[S390] handle incorrect values when writing to dasd sysfs attributes.

When writing to dasd attributes (e.g. readonly), all values besides '1'
are handled like '0'.
Other sysfs-attributes like 'online' are checking for '1' and for '0'
and do not accept other values. Therefore enhanced checking and error
handling in dasd_devmap attribute store functions.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 29 insertions, 14 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 91cf971f0652..b5e70c523921 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -684,21 +684,26 @@ dasd_ro_store(struct device *dev, struct device_attribute *attr,
               const char *buf, size_t count)
 {
         struct dasd_devmap *devmap;
-        int ro_flag;
+        int val;
+        char *endp;
 
         devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
         if (IS_ERR(devmap))
                 return PTR_ERR(devmap);
-        ro_flag = buf[0] == '1';
+
+        val = simple_strtoul(buf, &endp, 0);
+        if (((endp + 1) < (buf + count)) || (val > 1))
+                return -EINVAL;
+
         spin_lock(&dasd_devmap_lock);
-        if (ro_flag)
+        if (val)
                 devmap->features |= DASD_FEATURE_READONLY;
         else
                 devmap->features &= ~DASD_FEATURE_READONLY;
         if (devmap->device)
                 devmap->device->features = devmap->features;
         if (devmap->device && devmap->device->gdp)
-                set_disk_ro(devmap->device->gdp, ro_flag);
+                set_disk_ro(devmap->device->gdp, val);
         spin_unlock(&dasd_devmap_lock);
         return count;
 }
@@ -729,17 +734,22 @@ dasd_use_diag_store(struct device *dev, struct device_attribute *attr,
 {
         struct dasd_devmap *devmap;
         ssize_t rc;
-        int use_diag;
+        int val;
+        char *endp;
 
         devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
         if (IS_ERR(devmap))
                 return PTR_ERR(devmap);
-        use_diag = buf[0] == '1';
+
+        val = simple_strtoul(buf, &endp, 0);
+        if (((endp + 1) < (buf + count)) || (val > 1))
+                return -EINVAL;
+
         spin_lock(&dasd_devmap_lock);
         /* Changing diag discipline flag is only allowed in offline state. */
         rc = count;
         if (!devmap->device) {
-                if (use_diag)
+                if (val)
                         devmap->features |= DASD_FEATURE_USEDIAG;
                 else
                         devmap->features &= ~DASD_FEATURE_USEDIAG;
@@ -854,20 +864,25 @@ dasd_eer_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
 {
         struct dasd_devmap *devmap;
-        int rc;
+        int val, rc;
+        char *endp;
 
         devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
         if (IS_ERR(devmap))
                 return PTR_ERR(devmap);
         if (!devmap->device)
-                return count;
-        if (buf[0] == '1') {
+                return -ENODEV;
+
+        val = simple_strtoul(buf, &endp, 0);
+        if (((endp + 1) < (buf + count)) || (val > 1))
+                return -EINVAL;
+
+        rc = count;
+        if (val)
                 rc = dasd_eer_enable(devmap->device);
-                if (rc)
-                        return rc;
-        } else
+        else
                 dasd_eer_disable(devmap->device);
-        return count;
+        return rc;
 }
 
 static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);