From e1dc0615c6b08ef36414f08c011965b8fb56198b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 12 Sep 2023 09:17:24 +0000 Subject: udp: move udp->gro_enabled to udp->udp_flags 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 Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Signed-off-by: Paolo Abeni --- 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 8d4c3835b1b2..b344bd2e41fc 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 cb32826a1db2..1debc10a0f02 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1868,7 +1868,7 @@ try_again: (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(inet)) @@ -2713,7 +2713,7 @@ 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; @@ -2803,7 +2803,7 @@ 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 0f46b3c2e4ac..6c95d28d0c4a 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 6e1ea3029260..2c3281879b6d 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -413,7 +413,7 @@ try_again: (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) -- cgit v1.2.3