path: root/drivers/net/loopback.c
diff options
authorWillem de Bruijn <willemb@google.com>2017-02-07 15:57:20 -0500
committerDavid S. Miller <davem@davemloft.net>2017-02-08 13:56:37 -0500
commit217e6fa24ce28ec87fca8da93c9016cb78028612 (patch)
tree1964e4821fd14a8255df061419fc2e8745bc92e7 /drivers/net/loopback.c
parentsit: fix a double free on error path (diff)
net: introduce device min_header_len
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>
Diffstat (limited to 'drivers/net/loopback.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 1e05b7c2d157..0844f8496413 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -164,6 +164,7 @@ static void loopback_setup(struct net_device *dev)
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;