Revision 9c1c2b35f1d94de8325344c2777d7ee67492db3b authored by Jeff Layton on 03 April 2019, 17:16:01 UTC, committed by Ilya Dryomov on 21 January 2020, 18:02:37 UTC
Currently, we just assume that it will stick around by virtue of the submitter's reference, but later patches will allow the syscall to return early and we can't rely on that reference at that point. While I'm not aware of any reports of it, Xiubo pointed out that this may fix a use-after-free. If the wait for a reply times out or is canceled via signal, and then the reply comes in after the syscall returns, the client can end up trying to access r_parent without a reference. Take an extra reference to the inode when setting r_parent and release it when releasing the request. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
1 parent def9d27
br_netlink_tunnel.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Bridge per vlan tunnel port dst_metadata netlink control interface
*
* Authors:
* Roopa Prabhu <roopa@cumulusnetworks.com>
*/
#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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