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authorLee, Chun-Yi2021-12-18 10:09:05 +0800
committerMimi Zohar2021-12-24 10:25:24 -0500
commit92ad19559ea9a8ec6f158480934ae26ebfe2c14f (patch)
tree7cab118eacabaecc222cbc63040de48a016005ee
parent54bf7fa3efd08eea03e4bac04e188ee3db6173a7 (diff)
integrity: Do not load MOK and MOKx when secure boot be disabled
The security of Machine Owner Key (MOK) relies on secure boot. When secure boot is disabled, EFI firmware will not verify binary code. Then arbitrary efi binary code can modify MOK when rebooting. This patch prevents MOK/MOKx be loaded when secure boot be disabled. Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com> Reviewed-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
-rw-r--r--security/integrity/platform_certs/load_uefi.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index f290f78c3f30..08b6d12f99b4 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -6,6 +6,7 @@
#include <linux/err.h>
#include <linux/efi.h>
#include <linux/slab.h>
+#include <linux/ima.h>
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include "../integrity.h"
@@ -176,6 +177,10 @@ static int __init load_uefi_certs(void)
kfree(dbx);
}
+ /* the MOK/MOKx can not be trusted when secure boot is disabled */
+ if (!arch_ima_get_secureboot())
+ return 0;
+
mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status);
if (!mokx) {
if (status == EFI_NOT_FOUND)