[PATCH net 1/2] netdevsim: print IPsec salt/key in network byte order

[Andrei Gherzan <andrei.gherzan@canonical.com>]

nsim_sa.key[] and nsim_sa.salt hold raw key material in network byte
order, but are typed as plain u32 and printed with "%08x" in the
debugfs read handler. This prints host-endian, so output differs
between little- and big-endian hosts for the same key:

  little-endian: salt=0x61626364 key=0x34333231 38373635 32313039 36353433
  big-endian:    salt=0x64636261 key=0x31323334 35363738 39303132 33343536

This breaks selftests/net/rtnetlink.sh's ipsec_offload subtest on
big-endian (e.g. s390x), which hardcodes the little-endian output.

Retype key[]/salt to __be32, matching ipaddr[], and convert with
be32_to_cpu() before printing. Output is now network-order on every
host, independent of endianness.

A similar fix was proposed in 2022 but kept the u32 typing, so sparse
couldn't validate the added ntohl() calls and it stalled in review.
Retyping first avoids that problem. `make C=2` on netdevsim reports
the same zero warnings as before this change.

Selftest update follows in the next patch.

Fixes: 7699353da875 ("netdevsim: add ipsec offload testing")
Reported-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Link: https://lore.kernel.org/netdev/20220308135106.890270-1-kleber.souza@canonical.com/
Signed-off-by: Andrei Gherzan <andrei.gherzan@canonical.com>
---
 drivers/net/netdevsim/ipsec.c     | 10 +++++-----
 drivers/net/netdevsim/netdevsim.h |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/netdevsim/ipsec.c b/drivers/net/netdevsim/ipsec.c
index 36a1be4923d61..5722837bcda36 100644
--- a/drivers/net/netdevsim/ipsec.c
+++ b/drivers/net/netdevsim/ipsec.c
@@ -50,11 +50,11 @@ static ssize_t nsim_dbg_netdev_ops_read(struct file *filp,
 		p += scnprintf(p, bufsize - (p - buf),
 			       "sa[%i]    spi=0x%08x proto=0x%x salt=0x%08x crypt=%d\n",
 			       i, be32_to_cpu(sap->xs->id.spi),
-			       sap->xs->id.proto, sap->salt, sap->crypt);
+			       sap->xs->id.proto, be32_to_cpu(sap->salt), sap->crypt);
 		p += scnprintf(p, bufsize - (p - buf),
 			       "sa[%i]    key=0x%08x %08x %08x %08x\n",
-			       i, sap->key[0], sap->key[1],
-			       sap->key[2], sap->key[3]);
+			       i, be32_to_cpu(sap->key[0]), be32_to_cpu(sap->key[1]),
+			       be32_to_cpu(sap->key[2]), be32_to_cpu(sap->key[3]));
 	}
 
 	len = simple_read_from_buffer(buffer, count, ppos, buf, p - buf);
@@ -87,7 +87,7 @@ static int nsim_ipsec_find_empty_idx(struct nsim_ipsec *ipsec)
 
 static int nsim_ipsec_parse_proto_keys(struct net_device *dev,
 				       struct xfrm_state *xs,
-				       u32 *mykey, u32 *mysalt)
+				       __be32 *mykey, __be32 *mysalt)
 {
 	const char aes_gcm_name[] = "rfc4106(gcm(aes))";
 	unsigned char *key_data;
@@ -117,7 +117,7 @@ static int nsim_ipsec_parse_proto_keys(struct net_device *dev,
 
 	/* 160 accounts for 16 byte key and 4 byte salt */
 	if (key_len > NSIM_IPSEC_AUTH_BITS) {
-		*mysalt = ((u32 *)key_data)[4];
+		*mysalt = ((__be32 *)key_data)[4];
 	} else if (key_len == NSIM_IPSEC_AUTH_BITS) {
 		*mysalt = 0;
 	} else {
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 55aec41237b9b..a82a685384e6d 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -42,8 +42,8 @@
 struct nsim_sa {
 	struct xfrm_state *xs;
 	__be32 ipaddr[4];
-	u32 key[4];
-	u32 salt;
+	__be32 key[4];
+	__be32 salt;
 	bool used;
 	bool crypt;
 	bool rx;
-- 
2.43.0