linux/net/bridge/br_switchdev.c
Roopa Prabhu ef9a5a62c6 bridge: check for null fdb->dst before notifying switchdev drivers
current switchdev drivers dont seem to support offloading fdb
entries pointing to the bridge device which have fdb->dst
not set to any port. This patch adds a NULL fdb->dst check in
the switchdev notifier code.

This patch fixes the below NULL ptr dereference:
$bridge fdb add 00:02:00:00:00:33 dev br0 self

[   69.953374] BUG: unable to handle kernel NULL pointer dereference at
0000000000000008
[   69.954044] IP: br_switchdev_fdb_notify+0x29/0x80
[   69.954044] PGD 66527067
[   69.954044] P4D 66527067
[   69.954044] PUD 7899c067
[   69.954044] PMD 0
[   69.954044]
[   69.954044] Oops: 0000 [#1] SMP
[   69.954044] Modules linked in:
[   69.954044] CPU: 1 PID: 3074 Comm: bridge Not tainted 4.13.0-rc6+ #1
[   69.954044] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org
04/01/2014
[   69.954044] task: ffff88007b827140 task.stack: ffffc90001564000
[   69.954044] RIP: 0010:br_switchdev_fdb_notify+0x29/0x80
[   69.954044] RSP: 0018:ffffc90001567918 EFLAGS: 00010246
[   69.954044] RAX: 0000000000000000 RBX: ffff8800795e0880 RCX:
00000000000000c0
[   69.954044] RDX: ffffc90001567920 RSI: 000000000000001c RDI:
ffff8800795d0600
[   69.954044] RBP: ffffc90001567938 R08: ffff8800795d0600 R09:
0000000000000000
[   69.954044] R10: ffffc90001567a88 R11: ffff88007b849400 R12:
ffff8800795e0880
[   69.954044] R13: ffff8800795d0600 R14: ffffffff81ef8880 R15:
000000000000001c
[   69.954044] FS:  00007f93d3085700(0000) GS:ffff88007fd00000(0000)
knlGS:0000000000000000
[   69.954044] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   69.954044] CR2: 0000000000000008 CR3: 0000000066551000 CR4:
00000000000006e0
[   69.954044] Call Trace:
[   69.954044]  fdb_notify+0x3f/0xf0
[   69.954044]  __br_fdb_add.isra.12+0x1a7/0x370
[   69.954044]  br_fdb_add+0x178/0x280
[   69.954044]  rtnl_fdb_add+0x10a/0x200
[   69.954044]  rtnetlink_rcv_msg+0x1b4/0x240
[   69.954044]  ? skb_free_head+0x21/0x40
[   69.954044]  ? rtnl_calcit.isra.18+0xf0/0xf0
[   69.954044]  netlink_rcv_skb+0xed/0x120
[   69.954044]  rtnetlink_rcv+0x15/0x20
[   69.954044]  netlink_unicast+0x180/0x200
[   69.954044]  netlink_sendmsg+0x291/0x370
[   69.954044]  ___sys_sendmsg+0x180/0x2e0
[   69.954044]  ? filemap_map_pages+0x2db/0x370
[   69.954044]  ? do_wp_page+0x11d/0x420
[   69.954044]  ? __handle_mm_fault+0x794/0xd80
[   69.954044]  ? vma_link+0xcb/0xd0
[   69.954044]  __sys_sendmsg+0x4c/0x90
[   69.954044]  SyS_sendmsg+0x12/0x20
[   69.954044]  do_syscall_64+0x63/0xe0
[   69.954044]  entry_SYSCALL64_slow_path+0x25/0x25
[   69.954044] RIP: 0033:0x7f93d2bad690
[   69.954044] RSP: 002b:00007ffc7217a638 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[   69.954044] RAX: ffffffffffffffda RBX: 00007ffc72182eac RCX:
00007f93d2bad690
[   69.954044] RDX: 0000000000000000 RSI: 00007ffc7217a670 RDI:
0000000000000003
[   69.954044] RBP: 0000000059a1f7f8 R08: 0000000000000006 R09:
000000000000000a
[   69.954044] R10: 00007ffc7217a400 R11: 0000000000000246 R12:
00007ffc7217a670
[   69.954044] R13: 00007ffc72182a98 R14: 00000000006114c0 R15:
00007ffc72182aa0
[   69.954044] Code: 1f 00 66 66 66 66 90 55 48 89 e5 48 83 ec 20 f6 47
20 04 74 0a 83 fe 1c 74 09 83 fe 1d 74 2c c9 66 90 c3 48 8b 47 10 48 8d
55 e8 <48> 8b 70 08 0f b7 47 1e 48 83 c7 18 48 89 7d f0 bf 03 00 00 00
[   69.954044] RIP: br_switchdev_fdb_notify+0x29/0x80 RSP:
ffffc90001567918
[   69.954044] CR2: 0000000000000008
[   69.954044] ---[ end trace 03e9eec4a82c238b ]---

