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 0F1D61ACEDE for ; Tue, 28 Jul 2026 13:19:55 +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=1785244797; cv=none; b=MfTfNj1LobTZL5YbTDQrTBGP85ggvUzv4VIfT2QfljHeTdGIlJ9ypEBwXAZPmXk/9Q9sZlh8qtdD+kffcfYMGlFbE7GlbIeqFYXeppud6f8uBX5aMHxkVk37IIJlZIv5uixXAd7T7w5/0uwIfO/rMohlEWmOn2DgQgvBUWC24Yg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785244797; c=relaxed/simple; bh=cGLR5hsIR5GAzbJypL/PMOCdv0lFGx6kPlIHZxF3Vk8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ujemKFNaKx5Akv0UFZ35Yds3KNNPIaNydijgoEAUu3By5NkaMpCK8V5NbOoQ+Qd/lEdx1oJ23rG0F4Cc1wEYzNHWHS4gFpEqvEQzSxRAHlntzJ66thVOh9R3fw4hdvNIBSins1uTQ9e3zcEag7SSclx5Up2FQ6HqSHN0Mnd+ahk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K2ssooxl; 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="K2ssooxl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEDDE1F000E9; Tue, 28 Jul 2026 13:19:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785244795; bh=yJTNF07kupbbvpYvgV2XDWABF0/2zG3wX3UouCO9O3Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K2ssooxlOQNxA5iWueAOjpJUllXuy9/J5mKjEM+v1WJFOjVDdRPdF7Ee0hs5GKITN fbisfcZl63lT6NTeGJHTmEdOdTT5yGJD8tm03hS8QfLFE2WkA8DUtL1ipLXku5tuQA or1ME9QRG23pEbSpd9LBq0cM07Facass1wzl5Kz3iKiUjpph53XLa0QZAcrsgVMI/v JcKvzhqTVRVGUWCr4ErytOGU+7nPSlGOGAkzBcCshOalsznrpQfwSXXkCfwhdhHFrY 18BWSzjflZajZIn5Ix6Lqtz5mXQnwjJ+MFTwelzTupPy1AiPvm9/HLA9Fhl84SeSJJ Shj2Q+BqfGyqg== From: Sasha Levin To: stable@vger.kernel.org Cc: Maoyi Xie , Xiao Liang , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y] net: ip6_tunnel: require CAP_NET_ADMIN in the device netns for changelink Date: Tue, 28 Jul 2026 09:19:53 -0400 Message-ID: <20260728131953.3953668-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072023-unwashed-factoid-cc13@gregkh> References: <2026072023-unwashed-factoid-cc13@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 f0a8350eb52eb0..b788a06bd3a543 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -2053,6 +2053,9 @@ 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