From patchwork Tue Jan 19 17:26:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincenzo Frascino X-Patchwork-Id: 12030953 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=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 A6F21C433E0 for ; Tue, 19 Jan 2021 22:20:29 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5192022E01 for ; Tue, 19 Jan 2021 22:20:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5192022E01 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=DRCN2TD9UWVT3myyv7XQ3JXGY3kfwVXf6FkVaVC9udM=; b=eGkVQfhDOXQRZA6cqxkPCSousx qqHrpk4e0Yx8aJydrYSVNVX9yzzQZmQJGg2PgfO+tg+aRQR6pz01vvdt0VN00hCWmVIUleuyMPe5e B7ATVxAXumW8KVyZ7np+5L/luFcu3nVT6eJC2TLhcoga+A1af8TmG04iGiO7Ef09fKNYsGFGo+/M3 +o7wb6ytLKIm5CijdTmQ00dA3HQ6LsKRTdLx09uAGCvj+O0846n1KqObHzakdIvs4IUH+NEqJniLF h2ltub6bIu9tLynrC03G+bZHjP3qoTiWODwloO+iAuVimcd6cOrV/V/SKR9TMJ4pPnWCI5cNveR8k yULGVOkA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l1ulu-0008Cd-EP; Tue, 19 Jan 2021 17:26:26 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l1uls-0008CF-DY for linux-arm-kernel@lists.infradead.org; Tue, 19 Jan 2021 17:26:25 +0000 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 AB5781396; Tue, 19 Jan 2021 09:26:21 -0800 (PST) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7594C3F66E; Tue, 19 Jan 2021 09:26:20 -0800 (PST) From: Vincenzo Frascino To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH] kasan: Add explicit preconditions to kasan_report() Date: Tue, 19 Jan 2021 17:26:07 +0000 Message-Id: <20210119172607.18400-1-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210119_122624_500644_E762F72D X-CRM114-Status: GOOD ( 13.54 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrey Konovalov , Leon Romanovsky , Alexander Potapenko , Andrey Ryabinin , Vincenzo Frascino , Dmitry Vyukov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org With the introduction of KASAN_HW_TAGS, kasan_report() dereferences the address passed as a parameter. Add a comment to make sure that the preconditions to the function are explicitly clarified. Note: An invalid address (e.g. NULL pointer address) passed to the function when, KASAN_HW_TAGS is enabled, leads to a kernel panic. Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Leon Romanovsky Cc: Andrey Konovalov Signed-off-by: Vincenzo Frascino --- mm/kasan/report.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index c0fb21797550..2485b585004d 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -403,6 +403,17 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write, end_report(&flags); } +/** + * kasan_report - report kasan fault details + * @addr: valid address of the allocation where the tag fault was detected + * @size: size of the allocation where the tag fault was detected + * @is_write: the instruction that caused the fault was a read or write? + * @ip: pointer to the instruction that cause the fault + * + * Note: When CONFIG_KASAN_HW_TAGS is enabled kasan_report() dereferences + * the address to access the tags, hence it must be valid at this point in + * order to not cause a kernel panic. + */ bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) {