diff mbox series

[net,3/3] netlink: annotate data races around sk_state

Message ID 20230120125955.3453768-4-edumazet@google.com (mailing list archive)
State Accepted
Commit 9b663b5cbb15b494ef132a3c937641c90646eb73
Delegated to: Netdev Maintainers
Headers show
Series netlink: annotate various data races | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers warning 1 maintainers not CCed: keescook@chromium.org
netdev/build_clang success Errors and warnings before: 1 this patch: 1
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Jan. 20, 2023, 12:59 p.m. UTC 
netlink_getsockbyportid() reads sk_state while a concurrent
netlink_connect() can change its value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/netlink/af_netlink.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b5b8c6a5fc34205c849ab2ca105cc44ffb407623..c6427765975318b4c7fe3d5291dc4d69988f5249 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1098,7 +1098,8 @@  static int netlink_connect(struct socket *sock, struct sockaddr *addr,
 		return -EINVAL;
 
 	if (addr->sa_family == AF_UNSPEC) {
-		sk->sk_state	= NETLINK_UNCONNECTED;
+		/* 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);
@@ -1122,7 +1123,8 @@  static int netlink_connect(struct socket *sock, struct sockaddr *addr,
 		err = netlink_autobind(sock);
 
 	if (err == 0) {
-		sk->sk_state	= NETLINK_CONNECTED;
+		/* 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));
@@ -1174,8 +1176,8 @@  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 &&
+	/* 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);