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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tom Rix <trix@redhat.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.16 1021/1039] net: mscc: ocelot: fix using match before it is set
Date:   Mon, 24 Jan 2022 19:46:50 +0100
Message-Id: <20220124184159.618850150@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
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From: Tom Rix <trix@redhat.com>

commit baa59504c1cd0cca7d41954a45ee0b3dc78e41a0 upstream.

Clang static analysis reports this issue
ocelot_flower.c:563:8: warning: 1st function call argument
  is an uninitialized value
    !is_zero_ether_addr(match.mask->dst)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The variable match is used before it is set.  So move the
block.

Fixes: 75944fda1dfe ("net: mscc: ocelot: offload ingress skbedit and vlan actions to VCAP IS1")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mscc/ocelot_flower.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mscc/ocelot_flower.c
+++ b/drivers/net/ethernet/mscc/ocelot_flower.c
@@ -521,13 +521,6 @@ ocelot_flower_parse_key(struct ocelot *o
 			return -EOPNOTSUPP;
 		}
 
-		if (filter->block_id == VCAP_IS1 &&
-		    !is_zero_ether_addr(match.mask->dst)) {
-			NL_SET_ERR_MSG_MOD(extack,
-					   "Key type S1_NORMAL cannot match on destination MAC");
-			return -EOPNOTSUPP;
-		}
-
 		/* The hw support mac matches only for MAC_ETYPE key,
 		 * therefore if other matches(port, tcp flags, etc) are added
 		 * then just bail out
@@ -542,6 +535,14 @@ ocelot_flower_parse_key(struct ocelot *o
 			return -EOPNOTSUPP;
 
 		flow_rule_match_eth_addrs(rule, &match);
+
+		if (filter->block_id == VCAP_IS1 &&
+		    !is_zero_ether_addr(match.mask->dst)) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Key type S1_NORMAL cannot match on destination MAC");
+			return -EOPNOTSUPP;
+		}
+
 		filter->key_type = OCELOT_VCAP_KEY_ETYPE;
 		ether_addr_copy(filter->key.etype.dmac.value,
 				match.key->dst);