crypto: virtio: Fix use-after-free in virtio_crypto_skcipher_finalize_req()
authorLongpeng(Mike) <longpeng2@huawei.com>
Tue, 2 Jun 2020 07:05:00 +0000 (15:05 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Jun 2020 14:40:31 +0000 (16:40 +0200)
commit2ef260d686b50823faad77583e068c7305c3fe5f
treeea7b5680b22fb5c0ca31d762d6b903df4f018e38
parent0070e73c9edc8630a87bea8c04ba217bbe312792
crypto: virtio: Fix use-after-free in virtio_crypto_skcipher_finalize_req()

[ Upstream commit 8c855f0720ff006d75d0a2512c7f6c4f60ff60ee ]

The system'll crash when the users insmod crypto/tcrypto.ko with mode=155
( testing "authenc(hmac(sha1),cbc(aes))" ). It's caused by reuse the memory
of request structure.

In crypto_authenc_init_tfm(), the reqsize is set to:
  [PART 1] sizeof(authenc_request_ctx) +
  [PART 2] ictx->reqoff +
  [PART 3] MAX(ahash part, skcipher part)
and the 'PART 3' is used by both ahash and skcipher in turn.

When the virtio_crypto driver finish skcipher req, it'll call ->complete
callback(in crypto_finalize_skcipher_request) and then free its
resources whose pointers are recorded in 'skcipher parts'.

However, the ->complete is 'crypto_authenc_encrypt_done' in this case,
it will use the 'ahash part' of the request and change its content,
so virtio_crypto driver will get the wrong pointer after ->complete
finish and mistakenly free some other's memory. So the system will crash
when these memory will be used again.

The resources which need to be cleaned up are not used any more. But the
pointers of these resources may be changed in the function
"crypto_finalize_skcipher_request". Thus release specific resources before
calling this function.

Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver")
Reported-by: LABBE Corentin <clabbe@baylibre.com>
Cc: Gonglei <arei.gonglei@huawei.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: virtualization@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200123101000.GB24255@Red
Acked-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Link: https://lore.kernel.org/r/20200602070501.2023-3-longpeng2@huawei.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/crypto/virtio/virtio_crypto_algs.c