From 9dbbfb0ab6680c6a85609041011484e6658e7d3c Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 11 Feb 2017 19:26:46 +0800 Subject: [PATCH] tipc: Fix tipc_sk_reinit race conditions There are two problems with the function tipc_sk_reinit. Firstly it's doing a manual walk over an rhashtable. This is broken as an rhashtable can be resized and if you manually walk over it during a resize then you may miss entries. Secondly it's missing memory barriers as previously the code used spinlocks which provide the barriers implicitly. This patch fixes both problems. Fixes: 07f6c4bc048a ("tipc: convert tipc reference table to...") Signed-off-by: Herbert Xu Acked-by: Ying Xue Signed-off-by: David S. Miller --- net/tipc/net.c | 4 ++++ net/tipc/socket.c | 30 +++++++++++++++++++----------- 2 files changed, 23 insertions(+), 11 deletions(-) diff --git a/net/tipc/net.c b/net/tipc/net.c index 28bf4feeb81c..ab8a2d5d1e32 100644 --- a/net/tipc/net.c +++ b/net/tipc/net.c @@ -110,6 +110,10 @@ int tipc_net_start(struct net *net, u32 addr) char addr_string[16]; tn->own_addr = addr; + + /* Ensure that the new address is visible before we reinit. */ + smp_mb(); + tipc_named_reinit(net); tipc_sk_reinit(net); diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 800caaa699a1..370a5912bcb5 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -384,8 +384,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock, INIT_LIST_HEAD(&tsk->publications); msg = &tsk->phdr; tn = net_generic(sock_net(sk), tipc_net_id); - tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG, - NAMED_H_SIZE, 0); /* Finish initializing socket data structures */ sock->ops = ops; @@ -395,6 +393,13 @@ static int tipc_sk_create(struct net *net, struct socket *sock, pr_warn("Socket create failed; port number exhausted\n"); return -EINVAL; } + + /* Ensure tsk is visible before we read own_addr. */ + smp_mb(); + + tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG, + NAMED_H_SIZE, 0); + msg_set_origport(msg, tsk->portid); setup_timer(&sk->sk_timer, tipc_sk_timeout, (unsigned long)tsk); sk->sk_shutdown = 0; @@ -2269,24 +2274,27 @@ static int tipc_sk_withdraw(struct tipc_sock *tsk, uint scope, void tipc_sk_reinit(struct net *net) { struct tipc_net *tn = net_generic(net, tipc_net_id); - const struct bucket_table *tbl; - struct rhash_head *pos; + struct rhashtable_iter iter; struct tipc_sock *tsk; struct tipc_msg *msg; - int i; - rcu_read_lock(); - tbl = rht_dereference_rcu((&tn->sk_rht)->tbl, &tn->sk_rht); - for (i = 0; i < tbl->size; i++) { - rht_for_each_entry_rcu(tsk, pos, tbl, i, node) { + rhashtable_walk_enter(&tn->sk_rht, &iter); + + do { + tsk = ERR_PTR(rhashtable_walk_start(&iter)); + if (tsk) + continue; + + while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) { spin_lock_bh(&tsk->sk.sk_lock.slock); msg = &tsk->phdr; msg_set_prevnode(msg, tn->own_addr); msg_set_orignode(msg, tn->own_addr); spin_unlock_bh(&tsk->sk.sk_lock.slock); } - } - rcu_read_unlock(); + + rhashtable_walk_stop(&iter); + } while (tsk == ERR_PTR(-EAGAIN)); } static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid) -- 2.20.1