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Subject[PATCH 4.19 212/243] xfrm interface: fix memory leak on creation
Date
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

commit 56c5ee1a5823e9cf5288b84ae6364cb4112f8225 upstream.

The following commands produce a backtrace and return an error but the xfrm
interface is created (in the wrong netns):
$ ip netns add foo
$ ip netns add bar
$ ip -n foo netns set bar 0
$ ip -n foo link add xfrmi0 link-netnsid 0 type xfrm dev lo if_id 23
RTNETLINK answers: Invalid argument
$ ip -n bar link ls xfrmi0
2: xfrmi0@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/none 00:00:00:00:00:00 brd 00:00:00:00:00:00

Here is the backtrace:
[ 79.879174] WARNING: CPU: 0 PID: 1178 at net/core/dev.c:8172 rollback_registered_many+0x86/0x3c1
[ 79.880260] Modules linked in: xfrm_interface nfsv3 nfs_acl auth_rpcgss nfsv4 nfs lockd grace sunrpc fscache button parport_pc parport serio_raw evdev pcspkr loop ext4 crc16 mbcache jbd2 crc32c_generic ide_cd_mod ide_gd_mod cdrom ata_$
eneric ata_piix libata scsi_mod 8139too piix psmouse i2c_piix4 ide_core 8139cp mii i2c_core floppy
[ 79.883698] CPU: 0 PID: 1178 Comm: ip Not tainted 5.2.0-rc6+ #106
[ 79.884462] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[ 79.885447] RIP: 0010:rollback_registered_many+0x86/0x3c1
[ 79.886120] Code: 01 e8 d7 7d c6 ff 0f 0b 48 8b 45 00 4c 8b 20 48 8d 58 90 49 83 ec 70 48 8d 7b 70 48 39 ef 74 44 8a 83 d0 04 00 00 84 c0 75 1f <0f> 0b e8 61 cd ff ff 48 b8 00 01 00 00 00 00 ad de 48 89 43 70 66
[ 79.888667] RSP: 0018:ffffc900015ab740 EFLAGS: 00010246
[ 79.889339] RAX: ffff8882353e5700 RBX: ffff8882353e56a0 RCX: ffff8882353e5710
[ 79.890174] RDX: ffffc900015ab7e0 RSI: ffffc900015ab7e0 RDI: ffff8882353e5710
[ 79.891029] RBP: ffffc900015ab7e0 R08: ffffc900015ab7e0 R09: ffffc900015ab7e0
[ 79.891866] R10: ffffc900015ab7a0 R11: ffffffff82233fec R12: ffffc900015ab770
[ 79.892728] R13: ffffffff81eb7ec0 R14: ffff88822ed6cf00 R15: 00000000ffffffea
[ 79.893557] FS: 00007ff350f31740(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000
[ 79.894581] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 79.895317] CR2: 00000000006c8580 CR3: 000000022c272000 CR4: 00000000000006f0
[ 79.896137] Call Trace:
[ 79.896464] unregister_netdevice_many+0x12/0x6c
[ 79.896998] __rtnl_newlink+0x6e2/0x73b
[ 79.897446] ? __kmalloc_node_track_caller+0x15e/0x185
[ 79.898039] ? pskb_expand_head+0x5f/0x1fe
[ 79.898556] ? stack_access_ok+0xd/0x2c
[ 79.899009] ? deref_stack_reg+0x12/0x20
[ 79.899462] ? stack_access_ok+0xd/0x2c
[ 79.899927] ? stack_access_ok+0xd/0x2c
[ 79.900404] ? __module_text_address+0x9/0x4f
[ 79.900910] ? is_bpf_text_address+0x5/0xc
[ 79.901390] ? kernel_text_address+0x67/0x7b
[ 79.901884] ? __kernel_text_address+0x1a/0x25
[ 79.902397] ? unwind_get_return_address+0x12/0x23
[ 79.903122] ? __cmpxchg_double_slab.isra.37+0x46/0x77
[ 79.903772] rtnl_newlink+0x43/0x56
[ 79.904217] rtnetlink_rcv_msg+0x200/0x24c

In fact, each time a xfrm interface was created, a netdev was allocated
by __rtnl_newlink()/rtnl_create_link() and then another one by
xfrmi_newlink()/xfrmi_create(). Only the second one was registered, it's
why the previous commands produce a backtrace: dev_change_net_namespace()
was called on a netdev with reg_state set to NETREG_UNINITIALIZED (the
first one).

