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From:   Ard Biesheuvel <ard.biesheuvel@linaro.org>
To:     linux-crypto@vger.kernel.org
Cc:     Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Biggers <ebiggers@google.com>,
        linux-arm-kernel@lists.infradead.org,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Gonglei <arei.gonglei@huawei.com>,
        virtualization@lists.linux-foundation.org
Subject: [PATCH 02/25] crypto: virtio - deal with unsupported input sizes
Date:   Mon, 14 Oct 2019 14:18:47 +0200
Message-Id: <20191014121910.7264-3-ard.biesheuvel@linaro.org>
In-Reply-To: <20191014121910.7264-1-ard.biesheuvel@linaro.org>
References: <20191014121910.7264-1-ard.biesheuvel@linaro.org>
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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 <ard.biesheuvel@linaro.org>
---
 drivers/crypto/virtio/virtio_crypto_algs.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
index 65ec10800137..82b316b2f537 100644
--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -105,8 +105,6 @@ virtio_crypto_alg_validate_key(int key_len, uint32_t *alg)
 		*alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
 		break;
 	default:
-		pr_err("virtio_crypto: Unsupported key length: %d\n",
-			key_len);
 		return -EINVAL;
 	}
 	return 0;
@@ -489,6 +487,11 @@ static int virtio_crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
 	/* 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->dataq = data_vq;
 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
 	vc_sym_req->ablkcipher_ctx = ctx;
@@ -509,6 +512,11 @@ static int virtio_crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
 	/* 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->dataq = data_vq;
 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
 	vc_sym_req->ablkcipher_ctx = ctx;
-- 
2.20.1