[PATCH 10/44] uio: fix allocating minor id for uio device

[Greg Kroah-Hartman]

From: Hillf Danton <dhillf@xxxxxxxxx>

The number of uio devices that could be used should be less than
UIO_MAX_DEVICES by design, and this work guards any cases in which id
more than UIO_MAX_DEVICES is utilized.

Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
Signed-off-by: Hans J. Koch <hjk@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/uio/uio.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 10a029b..d2efe82 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -381,7 +381,13 @@ static int uio_get_minor(struct uio_device *idev)
 			retval = -ENOMEM;
 		goto exit;
 	}
-	idev->minor = id & MAX_ID_MASK;
+	if (id < UIO_MAX_DEVICES) {
+		idev->minor = id;
+	} else {
+		dev_err(idev->dev, "too many uio devices\n");
+		retval = -EINVAL;
+		idr_remove(&uio_idr, id);
+	}
 exit:
 	mutex_unlock(&minor_lock);
 	return retval;
-- 
1.7.4.2

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