6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jeremy Kerr jk@codeconstruct.com.au
[ Upstream commit 3773d65ae5154ed7df404b050fd7387a36ab5ef3 ]
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: 833ef3b91de6 ("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 --- include/net/mctp.h | 1 + net/mctp/route.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/net/mctp.h b/include/net/mctp.h index 82800d521c3de..7ed84054f4623 100644 --- a/include/net/mctp.h +++ b/include/net/mctp.h @@ -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);
diff --git a/net/mctp/route.c b/net/mctp/route.c index 256bf0b89e6ca..0144d8ebdaefb 100644 --- a/net/mctp/route.c +++ b/net/mctp/route.c @@ -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; }