In a 802.1X scenario, clients connected to a bridge port shall not
be allowed to have traffic forwarded until fully authenticated.
A static fdb entry of the clients MAC address for the bridge port
unlocks the client and allows bidirectional communication.
This scenario is facilitated with setting the bridge port in locked
mode, which is also supported by various switchcore chipsets.
Signed-off-by: Hans Schultz <[email protected]>
---
include/linux/if_bridge.h | 1 +
include/uapi/linux/if_link.h | 1 +
net/bridge/br_input.c | 10 +++++++++-
net/bridge/br_netlink.c | 6 +++++-
4 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 509e18c7e740..3aae023a9353 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -58,6 +58,7 @@ struct br_ip_list {
#define BR_MRP_LOST_CONT BIT(18)
#define BR_MRP_LOST_IN_CONT BIT(19)
#define BR_TX_FWD_OFFLOAD BIT(20)
+#define BR_PORT_LOCKED BIT(21)
#define BR_DEFAULT_AGEING_TIME (300 * HZ)
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 6218f93f5c1a..a45cc0a1f415 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -537,6 +537,7 @@ enum {
IFLA_BRPORT_MRP_IN_OPEN,
IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT,
IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
+ IFLA_BRPORT_LOCKED,
__IFLA_BRPORT_MAX
};
#define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index b50382f957c1..469e3adbce07 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -69,6 +69,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
struct net_bridge_port *p = br_port_get_rcu(skb->dev);
enum br_pkt_type pkt_type = BR_PKT_UNICAST;
struct net_bridge_fdb_entry *dst = NULL;
+ struct net_bridge_fdb_entry *fdb_entry;
struct net_bridge_mcast_port *pmctx;
struct net_bridge_mdb_entry *mdst;
bool local_rcv, mcast_hit = false;
@@ -81,6 +82,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
if (!p || p->state == BR_STATE_DISABLED)
goto drop;
+ br = p->br;
+
brmctx = &p->br->multicast_ctx;
pmctx = &p->multicast_ctx;
state = p->state;
@@ -88,10 +91,15 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
&state, &vlan))
goto out;
+ if (p->flags & BR_PORT_LOCKED) {
+ fdb_entry = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
+ if (!(fdb_entry && fdb_entry->dst == p))
+ goto drop;
+ }
+
nbp_switchdev_frame_mark(p, skb);
/* insert into forwarding database after filtering to avoid spoofing */
- br = p->br;
if (p->flags & BR_LEARNING)
br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 2ff83d84230d..7d4432ca9a20 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -184,6 +184,7 @@ static inline size_t br_port_info_size(void)
+ nla_total_size(1) /* IFLA_BRPORT_VLAN_TUNNEL */
+ nla_total_size(1) /* IFLA_BRPORT_NEIGH_SUPPRESS */
+ nla_total_size(1) /* IFLA_BRPORT_ISOLATED */
+ + nla_total_size(1) /* IFLA_BRPORT_LOCKED */
+ nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_ROOT_ID */
+ nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_BRIDGE_ID */
+ nla_total_size(sizeof(u16)) /* IFLA_BRPORT_DESIGNATED_PORT */
@@ -269,7 +270,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
BR_MRP_LOST_CONT)) ||
nla_put_u8(skb, IFLA_BRPORT_MRP_IN_OPEN,
!!(p->flags & BR_MRP_LOST_IN_CONT)) ||
- nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)))
+ nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)) ||
+ nla_put_u8(skb, IFLA_BRPORT_LOCKED, !!(p->flags & BR_PORT_LOCKED)))
return -EMSGSIZE;
timerval = br_timer_value(&p->message_age_timer);
@@ -827,6 +829,7 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
[IFLA_BRPORT_GROUP_FWD_MASK] = { .type = NLA_U16 },
[IFLA_BRPORT_NEIGH_SUPPRESS] = { .type = NLA_U8 },
[IFLA_BRPORT_ISOLATED] = { .type = NLA_U8 },
+ [IFLA_BRPORT_LOCKED] = { .type = NLA_U8 },
[IFLA_BRPORT_BACKUP_PORT] = { .type = NLA_U32 },
[IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT] = { .type = NLA_U32 },
};
@@ -893,6 +896,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
br_set_port_flag(p, tb, IFLA_BRPORT_VLAN_TUNNEL, BR_VLAN_TUNNEL);
br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_SUPPRESS, BR_NEIGH_SUPPRESS);
br_set_port_flag(p, tb, IFLA_BRPORT_ISOLATED, BR_ISOLATED);
+ br_set_port_flag(p, tb, IFLA_BRPORT_LOCKED, BR_PORT_LOCKED);
changed_mask = old_flags ^ p->flags;
--
2.30.2
On Thu, Feb 10, 2022 at 10:30:01AM +0200, Nikolay Aleksandrov wrote:
> On 09/02/2022 15:05, Hans Schultz wrote:
> > In a 802.1X scenario, clients connected to a bridge port shall not
> > be allowed to have traffic forwarded until fully authenticated.
