From: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
[ Upstream commit de8a6b15d9654c3e4f672d76da9d9df8ee06331d ]
Currently, we correlate the mctp_sk_key lifetime to the sock lifetime
through the sock hash/unhash operations, but this is pretty tenuous, and
there are cases where we may have a temporary reference to an unhashed
sk.
This change makes the reference more explicit, by adding a hold on the
sock when it's associated with a mctp_sk_key, released on final key
unref.
Fixes: 73c618456dc5 ("mctp: locking, lifetime and validity changes for sk_keys")
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/mctp/route.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/mctp/route.c b/net/mctp/route.c
index f9a80b82dc51..ce10ba7ae839 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -147,6 +147,7 @@ static struct mctp_sk_key *mctp_key_alloc(struct mctp_sock *msk,
key->valid = true;
spin_lock_init(&key->lock);
refcount_set(&key->refs, 1);
+ sock_hold(key->sk);
return key;
}
@@ -165,6 +166,7 @@ void mctp_key_unref(struct mctp_sk_key *key)
mctp_dev_release_key(key->dev, key);
spin_unlock_irqrestore(&key->lock, flags);
+ sock_put(key->sk);
kfree(key);
}
@@ -419,14 +421,14 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
* this function.
*/
rc = mctp_key_add(key, msk);
- if (rc) {
- kfree(key);
- } else {
+ if (!rc)
trace_mctp_key_acquire(key);
- /* we don't need to release key->lock on exit */
- mctp_key_unref(key);
- }
+ /* we don't need to release key->lock on exit, so
+ * clean up here and suppress the unlock via
+ * setting to NULL
+ */
+ mctp_key_unref(key);
key = NULL;
} else {
--
2.39.0
