[S390] call home: fix local buffer usage in proc handler

Fix the size of the local buffer and use snprintf to prevent
further miscalculations. Also fix the usage of bitwise vs logic
operations.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c
index a4f68e5b9c96..bf4a9f455d8e 100644
--- a/drivers/s390/char/sclp_async.c
+++ b/drivers/s390/char/sclp_async.c
@@ -68,15 +68,14 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write,
 {
         unsigned long val;
         int len, rc;
-        char buf[2];
+        char buf[3];
 
-        if (!*count | (*ppos && !write)) {
+        if (!*count || (*ppos && !write)) {
                 *count = 0;
                 return 0;
         }
         if (!write) {
-                len =  sprintf(buf, "%d\n", callhome_enabled);
-                buf[len] = '\0';
+                len = snprintf(buf, sizeof(buf), "%d\n", callhome_enabled);
                 rc = copy_to_user(buffer, buf, sizeof(buf));
                 if (rc != 0)
                         return -EFAULT;