net: mctp: take ownership of skb in mctp_local_output

[ Upstream commit 3773d65ae5 ]

Currently, mctp_local_output only takes ownership of skb on success, and
we may leak an skb if mctp_local_output fails in specific states; the
skb ownership isn't transferred until the actual output routing occurs.

Instead, make mctp_local_output free the skb on all error paths up to
the route action, so it always consumes the passed skb.

Fixes: 833ef3b91d ("mctp: Populate socket implementation")
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240220081053.1439104-1-jk@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jeremy Kerr 2024-02-20 16:10:53 +08:00 committed by Greg Kroah-Hartman
parent ab63de24eb
commit a3c8fa54e9
2 changed files with 9 additions and 2 deletions

View file

@ -249,6 +249,7 @@ struct mctp_route {
struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
mctp_eid_t daddr);
/* always takes ownership of skb */
int mctp_local_output(struct sock *sk, struct mctp_route *rt,
struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);

View file

@ -888,7 +888,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex);
if (!dev) {
rcu_read_unlock();
return rc;
goto out_free;
}
rt->dev = __mctp_dev_get(dev);
rcu_read_unlock();
@ -903,7 +903,8 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
rt->mtu = 0;
} else {
return -EINVAL;
rc = -EINVAL;
goto out_free;
}
spin_lock_irqsave(&rt->dev->addrs_lock, flags);
@ -966,12 +967,17 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
rc = mctp_do_fragment_route(rt, skb, mtu, tag);
}
/* route output functions consume the skb, even on error */
skb = NULL;
out_release:
if (!ext_rt)
mctp_route_release(rt);
mctp_dev_put(tmp_rt.dev);
out_free:
kfree_skb(skb);
return rc;
}