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can: raw: fix ro->uniq use-after-free in raw_rcv()

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raw_release() unregisters raw CAN receive filters via can_rx_unregister(),
but receiver deletion is deferred with call_rcu(). This leaves a window
where raw_rcv() may still be running in an RCU read-side critical section
after raw_release() frees ro->uniq, leading to a use-after-free of the
percpu uniq storage.

Move free_percpu(ro->uniq) out of raw_release() and into a raw-specific
socket destructor. can_rx_unregister() takes an extra reference to the
socket and only drops it from the RCU callback, so freeing uniq from
sk_destruct ensures the percpu area is not released until the relevant
callbacks have drained.

Fixes: 514ac99c64 ("can: fix multiple delivery of a single CAN frame for overlapping CAN filters")
Cc: stable@vger.kernel.org # v4.1+
Assisted-by: Bynario AI
Signed-off-by: Samuel Page <sam@bynar.io>
Link: https://patch.msgid.link/26ec626d-cae7-4418-9782-7198864d070c@bynar.io
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
[mkl: applied manually]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Samuel Page
2026-04-08 15:30:13 +01:00
committed by Marc Kleine-Budde
parent fed4626501
commit a535a9217c
1 changed files with 10 additions and 1 deletions
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11
net/can/raw.c
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@@ -361,6 +361,14 @@ static int raw_notifier(struct notifier_block *nb, unsigned long msg,
return NOTIFY_DONE;
}
static void raw_sock_destruct(struct sock *sk)
{
struct raw_sock *ro = raw_sk(sk);
free_percpu(ro->uniq);
can_sock_destruct(sk);
}
static int raw_init(struct sock *sk)
{
struct raw_sock *ro = raw_sk(sk);
@@ -387,6 +395,8 @@ static int raw_init(struct sock *sk)
if (unlikely(!ro->uniq))
return -ENOMEM;
sk->sk_destruct = raw_sock_destruct;
/* set notifier */
spin_lock(&raw_notifier_lock);
list_add_tail(&ro->notifier, &raw_notifier_list);
@@ -436,7 +446,6 @@ static int raw_release(struct socket *sock)
ro->bound = 0;
ro->dev = NULL;
ro->count = 0;
free_percpu(ro->uniq);
sock_orphan(sk);
sock->sk = NULL;