From e16b859872b87650bb55b12cca5a5fcdc49c1442 Mon Sep 17 00:00:00 2001
From: Martin Willi <martin@strongswan.org>
Date: Tue, 12 Apr 2022 11:34:57 +0200
Subject: [PATCH] macvlan: Fix leaking skb in source mode with nodst option
Git-commit: e16b859872b87650bb55b12cca5a5fcdc49c1442
Patch-mainline: v5.18-rc3
References: CVE-2022-3526 bsc#1204353 git-fixes

The MACVLAN receive handler clones skbs to all matching source MACVLAN
interfaces, before it passes the packet along to match on destination
based MACVLANs.

When using the MACVLAN nodst mode, passing the packet to destination based
MACVLANs is omitted and the handler returns with RX_HANDLER_CONSUMED.
However, the passed skb is not freed, leaking for any packet processed
with the nodst option.

Properly free the skb when consuming packets to fix that leak.

Fixes: 427f0c8c194b ("macvlan: Add nodst option to macvlan type source")
Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/macvlan.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 069e8824c264..b00bc8173abe 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -460,8 +460,10 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 			return RX_HANDLER_CONSUMED;
 		*pskb = skb;
 		eth = eth_hdr(skb);
-		if (macvlan_forward_source(skb, port, eth->h_source))
+		if (macvlan_forward_source(skb, port, eth->h_source)) {
+			kfree_skb(skb);
 			return RX_HANDLER_CONSUMED;
+		}
 		src = macvlan_hash_lookup(port, eth->h_source);
 		if (src && src->mode != MACVLAN_MODE_VEPA &&
 		    src->mode != MACVLAN_MODE_BRIDGE) {
@@ -480,8 +482,10 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 		return RX_HANDLER_PASS;
 	}
 
-	if (macvlan_forward_source(skb, port, eth->h_source))
+	if (macvlan_forward_source(skb, port, eth->h_source)) {
+		kfree_skb(skb);
 		return RX_HANDLER_CONSUMED;
+	}
 	if (macvlan_passthru(port))
 		vlan = list_first_or_null_rcu(&port->vlans,
 					      struct macvlan_dev, list);
-- 
2.31.1