Commit 42d5c176 authored Mar 17, 2017 by Krzysztof Kozlowski Committed by Herbert Xu Mar 24, 2017

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



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 28b62b14 ("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.

Cc: <stable@vger.kernel.org> # v4.10.x
Fixes: 28b62b14 ("crypto: s5p-sss - Fix spinlock recursion on LRW(AES)")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent b189817c

drivers/crypto/s5p-sss.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -287,7 +287,6 @@ static void s5p_sg_done(struct s5p_aes_dev *dev)
		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 irq, void *dev_id)
		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 irq, void *dev_id)

		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);
		}

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