Merge branch 'for-6.1/sysfs-patched-object' into for-linus

Documentation/ABI/testing/sysfs-kernel-livepatch

@@ -55,6 +55,14 @@ Description:
 		The object directory contains subdirectories for each function
 		that is patched within the object.
 
+What:		/sys/kernel/livepatch/<patch>/<object>/patched
+Date:		August 2022
+KernelVersion:	6.1.0
+Contact:	[email protected]
+Description:
+		An attribute which indicates whether the object is currently
+		patched.
+
 What:		/sys/kernel/livepatch/<patch>/<object>/<function,sympos>
 Date:		Nov 2014
 KernelVersion:	3.19.0

kernel/livepatch/core.c

@@ -325,6 +325,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
  * /sys/kernel/livepatch/<patch>/transition
  * /sys/kernel/livepatch/<patch>/force
  * /sys/kernel/livepatch/<patch>/<object>
+ * /sys/kernel/livepatch/<patch>/<object>/patched
  * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
  */
 static int __klp_disable_patch(struct klp_patch *patch);
@@ -431,6 +432,22 @@ static struct attribute *klp_patch_attrs[] = {
 };
 ATTRIBUTE_GROUPS(klp_patch);
 
+static ssize_t patched_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	struct klp_object *obj;
+
+	obj = container_of(kobj, struct klp_object, kobj);
+	return sysfs_emit(buf, "%d\n", obj->patched);
+}
+
+static struct kobj_attribute patched_kobj_attr = __ATTR_RO(patched);
+static struct attribute *klp_object_attrs[] = {
+	&patched_kobj_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(klp_object);
+
 static void klp_free_object_dynamic(struct klp_object *obj)
 {
 	kfree(obj->name);
@@ -576,6 +593,7 @@ static void klp_kobj_release_object(struct kobject *kobj)
 static struct kobj_type klp_ktype_object = {
 	.release = klp_kobj_release_object,
 	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = klp_object_groups,
 };
 
 static void klp_kobj_release_func(struct kobject *kobj)

tools/testing/selftests/livepatch/Makefile

@@ -6,7 +6,8 @@ TEST_PROGS := \
 	test-callbacks.sh \
 	test-shadow-vars.sh \
 	test-state.sh \
-	test-ftrace.sh
+	test-ftrace.sh \
+	test-sysfs.sh
 
 TEST_FILES := settings
 

tools/testing/selftests/livepatch/functions.sh

@@ -6,6 +6,7 @@
 
 MAX_RETRIES=600
 RETRY_INTERVAL=".1"	# seconds
+KLP_SYSFS_DIR="/sys/kernel/livepatch"
 
 # Kselftest framework requirement - SKIP code is 4
 ksft_skip=4
@@ -308,3 +309,36 @@ function check_result {
 
 	cleanup_dmesg_file
 }
+
+# check_sysfs_rights(modname, rel_path, expected_rights) - check sysfs
+# path permissions
+#	modname - livepatch module creating the sysfs interface
+#	rel_path - relative path of the sysfs interface
+#	expected_rights - expected access rights
+function check_sysfs_rights() {
+	local mod="$1"; shift
+	local rel_path="$1"; shift
+	local expected_rights="$1"; shift
+
+	local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+	local rights=$(/bin/stat --format '%A' "$path")
+	if test "$rights" != "$expected_rights" ; then
+		die "Unexpected access rights of $path: $expected_rights vs. $rights"
+	fi
+}
+
+# check_sysfs_value(modname, rel_path, expected_value) - check sysfs value
+#	modname - livepatch module creating the sysfs interface
+#	rel_path - relative path of the sysfs interface
+#	expected_value - expected value read from the file
+function check_sysfs_value() {
+	local mod="$1"; shift
+	local rel_path="$1"; shift
+	local expected_value="$1"; shift
+
+	local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+	local value=`cat $path`
+	if test "$value" != "$expected_value" ; then
+		die "Unexpected value in $path: $expected_value vs. $value"
+	fi
+}

tools/testing/selftests/livepatch/test-sysfs.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2022 Song Liu <[email protected]>
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_livepatch
+
+setup_config
+
+# - load a livepatch and verifies the sysfs entries work as expected
+
+start_test "sysfs test"
+
+load_lp $MOD_LIVEPATCH
+
+check_sysfs_rights "$MOD_LIVEPATCH" "" "drwxr-xr-x"
+check_sysfs_rights "$MOD_LIVEPATCH" "enabled" "-rw-r--r--"
+check_sysfs_value  "$MOD_LIVEPATCH" "enabled" "1"
+check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------"
+check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
+check_sysfs_value  "$MOD_LIVEPATCH" "transition" "0"
+check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
+check_sysfs_value  "$MOD_LIVEPATCH" "vmlinux/patched" "1"
+
+disable_lp $MOD_LIVEPATCH
+
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
+start_test "sysfs test object/patched"
+
+MOD_LIVEPATCH=test_klp_callbacks_demo
+MOD_TARGET=test_klp_callbacks_mod
+load_lp $MOD_LIVEPATCH
+
+# check the "patch" file changes as target module loads/unloads
+check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+load_mod $MOD_TARGET
+check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "1"
+unload_mod $MOD_TARGET
+check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% modprobe test_klp_callbacks_demo
+livepatch: enabling patch 'test_klp_callbacks_demo'
+livepatch: 'test_klp_callbacks_demo': initializing patching transition
+test_klp_callbacks_demo: pre_patch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': starting patching transition
+livepatch: 'test_klp_callbacks_demo': completing patching transition
+test_klp_callbacks_demo: post_patch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': patching complete
+% modprobe test_klp_callbacks_mod
+livepatch: applying patch 'test_klp_callbacks_demo' to loading module 'test_klp_callbacks_mod'
+test_klp_callbacks_demo: pre_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
+test_klp_callbacks_demo: post_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init
+test_klp_callbacks_mod: test_klp_callbacks_mod_init
+% rmmod test_klp_callbacks_mod
+test_klp_callbacks_mod: test_klp_callbacks_mod_exit
+test_klp_callbacks_demo: pre_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
+livepatch: reverting patch 'test_klp_callbacks_demo' on unloading module 'test_klp_callbacks_mod'
+test_klp_callbacks_demo: post_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
+% echo 0 > /sys/kernel/livepatch/test_klp_callbacks_demo/enabled
+livepatch: 'test_klp_callbacks_demo': initializing unpatching transition
+test_klp_callbacks_demo: pre_unpatch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': starting unpatching transition
+livepatch: 'test_klp_callbacks_demo': completing unpatching transition
+test_klp_callbacks_demo: post_unpatch_callback: vmlinux
+livepatch: 'test_klp_callbacks_demo': unpatching complete
+% rmmod test_klp_callbacks_demo"
+
+exit 0