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 4553943E9CB for ; Tue, 28 Jul 2026 13:30:36 +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=1785245441; cv=none; b=ClRc4m1bE5er5YgI4HHSV+E9GgQeDSWoHG3OTYbH3UujHGHPWLaBetctUvgekiAptRxAzMkrSvrNcFrylwhAvWo1vX9OTOFoOiOqll/Vpueqw/N125w1RRHPzDSikQ/TD13dPzj12FN3Wy37zSDVEZlMiRr0atcvYBBpjsbhvzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785245441; c=relaxed/simple; bh=JYif+IVnSPZkheG2x8dSrO5ARN3Z/tsJlNbhOMSsroI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c7RYgOmndKT14WZTDFoCYpcjA8rnF28iMYgjpRTaSjlg3nTGoXUDiwCVW8aDj5XvSXylkxux7vYZZ/NijeGmlxN5Phw1QfcF7ibqW0kKNCc5raGtDezQ36Z+I92thh3lRJ/+jqQmlgzlGFRpotUgmkYMF0pQF5nFjshDAB49c5c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m1mXfO1u; 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="m1mXfO1u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AEDD1F000E9; Tue, 28 Jul 2026 13:30:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785245436; bh=Vey5SccemvtbQ6uXlCU9hOBFrSqDra/PKWnJA7I9Mnc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=m1mXfO1u0TahkBfyFPL6DyR0T/AQmYoZBPWEIlim9FLA51h1Xdii4bmp855AqeZPP DDZjcRCvkalhCvfJYDyQA8/r4YgaKRKgC2VmxNx0iUo4eMrq2lrjydtzTtEqW9f1eC p5d2GOnO+Uq5QrYvPZ/nAoaLflWJtRfFIabkr/I+Q+724sOyyFsYz8dmklTm5E8qF/ Ki3MIV/bk3U9E6saBLa9UeUqd7VOH/fYsvPWxnSDZLEOQWYnCIA53+S3gAVm9A2su8 9qH9rOOUNvOcUROMBazOp5lWhqW++u1xOsA3GUw220VPWTwF4mRoIsMSq6bi20M4lS 3sid1ag8+lMKg== From: Sasha Levin To: stable@vger.kernel.org Cc: Maoyi Xie , Xiao Liang , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y] net: ip6_tunnel: require CAP_NET_ADMIN in the device netns for changelink Date: Tue, 28 Jul 2026 09:30:33 -0400 Message-ID: <20260728133033.3965038-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072023-majesty-rubbing-2664@gregkh> References: <2026072023-majesty-rubbing-2664@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 5a2583a82f974f..825d40b505cde7 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -2055,6 +2055,9 @@ 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