> > A static fdb entry of the clients MAC address for the bridge port
> > unlocks the client and allows bidirectional communication.
> >
> > This scenario is facilitated with setting the bridge port in locked
> > mode, which is also supported by various switchcore chipsets.
> >
> > Signed-off-by: Hans Schultz <[email protected]>
> > ---
>
> Hi,
> I'm writing from my private email because for some reason I'm not receiving the full
> patch-set in my nvidia mail, a few comments below..
>
> > include/linux/if_bridge.h | 1 +
> > include/uapi/linux/if_link.h | 1 +
> > net/bridge/br_input.c | 10 +++++++++-
> > net/bridge/br_netlink.c | 6 +++++-
> > 4 files changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> > index 509e18c7e740..3aae023a9353 100644
> > --- a/include/linux/if_bridge.h
> > +++ b/include/linux/if_bridge.h
> > @@ -58,6 +58,7 @@ struct br_ip_list {
> > #define BR_MRP_LOST_CONT BIT(18)
> > #define BR_MRP_LOST_IN_CONT BIT(19)
> > #define BR_TX_FWD_OFFLOAD BIT(20)
> > +#define BR_PORT_LOCKED BIT(21)
> >
> > #define BR_DEFAULT_AGEING_TIME (300 * HZ)
> >
> > diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> > index 6218f93f5c1a..a45cc0a1f415 100644
> > --- a/include/uapi/linux/if_link.h
> > +++ b/include/uapi/linux/if_link.h
> > @@ -537,6 +537,7 @@ enum {
> > IFLA_BRPORT_MRP_IN_OPEN,
> > IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT,
> > IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
> > + IFLA_BRPORT_LOCKED,
> > __IFLA_BRPORT_MAX
> > };
> > #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
> > diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> > index b50382f957c1..469e3adbce07 100644
> > --- a/net/bridge/br_input.c
> > +++ b/net/bridge/br_input.c
> > @@ -69,6 +69,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> > struct net_bridge_port *p = br_port_get_rcu(skb->dev);
> > enum br_pkt_type pkt_type = BR_PKT_UNICAST;
> > struct net_bridge_fdb_entry *dst = NULL;
> > + struct net_bridge_fdb_entry *fdb_entry;
>
> move fdb_entry below to where it is used
>
> > struct net_bridge_mcast_port *pmctx;
> > struct net_bridge_mdb_entry *mdst;
> > bool local_rcv, mcast_hit = false;
> > @@ -81,6 +82,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> > if (!p || p->state == BR_STATE_DISABLED)
> > goto drop;
> >
> > + br = p->br;
> > +
>
> please drop the extra new line
>
> > brmctx = &p->br->multicast_ctx;
> > pmctx = &p->multicast_ctx;
> > state = p->state;
> > @@ -88,10 +91,15 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> > &state, &vlan))
> > goto out;
> >
> > + if (p->flags & BR_PORT_LOCKED) {
>
> fdb_entry should be defined in this scope only, and please rename it to something
> like fdb_src or just "src" as we already have "dst".
>
> > + fdb_entry = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
> > + if (!(fdb_entry && fdb_entry->dst == p))
>
> if (!fdb_entry || READ_ONCE(fdb_entry->dst) != p
I think we should also check that entry does not have 'BR_FDB_LOCAL'
set. These entries point at the bridge ports themselves, but do not
actually represent hosts behind the ports. Since they are automatically
populated, a malicious host can craft packets with SMAC of the bridge
port and bypass the check.
