| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Kernel Probes (KProbes) |
| * |
| * Copyright (C) IBM Corporation, 2002, 2004 |
| * |
| * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel |
| * Probes initial implementation (includes suggestions from |
| * Rusty Russell). |
| * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with |
| * hlists and exceptions notifier as suggested by Andi Kleen. |
| * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes |
| * interface to access function arguments. |
| * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes |
| * exceptions notifier to be first on the priority list. |
| * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
| * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi |
| * <prasanna@in.ibm.com> added function-return probes. |
| */ |
| |
| #define pr_fmt(fmt) "kprobes: " fmt |
| |
| #include <linux/kprobes.h> |
| #include <linux/hash.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/stddef.h> |
| #include <linux/export.h> |
| #include <linux/kallsyms.h> |
| #include <linux/freezer.h> |
| #include <linux/seq_file.h> |
| #include <linux/debugfs.h> |
| #include <linux/sysctl.h> |
| #include <linux/kdebug.h> |
| #include <linux/memory.h> |
| #include <linux/ftrace.h> |
| #include <linux/cpu.h> |
| #include <linux/jump_label.h> |
| #include <linux/static_call.h> |
| #include <linux/perf_event.h> |
| #include <linux/execmem.h> |
| |
| #include <asm/sections.h> |
| #include <asm/cacheflush.h> |
| #include <asm/errno.h> |
| #include <linux/uaccess.h> |
| |
| #define KPROBE_HASH_BITS 6 |
| #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
| |
| #if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL) |
| #define kprobe_sysctls_init() do { } while (0) |
| #endif |
| |
| static int kprobes_initialized; |
| /* kprobe_table can be accessed by |
| * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held. |
| * Or |
| * - RCU hlist traversal under disabling preempt (breakpoint handlers) |
| */ |
| static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
| |
| /* NOTE: change this value only with 'kprobe_mutex' held */ |
| static bool kprobes_all_disarmed; |
| |
| /* This protects 'kprobe_table' and 'optimizing_list' */ |
| static DEFINE_MUTEX(kprobe_mutex); |
| static DEFINE_PER_CPU(struct kprobe *, kprobe_instance); |
| |
| kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, |
| unsigned int __unused) |
| { |
| return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); |
| } |
| |
| /* |
| * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where |
| * kprobes can not probe. |
| */ |
| static LIST_HEAD(kprobe_blacklist); |
| |
| #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
| /* |
| * 'kprobe::ainsn.insn' points to the copy of the instruction to be |
| * single-stepped. x86_64, POWER4 and above have no-exec support and |
| * stepping on the instruction on a vmalloced/kmalloced/data page |
| * is a recipe for disaster |
| */ |
| struct kprobe_insn_page { |
| struct list_head list; |
| kprobe_opcode_t *insns; /* Page of instruction slots */ |
| struct kprobe_insn_cache *cache; |
| int nused; |
| int ngarbage; |
| char slot_used[]; |
| }; |
| |
| #define KPROBE_INSN_PAGE_SIZE(slots) \ |
| (offsetof(struct kprobe_insn_page, slot_used) + \ |
| (sizeof(char) * (slots))) |
| |
| static int slots_per_page(struct kprobe_insn_cache *c) |
| { |
| return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); |
| } |
| |
| enum kprobe_slot_state { |
| SLOT_CLEAN = 0, |
| SLOT_DIRTY = 1, |
| SLOT_USED = 2, |
| }; |
| |
| void __weak *alloc_insn_page(void) |
| { |
| /* |
| * Use execmem_alloc() so this page is within +/- 2GB of where the |
| * kernel image and loaded module images reside. This is required |
| * for most of the architectures. |
| * (e.g. x86-64 needs this to handle the %rip-relative fixups.) |
| */ |
| return execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE); |
| } |
| |
| static void free_insn_page(void *page) |
| { |
| execmem_free(page); |
| } |
| |
| struct kprobe_insn_cache kprobe_insn_slots = { |
| .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), |
| .alloc = alloc_insn_page, |
| .free = free_insn_page, |
| .sym = KPROBE_INSN_PAGE_SYM, |
| .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
| .insn_size = MAX_INSN_SIZE, |
| .nr_garbage = 0, |
| }; |
| static int collect_garbage_slots(struct kprobe_insn_cache *c); |
| |
| /** |
| * __get_insn_slot() - Find a slot on an executable page for an instruction. |
| * We allocate an executable page if there's no room on existing ones. |
| */ |
| kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
| { |
| struct kprobe_insn_page *kip; |
| kprobe_opcode_t *slot = NULL; |
| |
| /* Since the slot array is not protected by rcu, we need a mutex */ |
| mutex_lock(&c->mutex); |
| retry: |
| rcu_read_lock(); |
| list_for_each_entry_rcu(kip, &c->pages, list) { |
| if (kip->nused < slots_per_page(c)) { |
| int i; |
| |
| for (i = 0; i < slots_per_page(c); i++) { |
| if (kip->slot_used[i] == SLOT_CLEAN) { |
| kip->slot_used[i] = SLOT_USED; |
| kip->nused++; |
| slot = kip->insns + (i * c->insn_size); |
| rcu_read_unlock(); |
| goto out; |
| } |
| } |
| /* kip->nused is broken. Fix it. */ |
| kip->nused = slots_per_page(c); |
| WARN_ON(1); |
| } |
| } |
| rcu_read_unlock(); |
| |
| /* If there are any garbage slots, collect it and try again. */ |
| if (c->nr_garbage && collect_garbage_slots(c) == 0) |
| goto retry; |
| |
| /* All out of space. Need to allocate a new page. */ |
| kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
| if (!kip) |
| goto out; |
| |
| kip->insns = c->alloc(); |
| if (!kip->insns) { |
| kfree(kip); |
| goto out; |
| } |
| INIT_LIST_HEAD(&kip->list); |
| memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
| kip->slot_used[0] = SLOT_USED; |
| kip->nused = 1; |
| kip->ngarbage = 0; |
| kip->cache = c; |
| list_add_rcu(&kip->list, &c->pages); |
| slot = kip->insns; |
| |
| /* Record the perf ksymbol register event after adding the page */ |
| perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns, |
| PAGE_SIZE, false, c->sym); |
| out: |
| mutex_unlock(&c->mutex); |
| return slot; |
| } |
| |
| /* Return true if all garbages are collected, otherwise false. */ |
| static bool collect_one_slot(struct kprobe_insn_page *kip, int idx) |
| { |
| kip->slot_used[idx] = SLOT_CLEAN; |
| kip->nused--; |
| if (kip->nused == 0) { |
| /* |
| * Page is no longer in use. Free it unless |
| * it's the last one. We keep the last one |
| * so as not to have to set it up again the |
| * next time somebody inserts a probe. |
| */ |
| if (!list_is_singular(&kip->list)) { |
| /* |
| * Record perf ksymbol unregister event before removing |
| * the page. |
| */ |
| perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, |
| (unsigned long)kip->insns, PAGE_SIZE, true, |
| kip->cache->sym); |
| list_del_rcu(&kip->list); |
| synchronize_rcu(); |
| kip->cache->free(kip->insns); |
| kfree(kip); |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| static int collect_garbage_slots(struct kprobe_insn_cache *c) |
| { |
| struct kprobe_insn_page *kip, *next; |
| |
| /* Ensure no-one is interrupted on the garbages */ |
| synchronize_rcu(); |
| |
| list_for_each_entry_safe(kip, next, &c->pages, list) { |
| int i; |
| |
| if (kip->ngarbage == 0) |
| continue; |
| kip->ngarbage = 0; /* we will collect all garbages */ |
| for (i = 0; i < slots_per_page(c); i++) { |
| if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
| break; |
| } |
| } |
| c->nr_garbage = 0; |
| return 0; |
| } |
| |
| void __free_insn_slot(struct kprobe_insn_cache *c, |
| kprobe_opcode_t *slot, int dirty) |
| { |
| struct kprobe_insn_page *kip; |
| long idx; |
| |
| mutex_lock(&c->mutex); |
| rcu_read_lock(); |
| list_for_each_entry_rcu(kip, &c->pages, list) { |
| idx = ((long)slot - (long)kip->insns) / |
| (c->insn_size * sizeof(kprobe_opcode_t)); |
| if (idx >= 0 && idx < slots_per_page(c)) |
| goto out; |
| } |
| /* Could not find this slot. */ |
| WARN_ON(1); |
| kip = NULL; |
| out: |
| rcu_read_unlock(); |
| /* Mark and sweep: this may sleep */ |
| if (kip) { |
| /* Check double free */ |
| WARN_ON(kip->slot_used[idx] != SLOT_USED); |
| if (dirty) { |
| kip->slot_used[idx] = SLOT_DIRTY; |
| kip->ngarbage++; |
| if (++c->nr_garbage > slots_per_page(c)) |
| collect_garbage_slots(c); |
| } else { |
| collect_one_slot(kip, idx); |
| } |
| } |
| mutex_unlock(&c->mutex); |
| } |
| |
| /* |
| * Check given address is on the page of kprobe instruction slots. |
| * This will be used for checking whether the address on a stack |
| * is on a text area or not. |
| */ |
| bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) |
| { |
| struct kprobe_insn_page *kip; |
| bool ret = false; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(kip, &c->pages, list) { |
| if (addr >= (unsigned long)kip->insns && |
| addr < (unsigned long)kip->insns + PAGE_SIZE) { |
| ret = true; |
| break; |
| } |
| } |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum, |
| unsigned long *value, char *type, char *sym) |
| { |
| struct kprobe_insn_page *kip; |
| int ret = -ERANGE; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(kip, &c->pages, list) { |
| if ((*symnum)--) |
| continue; |
| strscpy(sym, c->sym, KSYM_NAME_LEN); |
| *type = 't'; |
| *value = (unsigned long)kip->insns; |
| ret = 0; |
| break; |
| } |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_OPTPROBES |
| void __weak *alloc_optinsn_page(void) |
| { |
| return alloc_insn_page(); |
| } |
| |
| void __weak free_optinsn_page(void *page) |
| { |
| free_insn_page(page); |
| } |
| |
| /* For optimized_kprobe buffer */ |
| struct kprobe_insn_cache kprobe_optinsn_slots = { |
| .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), |
| .alloc = alloc_optinsn_page, |
| .free = free_optinsn_page, |
| .sym = KPROBE_OPTINSN_PAGE_SYM, |
| .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
| /* .insn_size is initialized later */ |
| .nr_garbage = 0, |
| }; |
| #endif |
| #endif |
| |
| /* We have preemption disabled.. so it is safe to use __ versions */ |
| static inline void set_kprobe_instance(struct kprobe *kp) |
| { |
