6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit e1dc0615c6b08ef36414f08c011965b8fb56198b ]
syzbot reported that udp->gro_enabled can be read locklessly.
Use one atomic bit from udp->udp_flags.
Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.")
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 | 2 +-
net/ipv4/udp.c | 6 +++---
net/ipv4/udp_offload.c | 4 ++--
net/ipv6/udp.c | 2 +-
4 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 8d4c3835b1b21..b344bd2e41fc9 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -36,6 +36,7 @@ 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? */
+ UDP_FLAGS_GRO_ENABLED, /* Request GRO aggregation */
};
struct udp_sock {
@@ -54,7 +55,6 @@ struct udp_sock {
* different encapsulation layer set
* this
*/
- gro_enabled:1, /* Request GRO aggregation */
accept_udp_l4:1,
accept_udp_fraglist:1;
/* indicator bits used by pcflag: */
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 6b1754704acd1..a160fce601acb 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1897,7 +1897,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
(struct sockaddr *)sin);
}
- if (udp_sk(sk)->gro_enabled)
+ if (udp_test_bit(GRO_ENABLED, sk))
udp_cmsg_recv(msg, sk, skb);
if (inet->cmsg_flags)
@@ -2738,7 +2738,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
/* when enabling GRO, accept the related GSO packet type */
if (valbool)
udp_tunnel_encap_enable(sk->sk_socket);
- up->gro_enabled = valbool;
+ udp_assign_bit(GRO_ENABLED, sk, valbool);
up->accept_udp_l4 = valbool;
release_sock(sk);
break;
@@ -2828,7 +2828,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
break;
case UDP_GRO:
- val = up->gro_enabled;
+ val = udp_test_bit(GRO_ENABLED, sk);
break;
/* The following two cannot be changed on UDP sockets, the return is
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 0f46b3c2e4ac5..6c95d28d0c4a7 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -557,10 +557,10 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
NAPI_GRO_CB(skb)->is_flist = 0;
if (!sk || !udp_sk(sk)->gro_receive) {
if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
- NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled : 1;
+ NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
- (sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
+ (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
return call_gro_receive(udp_gro_receive_segment, head, skb);
/* no GRO, be sure flush the current packet */
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1df116951f5eb..3e9497418758f 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -446,7 +446,7 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
(struct sockaddr *)sin6);
}
- if (udp_sk(sk)->gro_enabled)
+ if (udp_test_bit(GRO_ENABLED, sk))
udp_cmsg_recv(msg, sk, skb);
if (np->rxopt.all)
--
2.42.0
