The mok can not be trusted when the secure boot is disabled. Which
means that the kernel embedded certificate is the only trusted key.
Due to db/dbx are authenticated variables, they needs manufacturer's
KEK for update. So db/dbx are secure when secureboot disabled.
Cc: David Howells <[email protected]>
Cc: Josh Boyer <[email protected]>
Signed-off-by: "Lee, Chun-Yi" <[email protected]>
---
certs/load_uefi.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/certs/load_uefi.c b/certs/load_uefi.c
index 3d88459..d6de4d0 100644
--- a/certs/load_uefi.c
+++ b/certs/load_uefi.c
@@ -164,17 +164,6 @@ static int __init load_uefi_certs(void)
}
}
- mok = get_cert_list(L"MokListRT", &mok_var, &moksize);
- if (!mok) {
- pr_info("MODSIGN: Couldn't get UEFI MokListRT\n");
- } else {
- rc = parse_efi_signature_list("UEFI:MokListRT",
- mok, moksize, get_handler_for_db);
- if (rc)
- pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
- kfree(mok);
- }
-
dbx = get_cert_list(L"dbx", &secure_var, &dbxsize);
if (!dbx) {
pr_info("MODSIGN: Couldn't get UEFI dbx list\n");
@@ -187,6 +176,21 @@ static int __init load_uefi_certs(void)
kfree(dbx);
}
+ /* the MOK can not be trusted when secure boot is disabled */
+ if (!efi_enabled(EFI_SECURE_BOOT))
+ return 0;
+
+ mok = get_cert_list(L"MokListRT", &mok_var, &moksize);
+ if (!mok) {
+ pr_info("MODSIGN: Couldn't get UEFI MokListRT\n");
+ } else {
+ rc = parse_efi_signature_list("UEFI:MokListRT",
+ mok, moksize, get_handler_for_db);
+ if (rc)
+ pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
+ kfree(mok);
+ }
+
return rc;
}
late_initcall(load_uefi_certs);
--
2.10.2
From 1585575101897516324@xxx Fri Dec 01 09:57:31 +0000 2017
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