| __this_cpu_write(kprobe_instance, kp); |
| } |
| |
| static inline void reset_kprobe_instance(void) |
| { |
| __this_cpu_write(kprobe_instance, NULL); |
| } |
| |
| /* |
| * This routine is called either: |
| * - under the 'kprobe_mutex' - during kprobe_[un]register(). |
| * OR |
| * - with preemption disabled - from architecture specific code. |
| */ |
| struct kprobe *get_kprobe(void *addr) |
| { |
| struct hlist_head *head; |
| struct kprobe *p; |
| |
| head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
| hlist_for_each_entry_rcu(p, head, hlist, |
| lockdep_is_held(&kprobe_mutex)) { |
| if (p->addr == addr) |
| return p; |
| } |
| |
| return NULL; |
| } |
| NOKPROBE_SYMBOL(get_kprobe); |
| |
| static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
| |
| /* Return true if 'p' is an aggregator */ |
| static inline bool kprobe_aggrprobe(struct kprobe *p) |
| { |
| return p->pre_handler == aggr_pre_handler; |
| } |
| |
| /* Return true if 'p' is unused */ |
| static inline bool kprobe_unused(struct kprobe *p) |
| { |
| return kprobe_aggrprobe(p) && kprobe_disabled(p) && |
| list_empty(&p->list); |
| } |
| |
| /* Keep all fields in the kprobe consistent. */ |
| static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
| memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); |
| } |
| |
| #ifdef CONFIG_OPTPROBES |
| /* NOTE: This is protected by 'kprobe_mutex'. */ |
| static bool kprobes_allow_optimization; |
| |
| /* |
| * Call all 'kprobe::pre_handler' on the list, but ignores its return value. |
| * This must be called from arch-dep optimized caller. |
| */ |
| void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| kp->pre_handler(kp, regs); |
| } |
| reset_kprobe_instance(); |
| } |
| } |
| NOKPROBE_SYMBOL(opt_pre_handler); |
| |
| /* Free optimized instructions and optimized_kprobe */ |
| static void free_aggr_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| arch_remove_optimized_kprobe(op); |
| arch_remove_kprobe(p); |
| kfree(op); |
| } |
| |
| /* Return true if the kprobe is ready for optimization. */ |
| static inline int kprobe_optready(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| if (kprobe_aggrprobe(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| return arch_prepared_optinsn(&op->optinsn); |
| } |
| |
| return 0; |
| } |
| |
| /* Return true if the kprobe is disarmed. Note: p must be on hash list */ |
| bool kprobe_disarmed(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ |
| if (!kprobe_aggrprobe(p)) |
| return kprobe_disabled(p); |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| |
| return kprobe_disabled(p) && list_empty(&op->list); |
| } |
| |
| /* Return true if the probe is queued on (un)optimizing lists */ |
| static bool kprobe_queued(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| if (kprobe_aggrprobe(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!list_empty(&op->list)) |
| return true; |
| } |
| return false; |
| } |
| |
| /* |
| * Return an optimized kprobe whose optimizing code replaces |
| * instructions including 'addr' (exclude breakpoint). |
| */ |
| static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr) |
| { |
| int i; |
| struct kprobe *p = NULL; |
| struct optimized_kprobe *op; |
| |
| /* Don't check i == 0, since that is a breakpoint case. */ |
| for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) |
| p = get_kprobe(addr - i); |
| |
| if (p && kprobe_optready(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (arch_within_optimized_kprobe(op, addr)) |
| return p; |
| } |
| |
| return NULL; |
| } |
| |
| /* Optimization staging list, protected by 'kprobe_mutex' */ |
| static LIST_HEAD(optimizing_list); |
| static LIST_HEAD(unoptimizing_list); |
| static LIST_HEAD(freeing_list); |
| |
| static void kprobe_optimizer(struct work_struct *work); |
| static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); |
| #define OPTIMIZE_DELAY 5 |
| |
| /* |
| * Optimize (replace a breakpoint with a jump) kprobes listed on |
| * 'optimizing_list'. |
| */ |
| static void do_optimize_kprobes(void) |
| { |
| lockdep_assert_held(&text_mutex); |
| /* |
| * The optimization/unoptimization refers 'online_cpus' via |
| * stop_machine() and cpu-hotplug modifies the 'online_cpus'. |
| * And same time, 'text_mutex' will be held in cpu-hotplug and here. |
| * This combination can cause a deadlock (cpu-hotplug tries to lock |
| * 'text_mutex' but stop_machine() can not be done because |
| * the 'online_cpus' has been changed) |
| * To avoid this deadlock, caller must have locked cpu-hotplug |
| * for preventing cpu-hotplug outside of 'text_mutex' locking. |
| */ |
| lockdep_assert_cpus_held(); |
| |
| /* Optimization never be done when disarmed */ |
| if (kprobes_all_disarmed || !kprobes_allow_optimization || |
| list_empty(&optimizing_list)) |
| return; |
| |
| arch_optimize_kprobes(&optimizing_list); |
| } |
| |
| /* |
| * Unoptimize (replace a jump with a breakpoint and remove the breakpoint |
| * if need) kprobes listed on 'unoptimizing_list'. |
| */ |
| static void do_unoptimize_kprobes(void) |
| { |
| struct optimized_kprobe *op, *tmp; |
| |
| lockdep_assert_held(&text_mutex); |
| /* See comment in do_optimize_kprobes() */ |
| lockdep_assert_cpus_held(); |
| |
| if (!list_empty(&unoptimizing_list)) |
| arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
| |
| /* Loop on 'freeing_list' for disarming and removing from kprobe hash list */ |
| list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
| /* Switching from detour code to origin */ |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| /* Disarm probes if marked disabled and not gone */ |
| if (kprobe_disabled(&op->kp) && !kprobe_gone(&op->kp)) |
| arch_disarm_kprobe(&op->kp); |
| if (kprobe_unused(&op->kp)) { |
| /* |
| * Remove unused probes from hash list. After waiting |
| * for synchronization, these probes are reclaimed. |
| * (reclaiming is done by do_free_cleaned_kprobes().) |
| */ |
| hlist_del_rcu(&op->kp.hlist); |
| } else |
| list_del_init(&op->list); |
| } |
| } |
| |
| /* Reclaim all kprobes on the 'freeing_list' */ |
| static void do_free_cleaned_kprobes(void) |
| { |
| struct optimized_kprobe *op, *tmp; |
| |
| list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
| list_del_init(&op->list); |
| if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) { |
| /* |
| * This must not happen, but if there is a kprobe |
| * still in use, keep it on kprobes hash list. |
| */ |
| continue; |
| } |
| free_aggr_kprobe(&op->kp); |
| } |
| } |
| |
| /* Start optimizer after OPTIMIZE_DELAY passed */ |
| static void kick_kprobe_optimizer(void) |
| { |
| schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
| } |
| |
| /* Kprobe jump optimizer */ |
| static void kprobe_optimizer(struct work_struct *work) |
| { |
| mutex_lock(&kprobe_mutex); |
| cpus_read_lock(); |
| mutex_lock(&text_mutex); |
| |
| /* |
| * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
| * kprobes before waiting for quiesence period. |
| */ |
| do_unoptimize_kprobes(); |
| |
| /* |
| * Step 2: Wait for quiesence period to ensure all potentially |
| * preempted tasks to have normally scheduled. Because optprobe |
| * may modify multiple instructions, there is a chance that Nth |
| * instruction is preempted. In that case, such tasks can return |
| * to 2nd-Nth byte of jump instruction. This wait is for avoiding it. |
| * Note that on non-preemptive kernel, this is transparently converted |
| * to synchronoze_sched() to wait for all interrupts to have completed. |
| */ |
| synchronize_rcu_tasks(); |
| |
| /* Step 3: Optimize kprobes after quiesence period */ |
| do_optimize_kprobes(); |
| |
| /* Step 4: Free cleaned kprobes after quiesence period */ |
| do_free_cleaned_kprobes(); |
| |
| mutex_unlock(&text_mutex); |
| cpus_read_unlock(); |
| |
| /* Step 5: Kick optimizer again if needed */ |
| if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
| kick_kprobe_optimizer(); |
| |
| mutex_unlock(&kprobe_mutex); |
| } |
| |
| /* Wait for completing optimization and unoptimization */ |
| void wait_for_kprobe_optimizer(void) |
| { |
| mutex_lock(&kprobe_mutex); |
| |
| while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { |
| mutex_unlock(&kprobe_mutex); |
| |
| /* This will also make 'optimizing_work' execute immmediately */ |
| flush_delayed_work(&optimizing_work); |
| /* 'optimizing_work' might not have been queued yet, relax */ |
| cpu_relax(); |
| |
| mutex_lock(&kprobe_mutex); |
| } |
| |
| mutex_unlock(&kprobe_mutex); |
| } |
| |
| bool optprobe_queued_unopt(struct optimized_kprobe *op) |
| { |
| struct optimized_kprobe *_op; |
| |
| list_for_each_entry(_op, &unoptimizing_list, list) { |
| if (op == _op) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Optimize kprobe if p is ready to be optimized */ |
| static void optimize_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| /* Check if the kprobe is disabled or not ready for optimization. */ |
| if (!kprobe_optready(p) || !kprobes_allow_optimization || |
| (kprobe_disabled(p) || kprobes_all_disarmed)) |
| return; |
| |
| /* kprobes with 'post_handler' can not be optimized */ |
| if (p->post_handler) |
| return; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| |
| /* Check there is no other kprobes at the optimized instructions */ |
| if (arch_check_optimized_kprobe(op) < 0) |
| return; |
| |
| /* Check if it is already optimized. */ |
| if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) { |
| if (optprobe_queued_unopt(op)) { |
| /* This is under unoptimizing. Just dequeue the probe */ |
| list_del_init(&op->list); |
| } |
| return; |
| } |
| op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
| |
| /* |
| * On the 'unoptimizing_list' and 'optimizing_list', |
| * 'op' must have OPTIMIZED flag |
| */ |
| if (WARN_ON_ONCE(!list_empty(&op->list))) |
| return; |
| |
| list_add(&op->list, &optimizing_list); |
| kick_kprobe_optimizer(); |
| } |
| |
| /* Short cut to direct unoptimizing */ |
| static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
| { |
| lockdep_assert_cpus_held(); |
| arch_unoptimize_kprobe(op); |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| } |
| |
| /* Unoptimize a kprobe if p is optimized */ |
