[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>

diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c
index a4f68e5b9c96c63d09f14c1b44ad3fcb986d7107..bf4a9f455d8ece68b1221d766c9a4611710245e9 100644 (file)
--- 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;