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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 1E000C433E0 for ; Fri, 15 Jan 2021 18:00:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BAF522339E for ; Fri, 15 Jan 2021 18:00:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BAF522339E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0558B8D01C7; Fri, 15 Jan 2021 13:00:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 02B148D01B2; Fri, 15 Jan 2021 13:00:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E853A8D01C7; Fri, 15 Jan 2021 13:00:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0154.hostedemail.com [216.40.44.154]) by kanga.kvack.org (Postfix) with ESMTP id D2B6F8D01B2 for ; Fri, 15 Jan 2021 13:00:09 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 9B26DDDFD for ; Fri, 15 Jan 2021 18:00:09 +0000 (UTC) X-FDA: 77708773338.30.bun19_3a1312a27531 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 6673D18158223 for ; Fri, 15 Jan 2021 18:00:09 +0000 (UTC) X-HE-Tag: bun19_3a1312a27531 X-Filterd-Recvd-Size: 3624 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 Jan 2021 18:00:07 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B0CC1ED1; Fri, 15 Jan 2021 10:00:06 -0800 (PST) Received: from [10.37.8.30] (unknown [10.37.8.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F33C03F719; Fri, 15 Jan 2021 10:00:02 -0800 (PST) Subject: Re: [PATCH v3 2/2] kasan, arm64: fix pointer tags in KASAN reports To: Andrey Konovalov , Andrew Morton , Catalin Marinas , Dmitry Vyukov , Alexander Potapenko , Marco Elver Cc: Will Deacon , Andrey Ryabinin , Peter Collingbourne , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: From: Vincenzo Frascino Message-ID: <2dfd9776-4b8f-45f8-b673-ecb7fa6e16be@arm.com> Date: Fri, 15 Jan 2021 18:03:49 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/15/21 5:41 PM, Andrey Konovalov wrote: > As of the "arm64: expose FAR_EL1 tag bits in siginfo" patch, the address > that is passed to report_tag_fault has pointer tags in the format of 0x0X, > while KASAN uses 0xFX format (note the difference in the top 4 bits). > > Fix up the pointer tag for kernel pointers in do_tag_check_fault by > setting them to the same value as bit 55. Explicitly use __untagged_addr() > instead of untagged_addr(), as the latter doesn't affect TTBR1 addresses. > > Link: https://linux-review.googlesource.com/id/I9ced973866036d8679e8f4ae325de547eb969649 > Fixes: dceec3ff7807 ("arm64: expose FAR_EL1 tag bits in siginfo") > Fixes: 4291e9ee6189 ("kasan, arm64: print report from tag fault handler") > Signed-off-by: Andrey Konovalov Reviewed-by: Vincenzo Frascino > --- > arch/arm64/mm/fault.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 3c40da479899..35d75c60e2b8 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -709,10 +709,11 @@ static int do_tag_check_fault(unsigned long far, unsigned int esr, > struct pt_regs *regs) > { > /* > - * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN for tag > - * check faults. Mask them out now so that userspace doesn't see them. > + * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN > + * for tag check faults. Set them to corresponding bits in the untagged > + * address. > */ > - far &= (1UL << 60) - 1; > + far = (__untagged_addr(far) & ~MTE_TAG_MASK) | (far & MTE_TAG_MASK); > do_bad_area(far, esr, regs); > return 0; > } > -- Regards, Vincenzo