Staging: bcm: Clean up code in ioctl: IOCTL_BCM_EEPROM_REGISTER_READ

This patch verifies two conditions before executing
a kmalloc call. First, it checks to see that
IoBuffer.OutputLength is not greater than an
unsigned short. If so, an invalid value may be
returned. The second change is a check to make
sure IoBuffer.OutputLength is not equal to
zero. Which simply keeps this code inline with
the other ioctl, IOCTL_BCM_REGISTER_READ_PRIVATE.

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index e110d0e..7cffbdd 100644 (file)
--- a/drivers/staging/bcm/Bcmchar.c
+++ b/drivers/staging/bcm/Bcmchar.c
@@ -306,7 +306,11 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                if (copy_from_user(&sRdmBuffer, IoBuffer.InputBuffer, IoBuffer.InputLength))
                        return -EFAULT;
 
-               /* FIXME: don't trust user supplied length */
+               if (IoBuffer.OutputLength > USHRT_MAX ||
+                       IoBuffer.OutputLength == 0) {
+                       return -EINVAL;
+               }
+
                temp_buff = kmalloc(IoBuffer.OutputLength, GFP_KERNEL);
                if (!temp_buff)
                        return STATUS_FAILURE;