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| author |   Jon Maloy <jon.maloy@ericsson.com> | 2018-01-17 16:42:46 +0100 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-01-19 15:12:21 -0500 |
| commit | 60c2530696320ee6ffe4491c17079fa403790c98 (patch) | |
| tree | 619bdaecd86e48c1962a6866e40ada7e09c5addc /net/tipc/socket.c | |
| parent | l2tp: remove switch block in l2tp_nl_cmd_session_create() (diff) | |
| download | linux-dev-60c2530696320ee6ffe4491c17079fa403790c98.tar.xz linux-dev-60c2530696320ee6ffe4491c17079fa403790c98.zip | |
tipc: fix race between poll() and setsockopt()
Letting tipc_poll() dereference a socket's pointer to struct tipc_group
entails a race risk, as the group item may be deleted in a concurrent
tipc_sk_join() or tipc_sk_leave() thread.
We now move the 'open' flag in struct tipc_group to struct tipc_sock,
and let the former retain only a pointer to the moved field. This will
eliminate the race risk.
Reported-by: syzbot+799dafde0286795858ac@syzkaller.appspotmail.com
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
| -rw-r--r-- | net/tipc/socket.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c index d799e50ff722..473a096b6fba 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -116,6 +116,7 @@ struct tipc_sock { struct tipc_mc_method mc_method; struct rcu_head rcu; struct tipc_group *group; + bool group_is_open; }; static int tipc_sk_backlog_rcv(struct sock *sk, struct sk_buff *skb); @@ -715,7 +716,6 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock, { struct sock *sk = sock->sk; struct tipc_sock *tsk = tipc_sk(sk); - struct tipc_group *grp; u32 revents = 0; sock_poll_wait(file, sk_sleep(sk), wait); @@ -736,8 +736,7 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock, revents |= POLLIN | POLLRDNORM; break; case TIPC_OPEN: - grp = tsk->group; - if ((!grp || tipc_group_is_open(grp)) && !tsk->cong_link_cnt) + if (tsk->group_is_open && !tsk->cong_link_cnt) revents |= POLLOUT; if (!tipc_sk_type_connectionless(sk)) break; @@ -2758,7 +2757,7 @@ static int tipc_sk_join(struct tipc_sock *tsk, struct tipc_group_req *mreq) return -EINVAL; if (grp) return -EACCES; - grp = tipc_group_create(net, tsk->portid, mreq); + grp = tipc_group_create(net, tsk->portid, mreq, &tsk->group_is_open); if (!grp) return -ENOMEM; tsk->group = grp; |