| static void unoptimize_kprobe(struct kprobe *p, bool force) |
| { |
| struct optimized_kprobe *op; |
| |
| if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
| return; /* This is not an optprobe nor optimized */ |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!kprobe_optimized(p)) |
| return; |
| |
| if (!list_empty(&op->list)) { |
| if (optprobe_queued_unopt(op)) { |
| /* Queued in unoptimizing queue */ |
| if (force) { |
| /* |
| * Forcibly unoptimize the kprobe here, and queue it |
| * in the freeing list for release afterwards. |
| */ |
| force_unoptimize_kprobe(op); |
| list_move(&op->list, &freeing_list); |
| } |
| } else { |
| /* Dequeue from the optimizing queue */ |
| list_del_init(&op->list); |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| } |
| return; |
| } |
| |
| /* Optimized kprobe case */ |
| if (force) { |
| /* Forcibly update the code: this is a special case */ |
| force_unoptimize_kprobe(op); |
| } else { |
| list_add(&op->list, &unoptimizing_list); |
| kick_kprobe_optimizer(); |
| } |
| } |
| |
| /* Cancel unoptimizing for reusing */ |
| static int reuse_unused_kprobe(struct kprobe *ap) |
| { |
| struct optimized_kprobe *op; |
| |
| /* |
| * Unused kprobe MUST be on the way of delayed unoptimizing (means |
| * there is still a relative jump) and disabled. |
| */ |
| op = container_of(ap, struct optimized_kprobe, kp); |
| WARN_ON_ONCE(list_empty(&op->list)); |
| /* Enable the probe again */ |
| ap->flags &= ~KPROBE_FLAG_DISABLED; |
| /* Optimize it again. (remove from 'op->list') */ |
| if (!kprobe_optready(ap)) |
| return -EINVAL; |
| |
| optimize_kprobe(ap); |
| return 0; |
| } |
| |
| /* Remove optimized instructions */ |
| static void kill_optimized_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!list_empty(&op->list)) |
| /* Dequeue from the (un)optimization queue */ |
| list_del_init(&op->list); |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| |
| if (kprobe_unused(p)) { |
| /* |
| * Unused kprobe is on unoptimizing or freeing list. We move it |
| * to freeing_list and let the kprobe_optimizer() remove it from |
| * the kprobe hash list and free it. |
| */ |
| if (optprobe_queued_unopt(op)) |
| list_move(&op->list, &freeing_list); |
| } |
| |
| /* Don't touch the code, because it is already freed. */ |
| arch_remove_optimized_kprobe(op); |
| } |
| |
| static inline |
| void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) |
| { |
| if (!kprobe_ftrace(p)) |
| arch_prepare_optimized_kprobe(op, p); |
| } |
| |
| /* Try to prepare optimized instructions */ |
| static void prepare_optimized_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| __prepare_optimized_kprobe(op, p); |
| } |
| |
| /* Allocate new optimized_kprobe and try to prepare optimized instructions. */ |
| static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); |
| if (!op) |
| return NULL; |
| |
| INIT_LIST_HEAD(&op->list); |
| op->kp.addr = p->addr; |
| __prepare_optimized_kprobe(op, p); |
| |
| return &op->kp; |
| } |
| |
| static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
| |
| /* |
| * Prepare an optimized_kprobe and optimize it. |
| * NOTE: 'p' must be a normal registered kprobe. |
| */ |
| static void try_to_optimize_kprobe(struct kprobe *p) |
| { |
| struct kprobe *ap; |
| struct optimized_kprobe *op; |
| |
| /* Impossible to optimize ftrace-based kprobe. */ |
| if (kprobe_ftrace(p)) |
| return; |
| |
| /* For preparing optimization, jump_label_text_reserved() is called. */ |
| cpus_read_lock(); |
| jump_label_lock(); |
| mutex_lock(&text_mutex); |
| |
| ap = alloc_aggr_kprobe(p); |
| if (!ap) |
| goto out; |
| |
| op = container_of(ap, struct optimized_kprobe, kp); |
| if (!arch_prepared_optinsn(&op->optinsn)) { |
| /* If failed to setup optimizing, fallback to kprobe. */ |
| arch_remove_optimized_kprobe(op); |
| kfree(op); |
| goto out; |
| } |
| |
| init_aggr_kprobe(ap, p); |
| optimize_kprobe(ap); /* This just kicks optimizer thread. */ |
| |
| out: |
| mutex_unlock(&text_mutex); |
| jump_label_unlock(); |
| cpus_read_unlock(); |
| } |
| |
| static void optimize_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct kprobe *p; |
| unsigned int i; |
| |
| mutex_lock(&kprobe_mutex); |
| /* If optimization is already allowed, just return. */ |
| if (kprobes_allow_optimization) |
| goto out; |
| |
| cpus_read_lock(); |
| kprobes_allow_optimization = true; |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry(p, head, hlist) |
| if (!kprobe_disabled(p)) |
| optimize_kprobe(p); |
| } |
| cpus_read_unlock(); |
| pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n"); |
| out: |
| mutex_unlock(&kprobe_mutex); |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| static void unoptimize_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct kprobe *p; |
| unsigned int i; |
| |
| mutex_lock(&kprobe_mutex); |
| /* If optimization is already prohibited, just return. */ |
| if (!kprobes_allow_optimization) { |
| mutex_unlock(&kprobe_mutex); |
| return; |
| } |
| |
| cpus_read_lock(); |
| kprobes_allow_optimization = false; |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry(p, head, hlist) { |
| if (!kprobe_disabled(p)) |
| unoptimize_kprobe(p, false); |
| } |
| } |
| cpus_read_unlock(); |
| mutex_unlock(&kprobe_mutex); |
| |
| /* Wait for unoptimizing completion. */ |
| wait_for_kprobe_optimizer(); |
| pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n"); |
| } |
| |
| static DEFINE_MUTEX(kprobe_sysctl_mutex); |
| static int sysctl_kprobes_optimization; |
| static int proc_kprobes_optimization_handler(const struct ctl_table *table, |
| int write, void *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| int ret; |
| |
| mutex_lock(&kprobe_sysctl_mutex); |
| sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
| ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
| |
| if (sysctl_kprobes_optimization) |
| optimize_all_kprobes(); |
| else |
| unoptimize_all_kprobes(); |
| mutex_unlock(&kprobe_sysctl_mutex); |
| |
| return ret; |
| } |
| |
| static struct ctl_table kprobe_sysctls[] = { |
| { |
| .procname = "kprobes-optimization", |
| .data = &sysctl_kprobes_optimization, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_kprobes_optimization_handler, |
| .extra1 = SYSCTL_ZERO, |
| .extra2 = SYSCTL_ONE, |
| }, |
| }; |
| |
| static void __init kprobe_sysctls_init(void) |
| { |
| register_sysctl_init("debug", kprobe_sysctls); |
| } |
| #endif /* CONFIG_SYSCTL */ |
| |
| /* Put a breakpoint for a probe. */ |
| static void __arm_kprobe(struct kprobe *p) |
| { |
| struct kprobe *_p; |
| |
| lockdep_assert_held(&text_mutex); |
| |
| /* Find the overlapping optimized kprobes. */ |
| _p = get_optimized_kprobe(p->addr); |
| if (unlikely(_p)) |
| /* Fallback to unoptimized kprobe */ |
| unoptimize_kprobe(_p, true); |
| |
| arch_arm_kprobe(p); |
| optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ |
| } |
| |
| /* Remove the breakpoint of a probe. */ |
| static void __disarm_kprobe(struct kprobe *p, bool reopt) |
| { |
| struct kprobe *_p; |
| |
| lockdep_assert_held(&text_mutex); |
| |
| /* Try to unoptimize */ |
| unoptimize_kprobe(p, kprobes_all_disarmed); |
| |
| if (!kprobe_queued(p)) { |
| arch_disarm_kprobe(p); |
| /* If another kprobe was blocked, re-optimize it. */ |
| _p = get_optimized_kprobe(p->addr); |
| if (unlikely(_p) && reopt) |
| optimize_kprobe(_p); |
| } |
| /* |
| * TODO: Since unoptimization and real disarming will be done by |
| * the worker thread, we can not check whether another probe are |
| * unoptimized because of this probe here. It should be re-optimized |
| * by the worker thread. |
| */ |
| } |
| |
| #else /* !CONFIG_OPTPROBES */ |
| |
| #define optimize_kprobe(p) do {} while (0) |
| #define unoptimize_kprobe(p, f) do {} while (0) |
| #define kill_optimized_kprobe(p) do {} while (0) |
| #define prepare_optimized_kprobe(p) do {} while (0) |
| #define try_to_optimize_kprobe(p) do {} while (0) |
| #define __arm_kprobe(p) arch_arm_kprobe(p) |
| #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
| #define kprobe_disarmed(p) kprobe_disabled(p) |
| #define wait_for_kprobe_optimizer() do {} while (0) |
| |
| static int reuse_unused_kprobe(struct kprobe *ap) |
| { |
| /* |
| * If the optimized kprobe is NOT supported, the aggr kprobe is |
| * released at the same time that the last aggregated kprobe is |
| * unregistered. |
| * Thus there should be no chance to reuse unused kprobe. |
| */ |
| WARN_ON_ONCE(1); |
| return -EINVAL; |
| } |
| |
| static void free_aggr_kprobe(struct kprobe *p) |
| { |
| arch_remove_kprobe(p); |
| kfree(p); |
| } |
| |
| static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
| { |
| return kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
| } |
| #endif /* CONFIG_OPTPROBES */ |
| |
| #ifdef CONFIG_KPROBES_ON_FTRACE |
| static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
| .func = kprobe_ftrace_handler, |
| .flags = FTRACE_OPS_FL_SAVE_REGS, |
| }; |
| |
| static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { |
| .func = kprobe_ftrace_handler, |
| .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
| }; |
| |
| static int kprobe_ipmodify_enabled; |
| static int kprobe_ftrace_enabled; |
| bool kprobe_ftrace_disabled; |
| |
| static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
| int *cnt) |
| { |
| int ret; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); |
| if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret)) |
| return ret; |
| |
| if (*cnt == 0) { |
| ret = register_ftrace_function(ops); |
| if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret)) |
| goto err_ftrace; |
| } |
| |
| (*cnt)++; |
| return ret; |
| |
| err_ftrace: |
| /* |
| * At this point, sinec ops is not registered, we should be sefe from |
| * registering empty filter. |
| */ |
| ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
| return ret; |
| } |
| |
| static int arm_kprobe_ftrace(struct kprobe *p) |
| { |
| bool ipmodify = (p->post_handler != NULL); |
| |
| return __arm_kprobe_ftrace(p, |
| ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, |
| ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); |
| } |
| |
