From 19c5da7d4a2662e85ea67d2d81df57e038fde3ab Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Sat, 9 Nov 2019 18:09:27 +0100
Subject: [PATCH] crypto: virtio - deal with unsupported input sizes
Git-commit: 19c5da7d4a2662e85ea67d2d81df57e038fde3ab
Patch-mainline: v5.5-rc1
References: git-fixes

Return -EINVAL for input sizes that are not a multiple of the AES
block size, since they are not supported by our CBC chaining mode.

While at it, remove the pr_err() that reports unsupported key sizes
being used: we shouldn't spam the kernel log with that.

Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver")
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Gonglei <arei.gonglei@huawei.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Torsten Duwe <duwe@suse.de>

---
 drivers/crypto/virtio/virtio_crypto_algs.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -60,8 +60,6 @@ virtio_crypto_alg_validate_key(int key_l
 		*alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
 		break;
 	default:
-		pr_err("virtio_crypto: Unsupported key length: %d\n",
-			key_len);
 		return -EINVAL;
 	}
 	return 0;
@@ -438,6 +436,11 @@ static int virtio_crypto_ablkcipher_encr
 	/* Use the first data virtqueue as default */
 	struct data_queue *data_vq = &vcrypto->data_vq[0];
 
+	if (!req->nbytes)
+		return 0;
+	if (req->nbytes % AES_BLOCK_SIZE)
+		return -EINVAL;
+
 	vc_req->ablkcipher_ctx = ctx;
 	vc_req->ablkcipher_req = req;
 	vc_req->encrypt = true;
@@ -455,6 +458,11 @@ static int virtio_crypto_ablkcipher_decr
 	/* Use the first data virtqueue as default */
 	struct data_queue *data_vq = &vcrypto->data_vq[0];
 
+	if (!req->nbytes)
+		return 0;
+	if (req->nbytes % AES_BLOCK_SIZE)
+		return -EINVAL;
+
 	vc_req->ablkcipher_ctx = ctx;
 	vc_req->ablkcipher_req = req;