From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 511A4C5CFEB for ; Mon, 9 Jul 2018 19:52:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0B7E208A2 for ; Mon, 9 Jul 2018 19:52:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="J8MZshJ1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0B7E208A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=efficios.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933268AbeGITwL (ORCPT ); Mon, 9 Jul 2018 15:52:11 -0400 Received: from mail.efficios.com ([167.114.142.138]:59904 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932879AbeGITwC (ORCPT ); Mon, 9 Jul 2018 15:52:02 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 7A68023260C; Mon, 9 Jul 2018 15:52:01 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id XNAaRZbMweTL; Mon, 9 Jul 2018 15:52:01 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id EEBD22325FE; Mon, 9 Jul 2018 15:52:00 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com EEBD22325FE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1531165921; bh=WZv917Woasf838aPBnaMB+JF/a2sr2veP7Gf+ck0+uc=; h=From:To:Date:Message-Id; b=J8MZshJ1xw4D8YYw7pifuUSqMvlfg+O6SWHVkBZiK/dxFbzBGyvRjpzYb4pbKIa0K xpE1O8BYZj8qhsUJGqDUFIMNzIRM35+uG8t6wHJRC9z09E2szQlK8zD5pyYUNZPoYk B+QRSNyuhX1RSnDDF1afaSWKi/aVMp1AQJxiqWMXpONDxhJbELYdJMQOmGTjpIxgAM MqatWAVHFyf4Y5hCG/+zLVbG4Nlfaw8nDBYqce0QFycWZkNeoc/XZI39creVGnVgzT BCxpY3PSa7OvUa6rOyXg94HScCjQ9Rwn6/UyRUvZmbLJ1OIx+B+CjORpmSzym8/6+2 VCvJ+jN+/jGLg== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id 6oWwjzgXdM89; Mon, 9 Jul 2018 15:52:00 -0400 (EDT) Received: from thinkos.internal.efficios.com (192-222-157-41.qc.cable.ebox.net [192.222.157.41]) by mail.efficios.com (Postfix) with ESMTPSA id 964792325EB; Mon, 9 Jul 2018 15:52:00 -0400 (EDT) From: Mathieu Desnoyers To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Peter Zijlstra , "Paul E . McKenney" , Boqun Feng , Andy Lutomirski , Dave Watson , Paul Turner , Andrew Morton , Russell King , Ingo Molnar , "H . Peter Anvin" , Andi Kleen , Chris Lameter , Ben Maurer , Steven Rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will Deacon , Michael Kerrisk , Joel Fernandes , Mathieu Desnoyers Subject: [PATCH for 4.18 4/6] rseq: uapi: declare rseq_cs field as union, update includes Date: Mon, 9 Jul 2018 15:51:53 -0400 Message-Id: <20180709195155.7654-5-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180709195155.7654-1-mathieu.desnoyers@efficios.com> References: <20180709195155.7654-1-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Declaring the rseq_cs field as a union between __u64 and two __u32 allows both 32-bit and 64-bit kernels to read the full __u64, and therefore validate that a 32-bit user-space cleared the upper 32 bits, thus ensuring a consistent behavior between native 32-bit kernels and 32-bit compat tasks on 64-bit kernels. Check that the rseq_cs value read is < TASK_SIZE. The asm/byteorder.h header needs to be included by rseq.h, now that it is not using linux/types_32_64.h anymore. Considering that only __32 and __u64 types are declared in linux/rseq.h, the linux/types.h header should always be included for both kernel and user-space code: including stdint.h is just for u64 and u32, which are not used in this header at all. Use copy_from_user()/clear_user() to interact with a 64-bit field, because arm32 does not implement 64-bit __get_user, and ppc32 does not 64-bit get_user. Considering that the rseq_cs