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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v2-20020a17090a4ec200b00237a82e4f35si12707176pjl.126.2023.03.07.06.10.55; Tue, 07 Mar 2023 06:11:08 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b="PN/3C4zb"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229549AbjCGOJM (ORCPT + 99 others); Tue, 7 Mar 2023 09:09:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230490AbjCGOIT (ORCPT ); Tue, 7 Mar 2023 09:08:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B345D867D9 for ; Tue, 7 Mar 2023 06:07:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6F458B818E9 for ; Tue, 7 Mar 2023 14:07:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BFA7C433A0; Tue, 7 Mar 2023 14:07:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678198051; bh=hxezYyQWYIw+0PPMhQw20oQnBobe/ik8sJQ0xwbtFKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PN/3C4zb71kHR2EC4VJjtXnKKx1XE1/0BQIwxpmI4Sxj9+qp1VKbeKRhbtc3YAbeS C8nfCAr7iCCKwFTrN4Oh04FXik3kVT7LDN9uTZw0+Lk1OXgla25XwYfRCUcwluEryz /L5oexRVHy0Z9i2k868BgOZpWj/b2H/a82nB9wrH7nQMv/s1XjFi2u1QLr5aSPnfnQ +MASJV4gL5qSvvoYDl3yX9YX2CIRFZ7bKraUQhipCfIyJRyIAY6xWfykKoC7KlvYfS Itdtg0RwutZeNXFZsjZOf1ERf3ap3TCr0axn8gYhejqt8n+W569S/elox04drH9bCk 4WDOl8gatJ64w== From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Catalin Marinas , Will Deacon , Marc Zyngier , Mark Rutland , Ryan Roberts , Anshuman Khandual , Kees Cook Subject: [PATCH v3 22/60] arm64: idreg-override: Avoid kstrtou64() to parse a single hex digit Date: Tue, 7 Mar 2023 15:04:44 +0100 Message-Id: <20230307140522.2311461-23-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307140522.2311461-1-ardb@kernel.org> References: <20230307140522.2311461-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1644; i=ardb@kernel.org; h=from:subject; bh=hxezYyQWYIw+0PPMhQw20oQnBobe/ik8sJQ0xwbtFKk=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIYXdxXTJ4/+G+3m9lvhO8o42u3pI5v863Y/XyvXOtszzz 05/ukGio5SFQYyDQVZMkUVg9t93O09PlKp1niULM4eVCWQIAxenAEzknRvD/zxxTYk8/79ts88/ O2Muq6LueLq+zpBx629WkdAZvWJeYYwMbT/OVrn5yD+Ku7yh+e0MMb+Xx97qOCw7raRkftTqL4M tEwA= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759718427356214373?= X-GMAIL-MSGID: =?utf-8?q?1759718427356214373?= All ID register value overrides are =0 with the exception of the nokaslr pseudo feature which uses =1. In order to remove the dependency on kstrtou64(), which is part of the core kernel and no longer usable once we move idreg-override into the early mini C runtime, let's just parse a single hex digit (with optional leading 0x) and set the output value accordingly. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/idreg-override.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 58c02fe20e1050b4..758f0e86e2bd2a34 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -195,6 +195,20 @@ static const struct { { "nokaslr", "arm64_sw.nokaslr=1" }, }; +static int __init parse_hexdigit(const char *p, u64 *v) +{ + // skip "0x" if it comes next + if (p[0] == '0' && tolower(p[1]) == 'x') + p += 2; + + // check whether the RHS is a single hex digit + if (!isxdigit(p[0]) || (p[1] && !isspace(p[1]))) + return -EINVAL; + + *v = tolower(*p) - (isdigit(*p) ? '0' : 'a' - 10); + return 0; +} + static int __init find_field(const char *cmdline, char *opt, int len, const struct ftr_set_desc *reg, int f, u64 *v) { @@ -208,7 +222,7 @@ static int __init find_field(const char *cmdline, char *opt, int len, if (memcmp(cmdline, opt, len)) return -1; - return kstrtou64(cmdline + len, 0, v); + return parse_hexdigit(cmdline + len, v); } static void __init match_options(const char *cmdline)