[PATCH 3.12 140/181] media: stk1160: Avoid stack-allocated buffer for control URBs

Jiri Slaby
2014-06-30T12:42:40Z

From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 85ac1a1772bb41da895bad83a81f6a62c8f293f6 upstream.

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>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/media/usb/stk1160/stk1160-core.c | 10 +++++++++-
drivers/media/usb/stk1160/stk1160.h | 1 -
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 */
--
2.0.0