Patch "crypto: s5p-sss - Close possible race for completed requests" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

crypto: s5p-sss - Close possible race for completed requests

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
crypto-s5p-sss-close-possible-race-for-completed-requests.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Krzysztof Kozlowski <[email protected]>
Date: Fri, 17 Mar 2017 16:49:19 +0200
Subject: crypto: s5p-sss - Close possible race for completed requests

From: Krzysztof Kozlowski <[email protected]>

commit 42d5c176b76e190a4a3e0dfeffdae661755955b6 upstream.

Driver is capable of handling only one request at a time and it stores it in its state container struct s5p_aes_dev. This stored request must be protected between concurrent invocations (e.g. completing current request and scheduling new one). Combination of lock and "busy" field is used for that purpose.

When "busy" field is true, the driver will not accept new request thus it will not overwrite currently handled data.

However commit 28b62b145868 ("crypto: s5p-sss - Fix spinlock recursion on LRW(AES)") moved some of the write to "busy" field out of a lock protected critical section. This might lead to potential race between completing current request and scheduling a new one. Effectively the request completion might try to operate on new crypto request.

---
 drivers/crypto/s5p-sss.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -287,7 +287,6 @@ static void s5p_sg_done(struct s5p_aes_d
 static void s5p_aes_complete(struct s5p_aes_dev *dev, int err)
 {
 	dev->req->base.complete(&dev->req->base, err);
-	dev->busy = false;
 }
 
 static void s5p_unset_outdata(struct s5p_aes_dev *dev)

@@ -462,7 +461,7 @@ static irqreturn_t s5p_aes_interrupt(int
 		spin_unlock_irqrestore(&dev->lock, flags);
 
 		s5p_aes_complete(dev, 0);
-		dev->busy = true;
+		/* Device is still busy */
 		tasklet_schedule(&dev->tasklet);
 	} else {
 		/*

@@ -483,6 +482,7 @@ static irqreturn_t s5p_aes_interrupt(int
 
 error:
 	s5p_sg_done(dev);
+	dev->busy = false;
 	spin_unlock_irqrestore(&dev->lock, flags);
 	s5p_aes_complete(dev, err);
 

@@ -634,6 +634,7 @@ outdata_error:
 
 indata_error:
 	s5p_sg_done(dev);
+	dev->busy = false;
 	spin_unlock_irqrestore(&dev->lock, flags);
 	s5p_aes_complete(dev, err);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/crypto-s5p-sss-close-possible-race-for-completed-requests.patch