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.
Suggested-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Signed-off-by: Eric Snowberg <eric.snowberg@xxxxxxxxxx>
---
v3: Initial version
v4: moved code under CONFIG_INTEGRITY_MOK_KEYRING
v5: Rename to machine keyring
---
certs/system_keyring.c | 23 +++++++++++++++++++++++
include/keys/system_keyring.h | 6 ++++++
2 files changed, 29 insertions(+)
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 08ea542c8096..955bd57815f4 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -99,6 +99,29 @@ void __init set_machine_trusted_keys(struct key *keyring)
{
machine_trusted_keys = keyring;
}
+
+/**
+ * restrict_link_by_builtin_secondary_and_ca_trusted
+ *
+ * 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_ca_trusted(
+ 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
/*
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 98c9b10cdc17..fe4be10e66ef 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -39,8 +39,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
#endif
#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
+extern int restrict_link_by_builtin_secondary_and_ca_trusted(
+ struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restrict_key);
extern void __init set_machine_trusted_keys(struct key *keyring);
#else
+#define restrict_link_by_builtin_secondary_and_ca_trusted restrict_link_by_builtin_trusted
static inline void __init set_machine_trusted_keys(struct key *keyring)
{
}
--
2.18.4
