diff options
| -rw-r--r-- | arch/x86/kernel/kprobes.c | 33 |
1 files changed, 15 insertions, 18 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 6bec22f514b..ca6d450bee7 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -361,19 +361,15 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) * If not, return null. * Only applicable to 64-bit x86. */ -static int __kprobes __copy_instruction(u8 *dest, u8 *src, int recover) +static int __kprobes __copy_instruction(u8 *dest, u8 *src) { struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; - u8 *orig_src = src; /* Back up original src for RIP calculation */ - if (recover) - src = (u8 *)recover_probed_instruction(buf, (unsigned long)src); - - kernel_insn_init(&insn, src); + kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, (unsigned long)src)); insn_get_length(&insn); /* Another subsystem puts a breakpoint, failed to recover */ - if (recover && insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) + if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) return 0; memcpy(dest, insn.kaddr, insn.length); @@ -395,7 +391,7 @@ static int __kprobes __copy_instruction(u8 *dest, u8 *src, int recover) * extension of the original signed 32-bit displacement would * have given. */ - newdisp = (u8 *) orig_src + (s64) insn.displacement.value - (u8 *) dest; + newdisp = (u8 *) src + (s64) insn.displacement.value - (u8 *) dest; BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check. */ disp = (u8 *) dest + insn_offset_displacement(&insn); *(s32 *) disp = (s32) newdisp; @@ -406,18 +402,20 @@ static int __kprobes __copy_instruction(u8 *dest, u8 *src, int recover) static void __kprobes arch_copy_kprobe(struct kprobe *p) { + /* Copy an instruction with recovering if other optprobe modifies it.*/ + __copy_instruction(p->ainsn.insn, p->addr); + /* - * Copy an instruction without recovering int3, because it will be - * put by another subsystem. + * __copy_instruction can modify the displacement of the instruction, + * but it doesn't affect boostable check. */ - __copy_instruction(p->ainsn.insn, p->addr, 0); - - if (can_boost(p->addr)) + if (can_boost(p->ainsn.insn)) p->ainsn.boostable = 0; else p->ainsn.boostable = -1; - p->opcode = *p->addr; + /* Also, displacement change doesn't affect the first byte */ + p->opcode = p->ainsn.insn[0]; } int __kprobes arch_prepare_kprobe(struct kprobe *p) @@ -1276,7 +1274,7 @@ static int __kprobes copy_optimized_instructions(u8 *dest, u8 *src) int len = 0, ret; while (len < RELATIVEJUMP_SIZE) { - ret = __copy_instruction(dest + len, src + len, 1); + ret = __copy_instruction(dest + len, src + len); if (!ret || !can_boost(dest + len)) return -EINVAL; len += ret; @@ -1328,7 +1326,7 @@ static int insn_jump_into_range(struct insn *insn, unsigned long start, int len) /* Decode whole function to ensure any instructions don't jump into target */ static int __kprobes can_optimize(unsigned long paddr) { - unsigned long addr, __addr, size = 0, offset = 0; + unsigned long addr, size = 0, offset = 0; struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; @@ -1357,8 +1355,7 @@ static int __kprobes can_optimize(unsigned long paddr) * we can't optimize kprobe in this function. */ return 0; - __addr = recover_probed_instruction(buf, addr); - kernel_insn_init(&insn, (void *)__addr); + kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, addr)); insn_get_length(&insn); /* Another subsystem puts a breakpoint */ if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) |