This is a note to let you know that I've just added the patch titled udp: never accept GSO_FRAGLIST packets to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: udp-never-accept-gso_fraglist-packets.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit fa9b0e2ca65bcd9dfaa0c29c43aee0cef61c8152 Author: Paolo Abeni <pabeni@xxxxxxxxxx> Date: Tue Mar 30 12:28:52 2021 +0200 udp: never accept GSO_FRAGLIST packets [ Upstream commit 78352f73dc5047f3f744764cc45912498c52f3c9 ] Currently the UDP protocol delivers GSO_FRAGLIST packets to the sockets without the expected segmentation. This change addresses the issue introducing and maintaining a couple of new fields to explicitly accept SKB_GSO_UDP_L4 or GSO_FRAGLIST packets. Additionally updates udp_unexpected_gso() accordingly. UDP sockets enabling UDP_GRO stil keep accept_udp_fraglist zeroed. v1 -> v2: - use 2 bits instead of a whole GSO bitmask (Willem) Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/linux/udp.h b/include/linux/udp.h index aa84597bdc33..ae58ff3b6b5b 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -51,7 +51,9 @@ struct udp_sock { * different encapsulation layer set * this */ - gro_enabled:1; /* Can accept GRO packets */ + gro_enabled:1, /* Request GRO aggregation */ + accept_udp_l4:1, + accept_udp_fraglist:1; /* * Following member retains the information to create a UDP header * when the socket is uncorked. @@ -131,8 +133,16 @@ static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk, static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb) { - return !udp_sk(sk)->gro_enabled && skb_is_gso(skb) && - skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4; + if (!skb_is_gso(skb)) + return false; + + if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && !udp_sk(sk)->accept_udp_l4) + return true; + + if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST && !udp_sk(sk)->accept_udp_fraglist) + return true; + + return false; } #define udp_portaddr_for_each_entry(__sk, list) \ diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 4a2fd286787c..9d28b2778e8f 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2657,9 +2657,12 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, case UDP_GRO: lock_sock(sk); + + /* when enabling GRO, accept the related GSO packet type */ if (valbool) udp_tunnel_encap_enable(sk->sk_socket); up->gro_enabled = valbool; + up->accept_udp_l4 = valbool; release_sock(sk); break;