crypto: gcm - wait for crypto op not signal safe

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>
CC: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 4 deletions

diff --git a/crypto/gcm.c b/crypto/gcm.c
index b7ad808be3d4..3841b5eafa7e 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -152,10 +152,8 @@ static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
 
         err = crypto_skcipher_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)