security

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 Go to latest Published: Apr 28, 2024 License: BSD-2-Clause-Patent Imports: 27 Imported by: 16

README

Control Plane Security Package

The control plane security package provides a centralized source for Control Plane functionality related to access control and identity. This functionality is used throughout the control plane, in the DAOS Agent, DAOS Control Server, and administrative tools.

This package implements the following:

  • Load and validate DAOS certificates.
  • Generate user credentials for client processes.
  • Sign and validate a data token with a certificate.
  • Configure gRPC communications to use mutually-authenticated TLS with certificates.
  • Define access for gRPC commands by DAOS component certificate type.

Credential Establishment

To assure the identity of a client process, the DAOS Agent generates a token to assert the user's identity to the server, and signs this token using the agent certificate. Credentials are established at the time of pool connect, and are associated with the pool handle for its lifetime.

Currently, the only authentication method available in DAOS is AUTH_SYS. The DAOS Agent gathers information about the effective UNIX user over the UNIX Domain Socket connection used to communicate from the client library to the DAOS Agent.

The workflow is as follows:

  1. A job application utilizing the DAOS client library requests to connect to a pool.
  2. The job application connects to the DAOS Agent requesting a security credential (token representing identity information).
  3. The DAOS Agent inspects the properties of the process (UID, GID, ACL, SELinux context) and uses that information to build and sign a credential.
  4. The DAOS Agent then passes this credential back to the DAOS client library, where it is used in the pool connect request, passing the security credential as an argument to the pool connect RPC.
  5. The DAOS I/O Engine receives the pool connect RPC and passes the security credential to the Control Plane component of the DAOS Server to validate the authenticity of the credential. If the credential is not valid, the request will be denied.
  6. If the security credential is deemed valid, the I/O Engine will compare the identity against the ACL for the pool, as described in the Access Control Enforcement section. If the identity has access, a pool handle is returned. Otherwise the error DER_NO_PERM is returned.

The framework used to establish the credentials can be further expanded to handle additional properties and authentication methods.

Certificate Usage in DAOS

Certificates are used in several locations to provide authentication and validation of user identity in a DAOS system. For information on how to set up the certificates in a DAOS system, see the Admin Guide.

Certificate Generation

When generating certificates for a DAOS system, four types of certificates are generated.

The first to be generated is the CA root certificate specific to this DAOS deployment. While it is advised to have per-system CA roots, there is no mechanism preventing reuse between DAOS deployments. The CA root is used to produce and validate the three remaining certificate types.

The three remaining certificate types that are generated are the admin, agent, and server certificates. The admin certificate is used to protect the gRPC channel between the administrative node and also provide validation of the administrative user. The Agent certificate is used to ensure that the compute node belongs to the DAOS system and also provides validation of process identity credentials. The server certificate is used in three separate ways. First, it is used to protect the gRPC channel between the administrative node and the server, second, it protects the channel between DAOS servers, and finally, it provides signing functionality for data transfers between the server and compute nodes.

DAOS provides a script and openssl configuration files for generating the various certificates needed by a DAOS installation. The script will craft a CA root certificate using the various configuration files found in the DAOS source tree. The config files contain the signing policies for the various other types of certificates as well, ensuring the cryptography used is as directed by current best practices for protecting TLS channels.

For the remaining certificates, DAOS uses the common name to ensure that the correct certificates are used for the correct components. Initially, there will only be one class of administrative user, and the Common Name for the gRPC TLS channel will be admin, ensuring only admin certificates may be used to issue administrative commands to the control plane. This is to ensure that if a key and cert are obtained from a compute node that it cannot be used to connect to the administrative interface. Likewise, we ensure that the appropriate certs are used by the Agent and the Server by encoding their names into the Common Name.

Protecting Administrative Channels with Certificates

Administration of a DAOS cluster will be performed by an administrator using the dmg utility and interfacing with the control plane service for the cluster. The control plane service is a distributed service provided by the DAOS cluster and resides on each node acting as a storage node. Even though the control plane service is present on every node, a subset of them is designated as the management nodes, and if you attempt to connect to a non-management node, it will attempt to redirect you to the entry point node for the cluster. The connections between dmg and the control plane processes are performed using gRPC. gRPC is an http2 based microservice architecture. The data structure and service definitions for gRPC are written in protobuf and then translated into the various languages used by DAOS (golang and C).

gRPC provides support for TLS authentication of the channel between the gRPC client and server. It provides the ability to authenticate both ends of the channel using both server and client-side validation. gRPC provides a mechanism to interpose additional checks on the TLS handshake to ensure certain properties of the connection are guaranteed. We use a server-side gRPC interceptor to ensure that the certificate that was used to negotiate the channel contains the appropriate Common Name.

