From 0ce1822c2a08f6e05e22239bcb1778dcc916c7bc Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Mon, 21 Oct 2019 18:47:57 +0000 Subject: vxlan: add adjacent link to limit depth level Current vxlan code doesn't limit the number of nested devices. Nested devices would be handled recursively and this routine needs huge stack memory. So, unlimited nested devices could make stack overflow. In order to fix this issue, this patch adds adjacent links. The adjacent link APIs internally check the depth level. Test commands: ip link add dummy0 type dummy ip link add vxlan0 type vxlan id 0 group 239.1.1.1 dev dummy0 \ dstport 4789 for i in {1..100} do let A=$i-1 ip link add vxlan$i type vxlan id $i group 239.1.1.1 \ dev vxlan$A dstport 4789 done ip link del dummy0 The top upper link is vxlan100 and the lowest link is vxlan0. When vxlan0 is deleting, the upper devices will be deleted recursively. It needs huge stack memory so it makes stack overflow. Splat looks like: [ 229.628477] ============================================================================= [ 229.629785] BUG page->ptl (Not tainted): Padding overwritten. 0x0000000026abf214-0x0000000091f6abb2 [ 229.629785] ----------------------------------------------------------------------------- [ 229.629785] [ 229.655439] ================================================================== [ 229.629785] INFO: Slab 0x00000000ff7cfda8 objects=19 used=19 fp=0x00000000fe33776c flags=0x200000000010200 [ 229.655688] BUG: KASAN: stack-out-of-bounds in unmap_single_vma+0x25a/0x2e0 [ 229.655688] Read of size 8 at addr ffff888113076928 by task vlan-network-in/2334 [ 229.655688] [ 229.629785] Padding 0000000026abf214: 00 80 14 0d 81 88 ff ff 68 91 81 14 81 88 ff ff ........h....... [ 229.629785] Padding 0000000001e24790: 38 91 81 14 81 88 ff ff 68 91 81 14 81 88 ff ff 8.......h....... [ 229.629785] Padding 00000000b39397c8: 33 30 62 a7 ff ff ff ff ff eb 60 22 10 f1 ff 1f 30b.......`".... [ 229.629785] Padding 00000000bc98f53a: 80 60 07 13 81 88 ff ff 00 80 14 0d 81 88 ff ff .`.............. [ 229.629785] Padding 000000002aa8123d: 68 91 81 14 81 88 ff ff f7 21 17 a7 ff ff ff ff h........!...... [ 229.629785] Padding 000000001c8c2369: 08 81 14 0d 81 88 ff ff 03 02 00 00 00 00 00 00 ................ [ 229.629785] Padding 000000004e290c5d: 21 90 a2 21 10 ed ff ff 00 00 00 00 00 fc ff df !..!............ [ 229.629785] Padding 000000000e25d731: 18 60 07 13 81 88 ff ff c0 8b 13 05 81 88 ff ff .`.............. [ 229.629785] Padding 000000007adc7ab3: b3 8a b5 41 00 00 00 00 ...A.... [ 229.629785] FIX page->ptl: Restoring 0x0000000026abf214-0x0000000091f6abb2=0x5a [ ... ] Fixes: acaf4e70997f ("net: vxlan: when lower dev unregisters remove vxlan dev as well") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 53 +++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 10 deletions(-) (limited to 'drivers/net/vxlan.c') diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 3d9bcc957f7d..fcf028220bca 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3566,10 +3566,13 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev, { struct vxlan_net *vn = net_generic(net, vxlan_net_id); struct vxlan_dev *vxlan = netdev_priv(dev); + struct net_device *remote_dev = NULL; struct vxlan_fdb *f = NULL; bool unregister = false; + struct vxlan_rdst *dst; int err; + dst = &vxlan->default_dst; err = vxlan_dev_configure(net, dev, conf, false, extack); if (err) return err; @@ -3577,14 +3580,14 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev, dev->ethtool_ops = &vxlan_ethtool_ops; /* create an fdb entry for a valid default destination */ - if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) { + if (!vxlan_addr_any(&dst->remote_ip)) { err = vxlan_fdb_create(vxlan, all_zeros_mac, - &vxlan->default_dst.remote_ip, + &dst->remote_ip, NUD_REACHABLE | NUD_PERMANENT, vxlan->cfg.dst_port, - vxlan->default_dst.remote_vni, - vxlan->default_dst.remote_vni, - vxlan->default_dst.remote_ifindex, + dst->remote_vni, + dst->remote_vni, + dst->remote_ifindex, NTF_SELF, &f); if (err) return err; @@ -3595,26 +3598,41 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev, goto errout; unregister = true; + if (dst->remote_ifindex) { + remote_dev = __dev_get_by_index(net, dst->remote_ifindex); + if (!remote_dev) + goto errout; + + err = netdev_upper_dev_link(remote_dev, dev, extack); + if (err) + goto errout; + } + err = rtnl_configure_link(dev, NULL); if (err) - goto errout; + goto unlink; if (f) { - vxlan_fdb_insert(vxlan, all_zeros_mac, - vxlan->default_dst.remote_vni, f); + vxlan_fdb_insert(vxlan, all_zeros_mac, dst->remote_vni, f); /* notify default fdb entry */ err = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f), RTM_NEWNEIGH, true, extack); if (err) { vxlan_fdb_destroy(vxlan, f, false, false); + if (remote_dev) + netdev_upper_dev_unlink(remote_dev, dev); goto unregister; } } list_add(&vxlan->next, &vn->vxlan_list); + if (remote_dev) + dst->remote_dev = remote_dev; return 0; - +unlink: + if (remote_dev) + netdev_upper_dev_unlink(remote_dev, dev); errout: /* unregister_netdevice() destroys the default FDB entry with deletion * notification. But the addition notification was not sent yet, so @@ -3932,11 +3950,12 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], struct netlink_ext_ack *extack) { struct vxlan_dev *vxlan = netdev_priv(dev); - struct vxlan_rdst *dst = &vxlan->default_dst; struct net_device *lowerdev; struct vxlan_config conf; + struct vxlan_rdst *dst; int err; + dst = &vxlan->default_dst; err = vxlan_nl2conf(tb, data, dev, &conf, true, extack); if (err) return err; @@ -3946,6 +3965,11 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], if (err) return err; + err = netdev_adjacent_change_prepare(dst->remote_dev, lowerdev, dev, + extack); + if (err) + return err; + /* handle default dst entry */ if (!vxlan_addr_equal(&conf.remote_ip, &dst->remote_ip)) { u32 hash_index = fdb_head_index(vxlan, all_zeros_mac, conf.vni); @@ -3962,6 +3986,8 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], NTF_SELF, true, extack); if (err) { spin_unlock_bh(&vxlan->hash_lock[hash_index]); + netdev_adjacent_change_abort(dst->remote_dev, + lowerdev, dev); return err; } } @@ -3979,6 +4005,11 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], if (conf.age_interval != vxlan->cfg.age_interval) mod_timer(&vxlan->age_timer, jiffies); + netdev_adjacent_change_commit(dst->remote_dev, lowerdev, dev); + if (lowerdev && lowerdev != dst->remote_dev) + dst->remote_dev = lowerdev; + + netdev_update_lockdep_key(lowerdev); vxlan_config_apply(dev, &conf, lowerdev, vxlan->net, true); return 0; } @@ -3991,6 +4022,8 @@ static void vxlan_dellink(struct net_device *dev, struct list_head *head) list_del(&vxlan->next); unregister_netdevice_queue(dev, head); + if (vxlan->default_dst.remote_dev) + netdev_upper_dev_unlink(vxlan->default_dst.remote_dev, dev); } static size_t vxlan_get_size(const struct net_device *dev) -- cgit v1.2.3 From eadf52cf1852196a1363044dcda22fa5d7f296f7 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Tue, 29 Oct 2019 01:24:32 +0800 Subject: vxlan: check tun_info options_len properly This patch is to improve the tun_info options_len by dropping the skb when TUNNEL_VXLAN_OPT is set but options_len is less than vxlan_metadata. This can void a potential out-of-bounds access on ip_tun_info. Fixes: ee122c79d422 ("vxlan: Flow based tunneling") Signed-off-by: Xin Long Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/net/vxlan.c') diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index fcf028220bca..ac5c597aa703 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2487,9 +2487,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, vni = tunnel_id_to_key32(info->key.tun_id); ifindex = 0; dst_cache = &info->dst_cache; - if (info->options_len && - info->key.tun_flags & TUNNEL_VXLAN_OPT) + if (info->key.tun_flags & TUNNEL_VXLAN_OPT) { + if (info->options_len < sizeof(*md)) + goto drop; md = ip_tunnel_info_opts(info); + } ttl = info->key.ttl; tos = info->key.tos; label = info->key.label; -- cgit v1.2.3 From c6761cf521f9bffbdcbb619dba665ebf3bcefb1e Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Wed, 30 Oct 2019 08:15:12 +0000 Subject: vxlan: fix unexpected failure of vxlan_changelink() After commit 0ce1822c2a08 ("vxlan: add adjacent link to limit depth level"), vxlan_changelink() could fail because of netdev_adjacent_change_prepare(). netdev_adjacent_change_prepare() returns -EEXIST when old lower device and new lower device are same. (old lower device is "dst->remote_dev" and new lower device is "lowerdev") So, before calling it, lowerdev should be NULL if these devices are same. Test command1: ip link add dummy0 type dummy ip link add vxlan0 type vxlan dev dummy0 dstport 4789 vni 1 ip link set vxlan0 type vxlan ttl 5 RTNETLINK answers: File exists Reported-by: Dan Carpenter Fixes: 0ce1822c2a08 ("vxlan: add adjacent link to limit depth level") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'drivers/net/vxlan.c') diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index ac5c597aa703..8869154fad88 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3967,6 +3967,9 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], if (err) return err; + if (dst->remote_dev == lowerdev) + lowerdev = NULL; + err = netdev_adjacent_change_prepare(dst->remote_dev, lowerdev, dev, extack); if (err) @@ -4008,10 +4011,10 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], mod_timer(&vxlan->age_timer, jiffies); netdev_adjacent_change_commit(dst->remote_dev, lowerdev, dev); - if (lowerdev && lowerdev != dst->remote_dev) + if (lowerdev && lowerdev != dst->remote_dev) { dst->remote_dev = lowerdev; - - netdev_update_lockdep_key(lowerdev); + netdev_update_lockdep_key(lowerdev); + } vxlan_config_apply(dev, &conf, lowerdev, vxlan->net, true); return 0; } -- cgit v1.2.3