[PATCH 4.19 137/139] ipv6: Fix data races around sk->sk_prot.

4.19-stable review patch. If anyone has any objections, please let me know.

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From: Kuniyuki Iwashima kuniyu@amazon.com

commit 364f997b5cfe1db0d63a390fe7c801fa2b3115f6 upstream.

Commit 086d49058cd8 ("ipv6: annotate some data-races around sk->sk_prot") fixed some data-races around sk->sk_prot but it was not enough.

Some functions in inet6_(stream|dgram)_ops still access sk->sk_prot without lock_sock() or rtnl_lock(), so they need READ_ONCE() to avoid load tearing.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Kazunori Kobayashi kazunori.kobayashi@miraclelinux.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/sock.c | 6 ++++-- net/ipv4/af_inet.c | 23 ++++++++++++++++------- net/ipv6/ipv6_sockglue.c | 4 ++-- 3 files changed, 22 insertions(+), 11 deletions(-)

--- a/net/core/sock.c +++ b/net/core/sock.c @@ -3064,7 +3064,8 @@ int sock_common_getsockopt(struct socket { struct sock *sk = sock->sk;

- return sk->sk_prot->getsockopt(sk, level, optname, optval, optlen); + /* IPV6_ADDRFORM can change sk->sk_prot under us. */ + return READ_ONCE(sk->sk_prot)->getsockopt(sk, level, optname, optval, optlen); } EXPORT_SYMBOL(sock_common_getsockopt);

@@ -3105,7 +3106,8 @@ int sock_common_setsockopt(struct socket { struct sock *sk = sock->sk;

- return sk->sk_prot->setsockopt(sk, level, optname, optval, optlen); + /* IPV6_ADDRFORM can change sk->sk_prot under us. */ + return READ_ONCE(sk->sk_prot)->setsockopt(sk, level, optname, optval, optlen); } EXPORT_SYMBOL(sock_common_setsockopt);

--- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -553,22 +553,27 @@ int inet_dgram_connect(struct socket *so int addr_len, int flags) { struct sock *sk = sock->sk; + const struct proto *prot; int err;

if (addr_len < sizeof(uaddr->sa_family)) return -EINVAL; + + /* IPV6_ADDRFORM can change sk->sk_prot under us. */ + prot = READ_ONCE(sk->sk_prot); + if (uaddr->sa_family == AF_UNSPEC) - return sk->sk_prot->disconnect(sk, flags); + return prot->disconnect(sk, flags);

if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) { - err = sk->sk_prot->pre_connect(sk, uaddr, addr_len); + err = prot->pre_connect(sk, uaddr, addr_len); if (err) return err; }

if (!inet_sk(sk)->inet_num && inet_autobind(sk)) return -EAGAIN; - return sk->sk_prot->connect(sk, uaddr, addr_len); + return prot->connect(sk, uaddr, addr_len); } EXPORT_SYMBOL(inet_dgram_connect);

@@ -731,10 +736,11 @@ EXPORT_SYMBOL(inet_stream_connect); int inet_accept(struct socket *sock, struct socket *newsock, int flags, bool kern) { - struct sock *sk1 = sock->sk; + struct sock *sk1 = sock->sk, *sk2; int err = -EINVAL; - struct sock *sk2 = sk1->sk_prot->accept(sk1, flags, &err, kern);

+ /* IPV6_ADDRFORM can change sk->sk_prot under us. */ + sk2 = READ_ONCE(sk1->sk_prot)->accept(sk1, flags, &err, kern); if (!sk2) goto do_err;

@@ -809,6 +815,7 @@ ssize_t inet_sendpage(struct socket *soc size_t size, int flags) { struct sock *sk = sock->sk; + const struct proto *prot;

sock_rps_record_flow(sk);

@@ -817,8 +824,10 @@ ssize_t inet_sendpage(struct socket *soc inet_autobind(sk)) return -EAGAIN;

- if (sk->sk_prot->sendpage) - return sk->sk_prot->sendpage(sk, page, offset, size, flags); + /* IPV6_ADDRFORM can change sk->sk_prot under us. */ + prot = READ_ONCE(sk->sk_prot); + if (prot->sendpage) + return prot->sendpage(sk, page, offset, size, flags); return sock_no_sendpage(sock, page, offset, size, flags); } EXPORT_SYMBOL(inet_sendpage); --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -224,7 +224,7 @@ static int do_ipv6_setsockopt(struct soc sock_prot_inuse_add(net, sk->sk_prot, -1); sock_prot_inuse_add(net, &tcp_prot, 1); local_bh_enable(); - /* Paired with READ_ONCE(sk->sk_prot) in net/ipv6/af_inet6.c */ + /* Paired with READ_ONCE(sk->sk_prot) in inet6_stream_ops */ WRITE_ONCE(sk->sk_prot, &tcp_prot); icsk->icsk_af_ops = &ipv4_specific; sk->sk_socket->ops = &inet_stream_ops; @@ -239,7 +239,7 @@ static int do_ipv6_setsockopt(struct soc sock_prot_inuse_add(net, sk->sk_prot, -1); sock_prot_inuse_add(net, prot, 1); local_bh_enable(); - /* Paired with READ_ONCE(sk->sk_prot) in net/ipv6/af_inet6.c */ + /* Paired with READ_ONCE(sk->sk_prot) in inet6_dgram_ops */ WRITE_ONCE(sk->sk_prot, prot); sk->sk_socket->ops = &inet_dgram_ops; sk->sk_family = PF_INET;