Thread (10 messages) 10 messages, 3 authors, 2021-02-18
STALE1982d
Revisions (5)
  1. v4 [diff vs current]
  2. v5 [diff vs current]
  3. v6 [diff vs current]
  4. v7 current
  5. v8 [diff vs current]

[PATCH v7 bpf-next 2/6] netdevice: check for net_device::priv_flags bitfield overflow

From: Alexander Lobakin <hidden>
Date: 2021-02-17 12:05:44
Also in: lkml, netdev
Subsystem: networking drivers, networking [general], the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

We almost ran out of unsigned int bitwidth. Define priv flags and
check for potential overflow in the fashion of netdev_features_t.
Defined this way, priv_flags can be easily expanded later with
just changing its typedef.

Signed-off-by: Alexander Lobakin <redacted>
Reported-by: kernel test robot <redacted> # Inverted assert condition
---
 include/linux/netdevice.h | 199 ++++++++++++++++++++------------------
 1 file changed, 105 insertions(+), 94 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3b6f82c2c271..2c1a642ecdc0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1483,107 +1483,118 @@ struct net_device_ops {
  *
  * You should have a pretty good reason to be extending these flags.
  *
- * @IFF_802_1Q_VLAN: 802.1Q VLAN device
- * @IFF_EBRIDGE: Ethernet bridging device
- * @IFF_BONDING: bonding master or slave
- * @IFF_ISATAP: ISATAP interface (RFC4214)
- * @IFF_WAN_HDLC: WAN HDLC device
- * @IFF_XMIT_DST_RELEASE: dev_hard_start_xmit() is allowed to
+ * @IFF_802_1Q_VLAN_BIT: 802.1Q VLAN device
+ * @IFF_EBRIDGE_BIT: Ethernet bridging device
+ * @IFF_BONDING_BIT: bonding master or slave
+ * @IFF_ISATAP_BIT: ISATAP interface (RFC4214)
+ * @IFF_WAN_HDLC_BIT: WAN HDLC device
+ * @IFF_XMIT_DST_RELEASE_BIT: dev_hard_start_xmit() is allowed to
  *	release skb->dst
- * @IFF_DONT_BRIDGE: disallow bridging this ether dev
- * @IFF_DISABLE_NETPOLL: disable netpoll at run-time
- * @IFF_MACVLAN_PORT: device used as macvlan port
- * @IFF_BRIDGE_PORT: device used as bridge port
- * @IFF_OVS_DATAPATH: device used as Open vSwitch datapath port
- * @IFF_TX_SKB_SHARING: The interface supports sharing skbs on transmit
- * @IFF_UNICAST_FLT: Supports unicast filtering
- * @IFF_TEAM_PORT: device used as team port
- * @IFF_SUPP_NOFCS: device supports sending custom FCS
- * @IFF_LIVE_ADDR_CHANGE: device supports hardware address
+ * @IFF_DONT_BRIDGE_BIT: disallow bridging this ether dev
+ * @IFF_DISABLE_NETPOLL_BIT: disable netpoll at run-time
+ * @IFF_MACVLAN_PORT_BIT: device used as macvlan port
+ * @IFF_BRIDGE_PORT_BIT: device used as bridge port
+ * @IFF_OVS_DATAPATH_BIT: device used as Open vSwitch datapath port
+ * @IFF_TX_SKB_SHARING_BIT: The interface supports sharing skbs on transmit
+ * @IFF_UNICAST_FLT_BIT: Supports unicast filtering
+ * @IFF_TEAM_PORT_BIT: device used as team port
+ * @IFF_SUPP_NOFCS_BIT: device supports sending custom FCS
+ * @IFF_LIVE_ADDR_CHANGE_BIT: device supports hardware address
  *	change when it's running
- * @IFF_MACVLAN: Macvlan device
- * @IFF_XMIT_DST_RELEASE_PERM: IFF_XMIT_DST_RELEASE not taking into account
+ * @IFF_MACVLAN_BIT: Macvlan device
+ * @IFF_XMIT_DST_RELEASE_PERM_BIT: IFF_XMIT_DST_RELEASE not taking into account
  *	underlying stacked devices
- * @IFF_L3MDEV_MASTER: device is an L3 master device
- * @IFF_NO_QUEUE: device can run without qdisc attached
