[PATCH 3/4] crypto: gcm wait for crypto op not signal safe

[Gilad Ben-Yossef]

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@xxxxxxxxx>
Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
---
 crypto/drbg.c | 4 ++--
 crypto/gcm.c  | 6 ++----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index fa9054d..cdb27ac 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1767,8 +1767,8 @@ static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 			break;
 		case -EINPROGRESS:
 		case -EBUSY:
-			ret = wait_for_completion(&drbg->ctr_completion);
-			if (!ret && !drbg->ctr_async_err) {
+			wait_for_completion(&drbg->ctr_completion);
+			if (!drbg->ctr_async_err) {
 				reinit_completion(&drbg->ctr_completion);
 				break;
 			}
diff --git a/crypto/gcm.c b/crypto/gcm.c
index b7ad808..3841b5e 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)
-- 
2.1.4