILTIN(CONFIG_SECONDARY_TRUSTED_KEYRING_SIGNED_BY_BUILTIN) &&
+		 !strcmp(dest_keyring->description, ".secondary_trusted_keys") &&
+		 !test_bit(KEY_FLAG_BUILTIN, &key->flags))
+		ret = -ENOKEY;
 	else
 		ret = verify_signature(key, sig);
 	key_put(key);
 	return ret;
 }
 
+/**
+ * restrict_link_by_ca - Restrict additions to a ring of CA keys
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @trust_keyring: Unused.
+ *
+ * Check if the new certificate is a CA. If it is a CA, then mark the new
+ * certificate as being ok to link.
+ *
+ * Returns 0 if the new certificate was accepted, -ENOKEY if the
+ * certificate is not a CA. -ENOPKG if the signature uses unsupported
+ * crypto, or some other error if there is a matching certificate but
+ * the signature check cannot be performed.
+ */
+int restrict_link_by_ca(struct key *dest_keyring,
+			const struct key_type *type,
+			const union key_payload *payload,
+			struct key *trust_keyring)
+{
+	const struct public_key *pkey;
+
+	if (type != &key_type_asymmetric)
+		return -EOPNOTSUPP;
+
+	pkey = payload->data[asym_crypto];
+	if (!pkey)
+		return -ENOPKG;
+	if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
+		return -ENOKEY;
+	if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
+		return -ENOKEY;
+	if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX))
+		return 0;
+	if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
+		return -ENOKEY;
+
+	return 0;
+}
+
+/**
+ * restrict_link_by_digsig - Restrict additions to a ring of digsig keys
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Check if the new certificate has digitalSignature usage set. If it is,
+ * then mark the new certificate as being ok to link. Afterwards verify
+ * the new certificate against the ones in the trust_keyring.
+ *
+ * Returns 0 if the new certificate was accepted, -ENOKEY if the
+ * certificate is not a digsig. -ENOPKG if the signature uses unsupported
+ * crypto, or some other error if there is a matching certificate but
+ * the signature check cannot be performed.
+ */
+int restrict_link_by_digsig(struct key *dest_keyring,
+			    const struct key_type *type,
+			    const union key_payload *payload,
+			    struct key *trust_keyring)
+{
+	const struct public_key *pkey;
+
+	if (type != &key_type_asymmetric)
+		return -EOPNOTSUPP;
+
+	pkey = payload->data[asym_crypto];
+
+	if (!pkey)
+		return -ENOPKG;
+
+	if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
+		return -ENOKEY;
+
+	if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
+		return -ENOKEY;
+
+	if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
+		return -ENOKEY;
+
+	return restrict_link_by_signature(dest_keyring, type, payload,
+					  trust_keyring);
+}
+
 static bool match_either_id(const struct asymmetric_key_id **pair,
 			    const struct asymmetric_key_id *single)
 {