Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching fixes from Jiri Kosina:
- symbol lookup locking fix, from Miroslav Benes
- error handling improvements in case of failure of the module coming
notifier, from Minfei Huang
- we were too pessimistic when kASLR has been enabled on x86 and were
dropping address hints on the floor unnecessarily in such case. Fix
from Jiri Kosina
- a few other small fixes and cleanups
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: add module locking around kallsyms calls
livepatch: annotate klp_init() with __init
livepatch: introduce patch/func-walking helpers
livepatch: make kobject in klp_object statically allocated
livepatch: Prevent patch inconsistencies if the coming module notifier fails
livepatch: match return value to function signature
x86: kaslr: fix build due to missing ALIGN definition
livepatch: x86: make kASLR logic more accurate
x86: introduce kaslr_offset()
diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h
index 2d29197..19c099a 100644
--- a/arch/x86/include/asm/livepatch.h
+++ b/arch/x86/include/asm/livepatch.h
@@ -21,6 +21,7 @@
#ifndef _ASM_X86_LIVEPATCH_H
#define _ASM_X86_LIVEPATCH_H
+#include <asm/setup.h>
#include <linux/module.h>
#include <linux/ftrace.h>
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index f69e06b..11af24e 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -60,17 +60,24 @@
#ifndef _SETUP
#include <asm/espfix.h>
+#include <linux/kernel.h>
/*
* This is set up by the setup-routine at boot-time
*/
extern struct boot_params boot_params;
+extern char _text[];
static inline bool kaslr_enabled(void)
{
return !!(boot_params.hdr.loadflags & KASLR_FLAG);
}
+static inline unsigned long kaslr_offset(void)
+{
+ return (unsigned long)&_text - __START_KERNEL;
+}
+
/*
* Do NOT EVER look at the BIOS memory size location.
* It does not work on many machines.
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 11546b4..819ab3f 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -26,6 +26,7 @@
#include <asm/io_apic.h>
#include <asm/debugreg.h>
#include <asm/kexec-bzimage64.h>
+#include <asm/setup.h>
#ifdef CONFIG_KEXEC_FILE
static struct kexec_file_ops *kexec_file_loaders[] = {
@@ -335,7 +336,7 @@
VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
- (unsigned long)&_text - __START_KERNEL);
+ kaslr_offset());
}
/* arch-dependent functionality related to kexec file-based syscall */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 265a6fd..39ca113 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -836,7 +836,7 @@
{
if (kaslr_enabled()) {
pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
- (unsigned long)&_text - __START_KERNEL,
+ kaslr_offset(),
__START_KERNEL,
__START_KERNEL_map,
MODULES_VADDR-1);
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index ee6dbb3..31db7a0 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -99,7 +99,7 @@
struct klp_func *funcs;
/* internal */
- struct kobject *kobj;
+ struct kobject kobj;
struct module *mod;
enum klp_state state;
};
@@ -123,6 +123,12 @@
enum klp_state state;
};
+#define klp_for_each_object(patch, obj) \
+ for (obj = patch->objs; obj->funcs; obj++)
+
+#define klp_for_each_func(obj, func) \
+ for (func = obj->funcs; func->old_name; func++)
+
int klp_register_patch(struct klp_patch *);
int klp_unregister_patch(struct klp_patch *);
int klp_enable_patch(struct klp_patch *);
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 284e269..c40ebcc 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -128,7 +128,7 @@
static bool klp_initialized(void)
{
- return klp_root_kobj;
+ return !!klp_root_kobj;
}
struct klp_find_arg {
@@ -179,7 +179,9 @@
.count = 0
};
+ mutex_lock(&module_mutex);
kallsyms_on_each_symbol(klp_find_callback, &args);
+ mutex_unlock(&module_mutex);
if (args.count == 0)
pr_err("symbol '%s' not found in symbol table\n", name);
@@ -219,13 +221,19 @@
.name = name,
.addr = addr,
};
+ int ret;
- if (kallsyms_on_each_symbol(klp_verify_callback, &args))
- return 0;
+ mutex_lock(&module_mutex);
+ ret = kallsyms_on_each_symbol(klp_verify_callback, &args);
+ mutex_unlock(&module_mutex);
- pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
- name, addr);
- return -EINVAL;
+ if (!ret) {
+ pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
+ name, addr);
+ return -EINVAL;
+ }
+
+ return 0;
}
static int klp_find_verify_func_addr(struct klp_object *obj,
@@ -234,8 +242,9 @@
int ret;
#if defined(CONFIG_RANDOMIZE_BASE)
- /* KASLR is enabled, disregard old_addr from user */
- func->old_addr = 0;
