From: Ziyang Xuan william.xuanziyang@huawei.com

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: 8d0caedb7596 ("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@huaw... Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- net/can/raw.c | 57 ++++++++++++++++++++++----------------------------- 1 file changed, 24 insertions(+), 33 deletions(-)

diff --git a/net/can/raw.c b/net/can/raw.c index 15c79b079184..2302e4882967 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -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; @@ -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) { @@ -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);

@@ -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; @@ -385,19 +388,13 @@ 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) @@ -405,8 +402,10 @@ static int raw_release(struct socket *sock)

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

sock_orphan(sk); sock->sk = NULL; @@ -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; @@ -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; @@ -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; @@ -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; @@ -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();

@@ -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; } @@ -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();

base-commit: 0dd1805fe498e0cf64f68e451a8baff7e64494ec