FAILED: patch "[PATCH] can: raw: add missing refcount for memory leak fix" failed to apply to 5.15-stable tree

gregkh
2023-08-27T10:33:33Z

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x c275a176e4b69868576e543409927ae75e3a3288
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082737-cavity-bloating-1779@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

c275a176e4b6 ("can: raw: add missing refcount for memory leak fix")
ee8b94c8510c ("can: raw: fix receiver memory leak")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c275a176e4b69868576e543409927ae75e3a3288 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Mon, 21 Aug 2023 16:45:47 +0200
Subject: [PATCH] can: raw: add missing refcount for memory leak fix

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>

diff --git a/net/can/raw.c b/net/can/raw.c
index e10f59375659..d50c3f3d892f 100644
--- 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 *ro, unsigned long msg,
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 *sock)

/* 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, struct sockaddr *uaddr, int len)
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, struct sockaddr *uaddr, int len)

/* 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, struct sockaddr *uaddr, int len)
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();