/* * 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_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_KERN, }; 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", "SOFTLOCKUP", "HARDLOCKUP", "SPINLOCKUP", "HUNG_TASK", "EXEC_DATA", "EXEC_STACK", "EXEC_KMALLOC", "EXEC_VMALLOC", "EXEC_USERSPACE", "ACCESS_USERSPACE", "WRITE_RO", "WRITE_KERN", }; 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; 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 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: { size_t len = 1024; u32 *data = kmalloc(len, GFP_KERNEL); kfree(data); schedule(); memset(data, 0x78, len); 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; 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; } 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: { unsigned long *ptr; ptr = (unsigned long *)&rodata; pr_info("attempting bad 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_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; /* 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");