linux-kernel - [PATCH] crypto-virtio: fix memory-leak

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Message-Id: <20220816075916.23651-1-helei.sig11@bytedance.com>
Date:   Tue, 16 Aug 2022 15:59:16 +0800
From:   Lei He <helei.sig11@...edance.com>
To:     arei.gonglei@...wei.com, herbert@...dor.apana.org.au
Cc:     mst@...hat.com, virtualization@...ts.linux-foundation.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        pizhenwei@...edance.com, lei he <helei.sig11@...edance.com>
Subject: [PATCH] crypto-virtio: fix memory-leak

From: lei he <helei.sig11@...edance.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@...ays.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@...edance.com>

# Please enter the commit message for your changes. Lines starting
# with '#' will be kept; you may remove them yourself if you want to.
# An empty message aborts the commit.
#
# Date:      Tue Aug 16 11:53:30 2022 +0800
#
# On branch master
# Your branch is ahead of 'origin/master' by 1 commit.
#   (use "git push" to publish your local commits)
#
# Changes to be committed:
#	modified:   drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
#
# Untracked files:
#	cert.der
#	key.der
#	key.pem
#

# Please enter the commit message for your changes. Lines starting
# with '#' will be kept; you may remove them yourself if you want to.
# An empty message aborts the commit.
#
# Date:      Tue Aug 16 11:53:30 2022 +0800
#
# On branch master
# Your branch is ahead of 'origin/master' by 1 commit.
#   (use "git push" to publish your local commits)
#
# Changes to be committed:
#	modified:   drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
#
# Untracked files:
#	cert.der
#	key.der
#	key.pem
#

# Please enter the commit message for your changes. Lines starting
# with '#' will be kept; you may remove them yourself if you want to.
# An empty message aborts the commit.
#
# Date:      Tue Aug 16 11:53:30 2022 +0800
#
# On branch master
# Your branch is ahead of 'origin/master' by 1 commit.
#   (use "git push" to publish your local commits)
#
# Changes to be committed:
#	modified:   drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
#
# Untracked files:
#	cert.der
#	key.der
#	key.pem
#
---
 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);
-- 
2.20.1