From 19b057aaa73cc503c448510e746f1edeaa2034ae Mon Sep 17 00:00:00 2001 From: Vyacheslav Cherkashin Date: Mon, 26 May 2014 14:24:59 +0400 Subject: [PATCH] [IMPROVE] x86: create kjumper Change-Id: I1eb683b443df2ec0ae340649758e0359edf4c4c2 Signed-off-by: Vyacheslav Cherkashin --- kprobe/arch/asm-x86/swap_kprobes.c | 238 ++++++++++++++++++++++++++----------- kprobe/arch/asm-x86/swap_kprobes.h | 6 + 2 files changed, 176 insertions(+), 68 deletions(-) diff --git a/kprobe/arch/asm-x86/swap_kprobes.c b/kprobe/arch/asm-x86/swap_kprobes.c index 813d023..d302ca9 100644 --- a/kprobe/arch/asm-x86/swap_kprobes.c +++ b/kprobe/arch/asm-x86/swap_kprobes.c @@ -321,37 +321,42 @@ void set_current_kprobe (struct kprobe *p, struct pt_regs *regs, struct kprobe_c kcb->kprobe_saved_eflags &= ~IF_MASK; } -/** - * @brief Kprobe handler. - * - * @param regs Pointer to CPU register data. - * @return 1 on success. - */ -int kprobe_handler (struct pt_regs *regs) +static int setup_singlestep(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ +#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM) + if (p->ainsn.boostable == 1 && !p->post_handler) { + /* Boost up -- we can execute copied instructions directly */ + swap_reset_current_kprobe(); + regs->ip = (unsigned long)p->ainsn.insn; + preempt_enable_no_resched(); + + return 1; + } +#endif // !CONFIG_PREEMPT + + prepare_singlestep(p, regs); + kcb->kprobe_status = KPROBE_HIT_SS; + + return 1; +} + +static int __kprobe_handler(struct pt_regs *regs) { struct kprobe *p = 0; int ret = 0, reenter = 0; kprobe_opcode_t *addr = NULL; struct kprobe_ctlblk *kcb; -#ifdef SUPRESS_BUG_MESSAGES - int swap_oops_in_progress; -#endif - /* We're in an interrupt, but this is clear and BUG()-safe. */ addr = (kprobe_opcode_t *) (regs->EREG (ip) - sizeof (kprobe_opcode_t)); - DBPRINTF ("KPROBE: regs->eip = 0x%lx addr = 0x%p\n", regs->EREG (ip), addr); -#ifdef SUPRESS_BUG_MESSAGES - // oops_in_progress used to avoid BUG() messages that slow down kprobe_handler() execution - swap_oops_in_progress = oops_in_progress; - oops_in_progress = 1; -#endif + preempt_disable (); kcb = swap_get_kprobe_ctlblk(); + p = swap_get_kprobe(addr); /* Check we're not actually recursing */ if (swap_kprobe_running()) { - p = swap_get_kprobe(addr); if (p) { if (kcb->kprobe_status == KPROBE_HIT_SS && *p->ainsn.insn == BREAKPOINT_INSTRUCTION) { regs->EREG(flags) &= ~TF_MASK; @@ -371,11 +376,7 @@ int kprobe_handler (struct pt_regs *regs) swap_kprobes_inc_nmissed_count(p); prepare_singlestep (p, regs); kcb->kprobe_status = KPROBE_REENTER; - // FIXME should we enable preemption here??... - //preempt_enable_no_resched (); -#ifdef SUPRESS_BUG_MESSAGES - oops_in_progress = swap_oops_in_progress; -#endif + return 1; } else { if (*addr != BREAKPOINT_INSTRUCTION) { @@ -396,9 +397,6 @@ int kprobe_handler (struct pt_regs *regs) } } - if (!p) - p = swap_get_kprobe(addr); - if (!p) { if (*addr != BREAKPOINT_INSTRUCTION) { /* @@ -426,59 +424,42 @@ int kprobe_handler (struct pt_regs *regs) if(!reenter) kcb->kprobe_status = KPROBE_HIT_ACTIVE; - if (p->pre_handler) + if (p->pre_handler) { ret = p->pre_handler(p, regs); - - if (ret) - { - if (ret == 2) { // we have alreadyc called the handler, so just single step the instruction - DBPRINTF ("p->pre_handler[] 2"); - goto ss_probe; - } - DBPRINTF ("p->pre_handler[] 1"); - // FIXME should we enable preemption here??... - //preempt_enable_no_resched (); -#ifdef SUPRESS_BUG_MESSAGES - oops_in_progress = swap_oops_in_progress; -#endif - /* handler has already set things up, so skip ss setup */ - prepare_singlestep(p, regs); - return 1; + if (ret) + return ret; } - DBPRINTF ("p->pre_handler[] 0"); ss_probe: - DBPRINTF ("p = %p\n", p); - DBPRINTF ("p->opcode = 0x%lx *p->addr = 0x%lx p->addr = 0x%p\n", (unsigned long) p->opcode, p->tgid ? 