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 D7E5122D7B9; Thu, 2 Jul 2026 16:54:17 +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=1783011259; cv=none; b=ZAtNGvECA1zZb54VYt0ubjqndoDzQcnKHx2psu6R99K07VcuecsndNypXjlflnPFkqAmgGw6lZLbe4nhOqZxVmtdfnBdJod+w6Bncc5R0ON5sSDRsiGcarWIZz8EtfgzJKCK/t6g9J/wEBhVToy4LyRsaDc8QsIsECu//sQXLX4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783011259; c=relaxed/simple; bh=idKv+JjEpQTnBockHZ5KDB6Mk/hyQsijDqYB1+35SRU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I29/dcKYzQc6dbzSwufcUGZ4cdGW2RlpMxtC4nGqyiev6aQCzhQOvZVNjv0dh0b2Lx3+GCz8NALBOf6ZSpXWUTdRftSvLr44IOcgrYVjP4fTllXmVM+mV8yDUgHVlvZupZpnF04OvXVRK47Cvu/39rrDM7cTpHPgjXXiuIZb8as= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YlyhmtYS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YlyhmtYS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2F2E1F00AC4; Thu, 2 Jul 2026 16:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783011257; bh=Ho9UVeP8z9wSKCGtebHbftHkBQxmvwmScGnNzHdDw/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YlyhmtYSC1bdsC872+oqjOxkSiOMIjQOMWwCIC2KWCtdOmFWB2ptW/E1wVkT64EjO GMa4rE5HltuN26OXSsCGsS+zhRNqjsRjFcNhi82h9GVebE7/OgAOi0PLkVIX8/fODE M0cfigtZ/70E7f8Vz/RAIHfZWIt0fpseq9yrsevA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiao Liang , Maoyi Xie , Kuniyuki Iwashima , Jakub Kicinski Subject: [PATCH 6.18 039/108] net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink Date: Thu, 2 Jul 2026 18:20:36 +0200 Message-ID: <20260702155112.919060696@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155112.110058792@linuxfoundation.org> References: <20260702155112.110058792@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maoyi Xie commit 8165f7ff57d9667d2bb477ef6af83ede7fed4ad7 upstream. A tunnel 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. Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is skipped when the link netns is dev_net(dev), where the rtnl path already checked it. The other patches in this series use the same helper. Gate ipgre_changelink() and erspan_changelink() with it, at the top of the op before any attribute is parsed, because the parsers update live tunnel fields first. ipgre_netlink_parms() sets t->collect_md before ip_tunnel_changelink() runs. Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().") added the same check on the ioctl path. This adds it on RTM_NEWLINK. Reported-by: Xiao Liang Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/ Fixes: b57708add314 ("gre: add x-netns support") Cc: stable@vger.kernel.org Signed-off-by: Maoyi Xie Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260612085941.3158249-2-maoyixie.tju@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- include/net/rtnetlink.h | 2 ++ net/core/rtnetlink.c | 8 ++++++++ net/ipv4/ip_gre.c | 6 ++++++ 3 files changed, 16 insertions(+) --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -256,6 +256,8 @@ int rtnl_configure_link(struct net_devic int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, struct netlink_ext_ack *exterr); struct net *rtnl_get_net_ns_capable(struct sock *sk, int netnsid); +bool rtnl_dev_link_net_capable(const struct net_device *dev, + const struct net *link_net); #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind) --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2414,6 +2414,14 @@ struct net *rtnl_get_net_ns_capable(stru } EXPORT_SYMBOL_GPL(rtnl_get_net_ns_capable); +bool rtnl_dev_link_net_capable(const struct net_device *dev, + const struct net *link_net) +{ + return net_eq(link_net, dev_net(dev)) || + ns_capable(link_net->user_ns, CAP_NET_ADMIN); +} +EXPORT_SYMBOL_GPL(rtnl_dev_link_net_capable); + static int rtnl_valid_dump_ifinfo_req(const struct nlmsghdr *nlh, bool strict_check, struct nlattr **tb, struct netlink_ext_ack *extack) --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1456,6 +1456,9 @@ static int ipgre_changelink(struct net_d __u32 fwmark = t->fwmark; int err; + if (!rtnl_dev_link_net_capable(dev, t->net)) + return -EPERM; + err = ipgre_newlink_encap_setup(dev, data); if (err) return err; @@ -1485,6 +1488,9 @@ static int erspan_changelink(struct net_ __u32 fwmark = t->fwmark; int err; + if (!rtnl_dev_link_net_capable(dev, t->net)) + return -EPERM; + err = ipgre_newlink_encap_setup(dev, data); if (err) return err;