diff options
Diffstat (limited to '')
-rw-r--r-- | arch/x86/kernel/kprobes/core.c | 156 |
1 files changed, 31 insertions, 125 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index fce99e249d61..eb8bc82846b9 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -52,14 +52,13 @@ #include <asm/insn.h> #include <asm/debugreg.h> #include <asm/set_memory.h> +#include <asm/ibt.h> #include "common.h" DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); -#define stack_addr(regs) ((unsigned long *)regs->sp) - #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \ @@ -193,17 +192,10 @@ static unsigned long __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) { struct kprobe *kp; - unsigned long faddr; + bool faddr; kp = get_kprobe((void *)addr); - faddr = ftrace_location(addr); - /* - * Addresses inside the ftrace location are refused by - * arch_check_ftrace_location(). Something went terribly wrong - * if such an address is checked here. - */ - if (WARN_ON(faddr && faddr != addr)) - return 0UL; + faddr = ftrace_location(addr) == addr; /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. @@ -301,6 +293,22 @@ static int can_probe(unsigned long paddr) return (addr == paddr); } +/* If x86 supports IBT (ENDBR) it must be skipped. */ +kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, + bool *on_func_entry) +{ + if (is_endbr(*(u32 *)addr)) { + *on_func_entry = !offset || offset == 4; + if (*on_func_entry) + offset = 4; + + } else { + *on_func_entry = !offset; + } + + return (kprobe_opcode_t *)(addr + offset); +} + /* * Copy an instruction with recovering modified instruction by kprobes * and adjust the displacement if the instruction uses the %rip-relative @@ -495,7 +503,7 @@ static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs) match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^ ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT); if (p->ainsn.jcc.type >= 0xe) - match = match && (regs->flags & X86_EFLAGS_ZF); + match = match || (regs->flags & X86_EFLAGS_ZF); } __kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert)); } @@ -801,31 +809,23 @@ set_current_kprobe(struct kprobe *p, struct pt_regs *regs, = (regs->flags & X86_EFLAGS_IF); } -void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) -{ - unsigned long *sara = stack_addr(regs); - - ri->ret_addr = (kprobe_opcode_t *) *sara; - ri->fp = sara; - - /* Replace the return addr with trampoline addr */ - *sara = (unsigned long) &__kretprobe_trampoline; -} -NOKPROBE_SYMBOL(arch_prepare_kretprobe); - static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { - if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { - kcb->kprobe_status = KPROBE_HIT_SSDONE; - cur->post_handler(cur, regs, 0); - } - /* Restore back the original saved kprobes variables and continue. */ - if (kcb->kprobe_status == KPROBE_REENTER) + if (kcb->kprobe_status == KPROBE_REENTER) { + /* This will restore both kcb and current_kprobe */ restore_previous_kprobe(kcb); - else + } else { + /* + * Always update the kcb status because + * reset_curent_kprobe() doesn't update kcb. + */ + kcb->kprobe_status = KPROBE_HIT_SSDONE; + if (cur->post_handler) + cur->post_handler(cur, regs, 0); reset_current_kprobe(); + } } NOKPROBE_SYMBOL(kprobe_post_process); @@ -1013,100 +1013,6 @@ int kprobe_int3_handler(struct pt_regs *regs) } NOKPROBE_SYMBOL(kprobe_int3_handler); -/* - * When a retprobed function returns, this code saves registers and - * calls trampoline_handler() runs, which calls the kretprobe's handler. - */ -asm( - ".text\n" - ".global __kretprobe_trampoline\n" - ".type __kretprobe_trampoline, @function\n" - "__kretprobe_trampoline:\n" -#ifdef CONFIG_X86_64 - /* Push a fake return address to tell the unwinder it's a kretprobe. */ - " pushq $__kretprobe_trampoline\n" - UNWIND_HINT_FUNC - /* Save the 'sp - 8', this will be fixed later. */ - " pushq %rsp\n" - " pushfq\n" - SAVE_REGS_STRING - " movq %rsp, %rdi\n" - " call trampoline_handler\n" - RESTORE_REGS_STRING - /* In trampoline_handler(), 'regs->flags' is copied to 'regs->sp'. */ - " addq $8, %rsp\n" - " popfq\n" -#else - /* Push a fake return address to tell the unwinder it's a kretprobe. */ - " pushl $__kretprobe_trampoline\n" - UNWIND_HINT_FUNC - /* Save the 'sp - 4', this will be fixed later. */ - " pushl %esp\n" - " pushfl\n" - SAVE_REGS_STRING - " movl %esp, %eax\n" - " call trampoline_handler\n" - RESTORE_REGS_STRING - /* In trampoline_handler(), 'regs->flags' is copied to 'regs->sp'. */ - " addl $4, %esp\n" - " popfl\n" -#endif - " ret\n" - ".size __kretprobe_trampoline, .-__kretprobe_trampoline\n" -); -NOKPROBE_SYMBOL(__kretprobe_trampoline); -/* - * __kretprobe_trampoline() skips updating frame pointer. The frame pointer - * saved in trampoline_handler() points to the real caller function's - * frame pointer. Thus the __kretprobe_trampoline() doesn't have a - * standard stack frame with CONFIG_FRAME_POINTER=y. - * Let's mark it non-standard function. Anyway, FP unwinder can correctly - * unwind without the hint. - */ -STACK_FRAME_NON_STANDARD_FP(__kretprobe_trampoline); - -/* This is called from kretprobe_trampoline_handler(). */ -void arch_kretprobe_fixup_return(struct pt_regs *regs, - kprobe_opcode_t *correct_ret_addr) -{ - unsigned long *frame_pointer = ®s->sp + 1; - - /* Replace fake return address with real one. */ - *frame_pointer = (unsigned long)correct_ret_addr; -} - -/* - * Called from __kretprobe_trampoline - */ -__used __visible void trampoline_handler(struct pt_regs *regs) -{ - unsigned long *frame_pointer; - - /* fixup registers */ - regs->cs = __KERNEL_CS; -#ifdef CONFIG_X86_32 - regs->gs = 0; -#endif - regs->ip = (unsigned long)&__kretprobe_trampoline; - regs->orig_ax = ~0UL; - regs->sp += sizeof(long); - frame_pointer = ®s->sp + 1; - - /* - * The return address at 'frame_pointer' is recovered by the - * arch_kretprobe_fixup_return() which called from the - * kretprobe_trampoline_handler(). - */ - kretprobe_trampoline_handler(regs, frame_pointer); - - /* - * Copy FLAGS to 'pt_regs::sp' so that __kretprobe_trapmoline() - * can do RET right after POPF. - */ - regs->sp = regs->flags; -} -NOKPROBE_SYMBOL(trampoline_handler); - int kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); |