FAILED: patch "[PATCH] net: ipip: require CAP_NET_ADMIN in the device netns for" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] net: ipip: require CAP_NET_ADMIN in the device netns for" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 8211a26324667980a463c069469a818e71207e02
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072005-sabotage-stylized-6dae@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8211a26324667980a463c069469a818e71207e02 Mon Sep 17 00:00:00 2001
From: Maoyi Xie <maoyixie.tju@gmail.com>
Date: Fri, 12 Jun 2026 16:59:36 +0800
Subject: [PATCH] net: ipip: require CAP_NET_ADMIN in the device netns for
 changelink

ipip_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 ipip_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.

Reported-by: Xiao Liang <shaw.leon@gmail.com>
Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/
Fixes: 6c742e714d8c ("ipip: add x-netns support")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260612085941.3158249-3-maoyixie.tju@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 4f89a03e0b49..b643194f57d2 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -494,6 +494,9 @@ static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
 	bool collect_md;
 	__u32 fwmark = t->fwmark;
 
+	if (!rtnl_dev_link_net_capable(dev, t->net))
+		return -EPERM;
+
 	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		int err = ip_tunnel_encap_setup(t, &ipencap);
 

[PATCH 5.15.y 1/2] net: Add helper function to parse netlink msg of ip_tunnel_encap

[Sasha Levin]

From: Liu Jian <liujian56@huawei.com>

[ Upstream commit 537dd2d9fb9f4aa7939fb4fcf552ebe4f497bd7e ]

Add ip_tunnel_netlink_encap_parms to parse netlink msg of ip_tunnel_encap.
Reduces duplicate code, no actual functional changes.

Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 8211a2632466 ("net: ipip: require CAP_NET_ADMIN in the device netns for changelink")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/ip_tunnels.h  |  3 +++
 net/ipv4/ip_tunnel_core.c | 35 +++++++++++++++++++++++++++++++++++
 net/ipv4/ipip.c           | 38 ++------------------------------------
 net/ipv6/ip6_tunnel.c     | 37 ++-----------------------------------
 net/ipv6/sit.c            | 38 ++------------------------------------
 5 files changed, 44 insertions(+), 107 deletions(-)

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 7ca06cf6e0f798..0d71e7c4c69163 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -296,6 +296,9 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
 		      struct ip_tunnel_parm *p, __u32 fwmark);
 void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
 
+bool ip_tunnel_netlink_encap_parms(struct nlattr *data[],
+				   struct ip_tunnel_encap *encap);
+
 extern const struct header_ops ip_tunnel_header_ops;
 __be16 ip_tunnel_parse_protocol(const struct sk_buff *skb);
 
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index f535b875a02b88..3b91b943e9a9a4 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -1091,3 +1091,38 @@ EXPORT_SYMBOL(ip_tunnel_parse_protocol);
 
 const struct header_ops ip_tunnel_header_ops = { .parse_protocol = ip_tunnel_parse_protocol };
 EXPORT_SYMBOL(ip_tunnel_header_ops);
+
+/* This function returns true when ENCAP attributes are present in the nl msg */
+bool ip_tunnel_netlink_encap_parms(struct nlattr *data[],
+				   struct ip_tunnel_encap *encap)
+{
+	bool ret = false;
+
+	memset(encap, 0, sizeof(*encap));
+
+	if (!data)
+		return ret;
+
+	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
+		ret = true;
+		encap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
+	}
+
+	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
+		ret = true;
+		encap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
+	}
+
+	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
+		ret = true;
+		encap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
+	}
+
+	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
+		ret = true;
+		encap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_netlink_encap_parms);
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 3aa78ccbec3ed8..ae4bd3a3ef8156 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -448,40 +448,6 @@ static void ipip_netlink_parms(struct nlattr *data[],
 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
 }
 
-/* This function returns true when ENCAP attributes are present in the nl msg */
-static bool ipip_netlink_encap_parms(struct nlattr *data[],
-				     struct ip_tunnel_encap *ipencap)
-{
-	bool ret = false;
-
-	memset(ipencap, 0, sizeof(*ipencap));
-
-	if (!data)
-		return ret;
-
-	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
-		ret = true;
-		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
-		ret = true;
-		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
-		ret = true;
-		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
-		ret = true;
-		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
-	}
-
-	return ret;
-}
-
 static int ipip_newlink(struct net *src_net, struct net_device *dev,
 			struct nlattr *tb[], struct nlattr *data[],
 			struct netlink_ext_ack *extack)
@@ -491,7 +457,7 @@ static int ipip_newlink(struct net *src_net, struct net_device *dev,
 	struct ip_tunnel_encap ipencap;
 	__u32 fwmark = 0;
 
