[PATCH 6.6.y 1/4] net: mctp: avoid confusion over local/peer dest/source addresses

[Sasha Levin <sashal@kernel.org>]

From: Jeremy Kerr <jk@codeconstruct.com.au>

[ Upstream commit ee076b73e576b0a052d5686d873346b285ae50ea ]

We have a double-swap of local and peer addresses in
mctp_alloc_local_tag; the arguments in both call sites are swapped, but
there is also a swap in the implementation of alloc_local_tag. This is
opaque because we're using source/dest address references, which don't
match the local/peer semantics.

Avoid this confusion by naming the arguments as 'local' and 'peer', and
remove the double swap. The calling order now matches mctp_key_alloc.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Stable-dep-of: 26cc0e69cce0 ("mctp: route: iterate socket tag list in mctp_lookup_prealloc_tag()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/mctp.h |  4 ++--
 net/mctp/af_mctp.c |  2 +-
 net/mctp/route.c   | 16 ++++++++--------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/net/mctp.h b/include/net/mctp.h
index 6dbed4ca22205..d7e331ce099ad 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -90,7 +90,7 @@ struct mctp_sock {
 };
 
 /* Key for matching incoming packets to sockets or reassembly contexts.
- * Packets are matched on (src,dest,tag).
+ * Packets are matched on (peer EID, local EID, tag).
  *
  * Lifetime / locking requirements:
  *
@@ -258,7 +258,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
 
 void mctp_key_unref(struct mctp_sk_key *key);
 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
-					 mctp_eid_t daddr, mctp_eid_t saddr,
+					 mctp_eid_t local, mctp_eid_t peer,
 					 bool manual, u8 *tagp);
 
 /* routing <--> device interface */
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index 805f7376cebe3..d6e0350b1c949 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -366,7 +366,7 @@ static int mctp_ioctl_alloctag(struct mctp_sock *msk, unsigned long arg)
 	if (ctl.flags)
 		return -EINVAL;
 
-	key = mctp_alloc_local_tag(msk, ctl.peer_addr, MCTP_ADDR_ANY,
+	key = mctp_alloc_local_tag(msk, MCTP_ADDR_ANY, ctl.peer_addr,
 				   true, &tag);
 	if (IS_ERR(key))
 		return PTR_ERR(key);
diff --git a/net/mctp/route.c b/net/mctp/route.c
index 6d6e19c049396..3e21bc0a88688 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -619,11 +619,11 @@ static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
 	refcount_inc(&key->refs);
 }
 
-/* Allocate a locally-owned tag value for (saddr, daddr), and reserve
+/* Allocate a locally-owned tag value for (local, peer), and reserve
  * it for the socket msk
  */
 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
-					 mctp_eid_t daddr, mctp_eid_t saddr,
+					 mctp_eid_t local, mctp_eid_t peer,
 					 bool manual, u8 *tagp)
 {
 	struct net *net = sock_net(&msk->sk);
@@ -633,11 +633,11 @@ struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
 	u8 tagbits;
 
 	/* for NULL destination EIDs, we may get a response from any peer */
-	if (daddr == MCTP_ADDR_NULL)
-		daddr = MCTP_ADDR_ANY;
+	if (peer == MCTP_ADDR_NULL)
+		peer = MCTP_ADDR_ANY;
 
 	/* be optimistic, alloc now */
-	key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
+	key = mctp_key_alloc(msk, local, peer, 0, GFP_KERNEL);
 	if (!key)
 		return ERR_PTR(-ENOMEM);
 
@@ -658,8 +658,8 @@ struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
 		if (tmp->tag & MCTP_HDR_FLAG_TO)
 			continue;
 
-		if (!(mctp_address_matches(tmp->peer_addr, daddr) &&
-		      mctp_address_matches(tmp->local_addr, saddr)))
+		if (!(mctp_address_matches(tmp->peer_addr, peer) &&
+		      mctp_address_matches(tmp->local_addr, local)))
 			continue;
 
 		spin_lock(&tmp->lock);
@@ -951,7 +951,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
 			key = mctp_lookup_prealloc_tag(msk, daddr,
 						       req_tag, &tag);
 		else
-			key = mctp_alloc_local_tag(msk, daddr, saddr,
+			key = mctp_alloc_local_tag(msk, saddr, daddr,
 						   false, &tag);
 
 		if (IS_ERR(key)) {
-- 
2.53.0