From 9e197e2f894c0270ffabd314d73c7730b09ac63c Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 22 Feb 2016 14:05:44 -0800 Subject: lkdtm: split build into multiple source files Kbuild lacks a way to do in-place objcopy or other modifications of built targets, so in order to move functions into non-text sections without renaming the kernel module, the build of lkdtm must be split into separate source files. This renames lkdtm.c to lkdtm_core.c in preparation for adding the source file for the .rodata section. Signed-off-by: Kees Cook --- drivers/misc/Makefile | 2 + drivers/misc/lkdtm.c | 1023 --------------------------------------------- drivers/misc/lkdtm_core.c | 1023 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 1025 insertions(+), 1023 deletions(-) delete mode 100644 drivers/misc/lkdtm.c create mode 100644 drivers/misc/lkdtm_core.c diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index b2fb6dbffcef..c3cb6ad8cc37 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -57,3 +57,5 @@ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o obj-$(CONFIG_CXL_BASE) += cxl/ obj-$(CONFIG_PANEL) += panel.o + +lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c deleted file mode 100644 index 0a5cbbe12452..000000000000 --- a/drivers/misc/lkdtm.c +++ /dev/null @@ -1,1023 +0,0 @@ -/* - * Kprobe module for testing crash dumps - * - * 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 - * - * This module induces system failures at predefined crashpoints to - * evaluate the reliability of crash dumps obtained using different dumping - * solutions. - * - * It is adapted from the Linux Kernel Dump Test Tool by - * Fernando Luis Vazquez Cao - * - * Debugfs support added by Simon Kagstrom - * - * See Documentation/fault-injection/provoke-crashes.txt for instructions - */ -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#ifdef CONFIG_IDE -#include -#endif - -/* - * Make sure our attempts to over run the kernel stack doesn't trigger - * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we - * recurse past the end of THREAD_SIZE by default. - */ -#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0) -#define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2) -#else -#define REC_STACK_SIZE (THREAD_SIZE / 8) -#endif -#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2) - -#define DEFAULT_COUNT 10 -#define EXEC_SIZE 64 - -enum cname { - CN_INVALID, - CN_INT_HARDWARE_ENTRY, - CN_INT_HW_IRQ_EN, - CN_INT_TASKLET_ENTRY, - CN_FS_DEVRW, - CN_MEM_SWAPOUT, - CN_TIMERADD, - CN_SCSI_DISPATCH_CMD, - CN_IDE_CORE_CP, - CN_DIRECT, -}; - -enum ctype { - CT_NONE, - CT_PANIC, - CT_BUG, - CT_WARNING, - CT_EXCEPTION, - CT_LOOP, - CT_OVERFLOW, - CT_CORRUPT_STACK, - CT_UNALIGNED_LOAD_STORE_WRITE, - CT_OVERWRITE_ALLOCATION, - CT_WRITE_AFTER_FREE, - CT_READ_AFTER_FREE, - CT_WRITE_BUDDY_AFTER_FREE, - CT_READ_BUDDY_AFTER_FREE, - CT_SOFTLOCKUP, - CT_HARDLOCKUP, - CT_SPINLOCKUP, - CT_HUNG_TASK, - CT_EXEC_DATA, - CT_EXEC_STACK, - CT_EXEC_KMALLOC, - CT_EXEC_VMALLOC, - CT_EXEC_USERSPACE, - CT_ACCESS_USERSPACE, - CT_WRITE_RO, - CT_WRITE_RO_AFTER_INIT, - CT_WRITE_KERN, - CT_WRAP_ATOMIC -}; - -static char* cp_name[] = { - "INT_HARDWARE_ENTRY", - "INT_HW_IRQ_EN", - "INT_TASKLET_ENTRY", - "FS_DEVRW", - "MEM_SWAPOUT", - "TIMERADD", - "SCSI_DISPATCH_CMD", - "IDE_CORE_CP", - "DIRECT", -}; - -static char* cp_type[] = { - "PANIC", - "BUG", - "WARNING", - "EXCEPTION", - "LOOP", - "OVERFLOW", - "CORRUPT_STACK", - "UNALIGNED_LOAD_STORE_WRITE", - "OVERWRITE_ALLOCATION", - "WRITE_AFTER_FREE", - "READ_AFTER_FREE", - "WRITE_BUDDY_AFTER_FREE", - "READ_BUDDY_AFTER_FREE", - "SOFTLOCKUP", - "HARDLOCKUP", - "SPINLOCKUP", - "HUNG_TASK", - "EXEC_DATA", - "EXEC_STACK", - "EXEC_KMALLOC", - "EXEC_VMALLOC", - "EXEC_USERSPACE", - "ACCESS_USERSPACE", - "WRITE_RO", - "WRITE_RO_AFTER_INIT", - "WRITE_KERN", - "WRAP_ATOMIC" -}; - -static struct jprobe lkdtm; - -static int lkdtm_parse_commandline(void); -static void lkdtm_handler(void); - -static char* cpoint_name; -static char* cpoint_type; -static int cpoint_count = DEFAULT_COUNT; -static int recur_count = REC_NUM_DEFAULT; - -static enum cname cpoint = CN_INVALID; -static enum ctype cptype = CT_NONE; -static int count = DEFAULT_COUNT; -static DEFINE_SPINLOCK(count_lock); -static DEFINE_SPINLOCK(lock_me_up); - -static u8 data_area[EXEC_SIZE]; - -static const unsigned long rodata = 0xAA55AA55; -static unsigned long ro_after_init __ro_after_init = 0x55AA5500; - -module_param(recur_count, int, 0644); -MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); -module_param(cpoint_name, charp, 0444); -MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); -module_param(cpoint_type, charp, 0444); -MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ - "hitting the crash point"); -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"); - -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 - -/* Return the crashpoint number or NONE if the name is invalid */ -static enum ctype parse_cp_type(const char *what, size_t count) -{ - int i; - - for (i = 0; i < ARRAY_SIZE(cp_type); i++) { - if (!strcmp(what, cp_type[i])) - return i + 1; - } - - return CT_NONE; -} - -static const char *cp_type_to_str(enum ctype type) -{ - if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type)) - return "None"; - - return cp_type[type - 1]; -} - -static const char *cp_name_to_str(enum cname name) -{ - if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name)) - return "INVALID"; - - return cp_name[name - 1]; -} - - -static int lkdtm_parse_commandline(void) -{ - int i; - unsigned long flags; - - if (cpoint_count < 1 || recur_count < 1) - return -EINVAL; - - spin_lock_irqsave(&count_lock, flags); - count = cpoint_count; - spin_unlock_irqrestore(&count_lock, flags); - - /* No special parameters */ - if (!cpoint_type && !cpoint_name) - return 0; - - /* Neither or both of these need to be set */ - if (!cpoint_type || !cpoint_name) - return -EINVAL; - - cptype = parse_cp_type(cpoint_type, strlen(cpoint_type)); - if (cptype == CT_NONE) - return -EINVAL; - - for (i = 0; i < ARRAY_SIZE(cp_name); i++) { - if (!strcmp(cpoint_name, cp_name[i])) { - cpoint = i + 1; - return 0; - } - } - - /* Could not find a valid crash point */ - return -EINVAL; -} - -static int recursive_loop(int remaining) -{ - char buf[REC_STACK_SIZE]; - - /* Make sure compiler does not optimize this away. */ - memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE); - if (!remaining) - return 0; - else - return recursive_loop(remaining - 1); -} - -static void do_nothing(void) -{ - return; -} - -/* Must immediately follow do_nothing for size calculuations to work out. */ -static void do_overwritten(void) -{ - pr_info("do_overwritten wasn't overwritten!