6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit a0002127cd746fcaa182ad3386ef6931c37f3bda ]
syzbot reported that udp->no_check6_tx can be read locklessly.
Use one atomic bit from udp->udp_flags
Fixes: 1c19448c9ba6 ("net: Make enabling of zero UDP6 csums more restrictive")
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/linux/udp.h | 10 +++++-----
net/ipv4/udp.c | 4 ++--
net/ipv6/udp.c | 4 ++--
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 23f0693e0d9cc..e3f2a6c7ac1d1 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -34,6 +34,7 @@ static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
enum {
UDP_FLAGS_CORK, /* Cork is required */
+ UDP_FLAGS_NO_CHECK6_TX, /* Send zero UDP6 checksums on TX? */
};
struct udp_sock {
@@ -47,8 +48,7 @@ struct udp_sock {
int pending; /* Any pending frames ? */
__u8 encap_type; /* Is this an Encapsulation socket? */
- unsigned char no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
- no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
+ unsigned char no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
encap_enabled:1, /* This socket enabled encap
* processing; UDP tunnels and
* different encapsulation layer set
@@ -115,7 +115,7 @@ struct udp_sock {
static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
{
- udp_sk(sk)->no_check6_tx = val;
+ udp_assign_bit(NO_CHECK6_TX, sk, val);
}
static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
@@ -123,9 +123,9 @@ static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
udp_sk(sk)->no_check6_rx = val;
}
-static inline bool udp_get_no_check6_tx(struct sock *sk)
+static inline bool udp_get_no_check6_tx(const struct sock *sk)
{
- return udp_sk(sk)->no_check6_tx;
+ return udp_test_bit(NO_CHECK6_TX, sk);
}
static inline bool udp_get_no_check6_rx(struct sock *sk)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c7873bb4375d0..716eaddc7bdd0 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2719,7 +2719,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_TX:
- up->no_check6_tx = valbool;
+ udp_set_no_check6_tx(sk, valbool);
break;
case UDP_NO_CHECK6_RX:
@@ -2816,7 +2816,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_TX:
- val = up->no_check6_tx;
+ val = udp_get_no_check6_tx(sk);
break;
case UDP_NO_CHECK6_RX:
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 816247afc2f89..c4f82dfa533fe 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1270,7 +1270,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
kfree_skb(skb);
return -EINVAL;
}
- if (udp_sk(sk)->no_check6_tx) {
+ if (udp_get_no_check6_tx(sk)) {
kfree_skb(skb);
return -EINVAL;
}
@@ -1291,7 +1291,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
if (is_udplite)
csum = udplite_csum(skb);
- else if (udp_sk(sk)->no_check6_tx) { /* UDP csum disabled */
+ else if (udp_get_no_check6_tx(sk)) { /* UDP csum disabled */
skb->ip_summed = CHECKSUM_NONE;
goto send;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
--
2.42.0
