From 3679d585bbc07a1ac4448d5b478b492cad3587ce Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 30 Mar 2018 15:08:04 -0700 Subject: net: Introduce __inet_bind() and __inet6_bind Refactor `bind()` code to make it ready to be called from BPF helper function `bpf_bind()` (will be added soon). Implementation of `inet_bind()` and `inet6_bind()` is separated into `__inet_bind()` and `__inet6_bind()` correspondingly. These function can be used from both `sk_prot->bind` and `bpf_bind()` contexts. New functions have two additional arguments. `force_bind_address_no_port` forces binding to IP only w/o checking `inet_sock.bind_address_no_port` field. It'll allow to bind local end of a connection to desired IP in `bpf_bind()` w/o changing `bind_address_no_port` field of a socket. It's useful since `bpf_bind()` can return an error and we'd need to restore original value of `bind_address_no_port` in that case if we changed this before calling to the helper. `with_lock` specifies whether to lock socket when working with `struct sk` or not. The argument is set to `true` for `sk_prot->bind`, i.e. old behavior is preserved. But it will be set to `false` for `bpf_bind()` use-case. The reason is all call-sites, where `bpf_bind()` will be called, already hold that socket lock. Signed-off-by: Andrey Ignatov Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- net/ipv6/af_inet6.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index fa24e3f06ac6..13110bee5c14 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -277,15 +277,7 @@ out_rcu_unlock: /* bind for INET6 API */ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { - struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr; struct sock *sk = sock->sk; - struct inet_sock *inet = inet_sk(sk); - struct ipv6_pinfo *np = inet6_sk(sk); - struct net *net = sock_net(sk); - __be32 v4addr = 0; - unsigned short snum; - bool saved_ipv6only; - int addr_type = 0; int err = 0; /* If the socket has its own bind function then use it. */ @@ -302,11 +294,28 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) if (err) return err; + return __inet6_bind(sk, uaddr, addr_len, false, true); +} +EXPORT_SYMBOL(inet6_bind); + +int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, + bool force_bind_address_no_port, bool with_lock) +{ + struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr; + struct inet_sock *inet = inet_sk(sk); + struct ipv6_pinfo *np = inet6_sk(sk); + struct net *net = sock_net(sk); + __be32 v4addr = 0; + unsigned short snum; + bool saved_ipv6only; + int addr_type = 0; + int err = 0; + if (addr->sin6_family != AF_INET6) return -EAFNOSUPPORT; addr_type = ipv6_addr_type(&addr->sin6_addr); - if ((addr_type & IPV6_ADDR_MULTICAST) && sock->type == SOCK_STREAM) + if ((addr_type & IPV6_ADDR_MULTICAST) && sk->sk_type == SOCK_STREAM) return -EINVAL; snum = ntohs(addr->sin6_port); @@ -314,7 +323,8 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE)) return -EACCES; - lock_sock(sk); + if (with_lock) + lock_sock(sk); /* Check these errors (active socket, double bind). */ if (sk->sk_state != TCP_CLOSE || inet->inet_num) { @@ -402,7 +412,8 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) sk->sk_ipv6only = 1; /* Make sure we are allowed to bind here. */ - if ((snum || !inet->bind_address_no_port) && + if ((snum || !(inet->bind_address_no_port || + force_bind_address_no_port)) && sk->sk_prot->get_port(sk, snum)) { sk->sk_ipv6only = saved_ipv6only; inet_reset_saddr(sk); @@ -418,13 +429,13 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) inet->inet_dport = 0; inet->inet_daddr = 0; out: - release_sock(sk); + if (with_lock) + release_sock(sk); return err; out_unlock: rcu_read_unlock(); goto out; } -EXPORT_SYMBOL(inet6_bind); int inet6_release(struct socket *sock) { -- cgit v1.2.3