\n"); - return; -} - -static noinline void corrupt_stack(void) -{ - /* Use default char array length that triggers stack protection. */ - char data[8]; - - memset((void *)data, 0, 64); -} - -static void noinline execute_location(void *dst) -{ - void (*func)(void) = dst; - - pr_info("attempting ok execution at %p\n", do_nothing); - do_nothing(); - - memcpy(dst, do_nothing, EXEC_SIZE); - flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); - pr_info("attempting bad execution at %p\n", func); - func(); -} - -static void execute_user_location(void *dst) -{ - /* Intentionally crossing kernel/user memory boundary. */ - void (*func)(void) = dst; - - pr_info("attempting ok execution at %p\n", do_nothing); - do_nothing(); - - if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE)) - return; - flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); - pr_info("attempting bad execution at %p\n", func); - func(); -} - -static void lkdtm_do_action(enum ctype which) -{ - switch (which) { - case CT_PANIC: - panic("dumptest"); - break; - case CT_BUG: - BUG(); - break; - case CT_WARNING: - WARN_ON(1); - break; - case CT_EXCEPTION: - *((int *) 0) = 0; - break; - case CT_LOOP: - for (;;) - ; - break; - case CT_OVERFLOW: - (void) recursive_loop(recur_count); - break; - case CT_CORRUPT_STACK: - corrupt_stack(); - break; - case CT_UNALIGNED_LOAD_STORE_WRITE: { - static u8 data[5] __attribute__((aligned(4))) = {1, 2, - 3, 4, 5}; - u32 *p; - u32 val = 0x12345678; - - p = (u32 *)(data + 1); - if (*p == 0) - val = 0x87654321; - *p = val; - break; - } - case CT_OVERWRITE_ALLOCATION: { - size_t len = 1020; - u32 *data = kmalloc(len, GFP_KERNEL); - - data[1024 / sizeof(u32)] = 0x12345678; - kfree(data); - break; - } - case CT_WRITE_AFTER_FREE: { - int *base, *again; - size_t len = 1024; - /* - * The slub allocator uses the first word to store the free - * pointer in some configurations. Use the middle of the - * allocation to avoid running into the freelist - */ - size_t offset = (len / sizeof(*base)) / 2; - - base = kmalloc(len, GFP_KERNEL); - pr_info("Allocated memory %p-%p\n", base, &base[offset * 2]); - pr_info("Attempting bad write to freed memory at %p\n", - &base[offset]); - kfree(base); - base[offset] = 0x0abcdef0; - /* Attempt to notice the overwrite. */ - again = kmalloc(len, GFP_KERNEL); - kfree(again); - if (again != base) - pr_info("Hmm, didn't get the same memory range.\n"); - - break; - } - case CT_READ_AFTER_FREE: { - int *base, *val, saw; - size_t len = 1024; - /* - * The slub allocator uses the first word to store the free - * pointer in some configurations. Use the middle of the - * allocation to avoid running into the freelist - */ - size_t offset = (len / sizeof(*base)) / 2; - - base = kmalloc(len, GFP_KERNEL); - if (!base) - break; - - val = kmalloc(len, GFP_KERNEL); - if (!val) { - kfree(base); - break; - } - - *val = 0x12345678; - base[offset] = *val; - pr_info("Value in memory before free: %x\n", base[offset]); - - kfree(base); - - pr_info("Attempting bad read from freed memory\n"); - saw = base[offset]; - if (saw != *val) { - /* Good! Poisoning happened, so declare a win. */ - pr_info("Memory correctly poisoned (%x)\n", saw); - BUG(); - } - pr_info("Memory was not poisoned\n"); - - kfree(val); - break; - } - case CT_WRITE_BUDDY_AFTER_FREE: { - unsigned long p = __get_free_page(GFP_KERNEL); - if (!p) - break; - pr_info("Writing to the buddy page before free\n"); - memset((void *)p, 0x3, PAGE_SIZE); - free_page(p); - schedule(); - pr_info("Attempting bad write to the buddy page after free\n"); - memset((void *)p, 0x78, PAGE_SIZE); - /* Attempt to notice the overwrite. */ - p = __get_free_page(GFP_KERNEL); - free_page(p); - schedule(); - - break; - } - case CT_READ_BUDDY_AFTER_FREE: { - unsigned long p = __get_free_page(GFP_KERNEL); - int saw, *val; - int *base; - - if (!p) - break; - - val = kmalloc(1024, GFP_KERNEL); - if (!val) { - free_page(p); - break; - } - - base = (int *)p; - - *val = 0x12345678; - base[0] = *val; - pr_info("Value in memory before free: %x\n", base[0]); - free_page(p); - pr_info("Attempting to read from freed memory\n"); - saw = base[0]; - if (saw != *val) { - /* Good! Poisoning happened, so declare a win. */ - pr_info("Memory correctly poisoned (%x)\n", saw); - BUG(); - } - pr_info("Buddy page was not poisoned\n"); - - kfree(val); - break; - } - case CT_SOFTLOCKUP: - preempt_disable(); - for (;;) - cpu_relax(); - break; - case CT_HARDLOCKUP: - local_irq_disable(); - for (;;) - cpu_relax(); - break; - case CT_SPINLOCKUP: - /* Must be called twice to trigger. */ - spin_lock(&lock_me_up); - /* Let sparse know we intended to exit holding the lock. */ - __release(&lock_me_up); - break; - case CT_HUNG_TASK: - set_current_state(TASK_UNINTERRUPTIBLE); - schedule(); - break; - case CT_EXEC_DATA: - execute_location(data_area); - break; - case CT_EXEC_STACK: { - u8 stack_area[EXEC_SIZE]; - execute_location(stack_area); - break; - } - case CT_EXEC_KMALLOC: { - u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL); - execute_location(kmalloc_area); - kfree(kmalloc_area); - break; - } - case CT_EXEC_VMALLOC: { - u32 *vmalloc_area = vmalloc(EXEC_SIZE); - execute_location(vmalloc_area); - vfree(vmalloc_area); - break; - } - case CT_EXEC_USERSPACE: { - unsigned long user_addr; - - user_addr = vm_mmap(NULL, 0, PAGE_SIZE, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_ANONYMOUS | MAP_PRIVATE, 0); - if (user_addr >= TASK_SIZE) { - pr_warn("Failed to allocate user memory\n"); - return; - } - execute_user_location((void *)user_addr); - vm_munmap(user_addr, PAGE_SIZE); - break; - } - case CT_ACCESS_USERSPACE: { - unsigned long user_addr, tmp = 0; - unsigned long *ptr; - - user_addr = vm_mmap(NULL, 0, PAGE_SIZE, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_ANONYMOUS | MAP_PRIVATE, 0); - if (user_addr >= TASK_SIZE) { - pr_warn("Failed to allocate user memory\n"); - return; - } - - if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) { - pr_warn("copy_to_user failed\n"); - vm_munmap(user_addr, PAGE_SIZE); - return; - } - - ptr = (unsigned long *)user_addr; - - pr_info("attempting bad read at %p\n", ptr); - tmp = *ptr; - tmp += 0xc0dec0de; - - pr_info("attempting bad write at %p\n", ptr); - *ptr = tmp; - - vm_munmap(user_addr, PAGE_SIZE); - - break; - } - case CT_WRITE_RO: { - /* Explicitly cast away "const" for the test. */ - unsigned long *ptr = (unsigned long *)&rodata; - - pr_info("attempting bad rodata write at %p\n", ptr); - *ptr ^= 0xabcd1234; - - break; - } - case CT_WRITE_RO_AFTER_INIT: { - unsigned long *ptr = &ro_after_init; - - /* - * Verify we were written to during init. Since an Oops - * is considered a "success", a failure is to just skip the - * real test. - */ - if ((*ptr & 0xAA) != 0xAA) { - pr_info("%p was NOT written during init!?