From patchwork Tue Feb 27 01:35:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zev Weiss X-Patchwork-Id: 1904811 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.a=rsa-sha256 header.s=thorn header.b=AxLlMvyX; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=openbmc-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=patchwork.ozlabs.org) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TkKnt3BhHz23cx for ; Tue, 27 Feb 2024 12:36:18 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.a=rsa-sha256 header.s=thorn header.b=AxLlMvyX; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4TkKns4zHxz3d23 for ; Tue, 27 Feb 2024 12:36:17 +1100 (AEDT) X-Original-To: openbmc@lists.ozlabs.org Delivered-To: openbmc@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.a=rsa-sha256 header.s=thorn header.b=AxLlMvyX; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=bewilderbeest.net (client-ip=71.19.156.171; helo=thorn.bewilderbeest.net; envelope-from=zev@bewilderbeest.net; receiver=lists.ozlabs.org) Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [71.19.156.171]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4TkKnT0RG5z3by2 for ; Tue, 27 Feb 2024 12:35:56 +1100 (AEDT) Received: from hatter.bewilderbeest.net (unknown [IPv6:2602:61:712b:6300::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id BAB8642BE; Mon, 26 Feb 2024 17:35:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1708997755; bh=djflHMn74Aoza7I3oyPhQDEGULANvQSmtPsfFrwIYIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AxLlMvyXHvt14ldDBhIa4S0wWMk7ibuO9rV2OF7ak9xXdpCJTaFgDzP64nK/sv6Gm Fowrni/G+U1w2BihQcqwfrtfhR1BA4Cl1XVSXbu659qFAh+yQDK1nNCqPM1hssMDdE bWpi/y082Tr2j+A0xZ8/9iE6fD6FJJPTY1hpF18o= From: Zev Weiss To: Russell King , linux-parisc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Helge Deller , Florent Revest Subject: [PATCH RESEND 1/2] prctl: Generalize PR_SET_MDWE support check to be per-arch Date: Mon, 26 Feb 2024 17:35:41 -0800 Message-ID: <20240227013546.15769-5-zev@bewilderbeest.net> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240227013546.15769-4-zev@bewilderbeest.net> References: <20240227013546.15769-4-zev@bewilderbeest.net> MIME-Version: 1.0 X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sam James , Ondrej Mosnacek , Kees Cook , Zev Weiss , David Hildenbrand , linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org, Stefan Roesch , Yin Fengwei , stable@vger.kernel.org, Oleg Nesterov , "James E.J. Bottomley" , "Borislav Petkov \(AMD\)" , Yang Shi , Miguel Ojeda , Andrew Morton , Rick Edgecombe , "Mike Rapoport \(IBM\)" , Josh Triplett Errors-To: openbmc-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "openbmc" There exist systems other than PARISC where MDWE may not be feasible to support; rather than cluttering up the generic code with additional arch-specific logic let's add a generic function for checking MDWE support and allow each arch to override it as needed. Signed-off-by: Zev Weiss Cc: # v6.3+ Acked-by: Helge Deller # parisc --- arch/parisc/include/asm/mman.h | 14 ++++++++++++++ include/linux/mman.h | 8 ++++++++ kernel/sys.c | 7 +++++-- 3 files changed, 27 insertions(+), 2 deletions(-) create mode 100644 arch/parisc/include/asm/mman.h diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h new file mode 100644 index 000000000000..47c5a1991d10 --- /dev/null +++ b/arch/parisc/include/asm/mman.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include + +/* PARISC cannot allow mdwe as it needs writable stacks */ +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return false; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported + +#endif /* __ASM_MMAN_H__ */ diff --git a/include/linux/mman.h b/include/linux/mman.h index dc7048824be8..bcb201ab7a41 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -162,6 +162,14 @@ calc_vm_flag_bits(unsigned long flags) unsigned long vm_commit_limit(void); +#ifndef arch_memory_deny_write_exec_supported +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return true; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported +#endif + /* * Denies creating a writable executable mapping or gaining executable permissions. * diff --git a/kernel/sys.c b/kernel/sys.c index f8e543f1e38a..8bb106a56b3a 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2408,8 +2408,11 @@ static inline int prctl_set_mdwe(unsigned long bits, unsigned long arg3, if (bits & PR_MDWE_NO_INHERIT && !(bits & PR_MDWE_REFUSE_EXEC_GAIN)) return -EINVAL; - /* PARISC cannot allow mdwe as it needs writable stacks */ - if (IS_ENABLED(CONFIG_PARISC)) + /* + * EOPNOTSUPP might be more appropriate here in principle, but + * existing userspace depends on EINVAL specifically. + */ + if (!arch_memory_deny_write_exec_supported()) return -EINVAL; current_bits = get_current_mdwe();