linux-stable/drivers/misc/lkdtm_core.c
Kees Cook e22aa9d781 lkdtm: add bad USER_DS test
This adds CORRUPT_USER_DS to check that the get_fs() test on syscall
return (via __VERIFY_PRE_USERMODE_STATE) still sees USER_DS. Since
trying to deal with values other than USER_DS and KERNEL_DS across all
architectures in a safe way is not sensible, this sets KERNEL_DS, but
since that could be extremely dangerous if the protection is not present,
it also raises SIGKILL for current, so that no matter what, the process
will die. A successful test will be visible with a BUG(), like all the
other LKDTM tests.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-08 17:56:02 +02:00

553 lines
14 KiB
C

/*
* Linux Kernel Dump Test Module for testing kernel crashes conditions:
* induces system failures at predefined crashpoints and under predefined
* operational conditions in order to evaluate the reliability of kernel
* sanity checking and crash dumps obtained using different dumping
* solutions.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
*
* Author: Ankita Garg <ankita@in.ibm.com>
*
* It is adapted from the Linux Kernel Dump Test Tool by
* Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
*
* Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
*
* See Documentation/fault-injection/provoke-crashes.txt for instructions
*/
#include "lkdtm.h"
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/kprobes.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/hrtimer.h>
#include <linux/slab.h>
#include <scsi/scsi_cmnd.h>
#include <linux/debugfs.h>
#ifdef CONFIG_IDE
#include <linux/ide.h>
#endif
#define DEFAULT_COUNT 10
static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
size_t count, loff_t *off);
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
size_t count, loff_t *off);
#ifdef CONFIG_KPROBES
static void lkdtm_handler(void);
static ssize_t lkdtm_debugfs_entry(struct file *f,
const char __user *user_buf,
size_t count, loff_t *off);
/* jprobe entry point handlers. */
static unsigned int jp_do_irq(unsigned int irq)
{
lkdtm_handler();
jprobe_return();
return 0;
}
static irqreturn_t jp_handle_irq_event(unsigned int irq,
struct irqaction *action)
{
lkdtm_handler();
jprobe_return();
return 0;
}
static void jp_tasklet_action(struct softirq_action *a)
{
lkdtm_handler();
jprobe_return();
}
static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
{
lkdtm_handler();
jprobe_return();
}
struct scan_control;
static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
struct zone *zone,
struct scan_control *sc)
{
lkdtm_handler();
jprobe_return();
return 0;
}
static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
const enum hrtimer_mode mode)
{
lkdtm_handler();
jprobe_return();
return 0;
}
static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
{
lkdtm_handler();
jprobe_return();
return 0;
}
# ifdef CONFIG_IDE
static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
struct block_device *bdev, unsigned int cmd,
unsigned long arg)
{
lkdtm_handler();
jprobe_return();
return 0;
}
# endif
#endif
/* Crash points */
struct crashpoint {
const char *name;
const struct file_operations fops;
struct jprobe jprobe;
};
#define CRASHPOINT(_name, _write, _symbol, _entry) \
{ \
.name = _name, \
.fops = { \
.read = lkdtm_debugfs_read, \
.llseek = generic_file_llseek, \
.open = lkdtm_debugfs_open, \
.write = _write, \
}, \
.jprobe = { \
.kp.symbol_name = _symbol, \
.entry = (kprobe_opcode_t *)_entry, \
}, \
}
/* Define the possible places where we can trigger a crash point. */
