[PATCH v7 11/17] KEYS: Introduce link restriction for machine keys
From: Eric Snowberg <eric.snowberg@oracle.com>
Date: 2021-11-16 00:20:07
Also in:
keyrings, linux-efi, linux-integrity, linux-security-module, lkml
Subsystem:
certificate handling, keys/keyrings, the rest · Maintainers:
David Howells, David Woodhouse, Jarkko Sakkinen, Linus Torvalds
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@linux.ibm.com>
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
---
v3: Initial version
v4: moved code under CONFIG_INTEGRITY_MOK_KEYRING
v5: Rename to machine keyring
v6: Change subject name (suggested by Mimi)
Rename restrict_link_by_builtin_secondary_and_ca_trusted
to restrict_link_by_builtin_secondary_and_machine (suggested by
Mimi)
v7: Unmodified from v6
---
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 bc7e44fc82c2..71a00add9805 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_machine + * + * 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 /*
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 98c9b10cdc17..2419a735420f 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_machine( + 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_machine restrict_link_by_builtin_trusted static inline void __init set_machine_trusted_keys(struct key *keyring) { }
--
2.18.4