From a04a480d4392ea6efd117be2de564117b2a009c0 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Sun, 16 Oct 2016 20:02:52 -0700 Subject: [PATCH] net: Require exact match for TCP socket lookups if dif is l3mdev Currently, socket lookups for l3mdev (vrf) use cases can match a socket that is bound to a port but not a device (ie., a global socket). If the sysctl tcp_l3mdev_accept is not set this leads to ack packets going out based on the main table even though the packet came in from an L3 domain. The end result is that the connection does not establish creating confusion for users since the service is running and a socket shows in ss output. Fix by requiring an exact dif to sk_bound_dev_if match if the skb came through an interface enslaved to an l3mdev device and the tcp_l3mdev_accept is not set. skb's through an l3mdev interface are marked by setting a flag in inet{6}_skb_parm. The IPv6 variant is already set; this patch adds the flag for IPv4. Using an skb flag avoids a device lookup on the dif. The flag is set in the VRF driver using the IP{6}CB macros. For IPv4, the inet_skb_parm struct is moved in the cb per commit 971f10eca186, so the match function in the TCP stack needs to use TCP_SKB_CB. For IPv6, the move is done after the socket lookup, so IP6CB is used. The flags field in inet_skb_parm struct needs to be increased to add another flag. There is currently a 1-byte hole following the flags, so it can be expanded to u16 without increasing the size of the struct. Fixes: 193125dbd8eb ("net: Introduce VRF device driver") Signed-off-by: David Ahern Signed-off-by: David S. Miller --- drivers/net/vrf.c | 2 ++ include/linux/ipv6.h | 17 ++++++++++++++--- include/net/ip.h | 8 +++++++- include/net/tcp.h | 13 ++++++++++++- net/ipv4/inet_hashtables.c | 8 +++++--- net/ipv6/inet6_hashtables.c | 7 ++++--- 6 files changed, 44 insertions(+), 11 deletions(-) diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 85c271c70d42..820de6a9ddde 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -956,6 +956,7 @@ static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev, if (skb->pkt_type == PACKET_LOOPBACK) { skb->dev = vrf_dev; skb->skb_iif = vrf_dev->ifindex; + IP6CB(skb)->flags |= IP6SKB_L3SLAVE; skb->pkt_type = PACKET_HOST; goto out; } @@ -996,6 +997,7 @@ static struct sk_buff *vrf_ip_rcv(struct net_device *vrf_dev, { skb->dev = vrf_dev; skb->skb_iif = vrf_dev->ifindex; + IPCB(skb)->flags |= IPSKB_L3SLAVE; /* loopback traffic; do not push through packet taps again. * Reset pkt_type for upper layers to process skb diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 7e9a789be5e0..ca1ad9ebbc92 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -123,12 +123,12 @@ struct inet6_skb_parm { }; #if defined(CONFIG_NET_L3_MASTER_DEV) -static inline bool skb_l3mdev_slave(__u16 flags) +static inline bool ipv6_l3mdev_skb(__u16 flags) { return flags & IP6SKB_L3SLAVE; } #else -static inline bool skb_l3mdev_slave(__u16 flags) +static inline bool ipv6_l3mdev_skb(__u16 flags) { return false; } @@ -139,11 +139,22 @@ static inline bool skb_l3mdev_slave(__u16 flags) static inline int inet6_iif(const struct sk_buff *skb) { - bool l3_slave = skb_l3mdev_slave(IP6CB(skb)->flags); + bool l3_slave = ipv6_l3mdev_skb(IP6CB(skb)->flags); return l3_slave ? skb->skb_iif : IP6CB(skb)->iif; } +/* can not be used in TCP layer after tcp_v6_fill_cb */ +static inline bool inet6_exact_dif_match(struct net *net, struct sk_buff *skb) +{ +#if defined(CONFIG_NET_L3_MASTER_DEV) + if (!net->ipv4.sysctl_tcp_l3mdev_accept && + ipv6_l3mdev_skb(IP6CB(skb)->flags)) + return true; +#endif + return false; +} + struct tcp6_request_sock { struct tcp_request_sock tcp6rsk_tcp; }; diff --git a/include/net/ip.h b/include/net/ip.h index bc43c0fcae12..c9d07988911e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -38,7 +38,7 @@ struct sock; struct inet_skb_parm { int iif; struct ip_options opt; /* Compiled IP options */ - unsigned char flags; + u16 flags; #define IPSKB_FORWARDED BIT(0) #define IPSKB_XFRM_TUNNEL_SIZE BIT(1) @@ -48,10 +48,16 @@ struct inet_skb_parm { #define IPSKB_DOREDIRECT BIT(5) #define IPSKB_FRAG_PMTU BIT(6) #define IPSKB_FRAG_SEGS BIT(7) +#define IPSKB_L3SLAVE BIT(8) u16 frag_max_size; }; +static inline bool ipv4_l3mdev_skb(u16 flags) +{ + return !!