From 963b6eea05f3ee720fcfecd110e20f61b92205d6 Mon Sep 17 00:00:00 2001
From: Maxime Coquelin <maxime.coquelin@redhat.com>
Date: Tue, 21 Apr 2020 19:10:09 +0200
Subject: vhost/crypto: validate keys lengths

transform_cipher_param() and transform_chain_param() handle
the payload data for the VHOST_USER_CRYPTO_CREATE_SESS
message. These payloads have to be validated, since it
could come from untrusted sources.

Two buffers and their lenghts are defined in this payload,
one the the auth key and one for the cipher key. But above
functions do not validate the key length inputs, which could
lead to read out of bounds, as buffers have static sizes of
64 bytes for the cipher key and 512 bytes for the auth key.

This patch adds necessary checks on the key length field
before being used.

Fixes: e80a98708166 ("vhost/crypto: add session message handler")

This issue has been assigned CVE-2020-10724

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Xiaolong Ye <xiaolong.ye@intel.com>
Reviewed-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
---
 lib/librte_vhost/vhost_crypto.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/lib/librte_vhost/vhost_crypto.c b/lib/librte_vhost/vhost_crypto.c
index 6891197..07a4115 100644
--- a/lib/librte_vhost/vhost_crypto.c
+++ b/lib/librte_vhost/vhost_crypto.c
@@ -237,6 +237,11 @@ transform_cipher_param(struct rte_crypto_sym_xform *xform,
 	if (unlikely(ret < 0))
 		return ret;
 
+	if (param->cipher_key_len > VHOST_USER_CRYPTO_MAX_CIPHER_KEY_LENGTH) {
+		VC_LOG_DBG("Invalid cipher key length\n");
+		return -VIRTIO_CRYPTO_BADMSG;
+	}
+
 	xform->type = RTE_CRYPTO_SYM_XFORM_CIPHER;
 	xform->cipher.key.length = param->cipher_key_len;
 	if (xform->cipher.key.length > 0)
@@ -287,6 +292,12 @@ transform_chain_param(struct rte_crypto_sym_xform *xforms,
 			&xform_cipher->cipher.algo);
 	if (unlikely(ret < 0))
 		return ret;
+
+	if (param->cipher_key_len > VHOST_USER_CRYPTO_MAX_CIPHER_KEY_LENGTH) {
+		VC_LOG_DBG("Invalid cipher key length\n");
+		return -VIRTIO_CRYPTO_BADMSG;
+	}
+
 	xform_cipher->type = RTE_CRYPTO_SYM_XFORM_CIPHER;
 	xform_cipher->cipher.key.length = param->cipher_key_len;
 	xform_cipher->cipher.key.data = param->cipher_key_buf;
@@ -301,6 +312,12 @@ transform_chain_param(struct rte_crypto_sym_xform *xforms,
 	ret = auth_algo_transform(param->hash_algo, &xform_auth->auth.algo);
 	if (unlikely(ret < 0))
 		return ret;
+
+	if (param->auth_key_len > VHOST_USER_CRYPTO_MAX_HMAC_KEY_LENGTH) {
+		VC_LOG_DBG("Invalid auth key length\n");
+		return -VIRTIO_CRYPTO_BADMSG;
+	}
+
 	xform_auth->auth.digest_length = param->digest_len;
 	xform_auth->auth.key.length = param->auth_key_len;
 	xform_auth->auth.key.data = param->auth_key_buf;
-- 
cgit v1.0

