Commit ee287556 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

net: bareudp: avoid uninitialized variable warning 



clang points out that building without IPv6 would lead to returning
an uninitialized variable if a packet with family!=AF_INET is
passed into bareudp_udp_encap_recv():

drivers/net/bareudp.c:139:6: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        if (family == AF_INET)
            ^~~~~~~~~~~~~~~~~
drivers/net/bareudp.c:146:15: note: uninitialized use occurs here
        if (unlikely(err)) {
                     ^~~
include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
 # define unlikely(x)    __builtin_expect(!!(x), 0)
                                            ^
drivers/net/bareudp.c:139:2: note: remove the 'if' if its condition is always true
        if (family == AF_INET)
        ^~~~~~~~~~~~~~~~~~~~~~

This cannot happen in practice, so change the condition in a way that
gcc sees the IPv4 case as unconditionally true here.
For consistency, change all the similar constructs in this file the
same way, using "if(IS_ENABLED())" instead of #if IS_ENABLED()".

Fixes: 571912c6 ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8aef1994

drivers/net/bareudp.c

+4 −14
Original line number Diff line number Diff line
@@ -136,25 +136,21 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 
	oiph = skb_network_header(skb);

	skb_reset_network_header(skb);



	if (family == AF_INET)

	if (!IS_ENABLED(CONFIG_IPV6) || family == AF_INET)

		err = IP_ECN_decapsulate(oiph, skb);

#if IS_ENABLED(CONFIG_IPV6)

	else

		err = IP6_ECN_decapsulate(oiph, skb);

#endif



	if (unlikely(err)) {

		if (log_ecn_error) {

			if  (family == AF_INET)

			if  (!IS_ENABLED(CONFIG_IPV6) || family == AF_INET)

				net_info_ratelimited("non-ECT from %pI4 "

						     "with TOS=%#x\n",

						     &((struct iphdr *)oiph)->saddr,

						     ((struct iphdr *)oiph)->tos);

#if IS_ENABLED(CONFIG_IPV6)

			else

				net_info_ratelimited("non-ECT from %pI6\n",

						     &((struct ipv6hdr *)oiph)->saddr);

#endif

		}

		if (err > 1) {

			++bareudp->dev->stats.rx_frame_errors;
@@ -350,7 +346,6 @@ free_dst: 
	return err;

}



#if IS_ENABLED(CONFIG_IPV6)

static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,

			     struct bareudp_dev *bareudp,

			     const struct ip_tunnel_info *info)
@@ -411,7 +406,6 @@ free_dst: 
	dst_release(dst);

	return err;

}

#endif



static netdev_tx_t bareudp_xmit(struct sk_buff *skb, struct net_device *dev)

{
@@ -435,11 +429,9 @@ static netdev_tx_t bareudp_xmit(struct sk_buff *skb, struct net_device *dev) 
	}



	rcu_read_lock();

#if IS_ENABLED(CONFIG_IPV6)

	if (info->mode & IP_TUNNEL_INFO_IPV6)

	if (IS_ENABLED(CONFIG_IPV6) && info->mode & IP_TUNNEL_INFO_IPV6)

		err = bareudp6_xmit_skb(skb, dev, bareudp, info);

	else

#endif

		err = bareudp_xmit_skb(skb, dev, bareudp, info);



	rcu_read_unlock();
@@ -467,7 +459,7 @@ static int bareudp_fill_metadata_dst(struct net_device *dev, 


	use_cache = ip_tunnel_dst_cache_usable(skb, info);



	if (ip_tunnel_info_af(info) == AF_INET) {

	if (!IS_ENABLED(CONFIG_IPV6) || ip_tunnel_info_af(info) == AF_INET) {

		struct rtable *rt;

		__be32 saddr;
@@ -478,7 +470,6 @@ static int bareudp_fill_metadata_dst(struct net_device *dev, 


		ip_rt_put(rt);

		info->key.u.ipv4.src = saddr;

#if IS_ENABLED(CONFIG_IPV6)

	} else if (ip_tunnel_info_af(info) == AF_INET6) {

		struct dst_entry *dst;

		struct in6_addr saddr;
@@ -492,7 +483,6 @@ static int bareudp_fill_metadata_dst(struct net_device *dev, 


		dst_release(dst);

		info->key.u.ipv6.src = saddr;

#endif

	} else {

		return -EINVAL;

	}

include/net/udp_tunnel.h

+0 −2
Original line number Diff line number Diff line
@@ -143,14 +143,12 @@ void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb 
			 __be16 df, __be16 src_port, __be16 dst_port,

			 bool xnet, bool nocheck);



#if IS_ENABLED(CONFIG_IPV6)

int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,

			 struct sk_buff *skb,

			 struct net_device *dev, struct in6_addr *saddr,

			 struct in6_addr *daddr,

			 __u8 prio, __u8 ttl, __be32 label,

			 __be16 src_port, __be16 dst_port, bool nocheck);

#endif



void udp_tunnel_sock_release(struct socket *sock);

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