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 lengths 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.

CVE-2020-10724
Fixes: e80a98708166 ("vhost/crypto: add session message handler")
Cc: stable@dpdk.org
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>

diff --git a/lib/librte_vhost/vhost_crypto.c b/lib/librte_vhost/vhost_crypto.c
index 2e52ecae87dcc57e5bea6c130159efb5967b8e59..0f9df4059d0b1e84f65c47b615aa64b493bbfd75 100644 (file)
--- a/lib/librte_vhost/vhost_crypto.c
+++ b/lib/librte_vhost/vhost_crypto.c
@@ -238,6 +238,11 @@ 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)
@@ -288,6 +293,12 @@ 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;
@@ -302,6 +313,12 @@ 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;