- * @IFF_OPENVSWITCH: device is a Open vSwitch master
- * @IFF_L3MDEV_SLAVE: device is enslaved to an L3 master device
- * @IFF_TEAM: device is a team device
- * @IFF_RXFH_CONFIGURED: device has had Rx Flow indirection table configured
- * @IFF_PHONY_HEADROOM: the headroom value is controlled by an external
+ * @IFF_L3MDEV_MASTER_BIT: device is an L3 master device
+ * @IFF_NO_QUEUE_BIT: device can run without qdisc attached
+ * @IFF_OPENVSWITCH_BIT: device is a Open vSwitch master
+ * @IFF_L3MDEV_SLAVE_BIT: device is enslaved to an L3 master device
+ * @IFF_TEAM_BIT: device is a team device
+ * @IFF_RXFH_CONFIGURED_BIT: device has had Rx Flow indirection table configured
+ * @IFF_PHONY_HEADROOM_BIT: the headroom value is controlled by an external
  *	entity (i.e. the master device for bridged veth)
- * @IFF_MACSEC: device is a MACsec device
- * @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook
- * @IFF_FAILOVER: device is a failover master device
- * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
- * @IFF_L3MDEV_RX_HANDLER: only invoke the rx handler of L3 master device
- * @IFF_LIVE_RENAME_OK: rename is allowed while device is up and running
+ * @IFF_MACSEC_BIT: device is a MACsec device
+ * @IFF_NO_RX_HANDLER_BIT: device doesn't support the rx_handler hook
+ * @IFF_FAILOVER_BIT: device is a failover master device
+ * @IFF_FAILOVER_SLAVE_BIT: device is lower dev of a failover master device
+ * @IFF_L3MDEV_RX_HANDLER_BIT: only invoke the rx handler of L3 master device
+ * @IFF_LIVE_RENAME_OK_BIT: rename is allowed while device is up and running
+ *
+ * @NETDEV_PRIV_FLAG_COUNT: total priv flags count
  */
 enum netdev_priv_flags {
-	IFF_802_1Q_VLAN			= 1<<0,
-	IFF_EBRIDGE			= 1<<1,
-	IFF_BONDING			= 1<<2,
-	IFF_ISATAP			= 1<<3,
-	IFF_WAN_HDLC			= 1<<4,
-	IFF_XMIT_DST_RELEASE		= 1<<5,
-	IFF_DONT_BRIDGE			= 1<<6,
-	IFF_DISABLE_NETPOLL		= 1<<7,
-	IFF_MACVLAN_PORT		= 1<<8,
-	IFF_BRIDGE_PORT			= 1<<9,
-	IFF_OVS_DATAPATH		= 1<<10,
-	IFF_TX_SKB_SHARING		= 1<<11,
-	IFF_UNICAST_FLT			= 1<<12,
-	IFF_TEAM_PORT			= 1<<13,
-	IFF_SUPP_NOFCS			= 1<<14,
-	IFF_LIVE_ADDR_CHANGE		= 1<<15,
-	IFF_MACVLAN			= 1<<16,
-	IFF_XMIT_DST_RELEASE_PERM	= 1<<17,
-	IFF_L3MDEV_MASTER		= 1<<18,
-	IFF_NO_QUEUE			= 1<<19,
-	IFF_OPENVSWITCH			= 1<<20,
-	IFF_L3MDEV_SLAVE		= 1<<21,
-	IFF_TEAM			= 1<<22,
-	IFF_RXFH_CONFIGURED		= 1<<23,
-	IFF_PHONY_HEADROOM		= 1<<24,
-	IFF_MACSEC			= 1<<25,
-	IFF_NO_RX_HANDLER		= 1<<26,
-	IFF_FAILOVER			= 1<<27,
-	IFF_FAILOVER_SLAVE		= 1<<28,
-	IFF_L3MDEV_RX_HANDLER		= 1<<29,
-	IFF_LIVE_RENAME_OK		= 1<<30,
+	IFF_802_1Q_VLAN_BIT,
+	IFF_EBRIDGE_BIT,
+	IFF_BONDING_BIT,
+	IFF_ISATAP_BIT,
+	IFF_WAN_HDLC_BIT,
+	IFF_XMIT_DST_RELEASE_BIT,
+	IFF_DONT_BRIDGE_BIT,
+	IFF_DISABLE_NETPOLL_BIT,
+	IFF_MACVLAN_PORT_BIT,
+	IFF_BRIDGE_PORT_BIT,
+	IFF_OVS_DATAPATH_BIT,
+	IFF_TX_SKB_SHARING_BIT,
+	IFF_UNICAST_FLT_BIT,
+	IFF_TEAM_PORT_BIT,
+	IFF_SUPP_NOFCS_BIT,
+	IFF_LIVE_ADDR_CHANGE_BIT,
+	IFF_MACVLAN_BIT,
+	IFF_XMIT_DST_RELEASE_PERM_BIT,
+	IFF_L3MDEV_MASTER_BIT,
+	IFF_NO_QUEUE_BIT,
+	IFF_OPENVSWITCH_BIT,
+	IFF_L3MDEV_SLAVE_BIT,
+	IFF_TEAM_BIT,
+	IFF_RXFH_CONFIGURED_BIT,
+	IFF_PHONY_HEADROOM_BIT,
+	IFF_MACSEC_BIT,
+	IFF_NO_RX_HANDLER_BIT,
+	IFF_FAILOVER_BIT,
+	IFF_FAILOVER_SLAVE_BIT,
+	IFF_L3MDEV_RX_HANDLER_BIT,
+	IFF_LIVE_RENAME_OK_BIT,
+
+	NETDEV_PRIV_FLAG_COUNT,
 };
 