\n", ptr); - break; - } - - pr_info("attempting bad ro_after_init write at %p\n", ptr); - *ptr ^= 0xabcd1234; - - break; - } - case CT_WRITE_KERN: { - size_t size; - unsigned char *ptr; - - size = (unsigned long)do_overwritten - - (unsigned long)do_nothing; - ptr = (unsigned char *)do_overwritten; - - pr_info("attempting bad %zu byte write at %p\n", size, ptr); - memcpy(ptr, (unsigned char *)do_nothing, size); - flush_icache_range((unsigned long)ptr, - (unsigned long)(ptr + size)); - - do_overwritten(); - break; - } - case CT_WRAP_ATOMIC: { - atomic_t under = ATOMIC_INIT(INT_MIN); - atomic_t over = ATOMIC_INIT(INT_MAX); - - pr_info("attempting atomic underflow\n"); - atomic_dec(&under); - pr_info("attempting atomic overflow\n"); - atomic_inc(&over); - - return; - } - case CT_NONE: - default: - break; - } - -} - -static void lkdtm_handler(void) -{ - unsigned long flags; - bool do_it = false; - - spin_lock_irqsave(&count_lock, flags); - count--; - pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", - cp_name_to_str(cpoint), cp_type_to_str(cptype), count); - - if (count == 0) { - do_it = true; - count = cpoint_count; - } - spin_unlock_irqrestore(&count_lock, flags); - - if (do_it) - lkdtm_do_action(cptype); -} - -static int lkdtm_register_cpoint(enum cname which) -{ - int ret; - - cpoint = CN_INVALID; - if (lkdtm.entry != NULL) - unregister_jprobe(&lkdtm); - - switch (which) { - case CN_DIRECT: - lkdtm_do_action(cptype); - return 0; - case CN_INT_HARDWARE_ENTRY: - lkdtm.kp.symbol_name = "do_IRQ"; - lkdtm.entry = (kprobe_opcode_t*) jp_do_irq; - break; - case CN_INT_HW_IRQ_EN: - lkdtm.kp.symbol_name = "handle_IRQ_event"; - lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event; - break; - case CN_INT_TASKLET_ENTRY: - lkdtm.kp.symbol_name = "tasklet_action"; - lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action; - break; - case CN_FS_DEVRW: - lkdtm.kp.symbol_name = "ll_rw_block"; - lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block; - break; - case CN_MEM_SWAPOUT: - lkdtm.kp.symbol_name = "shrink_inactive_list"; - lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list; - break; - case CN_TIMERADD: - lkdtm.kp.symbol_name = "hrtimer_start"; - lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start; - break; - case CN_SCSI_DISPATCH_CMD: - lkdtm.kp.symbol_name = "scsi_dispatch_cmd"; - lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd; - break; - case CN_IDE_CORE_CP: -#ifdef CONFIG_IDE - lkdtm.kp.symbol_name = "generic_ide_ioctl"; - lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl; -#else - pr_info("Crash point not available\n"); - return -EINVAL; -#endif - break; - default: - pr_info("Invalid Crash Point\n"); - return -EINVAL; - } - - cpoint = which; - if ((ret = register_jprobe(&lkdtm)) < 0) { - pr_info("Couldn't register jprobe\n"); - cpoint = CN_INVALID; - } - - return ret; -} - -static ssize_t do_register_entry(enum cname which, struct file *f, - const char __user *user_buf, size_t count, loff_t *off) -{ - 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); - - cptype = parse_cp_type(buf, count); - free_page((unsigned long) buf); - - if (cptype == CT_NONE) - return -EINVAL; - - err = lkdtm_register_cpoint(which); - if (err < 0) - return err; - - *off += count; - - return count; -} - -/* 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(cp_type); i++) - n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]); - 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; -} - - -static ssize_t int_hardware_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off); -} - -static ssize_t int_hw_irq_en(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off); -} - -static ssize_t int_tasklet_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off); -} - -static ssize_t fs_devrw_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_FS_DEVRW, f, buf, count, off); -} - -static ssize_t mem_swapout_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off); -} - -static ssize_t timeradd_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_TIMERADD, f, buf, count, off); -} - -static ssize_t scsi_dispatch_cmd_entry(struct file *f, - const char __user *buf, size_t count, loff_t *off) -{ - return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off); -} - -static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf, - size_t count, loff_t *off) -{ - return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off); -} - -/* 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) -{ - enum ctype type; - 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); - - type = parse_cp_type(buf, count); - free_page((unsigned long) buf); - if (type == CT_NONE) - return -EINVAL; - - pr_info("Performing direct entry %s\n", cp_type_to_str(type)); - lkdtm_do_action(type); - *off += count; - - return count; -} - -struct crash_entry { - const char *name; - const struct file_operations fops; -}; - -static const struct crash_entry crash_entries[] = { - {"DIRECT", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = direct_entry} }, - {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = int_hardware_entry} }, - {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = int_hw_irq_en} }, - {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = int_tasklet_entry} }, - {"FS_DEVRW", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = fs_devrw_entry} }, - {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = mem_swapout_entry} }, - {"TIMERADD", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = timeradd_entry} }, - {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = scsi_dispatch_cmd_entry} }, - {"IDE_CORE_CP", {.read = lkdtm_debugfs_read, - .llseek = generic_file_llseek, - .open = lkdtm_debugfs_open, - .write = ide_core_cp_entry} }, -}; - -static struct dentry *lkdtm_debugfs_root; - -static int __init lkdtm_module_init(void) -{ - int ret = -EINVAL; - int n_debugfs_entries = 1; /* Assume only the direct entry */ - int i; - - /* Make sure we can write to __ro_after_init values during __init */ - ro_after_init |= 0xAA; - - /* 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; - } - -#ifdef CONFIG_KPROBES - n_debugfs_entries = ARRAY_SIZE(crash_entries); -#endif - - for (i = 0; i < n_debugfs_entries; i++) { - const struct crash_entry *cur = &crash_entries[i]; - struct dentry *de; - - de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, - NULL, &cur->fops); - if (de == NULL) { - pr_err("could not create %s\n", cur->name); - goto out_err; - } - } - - if (lkdtm_parse_commandline() == -EINVAL) { - pr_info("Invalid command\n"); - goto out_err; - } - - if (cpoint != CN_INVALID && cptype != CT_NONE) { - ret = lkdtm_register_cpoint(cpoint); - if (ret < 0) { - pr_info("Invalid crash point %d\n", cpoint); - goto out_err; - } - pr_info("Crash point %s of type %s registered\n", - cpoint_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); - - unregister_jprobe(&lkdtm); - pr_info("Crash point unregistered\n"); -} - -module_init(lkdtm_module_init); -module_exit(lkdtm_module_exit); - -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("Kprobe module for testing crash dumps"); diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c new file mode 100644 index 000000000000..0a5cbbe12452 --- /dev/null +++ b/drivers/misc/lkdtm_core.c @@ -0,0 +1,1023 @@ +/* + * Kprobe module for testing crash dumps + * + * 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 + * + * This module induces system failures at predefined crashpoints to + * evaluate the reliability of crash dumps obtained using different dumping + * solutions. + * + * It is adapted from the Linux Kernel Dump Test Tool by + * Fernando Luis Vazquez Cao + * + * Debugfs support added by Simon Kagstrom + * + * See