Assuming the above is true (didn't test), would be good to add a test
case for it in the selftest.
>
> > + goto drop;
> > + }
> > +
> > nbp_switchdev_frame_mark(p, skb);
> >
> > /* insert into forwarding database after filtering to avoid spoofing */
> > - br = p->br;
> > if (p->flags & BR_LEARNING)
> > br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
> >
> > diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> > index 2ff83d84230d..7d4432ca9a20 100644
> > --- a/net/bridge/br_netlink.c
> > +++ b/net/bridge/br_netlink.c
> > @@ -184,6 +184,7 @@ static inline size_t br_port_info_size(void)
> > + nla_total_size(1) /* IFLA_BRPORT_VLAN_TUNNEL */
> > + nla_total_size(1) /* IFLA_BRPORT_NEIGH_SUPPRESS */
> > + nla_total_size(1) /* IFLA_BRPORT_ISOLATED */
> > + + nla_total_size(1) /* IFLA_BRPORT_LOCKED */
> > + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_ROOT_ID */
> > + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_BRIDGE_ID */
> > + nla_total_size(sizeof(u16)) /* IFLA_BRPORT_DESIGNATED_PORT */
> > @@ -269,7 +270,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
> > BR_MRP_LOST_CONT)) ||
> > nla_put_u8(skb, IFLA_BRPORT_MRP_IN_OPEN,
> > !!(p->flags & BR_MRP_LOST_IN_CONT)) ||
> > - nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)))
> > + nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)) ||
> > + nla_put_u8(skb, IFLA_BRPORT_LOCKED, !!(p->flags & BR_PORT_LOCKED)))
> > return -EMSGSIZE;
> >
> > timerval = br_timer_value(&p->message_age_timer);
> > @@ -827,6 +829,7 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
> > [IFLA_BRPORT_GROUP_FWD_MASK] = { .type = NLA_U16 },
> > [IFLA_BRPORT_NEIGH_SUPPRESS] = { .type = NLA_U8 },
> > [IFLA_BRPORT_ISOLATED] = { .type = NLA_U8 },
> > + [IFLA_BRPORT_LOCKED] = { .type = NLA_U8 },
> > [IFLA_BRPORT_BACKUP_PORT] = { .type = NLA_U32 },
> > [IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT] = { .type = NLA_U32 },
> > };
> > @@ -893,6 +896,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
> > br_set_port_flag(p, tb, IFLA_BRPORT_VLAN_TUNNEL, BR_VLAN_TUNNEL);
> > br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_SUPPRESS, BR_NEIGH_SUPPRESS);
> > br_set_port_flag(p, tb, IFLA_BRPORT_ISOLATED, BR_ISOLATED);
> > + br_set_port_flag(p, tb, IFLA_BRPORT_LOCKED, BR_PORT_LOCKED);
> >
> > changed_mask = old_flags ^ p->flags;
> >
>
> Thanks,
> Nik
On 09/02/2022 15:05, Hans Schultz wrote:
> In a 802.1X scenario, clients connected to a bridge port shall not
> be allowed to have traffic forwarded until fully authenticated.
> A static fdb entry of the clients MAC address for the bridge port
> unlocks the client and allows bidirectional communication.
>
> This scenario is facilitated with setting the bridge port in locked
> mode, which is also supported by various switchcore chipsets.
>
> Signed-off-by: Hans Schultz <[email protected]>
> ---
Hi,
I'm writing from my private email because for some reason I'm not receiving the full
patch-set in my nvidia mail, a few comments below..
