From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 6e54ea37e344f145665c2dc3cc534b92529e8de5 ]
Currently, we have a race where we look up a sock through a "general" (ie, not directly associated with the (src,dest,tag) tuple) key, then drop the key reference while still holding the key's sock.
This change expands the key reference until we've finished using the sock, and hence the sock reference too.
Commit message changes from Jeremy Kerr jk@codeconstruct.com.au.
Reported-by: Noam Rathaus noamr@ssd-disclosure.com Fixes: 73c618456dc5 ("mctp: locking, lifetime and validity changes for sk_keys") Signed-off-by: Paolo Abeni pabeni@redhat.com 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 --- net/mctp/route.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/net/mctp/route.c b/net/mctp/route.c index ce10ba7ae839..06c0de21984d 100644 --- a/net/mctp/route.c +++ b/net/mctp/route.c @@ -317,8 +317,8 @@ static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb)
static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) { + struct mctp_sk_key *key, *any_key = NULL; struct net *net = dev_net(skb->dev); - struct mctp_sk_key *key; struct mctp_sock *msk; struct mctp_hdr *mh; unsigned long f; @@ -363,13 +363,11 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) * key for reassembly - we'll create a more specific * one for future packets if required (ie, !EOM). */ - key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f); - if (key) { - msk = container_of(key->sk, + any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f); + if (any_key) { + msk = container_of(any_key->sk, struct mctp_sock, sk); - spin_unlock_irqrestore(&key->lock, f); - mctp_key_unref(key); - key = NULL; + spin_unlock_irqrestore(&any_key->lock, f); } }
@@ -475,6 +473,8 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) spin_unlock_irqrestore(&key->lock, f); mctp_key_unref(key); } + if (any_key) + mctp_key_unref(any_key); out: if (rc) kfree_skb(skb);