FAILED: patch "[PATCH] netfilter: nf_conntrack_netlink: fix inverted IPv6 tuple filter" failed to apply to 6.18-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x cd37ab22a74e05aae5c16c67295cbf5188b16268
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107051236-failed-6.18-cd37ab22a74e@kernel.org' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From cd37ab22a74e05aae5c16c67295cbf5188b16268 Mon Sep 17 00:00:00 2001
From: Liu Chao <liuc63@xiaopeng.com>
Date: Mon, 19 Oct 2026 15:56:26 +0800
Subject: [PATCH] netfilter: nf_conntrack_netlink: fix inverted IPv6 tuple
 filter

ctnetlink_filter_match_tuple() returns 0 (no match) when the IPv6
source or destination address differs from the filter, because the
!ipv6_addr_cmp() test is inverted.  ipv6_addr_cmp() returns 0 when
the addresses are equal, so the negation makes the branch trigger on
a match instead of a mismatch, which is the opposite of the IPv4
path above.

Drop the '!' so the IPv6 branch returns 0 only when the addresses
differ, matching the IPv4 semantics and the caller's expectation.

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Cc: stable@vger.kernel.org
Signed-off-by: Liu Chao <liuc63@xiaopeng.com>
Reviewed-by: Weibin Liu <liuwb@xiaopeng.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_netlink.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 4e5d7c7014368..cc8695d5356d2 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1098,13 +1098,13 @@ static int ctnetlink_filter_match_tuple(struct nf_conntrack_tuple *filter_tuple,
 		break;
 	case NFPROTO_IPV6:
 		if ((flags & CTA_FILTER_FLAG(CTA_IP_SRC)) &&
-		    !ipv6_addr_cmp(&filter_tuple->src.u3.in6,
-				   &ct_tuple->src.u3.in6))
+		    ipv6_addr_cmp(&filter_tuple->src.u3.in6,
+				  &ct_tuple->src.u3.in6))
 			return 0;
 
 		if ((flags & CTA_FILTER_FLAG(CTA_IP_DST)) &&
-		    !ipv6_addr_cmp(&filter_tuple->dst.u3.in6,
-				   &ct_tuple->dst.u3.in6))
+		    ipv6_addr_cmp(&filter_tuple->dst.u3.in6,
+				  &ct_tuple->dst.u3.in6))
 			return 0;
 		break;
 	}
-- 
2.53.0