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 E31CC448CED for ; Tue, 28 Jul 2026 14:27:47 +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=1785248869; cv=none; b=pwBil3QeCI512bOfqROWGEXb8whCytAdiEG6zGXfRFupm6moLN61Nv7BayCQvrn4IDLydQWh8W1MFSZgX8FokYPx3904XvuztJFfYZd+P5dbo4aHYjOn0QJDk72lkoTLJIZ1MHOta/u0NVnEBH9cg+AFXGXKqYnTmVKkvvXdaGw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785248869; c=relaxed/simple; bh=rKwSYjk1aa1lHnGWW/WvZEop4JlnNm0RfLvKXG998kk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fS/TyAHDcHmfTlS/+xIxUXmR1h8MO1nRSJLBLikAZmbZYm1/KnJbaeMsZM3d+XBF5l57t25acsrO/I92eH5tbUG/gAIMXOddO5MnBGu16Cq0OaAmS+NQNxgr+LHFptiGCDeoVtk9uBY4gkePLvhCiFAWUj3eMZxundFxKO2/apc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HHuTLnjy; 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="HHuTLnjy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9C591F000E9; Tue, 28 Jul 2026 14:27:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785248867; bh=YcL9OVbTyhL3FU0RnJODm8ggdAiNxqGq9/WhCqxfKl8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HHuTLnjyHEI6Lvr/6e2gSs6BdfGE/7ZLIwdmymTe7ij7QQ7JHaps8adGkQcDNM+cp 4m+Q8pWE5fyAuzhpmOj08IVG/um7hp7s45F/cICrqw49b5TkhrXjU8voAvzQp3s/Iw M8rYPW7mBsZRRmx6eRPJ6NnwxTNlhFaBkFF2PEjiGaG6EbrAXMySYElEhmki2AATp8 8J/Q7la6g85EMmyelqAGoNpDftBG676yLVtxVqTzns3SpqgaxU+ULcHJrC64PQhlFC Kl35Hlxa6Q7Y5F6X9L8qkmfWvISBtWtm5lT5qqk8iDH3j2HYP2Ge9e8hW37RGcrYxs fOaHLogTaIAwg== From: Sasha Levin To: stable@vger.kernel.org Cc: Maoyi Xie , Xiao Liang , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15.y] net: ip6_tunnel: require CAP_NET_ADMIN in the device netns for changelink Date: Tue, 28 Jul 2026 10:27:44 -0400 Message-ID: <20260728142744.4096199-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072024-poking-emit-1a0f@gregkh> References: <2026072024-poking-emit-1a0f@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 53930c28b69469..2a953c8922f150 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -2084,6 +2084,9 @@ 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