Hi Mimi,

The kernel can be configured to verify PE signed kernel images, IMA
kernel image signatures, both types of signatures, or none.  This test
verifies only properly signed kernel images are loaded into memory,
based on the kernel configuration and runtime policies.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Reviewed-by: Petr Vorel <pvorel@suse.cz>

...

# SPDX-License-Identifier: GPL-2.0-or-later

+#
+# Loading a kernel image via the kexec_file_load syscall can verify either
+# the IMA signature stored in the security.ima xattr or the PE signature,
+# both signatures depending on the IMA policy, or none.
+#
+# To determine whether the kernel image is signed, this test depends
+# on pesign and getfattr.  This test also requires the kernel to be
+# built with CONFIG_IKCONFIG enabled and either CONFIG_IKCONFIG_PROC
+# enabled or access to the extract-ikconfig script.
+
+VERBOSE=1

Maybe allow to disable verbose without source change?
VERBOSE="${VERBOSE:-1}"

+EXTRACT_IKCONFIG=$(ls /lib/modules/`uname -r`/source/scripts/extract-ikconfig)
+IKCONFIG=/tmp/config-`uname -r`
+PROC_CONFIG="/proc/config.gz"
+KERNEL_IMAGE="/boot/vmlinuz-`uname -r`"
+PESIGN=/usr/bin/pesign
+GETFATTR=/usr/bin/getfattr
+
+TEST="$0"
+. ./common_lib.sh
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+kconfig_enabled()
+{
+	RC=0
+	egrep -q $1 $IKCONFIG
+	if [ $? -eq 0 ]; then
+		RC=1
+	fi
+	return $RC
+}

This would be enough (grep with -e returns only 0 or 1):
kconfig_enabled()
{
	grep -E -q $1 $IKCONFIG
}

+
+# policy rule format: action func=<keyword> [appraise_type=<type>]
+check_ima_policy()
+{
+	IMA_POLICY=/sys/kernel/security/ima/policy
+
+	RC=0
+	if [ $# -eq 3 ]; then
+		grep -e $2 $IMA_POLICY | grep -e "^$1.*$3" 2>&1 >/dev/null
+	else
+		grep -e $2 $IMA_POLICY | grep -e "^$1" 2>&1 >/dev/null
+	fi
+	if [ $? -eq 0 ]; then
+		RC=1
+	fi
+	return $RC
+}

This would be enough and more descriptive:
check_ima_policy()
{
	local action="$1"
	local keyword="$2"
	local type="$3"

	[ -n "$type" ] && type="appraise_type=$type"
	grep -q "^$action.*func=$keyword.*$type" /sys/kernel/security/ima/policy
}

+
+check_kconfig_options()
+{
+	# Attempt to get the kernel config first via proc, and then by
+	# extracting it from the kernel image using scripts/extract-ikconfig.
+	if [ ! -f $PROC_CONFIG ]; then
+		modprobe configs 2>/dev/null
+	fi
+	if [ -f $PROC_CONFIG ]; then
+		cat $PROC_CONFIG > $IKCONFIG
+	fi
+
+	if [ ! -f $IKCONFIG ]; then
+		if [ ! -f $EXTRACT_IKCONFIG ]; then
+			echo "$TEST: requires access to extract-ikconfig" >&2
+			exit $ksft_skip
+		fi
+
+		$EXTRACT_IKCONFIG $KERNEL_IMAGE > $IKCONFIG
+		kconfig_enabled "CONFIG_IKCONFIG=y"
+		if [ $? -eq 0 ]; then
+			echo "$TEST: requires the kernel to be built with CONFIG_IKCONFIG" >&2
+			exit $ksft_skip
+		fi
+	fi
+
+	kconfig_enabled "CONFIG_KEXEC_BZIMAGE_VERIFY_SIG=y"
+	pe_sig_required=$?
+	if [ $VERBOSE -ne 0 ] && [ $pe_sig_required -eq 1 ]; then
+		echo "$TEST: [INFO] PE signed kernel image required"
+	fi

Checks for $VERBOSE here and in other kconfig_enabled usages bellow are a bit
redundant. And you check for assigned variable now and then later on,
you use these variables as global (and reset $ima_sig_required in
check_runtime().

How about using functions instead:
log_info()
{
	echo "$TEST: [INFO] $1"
}
(Reducing some duplicity, IMHO helper functions in shell library used in all
selftest tests would be useful)

kconfig_enabled()
{
	local config="$1"
	local msg="$2"
	local ret

	grep -E -q $config $IKCONFIG
	ret=$?
	[ $VERBOSE -ne 0 ] && [ $ret -eq 1 ] && log_info "$msg"
	return $ret
}

ima_sig_enabled()
{
	kconfig_enabled "CONFIG_KEXEC_BZIMAGE_VERIFY_SIG=y" \
		"PE signed kernel image required"
}

ima_sig_enabled()
{
	kconfig_enabled "CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS=y" \
		"IMA kernel image signature required"
}
Warning is printed each time, but that's deliberate.
If it's not wanted, it can be moved into setup.

...

+check_kconfig_options
+check_for_apps
+check_runtime
+check_for_sigs
+kexec_file_load_test

+rc=$?
+exit $rc

These two are redundant.

Kind regards,
Petr