From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753236AbdDLHkZ (ORCPT ); Wed, 12 Apr 2017 03:40:25 -0400 Received: from terminus.zytor.com ([65.50.211.136]:54571 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751020AbdDLHkX (ORCPT ); Wed, 12 Apr 2017 03:40:23 -0400 Date: Wed, 12 Apr 2017 00:34:35 -0700 From: tip-bot for Masami Hiramatsu Message-ID: Cc: hpa@zytor.com, tglx@linutronix.de, peterz@infradead.org, torvalds@linux-foundation.org, jpoimboe@redhat.com, brgerst@gmail.com, ananth@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, dvlasenk@redhat.com, xiaolong.ye@intel.com, mhiramat@kernel.org, mingo@kernel.org, bp@alien8.de, anil.s.keshavamurthy@intel.com, davem@davemloft.net, aryabinin@virtuozzo.com Reply-To: bp@alien8.de, anil.s.keshavamurthy@intel.com, aryabinin@virtuozzo.com, davem@davemloft.net, mingo@kernel.org, mhiramat@kernel.org, xiaolong.ye@intel.com, jpoimboe@redhat.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, dvlasenk@redhat.com, brgerst@gmail.com, ananth@linux.vnet.ibm.com, hpa@zytor.com, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <149076375592.22469.14174394514338612247.stgit@devbox> References: <149076375592.22469.14174394514338612247.stgit@devbox> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] kprobes/x86: Set kprobes pages read-only Git-Commit-ID: d0381c81c2f782fa2131178d11e0cfb23d50d631 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d0381c81c2f782fa2131178d11e0cfb23d50d631 Gitweb: http://git.kernel.org/tip/d0381c81c2f782fa2131178d11e0cfb23d50d631 Author: Masami Hiramatsu AuthorDate: Wed, 29 Mar 2017 14:02:46 +0900 Committer: Ingo Molnar CommitDate: Wed, 12 Apr 2017 09:23:46 +0200 kprobes/x86: Set kprobes pages read-only Set the pages which is used for kprobes' singlestep buffer and optprobe's trampoline instruction buffer to readonly. This can prevent unexpected (or unintended) instruction modification. This also passes rodata_test as below. Without this patch, rodata_test shows a warning: WARNING: CPU: 0 PID: 1 at arch/x86/mm/dump_pagetables.c:235 note_page+0x7a9/0xa20 x86/mm: Found insecure W+X mapping at address ffffffffa0000000/0xffffffffa0000000 With this fix, no W+X pages are found: x86/mm: Checked W+X mappings: passed, no W+X pages found. rodata_test: all tests were successful Reported-by: Andrey Ryabinin Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: Borislav Petkov Cc: Brian Gerst Cc: David S . Miller Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ye Xiaolong Link: http://lkml.kernel.org/r/149076375592.22469.14174394514338612247.stgit@devbox Signed-off-by: Ingo Molnar --- arch/x86/kernel/kprobes/core.c | 4 ++++ arch/x86/kernel/kprobes/opt.c | 3 +++ 2 files changed, 7 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 3f084a0..0dc24e6 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -419,6 +419,8 @@ static int arch_copy_kprobe(struct kprobe *p) { int len; + set_memory_rw((unsigned long)p->ainsn.insn & PAGE_MASK, 1); + /* Copy an instruction with recovering if other optprobe modifies it.*/ len = __copy_instruction(p->ainsn.insn, p->addr); if (!len) @@ -430,6 +432,8 @@ static int arch_copy_kprobe(struct kprobe *p) */ prepare_boost(p, len); + set_memory_ro((unsigned long)p->ainsn.insn & PAGE_MASK, 1); + /* Check whether the instruction modifies Interrupt Flag or not */ p->ainsn.if_modifier = is_IF_modifier(p->ainsn.insn); diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 3e7c6e5..b121037 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -350,6 +350,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, } buf = (u8 *)op->optinsn.insn; + set_memory_rw((unsigned long)buf & PAGE_MASK, 1); /* Copy instructions into the out-of-line buffer */ ret = copy_optimized_instructions(buf + TMPL_END_IDX, op->kp.addr); @@ -372,6 +373,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, synthesize_reljump(buf + TMPL_END_IDX + op->optinsn.size, (u8 *)op->kp.addr + op->optinsn.size); + set_memory_ro((unsigned long)buf & PAGE_MASK, 1); + flush_icache_range((unsigned long) buf, (unsigned long) buf + TMPL_END_IDX + op->optinsn.size + RELATIVEJUMP_SIZE);