diff options
Diffstat (limited to 'net/netlink/af_netlink.c')
| -rw-r--r-- | net/netlink/af_netlink.c | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index bca2a470ccad..c64277659753 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -580,7 +580,9 @@ static int netlink_insert(struct sock *sk, u32 portid) if (nlk_sk(sk)->bound) goto err; - nlk_sk(sk)->portid = portid; + /* portid can be read locklessly from netlink_getname(). */ + WRITE_ONCE(nlk_sk(sk)->portid, portid); + sock_hold(sk); err = __netlink_insert(table, sk); @@ -1096,9 +1098,11 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, return -EINVAL; if (addr->sa_family == AF_UNSPEC) { - sk->sk_state = NETLINK_UNCONNECTED; - nlk->dst_portid = 0; - nlk->dst_group = 0; + /* paired with READ_ONCE() in netlink_getsockbyportid() */ + WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED); + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, 0); + WRITE_ONCE(nlk->dst_group, 0); return 0; } if (addr->sa_family != AF_NETLINK) @@ -1119,9 +1123,11 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, err = netlink_autobind(sock); if (err == 0) { - sk->sk_state = NETLINK_CONNECTED; - nlk->dst_portid = nladdr->nl_pid; - nlk->dst_group = ffs(nladdr->nl_groups); + /* paired with READ_ONCE() in netlink_getsockbyportid() */ + WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED); + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid); + WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups)); } return err; @@ -1138,10 +1144,12 @@ static int netlink_getname(struct socket *sock, struct sockaddr *addr, nladdr->nl_pad = 0; if (peer) { - nladdr->nl_pid = nlk->dst_portid; - nladdr->nl_groups = netlink_group_mask(nlk->dst_group); + /* Paired with WRITE_ONCE() in netlink_connect() */ + nladdr->nl_pid = READ_ONCE(nlk->dst_portid); + nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group)); } else { - nladdr->nl_pid = nlk->portid; + /* Paired with WRITE_ONCE() in netlink_insert() */ + nladdr->nl_pid = READ_ONCE(nlk->portid); netlink_lock_table(); nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; netlink_unlock_table(); @@ -1168,8 +1176,9 @@ static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) /* Don't bother queuing skb if kernel socket has no input function */ nlk = nlk_sk(sock); - if (sock->sk_state == NETLINK_CONNECTED && - nlk->dst_portid != nlk_sk(ssk)->portid) { + /* dst_portid and sk_state can be changed in netlink_connect() */ + if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED && + READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) { sock_put(sock); return ERR_PTR(-ECONNREFUSED); } @@ -1886,8 +1895,9 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) goto out; netlink_skb_flags |= NETLINK_SKB_DST; } else { - dst_portid = nlk->dst_portid; - dst_group = nlk->dst_group; + /* Paired with WRITE_ONCE() in netlink_connect() */ + dst_portid = READ_ONCE(nlk->dst_portid); + dst_group = READ_ONCE(nlk->dst_group); } /* Paired with WRITE_ONCE() in netlink_insert() */ |