net: mctp: put sock on tag allocation failure

[ Upstream commit 9990889be14288d4f1743e4768222d5032a79c27 ]

We may hold an extra reference on a socket if a tag allocation fails: we
optimistically allocate the sk_key, and take a ref there, but do not
drop if we end up not using the allocated key.

Ensure we're dropping the sock on this failure by doing a proper unref
rather than directly kfree()ing.

Fixes: de8a6b15d965 ("net: mctp: add an explicit reference from a mctp_sk_key to sock")
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/ce9b61e44d1cdae7797be0c5e3141baf582d23a0.1707983487.git.jk@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mctp/route.c b/net/mctp/route.c
index 68be8f2b622dd144b2ecb3a11ff59a1f018b0c86..256bf0b89e6ca378ea9dee6118034f55e33a38d2 100644 (file)
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -663,7 +663,7 @@ struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
        spin_unlock_irqrestore(&mns->keys_lock, flags);
 
        if (!tagbits) {
-               kfree(key);
+               mctp_key_unref(key);
                return ERR_PTR(-EBUSY);
        }