0 : (unsigned long) (*p->addr), p->addr); + setup_singlestep(p, regs, kcb); -#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM) - if (p->ainsn.boostable == 1 && !p->post_handler) - { - /* Boost up -- we can execute copied instructions directly */ - swap_reset_current_kprobe(); - regs->EREG (ip) = (unsigned long) p->ainsn.insn; - preempt_enable_no_resched (); -#ifdef SUPRESS_BUG_MESSAGES - oops_in_progress = swap_oops_in_progress; -#endif - return 1; - } -#endif // !CONFIG_PREEMPT - prepare_singlestep (p, regs); - kcb->kprobe_status = KPROBE_HIT_SS; - // FIXME should we enable preemption here??... - //preempt_enable_no_resched (); -#ifdef SUPRESS_BUG_MESSAGES - oops_in_progress = swap_oops_in_progress; -#endif return 1; no_kprobe: - preempt_enable_no_resched (); + + return ret; +} + +static int kprobe_handler(struct pt_regs *regs) +{ + int ret; +#ifdef SUPRESS_BUG_MESSAGES + int swap_oops_in_progress; + /* + * oops_in_progress used to avoid BUG() messages + * that slow down kprobe_handler() execution + */ + swap_oops_in_progress = oops_in_progress; + oops_in_progress = 1; +#endif + + ret = __kprobe_handler(regs); + #ifdef SUPRESS_BUG_MESSAGES oops_in_progress = swap_oops_in_progress; #endif + return ret; } @@ -904,6 +885,116 @@ void swap_arch_prepare_kretprobe(struct kretprobe_instance *ri, *ptr_ret_addr = (unsigned long)&swap_kretprobe_trampoline; } + + + + +/* + ****************************************************************************** + * kjumper * + ****************************************************************************** + */ +struct kj_cb_data { + struct pt_regs regs; + struct kprobe *p; + + jumper_cb_t cb; + char data[0]; +}; + +static struct kj_cb_data * __used kjump_handler(struct kj_cb_data *data) +{ + /* call callback */ + data->cb(data->data); + + return data; +} + +void kjump_trampoline(void); +void kjump_trampoline_int3(void); +__asm( + "kjump_trampoline: \n" + "call kjump_handler \n" + "kjump_trampoline_int3: \n" + "nop \n" /* for restore_regs_kp */ +); + +int set_kjump_cb(struct pt_regs *regs, jumper_cb_t cb, void *data, size_t size) +{ + struct kj_cb_data *cb_data; + + cb_data = kmalloc(sizeof(*cb_data) + size, GFP_ATOMIC); + if (cb_data == NULL) + return -ENOMEM; + + /* save regs */ + cb_data->regs = *regs; + + cb_data->p = swap_kprobe_running(); + cb_data->cb = cb; + + /* save data */ + if (size) + memcpy(cb_data->data, data, size); + + /* save pointer cb_data at ax */ + regs->ax = (long)cb_data; + + /* jump to kjump_trampoline */ + regs->ip = (unsigned long)&kjump_trampoline; + + swap_reset_current_kprobe(); + preempt_enable_no_resched(); + + return 1; +} +EXPORT_SYMBOL_GPL(set_kjump_cb); + +static int restore_regs_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + struct kj_cb_data *data = (struct kj_cb_data *)regs->ax; + struct kprobe *kp = data->p; + struct kprobe_ctlblk *kcb = swap_get_kprobe_ctlblk(); + + /* restore regs */ + *regs = data->regs; + + /* FIXME: potential memory leak, when process kill */ + kfree(data); + + kcb = swap_get_kprobe_ctlblk(); + + set_current_kprobe(kp, regs, kcb); + setup_singlestep(kp, regs, kcb); + + return 1; +} + +static struct kprobe restore_regs_kp = { + .pre_handler = restore_regs_pre_handler, + .addr = (kprobe_opcode_t *)&kjump_trampoline_int3, /* nop */ +}; + +static int kjump_init(void) +{ + int ret; + + ret = swap_register_kprobe(&restore_regs_kp); + if (ret) + printk("ERROR: kjump_init(), ret=%d\n", ret); + + return ret; +} + +static void kjump_exit(void) +{ + swap_unregister_kprobe(&restore_regs_kp); +} + + + + + /** * @brief Initializes x86 module deps. * @@ -946,7 +1037,17 @@ not_found: */ int swap_arch_init_kprobes(void) { - return register_die_notifier (&kprobe_exceptions_nb); + int ret; + + ret = register_die_notifier(&kprobe_exceptions_nb); + if (ret) + return ret; + + ret = kjump_init(); + if (ret) + unregister_die_notifier(&kprobe_exceptions_nb); + + return ret; } /** @@ -956,5 +1057,6 @@ int swap_arch_init_kprobes(void) */ void swap_arch_exit_kprobes(void) { + kjump_exit(); unregister_die_notifier (&kprobe_exceptions_nb); } diff --git a/kprobe/arch/asm-x86/swap_kprobes.h b/kprobe/arch/asm-x86/swap_kprobes.h index c7b0693..e8e7e77 100644 --- a/kprobe/arch/asm-x86/swap_kprobes.h +++ b/kprobe/arch/asm-x86/swap_kprobes.h @@ -260,6 +260,12 @@ static inline unsigned long swap_get_sarg(struct pt_regs *regs, unsigned long n) return *((unsigned long *)kernel_stack_pointer(regs) + n + 1); } +/* jumper */ +typedef unsigned long (*jumper_cb_t)(void *); + +int set_kjump_cb(struct pt_regs *regs, jumper_cb_t cb, + void *data, size_t size); + int swap_arch_init_kprobes(void); void swap_arch_exit_kprobes(void); -- 2.7.4