Documentation/fault-injection/provoke-crashes.txt for instructions + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_IDE +#include +#endif + +/* + * Make sure our attempts to over run the kernel stack doesn't trigger + * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we + * recurse past the end of THREAD_SIZE by default. + */ +#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0) +#define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2) +#else +#define REC_STACK_SIZE (THREAD_SIZE / 8) +#endif +#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2) + +#define DEFAULT_COUNT 10 +#define EXEC_SIZE 64 + +enum cname { + CN_INVALID, + CN_INT_HARDWARE_ENTRY, + CN_INT_HW_IRQ_EN, + CN_INT_TASKLET_ENTRY, + CN_FS_DEVRW, + CN_MEM_SWAPOUT, + CN_TIMERADD, + CN_SCSI_DISPATCH_CMD, + CN_IDE_CORE_CP, + CN_DIRECT, +}; + +enum ctype { + CT_NONE, + CT_PANIC, + CT_BUG, + CT_WARNING, + CT_EXCEPTION, + CT_LOOP, + CT_OVERFLOW, + CT_CORRUPT_STACK, + CT_UNALIGNED_LOAD_STORE_WRITE, + CT_OVERWRITE_ALLOCATION, + CT_WRITE_AFTER_FREE, + CT_READ_AFTER_FREE, + CT_WRITE_BUDDY_AFTER_FREE, + CT_READ_BUDDY_AFTER_FREE, + CT_SOFTLOCKUP, + CT_HARDLOCKUP, + CT_SPINLOCKUP, + CT_HUNG_TASK, + CT_EXEC_DATA, + CT_EXEC_STACK, + CT_EXEC_KMALLOC, + CT_EXEC_VMALLOC, + CT_EXEC_USERSPACE, + CT_ACCESS_USERSPACE, + CT_WRITE_RO, + CT_WRITE_RO_AFTER_INIT, + CT_WRITE_KERN, + CT_WRAP_ATOMIC +}; + +static char* cp_name[] = { + "INT_HARDWARE_ENTRY", + "INT_HW_IRQ_EN", + "INT_TASKLET_ENTRY", + "FS_DEVRW", + "MEM_SWAPOUT", + "TIMERADD", + "SCSI_DISPATCH_CMD", + "IDE_CORE_CP", + "DIRECT", +}; + +static char* cp_type[] = { + "PANIC", + "BUG", + "WARNING", + "EXCEPTION", + "LOOP", + "OVERFLOW", + "CORRUPT_STACK", + "UNALIGNED_LOAD_STORE_WRITE", + "OVERWRITE_ALLOCATION", + "WRITE_AFTER_FREE", + "READ_AFTER_FREE", + "WRITE_BUDDY_AFTER_FREE", + "READ_BUDDY_AFTER_FREE", + "SOFTLOCKUP", + "HARDLOCKUP", + "SPINLOCKUP", + "HUNG_TASK", + "EXEC_DATA", + "EXEC_STACK", + "EXEC_KMALLOC", + "EXEC_VMALLOC", + "EXEC_USERSPACE", + "ACCESS_USERSPACE", + "WRITE_RO", + "WRITE_RO_AFTER_INIT", + "WRITE_KERN", + "WRAP_ATOMIC" +}; + +static struct jprobe lkdtm; + +static int lkdtm_parse_commandline(void); +static void lkdtm_handler(void); + +static char* cpoint_name; +static char* cpoint_type; +static int cpoint_count = DEFAULT_COUNT; +static int recur_count = REC_NUM_DEFAULT; + +static enum cname cpoint = CN_INVALID; +static enum ctype cptype = CT_NONE; +static int count = DEFAULT_COUNT; +static DEFINE_SPINLOCK(count_lock); +static DEFINE_SPINLOCK(lock_me_up); + +static u8 data_area[EXEC_SIZE]; + +static const unsigned long rodata = 0xAA55AA55; +static unsigned long ro_after_init __ro_after_init = 0x55AA5500; + +module_param(recur_count, int, 0644); +MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test"); +module_param(cpoint_name, charp, 0444); +MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed"); +module_param(cpoint_type, charp, 0444); +MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ + "hitting the crash point"); +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"); + +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 + +/* Return the crashpoint number or NONE if the name is invalid */ +static enum ctype parse_cp_type(const char *what, size_t count) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cp_type); i++) { + if (!strcmp(what, cp_type[i])) + return i + 1; + } + + return CT_NONE; +} + +static const char *cp_type_to_str(enum ctype type) +{ + if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type)) + return "None"; + + return cp_type[type - 1]; +} + +static const char *cp_name_to_str(enum cname name) +{ + if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name)) + return "INVALID"; + + return cp_name[name - 1]; +} + + +static int lkdtm_parse_commandline(void) +{ + int i; + unsigned long flags; + + if (cpoint_count < 1 || recur_count < 1) + return -EINVAL; + + spin_lock_irqsave(&count_lock, flags); + count = cpoint_count; + spin_unlock_irqrestore(&count_lock, flags); + + /* No special parameters */ + if (!cpoint_type && !cpoint_name) + return 0; + + /* Neither or both of these need to be set */ + if (!cpoint_type || !cpoint_name) + return -EINVAL; + + cptype = parse_cp_type(cpoint_type, strlen(cpoint_type)); + if (cptype == CT_NONE) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(cp_name); i++) { + if (!strcmp(cpoint_name, cp_name[i])) { + cpoint = i + 1; + return 0; + } + } + + /* Could not find a valid crash point */ + return -EINVAL; +} + +static int recursive_loop(int remaining) +{ + char buf[REC_STACK_SIZE]; + + /* Make sure compiler does not optimize this away. */ + memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE); + if (!remaining) + return 0; + else + return recursive_loop(remaining - 1); +} + +static void do_nothing(void) +{ + return; +} + +/* Must immediately follow do_nothing for size calculuations to work out. */ +static void do_overwritten(void) +{ + pr_info("do_overwritten wasn't overwritten!\n"); + return; +} + +static noinline void corrupt_stack(void) +{ + /* Use default char array length that triggers stack protection. */ + char data[8]; + + memset((void *)data, 0, 64); +} + +static void noinline execute_location(void *dst) +{ + void (*func)(void) = dst; + + pr_info("attempting ok execution at %p\n", do_nothing); + do_nothing(); + + memcpy(dst, do_nothing, EXEC_SIZE); + flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); + pr_info("attempting bad execution at %p\n", func); + func(); +} + +static void execute_user_location(void *dst) +{ + /* Intentionally crossing kernel/user memory boundary. */ + void (*func)(void) = dst; + + pr_info("attempting ok execution at %p\n", do_nothing); + do_nothing(); + + if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE)) + return; + flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); + pr_info("attempting bad execution at %p\n", func); + func(); +} + +static void lkdtm_do_action(enum ctype which) +{ + switch (which) { + case CT_PANIC: + panic("dumptest"); + break; + case CT_BUG: + BUG(); + break; + case CT_WARNING: + WARN_ON(1); + break; + case CT_EXCEPTION: + *((int *) 0) = 0; + break; + case CT_LOOP: + for (;;) + ; + break; + case CT_OVERFLOW: + (void) recursive_loop(recur_count); + break; + case CT_CORRUPT_STACK: + corrupt_stack(); + break; + case CT_UNALIGNED_LOAD_STORE_WRITE: { + static u8 data[5] __attribute__((aligned(4))) = {1, 2, + 3, 4, 5}; + u32 *p; + u32 val = 0x12345678; + + p = (u32 *)(data + 1); + if (*p == 0) + val = 0x87654321; + *p = val; + break; + } + case CT_OVERWRITE_ALLOCATION: { + size_t len = 1020; + u32 *data = kmalloc(len, GFP_KERNEL); + + data[1024 / sizeof(u32)] = 0x12345678; + kfree(data); + break; + } + case CT_WRITE_AFTER_FREE: { + int *base, *again; + size_t len = 1024; + /* + * The slub allocator uses the first word to store the free + * pointer in some configurations. Use the middle of the + * allocation to avoid running into the freelist + */ + size_t offset = (len / sizeof(*base)) / 2; + + base = kmalloc(len, GFP_KERNEL); + pr_info("Allocated memory %p-%p\n", base, &base[offset * 2]); + pr_info("Attempting bad write to freed memory at %p\n", + &base[offset]); + kfree(base); + base[offset] = 0x0abcdef0; + /* Attempt to notice the overwrite. */ + again = kmalloc(len, GFP_KERNEL); + kfree(again); + if (again != base) + pr_info("Hmm, didn't get the same memory range.