net: netxen: correct sysfs bin attribute return code

If read() syscall requests unexpected number of bytes from "dimm" binary
attribute file, return EINVAL instead of EPERM.

At the same time pin down sysfs file size to the fixed
sizeof(struct netxen_dimm_cfg), which allows to exploit some missing
sanity checks from kernfs (file boundary checks vs offset etc.)

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
index e0c31e3947d1..6409a06bbdf6 100644
--- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
+++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
@@ -3025,9 +3025,9 @@ netxen_sysfs_read_dimm(struct file *filp, struct kobject *kobj,
         u8 dw, rows, cols, banks, ranks;
         u32 val;
 
-        if (size != sizeof(struct netxen_dimm_cfg)) {
+        if (size < attr->size) {
                 netdev_err(netdev, "Invalid size\n");
-                return -1;
+                return -EINVAL;
         }
 
         memset(&dimm, 0, sizeof(struct netxen_dimm_cfg));
@@ -3137,7 +3137,7 @@ out:
 
 static struct bin_attribute bin_attr_dimm = {
         .attr = { .name = "dimm", .mode = (S_IRUGO | S_IWUSR) },
-        .size = 0,
+        .size = sizeof(struct netxen_dimm_cfg),
         .read = netxen_sysfs_read_dimm,
 };