[patch v2] libertas: potential oops in debugfs

Dan Carpenter
2013-10-30T17:16:35Z

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 <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

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++) {