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ipv6: Fix data races around sk->sk_prot.

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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>
This commit is contained in:
Kuniyuki Iwashima 2022-10-06 11:53:48 -07:00 committed by Jakub Kicinski
parent d38afeec26
commit 364f997b5c
3 changed files with 22 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
net/core/sock.c
View File

@ -3610,7 +3610,8 @@ int sock_common_getsockopt(struct socket *sock, int level, int optname,
{ {
struct sock *sk = sock->sk; 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); EXPORT_SYMBOL(sock_common_getsockopt);
@ -3636,7 +3637,8 @@ int sock_common_setsockopt(struct socket *sock, int level, int optname,
{ {
struct sock *sk = sock->sk; 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); EXPORT_SYMBOL(sock_common_setsockopt);

23
net/ipv4/af_inet.c
View File

@ -558,22 +558,27 @@ int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags) int addr_len, int flags)
{ {
struct sock *sk = sock->sk; struct sock *sk = sock->sk;
const struct proto *prot;
int err; int err;
if (addr_len < sizeof(uaddr->sa_family)) if (addr_len < sizeof(uaddr->sa_family))
return -EINVAL; return -EINVAL;
/* IPV6_ADDRFORM can change sk->sk_prot under us. */
prot = READ_ONCE(sk->sk_prot);
if (uaddr->sa_family == AF_UNSPEC) 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)) { 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) if (err)
return err; return err;
} }
if (data_race(!inet_sk(sk)->inet_num) && inet_autobind(sk)) if (data_race(!inet_sk(sk)->inet_num) && inet_autobind(sk))
return -EAGAIN; return -EAGAIN;
return sk->sk_prot->connect(sk, uaddr, addr_len); return prot->connect(sk, uaddr, addr_len);
} }
EXPORT_SYMBOL(inet_dgram_connect); EXPORT_SYMBOL(inet_dgram_connect);
@ -734,10 +739,11 @@ EXPORT_SYMBOL(inet_stream_connect);
int inet_accept(struct socket *sock, struct socket *newsock, int flags, int inet_accept(struct socket *sock, struct socket *newsock, int flags,
bool kern) bool kern)
{ {
struct sock *sk1 = sock->sk; struct sock *sk1 = sock->sk, *sk2;
int err = -EINVAL; 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) if (!sk2)
goto do_err; goto do_err;
@ -825,12 +831,15 @@ ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset,
size_t size, int flags) size_t size, int flags)
{ {
struct sock *sk = sock->sk; struct sock *sk = sock->sk;
const struct proto *prot;
if (unlikely(inet_send_prepare(sk))) if (unlikely(inet_send_prepare(sk)))
return -EAGAIN; return -EAGAIN;
if (sk->sk_prot->sendpage) /* IPV6_ADDRFORM can change sk->sk_prot under us. */
return sk->sk_prot->sendpage(sk, page, offset, size, flags); 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); return sock_no_sendpage(sock, page, offset, size, flags);
} }
EXPORT_SYMBOL(inet_sendpage); EXPORT_SYMBOL(inet_sendpage);

4
net/ipv6/ipv6_sockglue.c
View File

@ -477,7 +477,7 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
sock_prot_inuse_add(net, sk->sk_prot, -1); sock_prot_inuse_add(net, sk->sk_prot, -1);
sock_prot_inuse_add(net, &tcp_prot, 1); sock_prot_inuse_add(net, &tcp_prot, 1);
/* 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); WRITE_ONCE(sk->sk_prot, &tcp_prot);
icsk->icsk_af_ops = &ipv4_specific; icsk->icsk_af_ops = &ipv4_specific;
sk->sk_socket->ops = &inet_stream_ops; sk->sk_socket->ops = &inet_stream_ops;
@ -492,7 +492,7 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
sock_prot_inuse_add(net, sk->sk_prot, -1); sock_prot_inuse_add(net, sk->sk_prot, -1);
sock_prot_inuse_add(net, prot, 1); sock_prot_inuse_add(net, prot, 1);
/* 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); WRITE_ONCE(sk->sk_prot, prot);
sk->sk_socket->ops = &inet_dgram_ops; sk->sk_socket->ops = &inet_dgram_ops;
sk->sk_family = PF_INET; sk->sk_family = PF_INET;