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Groups > linux.kernel > #1582750

[PATCH 4.9 24/32] net: introduce device min_header_len

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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Willem de Bruijn <willemb@google.com>


[ Upstream commit 217e6fa24ce28ec87fca8da93c9016cb78028612 ]

The stack must not pass packets to device drivers that are shorter
than the minimum link layer header length.

Previously, packet sockets would drop packets smaller than or equal
to dev->hard_header_len, but this has false positives. Zero length
payload is used over Ethernet. Other link layer protocols support
variable length headers. Support for validation of these protocols
removed the min length check for all protocols.

Introduce an explicit dev->min_header_len parameter and drop all
packets below this value. Initially, set it to non-zero only for
Ethernet and loopback. Other protocols can follow in a patch to
net-next.

Fixes: 9ed988cd5915 ("packet: validate variable length ll headers")
Reported-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/loopback.c    |    1 +
 include/linux/netdevice.h |    4 ++++
 net/ethernet/eth.c        |    1 +
 3 files changed, 6 insertions(+)

--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -164,6 +164,7 @@ static void loopback_setup(struct net_de
 {
 	dev->mtu		= 64 * 1024;
 	dev->hard_header_len	= ETH_HLEN;	/* 14	*/
+	dev->min_header_len	= ETH_HLEN;	/* 14	*/
 	dev->addr_len		= ETH_ALEN;	/* 6	*/
 	dev->type		= ARPHRD_LOOPBACK;	/* 0x0001*/
 	dev->flags		= IFF_LOOPBACK;
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1508,6 +1508,7 @@ enum netdev_priv_flags {
  *	@mtu:		Interface MTU value
  *	@type:		Interface hardware type
  *	@hard_header_len: Maximum hardware header length.
+ *	@min_header_len:  Minimum hardware header length
  *
  *	@needed_headroom: Extra headroom the hardware may need, but not in all
  *			  cases can this be guaranteed
@@ -1728,6 +1729,7 @@ struct net_device {
 	unsigned int		mtu;
 	unsigned short		type;
 	unsigned short		hard_header_len;
+	unsigned short		min_header_len;
 
 	unsigned short		needed_headroom;
 	unsigned short		needed_tailroom;
@@ -2783,6 +2785,8 @@ static inline bool dev_validate_header(c
 {
 	if (likely(len >= dev->hard_header_len))
 		return true;
+	if (len < dev->min_header_len)
+		return false;
 
 	if (capable(CAP_SYS_RAWIO)) {
 		memset(ll_header + len, 0, dev->hard_header_len - len);
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -356,6 +356,7 @@ void ether_setup(struct net_device *dev)
 	dev->header_ops		= &eth_header_ops;
 	dev->type		= ARPHRD_ETHER;
 	dev->hard_header_len 	= ETH_HLEN;
+	dev->min_header_len	= ETH_HLEN;
 	dev->mtu		= ETH_DATA_LEN;
 	dev->addr_len		= ETH_ALEN;
 	dev->tx_queue_len	= 1000;	/* Ethernet wants good queues */

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[PATCH 4.9 00/32] 4.9.11-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 08/32] net: use a work queue to defer net_disable_timestamp() work Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 27/32] net: dsa: Do not destroy invalid network devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 24/32] net: introduce device min_header_len Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 17/32] rtl8150: Use heap buffers for all register access Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 21/32] sctp: avoid BUG_ON on sctp_wait_for_sndbuf Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 04/32] ipv6: fix ip6_tnl_parse_tlv_enc_lim() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 07/32] stmmac: Discard masked flags in interrupt status register Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 05/32] ipv6: pointer math error in ip6_tnl_parse_tlv_enc_lim() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 32/32] net/mlx5: Dont unlock fte while still using it Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 09/32] ipv4: keep skb->dst around in presence of IP options Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 29/32] mld: do not remove mld souce list info when set link down Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 06/32] tcp: fix 0 divide in __tcp_select_window() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:00 +0100
  [PATCH 4.9 23/32] sit: fix a double free on error path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 03/32] net/sched: matchall: Fix configuration race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 19/32] catc: Use heap buffer for memory size test Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 22/32] lwtunnel: valid encap attr check should return 0 when lwtunnel is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 11/32] ip6_gre: fix ip6gre_err() invalid reads Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 15/32] macvtap: read vnet_hdr_size once Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 20/32] mlx4: Invoke softirqs after napi_reschedule Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 14/32] tun: read vnet_hdr_sz once Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 13/32] tcp: avoid infinite loop in tcp_splice_read() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 18/32] catc: Combine failure cleanup code in catc_probe() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 02/32] net/mlx5e: Fix update of hash function/key via ethtool Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 12/32] ipv6: tcp: add a missing tcp_v6_restore_cb() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 28/32] l2tp: do not use udp_ioctl() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 25/32] packet: round up linear to header len Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 10/32] netlabel: out of bound access in cipso_v4_validate() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  [PATCH 4.9 01/32] can: Fix kernel panic at security_sock_rcv_skb Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-16 19:10 +0100
  Re: [PATCH 4.9 00/32] 4.9.11-stable review Guenter Roeck <linux@roeck-us.net> - 2017-02-17 11:40 +0100
    Re: [PATCH 4.9 00/32] 4.9.11-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-17 19:20 +0100
  Re: [PATCH 4.9 00/32] 4.9.11-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-18 00:50 +0100
    Re: [PATCH 4.9 00/32] 4.9.11-stable review Kevin Hilman <khilman@baylibre.com> - 2017-02-20 23:40 +0100

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