[PATCH 3.18 11/45] crypto: gcm - wait for crypto op not signal safe

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gilad Ben-Yossef <gilad@benyossef.com>

commit f3ad587070d6bd961ab942b3fd7a85d00dfc934b upstream.

crypto_gcm_setkey() was using wait_for_completion_interruptible() to
wait for completion of async crypto op but if a signal occurs it
may return before DMA ops of HW crypto provider finish, thus
corrupting the data buffer that is kfree'ed in this case.

Resolve this by using wait_for_completion() instead.

Reported-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/gcm.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -146,10 +146,8 @@ static int crypto_gcm_setkey(struct cryp
 
 	err = crypto_ablkcipher_encrypt(&data->req);
 	if (err == -EINPROGRESS || err == -EBUSY) {
-		err = wait_for_completion_interruptible(
-			&data->result.completion);
-		if (!err)
-			err = data->result.err;
+		wait_for_completion(&data->result.completion);
+		err = data->result.err;
 	}
 
 	if (err)