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=-19.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 83C5DC4332E for ; Mon, 8 Feb 2021 18:06:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 415BA64DE1 for ; Mon, 8 Feb 2021 18:06:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235419AbhBHSFx (ORCPT ); Mon, 8 Feb 2021 13:05:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:46604 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232048AbhBHSCD (ORCPT ); Mon, 8 Feb 2021 13:02:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 27D6464ECE; Mon, 8 Feb 2021 17:58:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612807132; bh=iNhBaqcKo5xlqkXO9BkzW2PKLCoLecJSEpmH4XRm8xQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BK8mZc5uWDjTF8CsFBZ0ym1DEx0/UDbr4g6i+Kz8xswsfHo1C5K5IFfVAF5S1IYv2 dnr+P9lXH/KI4U5T9AM/Mkx65uQMIQf0xzN2tMDhBjgBNTNuOGyE+daEmHFT6F289o NgikidP9O7Sn7cbiFZTu9ABA7U47okLwa97CeWvGK7lUA4ZZf0GnDnd39SdhUNXxcn 4OPK05wCQ9bkwAGLZ79qynXpWjnegAEQnF0mXIUBEnuze0dfEWXqoZiBdAmw2iNrSw DmjXawiHdgk1AWxU5xR9XSOnF1TK1HKCsH6yriwSY2dHu4u+e6jAg8b9HhyjXwcezc GpKl3Z8Z0aUvA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vincenzo Frascino , Andrey Konovalov , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Leon Romanovsky , Catalin Marinas , Will Deacon , Mark Rutland , "Paul E . McKenney" , Naresh Kamboju , Andrew Morton , Linus Torvalds , Sasha Levin , kasan-dev@googlegroups.com Subject: [PATCH AUTOSEL 5.10 33/36] kasan: add explicit preconditions to kasan_report() Date: Mon, 8 Feb 2021 12:58:03 -0500 Message-Id: <20210208175806.2091668-33-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210208175806.2091668-1-sashal@kernel.org> References: <20210208175806.2091668-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vincenzo Frascino [ Upstream commit 49c6631d3b4f61a7b5bb0453a885a12bfa06ffd8 ] Patch series "kasan: Fix metadata detection for KASAN_HW_TAGS", v5. With the introduction of KASAN_HW_TAGS, kasan_report() currently assumes that every location in memory has valid metadata associated. This is due to the fact that addr_has_metadata() returns always true. As a consequence of this, an invalid address (e.g. NULL pointer address) passed to kasan_report() when KASAN_HW_TAGS is enabled, leads to a kernel panic. Example below, based on arm64: BUG: KASAN: invalid-access in 0x0 Read at addr 0000000000000000 by task swapper/0/1 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x96000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 ... Call trace: mte_get_mem_tag+0x24/0x40 kasan_report+0x1a4/0x410 alsa_sound_last_init+0x8c/0xa4 do_one_initcall+0x50/0x1b0 kernel_init_freeable+0x1d4/0x23c kernel_init+0x14/0x118 ret_from_fork+0x10/0x34 Code: d65f03c0 9000f021 f9428021 b6cfff61 (d9600000) ---[ end trace 377c8bb45bdd3a1a ]--- hrtimer: interrupt took 48694256 ns note: swapper/0[1] exited with preempt_count 1 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b SMP: stopping secondary CPUs Kernel Offset: 0x35abaf140000 from 0xffff800010000000 PHYS_OFFSET: 0x40000000 CPU features: 0x0a7e0152,61c0a030 Memory Limit: none ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- This series fixes the behavior of addr_has_metadata() that now returns true only when the address is valid. This patch (of 2): With the introduction of KASAN_HW_TAGS, kasan_report() accesses the metadata only when addr_has_metadata() succeeds. Add a comment to make sure that the preconditions to the function are explicitly clarified. Link: https://lkml.kernel.org/r/20210126134409.47894-1-vincenzo.frascino@arm.com Link: https://lkml.kernel.org/r/20210126134409.47894-2-vincenzo.frascino@arm.com Signed-off-by: Vincenzo Frascino Reviewed-by: Andrey Konovalov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Leon Romanovsky Cc: Andrey Konovalov Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: "Paul E . McKenney" Cc: Naresh Kamboju Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- include/linux/kasan.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 30d343b4a40a5..646fa165d2cce 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -196,6 +196,13 @@ void kasan_init_tags(void); void *kasan_reset_tag(const void *addr); +/** + * kasan_report - print a report about a bad memory access detected by KASAN + * @addr: address of the bad access + * @size: size of the bad access + * @is_write: whether the bad access is a write or a read + * @ip: instruction pointer for the accessibility check or the bad access itself + */ bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip); -- 2.27.0