> include/linux/if_bridge.h | 1 +
> include/uapi/linux/if_link.h | 1 +
> net/bridge/br_input.c | 10 +++++++++-
> net/bridge/br_netlink.c | 6 +++++-
> 4 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> index 509e18c7e740..3aae023a9353 100644
> --- a/include/linux/if_bridge.h
> +++ b/include/linux/if_bridge.h
> @@ -58,6 +58,7 @@ struct br_ip_list {
> #define BR_MRP_LOST_CONT BIT(18)
> #define BR_MRP_LOST_IN_CONT BIT(19)
> #define BR_TX_FWD_OFFLOAD BIT(20)
> +#define BR_PORT_LOCKED BIT(21)
>
> #define BR_DEFAULT_AGEING_TIME (300 * HZ)
>
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 6218f93f5c1a..a45cc0a1f415 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -537,6 +537,7 @@ enum {
> IFLA_BRPORT_MRP_IN_OPEN,
> IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT,
> IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
> + IFLA_BRPORT_LOCKED,
> __IFLA_BRPORT_MAX
> };
> #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index b50382f957c1..469e3adbce07 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -69,6 +69,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> struct net_bridge_port *p = br_port_get_rcu(skb->dev);
> enum br_pkt_type pkt_type = BR_PKT_UNICAST;
> struct net_bridge_fdb_entry *dst = NULL;
> + struct net_bridge_fdb_entry *fdb_entry;
move fdb_entry below to where it is used
> struct net_bridge_mcast_port *pmctx;
> struct net_bridge_mdb_entry *mdst;
> bool local_rcv, mcast_hit = false;
> @@ -81,6 +82,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> if (!p || p->state == BR_STATE_DISABLED)
> goto drop;
>
> + br = p->br;
> +
please drop the extra new line
> brmctx = &p->br->multicast_ctx;
> pmctx = &p->multicast_ctx;
> state = p->state;
> @@ -88,10 +91,15 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
> &state, &vlan))
> goto out;
>
> + if (p->flags & BR_PORT_LOCKED) {
fdb_entry should be defined in this scope only, and please rename it to something
like fdb_src or just "src" as we already have "dst".
> + fdb_entry = br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
> + if (!(fdb_entry && fdb_entry->dst == p))
if (!fdb_entry || READ_ONCE(fdb_entry->dst) != p
> + goto drop;
> + }
> +
> nbp_switchdev_frame_mark(p, skb);
>
> /* insert into forwarding database after filtering to avoid spoofing */
> - br = p->br;
> if (p->flags & BR_LEARNING)
> br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
>
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 2ff83d84230d..7d4432ca9a20 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -184,6 +184,7 @@ static inline size_t br_port_info_size(void)
> + nla_total_size(1) /* IFLA_BRPORT_VLAN_TUNNEL */
> + nla_total_size(1) /* IFLA_BRPORT_NEIGH_SUPPRESS */
> + nla_total_size(1) /* IFLA_BRPORT_ISOLATED */
> + + nla_total_size(1) /* IFLA_BRPORT_LOCKED */
> + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_ROOT_ID */
> + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_BRIDGE_ID */
> + nla_total_size(sizeof(u16)) /* IFLA_BRPORT_DESIGNATED_PORT */
> @@ -269,7 +270,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
> BR_MRP_LOST_CONT)) ||
> nla_put_u8(skb, IFLA_BRPORT_MRP_IN_OPEN,
> !!(p->flags & BR_MRP_LOST_IN_CONT)) ||
> - nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)))
> + nla_put_u8(skb, IFLA_BRPORT_ISOLATED, !!(p->flags & BR_ISOLATED)) ||
> + nla_put_u8(skb, IFLA_BRPORT_LOCKED, !!(p->flags & BR_PORT_LOCKED)))
> return -EMSGSIZE;
>
> timerval = br_timer_value(&p->message_age_timer);
> @@ -827,6 +829,7 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
> [IFLA_BRPORT_GROUP_FWD_MASK] = { .type = NLA_U16 },
> [IFLA_BRPORT_NEIGH_SUPPRESS] = { .type = NLA_U8 },
> [IFLA_BRPORT_ISOLATED] = { .type = NLA_U8 },
> + [IFLA_BRPORT_LOCKED] = { .type = NLA_U8 },
> [IFLA_BRPORT_BACKUP_PORT] = { .type = NLA_U32 },
> [IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT] = { .type = NLA_U32 },
> };
> @@ -893,6 +896,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
> br_set_port_flag(p, tb, IFLA_BRPORT_VLAN_TUNNEL, BR_VLAN_TUNNEL);
> br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_SUPPRESS, BR_NEIGH_SUPPRESS);
> br_set_port_flag(p, tb, IFLA_BRPORT_ISOLATED, BR_ISOLATED);
> + br_set_port_flag(p, tb, IFLA_BRPORT_LOCKED, BR_PORT_LOCKED);
>
> changed_mask = old_flags ^ p->flags;
>
Thanks,
Nik