From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 07/23] hamradio: baycom_epp: Fix return type of baycom_send_packet() Date: Sun, 18 Dec 2022 11:21:33 -0500 Message-ID: <20221218162149.935047-7-sashal@kernel.org> References: <20221218162149.935047-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671380529; bh=ONuYGq6oB24d94k2QgN3qhxbPTyBa1Lzwbl6aFqLKAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gn0PDFwm4eoWWDpqZx2xVtRfNVHzOUXF1hZQTViVAskwiA2TIltKixjoHmSPPK8lz 3BGQnNVuDZLrzaAJq6sjhYbyXvfqgS7j5DOo60I4U0dyOQsWQIaf4dlkwyZAi3MB0S lRpv3NQiAk2UqaiY0pDoHkcqerSZI7Au5849PBqxlIj9JgYKkxa0Qxhw1i/9XPHtck zUbfVWrcuAoCTmho+xptegKTCgZ56dKbFPCRshN6F5HyH79QEI2NSApGunjRX0fwOz 7vg6NaYc9ND5XRMMU3H3e6rCzNGjkmGpUv9ZLwHDeB6trvP7lWtXqVpVolum3r/Wky KLFW7eqPi7RZw== In-Reply-To: <20221218162149.935047-1-sashal@kernel.org> List-ID: Content-Type: text/plain; charset="us-ascii" 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 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 1503f10122f7..a80948d700fe 100644 --- a/drivers/net/hamradio/baycom_epp.c +++ b/drivers/net/hamradio/baycom_epp.c @@ -772,7 +772,7 @@ 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