selftests/kexec: update get_secureboot_mode

The get_secureboot_mode() function unnecessarily requires both
CONFIG_EFIVAR_FS and CONFIG_EFI_VARS to be enabled to determine if the
system is booted in secure boot mode.  On some systems the old EFI
variable support is not enabled or, possibly, even implemented.

This patch first checks the efivars filesystem for the SecureBoot and
SetupMode flags, but falls back to using the old EFI variable support.

The "secure_boot_file" and "setup_mode_file" couldn't be quoted due to
globbing.  This patch also removes the globbing.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/kexec/kexec_common_lib.sh

@@ -35,41 +35,87 @@ log_skip()
 }
 
 # Check efivar SecureBoot-$(the UUID) and SetupMode-$(the UUID).
-# The secure boot mode can be accessed either as the last integer
-# of "od -An -t u1 /sys/firmware/efi/efivars/SecureBoot-*" or from
-# "od -An -t u1 /sys/firmware/efi/vars/SecureBoot-*/data".  The efi
-# SetupMode can be similarly accessed.
-# Return 1 for SecureBoot mode enabled and SetupMode mode disabled.
-get_secureboot_mode()
+# (Based on kdump-lib.sh)
+get_efivarfs_secureboot_mode()
 {
 	local efivarfs="/sys/firmware/efi/efivars"
-	local secure_boot_file="$efivarfs/../vars/SecureBoot-*/data"
-	local setup_mode_file="$efivarfs/../vars/SetupMode-*/data"
+	local secure_boot_file=""
+	local setup_mode_file=""
 	local secureboot_mode=0
 	local setup_mode=0
 
-	# Make sure that efivars is mounted in the normal location
+	# Make sure that efivar_fs is mounted in the normal location
 	if ! grep -q "^\S\+ $efivarfs efivarfs" /proc/mounts; then
-		log_skip "efivars is not mounted on $efivarfs"
+		log_info "efivars is not mounted on $efivarfs"
+		return 0;
 	fi
+	secure_boot_file=$(find "$efivarfs" -name SecureBoot-* 2>/dev/null)
+	setup_mode_file=$(find "$efivarfs" -name SetupMode-* 2>/dev/null)
+	if [ -f "$secure_boot_file" ] && [ -f "$setup_mode_file" ]; then
+		secureboot_mode=$(hexdump -v -e '/1 "%d\ "' \
+			"$secure_boot_file"|cut -d' ' -f 5)
+		setup_mode=$(hexdump -v -e '/1 "%d\ "' \
+			"$setup_mode_file"|cut -d' ' -f 5)
 
-	# Due to globbing, quoting "secure_boot_file" and "setup_mode_file"
-	# is not possible.  (Todo: initialize variables using find or ls.)
-	if [ ! -e $secure_boot_file ] || [ ! -e $setup_mode_file ]; then
-		log_skip "unknown secureboot/setup mode"
+		if [ $secureboot_mode -eq 1 ] && [ $setup_mode -eq 0 ]; then
+			log_info "secure boot mode enabled (CONFIG_EFIVAR_FS)"
+			return 1;
+		fi
 	fi
+	return 0;
+}
 
-	secureboot_mode=`od -An -t u1 $secure_boot_file`
-	setup_mode=`od -An -t u1 $setup_mode_file`
+get_efi_var_secureboot_mode()
+{
+	local efi_vars
+	local secure_boot_file
+	local setup_mode_file
+	local secureboot_mode
+	local setup_mode
+
+	if [ ! -d "$efi_vars" ]; then
+		log_skip "efi_vars is not enabled\n"
+	fi
+	secure_boot_file=$(find "$efi_vars" -name SecureBoot-* 2>/dev/null)
+	setup_mode_file=$(find "$efi_vars" -name SetupMode-* 2>/dev/null)
+	if [ -f "$secure_boot_file/data" ] && \
+	   [ -f "$setup_mode_file/data" ]; then
+		secureboot_mode=`od -An -t u1 "$secure_boot_file/data"`
+		setup_mode=`od -An -t u1 "$setup_mode_file/data"`
 
 		if [ $secureboot_mode -eq 1 ] && [ $setup_mode -eq 0 ]; then
-		log_info "secure boot mode enabled"
+			log_info "secure boot mode enabled (CONFIG_EFI_VARS)"
 			return 1;
 		fi
-	log_info "secure boot mode not enabled"
+	fi
 	return 0;
 }
 
+# Check efivar SecureBoot-$(the UUID) and SetupMode-$(the UUID).
+# The secure boot mode can be accessed either as the last integer
+# of "od -An -t u1 /sys/firmware/efi/efivars/SecureBoot-*" or from
+# "od -An -t u1 /sys/firmware/efi/vars/SecureBoot-*/data".  The efi
+# SetupMode can be similarly accessed.
+# Return 1 for SecureBoot mode enabled and SetupMode mode disabled.
+get_secureboot_mode()
+{
+	local secureboot_mode=0
+
+	get_efivarfs_secureboot_mode
+	secureboot_mode=$?
+
+	# fallback to using the efi_var files
+	if [ $secureboot_mode -eq 0 ]; then
+		get_efi_var_secureboot_mode
+		secureboot_mode=$?
+	fi
+
+	if [ $secureboot_mode -eq 0 ]; then
+		log_info "secure boot mode not enabled"
+	fi
+	return $secureboot_mode;
+}
+
 require_root_privileges()
 {
 	if [ $(id -ru) -ne 0 ]; then