6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 482521d8e0c6520429478aa6866cd44128b33d5d ]
up->pending can be read without holding the socket lock,
as pointed out by syzbot [1]
Add READ_ONCE() in lockless contexts, and WRITE_ONCE()
on write side.
[1]
BUG: KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg
write to 0xffff88814e5eadf0 of 4 bytes by task 15547 on cpu 1:
udpv6_sendmsg+0x1405/0x1530 net/ipv6/udp.c:1596
inet6_sendmsg+0x63/0x80 net/ipv6/af_inet6.c:657
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x257/0x310 net/socket.c:2192
__do_sys_sendto net/socket.c:2204 [inline]
__se_sys_sendto net/socket.c:2200 [inline]
__x64_sys_sendto+0x78/0x90 net/socket.c:2200
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
read to 0xffff88814e5eadf0 of 4 bytes by task 15551 on cpu 0:
udpv6_sendmsg+0x22c/0x1530 net/ipv6/udp.c:1373
inet6_sendmsg+0x63/0x80 net/ipv6/af_inet6.c:657
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x37c/0x4d0 net/socket.c:2586
___sys_sendmsg net/socket.c:2640 [inline]
__sys_sendmmsg+0x269/0x500 net/socket.c:2726
__do_sys_sendmmsg net/socket.c:2755 [inline]
__se_sys_sendmmsg net/socket.c:2752 [inline]
__x64_sys_sendmmsg+0x57/0x60 net/socket.c:2752
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
value changed: 0x00000000 -> 0x0000000a
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15551 Comm: syz-executor.1 Tainted: G W 6.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+8d482d0e407f665d9d10@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/netdev/0000000000009e46c3060ebcdffd@xxxxxxxxxx/
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/udp.c | 12 ++++++------
net/ipv6/udp.c | 16 ++++++++--------
2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c3ff984b6354..bd12a7658213 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -805,7 +805,7 @@ void udp_flush_pending_frames(struct sock *sk)
if (up->pending) {
up->len = 0;
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
ip_flush_pending_frames(sk);
}
}
@@ -993,7 +993,7 @@ int udp_push_pending_frames(struct sock *sk)
out:
up->len = 0;
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
return err;
}
EXPORT_SYMBOL(udp_push_pending_frames);
@@ -1069,7 +1069,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
fl4 = &inet->cork.fl.u.ip4;
- if (up->pending) {
+ if (READ_ONCE(up->pending)) {
/*
* There are pending frames.
* The socket lock must be held while it's corked.
@@ -1265,7 +1265,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
fl4->saddr = saddr;
fl4->fl4_dport = dport;
fl4->fl4_sport = inet->inet_sport;
- up->pending = AF_INET;
+ WRITE_ONCE(up->pending, AF_INET);
do_append_data:
up->len += ulen;
@@ -1277,7 +1277,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
else if (!corkreq)
err = udp_push_pending_frames(sk);
else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
release_sock(sk);
out:
@@ -1315,7 +1315,7 @@ void udp_splice_eof(struct socket *sock)
struct sock *sk = sock->sk;
struct udp_sock *up = udp_sk(sk);
- if (!up->pending || udp_test_bit(CORK, sk))
+ if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk))
return;
lock_sock(sk);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index f60ba4295435..f1170dcc21d9 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1134,7 +1134,7 @@ static void udp_v6_flush_pending_frames(struct sock *sk)
udp_flush_pending_frames(sk);
else if (up->pending) {
up->len = 0;
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
ip6_flush_pending_frames(sk);
}
}
@@ -1312,7 +1312,7 @@ static int udp_v6_push_pending_frames(struct sock *sk)
&inet_sk(sk)->cork.base);
out:
up->len = 0;
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
return err;
}
@@ -1369,7 +1369,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
default:
return -EINVAL;
}
- } else if (!up->pending) {
+ } else if (!READ_ONCE(up->pending)) {
if (sk->sk_state != TCP_ESTABLISHED)
return -EDESTADDRREQ;
daddr = &sk->sk_v6_daddr;
@@ -1400,8 +1400,8 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
return -EMSGSIZE;
getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
- if (up->pending) {
- if (up->pending == AF_INET)
+ if (READ_ONCE(up->pending)) {
+ if (READ_ONCE(up->pending) == AF_INET)
return udp_sendmsg(sk, msg, len);
/*
* There are pending frames.
@@ -1591,7 +1591,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
goto out;
}
- up->pending = AF_INET6;
+ WRITE_ONCE(up->pending, AF_INET6);
do_append_data:
if (ipc6.dontfrag < 0)
@@ -1605,7 +1605,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
else if (!corkreq)
err = udp_v6_push_pending_frames(sk);
else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
- up->pending = 0;
+ WRITE_ONCE(up->pending, 0);
if (err > 0)
err = np->recverr ? net_xmit_errno(err) : 0;
@@ -1646,7 +1646,7 @@ static void udpv6_splice_eof(struct socket *sock)
struct sock *sk = sock->sk;
struct udp_sock *up = udp_sk(sk);
- if (!up->pending || udp_test_bit(CORK, sk))
+ if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk))
return;
lock_sock(sk);
--
2.43.0
