diff options
Diffstat (limited to 'drivers/misc/lkdtm/core.c')
-rw-r--r-- | drivers/misc/lkdtm/core.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c new file mode 100644 index 000000000..0772e4a47 --- /dev/null +++ b/drivers/misc/lkdtm/core.c @@ -0,0 +1,488 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 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. + * + * 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.rst 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/slab.h> +#include <linux/debugfs.h> +#include <linux/utsname.h> + +#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 int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs); +static ssize_t lkdtm_debugfs_entry(struct file *f, + const char __user *user_buf, + size_t count, loff_t *off); +# define CRASHPOINT_KPROBE(_symbol) \ + .kprobe = { \ + .symbol_name = (_symbol), \ + .pre_handler = lkdtm_kprobe_handler, \ + }, +# define CRASHPOINT_WRITE(_symbol) \ + (_symbol) ? lkdtm_debugfs_entry : direct_entry +#else +# define CRASHPOINT_KPROBE(_symbol) +# define CRASHPOINT_WRITE(_symbol) direct_entry +#endif + +/* Crash points */ +struct crashpoint { + const char *name; + const struct file_operations fops; + struct kprobe kprobe; +}; + +#define CRASHPOINT(_name, _symbol) \ + { \ + .name = _name, \ + .fops = { \ + .read = lkdtm_debugfs_read, \ + .llseek = generic_file_llseek, \ + .open = lkdtm_debugfs_open, \ + .write = CRASHPOINT_WRITE(_symbol) \ + }, \ + CRASHPOINT_KPROBE(_symbol) \ + } + +/* Define the possible places where we can trigger a crash point. */ +static struct crashpoint crashpoints[] = { + CRASHPOINT("DIRECT", NULL), +#ifdef CONFIG_KPROBES + CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"), + CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"), + CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"), + CRASHPOINT("FS_SUBMIT_BH", "submit_bh"), + CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"), + CRASHPOINT("TIMERADD", "hrtimer_start"), + CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"), +#endif +}; + +/* List of possible types for crashes that can be triggered. */ +static const struct crashtype_category *crashtype_categories[] = { + &bugs_crashtypes, + &heap_crashtypes, + &perms_crashtypes, + &refcount_crashtypes, + &usercopy_crashtypes, + &stackleak_crashtypes, + &cfi_crashtypes, + &fortify_crashtypes, +#ifdef CONFIG_PPC_64S_HASH_MMU + &powerpc_crashtypes, +#endif +}; + +/* Global kprobe entry and crashtype. */ +static struct kprobe *lkdtm_kprobe; +static struct crashpoint *lkdtm_crashpoint; +static const 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"); + +/* + * For test debug reporting when CI systems provide terse summaries. + * TODO: Remove this once reasonable reporting exists in most CI systems: + * https://lore.kernel.org/lkml/CAHk-=wiFvfkoFixTapvvyPMN9pq5G-+Dys2eSyBa1vzDGAO5+A@mail.gmail.com + */ +char *lkdtm_kernel_info; + +/* Return the crashtype number or NULL if the name is invalid */ +static const struct crashtype *find_crashtype(const char *name) +{ + int cat, idx; + + for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) { + for (idx = 0; idx < crashtype_categories[cat]->len; idx++) { + struct crashtype *crashtype; + + crashtype = &crashtype_categories[cat]->crashtypes[idx]; + if (!strcmp(name, crashtype->name)) + return crashtype; + } + } + + 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(const struct crashtype *crashtype) +{ + if (WARN_ON(!crashtype || !crashtype->func)) + return; + crashtype->func(); +} + +static int lkdtm_register_cpoint(struct crashpoint *crashpoint, + const struct crashtype *crashtype) +{ + int ret; + + /* If this doesn't have a symbol, just call immediately. */ + if (!crashpoint->kprobe.symbol_name) { + lkdtm_do_action(crashtype); + return 0; + } + + if (lkdtm_kprobe != NULL) + unregister_kprobe(lkdtm_kprobe); + + lkdtm_crashpoint = crashpoint; + lkdtm_crashtype = crashtype; + lkdtm_kprobe = &crashpoint->kprobe; + ret = register_kprobe(lkdtm_kprobe); + if (ret < 0) { + pr_info("Couldn't register kprobe %s\n", + crashpoint->kprobe.symbol_name); + lkdtm_kprobe = 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 kprobe entry points. */ +static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) +{ + unsigned long flags; + bool do_it = false; + + if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype)) + return 0; + + 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); + + return 0; +} + +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; + const 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) +{ + int n, cat, idx; + ssize_t out; + char *buf; + + buf = (char *)__get_free_page(GFP_KERNEL); + if (buf == NULL) + return -ENOMEM; + + n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n"); + + for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) { + for (idx = 0; idx < crashtype_categories[cat]->len; idx++) { + struct crashtype *crashtype; + + crashtype = &crashtype_categories[cat]->crashtypes[idx]; + n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n", + crashtype->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) +{ + const 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; +} + +#ifndef MODULE +/* + * To avoid needing to export parse_args(), just don't use this code + * when LKDTM is built as a module. + */ +struct check_cmdline_args { + const char *param; + int value; +}; + +static int lkdtm_parse_one(char *param, char *val, + const char *unused, void *arg) +{ + struct check_cmdline_args *args = arg; + + /* short circuit if we already found a value. */ + if (args->value != -ESRCH) + return 0; + if (strncmp(param, args->param, strlen(args->param)) == 0) { + bool bool_result; + int ret; + + ret = kstrtobool(val, &bool_result); + if (ret == 0) + args->value = bool_result; + } + return 0; +} + +int lkdtm_check_bool_cmdline(const char *param) +{ + char *command_line; + struct check_cmdline_args args = { + .param = param, + .value = -ESRCH, + }; + + command_line = kstrdup(saved_command_line, GFP_KERNEL); + if (!command_line) + return -ENOMEM; + + parse_args("Setting sysctl args", command_line, + NULL, 0, -1, -1, &args, lkdtm_parse_one); + + kfree(command_line); + + return args.value; +} +#endif + +static struct dentry *lkdtm_debugfs_root; + +static int __init lkdtm_module_init(void) +{ + struct crashpoint *crashpoint = NULL; + const struct crashtype *crashtype = NULL; + int ret; + 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 + + /* Common initialization. */ + lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)", + init_uts_ns.name.release, + init_uts_ns.name.machine); + + /* Handle test-specific initialization. */ + lkdtm_bugs_init(&recur_count); + lkdtm_perms_init(); + lkdtm_usercopy_init(); + lkdtm_heap_init(); + + /* Register debugfs interface */ + lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); + + /* Install debugfs trigger files. */ + for (i = 0; i < ARRAY_SIZE(crashpoints); i++) { + struct crashpoint *cur = &crashpoints[i]; + + debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur, + &cur->fops); + } + + /* 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_heap_exit(); + lkdtm_usercopy_exit(); + + if (lkdtm_kprobe != NULL) + unregister_kprobe(lkdtm_kprobe); + + kfree(lkdtm_kernel_info); + + 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"); |