Host Authentication with Certificates

Every compute node in the cluster is assigned a certificate for its agent. The agent certificate is used to verify the host's authenticity and the validity of the data it is signing. As part of the credential establishment process, an identity token is bound with a verifier consisting of a signed hash of the identity token along with the CommonName of the host signing the token. The agent will use the CommonName in the certificate in the token verifier. When the server receives the verifier, it will check for a certificate named with the CommonName for validation.

Part of the setup of the DAOS cluster is that all nodes acting as a server must have the certificate of all Agents that will be present in the cluster. In the case of a single certificate shared by all agents in the cluster, which is expected to be the most common case, this means that all servers will have a single Agent certificate file. The requirement that agents must be known to servers ahead of time makes it so an agent cannot be placed into the cluster without a properly issued certificate.

Credential Validation with Certificates

As mentioned in the previous sections, the Agents are responsible for generating identity tokens and signing them. This action is performed when a client application requests to connect to a pool. The Agent inspects the requesting process and generates a hashed verifier token and signs it with the private key file associated with the Agent's certificate. This token is packaged as part of the pool connect operation and is sent to the data plane using an RPC over the RDMA fabric channel. The data plane server sends a request to the control plane server to validate the identity token that has been provided. The control plane server inspects the verifier, extracts the name of the providing host, and checks for a certificate with that name. The server then validates the signature of the token using the certificate file associated with that host. If the identity token validates, then it is returned to the data plane server to make an access control check against the identity token.

Documentation

Index

Constants

View Source 
const (
	MaxUserOnlyKeyPerm os.FileMode = 0400
	MaxGroupKeyPerm    os.FileMode = 0440
	MaxCertPerm        os.FileMode = 0664
	MaxDirPerm         os.FileMode = 0750
)
View Source 
const ServerCommonName = "server"

Variables

View Source 
var (
	FaultUnknown = securityFault(
		code.SecurityUnknown,
		"unknown security error",
		"",
	)
)

Functions

func DialOptionForTransportConfig 

func DialOptionForTransportConfig(cfg *TransportConfig) (grpc.DialOption, error)

func FaultInvalidCert 

func FaultInvalidCert(err error) *fault.Fault

FaultInvalidCert indicates that a certificate was invalid.

func FaultInvalidCertFile 

func FaultInvalidCertFile(filePath string, err error) *fault.Fault

FaultInvalidCertFile indicates that a certificate loaded from a file was invalid.

func FaultMissingCertFile 

func FaultMissingCertFile(filePath string) *fault.Fault

func FaultUnreadableCertFile 

func FaultUnreadableCertFile(filePath string) *fault.Fault

func GetClientTransportCredentials 

func GetClientTransportCredentials(cfg *TransportConfig) (credentials.TransportCredentials, error)

func GetServerTransportCredentials 

func GetServerTransportCredentials(cfg *TransportConfig) (credentials.TransportCredentials, error)

func LoadCertificate 

func LoadCertificate(certPath string) (*x509.Certificate, error)

LoadCertificate loads the certificate specified at the given path into an x509 Certificate object

func LoadPEMData 

func LoadPEMData(filePath string, perms os.FileMode) ([]byte, error)

LoadPEMData handles security checking on the PEM file based on perms and returns the bytes in the PEM file

func LoadPrivateKey 

func LoadPrivateKey(keyPath string) (crypto.PrivateKey, error)

LoadPrivateKey loads the private key specified at the given path into an crypto.PrivateKey interface compliant object.

func MethodToComponent 

func MethodToComponent(method string) (build.Component, error)

MethodToComponent resolves a gRPC method string to a build.Component.

func ServerOptionForTransportConfig 

func ServerOptionForTransportConfig(cfg *TransportConfig) (grpc.ServerOption, error)

func ValidateCertDirectory 

func ValidateCertDirectory(certDir string) error

ValidateCertDirectory ensures the certificate directory has safe permissions set on it.