(flags & IPSKB_L3SLAVE); +} + static inline unsigned int ip_hdrlen(const struct sk_buff *skb) { return ip_hdr(skb)->ihl * 4; diff --git a/include/net/tcp.h b/include/net/tcp.h index f83b7f220a65..5b82d4d94834 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -794,12 +794,23 @@ struct tcp_skb_cb { */ static inline int tcp_v6_iif(const struct sk_buff *skb) { - bool l3_slave = skb_l3mdev_slave(TCP_SKB_CB(skb)->header.h6.flags); + bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif; } #endif +/* TCP_SKB_CB reference means this can not be used from early demux */ +static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb) +{ +#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) + if (!net->ipv4.sysctl_tcp_l3mdev_accept && + ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags)) + return true; +#endif + return false; +} + /* Due to TSO, an SKB can be composed of multiple actual * packets. To keep these tracked properly, we use this. */ diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 77c20a489218..ca97835bfec4 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -25,6 +25,7 @@ #include #include #include +#include #include static u32 inet_ehashfn(const struct net *net, const __be32 laddr, @@ -172,7 +173,7 @@ EXPORT_SYMBOL_GPL(__inet_inherit_port); static inline int compute_score(struct sock *sk, struct net *net, const unsigned short hnum, const __be32 daddr, - const int dif) + const int dif, bool exact_dif) { int score = -1; struct inet_sock *inet = inet_sk(sk); @@ -186,7 +187,7 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score += 4; } - if (sk->sk_bound_dev_if) { + if (sk->sk_bound_dev_if || exact_dif) { if (sk->sk_bound_dev_if != dif) return -1; score += 4; @@ -215,11 +216,12 @@ struct sock *__inet_lookup_listener(struct net *net, unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; int score, hiscore = 0, matches = 0, reuseport = 0; + bool exact_dif = inet_exact_dif_match(net, skb); struct sock *sk, *result = NULL; u32 phash = 0; sk_for_each_rcu(sk, &ilb->head) { - score = compute_score(sk, net, hnum, daddr, dif); + score = compute_score(sk, net, hnum, daddr, dif, exact_dif); if (score > hiscore) { reuseport = sk->sk_reuseport; if (reuseport) { diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 00cf28ad4565..2fd0374a35b1 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -96,7 +96,7 @@ EXPORT_SYMBOL(__inet6_lookup_established); static inline int compute_score(struct sock *sk, struct net *net, const unsigned short hnum, const struct in6_addr *daddr, - const int dif) + const int dif, bool exact_dif) { int score = -1; @@ -109,7 +109,7 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score++; } - if (sk->sk_bound_dev_if) { + if (sk->sk_bound_dev_if || exact_dif) { if (sk->sk_bound_dev_if != dif) return -1; score++; @@ -131,11 +131,12 @@ struct sock *inet6_lookup_listener(struct net *net, unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; int score, hiscore = 0, matches = 0, reuseport = 0; + bool exact_dif = inet6_exact_dif_match(net, skb); struct sock *sk, *result = NULL; u32 phash = 0; sk_for_each(sk, &ilb->head) { - score = compute_score(sk, net, hnum, daddr, dif); + score = compute_score(sk, net, hnum, daddr, dif, exact_dif); if (score > hiscore) { reuseport = sk->sk_reuseport; if (reuseport) {