[PATCH 2/2] efi: show error messages only when loading certificates is failed

["Lee, Chun-Yi" <joeyli.kernel@xxxxxxxxx>]

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.

Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
---
 security/integrity/platform_certs/load_uefi.c | 41 ++++++++++++++-------------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index 81b19c52832b..3b766831d2c5 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 +49,31 @@ 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 (0x%lx)\n",
+		source, efi_status_to_str(status), status);
+	return NULL;
 }
 
 /*
@@ -153,10 +162,8 @@ 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 +173,8 @@ 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 +182,8 @@ 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