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authorAndrey Ignatov <rdna@fb.com>2018-03-30 15:08:04 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-03-31 02:15:43 +0200
commit3679d585bbc07a1ac4448d5b478b492cad3587ce (patch)
tree15cfea104f4ee4dcb55005a2ca101631eefa3f2f /net/ipv4
parentselftests/bpf: Selftest for sys_bind hooks (diff)
downloadlinux-dev-3679d585bbc07a1ac4448d5b478b492cad3587ce.tar.xz
linux-dev-3679d585bbc07a1ac4448d5b478b492cad3587ce.zip
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 <rdna@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/af_inet.c39
1 files changed, 24 insertions, 15 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 2dec266507dc..e203a39d6988 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -432,30 +432,37 @@ EXPORT_SYMBOL(inet_release);
int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
- struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
struct sock *sk = sock->sk;
- struct inet_sock *inet = inet_sk(sk);
- struct net *net = sock_net(sk);
- unsigned short snum;
- int chk_addr_ret;
- u32 tb_id = RT_TABLE_LOCAL;
int err;
/* If the socket has its own bind function then use it. (RAW) */
if (sk->sk_prot->bind) {
- err = sk->sk_prot->bind(sk, uaddr, addr_len);
- goto out;
+ return sk->sk_prot->bind(sk, uaddr, addr_len);
}
- err = -EINVAL;
if (addr_len < sizeof(struct sockaddr_in))
- goto out;
+ return -EINVAL;
/* BPF prog is run before any checks are done so that if the prog
* changes context in a wrong way it will be caught.
*/
err = BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr);
if (err)
- goto out;
+ return err;
+
+ return __inet_bind(sk, uaddr, addr_len, false, true);
+}
+EXPORT_SYMBOL(inet_bind);
+
+int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
+ bool force_bind_address_no_port, bool with_lock)
+{
+ struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
+ struct inet_sock *inet = inet_sk(sk);
+ struct net *net = sock_net(sk);
+ unsigned short snum;
+ int chk_addr_ret;
+ u32 tb_id = RT_TABLE_LOCAL;
+ int err;
if (addr->sin_family != AF_INET) {
/* Compatibility games : accept AF_UNSPEC (mapped to AF_INET)
@@ -499,7 +506,8 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
* would be illegal to use them (multicast/broadcast) in
* which case the sending device address is used.
*/
- lock_sock(sk);
+ if (with_lock)
+ lock_sock(sk);
/* Check these errors (active socket, double bind). */
err = -EINVAL;
@@ -511,7 +519,8 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
inet->inet_saddr = 0; /* Use device */
/* 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)) {
inet->inet_saddr = inet->inet_rcv_saddr = 0;
err = -EADDRINUSE;
@@ -528,11 +537,11 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
sk_dst_reset(sk);
err = 0;
out_release_sock:
- release_sock(sk);
+ if (with_lock)
+ release_sock(sk);
out:
return err;
}
-EXPORT_SYMBOL(inet_bind);
int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)