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.

---
 drivers/rapidio/devices/rio_mport_cdev.c | 2 ++
 1 file changed, 2 insertions(+)

index 4a4a75fa26d5..3440b3e8e578 100644
@@ -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

-----Original Message-----
From: Dan Carpenter <[email protected]>
Sent: Wednesday, May 29, 2019 7:06 AM
To: Matt Porter <[email protected]>
Cc: Alexandre Bounine <[email protected]>; Andrew Morton <[email protected]>; Ira Weiny <[email protected]>; [email protected]; [email protected]
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.

---
 drivers/rapidio/devices/rio_mport_cdev.c | 2 ++
 1 file changed, 2 insertions(+)

b/drivers/rapidio/devices/rio_mport_cdev.c
index 4a4a75fa26d5..3440b3e8e578 100644

@@ -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