linux-kernel - [RFC PATCH tip/master 0/8] kprobes/x86: Make kprobes instruction buffers read-only

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <149049860802.5373.14864980110354664466.stgit@devbox>
Date:   Sun, 26 Mar 2017 12:23:38 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
        "David S . Miller" <davem@...emloft.net>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>, mhiramat@...nel.org
Subject: [RFC PATCH tip/master 0/8] kprobes/x86: Make kprobes instruction buffers read-only

Hi,

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.

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.

---

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   |  143 +++++++++++++++++++-------------------
 arch/x86/kernel/kprobes/ftrace.c |    2 -
 arch/x86/kernel/kprobes/opt.c    |   13 +++
 5 files changed, 86 insertions(+), 83 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@...nel.org>