On Fri, 13 Dec 2019 at 10:07, Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx> wrote:
>
> When loading certificates list from EFI variables, the error
> message and efi status code always be emitted to dmesg. It looks
> ugly:
>
> [ 2.335031] Couldn't get size: 0x800000000000000e
> [ 2.335032] Couldn't get UEFI MokListRT
> [ 2.339985] Couldn't get size: 0x800000000000000e
> [ 2.339987] Couldn't get UEFI dbx list
>
> This cosmetic patch moved the messages to the error handling code
> path. And, it also shows the corresponding status string of status
> code.
>
So what output do we get after applying this patch when those
variables don't exist?
> Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
> ---
> security/integrity/platform_certs/load_uefi.c | 40 ++++++++++++++-------------
> 1 file changed, 21 insertions(+), 19 deletions(-)
>
> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
> index 81b19c52832b..b6c60fb3fb6c 100644
> --- a/security/integrity/platform_certs/load_uefi.c
> +++ b/security/integrity/platform_certs/load_uefi.c
> @@ -1,4 +1,5 @@
> // SPDX-License-Identifier: GPL-2.0
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> #include <linux/kernel.h>
> #include <linux/sched.h>
> @@ -39,7 +40,7 @@ static __init bool uefi_check_ignore_db(void)
> * Get a certificate list blob from the named EFI variable.
> */
> static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
> - unsigned long *size)
> + unsigned long *size, const char *source)
> {
> efi_status_t status;
> unsigned long lsize = 4;
> @@ -48,23 +49,30 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
>
> status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
> if (status != EFI_BUFFER_TOO_SMALL) {
> - pr_err("Couldn't get size: 0x%lx\n", status);
> - return NULL;
> + if (status == EFI_NOT_FOUND) {
> + pr_debug("%s list was not found\n", source);
> + return NULL;
> + }
> + goto err;
> }
>
> db = kmalloc(lsize, GFP_KERNEL);
> - if (!db)
> - return NULL;
> + if (!db) {
> + status = EFI_OUT_OF_RESOURCES;
> + goto err;
> + }
>
> status = efi.get_variable(name, guid, NULL, &lsize, db);
> if (status != EFI_SUCCESS) {
> kfree(db);
> - pr_err("Error reading db var: 0x%lx\n", status);
> - return NULL;
> + goto err;
> }
>
> *size = lsize;
> return db;
> +err:
> + pr_err("Couldn't get %s list: %s\n", source, efi_status_to_str(status));
> + return NULL;
> }
>
> /*
> @@ -153,10 +161,8 @@ static int __init load_uefi_certs(void)
> * an error if we can't get them.
> */
> 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 {
> + db = get_cert_list(L"db", &secure_var, &dbsize, "UEFI:db");
> + if (db) {
> rc = parse_efi_signature_list("UEFI:db",
> db, dbsize, get_handler_for_db);
> if (rc)
> @@ -166,10 +172,8 @@ static int __init load_uefi_certs(void)
> }
> }
>
> - mok = get_cert_list(L"MokListRT", &mok_var, &moksize);
> - if (!mok) {
> - pr_info("Couldn't get UEFI MokListRT\n");
> - } else {
> + mok = get_cert_list(L"MokListRT", &mok_var, &moksize, "UEFI:MokListRT");
> + if (mok) {
> rc = parse_efi_signature_list("UEFI:MokListRT",
> mok, moksize, get_handler_for_db);
> if (rc)
> @@ -177,10 +181,8 @@ static int __init load_uefi_certs(void)
> kfree(mok);
> }
>
> - dbx = get_cert_list(L"dbx", &secure_var, &dbxsize);
> - if (!dbx) {
> - pr_info("Couldn't get UEFI dbx list\n");
> - } else {
> + dbx = get_cert_list(L"dbx", &secure_var, &dbxsize, "UEFI:dbx");
> + if (dbx) {
> rc = parse_efi_signature_list("UEFI:dbx",
> dbx, dbxsize,
> get_handler_for_dbx);
> --
> 2.16.4
>