| static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
| int *cnt) |
| { |
| int ret; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| if (*cnt == 1) { |
| ret = unregister_ftrace_function(ops); |
| if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret)) |
| return ret; |
| } |
| |
| (*cnt)--; |
| |
| ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
| WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n", |
| p->addr, ret); |
| return ret; |
| } |
| |
| static int disarm_kprobe_ftrace(struct kprobe *p) |
| { |
| bool ipmodify = (p->post_handler != NULL); |
| |
| return __disarm_kprobe_ftrace(p, |
| ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, |
| ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); |
| } |
| |
| void kprobe_ftrace_kill(void) |
| { |
| kprobe_ftrace_disabled = true; |
| } |
| #else /* !CONFIG_KPROBES_ON_FTRACE */ |
| static inline int arm_kprobe_ftrace(struct kprobe *p) |
| { |
| return -ENODEV; |
| } |
| |
| static inline int disarm_kprobe_ftrace(struct kprobe *p) |
| { |
| return -ENODEV; |
| } |
| #endif |
| |
| static int prepare_kprobe(struct kprobe *p) |
| { |
| /* Must ensure p->addr is really on ftrace */ |
| if (kprobe_ftrace(p)) |
| return arch_prepare_kprobe_ftrace(p); |
| |
| return arch_prepare_kprobe(p); |
| } |
| |
| static int arm_kprobe(struct kprobe *kp) |
| { |
| if (unlikely(kprobe_ftrace(kp))) |
| return arm_kprobe_ftrace(kp); |
| |
| cpus_read_lock(); |
| mutex_lock(&text_mutex); |
| __arm_kprobe(kp); |
| mutex_unlock(&text_mutex); |
| cpus_read_unlock(); |
| |
| return 0; |
| } |
| |
| static int disarm_kprobe(struct kprobe *kp, bool reopt) |
| { |
| if (unlikely(kprobe_ftrace(kp))) |
| return disarm_kprobe_ftrace(kp); |
| |
| cpus_read_lock(); |
| mutex_lock(&text_mutex); |
| __disarm_kprobe(kp, reopt); |
| mutex_unlock(&text_mutex); |
| cpus_read_unlock(); |
| |
| return 0; |
| } |
| |
| /* |
| * Aggregate handlers for multiple kprobes support - these handlers |
| * take care of invoking the individual kprobe handlers on p->list |
| */ |
| static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| if (kp->pre_handler(kp, regs)) |
| return 1; |
| } |
| reset_kprobe_instance(); |
| } |
| return 0; |
| } |
| NOKPROBE_SYMBOL(aggr_pre_handler); |
| |
| static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
| unsigned long flags) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| kp->post_handler(kp, regs, flags); |
| reset_kprobe_instance(); |
| } |
| } |
| } |
| NOKPROBE_SYMBOL(aggr_post_handler); |
| |
| /* Walks the list and increments 'nmissed' if 'p' has child probes. */ |
| void kprobes_inc_nmissed_count(struct kprobe *p) |
| { |
| struct kprobe *kp; |
| |
| if (!kprobe_aggrprobe(p)) { |
| p->nmissed++; |
| } else { |
| list_for_each_entry_rcu(kp, &p->list, list) |
| kp->nmissed++; |
| } |
| } |
| NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
| |
| static struct kprobe kprobe_busy = { |
| .addr = (void *) get_kprobe, |
| }; |
| |
| void kprobe_busy_begin(void) |
| { |
| struct kprobe_ctlblk *kcb; |
| |
| preempt_disable(); |
| __this_cpu_write(current_kprobe, &kprobe_busy); |
| kcb = get_kprobe_ctlblk(); |
| kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
| } |
| |
| void kprobe_busy_end(void) |
| { |
| __this_cpu_write(current_kprobe, NULL); |
| preempt_enable(); |
| } |
| |
| /* Add the new probe to 'ap->list'. */ |
| static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| if (p->post_handler) |
| unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
| |
| list_add_rcu(&p->list, &ap->list); |
| if (p->post_handler && !ap->post_handler) |
| ap->post_handler = aggr_post_handler; |
| |
| return 0; |
| } |
| |
| /* |
| * Fill in the required fields of the aggregator kprobe. Replace the |
| * earlier kprobe in the hlist with the aggregator kprobe. |
| */ |
| static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| /* Copy the insn slot of 'p' to 'ap'. */ |
| copy_kprobe(p, ap); |
| flush_insn_slot(ap); |
| ap->addr = p->addr; |
| ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
| ap->pre_handler = aggr_pre_handler; |
| /* We don't care the kprobe which has gone. */ |
| if (p->post_handler && !kprobe_gone(p)) |
| ap->post_handler = aggr_post_handler; |
| |
| INIT_LIST_HEAD(&ap->list); |
| INIT_HLIST_NODE(&ap->hlist); |
| |
| list_add_rcu(&p->list, &ap->list); |
| hlist_replace_rcu(&p->hlist, &ap->hlist); |
| } |
| |
| /* |
| * This registers the second or subsequent kprobe at the same address. |
| */ |
| static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
| { |
| int ret = 0; |
| struct kprobe *ap = orig_p; |
| |
| cpus_read_lock(); |
| |
| /* For preparing optimization, jump_label_text_reserved() is called */ |
| jump_label_lock(); |
| mutex_lock(&text_mutex); |
| |
| if (!kprobe_aggrprobe(orig_p)) { |
| /* If 'orig_p' is not an 'aggr_kprobe', create new one. */ |
| ap = alloc_aggr_kprobe(orig_p); |
| if (!ap) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| init_aggr_kprobe(ap, orig_p); |
| } else if (kprobe_unused(ap)) { |
| /* This probe is going to die. Rescue it */ |
| ret = reuse_unused_kprobe(ap); |
| if (ret) |
| goto out; |
| } |
| |
| if (kprobe_gone(ap)) { |
| /* |
| * Attempting to insert new probe at the same location that |
| * had a probe in the module vaddr area which already |
| * freed. So, the instruction slot has already been |
| * released. We need a new slot for the new probe. |
| */ |
| ret = arch_prepare_kprobe(ap); |
| if (ret) |
| /* |
| * Even if fail to allocate new slot, don't need to |
| * free the 'ap'. It will be used next time, or |
| * freed by unregister_kprobe(). |
| */ |
| goto out; |
| |
| /* Prepare optimized instructions if possible. */ |
| prepare_optimized_kprobe(ap); |
| |
| /* |
| * Clear gone flag to prevent allocating new slot again, and |
| * set disabled flag because it is not armed yet. |
| */ |
| ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
| | KPROBE_FLAG_DISABLED; |
| } |
| |
| /* Copy the insn slot of 'p' to 'ap'. */ |
| copy_kprobe(ap, p); |
| ret = add_new_kprobe(ap, p); |
| |
| out: |
| mutex_unlock(&text_mutex); |
| jump_label_unlock(); |
| cpus_read_unlock(); |
| |
| if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { |
| ap->flags &= ~KPROBE_FLAG_DISABLED; |
| if (!kprobes_all_disarmed) { |
| /* Arm the breakpoint again. */ |
| ret = arm_kprobe(ap); |
| if (ret) { |
| ap->flags |= KPROBE_FLAG_DISABLED; |
| list_del_rcu(&p->list); |
| synchronize_rcu(); |
| } |
| } |
| } |
| return ret; |
| } |
| |
| bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
| { |
| /* The '__kprobes' functions and entry code must not be probed. */ |
| return addr >= (unsigned long)__kprobes_text_start && |
| addr < (unsigned long)__kprobes_text_end; |
| } |
| |
| static bool __within_kprobe_blacklist(unsigned long addr) |
| { |
| struct kprobe_blacklist_entry *ent; |
| |
| if (arch_within_kprobe_blacklist(addr)) |
| return true; |
| /* |
| * If 'kprobe_blacklist' is defined, check the address and |
| * reject any probe registration in the prohibited area. |
| */ |
| list_for_each_entry(ent, &kprobe_blacklist, list) { |
| if (addr >= ent->start_addr && addr < ent->end_addr) |
| return true; |
| } |
| return false; |
| } |
| |
| bool within_kprobe_blacklist(unsigned long addr) |
| { |
| char symname[KSYM_NAME_LEN], *p; |
| |
| if (__within_kprobe_blacklist(addr)) |
| return true; |
| |
| /* Check if the address is on a suffixed-symbol */ |
| if (!lookup_symbol_name(addr, symname)) { |
| p = strchr(symname, '.'); |
| if (!p) |
| return false; |
| *p = '\0'; |
| addr = (unsigned long)kprobe_lookup_name(symname, 0); |
| if (addr) |
| return __within_kprobe_blacklist(addr); |
| } |
| return false; |
| } |
| |
| /* |
| * arch_adjust_kprobe_addr - adjust the address |
| * @addr: symbol base address |
| * @offset: offset within the symbol |
| * @on_func_entry: was this @addr+@offset on the function entry |
| * |
| * Typically returns @addr + @offset, except for special cases where the |
| * function might be prefixed by a CFI landing pad, in that case any offset |
| * inside the landing pad is mapped to the first 'real' instruction of the |
| * symbol. |
| * |
| * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C |
| * instruction at +0. |
| */ |
| kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr, |
| unsigned long offset, |
| bool *on_func_entry) |
| { |
| *on_func_entry = !offset; |
| return (kprobe_opcode_t *)(addr + offset); |
| } |
| |
| /* |
| * If 'symbol_name' is specified, look it up and add the 'offset' |
| * to it. This way, we can specify a relative address to a symbol. |
| * This returns encoded errors if it fails to look up symbol or invalid |
| * combination of parameters. |
| */ |
| static kprobe_opcode_t * |
| _kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name, |
| unsigned long offset, bool *on_func_entry) |
| { |
| if ((symbol_name && addr) || (!symbol_name && !addr)) |
| goto invalid; |
| |
| if (symbol_name) { |
| /* |
| * Input: @sym + @offset |
| * Output: @addr + @offset |
| * |
| * NOTE: kprobe_lookup_name() does *NOT* fold the offset |
| * argument into it's output! |
| */ |
| addr = kprobe_lookup_name(symbol_name, offset); |
| if (!addr) |
| return ERR_PTR(-ENOENT); |
| } |
| |
| /* |
| * So here we have @addr + @offset, displace it into a new |
| * @addr' + @offset' where @addr' is the symbol start address. |
| */ |
| addr = (void *)addr + offset; |
| if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset)) |
| return ERR_PTR(-ENOENT); |
| addr = (void *)addr - offset; |
| |
| /* |
| * Then ask the architecture to re-combine them, taking care of |
| * magical function entry details while telling us if this was indeed |
| * at the start of the function. |
| */ |
| addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry); |
| if (addr) |
| return addr; |
| |
| invalid: |
| return ERR_PTR(-EINVAL); |
| } |
| |
| static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
| { |
| bool on_func_entry; |
| return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry); |
| } |
| |
| /* |
| * Check the 'p' is valid and return the aggregator kprobe |
| * at the same address. |
| */ |
| static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
