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From:   Lei He <helei.sig11@bytedance.com>
To:     mst@redhat.com, herbert@gondor.apana.org.au,
        arei.gonglei@huawei.com
Cc:     virtualization@lists.linux-foundation.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        pizhenwei@bytedance.com, lei he <helei.sig11@bytedance.com>
Subject: [PATCH v2] virtio-crypto: fix memory-leak
Date:   Tue, 16 Aug 2022 17:43:36 +0800
Message-Id: <20220816094336.27806-1-helei.sig11@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: lei he <helei.sig11@bytedance.com>

Fix memory-leak for virtio-crypto akcipher request, this problem is
introduced by 59ca6c93387d3(virtio-crypto: implement RSA algorithm).
The leak can be reproduced and tested with the following script
inside virtual machine:

#!/bin/bash

LOOP_TIMES=10000

# required module: pkcs8_key_parser, virtio_crypto
modprobe pkcs8_key_parser # if CONFIG_PKCS8_PRIVATE_KEY_PARSER=m
modprobe virtio_crypto # if CONFIG_CRYPTO_DEV_VIRTIO=m
rm -rf /tmp/data
dd if=/dev/random of=/tmp/data count=1 bs=230

# generate private key and self-signed cert
openssl req -nodes -x509 -newkey rsa:2048 -keyout key.pem \
		-outform der -out cert.der  \
		-subj "/C=CN/ST=GD/L=SZ/O=vihoo/OU=dev/CN=always.com/emailAddress=yy@always.com"
# convert private key from pem to der
openssl pkcs8 -in key.pem -topk8 -nocrypt -outform DER -out key.der

# add key
PRIV_KEY_ID=`cat key.der | keyctl padd asymmetric test_priv_key @s`
echo "priv key id = "$PRIV_KEY_ID
PUB_KEY_ID=`cat cert.der | keyctl padd asymmetric test_pub_key @s`
echo "pub key id = "$PUB_KEY_ID

# query key
keyctl pkey_query $PRIV_KEY_ID 0
keyctl pkey_query $PUB_KEY_ID 0

# here we only run pkey_encrypt becasuse it is the fastest interface
function bench_pub() {
	keyctl pkey_encrypt $PUB_KEY_ID 0 /tmp/data enc=pkcs1 >/tmp/enc.pub
}

# do bench_pub in loop to obtain the memory leak
for (( i = 0; i < ${LOOP_TIMES}; ++i )); do
	bench_pub
done

Signed-off-by: lei he <helei.sig11@bytedance.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
---
 drivers/crypto/virtio/virtio_crypto_akcipher_algs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
index 2a60d0525cde..168195672e2e 100644
--- a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
@@ -56,6 +56,10 @@ static void virtio_crypto_akcipher_finalize_req(
 	struct virtio_crypto_akcipher_request *vc_akcipher_req,
 	struct akcipher_request *req, int err)
 {
+	kfree(vc_akcipher_req->src_buf);
+	kfree(vc_akcipher_req->dst_buf);
+	vc_akcipher_req->src_buf = NULL;
+	vc_akcipher_req->dst_buf = NULL;
 	virtcrypto_clear_request(&vc_akcipher_req->base);
 
 	crypto_finalize_akcipher_request(vc_akcipher_req->base.dataq->engine, req, err);

base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
-- 
2.20.1