From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79AB53B19DE for ; Tue, 28 Jul 2026 15:43:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785253413; cv=none; b=lLko0S4U8gc8MR9UMasTwbsZRR3yxTZvwhb0XsnTskrwfX1tom6qq8cPAFhKDzAhWCT59kYGUlYkaGXm35TSFU2kEnIAuYFa4SBOzEigB431YJzKRbiZm1wqtVzdfKAozgM30bsQDRyohGU4Jwp2lOV1HAS2+zmhgS/O99IJxXM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785253413; c=relaxed/simple; bh=LylyFAlHSGBQn5uXkZ4ZbZWNSyG5Km3ZSDXpJQ/4I4o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sA8/LDlFaWjBkcBjHeUzuekDJ+LRg7CAW0ikIbFKEWn2pMPTfb++jAD1/Ep5mxhnBzxBCbrrW4X7rzm484B4yPN/sdS98+vKA7F3JWNAc4ArV0ZHaMNRx2ydMJ5wSSwslEYQLvBDmTcV41/419P/m0wt4jaLdkWLj7vb58sDHJk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A4QNfHaK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="A4QNfHaK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 587121F000E9; Tue, 28 Jul 2026 15:43:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785253412; bh=BNvAV33II6brkJ5jEhfuI7cLG6aVh6sx7ieUY8uTw60=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=A4QNfHaKLwx/GazwEhg/WRg1au1mEOvdOTkBhEY350kGsOPWWW0vfU7d/rIUkUXYo EtmrJoiY1XvrLXsQuUSXnl0EIYp9gbDpBTESh5YPmC98N/buPfYCF+iXUt+k0vCxPX fGqRI1CCD3ezq9YoavcCg9MWzEWwtXthgIltcbcKGR2YYgdBDn3SLoJoNhUFmcmxmq btQ7Eh8REKV1g3pTe21ojn6FYAoBlhN9wnRSahlhfjf/R48QFEjqrwUPp5f4LQnaU7 bYIqtqPrbdVBnsdbwnOyi/0yoCfVbbbWSt1UiVwd6CQJMkDUTrapfJtlko/NWSiInn /PxEpTWZPkXOg== From: Sasha Levin To: stable@vger.kernel.org Cc: Maoyi Xie , Xiao Liang , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10.y] net: ip6_tunnel: require CAP_NET_ADMIN in the device netns for changelink Date: Tue, 28 Jul 2026 11:43:29 -0400 Message-ID: <20260728154329.4192359-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072024-alkalize-reliably-1c7e@gregkh> References: <2026072024-alkalize-reliably-1c7e@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Maoyi Xie [ Upstream commit 2496fa0b7d180b3ad356b514e7ff93bb14e6140a ] ip6_tnl_changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->net. They differ once the device is created in or moved to a netns other than the one the request runs in. The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a caller privileged there but not in t->net can rewrite a tunnel that lives in t->net. Gate ip6_tnl_changelink() on rtnl_dev_link_net_capable() at its top, before any attribute is parsed. Reported-by: Xiao Liang Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/ Fixes: 0bd8762824e7 ("ip6tnl: add x-netns support") Cc: stable@vger.kernel.org Signed-off-by: Maoyi Xie Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260612085941.3158249-5-maoyixie.tju@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/ip6_tunnel.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index dda90c77f89840..f323bb514ba4fc 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -2113,6 +2113,9 @@ static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[], struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); struct ip_tunnel_encap ipencap; + if (!rtnl_dev_link_net_capable(dev, net)) + return -EPERM; + if (dev == ip6n->fb_tnl_dev) return -EINVAL; -- 2.53.0