CC: Lorenzo Colitti <lorenzo@google.com>
CC: Benedict Wong <benedictwong@google.com>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Shannon Nelson <shannon.nelson@oracle.com>
CC: Antony Antony <antony@phenome.org>
CC: Eyal Birger <eyal.birger@gmail.com>
Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Reported-by: Julien Floret <julien.floret@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/xfrm/xfrm_interface.c | 98 +++++++++++++---------------------------------
1 file changed, 28 insertions(+), 70 deletions(-)

--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -133,7 +133,7 @@ static void xfrmi_dev_free(struct net_de
free_percpu(dev->tstats);
}

-static int xfrmi_create2(struct net_device *dev)
+static int xfrmi_create(struct net_device *dev)
{
struct xfrm_if *xi = netdev_priv(dev);
struct net *net = dev_net(dev);
@@ -156,54 +156,7 @@ out:
return err;
}

-static struct xfrm_if *xfrmi_create(struct net *net, struct xfrm_if_parms *p)
-{
- struct net_device *dev;
- struct xfrm_if *xi;
- char name[IFNAMSIZ];
- int err;
-
- if (p->name[0]) {
- strlcpy(name, p->name, IFNAMSIZ);
- } else {
- err = -EINVAL;
- goto failed;
- }
-
- dev = alloc_netdev(sizeof(*xi), name, NET_NAME_UNKNOWN, xfrmi_dev_setup);
- if (!dev) {
- err = -EAGAIN;
- goto failed;
- }
-
- dev_net_set(dev, net);
-
- xi = netdev_priv(dev);
- xi->p = *p;
- xi->net = net;
- xi->dev = dev;
- xi->phydev = dev_get_by_index(net, p->link);
- if (!xi->phydev) {
- err = -ENODEV;
- goto failed_free;
- }
-
- err = xfrmi_create2(dev);
- if (err < 0)
- goto failed_dev_put;
-
- return xi;
-
-failed_dev_put:
- dev_put(xi->phydev);
-failed_free:
- free_netdev(dev);
-failed:
- return ERR_PTR(err);
-}
-
-static struct xfrm_if *xfrmi_locate(struct net *net, struct xfrm_if_parms *p,
- int create)
+static struct xfrm_if *xfrmi_locate(struct net *net, struct xfrm_if_parms *p)
{
struct xfrm_if __rcu **xip;
struct xfrm_if *xi;
@@ -211,17 +164,11 @@ static struct xfrm_if *xfrmi_locate(stru

for (xip = &xfrmn->xfrmi[0];
(xi = rtnl_dereference(*xip)) != NULL;
- xip = &xi->next) {
- if (xi->p.if_id == p->if_id) {
- if (create)
- return ERR_PTR(-EEXIST);
-
+ xip = &xi->next)
+ if (xi->p.if_id == p->if_id)
return xi;
- }
- }
- if (!create)
- return ERR_PTR(-ENODEV);
- return xfrmi_create(net, p);
+
+ return NULL;
}

static void xfrmi_dev_uninit(struct net_device *dev)
@@ -689,21 +636,33 @@ static int xfrmi_newlink(struct net *src
struct netlink_ext_ack *extack)
{
struct net *net = dev_net(dev);
- struct xfrm_if_parms *p;
+ struct xfrm_if_parms p;
struct xfrm_if *xi;
+ int err;

- xi = netdev_priv(dev);
- p = &xi->p;
-
- xfrmi_netlink_parms(data, p);
+ xfrmi_netlink_parms(data, &p);

if (!tb[IFLA_IFNAME])
return -EINVAL;

- nla_strlcpy(p->name, tb[IFLA_IFNAME], IFNAMSIZ);
+ nla_strlcpy(p.name, tb[IFLA_IFNAME], IFNAMSIZ);

- xi = xfrmi_locate(net, p, 1);
- return PTR_ERR_OR_ZERO(xi);
+ xi = xfrmi_locate(net, &p);
+ if (xi)
+ return -EEXIST;
+
+ xi = netdev_priv(dev);
+ xi->p = p;
+ xi->net = net;
+ xi->dev = dev;
+ xi->phydev = dev_get_by_index(net, p.link);
+ if (!xi->phydev)
+ return -ENODEV;
+
+ err = xfrmi_create(dev);
+ if (err < 0)
+ dev_put(xi->phydev);
+ return err;
}

static void xfrmi_dellink(struct net_device *dev, struct list_head *head)
@@ -720,9 +679,8 @@ static int xfrmi_changelink(struct net_d

xfrmi_netlink_parms(data, &xi->p);

- xi = xfrmi_locate(net, &xi->p, 0);
-
- if (IS_ERR_OR_NULL(xi)) {
+ xi = xfrmi_locate(net, &xi->p);
+ if (!xi) {
xi = netdev_priv(dev);
} else {
if (xi->dev != dev)

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