[media] media: stk1160: Avoid stack-allocated buffer for control URBs

Currently stk1160_read_reg() uses a stack-allocated char to get the
read control value. This is wrong because usb_control_msg() requires
a kmalloc-ed buffer.

This commit fixes such issue by kmalloc'ating a 1-byte buffer to receive
the read value.

While here, let's remove the urb_buf array which was meant for a similar
purpose, but never really used.

Cc: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: stable@vger.kernel.org      # for v3.7 and up
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

2 files changed, 9 insertions, 2 deletions

diff --git a/drivers/media/usb/stk1160/stk1160-core.c b/drivers/media/usb/stk1160/stk1160-core.c
index 34a26e0cfe77..03504dcf3c52 100644
--- a/drivers/media/usb/stk1160/stk1160-core.c
+++ b/drivers/media/usb/stk1160/stk1160-core.c
@@ -67,17 +67,25 @@ int stk1160_read_reg(struct stk1160 *dev, u16 reg, u8 *value)
 {
         int ret;
         int pipe = usb_rcvctrlpipe(dev->udev, 0);
+        u8 *buf;
 
         *value = 0;
+
+        buf = kmalloc(sizeof(u8), GFP_KERNEL);
+        if (!buf)
+                return -ENOMEM;
         ret = usb_control_msg(dev->udev, pipe, 0x00,
                         USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-                        0x00, reg, value, sizeof(u8), HZ);
+                        0x00, reg, buf, sizeof(u8), HZ);
         if (ret < 0) {
                 stk1160_err("read failed on reg 0x%x (%d)\n",
                         reg, ret);
+                kfree(buf);
                 return ret;
         }
 
+        *value = *buf;
+        kfree(buf);
         return 0;
 }
 
diff --git a/drivers/media/usb/stk1160/stk1160.h b/drivers/media/usb/stk1160/stk1160.h
index 05b05b160e1e..abdea484c998 100644
--- a/drivers/media/usb/stk1160/stk1160.h
+++ b/drivers/media/usb/stk1160/stk1160.h
@@ -143,7 +143,6 @@ struct stk1160 {
         int num_alt;
 
         struct stk1160_isoc_ctl isoc_ctl;
-        char urb_buf[255];       /* urb control msg buffer */
 
         /* frame properties */
         int width;                /* current frame width */