![Johannes Berg](/assets/img/avatar_default.png)
We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
183 lines
4.3 KiB
C
183 lines
4.3 KiB
C
/*
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* Copyright (c) 2014 Nicira, Inc.
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* Copyright (c) 2013 Cisco Systems, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/openvswitch.h>
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#include <linux/module.h>
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#include <net/udp.h>
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#include <net/ip_tunnels.h>
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#include <net/rtnetlink.h>
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#include <net/vxlan.h>
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#include "datapath.h"
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#include "vport.h"
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#include "vport-netdev.h"
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static struct vport_ops ovs_vxlan_netdev_vport_ops;
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static int vxlan_get_options(const struct vport *vport, struct sk_buff *skb)
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{
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struct vxlan_dev *vxlan = netdev_priv(vport->dev);
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__be16 dst_port = vxlan->cfg.dst_port;
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if (nla_put_u16(skb, OVS_TUNNEL_ATTR_DST_PORT, ntohs(dst_port)))
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return -EMSGSIZE;
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if (vxlan->cfg.flags & VXLAN_F_GBP) {
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struct nlattr *exts;
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exts = nla_nest_start_noflag(skb, OVS_TUNNEL_ATTR_EXTENSION);
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if (!exts)
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return -EMSGSIZE;
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if (vxlan->cfg.flags & VXLAN_F_GBP &&
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nla_put_flag(skb, OVS_VXLAN_EXT_GBP))
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return -EMSGSIZE;
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nla_nest_end(skb, exts);
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}
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return 0;
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}
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static const struct nla_policy exts_policy[OVS_VXLAN_EXT_MAX + 1] = {
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[OVS_VXLAN_EXT_GBP] = { .type = NLA_FLAG, },
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};
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static int vxlan_configure_exts(struct vport *vport, struct nlattr *attr,
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struct vxlan_config *conf)
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{
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struct nlattr *exts[OVS_VXLAN_EXT_MAX + 1];
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int err;
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if (nla_len(attr) < sizeof(struct nlattr))
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return -EINVAL;
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err = nla_parse_nested_deprecated(exts, OVS_VXLAN_EXT_MAX, attr,
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exts_policy, NULL);
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if (err < 0)
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return err;
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if (exts[OVS_VXLAN_EXT_GBP])
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conf->flags |= VXLAN_F_GBP;
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return 0;
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}
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static struct vport *vxlan_tnl_create(const struct vport_parms *parms)
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{
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struct net *net = ovs_dp_get_net(parms->dp);
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struct nlattr *options = parms->options;
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struct net_device *dev;
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struct vport *vport;
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struct nlattr *a;
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int err;
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struct vxlan_config conf = {
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.no_share = true,
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.flags = VXLAN_F_COLLECT_METADATA | VXLAN_F_UDP_ZERO_CSUM6_RX,
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/* Don't restrict the packets that can be sent by MTU */
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.mtu = IP_MAX_MTU,
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};
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if (!options) {
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err = -EINVAL;
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goto error;
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}
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a = nla_find_nested(options, OVS_TUNNEL_ATTR_DST_PORT);
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if (a && nla_len(a) == sizeof(u16)) {
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conf.dst_port = htons(nla_get_u16(a));
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} else {
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/* Require destination port from userspace. */
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err = -EINVAL;
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goto error;
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}
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vport = ovs_vport_alloc(0, &ovs_vxlan_netdev_vport_ops, parms);
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if (IS_ERR(vport))
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return vport;
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a = nla_find_nested(options, OVS_TUNNEL_ATTR_EXTENSION);
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if (a) {
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err = vxlan_configure_exts(vport, a, &conf);
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if (err) {
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ovs_vport_free(vport);
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goto error;
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}
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}
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rtnl_lock();
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dev = vxlan_dev_create(net, parms->name, NET_NAME_USER, &conf);
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if (IS_ERR(dev)) {
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rtnl_unlock();
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ovs_vport_free(vport);
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return ERR_CAST(dev);
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}
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err = dev_change_flags(dev, dev->flags | IFF_UP, NULL);
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if (err < 0) {
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rtnl_delete_link(dev);
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rtnl_unlock();
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ovs_vport_free(vport);
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goto error;
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}
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rtnl_unlock();
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return vport;
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error:
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return ERR_PTR(err);
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}
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static struct vport *vxlan_create(const struct vport_parms *parms)
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{
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struct vport *vport;
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vport = vxlan_tnl_create(parms);
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if (IS_ERR(vport))
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return vport;
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return ovs_netdev_link(vport, parms->name);
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}
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static struct vport_ops ovs_vxlan_netdev_vport_ops = {
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.type = OVS_VPORT_TYPE_VXLAN,
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.create = vxlan_create,
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.destroy = ovs_netdev_tunnel_destroy,
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.get_options = vxlan_get_options,
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.send = dev_queue_xmit,
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};
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static int __init ovs_vxlan_tnl_init(void)
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{
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return ovs_vport_ops_register(&ovs_vxlan_netdev_vport_ops);
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}
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static void __exit ovs_vxlan_tnl_exit(void)
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{
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ovs_vport_ops_unregister(&ovs_vxlan_netdev_vport_ops);
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}
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module_init(ovs_vxlan_tnl_init);
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module_exit(ovs_vxlan_tnl_exit);
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MODULE_DESCRIPTION("OVS: VXLAN switching port");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("vport-type-4");
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