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

BugLink: http://bugs.launchpad.net/bugs/1692898
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.

Fixes: 28b62b145868 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
index 4721d50c4628fc0cd0d46b8b7b108eca28220501..cc8f89a86ca23fe54678098dbcea456c7812c003 100644 (file)
--- a/drivers/crypto/s5p-sss.c
+++ b/drivers/crypto/s5p-sss.c
@@ -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);
 }