| From 9f1958a0cc911e1f79b2733ee5029dbd819ff328 Mon Sep 17 00:00:00 2001 |
| From: Josh Boyer <jwboyer@fedoraproject.org> |
| Date: Fri, 5 May 2017 08:21:59 +0100 |
| Subject: [PATCH 4/4] MODSIGN: Allow the "db" UEFI variable to be suppressed |
| |
| If a user tells shim to not use the certs/hashes in the UEFI db variable |
| for verification purposes, shim will set a UEFI variable called |
| MokIgnoreDB. Have the uefi import code look for this and ignore the db |
| variable if it is found. |
| |
| Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> |
| Signed-off-by: David Howells <dhowells@redhat.com> |
| |
| certs/load_uefi.c | 44 ++++++++++++++++++++++++++++++++++---------- |
| 1 file changed, 34 insertions(+), 10 deletions(-) |
| |
| diff --git a/certs/load_uefi.c b/certs/load_uefi.c |
| index b44e464..3d88459 100644 |
| |
| |
| @@ -13,6 +13,26 @@ static __initdata efi_guid_t efi_cert_x509_sha256_guid = EFI_CERT_X509_SHA256_GU |
| static __initdata efi_guid_t efi_cert_sha256_guid = EFI_CERT_SHA256_GUID; |
| |
| /* |
| + * Look to see if a UEFI variable called MokIgnoreDB exists and return true if |
| + * it does. |
| + * |
| + * This UEFI variable is set by the shim if a user tells the shim to not use |
| + * the certs/hashes in the UEFI db variable for verification purposes. If it |
| + * is set, we should ignore the db variable also and the true return indicates |
| + * this. |
| + */ |
| +static __init bool uefi_check_ignore_db(void) |
| +{ |
| + efi_status_t status; |
| + unsigned int db = 0; |
| + unsigned long size = sizeof(db); |
| + efi_guid_t guid = EFI_SHIM_LOCK_GUID; |
| + |
| + status = efi.get_variable(L"MokIgnoreDB", &guid, NULL, &size, &db); |
| + return status == EFI_SUCCESS; |
| +} |
| + |
| +/* |
| * Get a certificate list blob from the named EFI variable. |
| */ |
| static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid, |
| @@ -113,7 +133,9 @@ static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_ty |
| } |
| |
| /* |
| - * Load the certs contained in the UEFI databases |
| + * Load the certs contained in the UEFI databases into the secondary trusted |
| + * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist |
| + * keyring. |
| */ |
| static int __init load_uefi_certs(void) |
| { |
| @@ -129,15 +151,17 @@ static int __init load_uefi_certs(void) |
| /* Get db, MokListRT, and dbx. They might not exist, so it isn't |
| * an error if we can't get them. |
| */ |
| - db = get_cert_list(L"db", &secure_var, &dbsize); |
| - if (!db) { |
| - pr_err("MODSIGN: Couldn't get UEFI db list\n"); |
| - } else { |
| - rc = parse_efi_signature_list("UEFI:db", |
| - db, dbsize, get_handler_for_db); |
| - if (rc) |
| - pr_err("Couldn't parse db signatures: %d\n", rc); |
| - kfree(db); |
| + if (!uefi_check_ignore_db()) { |
| + db = get_cert_list(L"db", &secure_var, &dbsize); |
| + if (!db) { |
| + pr_err("MODSIGN: Couldn't get UEFI db list\n"); |
| + } else { |
| + rc = parse_efi_signature_list("UEFI:db", |
| + db, dbsize, get_handler_for_db); |
| + if (rc) |
| + pr_err("Couldn't parse db signatures: %d\n", rc); |
| + kfree(db); |
| + } |
| } |
| |
| mok = get_cert_list(L"MokListRT", &mok_var, &moksize); |
| -- |
| 2.9.3 |
| |