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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 BFCB0C433E7 for ; Thu, 15 Oct 2020 10:48:21 +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 381A622249 for ; Thu, 15 Oct 2020 10:48:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="x6gcT6Rq"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="QIkrJZh4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 381A622249 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NVf690HmOWZmhl9mFt03NZoW5FBlKMDHDt74p5N5Yrc=; b=x6gcT6RqLtpq9HNnW0emixZDn W1es10foXQMEdeT+FkzNjHgQVrGLWuNahdIs2zihBb4uc1na9738OVyp4JfOHd+7YdCQrEVRPOHic bRrIdx7D3G+lS7V6xi3yEhhz517sXAO6D34WBBw2YuvgpBkG+cUmFQUwKmuMiKALjFXNXvirDZysu 8KXWDrHbtAWKr5bkm2NzL/iTaJjam2vAViq+8UxUy0DHPf0YXCuqDbzGmi+dW24wV4orOxZ+OWwb7 HnMmxxQIHWS8wlxzjsSFcugbQ082CWp1rHj7xa9a384jNTPESHpfOCQifZpAe/zYrKijuNZBhgXzS OMWTfHoFw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kT0mg-0001zz-8X; Thu, 15 Oct 2020 10:46:58 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kT0md-0001yq-0V for linux-arm-kernel@lists.infradead.org; Thu, 15 Oct 2020 10:46:55 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E01D922249; Thu, 15 Oct 2020 10:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602758813; bh=wYp09EO6V7Zdjrz19kvaW98v4F5WxxX8tOI8s2rwT/E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QIkrJZh48ugrbdujbTlXrNKKuCDSH8alCbrh7D4E+/lZvi/nwTLmCe7W2PWPP1yY0 3i5JCkxzG40sd63lh1BBDVcyGWhyiaQdyqp7LVtX33NirTsHcpdmeWEP1cvZrWrl6W kDoXt5YfHkYZr3FMted/k3DOAPn/0gs52yNRXSyM= Date: Thu, 15 Oct 2020 11:46:48 +0100 From: Will Deacon To: Peter Collingbourne Subject: Re: [PATCH] arm64: reject prctl(PR_PAC_RESET_KEYS) on compat tasks Message-ID: <20201015104648.GB5064@willie-the-truck> References: <20201014052430.11630-1-pcc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201014052430.11630-1-pcc@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201015_064655_133407_D32B2A4D X-CRM114-Status: GOOD ( 22.26 ) 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: Linux ARM , Catalin Marinas , Vincenzo Frascino , Dave Martin , Kristina Martsenko Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Oct 13, 2020 at 10:24:30PM -0700, Peter Collingbourne wrote: > It doesn't make sense to issue prctl(PR_PAC_RESET_KEYS) on a > compat task because the 32-bit instruction set does not offer PAuth > instructions. For consistency with other 64-bit only prctls such as > {SET,GET}_TAGGED_ADDR_CTRL, reject the prctl on compat tasks. > > Although this is a userspace-visible change, maybe it isn't too late > to make this change given that the hardware isn't available yet and > it's very unlikely that anyone has 32-bit software that actually > depends on this succeeding. > > Link: https://linux-review.googlesource.com/id/Ie885a1ff84ab498cc9f62d6451e9f2cfd4b1d06a > Signed-off-by: Peter Collingbourne > --- > arch/arm64/kernel/pointer_auth.c | 4 ++++ > 1 file changed, 4 insertions(+) Cheers. Although I agree with the discussion here that it would be better to catch this in one place, for now I'll merge this and add similar checks to the SVE prctl()s too. Patch below (I also tweaked it to use the 'tsk' parameter for ptrauth, for consistency). Will --->8 diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index a6d688c10745..062b21f30f94 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -678,7 +678,7 @@ int sve_set_current_vl(unsigned long arg) vl = arg & PR_SVE_VL_LEN_MASK; flags = arg & ~vl; - if (!system_supports_sve()) + if (!system_supports_sve() || is_compat_task()) return -EINVAL; ret = sve_set_vector_length(current, vl, flags); @@ -691,7 +691,7 @@ int sve_set_current_vl(unsigned long arg) /* PR_SVE_GET_VL */ int sve_get_current_vl(void) { - if (!system_supports_sve()) + if (!system_supports_sve() || is_compat_task()) return -EINVAL; return sve_prctl_status(0); diff --git a/arch/arm64/kernel/pointer_auth.c b/arch/arm64/kernel/pointer_auth.c index 1e77736a4f66..adb955fd9bdd 100644 --- a/arch/arm64/kernel/pointer_auth.c +++ b/arch/arm64/kernel/pointer_auth.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 +#include #include #include #include @@ -17,6 +18,9 @@ int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg) if (!system_supports_address_auth() && !system_supports_generic_auth()) return -EINVAL; + if (is_compat_thread(task_thread_info(tsk))) + return -EINVAL; + if (!arg) { ptrauth_keys_init_user(keys); return 0; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel