sctp: fix the issue that flags are ignored when using kernel_connect

Now sctp uses inet_dgram_connect as its proto_ops .connect, and the flags
param can't be passed into its proto .connect where this flags is really
needed.

sctp works around it by getting flags from socket file in __sctp_connect.
It works for connecting from userspace, as inherently the user sock has
socket file and it passes f_flags as the flags param into the proto_ops
.connect.

However, the sock created by sock_create_kern doesn't have a socket file,
and it passes the flags (like O_NONBLOCK) by using the flags param in
kernel_connect, which calls proto_ops .connect later.

So to fix it, this patch defines a new proto_ops .connect for sctp,
sctp_inet_connect, which calls __sctp_connect() directly with this
flags param. After this, the sctp's proto .connect can be removed.

Note that sctp_inet_connect doesn't need to do some checks that are not
needed for sctp, which makes thing better than with inet_dgram_connect.

Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 37 insertions, 18 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 42247110d842..0cd2e764f47f 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -1006,7 +1006,7 @@ static const struct proto_ops inet6_seqpacket_ops = {
         .owner             = THIS_MODULE,
         .release           = inet6_release,
         .bind              = inet6_bind,
-        .connect           = inet_dgram_connect,
+        .connect           = sctp_inet_connect,
         .socketpair        = sock_no_socketpair,
         .accept            = inet_accept,
         .getname           = sctp_getname,
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index d685f8456762..6bf0a9971888 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1012,7 +1012,7 @@ static const struct proto_ops inet_seqpacket_ops = {
         .owner             = THIS_MODULE,
         .release           = inet_release,      /* Needs to be wrapped... */
         .bind              = inet_bind,
-        .connect           = inet_dgram_connect,
+        .connect           = sctp_inet_connect,
         .socketpair        = sock_no_socketpair,
         .accept            = inet_accept,
         .getname           = inet_getname,      /* Semantics are different.  */
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 80835ac26d2c..ae7e7c606f72 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1086,7 +1086,7 @@ out:
  */
 static int __sctp_connect(struct sock *sk,
                           struct sockaddr *kaddrs,
-                          int addrs_size,
+                          int addrs_size, int flags,
                           sctp_assoc_t *assoc_id)
 {
         struct net *net = sock_net(sk);
@@ -1104,7 +1104,6 @@ static int __sctp_connect(struct sock *sk,
         union sctp_addr *sa_addr = NULL;
         void *addr_buf;
         unsigned short port;
-        unsigned int f_flags = 0;
 
         sp = sctp_sk(sk);
         ep = sp->ep;
@@ -1254,13 +1253,7 @@ static int __sctp_connect(struct sock *sk,
         sp->pf->to_sk_daddr(sa_addr, sk);
         sk->sk_err = 0;
 
-        /* in-kernel sockets don't generally have a file allocated to them
-         * if all they do is call sock_create_kern().
-         */
-        if (sk->sk_socket->file)
-                f_flags = sk->sk_socket->file->f_flags;
-
-        timeo = sock_sndtimeo(sk, f_flags & O_NONBLOCK);
+        timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 
         if (assoc_id)
                 *assoc_id = asoc->assoc_id;
@@ -1348,7 +1341,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
                                       sctp_assoc_t *assoc_id)
 {
         struct sockaddr *kaddrs;
-        int err = 0;
+        int err = 0, flags = 0;
 
         pr_debug("%s: sk:%p addrs:%p addrs_size:%d\n",
                  __func__, sk, addrs, addrs_size);
@@ -1367,7 +1360,13 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
         if (err)
                 goto out_free;
 
-        err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
+        /* in-kernel sockets don't generally have a file allocated to them
+         * if all they do is call sock_create_kern().
+         */
+        if (sk->sk_socket->file)
+                flags = sk->sk_socket->file->f_flags;
+
+        err = __sctp_connect(sk, kaddrs, addrs_size, flags, assoc_id);
 
 out_free:
         kvfree(kaddrs);
@@ -4397,16 +4396,26 @@ out_nounlock:
  * len: the size of the address.
  */
 static int sctp_connect(struct sock *sk, struct sockaddr *addr,
-                        int addr_len)
+                        int addr_len, int flags)
 {
-        int err = 0;
+        struct inet_sock *inet = inet_sk(sk);
         struct sctp_af *af;
+        int err = 0;
 
         lock_sock(sk);
 
         pr_debug("%s: sk:%p, sockaddr:%p, addr_len:%d\n", __func__, sk,
                  addr, addr_len);
 
+        /* We may need to bind the socket. */
+        if (!inet->inet_num) {
+                if (sk->sk_prot->get_port(sk, 0)) {
+                        release_sock(sk);
+                        return -EAGAIN;
+                }
+                inet->inet_sport = htons(inet->inet_num);
+        }
+
         /* Validate addr_len before calling common connect/connectx routine. */
         af = sctp_get_af_specific(addr->sa_family);
         if (!af || addr_len < af->sockaddr_len) {
@@ -4415,13 +4424,25 @@ static int sctp_connect(struct sock *sk, struct sockaddr *addr,
                 /* Pass correct addr len to common routine (so it knows there
                  * is only one address being passed.
                  */
-                err = __sctp_connect(sk, addr, af->sockaddr_len, NULL);
+                err = __sctp_connect(sk, addr, af->sockaddr_len, flags, NULL);
         }
 
         release_sock(sk);
         return err;
 }
 
+int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
+                      int addr_len, int flags)
+{
+        if (addr_len < sizeof(uaddr->sa_family))
+                return -EINVAL;
+
+        if (uaddr->sa_family == AF_UNSPEC)
+                return -EOPNOTSUPP;
+
+        return sctp_connect(sock->sk, uaddr, addr_len, flags);
+}
+
 /* FIXME: Write comments. */
 static int sctp_disconnect(struct sock *sk, int flags)
 {
@@ -8724,7 +8745,6 @@ struct proto sctp_prot = {
         .name        =  "SCTP",
         .owner       =  THIS_MODULE,
         .close       =  sctp_close,
-        .connect     =  sctp_connect,
         .disconnect  =  sctp_disconnect,
         .accept      =  sctp_accept,
         .ioctl       =  sctp_ioctl,
@@ -8767,7 +8787,6 @@ struct proto sctpv6_prot = {
         .name           = "SCTPv6",
         .owner          = THIS_MODULE,
         .close          = sctp_close,
-        .connect        = sctp_connect,
         .disconnect     = sctp_disconnect,
         .accept         = sctp_accept,
         .ioctl          = sctp_ioctl,