diff mbox series

[v8,04/17] integrity: Do not allow machine keyring updates following init

Message ID 20211124044124.998170-5-eric.snowberg@oracle.com (mailing list archive)
State Not Applicable
Delegated to: Herbert Xu
Headers show
Series Enroll kernel keys thru MOK | expand

Commit Message

Eric Snowberg Nov. 24, 2021, 4:41 a.m. UTC 
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(-)

Comments

Jarkko Sakkinen Nov. 27, 2021, 12:42 a.m. UTC | #1 
On Tue, 2021-11-23 at 23:41 -0500, Eric Snowberg wrote:
> 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>

For completeness (even if stating the obvious) it would be nice to
say explicitly why no additional keys are not allowed after the init.

/Jarkko
diff mbox series

Patch

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);