| { |
| struct kprobe *ap, *list_p; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| ap = get_kprobe(p->addr); |
| if (unlikely(!ap)) |
| return NULL; |
| |
| if (p != ap) { |
| list_for_each_entry(list_p, &ap->list, list) |
| if (list_p == p) |
| /* kprobe p is a valid probe */ |
| goto valid; |
| return NULL; |
| } |
| valid: |
| return ap; |
| } |
| |
| /* |
| * Warn and return error if the kprobe is being re-registered since |
| * there must be a software bug. |
| */ |
| static inline int warn_kprobe_rereg(struct kprobe *p) |
| { |
| int ret = 0; |
| |
| mutex_lock(&kprobe_mutex); |
| if (WARN_ON_ONCE(__get_valid_kprobe(p))) |
| ret = -EINVAL; |
| mutex_unlock(&kprobe_mutex); |
| |
| return ret; |
| } |
| |
| static int check_ftrace_location(struct kprobe *p) |
| { |
| unsigned long addr = (unsigned long)p->addr; |
| |
| if (ftrace_location(addr) == addr) { |
| #ifdef CONFIG_KPROBES_ON_FTRACE |
| p->flags |= KPROBE_FLAG_FTRACE; |
| #else /* !CONFIG_KPROBES_ON_FTRACE */ |
| return -EINVAL; |
| #endif |
| } |
| return 0; |
| } |
| |
| static bool is_cfi_preamble_symbol(unsigned long addr) |
| { |
| char symbuf[KSYM_NAME_LEN]; |
| |
| if (lookup_symbol_name(addr, symbuf)) |
| return false; |
| |
| return str_has_prefix("__cfi_", symbuf) || |
| str_has_prefix("__pfx_", symbuf); |
| } |
| |
| static int check_kprobe_address_safe(struct kprobe *p, |
| struct module **probed_mod) |
| { |
| int ret; |
| |
| ret = check_ftrace_location(p); |
| if (ret) |
| return ret; |
| jump_label_lock(); |
| preempt_disable(); |
| |
| /* Ensure the address is in a text area, and find a module if exists. */ |
| *probed_mod = NULL; |
| if (!core_kernel_text((unsigned long) p->addr)) { |
| *probed_mod = __module_text_address((unsigned long) p->addr); |
| if (!(*probed_mod)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| } |
| /* Ensure it is not in reserved area. */ |
| if (in_gate_area_no_mm((unsigned long) p->addr) || |
| within_kprobe_blacklist((unsigned long) p->addr) || |
| jump_label_text_reserved(p->addr, p->addr) || |
| static_call_text_reserved(p->addr, p->addr) || |
| find_bug((unsigned long)p->addr) || |
| is_cfi_preamble_symbol((unsigned long)p->addr)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* Get module refcount and reject __init functions for loaded modules. */ |
| if (IS_ENABLED(CONFIG_MODULES) && *probed_mod) { |
| /* |
| * We must hold a refcount of the probed module while updating |
| * its code to prohibit unexpected unloading. |
| */ |
| if (unlikely(!try_module_get(*probed_mod))) { |
| ret = -ENOENT; |
| goto out; |
| } |
| |
| /* |
| * If the module freed '.init.text', we couldn't insert |
| * kprobes in there. |
| */ |
| if (within_module_init((unsigned long)p->addr, *probed_mod) && |
| !module_is_coming(*probed_mod)) { |
| module_put(*probed_mod); |
| *probed_mod = NULL; |
| ret = -ENOENT; |
| } |
| } |
| |
| out: |
| preempt_enable(); |
| jump_label_unlock(); |
| |
| return ret; |
| } |
| |
| int register_kprobe(struct kprobe *p) |
| { |
| int ret; |
| struct kprobe *old_p; |
| struct module *probed_mod; |
| kprobe_opcode_t *addr; |
| bool on_func_entry; |
| |
| /* Adjust probe address from symbol */ |
| addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry); |
| if (IS_ERR(addr)) |
| return PTR_ERR(addr); |
| p->addr = addr; |
| |
| ret = warn_kprobe_rereg(p); |
| if (ret) |
| return ret; |
| |
| /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
| p->flags &= KPROBE_FLAG_DISABLED; |
| p->nmissed = 0; |
| INIT_LIST_HEAD(&p->list); |
| |
| ret = check_kprobe_address_safe(p, &probed_mod); |
| if (ret) |
| return ret; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| if (on_func_entry) |
| p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY; |
| |
| old_p = get_kprobe(p->addr); |
| if (old_p) { |
| /* Since this may unoptimize 'old_p', locking 'text_mutex'. */ |
| ret = register_aggr_kprobe(old_p, p); |
| goto out; |
| } |
| |
| cpus_read_lock(); |
| /* Prevent text modification */ |
| mutex_lock(&text_mutex); |
| ret = prepare_kprobe(p); |
| mutex_unlock(&text_mutex); |
| cpus_read_unlock(); |
| if (ret) |
| goto out; |
| |
| INIT_HLIST_NODE(&p->hlist); |
| hlist_add_head_rcu(&p->hlist, |
| &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
| |
| if (!kprobes_all_disarmed && !kprobe_disabled(p)) { |
| ret = arm_kprobe(p); |
| if (ret) { |
| hlist_del_rcu(&p->hlist); |
| synchronize_rcu(); |
| goto out; |
| } |
| } |
| |
| /* Try to optimize kprobe */ |
| try_to_optimize_kprobe(p); |
| out: |
| mutex_unlock(&kprobe_mutex); |
| |
| if (probed_mod) |
| module_put(probed_mod); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kprobe); |
| |
| /* Check if all probes on the 'ap' are disabled. */ |
| static bool aggr_kprobe_disabled(struct kprobe *ap) |
| { |
| struct kprobe *kp; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| list_for_each_entry(kp, &ap->list, list) |
| if (!kprobe_disabled(kp)) |
| /* |
| * Since there is an active probe on the list, |
| * we can't disable this 'ap'. |
| */ |
| return false; |
| |
| return true; |
| } |
| |
| static struct kprobe *__disable_kprobe(struct kprobe *p) |
| { |
| struct kprobe *orig_p; |
| int ret; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| /* Get an original kprobe for return */ |
| orig_p = __get_valid_kprobe(p); |
| if (unlikely(orig_p == NULL)) |
| return ERR_PTR(-EINVAL); |
| |
| if (!kprobe_disabled(p)) { |
| /* Disable probe if it is a child probe */ |
| if (p != orig_p) |
| p->flags |= KPROBE_FLAG_DISABLED; |
| |
| /* Try to disarm and disable this/parent probe */ |
| if (p == orig_p || aggr_kprobe_disabled(orig_p)) { |
| /* |
| * Don't be lazy here. Even if 'kprobes_all_disarmed' |
| * is false, 'orig_p' might not have been armed yet. |
| * Note arm_all_kprobes() __tries__ to arm all kprobes |
| * on the best effort basis. |
| */ |
| if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) { |
| ret = disarm_kprobe(orig_p, true); |
| if (ret) { |
| p->flags &= ~KPROBE_FLAG_DISABLED; |
| return ERR_PTR(ret); |
| } |
| } |
| orig_p->flags |= KPROBE_FLAG_DISABLED; |
| } |
| } |
| |
| return orig_p; |
| } |
| |
| /* |
| * Unregister a kprobe without a scheduler synchronization. |
| */ |
| static int __unregister_kprobe_top(struct kprobe *p) |
| { |
| struct kprobe *ap, *list_p; |
| |
| /* Disable kprobe. This will disarm it if needed. */ |
| ap = __disable_kprobe(p); |
| if (IS_ERR(ap)) |
| return PTR_ERR(ap); |
| |
| if (ap == p) |
| /* |
| * This probe is an independent(and non-optimized) kprobe |
| * (not an aggrprobe). Remove from the hash list. |
| */ |
| goto disarmed; |
| |
| /* Following process expects this probe is an aggrprobe */ |
| WARN_ON(!kprobe_aggrprobe(ap)); |
| |
| if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
| /* |
| * !disarmed could be happen if the probe is under delayed |
| * unoptimizing. |
| */ |
| goto disarmed; |
| else { |
| /* If disabling probe has special handlers, update aggrprobe */ |
| if (p->post_handler && !kprobe_gone(p)) { |
| list_for_each_entry(list_p, &ap->list, list) { |
| if ((list_p != p) && (list_p->post_handler)) |
| goto noclean; |
| } |
| /* |
| * For the kprobe-on-ftrace case, we keep the |
| * post_handler setting to identify this aggrprobe |
| * armed with kprobe_ipmodify_ops. |
| */ |
| if (!kprobe_ftrace(ap)) |
| ap->post_handler = NULL; |
| } |
| noclean: |
| /* |
| * Remove from the aggrprobe: this path will do nothing in |
| * __unregister_kprobe_bottom(). |
| */ |
| list_del_rcu(&p->list); |
| if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
| /* |
| * Try to optimize this probe again, because post |
| * handler may have been changed. |
| */ |
| optimize_kprobe(ap); |
| } |
| return 0; |
| |
| disarmed: |
| hlist_del_rcu(&ap->hlist); |
| return 0; |
| } |
| |
| static void __unregister_kprobe_bottom(struct kprobe *p) |
| { |
| struct kprobe *ap; |
| |
| if (list_empty(&p->list)) |
| /* This is an independent kprobe */ |
| arch_remove_kprobe(p); |
| else if (list_is_singular(&p->list)) { |
| /* This is the last child of an aggrprobe */ |
| ap = list_entry(p->list.next, struct kprobe, list); |
| list_del(&p->list); |
| free_aggr_kprobe(ap); |
| } |
| /* Otherwise, do nothing. */ |
| } |
| |
| int register_kprobes(struct kprobe **kps, int num) |
| { |
| int i, ret = 0; |
| |
| if (num <= 0) |
| return -EINVAL; |
| for (i = 0; i < num; i++) { |
| ret = register_kprobe(kps[i]); |
| if (ret < 0) { |
| if (i > 0) |
| unregister_kprobes(kps, i); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kprobes); |
| |
| void unregister_kprobe(struct kprobe *p) |
| { |
| unregister_kprobes(&p, 1); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kprobe); |
| |
| void unregister_kprobes(struct kprobe **kps, int num) |
| { |
| int i; |
| |
| if (num <= 0) |
| return; |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < num; i++) |
| if (__unregister_kprobe_top(kps[i]) < 0) |
| kps[i]->addr = NULL; |
| mutex_unlock(&kprobe_mutex); |
| |
| synchronize_rcu(); |
| for (i = 0; i < num; i++) |
| if (kps[i]->addr) |
| __unregister_kprobe_bottom(kps[i]); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kprobes); |
| |
| int __weak kprobe_exceptions_notify(struct notifier_block *self, |
| unsigned long val, void *data) |
| { |
| return NOTIFY_DONE; |
| } |
| NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
| |
| static struct notifier_block kprobe_exceptions_nb = { |
| .notifier_call = kprobe_exceptions_notify, |
| .priority = 0x7fffffff /* we need to be notified first */ |
| }; |
| |
| #ifdef CONFIG_KRETPROBES |
| |
| #if !defined(CONFIG_KRETPROBE_ON_RETHOOK) |
| |
| /* callbacks for objpool of kretprobe instances */ |
| static int kretprobe_init_inst(void *nod, void *context) |
| { |
| struct kretprobe_instance *ri = nod; |
| |
| ri->rph = context; |
| return 0; |
| } |
| static int kretprobe_fini_pool(struct objpool_head *head, void *context) |
| { |
| kfree(context); |
| return 0; |
| } |
| |
| static void free_rp_inst_rcu(struct rcu_head *head) |
| { |
| struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu); |
| struct kretprobe_holder *rph = ri->rph; |
| |
| objpool_drop(ri, &rph->pool); |
| } |