Types

type CertificateConfig 

type CertificateConfig struct {
	ServerName      string `yaml:"-"`
	ClientCertDir   string `yaml:"client_cert_dir,omitempty"`
	CARootPath      string `yaml:"ca_cert"`
	CertificatePath string `yaml:"cert"`
	PrivateKeyPath  string `yaml:"key"`
	// contains filtered or unexported fields
}

CertificateConfig contains the specific certificate information for the daos component. ServerName is only needed if the config is being used as a transport credential for a gRPC tls client.

type Component 

type Component int

Component represents the DAOS component being granted authorization. 

const (
	ComponentUndefined Component = iota
	ComponentAdmin
	ComponentAgent
	ComponentServer
)

func CommonNameToComponent 

func CommonNameToComponent(commonname string) Component

CommonNameToComponent returns the correct component based on the CommonName

func (Component) HasAccess 

func (c Component) HasAccess(FullMethod string) bool

HasAccess check if the given component has access to method given in FullMethod

func (Component) String 

func (c Component) String() string

type DomainInfo 

type DomainInfo struct {
	// contains filtered or unexported fields
}

DomainInfo holds our socket credentials to be used by the DomainSocketServer

func DomainInfoFromUnixConn 

func DomainInfoFromUnixConn(log logging.Logger, sock *net.UnixConn) (*DomainInfo, error)

DomainInfoFromUnixConn determines credentials from a unix socket.

func InitDomainInfo 

func InitDomainInfo(creds *syscall.Ucred, ctx string) *DomainInfo

InitDomainInfo returns an initialized DomainInfo structure

func (*DomainInfo) Ctx 

func (d *DomainInfo) Ctx() string

Ctx returns the additional security information obtained from the domain socket

func (*DomainInfo) Gid 

func (d *DomainInfo) Gid() uint32

Gid returns the GID obtained from the domain socket

func (*DomainInfo) String 

func (d *DomainInfo) String() string

func (*DomainInfo) Uid 

func (d *DomainInfo) Uid() uint32

Uid returns the UID obtained from the domain socket

type TokenSigner 

type TokenSigner struct {
	// contains filtered or unexported fields
}

TokenSigner serves to encapsulate the functionality needed to sign and verify auth token signatures.

func DefaultTokenSigner 

func DefaultTokenSigner() *TokenSigner

DefaultTokenSigner creates a TokenSigner with an instantiated entropy pool.

func (*TokenSigner) Hash 

func (s *TokenSigner) Hash(data []byte) ([]byte, error)

Hash returns the SHA-512 hash of the byte array passed in.

func (*TokenSigner) Sign 

func (s *TokenSigner) Sign(key crypto.PrivateKey, data []byte) ([]byte, error)

Sign takes an unhashed set of bytes and hashes and signs the result with the key passed in.

func (*TokenSigner) Verify 

func (s *TokenSigner) Verify(key crypto.PublicKey, data []byte, sig []byte) error

Verify takes an unhashed set of bytes and hashes the data and verifies the signature against the hash and the publickey passed in.

type TransportConfig 

type TransportConfig struct {
	AllowInsecure     bool `yaml:"allow_insecure"`
	CertificateConfig `yaml:",inline"`
}

TransportConfig contains all the information on whether or not to use certificates and their location if their use is specified.

func DefaultAgentTransportConfig 

func DefaultAgentTransportConfig() *TransportConfig

DefaultAgentTransportConfig provides a default transport config disabling certificate usage and specifying certificates located under /etc/daos/certs.

func DefaultClientTransportConfig 

func DefaultClientTransportConfig() *TransportConfig

DefaultClientTransportConfig provides a default transport config disabling certificate usage and specifying certificates located under /etc/daos/certs. As this credential is meant to be used as a client credential it specifies a default ServerName as well.

func DefaultServerTransportConfig 

func DefaultServerTransportConfig() *TransportConfig

DefaultServerTransportConfig provides a default transport config disabling certificate usage and specifying certificates located under /etc/daos.

func (*TransportConfig) PreLoadCertData 

func (tc *TransportConfig) PreLoadCertData() error

PreLoadCertData reads the certificate files in and parses them into TLS key pair and Certificate pool to provide a mechanism for detecting certificate error before first use.

func (*TransportConfig) PrivateKey 

func (tc *TransportConfig) PrivateKey() (crypto.PrivateKey, error)

PrivateKey returns the private key stored in the certificates loaded into the TransportConfig

func (*TransportConfig) PublicKey 

func (tc *TransportConfig) PublicKey() (crypto.PublicKey, error)

PublicKey returns the private key stored in the certificates loaded into the TransportConfig

func (*TransportConfig) ReloadCertData 

func (tc *TransportConfig) ReloadCertData() error

ReloadCertData reloads and stores the certificate data in the case when certificate data has changed since initial loading.

func (*TransportConfig) String 

func (tc *TransportConfig) String() string

type UnsupportedKeyError 

type UnsupportedKeyError struct{}

UnsupportedKeyError is a structured error used to indicate that the PublicKey or PrivateKey interface passed in represents a key type we do not support.

func (*UnsupportedKeyError) Error 

func (err *UnsupportedKeyError) Error() string

Error is the implementation of the error interface.

Source Files

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