-	if (ipip_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		int err = ip_tunnel_encap_setup(t, &ipencap);
 
 		if (err < 0)
@@ -512,7 +478,7 @@ static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
 	bool collect_md;
 	__u32 fwmark = t->fwmark;
 
-	if (ipip_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		int err = ip_tunnel_encap_setup(t, &ipencap);
 
 		if (err < 0)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 53930c28b69469..8c7d5f391bb305 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -2005,39 +2005,6 @@ static void ip6_tnl_netlink_parms(struct nlattr *data[],
 		parms->fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
 }
 
-static bool ip6_tnl_netlink_encap_parms(struct nlattr *data[],
-					struct ip_tunnel_encap *ipencap)
-{
-	bool ret = false;
-
-	memset(ipencap, 0, sizeof(*ipencap));
-
-	if (!data)
-		return ret;
-
-	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
-		ret = true;
-		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
-		ret = true;
-		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
-		ret = true;
-		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
-		ret = true;
-		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
-	}
-
-	return ret;
-}
-
 static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
 			   struct nlattr *tb[], struct nlattr *data[],
 			   struct netlink_ext_ack *extack)
@@ -2050,7 +2017,7 @@ static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
 
 	nt = netdev_priv(dev);
 
-	if (ip6_tnl_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		err = ip6_tnl_encap_setup(nt, &ipencap);
 		if (err < 0)
 			return err;
@@ -2087,7 +2054,7 @@ static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (dev == ip6n->fb_tnl_dev)
 		return -EINVAL;
 
-	if (ip6_tnl_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		int err = ip6_tnl_encap_setup(t, &ipencap);
 
 		if (err < 0)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 733362dcc653a4..4b16ddc3d6c7f3 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1545,40 +1545,6 @@ static void ipip6_netlink_parms(struct nlattr *data[],
 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
 }
 
-/* This function returns true when ENCAP attributes are present in the nl msg */
-static bool ipip6_netlink_encap_parms(struct nlattr *data[],
-				      struct ip_tunnel_encap *ipencap)
-{
-	bool ret = false;
-
-	memset(ipencap, 0, sizeof(*ipencap));
-
-	if (!data)
-		return ret;
-
-	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
-		ret = true;
-		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
-		ret = true;
-		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
-		ret = true;
-		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
-	}
-
-	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
-		ret = true;
-		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
-	}
-
-	return ret;
-}
-
 #ifdef CONFIG_IPV6_SIT_6RD
 /* This function returns true when 6RD attributes are present in the nl msg */
 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
@@ -1630,7 +1596,7 @@ static int ipip6_newlink(struct net *src_net, struct net_device *dev,
 
 	nt = netdev_priv(dev);
 
-	if (ipip6_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		err = ip_tunnel_encap_setup(nt, &ipencap);
 		if (err < 0)
 			return err;
@@ -1685,7 +1651,7 @@ static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (dev == sitn->fb_tunnel_dev)
 		return -EINVAL;
 
-	if (ipip6_netlink_encap_parms(data, &ipencap)) {
+	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		err = ip_tunnel_encap_setup(t, &ipencap);
 		if (err < 0)
 			return err;
-- 
2.53.0

[PATCH 5.15.y 2/2] net: ipip: require CAP_NET_ADMIN in the device netns for changelink

[Sasha Levin]

From: Maoyi Xie <maoyixie.tju@gmail.com>

[ Upstream commit 8211a26324667980a463c069469a818e71207e02 ]

ipip_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 ipip_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.

Reported-by: Xiao Liang <shaw.leon@gmail.com>
Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/
Fixes: 6c742e714d8c ("ipip: add x-netns support")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260612085941.3158249-3-maoyixie.tju@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/ipip.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index ae4bd3a3ef8156..d22d8e5f4abc1b 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -478,6 +478,9 @@ static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
 	bool collect_md;
 	__u32 fwmark = t->fwmark;
 
+	if (!rtnl_dev_link_net_capable(dev, t->net))
+		return -EPERM;
+
 	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		int err = ip_tunnel_encap_setup(t, &ipencap);
 
-- 
2.53.0