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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F64EC4167B for ; Thu, 7 Dec 2023 22:57:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443998AbjLGW5W (ORCPT ); Thu, 7 Dec 2023 17:57:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232695AbjLGW5I (ORCPT ); Thu, 7 Dec 2023 17:57:08 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4812198C; Thu, 7 Dec 2023 14:57:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=e9QlfSVQ0gZy3QbK9bpFVf9dp3zXzuooGWrQsidX1tw=; b=J/9J1Z9e94VygRiQ0xxPn9Vy+A mRXXH8imkqLsqqEWTQMcjJPYDnyKNctzuIQ1jKFyT3fLAEc/cZnfgIFnZ9UFtG9DXfDs2Ds+Whvct ggxqcS4rwbiS8T6IYLfeWVUyk3gQL++sRVRMfqFsbSXZ9f5xtVFg7bh2UnKAxwPAXCxddlxrMfkjK 7bDv3CFy0quiiQZn2IEm5/QHUt3b1HcrD5hDnLWJKs5abwu40vhV8s3FYYTwT1D02wgk63Z6z7hhM B3D33sVdXuclRaHhnopgO1MXvj/xfl0akDmuJfVcp8zAKm3oLeTXg1gYw5Y73zK622TFyOV7OXYmr nmRQuJww==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57030) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rBNIn-0001ka-1u; Thu, 07 Dec 2023 22:57:05 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1rBNIo-00047T-K2; Thu, 07 Dec 2023 22:57:06 +0000 Date: Thu, 7 Dec 2023 22:57:06 +0000 From: "Russell King (Oracle)" To: Justin Stitt Cc: Andrew Lunn , Heiner Kallweit , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v2] net: mdio-gpio: replace deprecated strncpy with strscpy Message-ID: References: <20231207-strncpy-drivers-net-mdio-mdio-gpio-c-v2-1-c28d52dd3dfe@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231207-strncpy-drivers-net-mdio-mdio-gpio-c-v2-1-c28d52dd3dfe@google.com> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 07, 2023 at 09:54:31PM +0000, Justin Stitt wrote: > We expect new_bus->id to be NUL-terminated but not NUL-padded based on > its prior assignment through snprintf: > | snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); > > We can also use sizeof() instead of a length macro as this more closely > ties the maximum buffer size to the destination buffer. Honestly, this looks machine generated and unreviewed by the submitter, because... > if (bus_id != -1) > snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); > else > - strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE); > + strscpy(new_bus->id, "gpio", sizeof(new_bus->id)); If there is an argument for not using MII_BUS_ID_SIZE in one place, then the very same argument applies to snprintf(). If one place changes the other also needs to be changed. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!