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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E039C54EAA for ; Mon, 30 Jan 2023 21:40:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231350AbjA3VkT (ORCPT ); Mon, 30 Jan 2023 16:40:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230104AbjA3VkP (ORCPT ); Mon, 30 Jan 2023 16:40:15 -0500 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A04011727 for ; Mon, 30 Jan 2023 13:40:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1675114814; x=1706650814; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=VdG1GGA8W0DfnPFwDcohOqulqfW3saP77d/Ow4pY9zI=; b=KNTZ9IGxF0iuFD3oUdMIY02uE6iRC9MsJXJY5Khs8hbwe4wgOO7weLpu 1wwdPGPRjCCfGIhphPK4YYhoOhjGLudy5PW5tTuwJLQ92k2orEtg+wxR5 IdCAThhuFhbqYHPdnEKsnpFOaj1W2tExpmGdSQgvW3h84gk9EQqOjC59m kD02y9abNJWRVNf5ROwRGULrmE4b+JBgf6/5HSZD7rDqc5Yb7EjulYFbc 5H0k0IkgLBVyqTeL/xXmMq+yOY+WTneH7TV+6VkNLj8yiYwFIuU0KO7om E1XlWtIf+Ni4wyRvYi9MMRdiQECWjvhR7piM6B2R/ywqGOqSjb3QPJ7m9 g==; X-IronPort-AV: E=McAfee;i="6500,9779,10606"; a="328955492" X-IronPort-AV: E=Sophos;i="5.97,259,1669104000"; d="scan'208";a="328955492" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2023 13:40:12 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10606"; a="696571860" X-IronPort-AV: E=Sophos;i="5.97,259,1669104000"; d="scan'208";a="696571860" Received: from araj-ucode.jf.intel.com ([10.23.0.19]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2023 13:40:12 -0800 From: Ashok Raj To: Borislav Petkov , Thomas Gleixner Cc: Ashok Raj , LKML , x86 , Ingo Molnar , Tony Luck , Dave Hansen , Alison Schofield , Reinette Chatre , Tom Lendacky , Stefan Talpalaru , David Woodhouse , Benjamin Herrenschmidt , Jonathan Corbet , "Rafael J . Wysocki" , Peter Zilstra , Andy Lutomirski , Andrew Cooper , Boris Ostrovsky , Martin Pohlack Subject: [Patch v3 Part2 2/9] x86/microcode: Report invalid writes to reload sysfs file Date: Mon, 30 Jan 2023 13:39:48 -0800 Message-Id: <20230130213955.6046-3-ashok.raj@intel.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230130213955.6046-1-ashok.raj@intel.com> References: <20230130213955.6046-1-ashok.raj@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Semantics of the microcode reload file are only defined if a "1" is written. But the code silently treats any other unsigned integer as a successful write even though no actions are performed to load microcode. Report those erroneous writes back to user. Suggested-by: Thomas Gleixner Signed-off-by: Ashok Raj Cc: LKML Cc: x86 Cc: Ingo Molnar Cc: Tony Luck Cc: Dave Hansen Cc: Alison Schofield Cc: Reinette Chatre Cc: Thomas Gleixner (Intel) Cc: Tom Lendacky Cc: Stefan Talpalaru Cc: David Woodhouse Cc: Benjamin Herrenschmidt Cc: Jonathan Corbet Cc: Rafael J. Wysocki Cc: Peter Zilstra (Intel) Cc: Andy Lutomirski Cc: Andrew Cooper Cc: Boris Ostrovsky Cc: Martin Pohlack --- arch/x86/kernel/cpu/microcode/core.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 1c6831b8b244..e4b4dfcf2d18 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -476,11 +476,8 @@ static ssize_t reload_store(struct device *dev, ssize_t ret; ret = kstrtoul(buf, 0, &val); - if (ret) - return ret; - - if (val != 1) - return size; + if (ret || val != 1) + return -EINVAL; cpus_read_lock(); -- 2.37.2