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    Subject[PATCH 4.14 91/95] sctp: fix the issue that flags are ignored when using kernel_connect
    Date
    From: Xin Long <lucien.xin@gmail.com>

    commit 644fbdeacf1d3edd366e44b8ba214de9d1dd66a9 upstream.

    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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/net/sctp/sctp.h | 2 +
    net/sctp/ipv6.c | 2 -
    net/sctp/protocol.c | 2 -
    net/sctp/socket.c | 56 ++++++++++++++++++++++++++++++++----------------
    4 files changed, 42 insertions(+), 20 deletions(-)

    --- a/include/net/sctp/sctp.h
    +++ b/include/net/sctp/sctp.h
    @@ -103,6 +103,8 @@ void sctp_addr_wq_mgmt(struct net *, str
    /*
    * sctp/socket.c
    */
    +int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
    + int addr_len, int flags);
    int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
    int sctp_inet_listen(struct socket *sock, int backlog);
    void sctp_write_space(struct sock *sk);
    --- a/net/sctp/ipv6.c
    +++ b/net/sctp/ipv6.c
    @@ -974,7 +974,7 @@ static const struct proto_ops inet6_seqp
    .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,
    --- a/net/sctp/protocol.c
    +++ b/net/sctp/protocol.c
    @@ -1019,7 +1019,7 @@ static const struct proto_ops inet_seqpa
    .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. */
    --- a/net/sctp/socket.c
    +++ b/net/sctp/socket.c
    @@ -1076,7 +1076,7 @@ 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);
    @@ -1094,7 +1094,6 @@ static int __sctp_connect(struct sock *s
    union sctp_addr *sa_addr = NULL;
    void *addr_buf;
    unsigned short port;
    - unsigned int f_flags = 0;

    sp = sctp_sk(sk);
    ep = sp->ep;
    @@ -1244,13 +1243,7 @@ static int __sctp_connect(struct sock *s
    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;
    @@ -1345,7 +1338,7 @@ static int __sctp_setsockopt_connectx(st
    {
    struct sockaddr *kaddrs;
    gfp_t gfp = GFP_KERNEL;
    - int err = 0;
    + int err = 0, flags = 0;

    pr_debug("%s: sk:%p addrs:%p addrs_size:%d\n",
    __func__, sk, addrs, addrs_size);
    @@ -1365,11 +1358,18 @@ static int __sctp_setsockopt_connectx(st
    return -ENOMEM;

    if (__copy_from_user(kaddrs, addrs, addrs_size)) {
    - err = -EFAULT;
    - } else {
    - err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
    + kfree(kaddrs);
    + return -EFAULT;
    }

    + /* 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);
    +
    kfree(kaddrs);

    return err;
    @@ -4166,16 +4166,26 @@ 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) {
    @@ -4184,13 +4194,25 @@ static int sctp_connect(struct sock *sk,
    /* 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)
    {
    @@ -8298,7 +8320,6 @@ struct proto sctp_prot = {
    .name = "SCTP",
    .owner = THIS_MODULE,
    .close = sctp_close,
    - .connect = sctp_connect,
    .disconnect = sctp_disconnect,
    .accept = sctp_accept,
    .ioctl = sctp_ioctl,
    @@ -8337,7 +8358,6 @@ struct proto sctpv6_prot = {
    .name = "SCTPv6",
    .owner = THIS_MODULE,
    .close = sctp_close,
    - .connect = sctp_connect,
    .disconnect = sctp_disconnect,
    .accept = sctp_accept,
    .ioctl = sctp_ioctl,

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