RE: [PATCH] rapidio/mport_cdev: NUL terminate some strings

From: alex.bou9
Date: Thu Jun 20 2019 - 21:08:52 EST


Acked-by: Alexandre Bounine <alex.bou9@xxxxxxxxx>

-----Original Message-----
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Sent: Wednesday, May 29, 2019 7:06 AM
To: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>
Cc: Alexandre Bounine <alex.bou9@xxxxxxxxx>; Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx>; Ira Weiny <ira.weiny@xxxxxxxxx>;
linux-kernel@xxxxxxxxxxxxxxx; kernel-janitors@xxxxxxxxxxxxxxx
Subject: [PATCH] rapidio/mport_cdev: NUL terminate some strings

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.

Fixes: e8de370188d0 ("rapidio: add mport char device driver")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
drivers/rapidio/devices/rio_mport_cdev.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/rapidio/devices/rio_mport_cdev.c
b/drivers/rapidio/devices/rio_mport_cdev.c
index 4a4a75fa26d5..3440b3e8e578 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -1690,6 +1690,7 @@ 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);
@@ -1821,6 +1822,7 @@ 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;

--
2.20.1