Messages in this thread | | | From | Masami Hiramatsu <> | Subject | [RFC PATCH tip/master V2 0/8] kprobes/x86: Make kprobes instruction buffers read-only | Date | Mon, 27 Mar 2017 16:48:46 +0900 |
| |
Hi,
This is the 2nd version of the series, which has been updated only 8/8, built and tested correctly. (Sorry, in previous version I missed to build and tested different kernel.)
This series tries to make kprobes instruction buffers read-only pages. Since those buffers are used for trampoline code, those are a part of "text area" and it should be marked as ro for avoiding unexpected modification. And this actually fix a warning rodata sanity check reported by lkp-robot.
https://lkml.org/lkml/2017/2/27/161
This change requires changing the kprobe-booster at first because it can modify the instruction buffer to add a jump while resuming from single-stepping. Of course after we make the buffer readonly, we may not be able to modify it while probing.
So, at first this series checks the current bootable instructions and fixes a missed instruction (call far), modifies can_boost to use x86 instruction decoder, and inserts "booster" jump while preparing instruction buffer instead of resuming from single-stepping. At last, it makes the buffers for kprobes and optprobe readonly.
This series also has some cleanup patches related to above changes.
Changes from V1: - [8/8]: Fix build errors.
---
Masami Hiramatsu (8): kprobes/x86: Fix not to boost call far instruction kprobes/x86: Fix the description of __copy_instruction() kprobes/x86: Use instruction decoder for booster kprobes/x86: Do not modify singlestep buffer while resuming kprobes/x86: Make boostable flag boolean kprobes/x86: Set kprobes pages readonly kprobes/x86: Use probe_kernel_read instead of memcpy kprobes/x86: Consolidate insn decoder users for copying code
arch/x86/include/asm/kprobes.h | 7 +- arch/x86/kernel/kprobes/common.h | 4 + arch/x86/kernel/kprobes/core.c | 148 +++++++++++++++++++------------------- arch/x86/kernel/kprobes/ftrace.c | 2 - arch/x86/kernel/kprobes/opt.c | 13 +++ 5 files changed, 89 insertions(+), 85 deletions(-)
-- Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
| |