pointer does not need to be loaded/stored with single-copy atomicity from the kernel anymore, we can simply use copy_from_user()/clear_user(). Signed-off-by: Mathieu Desnoyers CC: "Paul E. McKenney" CC: Peter Zijlstra CC: Paul Turner CC: Thomas Gleixner CC: Andy Lutomirski CC: Andi Kleen CC: Dave Watson CC: Chris Lameter CC: Ingo Molnar CC: "H. Peter Anvin" CC: Ben Maurer CC: Steven Rostedt CC: Josh Triplett CC: Linus Torvalds CC: Andrew Morton CC: Russell King CC: Catalin Marinas CC: Will Deacon CC: Michael Kerrisk CC: Boqun Feng CC: linux-api@vger.kernel.org --- include/uapi/linux/rseq.h | 27 +++++++++++++++++++-------- kernel/rseq.c | 15 +++++++++------ tools/testing/selftests/rseq/rseq.h | 11 ++++++++++- 3 files changed, 38 insertions(+), 15 deletions(-) diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index bf4188c13bec..9a402fdb60e9 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -10,13 +10,8 @@ * Copyright (c) 2015-2018 Mathieu Desnoyers */ -#ifdef __KERNEL__ -# include -#else -# include -#endif - -#include +#include +#include enum rseq_cpu_id_state { RSEQ_CPU_ID_UNINITIALIZED = -1, @@ -111,7 +106,23 @@ struct rseq { * atomicity semantics. This field should only be updated by the * thread which registered this data structure. Aligned on 64-bit. */ - LINUX_FIELD_u32_u64(rseq_cs); + union { + __u64 ptr64; +#ifdef __LP64__ + __u64 ptr; +#else + struct { +#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN) + __u32 padding; /* Initialized to zero. */ + __u32 ptr32; +#else /* LITTLE */ + __u32 ptr32; + __u32 padding; /* Initialized to zero. */ +#endif /* ENDIAN */ + } ptr; +#endif + } rseq_cs; + /* * Restartable sequences flags field. * diff --git a/kernel/rseq.c b/kernel/rseq.c index 2a7748675be7..c6242d8594dc 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -115,19 +115,20 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t) static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs) { struct rseq_cs __user *urseq_cs; - unsigned long ptr; + u64 ptr; u32 __user *usig; u32 sig; int ret; - ret = get_user(ptr, &t->rseq->rseq_cs); - if (ret) - return ret; + if (copy_from_user(&ptr, &t->rseq->rseq_cs.ptr64, sizeof(ptr))) + return -EFAULT; if (!ptr) { memset(rseq_cs, 0, sizeof(*rseq_cs)); return 0; } - urseq_cs = (struct rseq_cs __user *)ptr; + if (ptr >= TASK_SIZE) + return -EINVAL; + urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr; if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs))) return -EFAULT; @@ -203,7 +204,9 @@ static int clear_rseq_cs(struct task_struct *t) * * Set rseq_cs to NULL. */ - return put_user(0UL, &t->rseq->rseq_cs); + if (clear_user(&t->rseq->rseq_cs.ptr64, sizeof(t->rseq->rseq_cs.ptr64))) + return -EFAULT; + return 0; } /* diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h index a4684112676c..f2073cfa4448 100644 --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -133,6 +133,15 @@ static inline uint32_t rseq_current_cpu(void) return cpu; } +static inline void rseq_clear_rseq_cs(void) +{ +#ifdef __LP64__ + __rseq_abi.rseq_cs.ptr = 0; +#else + __rseq_abi.rseq_cs.ptr.ptr32 = 0; +#endif +} + /* * rseq_prepare_unload() should be invoked by each thread using rseq_finish*() * at least once between their last rseq_finish*() and library unload of the @@ -143,7 +152,7 @@ static inline uint32_t rseq_current_cpu(void) */ static inline void rseq_prepare_unload(void) { - __rseq_abi.rseq_cs = 0; + rseq_clear_rseq_cs(); } #endif /* RSEQ_H_ */ -- 2.11.0