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linux/net/bridge/br_netlink_tunnel.c
Johannes Berg 8cb081746c netlink: make validation more configurable for future strictness 
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>
2019-04-27 17:07:21 -04:00

299 lines
7.0 KiB
C
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/*
* Bridge per vlan tunnel port dst_metadata netlink control interface
*
* Authors:
* Roopa Prabhu <roopa@cumulusnetworks.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/etherdevice.h>
#include <net/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <uapi/linux/if_bridge.h>
#include <net/dst_metadata.h>
#include "br_private.h"
#include "br_private_tunnel.h"
static size_t __get_vlan_tinfo_size(void)
{
return nla_total_size(0) + /* nest IFLA_BRIDGE_VLAN_TUNNEL_INFO */
nla_total_size(sizeof(u32)) + /* IFLA_BRIDGE_VLAN_TUNNEL_ID */
nla_total_size(sizeof(u16)) + /* IFLA_BRIDGE_VLAN_TUNNEL_VID */
nla_total_size(sizeof(u16)); /* IFLA_BRIDGE_VLAN_TUNNEL_FLAGS */
}
static bool vlan_tunid_inrange(struct net_bridge_vlan *v_curr,
struct net_bridge_vlan *v_last)
{
__be32 tunid_curr = tunnel_id_to_key32(v_curr->tinfo.tunnel_id);
__be32 tunid_last = tunnel_id_to_key32(v_last->tinfo.tunnel_id);
return (be32_to_cpu(tunid_curr) - be32_to_cpu(tunid_last)) == 1;
}
static int __get_num_vlan_tunnel_infos(struct net_bridge_vlan_group *vg)
{
struct net_bridge_vlan *v, *vtbegin = NULL, *vtend = NULL;
int num_tinfos = 0;
/* Count number of vlan infos */
list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
/* only a context, bridge vlan not activated */
if (!br_vlan_should_use(v) || !v->tinfo.tunnel_id)
continue;
if (!vtbegin) {
goto initvars;
} else if ((v->vid - vtend->vid) == 1 &&
vlan_tunid_inrange(v, vtend)) {
vtend = v;
continue;
} else {
if ((vtend->vid - vtbegin->vid) > 0)
num_tinfos += 2;
else
num_tinfos += 1;
}
initvars:
vtbegin = v;
vtend = v;
}
if (vtbegin && vtend) {
if ((vtend->vid - vtbegin->vid) > 0)
num_tinfos += 2;
else
num_tinfos += 1;
}
return num_tinfos;
}
int br_get_vlan_tunnel_info_size(struct net_bridge_vlan_group *vg)
{
int num_tinfos;
if (!vg)
return 0;
rcu_read_lock();
num_tinfos = __get_num_vlan_tunnel_infos(vg);
rcu_read_unlock();
return num_tinfos * __get_vlan_tinfo_size();
}
static int br_fill_vlan_tinfo(struct sk_buff *skb, u16 vid,
__be64 tunnel_id, u16 flags)
{
__be32 tid = tunnel_id_to_key32(tunnel_id);
struct nlattr *tmap;
tmap = nla_nest_start_noflag(skb, IFLA_BRIDGE_VLAN_TUNNEL_INFO);
if (!tmap)
return -EMSGSIZE;
if (nla_put_u32(skb, IFLA_BRIDGE_VLAN_TUNNEL_ID,
be32_to_cpu(tid)))
goto nla_put_failure;
if (nla_put_u16(skb, IFLA_BRIDGE_VLAN_TUNNEL_VID,
vid))
goto nla_put_failure;
if (nla_put_u16(skb, IFLA_BRIDGE_VLAN_TUNNEL_FLAGS,
flags))
goto nla_put_failure;
nla_nest_end(skb, tmap);
return 0;
nla_put_failure:
nla_nest_cancel(skb, tmap);
return -EMSGSIZE;
}
static int br_fill_vlan_tinfo_range(struct sk_buff *skb,
struct net_bridge_vlan *vtbegin,
struct net_bridge_vlan *vtend)
{
int err;
if (vtend && (vtend->vid - vtbegin->vid) > 0) {
/* add range to skb */
err = br_fill_vlan_tinfo(skb, vtbegin->vid,
vtbegin->tinfo.tunnel_id,
BRIDGE_VLAN_INFO_RANGE_BEGIN);
if (err)
return err;
err = br_fill_vlan_tinfo(skb, vtend->vid,
vtend->tinfo.tunnel_id,
BRIDGE_VLAN_INFO_RANGE_END);
if (err)
return err;
} else {
err = br_fill_vlan_tinfo(skb, vtbegin->vid,
vtbegin->tinfo.tunnel_id,
0);
if (err)
return err;
