From 76adb2fbc69a13c80b39042aab4d34e99309c8d4 Mon Sep 17 00:00:00 2001 From: Eric Snowberg Date: Thu, 2 Mar 2023 11:46:51 -0500 Subject: KEYS: CA link restriction Add a new link restriction. Restrict the addition of keys in a keyring based on the key to be added being a CA. Signed-off-by: Eric Snowberg Reviewed-by: Mimi Zohar Reviewed-by: Jarkko Sakkinen Tested-by: Mimi Zohar Signed-off-by: Jarkko Sakkinen --- crypto/asymmetric_keys/restrict.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'crypto/asymmetric_keys') diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c index 6b1ac5f5896a..48457c6f33f9 100644 --- a/crypto/asymmetric_keys/restrict.c +++ b/crypto/asymmetric_keys/restrict.c @@ -108,6 +108,44 @@ int restrict_link_by_signature(struct key *dest_keyring, 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 (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags)) + return -ENOKEY; + + return 0; +} + static bool match_either_id(const struct asymmetric_key_id **pair, const struct asymmetric_key_id *single) { -- cgit v1.2.3-59-g8ed1b