-#define IFF_802_1Q_VLAN			IFF_802_1Q_VLAN
-#define IFF_EBRIDGE			IFF_EBRIDGE
-#define IFF_BONDING			IFF_BONDING
-#define IFF_ISATAP			IFF_ISATAP
-#define IFF_WAN_HDLC			IFF_WAN_HDLC
-#define IFF_XMIT_DST_RELEASE		IFF_XMIT_DST_RELEASE
-#define IFF_DONT_BRIDGE			IFF_DONT_BRIDGE
-#define IFF_DISABLE_NETPOLL		IFF_DISABLE_NETPOLL
-#define IFF_MACVLAN_PORT		IFF_MACVLAN_PORT
-#define IFF_BRIDGE_PORT			IFF_BRIDGE_PORT
-#define IFF_OVS_DATAPATH		IFF_OVS_DATAPATH
-#define IFF_TX_SKB_SHARING		IFF_TX_SKB_SHARING
-#define IFF_UNICAST_FLT			IFF_UNICAST_FLT
-#define IFF_TEAM_PORT			IFF_TEAM_PORT
-#define IFF_SUPP_NOFCS			IFF_SUPP_NOFCS
-#define IFF_LIVE_ADDR_CHANGE		IFF_LIVE_ADDR_CHANGE
-#define IFF_MACVLAN			IFF_MACVLAN
-#define IFF_XMIT_DST_RELEASE_PERM	IFF_XMIT_DST_RELEASE_PERM
-#define IFF_L3MDEV_MASTER		IFF_L3MDEV_MASTER
-#define IFF_NO_QUEUE			IFF_NO_QUEUE
-#define IFF_OPENVSWITCH			IFF_OPENVSWITCH
-#define IFF_L3MDEV_SLAVE		IFF_L3MDEV_SLAVE
-#define IFF_TEAM			IFF_TEAM
-#define IFF_RXFH_CONFIGURED		IFF_RXFH_CONFIGURED
-#define IFF_PHONY_HEADROOM		IFF_PHONY_HEADROOM
-#define IFF_MACSEC			IFF_MACSEC
-#define IFF_NO_RX_HANDLER		IFF_NO_RX_HANDLER
-#define IFF_FAILOVER			IFF_FAILOVER
-#define IFF_FAILOVER_SLAVE		IFF_FAILOVER_SLAVE
-#define IFF_L3MDEV_RX_HANDLER		IFF_L3MDEV_RX_HANDLER
-#define IFF_LIVE_RENAME_OK		IFF_LIVE_RENAME_OK
+typedef u32 netdev_priv_flags_t;
+static_assert(sizeof(netdev_priv_flags_t) * BITS_PER_BYTE >=
+	      NETDEV_PRIV_FLAG_COUNT);
+
+#define __IFF_BIT(bit)			((netdev_priv_flags_t)1 << (bit))
+#define __IFF(name)			__IFF_BIT(IFF_##name##_BIT)
+
+#define IFF_802_1Q_VLAN			__IFF(802_1Q_VLAN)
+#define IFF_EBRIDGE			__IFF(EBRIDGE)
+#define IFF_BONDING			__IFF(BONDING)
