Commit 26afa868 authored by Daniel P. Berrangé's avatar Daniel P. Berrangé Committed by Paolo Bonzini
Browse files

nbd: make server compliant with fixed newstyle spec 



If the client does not request the fixed new style protocol,
then we should only accept NBD_OPT_EXPORT_NAME. All other
options are only valid when fixed new style has been activated.

The qemu-nbd client doesn't currently request fixed new style
protocol, but this change won't break qemu-nbd, because it
fortunately only ever uses NBD_OPT_EXPORT_NAME, so was never
triggering the non-compliant server behaviour.

Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-9-git-send-email-berrange@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f72d705f

nbd/server.c

+46 −23
Original line number Diff line number Diff line
@@ -310,6 +310,7 @@ fail: 
static int nbd_negotiate_options(NBDClient *client)

{

    uint32_t flags;

    bool fixedNewstyle = false;



    /* Client sends:

        [ 0 ..   3]   client flags
@@ -332,14 +333,19 @@ static int nbd_negotiate_options(NBDClient *client) 
    }

    TRACE("Checking client flags");

    be32_to_cpus(&flags);

    if (flags != 0 && flags != NBD_FLAG_C_FIXED_NEWSTYLE) {

        LOG("Bad client flags received");

    if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {

        TRACE("Support supports fixed newstyle handshake");

        fixedNewstyle = true;

        flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;

    }

    if (flags != 0) {

        TRACE("Unknown client flags 0x%x received", flags);

        return -EIO;

    }



    while (1) {

        int ret;

        uint32_t tmp, length;

        uint32_t clientflags, length;

        uint64_t magic;



        if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) !=
@@ -353,10 +359,12 @@ static int nbd_negotiate_options(NBDClient *client) 
            return -EINVAL;

        }



        if (nbd_negotiate_read(client->ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {

        if (nbd_negotiate_read(client->ioc, &clientflags,

                               sizeof(clientflags)) != sizeof(clientflags)) {

            LOG("read failed");

            return -EINVAL;

        }

        clientflags = be32_to_cpu(clientflags);



        if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) !=

            sizeof(length)) {
@@ -365,8 +373,9 @@ static int nbd_negotiate_options(NBDClient *client) 
        }

        length = be32_to_cpu(length);



        TRACE("Checking option");

        switch (be32_to_cpu(tmp)) {

        TRACE("Checking option 0x%x", clientflags);

        if (fixedNewstyle) {

            switch (clientflags) {

            case NBD_OPT_LIST:

                ret = nbd_negotiate_handle_list(client, length);

                if (ret < 0) {
@@ -381,11 +390,25 @@ static int nbd_negotiate_options(NBDClient *client) 
                return nbd_negotiate_handle_export_name(client, length);



            default:

            tmp = be32_to_cpu(tmp);

            LOG("Unsupported option 0x%x", tmp);

            nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, tmp);

                TRACE("Unsupported option 0x%x", clientflags);

                nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP,

                                       clientflags);

                return -EINVAL;

            }

        } else {

            /*

             * If broken new-style we should drop the connection

             * for anything except NBD_OPT_EXPORT_NAME

             */

            switch (clientflags) {

            case NBD_OPT_EXPORT_NAME:

                return nbd_negotiate_handle_export_name(client, length);



            default:

                TRACE("Unsupported option 0x%x", clientflags);

                return -EINVAL;

            }

        }

    }

}