dm9601: don't do usb transfers of data on stack

dm_{read,write}() were doing USB transfers of data on stack, which isn't
allowed. Fix it by kmalloc'ing a temporary buffer.
Clean up the error handling for short transfers while we're at it.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 42 insertions, 10 deletions

diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index f7319d326912..78df2be8a728 100644
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -55,12 +55,28 @@
 
 static int dm_read(struct usbnet *dev, u8 reg, u16 length, void *data)
 {
+        void *buf;
+        int err = -ENOMEM;
+
         devdbg(dev, "dm_read() reg=0x%02x length=%d", reg, length);
-        return usb_control_msg(dev->udev,
-                               usb_rcvctrlpipe(dev->udev, 0),
-                               DM_READ_REGS,
-                               USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-                               0, reg, data, length, USB_CTRL_SET_TIMEOUT);
+
+        buf = kmalloc(length, GFP_KERNEL);
+        if (!buf)
+                goto out;
+
+        err = usb_control_msg(dev->udev,
+                              usb_rcvctrlpipe(dev->udev, 0),
+                              DM_READ_REGS,
+                              USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                              0, reg, buf, length, USB_CTRL_SET_TIMEOUT);
+        if (err == length)
+                memcpy(data, buf, length);
+        else if (err >= 0)
+                err = -EINVAL;
+        kfree(buf);
+
+ out:
+        return err;
 }
 
 static int dm_read_reg(struct usbnet *dev, u8 reg, u8 *value)
@@ -70,12 +86,28 @@ static int dm_read_reg(struct usbnet *dev, u8 reg, u8 *value)
 
 static int dm_write(struct usbnet *dev, u8 reg, u16 length, void *data)
 {
+        void *buf = NULL;
+        int err = -ENOMEM;
+
         devdbg(dev, "dm_write() reg=0x%02x, length=%d", reg, length);
-        return usb_control_msg(dev->udev,
-                               usb_sndctrlpipe(dev->udev, 0),
-                               DM_WRITE_REGS,
-                               USB_DIR_OUT | USB_TYPE_VENDOR |USB_RECIP_DEVICE,
-                               0, reg, data, length, USB_CTRL_SET_TIMEOUT);
+
+        if (data) {
+                buf = kmalloc(length, GFP_KERNEL);
+                if (!buf)
+                        goto out;
+                memcpy(buf, data, length);
+        }
+
+        err = usb_control_msg(dev->udev,
+                              usb_sndctrlpipe(dev->udev, 0),
+                              DM_WRITE_REGS,
+                              USB_DIR_OUT | USB_TYPE_VENDOR |USB_RECIP_DEVICE,
+                              0, reg, buf, length, USB_CTRL_SET_TIMEOUT);
+        kfree(buf);
+        if (err >= 0 && err < length)
+                err = -EINVAL;
+ out:
+        return err;
 }
 
 static int dm_write_reg(struct usbnet *dev, u8 reg, u8 value)