From ee2875566868687a95b8ec23913c0d6bce220efd Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 5 May 2020 19:22:14 +0200 Subject: [PATCH] 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: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.") Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Signed-off-by: David S. Miller --- drivers/net/bareudp.c | 18 ++++-------------- include/net/udp_tunnel.h | 2 -- 2 files changed, 4 insertions(+), 16 deletions(-) diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c index cc0703c3d57f..efd1a1d1f35e 100644 --- a/drivers/net/bareudp.c +++ b/drivers/net/bareudp.c @@ -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; } diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h index 4b1f95e08307..e7312ceb2794 100644 --- a/include/net/udp_tunnel.h +++ b/include/net/udp_tunnel.h @@ -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);