From 16d706b7f54731a13c28b1968450ecf8f4d8b2a6 Mon Sep 17 00:00:00 2001 From: Mike Manning Date: Tue, 9 Apr 2019 04:48:33 +0000 Subject: [PATCH] net: ensure unbound datagram socket to be chosen when not in a VRF mainline inclusion from mainline-v5.0 commit 6da5b0f027a8 category: bugfix bugzilla: 9289 CVE: NA ------------------------------------------------- Ensure an unbound datagram skt is chosen when not in a VRF. The check for a device match in compute_score() for UDP must be performed when there is no device match. For this, a failure is returned when there is no device match. This ensures that bound sockets are never selected, even if there is no unbound socket. Allow IPv6 packets to be sent over a datagram skt bound to a VRF. These packets are currently blocked, as flowi6_oif was set to that of the master vrf device, and the ipi6_ifindex is that of the slave device. Allow these packets to be sent by checking the device with ipi6_ifindex has the same L3 scope as that of the bound device of the skt, which is the master vrf device. Note that this check always succeeds if the skt is unbound. Even though the right datagram skt is now selected by compute_score(), a different skt is being returned that is bound to the wrong vrf. The difference between these and stream sockets is the handling of the skt option for SO_REUSEPORT. While the handling when adding a skt for reuse correctly checks that the bound device of the skt is a match, the skts in the hashslot are already incorrect. So for the same hash, a skt for the wrong vrf may be selected for the required port. The root cause is that the skt is immediately placed into a slot when it is created, but when the skt is then bound using SO_BINDTODEVICE, it remains in the same slot. The solution is to move the skt to the correct slot by forcing a rehash. Signed-off-by: Mike Manning Reviewed-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Lin Miaohe Reviewed-by: Keefe LIU Signed-off-by: Yang Yingliang --- include/net/udp.h | 11 +++++++++++ net/core/sock.c | 2 ++ net/ipv4/udp.c | 15 ++++++--------- net/ipv6/datagram.c | 10 +++++++--- net/ipv6/udp.c | 14 +++++--------- 5 files changed, 31 insertions(+), 21 deletions(-) diff --git a/include/net/udp.h b/include/net/udp.h index 8482a990b0bb..4d82cabd733c 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -252,6 +252,17 @@ static inline int udp_rqueue_get(struct sock *sk) return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); } +static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, + int dif, int sdif) +{ +#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) + return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept, + bound_dev_if, dif, sdif); +#else + return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); +#endif +} + /* net/ipv4/udp.c */ void udp_destruct_sock(struct sock *sk); void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); diff --git a/net/core/sock.c b/net/core/sock.c index b03649737ea8..aa45fa0c9b1c 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -567,6 +567,8 @@ static int sock_setbindtodevice(struct sock *sk, char __user *optval, lock_sock(sk); sk->sk_bound_dev_if = index; + if (sk->sk_prot->rehash) + sk->sk_prot->rehash(sk); sk_dst_reset(sk); release_sock(sk); diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e45a5e19e509..99b1c3dfcc13 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -371,6 +371,7 @@ static int compute_score(struct sock *sk, struct net *net, { int score; struct inet_sock *inet; + bool dev_match; if (!net_eq(sock_net(sk), net) || udp_sk(sk)->udp_port_hash != hnum || @@ -398,15 +399,11 @@ static int compute_score(struct sock *sk, struct net *net, score += 4; } - if (sk->sk_bound_dev_if || exact_dif) { - bool dev_match = (sk->sk_bound_dev_if == dif || - sk->sk_bound_dev_if == sdif); - - if (!dev_match) - return -1; - if (sk->sk_bound_dev_if) - score += 4; - } + dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, + dif, sdif); + if (!dev_match) + return -1; + score += 4; if (sk->sk_incoming_cpu == raw_smp_processor_id()) score++; diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index cb24850d2c7f..ee4a4e54d016 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -771,6 +771,7 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, case IPV6_2292PKTINFO: { struct net_device *dev = NULL; + int src_idx; if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) { err = -EINVAL; @@ -778,12 +779,15 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, } src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg); + src_idx = src_info->ipi6_ifindex; - if (src_info->ipi6_ifindex) { + if (src_idx) { if (fl6->flowi6_oif && - src_info->ipi6_ifindex != fl6->flowi6_oif) + src_idx != fl6->flowi6_oif && + (sk->sk_bound_dev_if != fl6->flowi6_oif || + !sk_dev_equal_l3scope(sk, src_idx))) return -EINVAL; - fl6->flowi6_oif = src_info->ipi6_ifindex; + fl6->flowi6_oif = src_idx; } addr_type = __ipv6_addr_type(&src_info->ipi6_addr); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index cab8b2b647f9..1b04e98ac057 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -117,6 +117,7 @@ static int compute_score(struct sock *sk, struct net *net, { int score; struct inet_sock *inet; + bool dev_match; if (!net_eq(sock_net(sk), net) || udp_sk(sk)->udp_port_hash != hnum || @@ -144,15 +145,10 @@ static int compute_score(struct sock *sk, struct net *net, score++; } - if (sk->sk_bound_dev_if || exact_dif) { - bool dev_match = (sk->sk_bound_dev_if == dif || - sk->sk_bound_dev_if == sdif); - - if (!dev_match) - return -1; - if (sk->sk_bound_dev_if) - score++; - } + dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif); + if (!dev_match) + return -1; + score++; if (sk->sk_incoming_cpu == raw_smp_processor_id()) score++; -- GitLab