[PATCH net 2/3] s390/netiucv: improve checking of sysfs attribute buffer

[Ursula Braun]

High values are always wrong for netiucv's sysfs attribute "buffer".
But the current code does not detect values between 2**31 and 2**32
as invalid. Choosing type "unsigned int" for variable "bs1" and making
use of "kstrtouint()" improves the syntax checking for "buffer".

Signed-off-by: Ursula Braun <ubr...@linux.vnet.ibm.com>
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
---
 drivers/s390/net/netiucv.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index 88b6e9c..2f0f391 100644
--- a/drivers/s390/net/netiucv.c
+++ b/drivers/s390/net/netiucv.c
@@ -1563,21 +1563,21 @@ static ssize_t buffer_write (struct device *dev, struct 
device_attribute *attr,
 {
        struct netiucv_priv *priv = dev_get_drvdata(dev);
        struct net_device *ndev = priv->conn->netdev;
-       char         *e;
-       int          bs1;
+       unsigned int bs1;
+       int rc;
 
        IUCV_DBF_TEXT(trace, 3, __func__);
        if (count >= 39)
                return -EINVAL;
 
-       bs1 = simple_strtoul(buf, &e, 0);
+       rc = kstrtouint(buf, 0, &bs1);
 
-       if (e && (!isspace(*e))) {
-               IUCV_DBF_TEXT_(setup, 2, "buffer_write: invalid char %02x\n",
-                       *e);
+       if (rc == -EINVAL) {
+               IUCV_DBF_TEXT_(setup, 2, "buffer_write: invalid char %s\n",
+                       buf);
                return -EINVAL;
        }
-       if (bs1 > NETIUCV_BUFSIZE_MAX) {
+       if ((rc == -ERANGE) || (bs1 > NETIUCV_BUFSIZE_MAX)) {
                IUCV_DBF_TEXT_(setup, 2,
                        "buffer_write: buffer size %d too large\n",
                        bs1);
-- 
2.8.4