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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Alexandre Bounine <alex.bou9@gmail.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 34/74] drivers/rapidio/devices/rio_mport_cdev.c: NUL terminate some strings
Date:   Mon,  5 Aug 2019 15:02:47 +0200
Message-Id: <20190805124938.547554946@linuxfoundation.org>
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[ 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>
---
 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 cbe467ff1aba9..fa0bbda4b3f2e 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -1688,6 +1688,7 @@ 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);
@@ -1819,6 +1820,7 @@ 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