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net: mctp: add an explicit reference from a mctp_sk_key to sock

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[ 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@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jeremy Kerr 2023-01-24 10:01:03 +08:00 committed by Greg Kroah-Hartman
parent d46d7516cb
commit d0cdcc3da9
1 changed files with 8 additions and 6 deletions
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12
net/mctp/route.c
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@ -147,6 +147,7 @@ static struct mctp_sk_key *mctp_key_alloc(struct mctp_sock *msk,
key->valid = true; key->valid = true;
spin_lock_init(&key->lock); spin_lock_init(&key->lock);
refcount_set(&key->refs, 1); refcount_set(&key->refs, 1);
sock_hold(key->sk);
return key; return key;
} }
@ -165,6 +166,7 @@ void mctp_key_unref(struct mctp_sk_key *key)
mctp_dev_release_key(key->dev, key); mctp_dev_release_key(key->dev, key);
spin_unlock_irqrestore(&key->lock, flags); spin_unlock_irqrestore(&key->lock, flags);
sock_put(key->sk);
kfree(key); kfree(key);
} }
@ -419,14 +421,14 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
* this function. * this function.
*/ */
rc = mctp_key_add(key, msk); rc = mctp_key_add(key, msk);
if (rc) { if (!rc)
kfree(key);
} else {
trace_mctp_key_acquire(key); trace_mctp_key_acquire(key);
/* we don't need to release key->lock on exit */ /* 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); mctp_key_unref(key);
}
key = NULL; key = NULL;
} else { } else {