}
return 0;
}
int br_fill_vlan_tunnel_info(struct sk_buff *skb,
struct net_bridge_vlan_group *vg)
{
struct net_bridge_vlan *vtbegin = NULL;
struct net_bridge_vlan *vtend = NULL;
struct net_bridge_vlan *v;
int err;
/* Count number of vlan infos */
list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
/* only a context, bridge vlan not activated */
if (!br_vlan_should_use(v))
continue;
if (!v->tinfo.tunnel_dst)
continue;
if (!vtbegin) {
goto initvars;
} else if ((v->vid - vtend->vid) == 1 &&
vlan_tunid_inrange(v, vtend)) {
vtend = v;
continue;
} else {
err = br_fill_vlan_tinfo_range(skb, vtbegin, vtend);
if (err)
return err;
}
initvars:
vtbegin = v;
vtend = v;
}
if (vtbegin) {
err = br_fill_vlan_tinfo_range(skb, vtbegin, vtend);
if (err)
return err;
}
return 0;
}
static const struct nla_policy vlan_tunnel_policy[IFLA_BRIDGE_VLAN_TUNNEL_MAX + 1] = {
[IFLA_BRIDGE_VLAN_TUNNEL_ID] = { .type = NLA_U32 },
[IFLA_BRIDGE_VLAN_TUNNEL_VID] = { .type = NLA_U16 },
[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS] = { .type = NLA_U16 },
};
static int br_vlan_tunnel_info(struct net_bridge_port *p, int cmd,
u16 vid, u32 tun_id, bool *changed)
{
int err = 0;
if (!p)
return -EINVAL;
switch (cmd) {
case RTM_SETLINK:
err = nbp_vlan_tunnel_info_add(p, vid, tun_id);
if (!err)
*changed = true;
break;
case RTM_DELLINK:
if (!nbp_vlan_tunnel_info_delete(p, vid))
*changed = true;
break;
}
return err;
}
int br_parse_vlan_tunnel_info(struct nlattr *attr,
struct vtunnel_info *tinfo)
{
struct nlattr *tb[IFLA_BRIDGE_VLAN_TUNNEL_MAX + 1];
u32 tun_id;
u16 vid, flags = 0;
int err;
memset(tinfo, 0, sizeof(*tinfo));
err = nla_parse_nested_deprecated(tb, IFLA_BRIDGE_VLAN_TUNNEL_MAX,
attr, vlan_tunnel_policy, NULL);
if (err < 0)
return err;
if (!tb[IFLA_BRIDGE_VLAN_TUNNEL_ID] ||
!tb[IFLA_BRIDGE_VLAN_TUNNEL_VID])
return -EINVAL;
tun_id = nla_get_u32(tb[IFLA_BRIDGE_VLAN_TUNNEL_ID]);
vid = nla_get_u16(tb[IFLA_BRIDGE_VLAN_TUNNEL_VID]);
if (vid >= VLAN_VID_MASK)
return -ERANGE;
if (tb[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS])
flags = nla_get_u16(tb[IFLA_BRIDGE_VLAN_TUNNEL_FLAGS]);
tinfo->tunid = tun_id;
tinfo->vid = vid;
tinfo->flags = flags;
return 0;
}
int br_process_vlan_tunnel_info(struct net_bridge *br,
struct net_bridge_port *p, int cmd,
struct vtunnel_info *tinfo_curr,
struct vtunnel_info *tinfo_last,
bool *changed)
{
int err;
if (tinfo_curr->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN) {
if (tinfo_last->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN)
return -EINVAL;
memcpy(tinfo_last, tinfo_curr, sizeof(struct vtunnel_info));
} else if (tinfo_curr->flags & BRIDGE_VLAN_INFO_RANGE_END) {
int t, v;
if (!(tinfo_last->flags & BRIDGE_VLAN_INFO_RANGE_BEGIN))
return -EINVAL;
if ((tinfo_curr->vid - tinfo_last->vid) !=
(tinfo_curr->tunid - tinfo_last->tunid))
return -EINVAL;
t = tinfo_last->tunid;
for (v = tinfo_last->vid; v <= tinfo_curr->vid; v++) {
err = br_vlan_tunnel_info(p, cmd, v, t, changed);
if (err)
return err;
t++;
}
memset(tinfo_last, 0, sizeof(struct vtunnel_info));
memset(tinfo_curr, 0, sizeof(struct vtunnel_info));
} else {
if (tinfo_last->flags)
return -EINVAL;
err = br_vlan_tunnel_info(p, cmd, tinfo_curr->vid,
tinfo_curr->tunid, changed);
if (err)
return err;
memset(tinfo_last, 0, sizeof(struct vtunnel_info));
memset(tinfo_curr, 0, sizeof(struct vtunnel_info));
}
return 0;
}
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