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 5DA7DC54EBE for ; Mon, 16 Jan 2023 16:37:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233588AbjAPQhz (ORCPT ); Mon, 16 Jan 2023 11:37:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233445AbjAPQhT (ORCPT ); Mon, 16 Jan 2023 11:37:19 -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 3B11E2366A for ; Mon, 16 Jan 2023 08:26:20 -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 BCB70B8107D for ; Mon, 16 Jan 2023 16:26:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1006CC433EF; Mon, 16 Jan 2023 16:26:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673886377; bh=oiOX472mnnmwJmFbj2f3WMF3509uMFauEYkBPuIU34Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qzSDHU24qVP+rKvZ07pfcqDQ+AoghH5CuLMpIdzNcum3mwoRmJyT39ujLPJsdoSUW o6euKJR1Z3f6katSfsO3AwD7zVGi5j1/2zb+0NoMrElQyO9oBlaAmH87jVnbGq1FNy JpUVvw9uNMrEt3TGehkXVjN631tn1gIYvt3qtv7I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexandra Winter , Kees Cook , Nathan Chancellor , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 407/658] s390/netiucv: Fix return type of netiucv_tx() Date: Mon, 16 Jan 2023 16:48:15 +0100 Message-Id: <20230116154928.223461536@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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 5ce2424ca729..e2984b54447b 100644 --- a/drivers/s390/net/netiucv.c +++ b/drivers/s390/net/netiucv.c @@ -1344,15 +1344,8 @@ static int netiucv_pm_restore_thaw(struct 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