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: 13573087 Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [71.19.156.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EADF53A7; Tue, 27 Feb 2024 01:35:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=71.19.156.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708997757; cv=none; b=BBd6brvpNXgobFymLQhG/dF4YcvgHaL2tpZP3ihWqJYzjYH3vgHiunkkChq9Sd2K1LKIk5SOCbRoc5UItKjR+1Ivxzglb+f5iDoIrGJxmVBVVnc0yjL1fl/6iy6iLTfavduDb2d4NohMI8BHiFPZaZBo9s80LpljsHm+GR5qWpA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708997757; c=relaxed/simple; bh=cskhCraRLUN/8AG+y2v+YigFt0ecsFqLjy2QTRPHqrE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dvEP0PRnTBtXYUFXuk2i4YYa+7hQclkO1v0HC9N90V4+K8JssQ1Q5Cgn77kTv9+8ZIiT89ghwFoS37+FWxklBTRyawh2tlSBPr/sp3H48XbVYthOnt9NtnKwtDXznUpGYrakUxSaANFvbbT/7hZdzPKhm7pPWO3PqSSAeo28jvc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net; spf=pass smtp.mailfrom=bewilderbeest.net; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b=AxLlMvyX; arc=none smtp.client-ip=71.19.156.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b="AxLlMvyX" 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 Cc: Zev Weiss , "James E.J. Bottomley" , "Borislav Petkov (AMD)" , Yin Fengwei , "Mike Rapoport (IBM)" , Andrew Morton , Kees Cook , Yang Shi , Rick Edgecombe , Oleg Nesterov , David Hildenbrand , Stefan Roesch , Josh Triplett , Ondrej Mosnacek , Miguel Ojeda , linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org, Sam James , stable@vger.kernel.org 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> Precedence: bulk X-Mailing-List: linux-parisc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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();