V4L/DVB (5163): Add checks for CAP_SYS_ADMIN to VIDIOC_DBG_G_REGISTER

Before, root privileges were only needed to set hardware registers, not
to read them.  On some hardware, reading from the wrong place at the
wrong time can hang the machine.  So, to be consistent, root privileges
are required to read registers on all hardware.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 4 insertions, 12 deletions

diff --git a/drivers/media/video/upd64031a.c b/drivers/media/video/upd64031a.c
index 0eee82ba52bc..b3b5fd536dc3 100644
--- a/drivers/media/video/upd64031a.c
+++ b/drivers/media/video/upd64031a.c
@@ -163,26 +163,18 @@ static int upd64031a_command(struct i2c_client *client, unsigned int cmd, void *
 
 #ifdef CONFIG_VIDEO_ADV_DEBUG
         case VIDIOC_DBG_G_REGISTER:
-        {
-                struct v4l2_register *reg = arg;
-
-                if (reg->i2c_id != I2C_DRIVERID_UPD64031A)
-                        return -EINVAL;
-                reg->val = upd64031a_read(client, reg->reg & 0xff);
-                break;
-        }
-
         case VIDIOC_DBG_S_REGISTER:
         {
                 struct v4l2_register *reg = arg;
-                u8 addr = reg->reg & 0xff;
-                u8 val = reg->val & 0xff;
 
                 if (reg->i2c_id != I2C_DRIVERID_UPD64031A)
                         return -EINVAL;
                 if (!capable(CAP_SYS_ADMIN))
                         return -EPERM;
-                upd64031a_write(client, addr, val);
+                if (cmd == VIDIOC_DBG_G_REGISTER)
+                        reg->val = upd64031a_read(client, reg->reg & 0xff);
+                else
+                        upd64031a_write(client, reg->reg & 0xff, reg->val & 0xff);
                 break;
         }
 #endif