From 4790998fdd0d0c682512af9b4a875bc80da73836 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 4 Feb 2022 12:15:45 -0800 Subject: [PATCH] ipv6: make mc_forwarding atomic [ Upstream commit 145c7a793838add5e004e7d49a67654dc7eba147 ] This fixes minor data-races in ip6_mc_input() and batadv_mcast_mla_rtr_flags_softif_get_ipv6() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/linux/ipv6.h | 2 +- net/batman-adv/multicast.c | 2 +- net/ipv6/addrconf.c | 4 ++-- net/ipv6/ip6_input.c | 2 +- net/ipv6/ip6mr.c | 8 ++++---- 5 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 07cba0b..d1f3864 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -51,7 +51,7 @@ struct ipv6_devconf { __s32 use_optimistic; #endif #ifdef CONFIG_IPV6_MROUTE - __s32 mc_forwarding; + atomic_t mc_forwarding; #endif __s32 disable_ipv6; __s32 drop_unicast_in_l2_multicast; diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index 6e3419b..2853634 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -134,7 +134,7 @@ static u8 batadv_mcast_mla_rtr_flags_softif_get_ipv6(struct net_device *dev) { struct inet6_dev *in6_dev = __in6_dev_get(dev); - if (in6_dev && in6_dev->cnf.mc_forwarding) + if (in6_dev && atomic_read(&in6_dev->cnf.mc_forwarding)) return BATADV_NO_FLAGS; else return BATADV_MCAST_WANT_NO_RTR6; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 1fe2780..3a8838b 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -552,7 +552,7 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, #ifdef CONFIG_IPV6_MROUTE if ((all || type == NETCONFA_MC_FORWARDING) && nla_put_s32(skb, NETCONFA_MC_FORWARDING, - devconf->mc_forwarding) < 0) + atomic_read(&devconf->mc_forwarding)) < 0) goto nla_put_failure; #endif if ((all || type == NETCONFA_PROXY_NEIGH) && @@ -5537,7 +5537,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_USE_OPTIMISTIC] = cnf->use_optimistic; #endif #ifdef CONFIG_IPV6_MROUTE - array[DEVCONF_MC_FORWARDING] = cnf->mc_forwarding; + array[DEVCONF_MC_FORWARDING] = atomic_read(&cnf->mc_forwarding); #endif array[DEVCONF_DISABLE_IPV6] = cnf->disable_ipv6; array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad; diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index 8025671..d4b1e2c 100644 --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -508,7 +508,7 @@ int ip6_mc_input(struct sk_buff *skb) /* * IPv6 multicast router mode is now supported ;) */ - if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && + if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) && !(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) && likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 6a4065d..91f1c5f 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -739,7 +739,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify, in6_dev = __in6_dev_get(dev); if (in6_dev) { - in6_dev->cnf.mc_forwarding--; + atomic_dec(&in6_dev->cnf.mc_forwarding); inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, dev->ifindex, &in6_dev->cnf); @@ -907,7 +907,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt, in6_dev = __in6_dev_get(dev); if (in6_dev) { - in6_dev->cnf.mc_forwarding++; + atomic_inc(&in6_dev->cnf.mc_forwarding); inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, dev->ifindex, &in6_dev->cnf); @@ -1557,7 +1557,7 @@ static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk) } else { rcu_assign_pointer(mrt->mroute_sk, sk); sock_set_flag(sk, SOCK_RCU_FREE); - net->ipv6.devconf_all->mc_forwarding++; + atomic_inc(&net->ipv6.devconf_all->mc_forwarding); } write_unlock_bh(&mrt_lock); @@ -1590,7 +1590,7 @@ int ip6mr_sk_done(struct sock *sk) * so the RCU grace period before sk freeing * is guaranteed by sk_destruct() */ - net->ipv6.devconf_all->mc_forwarding--; + atomic_dec(&net->ipv6.devconf_all->mc_forwarding); write_unlock_bh(&mrt_lock); inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, -- 2.7.4