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 CD0DCC4332F for ; Sun, 18 Dec 2022 16:07:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231526AbiLRQH4 (ORCPT ); Sun, 18 Dec 2022 11:07:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230499AbiLRQFE (ORCPT ); Sun, 18 Dec 2022 11:05:04 -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 C9C60BC36; Sun, 18 Dec 2022 08:03:59 -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 7E32BB80BA5; Sun, 18 Dec 2022 16:03:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF6DFC43398; Sun, 18 Dec 2022 16:03:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671379437; bh=35qg6hjhsveC4cadPh8VkshppfXL78Z16HjjR3pai2E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lzoc60EQJLIN4ZVFrt2RQZdn1LIVVxkOe1UJyvT9n77Rp6EE4d3XQr8DCDC41EGS0 mzT0You6wfAVLPiJmanCJiH+B/XC8k6DYGL6noWftRIbenSqeSzvS6Yw0NGY6fs6/9 mT4EktFBbi6j2eJoaNX2ai8K+iVeDho416p7rEhg+TBkMURSAojLIXt2OV8Y0jX7Dr tEMhGbByScfr2YbEvUZy76jMpKB4EJVxtw5h9tV9aQ98knQlNowTnosbcjFAeiIiEP qIYs7WjWAw+19GmWekvGQSgtIV5ulfrIDKg/BCDEYqWX0kYoU/Mx0Z6WVVne8nBXxc 4KzPHRe280rZg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Chancellor , Alexandra Winter , Kees Cook , "David S . Miller" , Sasha Levin , wenjia@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, ndesaulniers@google.com, linux-s390@vger.kernel.org, netdev@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 6.1 34/85] s390/netiucv: Fix return type of netiucv_tx() Date: Sun, 18 Dec 2022 11:00:51 -0500 Message-Id: <20221218160142.925394-34-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221218160142.925394-1-sashal@kernel.org> References: <20221218160142.925394-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nathan Chancellor [ Upstream commit 88d86d18d7cf7e9137c95f9d212bb9fff8a1b4be ] With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/s390/net/netiucv.c:1854:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict] .ndo_start_xmit = netiucv_tx, ^~~~~~~~~~ ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of netiucv_tx() to match the prototype's to resolve the warning and potential CFI failure, should s390 select ARCH_SUPPORTS_CFI_CLANG in the future. Additionally, while in the area, remove a comment block that is no longer relevant. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Reviewed-by: Alexandra Winter Reviewed-by: Kees Cook Signed-off-by: Nathan Chancellor Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/s390/net/netiucv.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c index 65aa0a96c21d..66076cada8ae 100644 --- a/drivers/s390/net/netiucv.c +++ b/drivers/s390/net/netiucv.c @@ -1248,15 +1248,8 @@ static int netiucv_close(struct net_device *dev) /* * Start transmission of a packet. * Called from generic network device layer. - * - * @param skb Pointer to buffer containing the packet. - * @param dev Pointer to interface struct. - * - * @return 0 if packet consumed, !0 if packet rejected. - * Note: If we return !0, then the packet is free'd by - * the generic network layer. */ -static int netiucv_tx(struct sk_buff *skb, struct net_device *dev) +static netdev_tx_t netiucv_tx(struct sk_buff *skb, struct net_device *dev) { struct netiucv_priv *privptr = netdev_priv(dev); int rc; -- 2.35.1