| NOKPROBE_SYMBOL(free_rp_inst_rcu); |
| |
| static void recycle_rp_inst(struct kretprobe_instance *ri) |
| { |
| struct kretprobe *rp = get_kretprobe(ri); |
| |
| if (likely(rp)) |
| objpool_push(ri, &rp->rph->pool); |
| else |
| call_rcu(&ri->rcu, free_rp_inst_rcu); |
| } |
| NOKPROBE_SYMBOL(recycle_rp_inst); |
| |
| /* |
| * This function is called from delayed_put_task_struct() when a task is |
| * dead and cleaned up to recycle any kretprobe instances associated with |
| * this task. These left over instances represent probed functions that |
| * have been called but will never return. |
| */ |
| void kprobe_flush_task(struct task_struct *tk) |
| { |
| struct kretprobe_instance *ri; |
| struct llist_node *node; |
| |
| /* Early boot, not yet initialized. */ |
| if (unlikely(!kprobes_initialized)) |
| return; |
| |
| kprobe_busy_begin(); |
| |
| node = __llist_del_all(&tk->kretprobe_instances); |
| while (node) { |
| ri = container_of(node, struct kretprobe_instance, llist); |
| node = node->next; |
| |
| recycle_rp_inst(ri); |
| } |
| |
| kprobe_busy_end(); |
| } |
| NOKPROBE_SYMBOL(kprobe_flush_task); |
| |
| static inline void free_rp_inst(struct kretprobe *rp) |
| { |
| struct kretprobe_holder *rph = rp->rph; |
| |
| if (!rph) |
| return; |
| rp->rph = NULL; |
| objpool_fini(&rph->pool); |
| } |
| |
| /* This assumes the 'tsk' is the current task or the is not running. */ |
| static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk, |
| struct llist_node **cur) |
| { |
| struct kretprobe_instance *ri = NULL; |
| struct llist_node *node = *cur; |
| |
| if (!node) |
| node = tsk->kretprobe_instances.first; |
| else |
| node = node->next; |
| |
| while (node) { |
| ri = container_of(node, struct kretprobe_instance, llist); |
| if (ri->ret_addr != kretprobe_trampoline_addr()) { |
| *cur = node; |
| return ri->ret_addr; |
| } |
| node = node->next; |
| } |
| return NULL; |
| } |
| NOKPROBE_SYMBOL(__kretprobe_find_ret_addr); |
| |
| /** |
| * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe |
| * @tsk: Target task |
| * @fp: A frame pointer |
| * @cur: a storage of the loop cursor llist_node pointer for next call |
| * |
| * Find the correct return address modified by a kretprobe on @tsk in unsigned |
| * long type. If it finds the return address, this returns that address value, |
| * or this returns 0. |
| * The @tsk must be 'current' or a task which is not running. @fp is a hint |
| * to get the currect return address - which is compared with the |
| * kretprobe_instance::fp field. The @cur is a loop cursor for searching the |
| * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the |
| * first call, but '@cur' itself must NOT NULL. |
| */ |
| unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, |
| struct llist_node **cur) |
| { |
| struct kretprobe_instance *ri; |
| kprobe_opcode_t *ret; |
| |
| if (WARN_ON_ONCE(!cur)) |
| return 0; |
| |
| do { |
| ret = __kretprobe_find_ret_addr(tsk, cur); |
| if (!ret) |
| break; |
| ri = container_of(*cur, struct kretprobe_instance, llist); |
| } while (ri->fp != fp); |
| |
| return (unsigned long)ret; |
| } |
| NOKPROBE_SYMBOL(kretprobe_find_ret_addr); |
| |
| void __weak arch_kretprobe_fixup_return(struct pt_regs *regs, |
| kprobe_opcode_t *correct_ret_addr) |
| { |
| /* |
| * Do nothing by default. Please fill this to update the fake return |
| * address on the stack with the correct one on each arch if possible. |
| */ |
| } |
| |
| unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, |
| void *frame_pointer) |
| { |
| struct kretprobe_instance *ri = NULL; |
| struct llist_node *first, *node = NULL; |
| kprobe_opcode_t *correct_ret_addr; |
| struct kretprobe *rp; |
| |
| /* Find correct address and all nodes for this frame. */ |
| correct_ret_addr = __kretprobe_find_ret_addr(current, &node); |
| if (!correct_ret_addr) { |
| pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n"); |
| BUG_ON(1); |
| } |
| |
| /* |
| * Set the return address as the instruction pointer, because if the |
| * user handler calls stack_trace_save_regs() with this 'regs', |
| * the stack trace will start from the instruction pointer. |
| */ |
| instruction_pointer_set(regs, (unsigned long)correct_ret_addr); |
| |
| /* Run the user handler of the nodes. */ |
| first = current->kretprobe_instances.first; |
| while (first) { |
| ri = container_of(first, struct kretprobe_instance, llist); |
| |
| if (WARN_ON_ONCE(ri->fp != frame_pointer)) |
| break; |
| |
| rp = get_kretprobe(ri); |
| if (rp && rp->handler) { |
| struct kprobe *prev = kprobe_running(); |
| |
| __this_cpu_write(current_kprobe, &rp->kp); |
| ri->ret_addr = correct_ret_addr; |
| rp->handler(ri, regs); |
| __this_cpu_write(current_kprobe, prev); |
| } |
| if (first == node) |
| break; |
| |
| first = first->next; |
| } |
| |
| arch_kretprobe_fixup_return(regs, correct_ret_addr); |
| |
| /* Unlink all nodes for this frame. */ |
| first = current->kretprobe_instances.first; |
| current->kretprobe_instances.first = node->next; |
| node->next = NULL; |
| |
| /* Recycle free instances. */ |
| while (first) { |
| ri = container_of(first, struct kretprobe_instance, llist); |
| first = first->next; |
| |
| recycle_rp_inst(ri); |
| } |
| |
| return (unsigned long)correct_ret_addr; |
| } |
| NOKPROBE_SYMBOL(__kretprobe_trampoline_handler) |
| |
| /* |
| * This kprobe pre_handler is registered with every kretprobe. When probe |
| * hits it will set up the return probe. |
| */ |
| static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
| struct kretprobe_holder *rph = rp->rph; |
| struct kretprobe_instance *ri; |
| |
| ri = objpool_pop(&rph->pool); |
| if (!ri) { |
| rp->nmissed++; |
| return 0; |
| } |
| |
| if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
| objpool_push(ri, &rph->pool); |
| return 0; |
| } |
| |
| arch_prepare_kretprobe(ri, regs); |
| |
| __llist_add(&ri->llist, ¤t->kretprobe_instances); |
| |
| return 0; |
| } |
| NOKPROBE_SYMBOL(pre_handler_kretprobe); |
| #else /* CONFIG_KRETPROBE_ON_RETHOOK */ |
| /* |
| * This kprobe pre_handler is registered with every kretprobe. When probe |
| * hits it will set up the return probe. |
| */ |
| static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
| struct kretprobe_instance *ri; |
| struct rethook_node *rhn; |
| |
| rhn = rethook_try_get(rp->rh); |
| if (!rhn) { |
| rp->nmissed++; |
| return 0; |
| } |
| |
| ri = container_of(rhn, struct kretprobe_instance, node); |
| |
| if (rp->entry_handler && rp->entry_handler(ri, regs)) |
| rethook_recycle(rhn); |
| else |
| rethook_hook(rhn, regs, kprobe_ftrace(p)); |
| |
| return 0; |
| } |
| NOKPROBE_SYMBOL(pre_handler_kretprobe); |
| |
| static void kretprobe_rethook_handler(struct rethook_node *rh, void *data, |
| unsigned long ret_addr, |
| struct pt_regs *regs) |
| { |
| struct kretprobe *rp = (struct kretprobe *)data; |
| struct kretprobe_instance *ri; |
| struct kprobe_ctlblk *kcb; |
| |
| /* The data must NOT be null. This means rethook data structure is broken. */ |
| if (WARN_ON_ONCE(!data) || !rp->handler) |
| return; |
| |
| __this_cpu_write(current_kprobe, &rp->kp); |
| kcb = get_kprobe_ctlblk(); |
| kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
| |
| ri = container_of(rh, struct kretprobe_instance, node); |
| rp->handler(ri, regs); |
| |
| __this_cpu_write(current_kprobe, NULL); |
| } |
| NOKPROBE_SYMBOL(kretprobe_rethook_handler); |
| |
| #endif /* !CONFIG_KRETPROBE_ON_RETHOOK */ |
| |
| /** |
| * kprobe_on_func_entry() -- check whether given address is function entry |
| * @addr: Target address |
| * @sym: Target symbol name |
| * @offset: The offset from the symbol or the address |
| * |
| * This checks whether the given @addr+@offset or @sym+@offset is on the |
| * function entry address or not. |
| * This returns 0 if it is the function entry, or -EINVAL if it is not. |
| * And also it returns -ENOENT if it fails the symbol or address lookup. |
| * Caller must pass @addr or @sym (either one must be NULL), or this |
| * returns -EINVAL. |
| */ |
| int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) |
| { |
| bool on_func_entry; |
| kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry); |
| |
| if (IS_ERR(kp_addr)) |
| return PTR_ERR(kp_addr); |
| |
| if (!on_func_entry) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| int register_kretprobe(struct kretprobe *rp) |
| { |
| int ret; |
| int i; |
| void *addr; |
| |
| ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset); |
| if (ret) |
| return ret; |
| |
| /* If only 'rp->kp.addr' is specified, check reregistering kprobes */ |
| if (rp->kp.addr && warn_kprobe_rereg(&rp->kp)) |
| return -EINVAL; |
| |
| if (kretprobe_blacklist_size) { |
| addr = kprobe_addr(&rp->kp); |
| if (IS_ERR(addr)) |
| return PTR_ERR(addr); |
| |
| for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
| if (kretprobe_blacklist[i].addr == addr) |
| return -EINVAL; |
| } |
| } |
| |
| if (rp->data_size > KRETPROBE_MAX_DATA_SIZE) |
| return -E2BIG; |
| |
| rp->kp.pre_handler = pre_handler_kretprobe; |
| rp->kp.post_handler = NULL; |
| |
| /* Pre-allocate memory for max kretprobe instances */ |
| if (rp->maxactive <= 0) |
| rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
| |
| #ifdef CONFIG_KRETPROBE_ON_RETHOOK |
| rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler, |
| sizeof(struct kretprobe_instance) + |
| rp->data_size, rp->maxactive); |
| if (IS_ERR(rp->rh)) |
| return PTR_ERR(rp->rh); |
| |
| rp->nmissed = 0; |
| /* Establish function entry probe point */ |
| ret = register_kprobe(&rp->kp); |
| if (ret != 0) { |
| rethook_free(rp->rh); |
| rp->rh = NULL; |
| } |
| #else /* !CONFIG_KRETPROBE_ON_RETHOOK */ |
| rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL); |
| if (!rp->rph) |
| return -ENOMEM; |
| |
| if (objpool_init(&rp->rph->pool, rp->maxactive, rp->data_size + |
| sizeof(struct kretprobe_instance), GFP_KERNEL, |
| rp->rph, kretprobe_init_inst, kretprobe_fini_pool)) { |
| kfree(rp->rph); |
| rp->rph = NULL; |
| return -ENOMEM; |
| } |
| rcu_assign_pointer(rp->rph->rp, rp); |
| rp->nmissed = 0; |
| /* Establish function entry probe point */ |
| ret = register_kprobe(&rp->kp); |
| if (ret != 0) |
| free_rp_inst(rp); |
