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 9A92BC4167B for ; Sun, 18 Dec 2022 16:55:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232870AbiLRQzA (ORCPT ); Sun, 18 Dec 2022 11:55:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232779AbiLRQx7 (ORCPT ); Sun, 18 Dec 2022 11:53:59 -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 8B73511809; Sun, 18 Dec 2022 08:19:06 -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 047BBB80BA8; Sun, 18 Dec 2022 16:19:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BCA7C433EF; Sun, 18 Dec 2022 16:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671380344; bh=j33FzNOjty8cwb7uB4R6TuLexzKBjCt16wxLrBMyoo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WaLwhNTqSUeiORZeEN4mF6AIHlHRvNHx2WVnjShFVEeBUf/DpeOYC7NCUXoGbDzlb YMisU01bsUbQ6qVpFTtIrx9c+OHnM9b1IyRlgFF47LnKqa/fAKIN0NynfhaHrGbQyG amcD53k8dE3PSMopkjU1GKQzS+MhlPY67YhXKPlOlxHWe9ottegcfKD6ya+nl/fjo5 zPlePqYe7qNiBALYXttUw+uc6Bt5vnlajJwyEExOwgfCpEZPw44dppPZLovP5Z9ji9 KU7LNjg312f4bp3khoYFRJSYRzUnY83F04eppLjMyUJVLUs8WLvci3Nspz1rfWncQx cEYdzRqHha5Jw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Chancellor , Kees Cook , Jakub Kicinski , Sasha Levin , t.sailer@alumni.ethz.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, ndesaulniers@google.com, linux-hams@vger.kernel.org, netdev@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 5.4 09/30] hamradio: baycom_epp: Fix return type of baycom_send_packet() Date: Sun, 18 Dec 2022 11:18:14 -0500 Message-Id: <20221218161836.933697-9-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221218161836.933697-1-sashal@kernel.org> References: <20221218161836.933697-1-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: netdev@vger.kernel.org From: Nathan Chancellor [ Upstream commit c5733e5b15d91ab679646ec3149e192996a27d5d ] 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/net/hamradio/baycom_epp.c:1119:25: 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 = baycom_send_packet, ^~~~~~~~~~~~~~~~~~ 1 error generated. ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of baycom_send_packet() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20221102160610.1186145-1-nathan@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/hamradio/baycom_epp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c index 4476491b58f9..c5495ca5e8e6 100644 --- a/drivers/net/hamradio/baycom_epp.c +++ b/drivers/net/hamradio/baycom_epp.c @@ -758,7 +758,7 @@ static void epp_bh(struct work_struct *work) * ===================== network driver interface ========================= */ -static int baycom_send_packet(struct sk_buff *skb, struct net_device *dev) +static netdev_tx_t baycom_send_packet(struct sk_buff *skb, struct net_device *dev) { struct baycom_state *bc = netdev_priv(dev); -- 2.35.1