From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48EA833CA for ; Sun, 18 Dec 2022 16:17:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1214C433EF; Sun, 18 Dec 2022 16:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671380233; bh=jGWV1F/52tDMtlZyzRzbQPCYoETjK1HdqV3sIhSdaYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VIXoPMDKkotwK8Ymm8EE/beKroG9E+F5HX3mT9NtJmIWrLXEXaBSTUETZxI62P3Kv ZmUf3xz9NJAo7WFu2jCgNzVjifQfMHvnntu3iHZHo0UQJZGpGr9pQN6PV0D5tytO5p GFPnIL0Vpjt6pQ/tO/q4llVtn1sh3C++Ic2vLXcfYpPcA1up+OLuiX0lg4/sgTHWUJ o317jehyJw9R0ob/c83vkzZ1JsdCt1ptlWPKp31S9HYLtFlUoLqlw15s6uLJ1Z6emP uAYDD6wptpAXj6GvLITKm6EMn12x8ODU01rKfCUT0Oqum3pp7XGV+wu/x62exNsI6d ooQ9P+iSocleg== 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 5.10 17/39] s390/netiucv: Fix return type of netiucv_tx() Date: Sun, 18 Dec 2022 11:15:37 -0500 Message-Id: <20221218161559.932604-17-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221218161559.932604-1-sashal@kernel.org> References: <20221218161559.932604-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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 260860cf3aa1..a2f403c4ec38 100644 --- a/drivers/s390/net/netiucv.c +++ b/drivers/s390/net/netiucv.c @@ -1260,15 +1260,8 @@ 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