6.1-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Hartkopp socketcan@hartkopp.net
commit c275a176e4b69868576e543409927ae75e3a3288 upstream.
Commit ee8b94c8510c ("can: raw: fix receiver memory leak") introduced a new reference to the CAN netdevice that has assigned CAN filters. But this new ro->dev reference did not maintain its own refcount which lead to another KASAN use-after-free splat found by Eric Dumazet.
This patch ensures a proper refcount for the CAN nedevice.
Fixes: ee8b94c8510c ("can: raw: fix receiver memory leak") Reported-by: Eric Dumazet edumazet@google.com Cc: Ziyang Xuan william.xuanziyang@huawei.com Signed-off-by: Oliver Hartkopp socketcan@hartkopp.net Link: https://lore.kernel.org/r/20230821144547.6658-3-socketcan@hartkopp.net Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/can/raw.c | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-)
--- a/net/can/raw.c +++ b/net/can/raw.c @@ -85,6 +85,7 @@ struct raw_sock { int bound; int ifindex; struct net_device *dev; + netdevice_tracker dev_tracker; struct list_head notifier; int loopback; int recv_own_msgs; @@ -285,8 +286,10 @@ static void raw_notify(struct raw_sock * case NETDEV_UNREGISTER: lock_sock(sk); /* remove current filters & unregister */ - if (ro->bound) + if (ro->bound) { raw_disable_allfilters(dev_net(dev), dev, sk); + netdev_put(dev, &ro->dev_tracker); + }
if (ro->count > 1) kfree(ro->filter); @@ -391,10 +394,12 @@ static int raw_release(struct socket *so
/* remove current filters & unregister */ if (ro->bound) { - if (ro->dev) + if (ro->dev) { raw_disable_allfilters(dev_net(ro->dev), ro->dev, sk); - else + netdev_put(ro->dev, &ro->dev_tracker); + } else { raw_disable_allfilters(sock_net(sk), NULL, sk); + } }
if (ro->count > 1) @@ -445,10 +450,10 @@ static int raw_bind(struct socket *sock, goto out; } if (dev->type != ARPHRD_CAN) { - dev_put(dev); err = -ENODEV; - goto out; + goto out_put_dev; } + if (!(dev->flags & IFF_UP)) notify_enetdown = 1;
@@ -456,7 +461,9 @@ static int raw_bind(struct socket *sock,
/* filters set by default/setsockopt */ err = raw_enable_allfilters(sock_net(sk), dev, sk); - dev_put(dev); + if (err) + goto out_put_dev; + } else { ifindex = 0;
@@ -467,18 +474,28 @@ static int raw_bind(struct socket *sock, if (!err) { if (ro->bound) { /* unregister old filters */ - if (ro->dev) + if (ro->dev) { raw_disable_allfilters(dev_net(ro->dev), ro->dev, sk); - else + /* drop reference to old ro->dev */ + netdev_put(ro->dev, &ro->dev_tracker); + } else { raw_disable_allfilters(sock_net(sk), NULL, sk); + } } ro->ifindex = ifindex; ro->bound = 1; + /* bind() ok -> hold a reference for new ro->dev */ ro->dev = dev; + if (ro->dev) + netdev_hold(ro->dev, &ro->dev_tracker, GFP_KERNEL); }
- out: +out_put_dev: + /* remove potential reference from dev_get_by_index() */ + if (dev) + dev_put(dev); +out: release_sock(sk); rtnl_unlock();