| #endif |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobe); |
| |
| int register_kretprobes(struct kretprobe **rps, int num) |
| { |
| int ret = 0, i; |
| |
| if (num <= 0) |
| return -EINVAL; |
| for (i = 0; i < num; i++) { |
| ret = register_kretprobe(rps[i]); |
| if (ret < 0) { |
| if (i > 0) |
| unregister_kretprobes(rps, i); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobes); |
| |
| void unregister_kretprobe(struct kretprobe *rp) |
| { |
| unregister_kretprobes(&rp, 1); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobe); |
| |
| void unregister_kretprobes(struct kretprobe **rps, int num) |
| { |
| int i; |
| |
| if (num <= 0) |
| return; |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < num; i++) { |
| if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
| rps[i]->kp.addr = NULL; |
| #ifdef CONFIG_KRETPROBE_ON_RETHOOK |
| rethook_free(rps[i]->rh); |
| #else |
| rcu_assign_pointer(rps[i]->rph->rp, NULL); |
| #endif |
| } |
| mutex_unlock(&kprobe_mutex); |
| |
| synchronize_rcu(); |
| for (i = 0; i < num; i++) { |
| if (rps[i]->kp.addr) { |
| __unregister_kprobe_bottom(&rps[i]->kp); |
| #ifndef CONFIG_KRETPROBE_ON_RETHOOK |
| free_rp_inst(rps[i]); |
| #endif |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobes); |
| |
| #else /* CONFIG_KRETPROBES */ |
| int register_kretprobe(struct kretprobe *rp) |
| { |
| return -EOPNOTSUPP; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobe); |
| |
| int register_kretprobes(struct kretprobe **rps, int num) |
| { |
| return -EOPNOTSUPP; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobes); |
| |
| void unregister_kretprobe(struct kretprobe *rp) |
| { |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobe); |
| |
| void unregister_kretprobes(struct kretprobe **rps, int num) |
| { |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobes); |
| |
| static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
| { |
| return 0; |
| } |
| NOKPROBE_SYMBOL(pre_handler_kretprobe); |
| |
| #endif /* CONFIG_KRETPROBES */ |
| |
| /* Set the kprobe gone and remove its instruction buffer. */ |
| static void kill_kprobe(struct kprobe *p) |
| { |
| struct kprobe *kp; |
| |
| lockdep_assert_held(&kprobe_mutex); |
| |
| /* |
| * The module is going away. We should disarm the kprobe which |
| * is using ftrace, because ftrace framework is still available at |
| * 'MODULE_STATE_GOING' notification. |
| */ |
| if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed) |
| disarm_kprobe_ftrace(p); |
| |
| p->flags |= KPROBE_FLAG_GONE; |
| if (kprobe_aggrprobe(p)) { |
| /* |
| * If this is an aggr_kprobe, we have to list all the |
| * chained probes and mark them GONE. |
| */ |
| list_for_each_entry(kp, &p->list, list) |
| kp->flags |= KPROBE_FLAG_GONE; |
| p->post_handler = NULL; |
| kill_optimized_kprobe(p); |
| } |
| /* |
| * Here, we can remove insn_slot safely, because no thread calls |
| * the original probed function (which will be freed soon) any more. |
| */ |
| arch_remove_kprobe(p); |
| } |
| |
| /* Disable one kprobe */ |
| int disable_kprobe(struct kprobe *kp) |
| { |
| int ret = 0; |
| struct kprobe *p; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* Disable this kprobe */ |
| p = __disable_kprobe(kp); |
| if (IS_ERR(p)) |
| ret = PTR_ERR(p); |
| |
| mutex_unlock(&kprobe_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(disable_kprobe); |
| |
| /* Enable one kprobe */ |
| int enable_kprobe(struct kprobe *kp) |
| { |
| int ret = 0; |
| struct kprobe *p; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* Check whether specified probe is valid. */ |
| p = __get_valid_kprobe(kp); |
| if (unlikely(p == NULL)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (kprobe_gone(kp)) { |
| /* This kprobe has gone, we couldn't enable it. */ |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (p != kp) |
| kp->flags &= ~KPROBE_FLAG_DISABLED; |
| |
| if (!kprobes_all_disarmed && kprobe_disabled(p)) { |
| p->flags &= ~KPROBE_FLAG_DISABLED; |
| ret = arm_kprobe(p); |
| if (ret) { |
| p->flags |= KPROBE_FLAG_DISABLED; |
| if (p != kp) |
| kp->flags |= KPROBE_FLAG_DISABLED; |
| } |
| } |
| out: |
| mutex_unlock(&kprobe_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(enable_kprobe); |
| |
| /* Caller must NOT call this in usual path. This is only for critical case */ |
| void dump_kprobe(struct kprobe *kp) |
| { |
| pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n", |
| kp->symbol_name, kp->offset, kp->addr); |
| } |
| NOKPROBE_SYMBOL(dump_kprobe); |
| |
| int kprobe_add_ksym_blacklist(unsigned long entry) |
| { |
| struct kprobe_blacklist_entry *ent; |
| unsigned long offset = 0, size = 0; |
| |
| if (!kernel_text_address(entry) || |
| !kallsyms_lookup_size_offset(entry, &size, &offset)) |
| return -EINVAL; |
| |
| ent = kmalloc(sizeof(*ent), GFP_KERNEL); |
| if (!ent) |
| return -ENOMEM; |
| ent->start_addr = entry; |
| ent->end_addr = entry + size; |
| INIT_LIST_HEAD(&ent->list); |
| list_add_tail(&ent->list, &kprobe_blacklist); |
| |
| return (int)size; |
| } |
| |
| /* Add all symbols in given area into kprobe blacklist */ |
| int kprobe_add_area_blacklist(unsigned long start, unsigned long end) |
| { |
| unsigned long entry; |
| int ret = 0; |
| |
| for (entry = start; entry < end; entry += ret) { |
| ret = kprobe_add_ksym_blacklist(entry); |
| if (ret < 0) |
| return ret; |
| if (ret == 0) /* In case of alias symbol */ |
| ret = 1; |
| } |
| return 0; |
| } |
| |
| int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, |
| char *type, char *sym) |
| { |
| return -ERANGE; |
| } |
| |
| int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, |
| char *sym) |
| { |
| #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
| if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym)) |
| return 0; |
| #ifdef CONFIG_OPTPROBES |
| if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym)) |
| return 0; |
| #endif |
| #endif |
| if (!arch_kprobe_get_kallsym(&symnum, value, type, sym)) |
| return 0; |
| return -ERANGE; |
| } |
| |
| int __init __weak arch_populate_kprobe_blacklist(void) |
| { |
| return 0; |
| } |
| |
| /* |
| * Lookup and populate the kprobe_blacklist. |
| * |
| * Unlike the kretprobe blacklist, we'll need to determine |
| * the range of addresses that belong to the said functions, |
| * since a kprobe need not necessarily be at the beginning |
| * of a function. |
| */ |
| static int __init populate_kprobe_blacklist(unsigned long *start, |
| unsigned long *end) |
| { |
| unsigned long entry; |
| unsigned long *iter; |
| int ret; |
| |
| for (iter = start; iter < end; iter++) { |
| entry = (unsigned long)dereference_symbol_descriptor((void *)*iter); |
| ret = kprobe_add_ksym_blacklist(entry); |
| if (ret == -EINVAL) |
| continue; |
| if (ret < 0) |
| return ret; |
| } |
| |
| /* Symbols in '__kprobes_text' are blacklisted */ |
| ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, |
| (unsigned long)__kprobes_text_end); |
| if (ret) |
| return ret; |
| |
| /* Symbols in 'noinstr' section are blacklisted */ |
| ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start, |
| (unsigned long)__noinstr_text_end); |
| |
| return ret ? : arch_populate_kprobe_blacklist(); |
| } |
| |
| #ifdef CONFIG_MODULES |
| /* Remove all symbols in given area from kprobe blacklist */ |
| static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) |
| { |
| struct kprobe_blacklist_entry *ent, *n; |
| |
| list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { |
| if (ent->start_addr < start || ent->start_addr >= end) |
| continue; |
| list_del(&ent->list); |
| kfree(ent); |
| } |
| } |
| |
| static void kprobe_remove_ksym_blacklist(unsigned long entry) |
| { |
| kprobe_remove_area_blacklist(entry, entry + 1); |
| } |
| |
| static void add_module_kprobe_blacklist(struct module *mod) |
| { |
| unsigned long start, end; |
| int i; |
| |
| if (mod->kprobe_blacklist) { |
| for (i = 0; i < mod->num_kprobe_blacklist; i++) |
| kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]); |
| } |
| |
| start = (unsigned long)mod->kprobes_text_start; |
| if (start) { |
| end = start + mod->kprobes_text_size; |
| kprobe_add_area_blacklist(start, end); |
| } |
| |
| start = (unsigned long)mod->noinstr_text_start; |
| if (start) { |
| end = start + mod->noinstr_text_size; |
| kprobe_add_area_blacklist(start, end); |
| } |
| } |
| |
| static void remove_module_kprobe_blacklist(struct module *mod) |
| { |
| unsigned long start, end; |
| int i; |
| |
| if (mod->kprobe_blacklist) { |
| for (i = 0; i < mod->num_kprobe_blacklist; i++) |
| kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]); |
| } |
| |
| start = (unsigned long)mod->kprobes_text_start; |
| if (start) { |
| end = start + mod->kprobes_text_size; |
| kprobe_remove_area_blacklist(start, end); |
| } |
| |
| start = (unsigned long)mod->noinstr_text_start; |
| if (start) { |
| end = start + mod->noinstr_text_size; |
| kprobe_remove_area_blacklist(start, end); |
| } |
| } |
| |
| /* Module notifier call back, checking kprobes on the module */ |
| static int kprobes_module_callback(struct notifier_block *nb, |
| unsigned long val, void *data) |
| { |
| struct module *mod = data; |
| struct hlist_head *head; |
| struct kprobe *p; |
| unsigned int i; |
| int checkcore = (val == MODULE_STATE_GOING); |
| |
| if (val == MODULE_STATE_COMING) { |
| mutex_lock(&kprobe_mutex); |
| add_module_kprobe_blacklist(mod); |
| mutex_unlock(&kprobe_mutex); |
| } |
| if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
| return NOTIFY_DONE; |
| |
| /* |
| * When 'MODULE_STATE_GOING' was notified, both of module '.text' and |
| * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was |
| * notified, only '.init.text' section would be freed. We need to |
| * disable kprobes which have been inserted in the sections. |
| */ |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry(p, head, hlist) |
| if (within_module_init((unsigned long)p->addr, mod) || |
| (checkcore && |
| within_module_core((unsigned long)p->addr, mod))) { |
| /* |
| * The vaddr this probe is installed will soon |
| * be vfreed buy not synced to disk. Hence, |
| * disarming the breakpoint isn't needed. |
| * |
