6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit bcbc1b1de884647aa0318bf74eb7f293d72a1e40 ]
syzbot reported that udp->no_check6_rx 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 | 6 +++---
3 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index e3f2a6c7ac1d1..8d4c3835b1b21 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -35,6 +35,7 @@ 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? */
+ UDP_FLAGS_NO_CHECK6_RX, /* Allow zero UDP6 checksums on RX? */
};
struct udp_sock {
@@ -48,8 +49,7 @@ struct udp_sock {
int pending; /* Any pending frames ? */
__u8 encap_type; /* Is this an Encapsulation socket? */
- unsigned char no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
- encap_enabled:1, /* This socket enabled encap
+ unsigned char encap_enabled:1, /* This socket enabled encap
* processing; UDP tunnels and
* different encapsulation layer set
* this
@@ -120,7 +120,7 @@ static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
{
- udp_sk(sk)->no_check6_rx = val;
+ udp_assign_bit(NO_CHECK6_RX, sk, val);
}
static inline bool udp_get_no_check6_tx(const struct sock *sk)
@@ -128,9 +128,9 @@ static inline bool udp_get_no_check6_tx(const struct sock *sk)
return udp_test_bit(NO_CHECK6_TX, sk);
}
-static inline bool udp_get_no_check6_rx(struct sock *sk)
+static inline bool udp_get_no_check6_rx(const struct sock *sk)
{
- return udp_sk(sk)->no_check6_rx;
+ return udp_test_bit(NO_CHECK6_RX, sk);
}
static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 0c6998291c99d..cb32826a1db20 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2698,7 +2698,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_RX:
- up->no_check6_rx = valbool;
+ udp_set_no_check6_rx(sk, valbool);
break;
case UDP_SEGMENT:
@@ -2795,7 +2795,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_RX:
- val = up->no_check6_rx;
+ val = udp_get_no_check6_rx(sk);
break;
case UDP_SEGMENT:
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 469df0ca561f7..6e1ea3029260e 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -858,7 +858,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
/* If zero checksum and no_check is not on for
* the socket then skip it.
*/
- if (!uh->check && !udp_sk(sk)->no_check6_rx)
+ if (!uh->check && !udp_get_no_check6_rx(sk))
continue;
if (!first) {
first = sk;
@@ -980,7 +980,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
udp6_sk_rx_dst_set(sk, dst);
- if (!uh->check && !udp_sk(sk)->no_check6_rx) {
+ if (!uh->check && !udp_get_no_check6_rx(sk)) {
if (refcounted)
sock_put(sk);
goto report_csum_error;
@@ -1002,7 +1002,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
/* Unicast */
sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
if (sk) {
- if (!uh->check && !udp_sk(sk)->no_check6_rx)
+ if (!uh->check && !udp_get_no_check6_rx(sk))
goto report_csum_error;
return udp6_unicast_rcv_skb(sk, skb, uh);
}
--
2.42.0