\n"); + + break; + } + case CT_READ_AFTER_FREE: { + int *base, *val, saw; + size_t len = 1024; + /* + * The slub allocator uses the first word to store the free + * pointer in some configurations. Use the middle of the + * allocation to avoid running into the freelist + */ + size_t offset = (len / sizeof(*base)) / 2; + + base = kmalloc(len, GFP_KERNEL); + if (!base) + break; + + val = kmalloc(len, GFP_KERNEL); + if (!val) { + kfree(base); + break; + } + + *val = 0x12345678; + base[offset] = *val; + pr_info("Value in memory before free: %x\n", base[offset]); + + kfree(base); + + pr_info("Attempting bad read from freed memory\n"); + saw = base[offset]; + if (saw != *val) { + /* Good! Poisoning happened, so declare a win. */ + pr_info("Memory correctly poisoned (%x)\n", saw); + BUG(); + } + pr_info("Memory was not poisoned\n"); + + kfree(val); + break; + } + case CT_WRITE_BUDDY_AFTER_FREE: { + unsigned long p = __get_free_page(GFP_KERNEL); + if (!p) + break; + pr_info("Writing to the buddy page before free\n"); + memset((void *)p, 0x3, PAGE_SIZE); + free_page(p); + schedule(); + pr_info("Attempting bad write to the buddy page after free\n"); + memset((void *)p, 0x78, PAGE_SIZE); + /* Attempt to notice the overwrite. */ + p = __get_free_page(GFP_KERNEL); + free_page(p); + schedule(); + + break; + } + case CT_READ_BUDDY_AFTER_FREE: { + unsigned long p = __get_free_page(GFP_KERNEL); + int saw, *val; + int *base; + + if (!p) + break; + + val = kmalloc(1024, GFP_KERNEL); + if (!val) { + free_page(p); + break; + } + + base = (int *)p; + + *val = 0x12345678; + base[0] = *val; + pr_info("Value in memory before free: %x\n", base[0]); + free_page(p); + pr_info("Attempting to read from freed memory\n"); + saw = base[0]; + if (saw != *val) { + /* Good! Poisoning happened, so declare a win. */ + pr_info("Memory correctly poisoned (%x)\n", saw); + BUG(); + } + pr_info("Buddy page was not poisoned\n"); + + kfree(val); + break; + } + case CT_SOFTLOCKUP: + preempt_disable(); + for (;;) + cpu_relax(); + break; + case CT_HARDLOCKUP: + local_irq_disable(); + for (;;) + cpu_relax(); + break; + case CT_SPINLOCKUP: + /* Must be called twice to trigger. */ + spin_lock(&lock_me_up); + /* Let sparse know we intended to exit holding the lock. */ + __release(&lock_me_up); + break; + case CT_HUNG_TASK: + set_current_state(TASK_UNINTERRUPTIBLE); + schedule(); + break; + case CT_EXEC_DATA: + execute_location(data_area); + break; + case CT_EXEC_STACK: { + u8 stack_area[EXEC_SIZE]; + execute_location(stack_area); + break; + } + case CT_EXEC_KMALLOC: { + u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL); + execute_location(kmalloc_area); + kfree(kmalloc_area); + break; + } + case CT_EXEC_VMALLOC: { + u32 *vmalloc_area = vmalloc(EXEC_SIZE); + execute_location(vmalloc_area); + vfree(vmalloc_area); + break; + } + case CT_EXEC_USERSPACE: { + unsigned long user_addr; + + user_addr = vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (user_addr >= TASK_SIZE) { + pr_warn("Failed to allocate user memory\n"); + return; + } + execute_user_location((void *)user_addr); + vm_munmap(user_addr, PAGE_SIZE); + break; + } + case CT_ACCESS_USERSPACE: { + unsigned long user_addr, tmp = 0; + unsigned long *ptr; + + user_addr = vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (user_addr >= TASK_SIZE) { + pr_warn("Failed to allocate user memory\n"); + return; + } + + if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) { + pr_warn("copy_to_user failed\n"); + vm_munmap(user_addr, PAGE_SIZE); + return; + } + + ptr = (unsigned long *)user_addr; + + pr_info("attempting bad read at %p\n", ptr); + tmp = *ptr; + tmp += 0xc0dec0de; + + pr_info("attempting bad write at %p\n", ptr); + *ptr = tmp; + + vm_munmap(user_addr, PAGE_SIZE); + + break; + } + case CT_WRITE_RO: { + /* Explicitly cast away "const" for the test. */ + unsigned long *ptr = (unsigned long *)&rodata; + + pr_info("attempting bad rodata write at %p\n", ptr); + *ptr ^= 0xabcd1234; + + break; + } + case CT_WRITE_RO_AFTER_INIT: { + unsigned long *ptr = &ro_after_init; + + /* + * Verify we were written to during init. Since an Oops + * is considered a "success", a failure is to just skip the + * real test. + */ + if ((*ptr & 0xAA) != 0xAA) { + pr_info("%p was NOT written during init!?\n", ptr); + break; + } + + pr_info("attempting bad ro_after_init write at %p\n", ptr); + *ptr ^= 0xabcd1234; + + break; + } + case CT_WRITE_KERN: { + size_t size; + unsigned char *ptr; + + size = (unsigned long)do_overwritten - + (unsigned long)do_nothing; + ptr = (unsigned char *)do_overwritten; + + pr_info("attempting bad %zu byte write at %p\n", size, ptr); + memcpy(ptr, (unsigned char *)do_nothing, size); + flush_icache_range((unsigned long)ptr, + (unsigned long)(ptr + size)); + + do_overwritten(); + break; + } + case CT_WRAP_ATOMIC: { + atomic_t under = ATOMIC_INIT(INT_MIN); + atomic_t over = ATOMIC_INIT(INT_MAX); + + pr_info("attempting atomic underflow\n"); + atomic_dec(&under); + pr_info("attempting atomic overflow\n"); + atomic_inc(&over); + + return; + } + case CT_NONE: + default: + break; + } + +} + +static void lkdtm_handler(void) +{ + unsigned long flags; + bool do_it = false; + + spin_lock_irqsave(&count_lock, flags); + count--; + pr_info("Crash point %s of type %s hit, trigger in %d rounds\n", + cp_name_to_str(cpoint), cp_type_to_str(cptype), count); + + if (count == 0) { + do_it = true; + count = cpoint_count; + } + spin_unlock_irqrestore(&count_lock, flags); + + if (do_it) + lkdtm_do_action(cptype); +} + +static int lkdtm_register_cpoint(enum cname which) +{ + int ret; + + cpoint = CN_INVALID; + if (lkdtm.entry != NULL) + unregister_jprobe(&lkdtm); + + switch (which) { + case CN_DIRECT: + lkdtm_do_action(cptype); + return 0; + case CN_INT_HARDWARE_ENTRY: + lkdtm.kp.symbol_name = "do_IRQ"; + lkdtm.entry = (kprobe_opcode_t*) jp_do_irq; + break; + case CN_INT_HW_IRQ_EN: + lkdtm.kp.symbol_name = "handle_IRQ_event"; + lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event; + break; + case CN_INT_TASKLET_ENTRY: + lkdtm.kp.symbol_name = "tasklet_action"; + lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action; + break; + case CN_FS_DEVRW: + lkdtm.kp.symbol_name = "ll_rw_block"; + lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block; + break; + case CN_MEM_SWAPOUT: + lkdtm.kp.symbol_name = "shrink_inactive_list"; + lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list; + break; + case CN_TIMERADD: + lkdtm.kp.symbol_name = "hrtimer_start"; + lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start; + break; + case CN_SCSI_DISPATCH_CMD: + lkdtm.kp.symbol_name = "scsi_dispatch_cmd"; + lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd; + break; + case CN_IDE_CORE_CP: +#ifdef CONFIG_IDE + lkdtm.kp.symbol_name = "generic_ide_ioctl"; + lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl; +#else + pr_info("Crash point not available\n"); + return -EINVAL; +#endif + break; + default: + pr_info("Invalid Crash Point\n"); + return -EINVAL; + } + + cpoint = which; + if ((ret = register_jprobe(&lkdtm)) < 0) { + pr_info("Couldn't register jprobe\n"); + cpoint = CN_INVALID; + } + + return ret; +} + +static ssize_t do_register_entry(enum cname which, struct file *f, + const char __user *user_buf, size_t count, loff_t *off) +{ + 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); + + cptype = parse_cp_type(buf, count); + free_page((unsigned long) buf); + + if (cptype == CT_NONE) + return -EINVAL; + + err = lkdtm_register_cpoint(which); + if (err < 0) + return err; + + *off += count; + + return count; +} + +/* 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(cp_type); i++) + n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]); + 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; +} + + +static ssize_t int_hardware_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off); +} + +static ssize_t int_hw_irq_en(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off); +} + +static ssize_t int_tasklet_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off); +} + +static ssize_t fs_devrw_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_FS_DEVRW, f, buf, count, off); +} + +static ssize_t mem_swapout_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off); +} + +static ssize_t timeradd_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_TIMERADD, f, buf, count, off); +} + +static ssize_t scsi_dispatch_cmd_entry(struct file *f, + const char __user *buf, size_t count, loff_t *off) +{ + return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off); +} + +static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off); +} + +/* 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) +{ + enum ctype type; + 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); + + type = parse_cp_type(buf, count); + free_page((unsigned long) buf); + if (type == CT_NONE) + return -EINVAL; + + pr_info("Performing direct entry %s\n", cp_type_to_str(type)); + lkdtm_do_action(type); + *off += count; + + return count; +} + +struct crash_entry { + const char *name; + const struct file_operations fops; +}; + +static const struct crash_entry crash_entries[] = { + {"DIRECT", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = direct_entry} }, + {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = int_hardware_entry} }, + {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = int_hw_irq_en} }, + {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = int_tasklet_entry} }, + {"FS_DEVRW", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = fs_devrw_entry} }, + {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = mem_swapout_entry} }, + {"TIMERADD", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = timeradd_entry} }, + {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = scsi_dispatch_cmd_entry} }, + {"IDE_CORE_CP", {.read = lkdtm_debugfs_read, + .llseek = generic_file_llseek, + .open = lkdtm_debugfs_open, + .write = ide_core_cp_entry} }, +}; + +static struct dentry *lkdtm_debugfs_root; + +static int __init lkdtm_module_init(void) +{ + int ret = -EINVAL; + int n_debugfs_entries = 1; /* Assume only the direct entry */ + int i; + + /* Make sure we can write to __ro_after_init values during __init */ + ro_after_init |= 0xAA; + + /* 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; + } + +#ifdef CONFIG_KPROBES + n_debugfs_entries = ARRAY_SIZE(crash_entries); +#endif + + for (i = 0; i < n_debugfs_entries; i++) { + const struct crash_entry *cur = &crash_entries[i]; + struct dentry *de; + + de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, + NULL, &cur->fops); + if (de == NULL) { + pr_err("could not create %s\n", cur->name); + goto out_err; + } + } + + if (lkdtm_parse_commandline() == -EINVAL) { + pr_info("Invalid command\n"); + goto out_err; + } + + if (cpoint != CN_INVALID && cptype != CT_NONE) { + ret = lkdtm_register_cpoint(cpoint); + if (ret < 0) { + pr_info("Invalid crash point %d\n", cpoint); + goto out_err; + } + pr_info("Crash point %s of type %s registered\n", + cpoint_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); + + unregister_jprobe(&lkdtm); + pr_info("Crash point unregistered\n"); +} + +module_init(lkdtm_module_init); +module_exit(lkdtm_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Kprobe module for testing crash dumps"); -- cgit v1.2.3 From 426f3a53d4a1ffbe228f268e5c4af148686b7346 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 3 Jun 2016 11:16:32 -0700 Subject: lkdtm: clean up after rename This cleans up comments a bit to improve readability, adjusts the name of the module after the source file renaming, and corrects the MAINTAINERS for the upcoming lkdtm files. Signed-off-by: Kees Cook --- MAINTAINERS | 2 +- drivers/misc/lkdtm_core.c | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 2ebe195951af..977504e81f33 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6954,7 +6954,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching.git LINUX KERNEL DUMP TEST MODULE (LKDTM) M: Kees Cook S: Maintained -F: drivers/misc/lkdtm.c +F: drivers/misc/lkdtm* LLC (802.2) M: Arnaldo Carvalho de Melo diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 0a5cbbe12452..605050c60f10 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -1,5 +1,9 @@ /* - * Kprobe module for testing crash dumps + * 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 @@ -19,10 +23,6 @@ * * Author: Ankita Garg * - * This module induces system failures at predefined crashpoints to - * evaluate the reliability of crash dumps obtained using different dumping - * solutions. - * * It is adapted from the Linux Kernel Dump Test Tool by * Fernando Luis Vazquez Cao * @@ -30,7 +30,7 @@ * * See Documentation/fault-injection/provoke-crashes.txt for instructions */ -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#define pr_fmt(fmt) "lkdtm: " fmt #include #include -- cgit v1.2.3 From 9a49a528dcf3c2022ff89f700d5d0345b9abf288 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 22 Feb 2016 14:09:29 -0800 Subject: lkdtm: add function for testing .rodata section This adds a function that lives in the .rodata section. The section flags are corrected using objcopy since there is no way with gcc to declare section flags in an architecture-agnostic way. Signed-off-by: Kees Cook --- drivers/misc/Makefile | 8 ++++++++ drivers/misc/lkdtm.h | 6 ++++++ drivers/misc/lkdtm_core.c | 24 +++++++++++++++++------- drivers/misc/lkdtm_rodata.c | 10 ++++++++++ 4 files changed, 41 insertions(+), 7 deletions(-) create mode 100644 drivers/misc/lkdtm.h create mode 100644 drivers/misc/lkdtm_rodata.c diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index c3cb6ad8cc37..7d45ed4a1549 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -59,3 +59,11 @@ obj-$(CONFIG_CXL_BASE) += cxl/ obj-$(CONFIG_PANEL) += panel.o lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o +lkdtm-$(CONFIG_LKDTM) += lkdtm_rodata_objcopy.o + +OBJCOPYFLAGS := +OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \ + --set-section-flags .text=alloc,readonly \ + --rename-section .text=.rodata +$(obj)/lkdtm_rodata_objcopy.o: $(obj)/lkdtm_rodata.o + $(call if_changed,objcopy) diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h new file mode 100644 index 000000000000..9531fa3be4c3 --- /dev/null +++ b/drivers/misc/lkdtm.h @@ -0,0 +1,6 @@ +#ifndef __LKDTM_H +#define __LKDTM_H + +void lkdtm_rodata_do_nothing(void); + +#endif diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 605050c60f10..187cd9b63e9a 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -52,6 +52,8 @@ #include #endif +#include "lkdtm.h" + /* * Make sure our attempts to over run the kernel stack doesn't trigger * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we @@ -103,6 +105,7 @@ enum ctype { CT_EXEC_STACK, CT_EXEC_KMALLOC, CT_EXEC_VMALLOC, + CT_EXEC_RODATA, CT_EXEC_USERSPACE, CT_ACCESS_USERSPACE, CT_WRITE_RO, @@ -145,6 +148,7 @@ static char* cp_type[] = { "EXEC_STACK", "EXEC_KMALLOC", "EXEC_VMALLOC", + "EXEC_RODATA", "EXEC_USERSPACE", "ACCESS_USERSPACE", "WRITE_RO", @@ -346,15 +350,18 @@ static noinline void corrupt_stack(void) memset((void *)data, 0, 64); } -static void noinline execute_location(void *dst) +static noinline void execute_location(void *dst, bool write) { void (*func)(void) = dst; pr_info("attempting ok execution at %p\n", do_nothing); do_nothing(); - memcpy(dst, do_nothing, EXEC_SIZE); - flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE); + if (write) { + memcpy(dst, do_nothing, EXEC_SIZE); + flush_icache_range((unsigned long)dst, + (unsigned long)dst + EXEC_SIZE); + } pr_info("attempting bad execution at %p\n", func); func(); } @@ -551,25 +558,28 @@ static void lkdtm_do_action(enum ctype which) schedule(); break; case CT_EXEC_DATA: - execute_location(data_area); + execute_location(data_area, true); break; case CT_EXEC_STACK: { u8 stack_area[EXEC_SIZE]; - execute_location(stack_area); + execute_location(stack_area, true); break; } case CT_EXEC_KMALLOC: { u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL); - execute_location(kmalloc_area); + execute_location(kmalloc_area, true); kfree(kmalloc_area); break; } case CT_EXEC_VMALLOC: { u32 *vmalloc_area = vmalloc(EXEC_SIZE); - execute_location(vmalloc_area); + execute_location(vmalloc_area, true); vfree(vmalloc_area); break; } + case CT_EXEC_RODATA: + execute_location(lkdtm_rodata_do_nothing, false); + break; case CT_EXEC_USERSPACE: { unsigned long user_addr; diff --git a/drivers/misc/lkdtm_rodata.c b/drivers/misc/lkdtm_rodata.c new file mode 100644 index 000000000000..4d0d851f02b9 --- /dev/null +++ b/drivers/misc/lkdtm_rodata.c @@ -0,0 +1,10 @@ +/* + * This includes functions that are meant to live entirely in .rodata + * (via objcopy tricks), to validate the non-executability of .rodata. + */ +#include + +void lkdtm_rodata_do_nothing(void) +{ + /* Does nothing. We just want an architecture agnostic "return". */ +} -- cgit v1.2.3 From aa981a665d587a19be869ce7f3cb7232f8588dd8 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 3 Jun 2016 12:06:52 -0700 Subject: lkdtm: add usercopy tests This adds test to detect copy_to_user/copy_from_user problems that are protected by PAX_USERCOPY (and will be protected by HARDENED_USERCOPY). Explicitly tests both "to" and "from" directions of heap object size problems, heap object markings and, stack frame misalignment. Signed-off-by: Kees Cook --- drivers/misc/lkdtm_core.c | 275 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 273 insertions(+), 2 deletions(-) diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 187cd9b63e9a..3fe4b5dee955 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -111,7 +111,14 @@ enum ctype { CT_WRITE_RO, CT_WRITE_RO_AFTER_INIT, CT_WRITE_KERN, - CT_WRAP_ATOMIC + CT_WRAP_ATOMIC, + CT_USERCOPY_HEAP_SIZE_TO, + CT_USERCOPY_HEAP_SIZE_FROM, + CT_USERCOPY_HEAP_FLAG_TO, + CT_USERCOPY_HEAP_FLAG_FROM, + CT_USERCOPY_STACK_FRAME_TO, + CT_USERCOPY_STACK_FRAME_FROM, + CT_USERCOPY_STACK_BEYOND, }; static char* cp_name[] = { @@ -154,7 +161,14 @@ static char* cp_type[] = { "WRITE_RO", "WRITE_RO_AFTER_INIT", "WRITE_KERN", - "WRAP_ATOMIC" + "WRAP_ATOMIC", + "USERCOPY_HEAP_SIZE_TO", + "USERCOPY_HEAP_SIZE_FROM", + "USERCOPY_HEAP_FLAG_TO", + "USERCOPY_HEAP_FLAG_FROM", + "USERCOPY_STACK_FRAME_TO", + "USERCOPY_STACK_FRAME_FROM", + "USERCOPY_STACK_BEYOND", }; static struct jprobe lkdtm; @@ -166,6 +180,8 @@ static char* cpoint_name; static char* cpoint_type; static int cpoint_count = DEFAULT_COUNT; static int recur_count = REC_NUM_DEFAULT; +static int alloc_size = 1024; +static size_t cache_size; static enum cname cpoint = CN_INVALID; static enum ctype cptype = CT_NONE; @@ -174,7 +190,9 @@ static DEFINE_SPINLOCK(count_lock); static DEFINE_SPINLOCK(lock_me_up); static u8 data_area[EXEC_SIZE]; +static struct kmem_cache *bad_cache; +static const unsigned char test_text[] = "This is a test.\n"; static const unsigned long rodata = 0xAA55AA55; static unsigned long ro_after_init __ro_after_init = 0x55AA5500; @@ -188,6 +206,9 @@ MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\ 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"); +module_param(alloc_size, int, 0644); +MODULE_PARM_DESC(alloc_size, " Size of allocation for user copy tests "\ + "(from 1 to PAGE_SIZE)"); static unsigned int jp_do_irq(unsigned int irq) { @@ -381,6 +402,228 @@ static void execute_user_location(void *dst) func(); } +/* + * Instead of adding -Wno-return-local-addr, just pass the stack address + * through a function to obfuscate it from the compiler. + */ +static noinline unsigned char *trick_compiler(unsigned char *stack) +{ + return stack + 0; +} + +static noinline unsigned char *do_usercopy_stack_callee(int value) +{ + unsigned char buf[32]; + int i; + + /* Exercise stack to avoid everything living in registers. */ + for (i = 0; i < sizeof(buf); i++) { + buf[i] = value & 0xff; + } + + return trick_compiler(buf); +} + +static noinline void do_usercopy_stack(bool to_user, bool bad_frame) +{ + unsigned long user_addr; + unsigned char good_stack[32]; + unsigned char *bad_stack; + int i; + + /* Exercise stack to avoid everything living in registers. */ + for (i = 0; i < sizeof(good_stack); i++) + good_stack[i] = test_text[i % sizeof(test_text)]; + + /* This is a pointer to outside our current stack frame. */ + if (bad_frame) { + bad_stack = do_usercopy_stack_callee(alloc_size); + } else { + /* Put start address just inside stack. */ + bad_stack = task_stack_page(current) + THREAD_SIZE; + bad_stack -= sizeof(unsigned long); + } + + user_addr = vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (user_addr >= TASK_SIZE) { + pr_warn("Failed to allocate user memory\n"); + return; + } + + if (to_user) { + pr_info("attempting good copy_to_user of local stack\n"); + if (copy_to_user((void __user *)user_addr, good_stack, + sizeof(good_stack))) { + pr_warn("copy_to_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_to_user of distant stack\n"); + if (copy_to_user((void __user *)user_addr, bad_stack, + sizeof(good_stack))) { + pr_warn("copy_to_user failed, but lacked Oops\n"); + goto free_user; + } + } else { + /* + * There isn't a safe way to not be protected by usercopy + * if we're going to write to another thread's stack. + */ + if (!bad_frame) + goto free_user; + + pr_info("attempting good copy_from_user of local stack\n"); + if (copy_from_user(good_stack, (void __user *)user_addr, + sizeof(good_stack))) { + pr_warn("copy_from_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_from_user of distant stack\n"); + if (copy_from_user(bad_stack, (void __user *)user_addr, + sizeof(good_stack))) { + pr_warn("copy_from_user failed, but lacked Oops\n"); + goto free_user; + } + } + +free_user: + vm_munmap(user_addr, PAGE_SIZE); +} + +static void do_usercopy_heap_size(bool to_user) +{ + unsigned long user_addr; + unsigned char *one, *two; + size_t size = clamp_t(int, alloc_size, 1, PAGE_SIZE); + + one = kmalloc(size, GFP_KERNEL); + two = kmalloc(size, GFP_KERNEL); + if (!one || !two) { + pr_warn("Failed to allocate kernel memory\n"); + goto free_kernel; + } + + user_addr = vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (user_addr >= TASK_SIZE) { + pr_warn("Failed to allocate user memory\n"); + goto free_kernel; + } + + memset(one, 'A', size); + memset(two, 'B', size); + + if (to_user) { + pr_info("attempting good copy_to_user of correct size\n"); + if (copy_to_user((void __user *)user_addr, one, size)) { + pr_warn("copy_to_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_to_user of too large size\n"); + if (copy_to_user((void __user *)user_addr, one, 2 * size)) { + pr_warn("copy_to_user failed, but lacked Oops\n"); + goto free_user; + } + } else { + pr_info("attempting good copy_from_user of correct size\n"); + if (copy_from_user(one, (void __user *)user_addr, + size)) { + pr_warn("copy_from_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_from_user of too large size\n"); + if (copy_from_user(one, (void __user *)user_addr, 2 * size)) { + pr_warn("copy_from_user failed, but lacked Oops\n"); + goto free_user; + } + } + +free_user: + vm_munmap(user_addr, PAGE_SIZE); +free_kernel: + kfree(one); + kfree(two); +} + +static void do_usercopy_heap_flag(bool to_user) +{ + unsigned long user_addr; + unsigned char *good_buf = NULL; + unsigned char *bad_buf = NULL; + + /* Make sure cache was prepared. */ + if (!bad_cache) { + pr_warn("Failed to allocate kernel cache\n"); + return; + } + + /* + * Allocate one buffer from each cache (kmalloc will have the + * SLAB_USERCOPY flag already, but "bad_cache" won't). + */ + good_buf = kmalloc(cache_size, GFP_KERNEL); + bad_buf = kmem_cache_alloc(bad_cache, GFP_KERNEL); + if (!good_buf || !bad_buf) { + pr_warn("Failed to allocate buffers from caches\n"); + goto free_alloc; + } + + /* Allocate user memory we'll poke at. */ + user_addr = vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (user_addr >= TASK_SIZE) { + pr_warn("Failed to allocate user memory\n"); + goto free_alloc; + } + + memset(good_buf, 'A', cache_size); + memset(bad_buf, 'B', cache_size); + + if (to_user) { + pr_info("attempting good copy_to_user with SLAB_USERCOPY\n"); + if (copy_to_user((void __user *)user_addr, good_buf, + cache_size)) { + pr_warn("copy_to_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_to_user w/o SLAB_USERCOPY\n"); + if (copy_to_user((void __user *)user_addr, bad_buf, + cache_size)) { + pr_warn("copy_to_user failed, but lacked Oops\n"); + goto free_user; + } + } else { + pr_info("attempting good copy_from_user with SLAB_USERCOPY\n"); + if (copy_from_user(good_buf, (void __user *)user_addr, + cache_size)) { + pr_warn("copy_from_user failed unexpectedly?!\n"); + goto free_user; + } + + pr_info("attempting bad copy_from_user w/o SLAB_USERCOPY\n"); + if (copy_from_user(bad_buf, (void __user *)user_addr, + cache_size)) { + pr_warn("copy_from_user failed, but lacked Oops\n"); + goto free_user; + } + } + +free_user: + vm_munmap(user_addr, PAGE_SIZE); +free_alloc: + if (bad_buf) + kmem_cache_free(bad_cache, bad_buf); + kfree(good_buf); +} + static void lkdtm_do_action(enum ctype which) { switch (which) { @@ -679,6 +922,27 @@ static void lkdtm_do_action(enum ctype which) return; } + case CT_USERCOPY_HEAP_SIZE_TO: + do_usercopy_heap_size(true); + break; + case CT_USERCOPY_HEAP_SIZE_FROM: + do_usercopy_heap_size(false); + break; + case CT_USERCOPY_HEAP_FLAG_TO: + do_usercopy_heap_flag(true); + break; + case CT_USERCOPY_HEAP_FLAG_FROM: + do_usercopy_heap_flag(false); + break; + case CT_USERCOPY_STACK_FRAME_TO: + do_usercopy_stack(true, true); + break; + case CT_USERCOPY_STACK_FRAME_FROM: + do_usercopy_stack(false, true); + break; + case CT_USERCOPY_STACK_BEYOND: + do_usercopy_stack(true, false); + break; case CT_NONE: default: break; @@ -971,6 +1235,11 @@ static int __init lkdtm_module_init(void) /* Make sure we can write to __ro_after_init values during __init */ ro_after_init |= 0xAA; + /* Prepare cache that lacks SLAB_USERCOPY flag. */ + cache_size = clamp_t(int, alloc_size, 1, PAGE_SIZE); + bad_cache = kmem_cache_create("lkdtm-no-usercopy", cache_size, 0, + 0, NULL); + /* Register debugfs interface */ lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); if (!lkdtm_debugfs_root) { @@ -1022,6 +1291,8 @@ static void __exit lkdtm_module_exit(void) { debugfs_remove_recursive(lkdtm_debugfs_root); + kmem_cache_destroy(bad_cache); + unregister_jprobe(&lkdtm); pr_info("Crash point unregistered\n"); } -- cgit v1.2.3 From b54845276a969b72daa2dee1afe379847a639478 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 7 Jun 2016 14:27:02 -0700 Subject: lkdtm: split atomic test into over and underflow Each direction of the atomic wrapping should be individually testable. Signed-off-by: Kees Cook --- drivers/misc/lkdtm_core.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 3fe4b5dee955..a595a6f2615a 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -111,7 +111,8 @@ enum ctype { CT_WRITE_RO, CT_WRITE_RO_AFTER_INIT, CT_WRITE_KERN, - CT_WRAP_ATOMIC, + CT_ATOMIC_UNDERFLOW, + CT_ATOMIC_OVERFLOW, CT_USERCOPY_HEAP_SIZE_TO, CT_USERCOPY_HEAP_SIZE_FROM, CT_USERCOPY_HEAP_FLAG_TO, @@ -161,7 +162,8 @@ static char* cp_type[] = { "WRITE_RO", "WRITE_RO_AFTER_INIT", "WRITE_KERN", - "WRAP_ATOMIC", + "ATOMIC_UNDERFLOW", + "ATOMIC_OVERFLOW", "USERCOPY_HEAP_SIZE_TO", "USERCOPY_HEAP_SIZE_FROM", "USERCOPY_HEAP_FLAG_TO", @@ -911,13 +913,25 @@ static void lkdtm_do_action(enum ctype which) do_overwritten(); break; } - case CT_WRAP_ATOMIC: { + case CT_ATOMIC_UNDERFLOW: { atomic_t under = ATOMIC_INIT(INT_MIN); - atomic_t over = ATOMIC_INIT(INT_MAX); - pr_info("attempting atomic underflow\n"); + pr_info("attempting good atomic increment\n"); + atomic_inc(&under); + atomic_dec(&under); + + pr_info("attempting bad atomic underflow\n"); atomic_dec(&under); - pr_info("attempting atomic overflow\n"); + break; + } + case CT_ATOMIC_OVERFLOW: { + atomic_t over = ATOMIC_INIT(INT_MAX); + + pr_info("attempting good atomic decrement\n"); + atomic_dec(&over); + atomic_inc(&over); + + pr_info("attempting bad atomic overflow\n"); atomic_inc(&over); return; -- cgit v1.2.3