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can: raw: fix receiver memory leak
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Got kmemleak errors with the following ltp can_filter testcase:

for ((i=1; i<=100; i++))
do
        ./can_filter &
        sleep 0.1
done

==============================================================
[<00000000db4a4943>] can_rx_register+0x147/0x360 [can]
[<00000000a289549d>] raw_setsockopt+0x5ef/0x853 [can_raw]
[<000000006d3d9ebd>] __sys_setsockopt+0x173/0x2c0
[<00000000407dbfec>] __x64_sys_setsockopt+0x61/0x70
[<00000000fd468496>] do_syscall_64+0x33/0x40
[<00000000b7e47d51>] entry_SYSCALL_64_after_hwframe+0x61/0xc6

It's a bug in the concurrent scenario of unregister_netdevice_many()
and raw_release() as following:

             cpu0                                        cpu1
unregister_netdevice_many(can_dev)
  unlist_netdevice(can_dev) // dev_get_by_index() return NULL after this
  net_set_todo(can_dev)
						raw_release(can_socket)
						  dev = dev_get_by_index(, ro->ifindex); // dev == NULL
						  if (dev) { // receivers in dev_rcv_lists not free because dev is NULL
						    raw_disable_allfilters(, dev, );
						    dev_put(dev);
						  }
						  ...
						  ro->bound = 0;
						  ...

call_netdevice_notifiers(NETDEV_UNREGISTER, )
  raw_notify(, NETDEV_UNREGISTER, )
    if (ro->bound) // invalid because ro->bound has been set 0
      raw_disable_allfilters(, dev, ); // receivers in dev_rcv_lists will never be freed

Add a net_device pointer member in struct raw_sock to record bound
can_dev, and use rtnl_lock to serialize raw_socket members between
raw_bind(), raw_release(), raw_setsockopt() and raw_notify(). Use
ro->dev to decide whether to free receivers in dev_rcv_lists.

Fixes: 8d0caed ("can: bcm/raw/isotp: use per module netdevice notifier")
Reviewed-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Link: https://lore.kernel.org/all/20230711011737.1969582-1-william.xuanziyang@huawei.com
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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@marckleinebudde
Ziyang Xuan authored and marckleinebudde committed Jul 17, 2023
1 parent 0dd1805 commit ee8b94c
Showing 1 changed file with 24 additions and 33 deletions.
57 changes: 24 additions & 33 deletions net/can/raw.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,7 @@ struct raw_sock {
struct sock sk;
int bound;
int ifindex;
struct net_device *dev;
struct list_head notifier;
int loopback;
int recv_own_msgs;
Expand Down Expand Up @@ -277,7 +278,7 @@ static void raw_notify(struct raw_sock *ro, unsigned long msg,
if (!net_eq(dev_net(dev), sock_net(sk)))
return;

if (ro->ifindex != dev->ifindex)
if (ro->dev != dev)
return;

switch (msg) {
Expand All @@ -292,6 +293,7 @@ static void raw_notify(struct raw_sock *ro, unsigned long msg,

ro->ifindex = 0;
ro->bound = 0;
ro->dev = NULL;
ro->count = 0;
release_sock(sk);

Expand Down Expand Up @@ -337,6 +339,7 @@ static int raw_init(struct sock *sk)

ro->bound = 0;
ro->ifindex = 0;
ro->dev = NULL;

/* set default filter to single entry dfilter */
ro->dfilter.can_id = 0;
Expand Down Expand Up @@ -385,28 +388,24 @@ static int raw_release(struct socket *sock)

lock_sock(sk);

rtnl_lock();
/* remove current filters & unregister */
if (ro->bound) {
if (ro->ifindex) {
struct net_device *dev;

dev = dev_get_by_index(sock_net(sk), ro->ifindex);
if (dev) {
raw_disable_allfilters(dev_net(dev), dev, sk);
dev_put(dev);
}
} else {
if (ro->dev)
raw_disable_allfilters(dev_net(ro->dev), ro->dev, sk);
else
raw_disable_allfilters(sock_net(sk), NULL, sk);
}
}

if (ro->count > 1)
kfree(ro->filter);

ro->ifindex = 0;
ro->bound = 0;
ro->dev = NULL;
ro->count = 0;
free_percpu(ro->uniq);
rtnl_unlock();

sock_orphan(sk);
sock->sk = NULL;
Expand All @@ -422,6 +421,7 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
struct sock *sk = sock->sk;
struct raw_sock *ro = raw_sk(sk);
struct net_device *dev = NULL;
int ifindex;
int err = 0;
int notify_enetdown = 0;
Expand All @@ -431,14 +431,13 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (addr->can_family != AF_CAN)
return -EINVAL;

rtnl_lock();
lock_sock(sk);

if (ro->bound && addr->can_ifindex == ro->ifindex)
goto out;

if (addr->can_ifindex) {
struct net_device *dev;

dev = dev_get_by_index(sock_net(sk), addr->can_ifindex);
if (!dev) {
err = -ENODEV;
Expand Down Expand Up @@ -467,26 +466,20 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (!err) {
if (ro->bound) {
/* unregister old filters */
if (ro->ifindex) {
struct net_device *dev;

dev = dev_get_by_index(sock_net(sk),
ro->ifindex);
if (dev) {
raw_disable_allfilters(dev_net(dev),
dev, sk);
dev_put(dev);
}
} else {
if (ro->dev)
raw_disable_allfilters(dev_net(ro->dev),
ro->dev, sk);
else
raw_disable_allfilters(sock_net(sk), NULL, sk);
}
}
ro->ifindex = ifindex;
ro->bound = 1;
ro->dev = dev;
}

out:
release_sock(sk);
rtnl_unlock();

if (notify_enetdown) {
sk->sk_err = ENETDOWN;
Expand Down Expand Up @@ -553,9 +546,9 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
rtnl_lock();
lock_sock(sk);

if (ro->bound && ro->ifindex) {
dev = dev_get_by_index(sock_net(sk), ro->ifindex);
if (!dev) {
dev = ro->dev;
if (ro->bound && dev) {
if (dev->reg_state != NETREG_REGISTERED) {
if (count > 1)
kfree(filter);
err = -ENODEV;
Expand Down Expand Up @@ -596,7 +589,6 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
ro->count = count;

out_fil:
dev_put(dev);
release_sock(sk);
rtnl_unlock();

Expand All @@ -614,9 +606,9 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
rtnl_lock();
lock_sock(sk);

if (ro->bound && ro->ifindex) {
dev = dev_get_by_index(sock_net(sk), ro->ifindex);
if (!dev) {
dev = ro->dev;
if (ro->bound && dev) {
if (dev->reg_state != NETREG_REGISTERED) {
err = -ENODEV;
goto out_err;
}
Expand All @@ -640,7 +632,6 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
ro->err_mask = err_mask;

out_err:
dev_put(dev);
release_sock(sk);
rtnl_unlock();

Expand Down

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