From 4b1a86281cc1d0de46df3ad2cb8c1f86ac07681c Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Wed, 11 Nov 2020 20:45:25 +0000 Subject: net: udp: fix UDP header access on Fast/frag0 UDP GRO UDP GRO uses udp_hdr(skb) in its .gro_receive() callback. While it's probably OK for non-frag0 paths (when all headers or even the entire frame are already in skb head), this inline points to junk when using Fast GRO (napi_gro_frags() or napi_gro_receive() with only Ethernet header in skb head and all the rest in the frags) and breaks GRO packet compilation and the packet flow itself. To support both modes, skb_gro_header_fast() + skb_gro_header_slow() are typically used. UDP even has an inline helper that makes use of them, udp_gro_udphdr(). Use that instead of troublemaking udp_hdr() to get rid of the out-of-order delivers. Present since the introduction of plain UDP GRO in 5.0-rc1. Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") Cc: Eric Dumazet Signed-off-by: Alexander Lobakin Acked-by: Willem de Bruijn Signed-off-by: Jakub Kicinski --- net/ipv4/udp_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv4/udp_offload.c') diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index e67a66fbf27b..13740e9fe6ec 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -366,7 +366,7 @@ out: static struct sk_buff *udp_gro_receive_segment(struct list_head *head, struct sk_buff *skb) { - struct udphdr *uh = udp_hdr(skb); + struct udphdr *uh = udp_gro_udphdr(skb); struct sk_buff *pp = NULL; struct udphdr *uh2; struct sk_buff *p; -- cgit v1.2.3 From 55e729889bb07d68ab071660ce3f5e7a7872ebe8 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Wed, 11 Nov 2020 20:45:38 +0000 Subject: net: udp: fix IP header access and skb lookup on Fast/frag0 UDP GRO udp{4,6}_lib_lookup_skb() use ip{,v6}_hdr() to get IP header of the packet. While it's probably OK for non-frag0 paths, this helpers will also point to junk on Fast/frag0 GRO when all headers are located in frags. As a result, sk/skb lookup may fail or give wrong results. To support both GRO modes, skb_gro_network_header() might be used. To not modify original functions, add private versions of udp{4,6}_lib_lookup_skb() only to perform correct sk lookups on GRO. Present since the introduction of "application-level" UDP GRO in 4.7-rc1. Misc: replace totally unneeded ternaries with plain ifs. Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket") Suggested-by: Willem de Bruijn Cc: Eric Dumazet Signed-off-by: Alexander Lobakin Acked-by: Willem de Bruijn Signed-off-by: Jakub Kicinski --- net/ipv4/udp_offload.c | 17 +++++++++++++++-- net/ipv6/udp_offload.c | 17 +++++++++++++++-- 2 files changed, 30 insertions(+), 4 deletions(-) (limited to 'net/ipv4/udp_offload.c') diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 13740e9fe6ec..c62805cd3131 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -500,12 +500,22 @@ out: } EXPORT_SYMBOL(udp_gro_receive); +static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport, + __be16 dport) +{ + const struct iphdr *iph = skb_gro_network_header(skb); + + return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport, + iph->daddr, dport, inet_iif(skb), + inet_sdif(skb), &udp_table, NULL); +} + INDIRECT_CALLABLE_SCOPE struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) { struct udphdr *uh = udp_gro_udphdr(skb); + struct sock *sk = NULL; struct sk_buff *pp; - struct sock *sk; if (unlikely(!uh)) goto flush; @@ -523,7 +533,10 @@ struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) skip: NAPI_GRO_CB(skb)->is_ipv6 = 0; rcu_read_lock(); - sk = static_branch_unlikely(&udp_encap_needed_key) ? udp4_lib_lookup_skb(skb, uh->source, uh->dest) : NULL; + + if (static_branch_unlikely(&udp_encap_needed_key)) + sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest); + pp = udp_gro_receive(head, skb, uh, sk); rcu_read_unlock(); return pp; diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 584157a07759..f9e888d1b9af 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -111,12 +111,22 @@ out: return segs; } +static struct sock *udp6_gro_lookup_skb(struct sk_buff *skb, __be16 sport, + __be16 dport) +{ + const struct ipv6hdr *iph = skb_gro_network_header(skb); + + return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport, + &iph->daddr, dport, inet6_iif(skb), + inet6_sdif(skb), &udp_table, NULL); +} + INDIRECT_CALLABLE_SCOPE struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) { struct udphdr *uh = udp_gro_udphdr(skb); + struct sock *sk = NULL; struct sk_buff *pp; - struct sock *sk; if (unlikely(!uh)) goto flush; @@ -135,7 +145,10 @@ struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) skip: NAPI_GRO_CB(skb)->is_ipv6 = 1; rcu_read_lock(); - sk = static_branch_unlikely(&udpv6_encap_needed_key) ? udp6_lib_lookup_skb(skb, uh->source, uh->dest) : NULL; + + if (static_branch_unlikely(&udpv6_encap_needed_key)) + sk = udp6_gro_lookup_skb(skb, uh->source, uh->dest); + pp = udp_gro_receive(head, skb, uh, sk); rcu_read_unlock(); return pp; -- cgit v1.2.3