drivers/rapidio/devices/rio_mport_cdev.c: NUL terminate some strings

[ Upstream commit 156e0b1a8112b76e351684ac948c59757037ac36 ]

The dev_info.name[] array has space for RIO_MAX_DEVNAME_SZ + 1
characters.  But the problem here is that we don't ensure that the user
put a NUL terminator on the end of the string.  It could lead to an out
of bounds read.

Link: http://lkml.kernel.org/r/20190529110601.GB19119@mwanda
Fixes: e8de370188d0 ("rapidio: add mport char device driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index f32fc70..28c45db 100644 (file)
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -1743,6 +1743,7 @@ static int rio_mport_add_riodev(struct mport_cdev_priv *priv,
 
        if (copy_from_user(&dev_info, arg, sizeof(dev_info)))
                return -EFAULT;
+       dev_info.name[sizeof(dev_info.name) - 1] = '\0';
 
        rmcd_debug(RDEV, "name:%s ct:0x%x did:0x%x hc:0x%x", dev_info.name,
                   dev_info.comptag, dev_info.destid, dev_info.hopcount);
@@ -1874,6 +1875,7 @@ static int rio_mport_del_riodev(struct mport_cdev_priv *priv, void __user *arg)
 
        if (copy_from_user(&dev_info, arg, sizeof(dev_info)))
                return -EFAULT;
+       dev_info.name[sizeof(dev_info.name) - 1] = '\0';
 
        mport = priv->md->mport;