+ /* If KASLR has been enabled, adjust old_addr accordingly */
+ if (kaslr_enabled() && func->old_addr)
+ func->old_addr += kaslr_offset();
#endif
if (!func->old_addr || klp_is_module(obj))
@@ -422,7 +431,7 @@
{
struct klp_func *func;
- for (func = obj->funcs; func->old_name; func++)
+ klp_for_each_func(obj, func)
if (func->state == KLP_ENABLED)
klp_disable_func(func);
@@ -440,7 +449,7 @@
if (WARN_ON(!klp_is_object_loaded(obj)))
return -EINVAL;
- for (func = obj->funcs; func->old_name; func++) {
+ klp_for_each_func(obj, func) {
ret = klp_enable_func(func);
if (ret) {
klp_disable_object(obj);
@@ -463,7 +472,7 @@
pr_notice("disabling patch '%s'\n", patch->mod->name);
- for (obj = patch->objs; obj->funcs; obj++) {
+ klp_for_each_object(patch, obj) {
if (obj->state == KLP_ENABLED)
klp_disable_object(obj);
}
@@ -523,7 +532,7 @@
pr_notice("enabling patch '%s'\n", patch->mod->name);
- for (obj = patch->objs; obj->funcs; obj++) {
+ klp_for_each_object(patch, obj) {
if (!klp_is_object_loaded(obj))
continue;
@@ -651,6 +660,15 @@
.default_attrs = klp_patch_attrs,
};
+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,
+};
+
static void klp_kobj_release_func(struct kobject *kobj)
{
}
@@ -680,7 +698,7 @@
obj->mod = NULL;
- for (func = obj->funcs; func->old_name; func++)
+ klp_for_each_func(obj, func)
func->old_addr = 0;
}
@@ -695,7 +713,7 @@
for (obj = patch->objs; obj->funcs && obj != limit; obj++) {
klp_free_funcs_limited(obj, NULL);
- kobject_put(obj->kobj);
+ kobject_put(&obj->kobj);
}
}
@@ -713,7 +731,7 @@
func->state = KLP_DISABLED;
return kobject_init_and_add(&func->kobj, &klp_ktype_func,
- obj->kobj, "%s", func->old_name);
+ &obj->kobj, "%s", func->old_name);
}
/* parts of the initialization that is done only when the object is loaded */
@@ -729,7 +747,7 @@
return ret;
}
- for (func = obj->funcs; func->old_name; func++) {
+ klp_for_each_func(obj, func) {
ret = klp_find_verify_func_addr(obj, func);
if (ret)
return ret;
@@ -753,11 +771,12 @@
klp_find_object_module(obj);
name = klp_is_module(obj) ? obj->name : "vmlinux";
- obj->kobj = kobject_create_and_add(name, &patch->kobj);
- if (!obj->kobj)
- return -ENOMEM;
+ ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object,
+ &patch->kobj, "%s", name);
+ if (ret)
+ return ret;
- for (func = obj->funcs; func->old_name; func++) {
+ klp_for_each_func(obj, func) {
ret = klp_init_func(obj, func);
if (ret)
goto free;
@@ -773,7 +792,7 @@
free:
klp_free_funcs_limited(obj, func);
- kobject_put(obj->kobj);
+ kobject_put(&obj->kobj);
return ret;
}
@@ -794,7 +813,7 @@
if (ret)
goto unlock;
- for (obj = patch->objs; obj->funcs; obj++) {
+ klp_for_each_object(patch, obj) {
ret = klp_init_object(patch, obj);
if (ret)
goto free;
@@ -883,7 +902,7 @@
}
EXPORT_SYMBOL_GPL(klp_register_patch);
-static void klp_module_notify_coming(struct klp_patch *patch,
+static int klp_module_notify_coming(struct klp_patch *patch,
struct klp_object *obj)
{
struct module *pmod = patch->mod;
@@ -891,22 +910,23 @@
int ret;
ret = klp_init_object_loaded(patch, obj);
- if (ret)
- goto err;
+ if (ret) {
+ pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",
+ pmod->name, mod->name, ret);
+ return ret;
+ }
if (patch->state == KLP_DISABLED)
- return;
+ return 0;
pr_notice("applying patch '%s' to loading module '%s'\n",
pmod->name, mod->name);
ret = klp_enable_object(obj);
- if (!ret)
- return;
-
-err:
- pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
- pmod->name, mod->name, ret);
+ if (ret)
+ pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
+ pmod->name, mod->name, ret);
+ return ret;
}
static void klp_module_notify_going(struct klp_patch *patch,
@@ -930,6 +950,7 @@
static int klp_module_notify(struct notifier_block *nb, unsigned long action,
void *data)
{
+ int ret;
struct module *mod = data;
struct klp_patch *patch;
struct klp_object *obj;
@@ -949,13 +970,18 @@
mod->klp_alive = false;
list_for_each_entry(patch, &klp_patches, list) {
- for (obj = patch->objs; obj->funcs; obj++) {
+ klp_for_each_object(patch, obj) {
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
continue;
if (action == MODULE_STATE_COMING) {
obj->mod = mod;
- klp_module_notify_coming(patch, obj);
+ ret = klp_module_notify_coming(patch, obj);
+ if (ret) {
+ obj->mod = NULL;
+ pr_warn("patch '%s' is in an inconsistent state!\n",
+ patch->mod->name);
+ }
} else /* MODULE_STATE_GOING */
klp_module_notify_going(patch, obj);
@@ -973,7 +999,7 @@
.priority = INT_MIN+1, /* called late but before ftrace notifier */
};
-static int klp_init(void)
+static int __init klp_init(void)
{
int ret;