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netlink: annotate data races around dst_portid and dst_group

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[ Upstream commit 004db64d185a5f23dfb891d7701e23713b2420ee ]

netlink_getname(), netlink_sendmsg() and netlink_getsockbyportid()
can read nlk->dst_portid and nlk->dst_group while another
thread is changing them.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Dumazet 2023-01-20 12:59:54 +00:00 committed by Greg Kroah-Hartman
parent eccb532ada
commit 8583f52c23
1 changed files with 14 additions and 9 deletions
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23
net/netlink/af_netlink.c
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@ -1082,8 +1082,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
if (addr->sa_family == AF_UNSPEC) {
sk->sk_state = NETLINK_UNCONNECTED;
nlk->dst_portid = 0;
nlk->dst_group = 0;
/* 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)
@ -1105,8 +1106,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
if (err == 0) {
sk->sk_state = NETLINK_CONNECTED;
nlk->dst_portid = nladdr->nl_pid;
nlk->dst_group = ffs(nladdr->nl_groups);
/* 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;
@ -1123,8 +1125,9 @@ 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 {
/* Paired with WRITE_ONCE() in netlink_insert() */
nladdr->nl_pid = READ_ONCE(nlk->portid);
@ -1154,8 +1157,9 @@ 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);
/* dst_portid can be changed in netlink_connect() */
if (sock->sk_state == NETLINK_CONNECTED &&
nlk->dst_portid != nlk_sk(ssk)->portid) {
READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) {
sock_put(sock);
return ERR_PTR(-ECONNREFUSED);
}
@ -1891,8 +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() */