[PATCH v8 04/17] integrity: Do not allow machine keyring updates following init
From: Eric Snowberg <eric.snowberg@oracle.com>
Date: 2021-11-24 04:44:05
Also in:
keyrings, linux-crypto, linux-efi, linux-integrity, lkml
Subsystem:
extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
The machine keyring is setup during init. No additional keys should be allowed to be added afterwards. Leave the permission as read only. Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> --- v2: Initial version v4: Unmodified from v2 v5: Rename to machine keyring v6: Add additional comment (suggested by Jarkko) v7: Unmodified from v6 v8: Code unmodified from v7 added Mimi's Reviewed-by --- security/integrity/digsig.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 8c315be8ad99..910fe29a5037 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c@@ -140,7 +140,13 @@ int __init integrity_init_keyring(const unsigned int id) return -ENOMEM; restriction->check = restrict_link_to_ima; - perm |= KEY_USR_WRITE; + + /* + * No additional keys shall be allowed to load into the machine + * keyring following init + */ + if (id != INTEGRITY_KEYRING_MACHINE) + perm |= KEY_USR_WRITE; out: return __integrity_init_keyring(id, perm, restriction);
--
2.18.4