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authorEric Snowberg <eric.snowberg@oracle.com>2022-01-25 21:58:31 -0500
committerJarkko Sakkinen <jarkko@kernel.org>2022-03-08 13:55:52 +0200
commit087aa4ed379054951cb3c8ccaa0c4dbafd903c01 (patch)
tree047426a773b2102dbb56ff42f866683665ca56c1 /certs/system_keyring.c
parent56edb6c25f11f25df153f4804f2d5bced2b49a9e (diff)
KEYS: Introduce link restriction for machine keys
Introduce a new link restriction that includes the trusted builtin, secondary and machine keys. The restriction is based on the key to be added being vouched for by a key in any of these three keyrings. With the introduction of the machine keyring, the end-user may choose to trust Machine Owner Keys (MOK) within the kernel. If they have chosen to trust them, the .machine keyring will contain these keys. If not, the machine keyring will always be empty. Update the restriction check to allow the secondary trusted keyring to also trust machine keys. Allow the .machine keyring to be linked to the secondary_trusted_keys. After the link is created, keys contained in the .machine keyring will automatically be searched when searching secondary_trusted_keys. Suggested-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'certs/system_keyring.c')
-rw-r--r--certs/system_keyring.c35
1 files changed, 34 insertions, 1 deletions
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 08ea542c8096..05b66ce9d1c9 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -89,7 +89,10 @@ static __init struct key_restriction *get_builtin_and_secondary_restriction(void
if (!restriction)
panic("Can't allocate secondary trusted keyring restriction\n");
- restriction->check = restrict_link_by_builtin_and_secondary_trusted;
+ if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
+ restriction->check = restrict_link_by_builtin_secondary_and_machine;
+ else
+ restriction->check = restrict_link_by_builtin_and_secondary_trusted;
return restriction;
}
@@ -98,6 +101,36 @@ static __init struct key_restriction *get_builtin_and_secondary_restriction(void
void __init set_machine_trusted_keys(struct key *keyring)
{
machine_trusted_keys = keyring;
+
+ if (key_link(secondary_trusted_keys, machine_trusted_keys) < 0)
+ panic("Can't link (machine) trusted keyrings\n");
+}
+
+/**
+ * restrict_link_by_builtin_secondary_and_machine - Restrict keyring addition.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restrict_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in, the secondary, or
+ * the machine keyrings.
+ */
+int restrict_link_by_builtin_secondary_and_machine(
+ struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restrict_key)
+{
+ if (machine_trusted_keys && type == &key_type_keyring &&
+ dest_keyring == secondary_trusted_keys &&
+ payload == &machine_trusted_keys->payload)
+ /* Allow the machine keyring to be added to the secondary */
+ return 0;
+
+ return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
+ payload, restrict_key);
}
#endif