If we do a zero size allocation then it will oops.  Also we can't be
sure the user passes us a NUL terminated string so I've added a
terminator.

This code can only be triggered by root.

Reported-by: Nico Golde <[email protected]>
Reported-by: Fabian Yamaguchi <[email protected]>
Signed-off-by: Dan Carpenter <[email protected]>

diff --git a/drivers/net/wireless/libertas/debugfs.c 
b/drivers/net/wireless/libertas/debugfs.c
index 668dd27..1917348 100644
--- a/drivers/net/wireless/libertas/debugfs.c
+++ b/drivers/net/wireless/libertas/debugfs.c
@@ -913,7 +913,10 @@ static ssize_t lbs_debugfs_write(struct file *f, const 
char __user *buf,
        char *p2;
        struct debug_data *d = f->private_data;
 
-       pdata = kmalloc(cnt, GFP_KERNEL);
+       if (cnt == 0)
+               return 0;
+
+       pdata = kmalloc(cnt + 1, GFP_KERNEL);
        if (pdata == NULL)
                return 0;
 
@@ -922,6 +925,7 @@ static ssize_t lbs_debugfs_write(struct file *f, const char 
__user *buf,
                kfree(pdata);
                return 0;
        }
+       pdata[cnt] = '\0';
 
        p0 = pdata;
        for (i = 0; i < num_of_items; i++) {
--
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