+#define IFF_ISATAP			__IFF(ISATAP)
+#define IFF_WAN_HDLC			__IFF(WAN_HDLC)
+#define IFF_XMIT_DST_RELEASE		__IFF(XMIT_DST_RELEASE)
+#define IFF_DONT_BRIDGE			__IFF(DONT_BRIDGE)
+#define IFF_DISABLE_NETPOLL		__IFF(DISABLE_NETPOLL)
+#define IFF_MACVLAN_PORT		__IFF(MACVLAN_PORT)
+#define IFF_BRIDGE_PORT			__IFF(BRIDGE_PORT)
+#define IFF_OVS_DATAPATH		__IFF(OVS_DATAPATH)
+#define IFF_TX_SKB_SHARING		__IFF(TX_SKB_SHARING)
+#define IFF_UNICAST_FLT			__IFF(UNICAST_FLT)
+#define IFF_TEAM_PORT			__IFF(TEAM_PORT)
+#define IFF_SUPP_NOFCS			__IFF(SUPP_NOFCS)
+#define IFF_LIVE_ADDR_CHANGE		__IFF(LIVE_ADDR_CHANGE)
+#define IFF_MACVLAN			__IFF(MACVLAN)
+#define IFF_XMIT_DST_RELEASE_PERM	__IFF(XMIT_DST_RELEASE_PERM)
+#define IFF_L3MDEV_MASTER		__IFF(L3MDEV_MASTER)
+#define IFF_NO_QUEUE			__IFF(NO_QUEUE)
+#define IFF_OPENVSWITCH			__IFF(OPENVSWITCH)
+#define IFF_L3MDEV_SLAVE		__IFF(L3MDEV_SLAVE)
+#define IFF_TEAM			__IFF(TEAM)
+#define IFF_RXFH_CONFIGURED		__IFF(RXFH_CONFIGURED)
+#define IFF_PHONY_HEADROOM		__IFF(PHONY_HEADROOM)
+#define IFF_MACSEC			__IFF(MACSEC)
+#define IFF_NO_RX_HANDLER		__IFF(NO_RX_HANDLER)
+#define IFF_FAILOVER			__IFF(FAILOVER)
+#define IFF_FAILOVER_SLAVE		__IFF(FAILOVER_SLAVE)
+#define IFF_L3MDEV_RX_HANDLER		__IFF(L3MDEV_RX_HANDLER)
+#define IFF_LIVE_RENAME_OK		__IFF(LIVE_RENAME_OK)
 
 /**
  *	struct net_device - The DEVICE structure.
@@ -1876,7 +1887,7 @@ struct net_device {
 
 	/* Read-mostly cache-line for fast-path access */
 	unsigned int		flags;
-	unsigned int		priv_flags;
+	netdev_priv_flags_t	priv_flags;
 	const struct net_device_ops *netdev_ops;
 	int			ifindex;
 	unsigned short		gflags;
-- 
2.30.1

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