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 9D4338494 for ; Thu, 5 Jan 2023 13:06:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1401EC433EF; Thu, 5 Jan 2023 13:06:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672923990; bh=+Y5rY6Spr69G3yO6EVScjdi7yjQxdJZoDsPcAT51BN8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R1tRCvecVmVmZkJd/viyO+uBUN3EbSZEJBRir9CPlsIc5oI/yAp1O34I1q8CtcxOa eBYRDzHNY/H2tHK390Ed+dFd96DFl4hqY2TU9nqtgewZjywyjrulLFqh2eJDEVSRcN oI5Lv0VQ4wP1hGNk47/fl4LgEOZ2vJBzuhLufFTU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nathan Chancellor , Kees Cook , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.9 191/251] hamradio: baycom_epp: Fix return type of baycom_send_packet() Date: Thu, 5 Jan 2023 13:55:28 +0100 Message-Id: <20230105125343.560498918@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230105125334.727282894@linuxfoundation.org> References: <20230105125334.727282894@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 78dbc44540f6..b7831d0fd084 100644 --- a/drivers/net/hamradio/baycom_epp.c +++ b/drivers/net/hamradio/baycom_epp.c @@ -768,7 +768,7 @@ 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