| * Note, this will also move any optimized probes |
| * that are pending to be removed from their |
| * corresponding lists to the 'freeing_list' and |
| * will not be touched by the delayed |
| * kprobe_optimizer() work handler. |
| */ |
| kill_kprobe(p); |
| } |
| } |
| if (val == MODULE_STATE_GOING) |
| remove_module_kprobe_blacklist(mod); |
| mutex_unlock(&kprobe_mutex); |
| return NOTIFY_DONE; |
| } |
| |
| static struct notifier_block kprobe_module_nb = { |
| .notifier_call = kprobes_module_callback, |
| .priority = 0 |
| }; |
| |
| static int kprobe_register_module_notifier(void) |
| { |
| return register_module_notifier(&kprobe_module_nb); |
| } |
| #else |
| static int kprobe_register_module_notifier(void) |
| { |
| return 0; |
| } |
| #endif /* CONFIG_MODULES */ |
| |
| void kprobe_free_init_mem(void) |
| { |
| void *start = (void *)(&__init_begin); |
| void *end = (void *)(&__init_end); |
| struct hlist_head *head; |
| struct kprobe *p; |
| int i; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* Kill all kprobes on initmem because the target code has been freed. */ |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry(p, head, hlist) { |
| if (start <= (void *)p->addr && (void *)p->addr < end) |
| kill_kprobe(p); |
| } |
| } |
| |
| mutex_unlock(&kprobe_mutex); |
| } |
| |
| static int __init init_kprobes(void) |
| { |
| int i, err; |
| |
| /* FIXME allocate the probe table, currently defined statically */ |
| /* initialize all list heads */ |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) |
| INIT_HLIST_HEAD(&kprobe_table[i]); |
| |
| err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
| __stop_kprobe_blacklist); |
| if (err) |
| pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err); |
| |
| if (kretprobe_blacklist_size) { |
| /* lookup the function address from its name */ |
| for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
| kretprobe_blacklist[i].addr = |
| kprobe_lookup_name(kretprobe_blacklist[i].name, 0); |
| if (!kretprobe_blacklist[i].addr) |
| pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n", |
| kretprobe_blacklist[i].name); |
| } |
| } |
| |
| /* By default, kprobes are armed */ |
| kprobes_all_disarmed = false; |
| |
| #if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
| /* Init 'kprobe_optinsn_slots' for allocation */ |
| kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
| #endif |
| |
| err = arch_init_kprobes(); |
| if (!err) |
| err = register_die_notifier(&kprobe_exceptions_nb); |
| if (!err) |
| err = kprobe_register_module_notifier(); |
| |
| kprobes_initialized = (err == 0); |
| kprobe_sysctls_init(); |
| return err; |
| } |
| early_initcall(init_kprobes); |
| |
| #if defined(CONFIG_OPTPROBES) |
| static int __init init_optprobes(void) |
| { |
| /* |
| * Enable kprobe optimization - this kicks the optimizer which |
| * depends on synchronize_rcu_tasks() and ksoftirqd, that is |
| * not spawned in early initcall. So delay the optimization. |
| */ |
| optimize_all_kprobes(); |
| |
| return 0; |
| } |
| subsys_initcall(init_optprobes); |
| #endif |
| |
| #ifdef CONFIG_DEBUG_FS |
| static void report_probe(struct seq_file *pi, struct kprobe *p, |
| const char *sym, int offset, char *modname, struct kprobe *pp) |
| { |
| char *kprobe_type; |
| void *addr = p->addr; |
| |
| if (p->pre_handler == pre_handler_kretprobe) |
| kprobe_type = "r"; |
| else |
| kprobe_type = "k"; |
| |
| if (!kallsyms_show_value(pi->file->f_cred)) |
| addr = NULL; |
| |
| if (sym) |
| seq_printf(pi, "%px %s %s+0x%x %s ", |
| addr, kprobe_type, sym, offset, |
| (modname ? modname : " ")); |
| else /* try to use %pS */ |
| seq_printf(pi, "%px %s %pS ", |
| addr, kprobe_type, p->addr); |
| |
| if (!pp) |
| pp = p; |
| seq_printf(pi, "%s%s%s%s\n", |
| (kprobe_gone(p) ? "[GONE]" : ""), |
| ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
| (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
| (kprobe_ftrace(pp) ? "[FTRACE]" : "")); |
| } |
| |
| static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
| { |
| return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
| } |
| |
| static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
| { |
| (*pos)++; |
| if (*pos >= KPROBE_TABLE_SIZE) |
| return NULL; |
| return pos; |
| } |
| |
| static void kprobe_seq_stop(struct seq_file *f, void *v) |
| { |
| /* Nothing to do */ |
| } |
| |
| static int show_kprobe_addr(struct seq_file *pi, void *v) |
| { |
| struct hlist_head *head; |
| struct kprobe *p, *kp; |
| const char *sym; |
| unsigned int i = *(loff_t *) v; |
| unsigned long offset = 0; |
| char *modname, namebuf[KSYM_NAME_LEN]; |
| |
| head = &kprobe_table[i]; |
| preempt_disable(); |
| hlist_for_each_entry_rcu(p, head, hlist) { |
| sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
| &offset, &modname, namebuf); |
| if (kprobe_aggrprobe(p)) { |
| list_for_each_entry_rcu(kp, &p->list, list) |
| report_probe(pi, kp, sym, offset, modname, p); |
| } else |
| report_probe(pi, p, sym, offset, modname, NULL); |
| } |
| preempt_enable(); |
| return 0; |
| } |
| |
| static const struct seq_operations kprobes_sops = { |
| .start = kprobe_seq_start, |
| .next = kprobe_seq_next, |
| .stop = kprobe_seq_stop, |
| .show = show_kprobe_addr |
| }; |
| |
| DEFINE_SEQ_ATTRIBUTE(kprobes); |
| |
| /* kprobes/blacklist -- shows which functions can not be probed */ |
| static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) |
| { |
| mutex_lock(&kprobe_mutex); |
| return seq_list_start(&kprobe_blacklist, *pos); |
| } |
| |
| static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) |
| { |
| return seq_list_next(v, &kprobe_blacklist, pos); |
| } |
| |
| static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) |
| { |
| struct kprobe_blacklist_entry *ent = |
| list_entry(v, struct kprobe_blacklist_entry, list); |
| |
| /* |
| * If '/proc/kallsyms' is not showing kernel address, we won't |
| * show them here either. |
| */ |
| if (!kallsyms_show_value(m->file->f_cred)) |
| seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, |
| (void *)ent->start_addr); |
| else |
| seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr, |
| (void *)ent->end_addr, (void *)ent->start_addr); |
| return 0; |
| } |
| |
| static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v) |
| { |
| mutex_unlock(&kprobe_mutex); |
| } |
| |
| static const struct seq_operations kprobe_blacklist_sops = { |
| .start = kprobe_blacklist_seq_start, |
| .next = kprobe_blacklist_seq_next, |
| .stop = kprobe_blacklist_seq_stop, |
| .show = kprobe_blacklist_seq_show, |
| }; |
| DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist); |
| |
| static int arm_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct kprobe *p; |
| unsigned int i, total = 0, errors = 0; |
| int err, ret = 0; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* If kprobes are armed, just return */ |
| if (!kprobes_all_disarmed) |
| goto already_enabled; |
| |
| /* |
| * optimize_kprobe() called by arm_kprobe() checks |
| * kprobes_all_disarmed, so set kprobes_all_disarmed before |
| * arm_kprobe. |
| */ |
| kprobes_all_disarmed = false; |
| /* Arming kprobes doesn't optimize kprobe itself */ |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| /* Arm all kprobes on a best-effort basis */ |
| hlist_for_each_entry(p, head, hlist) { |
| if (!kprobe_disabled(p)) { |
| err = arm_kprobe(p); |
| if (err) { |
| errors++; |
| ret = err; |
| } |
| total++; |
| } |
| } |
| } |
| |
| if (errors) |
| pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n", |
| errors, total); |
| else |
| pr_info("Kprobes globally enabled\n"); |
| |
| already_enabled: |
| mutex_unlock(&kprobe_mutex); |
| return ret; |
| } |
| |
| static int disarm_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct kprobe *p; |
| unsigned int i, total = 0, errors = 0; |
| int err, ret = 0; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* If kprobes are already disarmed, just return */ |
| if (kprobes_all_disarmed) { |
| mutex_unlock(&kprobe_mutex); |
| return 0; |
| } |
| |
| kprobes_all_disarmed = true; |
| |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| /* Disarm all kprobes on a best-effort basis */ |
| hlist_for_each_entry(p, head, hlist) { |
| if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { |
| err = disarm_kprobe(p, false); |
| if (err) { |
| errors++; |
| ret = err; |
| } |
| total++; |
| } |
| } |
| } |
| |
| if (errors) |
| pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n", |
| errors, total); |
| else |
| pr_info("Kprobes globally disabled\n"); |
| |
| mutex_unlock(&kprobe_mutex); |
| |
| /* Wait for disarming all kprobes by optimizer */ |
| wait_for_kprobe_optimizer(); |
| |
| return ret; |
| } |
| |
| /* |
| * XXX: The debugfs bool file interface doesn't allow for callbacks |
| * when the bool state is switched. We can reuse that facility when |
| * available |
| */ |
| static ssize_t read_enabled_file_bool(struct file *file, |
| char __user *user_buf, size_t count, loff_t *ppos) |
| { |
| char buf[3]; |
| |
| if (!kprobes_all_disarmed) |
| buf[0] = '1'; |
| else |
| buf[0] = '0'; |
| buf[1] = '\n'; |
| buf[2] = 0x00; |
| return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
| } |
| |
| static ssize_t write_enabled_file_bool(struct file *file, |
| const char __user *user_buf, size_t count, loff_t *ppos) |
| { |
| bool enable; |
| int ret; |
| |
| ret = kstrtobool_from_user(user_buf, count, &enable); |
| if (ret) |
| return ret; |
| |
| ret = enable ? arm_all_kprobes() : disarm_all_kprobes(); |
| if (ret) |
| return ret; |
| |
| return count; |
| } |
| |
| static const struct file_operations fops_kp = { |
| .read = read_enabled_file_bool, |
| .write = write_enabled_file_bool, |
| .llseek = default_llseek, |
| }; |
| |
| static int __init debugfs_kprobe_init(void) |
| { |
| struct dentry *dir; |
| |
| dir = debugfs_create_dir("kprobes", NULL); |
| |
| debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops); |
| |
| debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp); |
| |
| debugfs_create_file("blacklist", 0400, dir, NULL, |
| &kprobe_blacklist_fops); |
| |
| return 0; |
| } |
| |
| late_initcall(debugfs_kprobe_init); |
| #endif /* CONFIG_DEBUG_FS */ |