6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit d0f95894fda7d4f895b29c1097f92d7fee278cb2 ]
syzbot caught another data-race in netlink when
setting sk->sk_err.
Annotate all of them for good measure.
BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg
write to 0xffff8881613bb220 of 4 bytes by task 28147 on cpu 0:
netlink_recvmsg+0x448/0x780 net/netlink/af_netlink.c:1994
sock_recvmsg_nosec net/socket.c:1027 [inline]
sock_recvmsg net/socket.c:1049 [inline]
__sys_recvfrom+0x1f4/0x2e0 net/socket.c:2229
__do_sys_recvfrom net/socket.c:2247 [inline]
__se_sys_recvfrom net/socket.c:2243 [inline]
__x64_sys_recvfrom+0x78/0x90 net/socket.c:2243
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
write to 0xffff8881613bb220 of 4 bytes by task 28146 on cpu 1:
netlink_recvmsg+0x448/0x780 net/netlink/af_netlink.c:1994
sock_recvmsg_nosec net/socket.c:1027 [inline]
sock_recvmsg net/socket.c:1049 [inline]
__sys_recvfrom+0x1f4/0x2e0 net/socket.c:2229
__do_sys_recvfrom net/socket.c:2247 [inline]
__se_sys_recvfrom net/socket.c:2243 [inline]
__x64_sys_recvfrom+0x78/0x90 net/socket.c:2243
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x00000000 -> 0x00000016
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28146 Comm: syz-executor.0 Not tainted 6.6.0-rc3-syzkaller-00055-g9ed22ae6be81 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231003183455.3410550-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netlink/af_netlink.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 20082171f24a3..9c6bc47bc7f7b 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -352,7 +352,7 @@ static void netlink_overrun(struct sock *sk)
if (!nlk_test_bit(RECV_NO_ENOBUFS, sk)) {
if (!test_and_set_bit(NETLINK_S_CONGESTED,
&nlk_sk(sk)->state)) {
- sk->sk_err = ENOBUFS;
+ WRITE_ONCE(sk->sk_err, ENOBUFS);
sk_error_report(sk);
}
}
@@ -1577,7 +1577,7 @@ static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
goto out;
}
- sk->sk_err = p->code;
+ WRITE_ONCE(sk->sk_err, p->code);
sk_error_report(sk);
out:
return ret;
@@ -1966,7 +1966,7 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
ret = netlink_dump(sk);
if (ret) {
- sk->sk_err = -ret;
+ WRITE_ONCE(sk->sk_err, -ret);
sk_error_report(sk);
}
}
@@ -2485,7 +2485,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
err_bad_put:
nlmsg_free(skb);
err_skb:
- NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
+ WRITE_ONCE(NETLINK_CB(in_skb).sk->sk_err, ENOBUFS);
sk_error_report(NETLINK_CB(in_skb).sk);
}
EXPORT_SYMBOL(netlink_ack);
--
2.40.1
