lkml.org 
[lkml]   [2020]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/2] crypto: virtio: fix an memory use-after-free bug
Date
The system'll crash when we insmod crypto/tcrypto.ko with mode=155.

After dig into this case, I find it's caused by reuse the request
memory.

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

When virtio_crypto driver finish skcipher req, it'll call ->complete
callback(in crypto_finalize_skcipher_request) and then free its
resources which 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 memory. So the system will crash
at last when this memory be used again.

We can free the resources before calling ->complete to fix this issue.

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

Reported-by: LABBE Corentin <clabbe@baylibre.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
drivers/crypto/virtio/virtio_crypto_algs.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
index 2fa1129f96d6..3800356fb764 100644
--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -587,10 +587,11 @@ static void virtio_crypto_skcipher_finalize_req(
scatterwalk_map_and_copy(req->iv, req->dst,
req->cryptlen - AES_BLOCK_SIZE,
AES_BLOCK_SIZE, 0);
- crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
- req, err);
kzfree(vc_sym_req->iv);
virtcrypto_clear_request(&vc_sym_req->base);
+
+ crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
+ req, err);
}

static struct virtio_crypto_algo virtio_crypto_algs[] = { {
--
2.17.1
\
 
 \ /
  Last update: 2020-05-25 02:57    [W:0.056 / U:24.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site