From patchwork Mon Dec 20 22:01:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12688731 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0484C433EF for ; Mon, 20 Dec 2021 22:01:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 29B516B00A9; Mon, 20 Dec 2021 17:01:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2481F6B00AA; Mon, 20 Dec 2021 17:01:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 111B96B00AB; Mon, 20 Dec 2021 17:01:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0129.hostedemail.com [216.40.44.129]) by kanga.kvack.org (Postfix) with ESMTP id 016566B00A9 for ; Mon, 20 Dec 2021 17:01:24 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BB360181AC9C6 for ; Mon, 20 Dec 2021 22:01:24 +0000 (UTC) X-FDA: 78939544488.23.8E3D9B0 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf20.hostedemail.com (Postfix) with ESMTP id 143091C004C for ; Mon, 20 Dec 2021 22:01:18 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1640037682; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=T+YMJBAzt/nU23GNh+s+gTj6PS6iuM5TpfUBadGWu7U=; b=psD3KeETHzZFIJrpDJtfOFevgoBjn5PI9GxnLeJU5pttMh0GDW+WJTDXj7p5cn+v44mRTt zmr3npDBM4SoVYRPOMbw8XenIl92rjpcDzbiWRBJh6UK/2jS2J1DBhByuL2x0m7V7PCPrw 57WZxOYB+qqPjrdU/N9CQxil0stSuzY= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Andrew Morton Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino , Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Peter Collingbourne , Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm v4 22/39] kasan, fork: reset pointer tags of vmapped stacks Date: Mon, 20 Dec 2021 23:01:01 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 143091C004C X-Stat-Signature: kan3zorfkh1eruuecgjh1ccogip39eas Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=psD3KeET; spf=pass (imf20.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-HE-Tag: 1640037678-673659 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: From: Andrey Konovalov Once tag-based KASAN modes start tagging vmalloc() allocations, kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled. Reset the tag of kernel stack pointers after allocation in alloc_thread_stack_node(). For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the instrumentation can't handle the SP register being tagged. For HW_TAGS KASAN, there's no instrumentation-related issues. However, the impact of having a tagged SP register needs to be properly evaluated, so keep it non-tagged for now. Note, that the memory for the stack allocation still gets tagged to catch vmalloc-into-stack out-of-bounds accesses. Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- Changes v2->v3: - Update patch description. --- kernel/fork.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/fork.c b/kernel/fork.c index 403b9dbbfb62..4125373dba4e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -254,6 +254,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) * so cache the vm_struct. */ if (stack) { + stack = kasan_reset_tag(stack); tsk->stack_vm_area = find_vm_area(stack); tsk->stack = stack; }