From patchwork Tue Nov 30 22:07:06 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: 12694240 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E05F5C433F5 for ; Tue, 30 Nov 2021 22:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1sCxx1yBjLq+1Z/DTzVuzYfudyzk72l59sAFekNH2mw=; b=cVSA8ybFNcC/eX dd/VF4WFYVYDwdGeckXiIj2nmVENkpiyycd1VXAse/350lUW3eERzbE/zV62/aaYwNfRVloWQ6T5h a1/YLYAk5D0PvhP+FBnUuoFREQ/s14BxkjLttcQaIUWJ3iLawEUN/1PHAem8+1OLWTuE+/BPA8dOF swEwvwZGDdK4btb1aOLHuBP2icAYwpirRrk5pWFbeUCwmY1iClB+y17Af6myfy+cyhrspAVi3cadf 2SGklK+47tgSNvIVWO1FQCJPpjp1jjRPHE3PJbm6xtnBQGIauVsBiILy9OWr4L157EXWXBpYskuLi gFdSWpebK4DNJ/zDyc+w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1msBR2-006yAB-2d; Tue, 30 Nov 2021 22:17:12 +0000 Received: from out2.migadu.com ([2001:41d0:2:aacc::]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1msBHb-006uWf-Lo for linux-arm-kernel@lists.infradead.org; Tue, 30 Nov 2021 22:07:29 +0000 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=1638310046; 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=nHVI23+3UF63ZVUN3WDdsPua2nJbVrQ0CU8a80/ebmM=; b=MCS0gr3NKMKS+MZEDBaMQ/Y9/5T2w+73B9TItzWtMLefE5EHaRFQzM5uTk5JfSbcjlNsNJ clajPruoCBBKoh6krQX41cV6f6kN/CtouTlw3ANqaim6nJgYMDiSqNJmJc1rexKdSdbIJR qeJI3c5rDVpGngDokWTORCYaTKR8P7E= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH 21/31] kasan, fork: don't tag stacks allocated with vmalloc Date: Tue, 30 Nov 2021 23:07:06 +0100 Message-Id: <4fbc6668845e699bf708aee5c11ad9fd012d4dcd.1638308023.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211130_140727_903233_863D01ED X-CRM114-Status: GOOD ( 10.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Andrey Konovalov Once tag-based KASAN modes start tagging vmalloc() allocations, kernel stacks will start getting tagged if CONFIG_VMAP_STACK is enabled. Reset the tag of kernel stack pointers after allocation. 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 pointer 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 --- kernel/fork.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/fork.c b/kernel/fork.c index 3244cc56b697..062d1484ef42 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -253,6 +253,7 @@ 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; }