struct crashpoint crashpoints[] = {
CRASHPOINT("DIRECT", direct_entry,
NULL, NULL),
#ifdef CONFIG_KPROBES
CRASHPOINT("INT_HARDWARE_ENTRY", lkdtm_debugfs_entry,
"do_IRQ", jp_do_irq),
CRASHPOINT("INT_HW_IRQ_EN", lkdtm_debugfs_entry,
"handle_IRQ_event", jp_handle_irq_event),
CRASHPOINT("INT_TASKLET_ENTRY", lkdtm_debugfs_entry,
"tasklet_action", jp_tasklet_action),
CRASHPOINT("FS_DEVRW", lkdtm_debugfs_entry,
"ll_rw_block", jp_ll_rw_block),
CRASHPOINT("MEM_SWAPOUT", lkdtm_debugfs_entry,
"shrink_inactive_list", jp_shrink_inactive_list),
CRASHPOINT("TIMERADD", lkdtm_debugfs_entry,
"hrtimer_start", jp_hrtimer_start),
CRASHPOINT("SCSI_DISPATCH_CMD", lkdtm_debugfs_entry,
"scsi_dispatch_cmd", jp_scsi_dispatch_cmd),
# ifdef CONFIG_IDE
CRASHPOINT("IDE_CORE_CP", lkdtm_debugfs_entry,
"generic_ide_ioctl", jp_generic_ide_ioctl),
# endif
#endif
};
/* Crash types. */
struct crashtype {
const char *name;
void (*func)(void);
};
#define CRASHTYPE(_name) \
{ \
.name = __stringify(_name), \
.func = lkdtm_ ## _name, \
}
/* Define the possible types of crashes that can be triggered. */
struct crashtype crashtypes[] = {
CRASHTYPE(PANIC),
CRASHTYPE(BUG),
CRASHTYPE(WARNING),
CRASHTYPE(EXCEPTION),
CRASHTYPE(LOOP),
CRASHTYPE(OVERFLOW),
CRASHTYPE(CORRUPT_LIST_ADD),
CRASHTYPE(CORRUPT_LIST_DEL),
CRASHTYPE(CORRUPT_USER_DS),
CRASHTYPE(CORRUPT_STACK),
CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
CRASHTYPE(OVERWRITE_ALLOCATION),
CRASHTYPE(WRITE_AFTER_FREE),
CRASHTYPE(READ_AFTER_FREE),
CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
CRASHTYPE(READ_BUDDY_AFTER_FREE),
CRASHTYPE(SOFTLOCKUP),
CRASHTYPE(HARDLOCKUP),
CRASHTYPE(SPINLOCKUP),
CRASHTYPE(HUNG_TASK),
CRASHTYPE(EXEC_DATA),
CRASHTYPE(EXEC_STACK),
CRASHTYPE(EXEC_KMALLOC),
CRASHTYPE(EXEC_VMALLOC),
CRASHTYPE(EXEC_RODATA),
CRASHTYPE(EXEC_USERSPACE),
CRASHTYPE(ACCESS_USERSPACE),
CRASHTYPE(WRITE_RO),
CRASHTYPE(WRITE_RO_AFTER_INIT),
CRASHTYPE(WRITE_KERN),
CRASHTYPE(REFCOUNT_SATURATE_INC),
CRASHTYPE(REFCOUNT_SATURATE_ADD),
CRASHTYPE(REFCOUNT_ZERO_DEC),
CRASHTYPE(REFCOUNT_ZERO_INC),
CRASHTYPE(REFCOUNT_ZERO_SUB),
CRASHTYPE(REFCOUNT_ZERO_ADD),
CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
CRASHTYPE(USERCOPY_HEAP_FLAG_TO),
CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
CRASHTYPE(USERCOPY_STACK_FRAME_TO),
CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
CRASHTYPE(USERCOPY_STACK_BEYOND),
CRASHTYPE(USERCOPY_KERNEL),
};
/* Global jprobe entry and crashtype. */
static struct jprobe *lkdtm_jprobe;
struct crashpoint *lkdtm_crashpoint;
struct crashtype *lkdtm_crashtype;
/* Module parameters */
static int recur_count = -1;
module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
static char* cpoint_name;
module_param(cpoint_name, charp, 0444);
MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
static char* cpoint_type;
module_param(cpoint_type, charp, 0444);
MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
"hitting the crash point");
static int cpoint_count = DEFAULT_COUNT;
module_param(cpoint_count, int, 0644);
MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
"crash point is to be hit to trigger action");
/* Return the crashtype number or NULL if the name is invalid */
static struct crashtype *find_crashtype(const char *name)
{
int i;
for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
if (!strcmp(name, crashtypes[i].name))
return &crashtypes[i];
}
return NULL;
}
/*
* This is forced noinline just so it distinctly shows up in the stackdump
* which makes validation of expected lkdtm crashes easier.
