package ca import ( "crypto/x509" "errors" "github.com/hashicorp/go-hclog" ) //go:generate mockery -name Provider -inpkg // ErrRateLimited is a sentinel error value Providers may return from any method // to indicate that the operation can't complete due to a temporary rate limit. // In the case of signing new certificates, Consul clients will respect this and // intelligently backoff to optimize rotation rollout time while reducing load // on servers and CA provider. var ErrRateLimited = errors.New("operation rate limited by CA provider") // PrimaryIntermediateProviders is a list of CA providers that make use use of an // intermediate cert in the primary datacenter as well as the secondary. This is used // when determining whether to run the intermediate renewal routine in the primary. var PrimaryIntermediateProviders = map[string]struct{}{ "vault": {}, } // ProviderConfig encapsulates all the data Consul passes to `Configure` on a // new provider instance. The provider must treat this as read-only and make // copies of any map or slice if it might modify them internally. type ProviderConfig struct { // ClusterID is the current Consul cluster ID. ClusterID string // Datacenter is the current Consul datacenter. Datacenter string // IsPrimary is true when the CA instance is in the primary DC typically it // may choose to act as a root in this case while secondaries are typically // intermediate CAs. In some case the primary DC in Consul is an intermediate // signed by some external CA along with that CA's public cert so the old name // of `IsRoot` was misleading. IsPrimary bool // RawConfig is the user configuration for the provider and is // provider-specific to be interpreted as the provider wishes. RawConfig map[string]interface{} // State contains the State the same provider last persisted. It is provided // after a restart or reconfiguration, or on a leader election on a new server // to maintain operation. It MUST NOT be used for secret storage since it is // visible in the API to operators. It's intended use is to store small bits // of state like UUIDs of external resources that the provider has created and // needs to continue to manage. State map[string]string } // Provider is the interface for Consul to interact with // an external CA that provides leaf certificate signing for // given SpiffeIDServices. type Provider interface { // Configure initializes the provider based on the given cluster ID, root // status and configuration values. rawConfig contains the user-provided // Config. State contains a the State the same provider last persisted on a // restart or reconfiguration. The provider must not modify `rawConfig` or // `state` maps directly as it may be being read from other goroutines. Configure(cfg ProviderConfig) error // State returns the current provider state. If the provider doesn't need to // store anything other than what the user configured this can return nil. It // is called after any config change before the new active config is stored in // the state store and the most recent value returned by the provider is given // in subsequent `Configure` calls provided that the current provider is the // same type as the new provider instance being configured. This provides a // simple way for providers to persist information like UUIDs of resources // they manage. This state is visible to anyone with operator:read via the API // so it's not intended for storing secrets like root private keys. Only // strings are permitted since this has to pass through msgpack and so // interface values will end up mangled in many cases which is ugly for all // provider code to have to remember to reason about. // // Note that the map returned will be accessed (read-only) in other goroutines // - for example passed to Configure in the Connect CA Config RPC endpoint - // so it must not just be a pointer to a map that may internally be modified. // If the Provider only writes to it during Configure it's safe to return // as-is, but otherwise it's assumed the map returned is a copy of the state // in the Provider struct so it won't change after being returned. State() (map[string]string, error) // GenerateRoot causes the creation of a new root certificate for this provider. // This can also be a no-op if a root certificate already exists for the given // config. If IsPrimary is false, calling this method is an error. GenerateRoot() error // ActiveRoot returns the currently active root CA for this // provider. This should be a parent of the certificate returned by // ActiveIntermediate() ActiveRoot() (string, error) // GenerateIntermediateCSR generates a CSR for an intermediate CA // certificate, to be signed by the root of another datacenter. If IsPrimary was // set to true with Configure(), calling this is an error. GenerateIntermediateCSR() (string, error) // SetIntermediate sets the provider to use the given intermediate certificate // as well as the root it was signed by. This completes the initialization for // a provider where IsPrimary was set to false in Configure(). SetIntermediate(intermediatePEM, rootPEM string) error // ActiveIntermediate returns the current signing cert used by this provider // for generating SPIFFE leaf certs. Note that this must not change except // when Consul requests the change via GenerateIntermediate. Changing the // signing cert will break Consul's assumptions about which validation paths // are active. ActiveIntermediate() (string, error) // GenerateIntermediate returns a new intermediate signing cert and sets it to // the active intermediate. If multiple intermediates are needed to complete // the chain from the signing certificate back to the active root, they should // all by bundled here. GenerateIntermediate() (string, error) // Sign signs a leaf certificate used by Connect proxies from a CSR. The PEM // returned should include only the leaf certificate as all Intermediates // needed to validate it will be added by Consul based on the active // intemediate and any cross-signed intermediates managed by Consul. Note that // providers should return ErrRateLimited if they are unable to complete the // operation due to upstream rate limiting so that clients can intelligently // backoff. Sign(*x509.CertificateRequest) (string, error) // SignIntermediate will validate the CSR to ensure the trust domain in the // URI SAN matches the local one and that basic constraints for a CA // certificate are met. It should return a signed CA certificate with a path // length constraint of 0 to ensure that the certificate cannot be used to // generate further CA certs. Note that providers should return ErrRateLimited // if they are unable to complete the operation due to upstream rate limiting // so that clients can intelligently backoff. SignIntermediate(*x509.CertificateRequest) (string, error) // CrossSignCA must accept a CA certificate from another CA provider and cross // sign it exactly as it is such that it forms a chain back the the // CAProvider's current root. Specifically, the Distinguished Name, Subject // Alternative Name, SubjectKeyID and other relevant extensions must be kept. // The resulting certificate must have a distinct Serial Number and the // AuthorityKeyID set to the CAProvider's current signing key as well as the // Issuer related fields changed as necessary. The resulting certificate is // returned as a PEM formatted string. // // If the CA provider does not support this operation, it may return an error // provided `SupportsCrossSigning` also returns false. Note that // providers should return ErrRateLimited if they are unable to complete the // operation due to upstream rate limiting so that clients can intelligently // backoff. CrossSignCA(*x509.Certificate) (string, error) // SupportsCrossSigning should indicate whether the CA provider supports // cross-signing an external root to provide a seamless rotation. If the CA // does not support this, the user will have to force an upgrade when that CA // provider is the current CA as the upgrade may cause interruptions to // connectivity during the rollout. SupportsCrossSigning() (bool, error) // Cleanup performs any necessary cleanup that should happen when the provider // is shut down permanently, such as removing a temporary PKI backend in Vault // created for an intermediate CA. Cleanup() error } // NeedsLogger is an optional interface that allows a CA provider to use the // Consul logger to output diagnostic messages. type NeedsLogger interface { // SetLogger will pass a configured Logger to the provider. SetLogger(logger hclog.Logger) } // NeedsStop is an optional interface that allows a CA to define a function // to be called when the CA instance is no longer in use. This is different // from Cleanup(), as only the local provider instance is being shut down // such as in the case of a leader change. type NeedsStop interface { Stop() }