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authorXie He <xie.he.0141@gmail.com>2020-07-06 03:45:21 +0300
committerDavid S. Miller <davem@davemloft.net>2020-07-06 22:16:21 +0300
commit9dc829a135fb5927f1519de11286e2bbb79f5b66 (patch)
tree45c4bd493bec432250eb48c4fb931fdb2d38f212 /drivers
parent0f57a1e522f413e87852e632f55de4723e511939 (diff)
downloadlinux-9dc829a135fb5927f1519de11286e2bbb79f5b66.tar.xz
drivers/net/wan/lapbether: Fixed the value of hard_header_len
When this driver transmits data, first this driver will remove a pseudo header of 1 byte, then the lapb module will prepend the LAPB header of 2 or 3 bytes, then this driver will prepend a length field of 2 bytes, then the underlying Ethernet device will prepend its own header. So, the header length required should be: -1 + 3 + 2 + "the header length needed by the underlying device". This patch fixes kernel panic when this driver is used with AF_PACKET SOCK_DGRAM sockets. Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/wan/lapbether.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index e30d91a38cfb..284832314f31 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -303,7 +303,6 @@ static void lapbeth_setup(struct net_device *dev)
dev->netdev_ops = &lapbeth_netdev_ops;
dev->needs_free_netdev = true;
dev->type = ARPHRD_X25;
- dev->hard_header_len = 3;
dev->mtu = 1000;
dev->addr_len = 0;
}
@@ -324,6 +323,14 @@ static int lapbeth_new_device(struct net_device *dev)
if (!ndev)
goto out;
+ /* When transmitting data:
+ * first this driver removes a pseudo header of 1 byte,
+ * then the lapb module prepends an LAPB header of at most 3 bytes,
+ * then this driver prepends a length field of 2 bytes,
+ * then the underlying Ethernet device prepends its own header.
+ */
+ ndev->hard_header_len = -1 + 3 + 2 + dev->hard_header_len;
+
lapbeth = netdev_priv(ndev);
lapbeth->axdev = ndev;