Fixes: 6b26b51b1d ("net: bridge: Add support for notifying devices about FDB add/del")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28 16:14:00 -07:00

134 lines
3.1 KiB
C

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <net/switchdev.h>
#include "br_private.h"
static int br_switchdev_mark_get(struct net_bridge *br, struct net_device *dev)
{
struct net_bridge_port *p;
/* dev is yet to be added to the port list. */
list_for_each_entry(p, &br->port_list, list) {
if (switchdev_port_same_parent_id(dev, p->dev))
return p->offload_fwd_mark;
}
return ++br->offload_fwd_mark;
}
int nbp_switchdev_mark_set(struct net_bridge_port *p)
{
struct switchdev_attr attr = {
.orig_dev = p->dev,
.id = SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
};
int err;
ASSERT_RTNL();
err = switchdev_port_attr_get(p->dev, &attr);
if (err) {
if (err == -EOPNOTSUPP)
return 0;
return err;
}
p->offload_fwd_mark = br_switchdev_mark_get(p->br, p->dev);
return 0;
}
void nbp_switchdev_frame_mark(const struct net_bridge_port *p,
struct sk_buff *skb)
{
if (skb->offload_fwd_mark && !WARN_ON_ONCE(!p->offload_fwd_mark))
BR_INPUT_SKB_CB(skb)->offload_fwd_mark = p->offload_fwd_mark;
}
bool nbp_switchdev_allowed_egress(const struct net_bridge_port *p,
const struct sk_buff *skb)
{
return !skb->offload_fwd_mark ||
BR_INPUT_SKB_CB(skb)->offload_fwd_mark != p->offload_fwd_mark;
}
/* Flags that can be offloaded to hardware */
#define BR_PORT_FLAGS_HW_OFFLOAD (BR_LEARNING | BR_FLOOD | \
BR_MCAST_FLOOD | BR_BCAST_FLOOD)
int br_switchdev_set_port_flag(struct net_bridge_port *p,
unsigned long flags,
unsigned long mask)
{
struct switchdev_attr attr = {
.orig_dev = p->dev,
.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS_SUPPORT,
};
int err;
if (mask & ~BR_PORT_FLAGS_HW_OFFLOAD)
return 0;
err = switchdev_port_attr_get(p->dev, &attr);
if (err == -EOPNOTSUPP)
return 0;
if (err)
return err;
/* Check if specific bridge flag attribute offload is supported */
if (!(attr.u.brport_flags_support & mask)) {
br_warn(p->br, "bridge flag offload is not supported %u(%s)\n",
(unsigned int)p->port_no, p->dev->name);
return -EOPNOTSUPP;
}
attr.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS;
attr.flags = SWITCHDEV_F_DEFER;
attr.u.brport_flags = flags;
err = switchdev_port_attr_set(p->dev, &attr);
if (err) {
br_warn(p->br, "error setting offload flag on port %u(%s)\n",
(unsigned int)p->port_no, p->dev->name);
return err;
}
return 0;
}
static void
br_switchdev_fdb_call_notifiers(bool adding, const unsigned char *mac,
u16 vid, struct net_device *dev)
{
struct switchdev_notifier_fdb_info info;
unsigned long notifier_type;
info.addr = mac;
info.vid = vid;
notifier_type = adding ? SWITCHDEV_FDB_ADD_TO_DEVICE : SWITCHDEV_FDB_DEL_TO_DEVICE;
call_switchdev_notifiers(notifier_type, dev, &info.info);
}
void
br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
{
if (!fdb->added_by_user || !fdb->dst)
return;
switch (type) {
case RTM_DELNEIGH:
br_switchdev_fdb_call_notifiers(false, fdb->addr.addr,
fdb->vlan_id,
fdb->dst->dev);
break;
case RTM_NEWNEIGH:
br_switchdev_fdb_call_notifiers(true, fdb->addr.addr,
fdb->vlan_id,
fdb->dst->dev);
break;
}
}