From patchwork Mon Jan 24 18:04:56 2022 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: 12722674 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 B36A5C433EF for ; Mon, 24 Jan 2022 18:05:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0F6A76B00AB; Mon, 24 Jan 2022 13:05:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 02EDA6B00B7; Mon, 24 Jan 2022 13:05:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E112E6B00B9; Mon, 24 Jan 2022 13:05:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0144.hostedemail.com [216.40.44.144]) by kanga.kvack.org (Postfix) with ESMTP id D20676B00AB for ; Mon, 24 Jan 2022 13:05:21 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 924C89366C for ; Mon, 24 Jan 2022 18:05:21 +0000 (UTC) X-FDA: 79065957642.16.8200F6F Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by imf26.hostedemail.com (Postfix) with ESMTP id 268631400B6 for ; Mon, 24 Jan 2022 18:05:21 +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=1643047519; 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=/XjTstEAGTMnS2cfhATsR9x5w6K0TN8X9h4vHjvkVrw=; b=IyNV3VAB/t0xjLzGOgv309VybgWXRFeywRGdKZZV4iWmY3e4kmKdNicqqTqZ0zN6pNo8pb Dz0IPusOEJkjC1XcK7aZ0CY5vehv5/xzm45oSN0+WTwFS1+6OxePIrkEnh8zjQNUZ/2XdF maXcYOD2z9VsCMIHn0R0EO1mtu8+Iuw= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , 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 v6 22/39] kasan, fork: reset pointer tags of vmapped stacks Date: Mon, 24 Jan 2022 19:04:56 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Stat-Signature: iuyfcor15a91t1kkb41syxpc55xprbyn Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=IyNV3VAB; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf26.hostedemail.com: domain of andrey.konovalov@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 268631400B6 X-HE-Tag: 1643047521-687136 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 d75a528f7b21..57d624f05182 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; }