*/
static noinline void lkdtm_do_action(struct crashtype *crashtype)
{
BUG_ON(!crashtype || !crashtype->func);
crashtype->func();
}
static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
struct crashtype *crashtype)
{
int ret;
/* If this doesn't have a symbol, just call immediately. */
if (!crashpoint->jprobe.kp.symbol_name) {
lkdtm_do_action(crashtype);
return 0;
}
if (lkdtm_jprobe != NULL)
unregister_jprobe(lkdtm_jprobe);
lkdtm_crashpoint = crashpoint;
lkdtm_crashtype = crashtype;
lkdtm_jprobe = &crashpoint->jprobe;
ret = register_jprobe(lkdtm_jprobe);
if (ret < 0) {
pr_info("Couldn't register jprobe %s\n",
crashpoint->jprobe.kp.symbol_name);
lkdtm_jprobe = NULL;
lkdtm_crashpoint = NULL;
lkdtm_crashtype = NULL;
}
return ret;
}
#ifdef CONFIG_KPROBES
/* Global crash counter and spinlock. */
static int crash_count = DEFAULT_COUNT;
static DEFINE_SPINLOCK(crash_count_lock);
/* Called by jprobe entry points. */
static void lkdtm_handler(void)
{
unsigned long flags;
bool do_it = false;
BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
spin_lock_irqsave(&crash_count_lock, flags);
crash_count--;
pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
if (crash_count == 0) {
do_it = true;
crash_count = cpoint_count;
}
spin_unlock_irqrestore(&crash_count_lock, flags);
if (do_it)
lkdtm_do_action(lkdtm_crashtype);
}
static ssize_t lkdtm_debugfs_entry(struct file *f,
const char __user *user_buf,
size_t count, loff_t *off)
{
struct crashpoint *crashpoint = file_inode(f)->i_private;
struct crashtype *crashtype = NULL;
char *buf;
int err;
if (count >= PAGE_SIZE)
return -EINVAL;
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, user_buf, count)) {
free_page((unsigned long) buf);
return -EFAULT;
}
/* NULL-terminate and remove enter */
buf[count] = '\0';
strim(buf);
crashtype = find_crashtype(buf);
free_page((unsigned long)buf);
if (!crashtype)
return -EINVAL;
err = lkdtm_register_cpoint(crashpoint, crashtype);
if (err < 0)
return err;
*off += count;
return count;
}
#endif
/* Generic read callback that just prints out the available crash types */
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
size_t count, loff_t *off)
{
char *buf;
int i, n, out;
buf = (char *)__get_free_page(GFP_KERNEL);
if (buf == NULL)
return -ENOMEM;
n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
crashtypes[i].name);
}
buf[n] = '\0';
out = simple_read_from_buffer(user_buf, count, off,
buf, n);
free_page((unsigned long) buf);
return out;
}
static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
{
return 0;
}
/* Special entry to just crash directly. Available without KPROBEs */
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
size_t count, loff_t *off)
{
struct crashtype *crashtype;
char *buf;
if (count >= PAGE_SIZE)
return -EINVAL;
if (count < 1)
return -EINVAL;
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, user_buf, count)) {
free_page((unsigned long) buf);
return -EFAULT;
}
/* NULL-terminate and remove enter */
buf[count] = '\0';
strim(buf);
crashtype = find_crashtype(buf);
free_page((unsigned long) buf);
if (!crashtype)
return -EINVAL;
pr_info("Performing direct entry %s\n", crashtype->name);
lkdtm_do_action(crashtype);
*off += count;
return count;
}
static struct dentry *lkdtm_debugfs_root;
static int __init lkdtm_module_init(void)
{
struct crashpoint *crashpoint = NULL;
struct crashtype *crashtype = NULL;
int ret = -EINVAL;
int i;
/* Neither or both of these need to be set */
if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
pr_err("Need both cpoint_type and cpoint_name or neither\n");
return -EINVAL;
}
if (cpoint_type) {
crashtype = find_crashtype(cpoint_type);
if (!crashtype) {
pr_err("Unknown crashtype '%s'\n", cpoint_type);
return -EINVAL;
}
}
if (cpoint_name) {
for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
if (!strcmp(cpoint_name, crashpoints[i].name))
crashpoint = &crashpoints[i];
}
/* Refuse unknown crashpoints. */
if (!crashpoint) {
pr_err("Invalid crashpoint %s\n", cpoint_name);
return -EINVAL;
}
}
#ifdef CONFIG_KPROBES
/* Set crash count. */
crash_count = cpoint_count;
#endif
/* Handle test-specific initialization. */
lkdtm_bugs_init(&recur_count);
lkdtm_perms_init();
lkdtm_usercopy_init();
/* Register debugfs interface */
lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
if (!lkdtm_debugfs_root) {
pr_err("creating root dir failed\n");
return -ENODEV;
}
/* Install debugfs trigger files. */
for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
struct crashpoint *cur = &crashpoints[i];
struct dentry *de;
de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
cur, &cur->fops);
if (de == NULL) {
pr_err("could not create crashpoint %s\n", cur->name);
goto out_err;
}
}
/* Install crashpoint if one was selected. */
if (crashpoint) {
ret = lkdtm_register_cpoint(crashpoint, crashtype);
if (ret < 0) {
pr_info("Invalid crashpoint %s\n", crashpoint->name);
goto out_err;
}
pr_info("Crash point %s of type %s registered\n",
crashpoint->name, cpoint_type);
} else {
pr_info("No crash points registered, enable through debugfs\n");
}
return 0;
out_err:
debugfs_remove_recursive(lkdtm_debugfs_root);
return ret;
}
static void __exit lkdtm_module_exit(void)
{
debugfs_remove_recursive(lkdtm_debugfs_root);
/* Handle test-specific clean-up. */
lkdtm_usercopy_exit();
if (lkdtm_jprobe != NULL)
unregister_jprobe(lkdtm_jprobe);
pr_info("Crash point unregistered\n");
}
module_init(lkdtm_module_init);
module_exit(lkdtm_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kernel crash testing module");