diff --git a/authority/authority.go b/authority/authority.go index fe00eff2..95e58294 100644 --- a/authority/authority.go +++ b/authority/authority.go @@ -1,6 +1,7 @@ package authority import ( + "bytes" "context" "crypto" "crypto/sha256" @@ -24,6 +25,7 @@ import ( adminDBNosql "github.com/smallstep/certificates/authority/admin/db/nosql" "github.com/smallstep/certificates/authority/administrator" "github.com/smallstep/certificates/authority/config" + "github.com/smallstep/certificates/authority/internal/constraints" "github.com/smallstep/certificates/authority/policy" "github.com/smallstep/certificates/authority/provisioner" "github.com/smallstep/certificates/cas" @@ -46,14 +48,15 @@ type Authority struct { linkedCAToken string // X509 CA - password []byte - issuerPassword []byte - x509CAService cas.CertificateAuthorityService - rootX509Certs []*x509.Certificate - rootX509CertPool *x509.CertPool - federatedX509Certs []*x509.Certificate - certificates *sync.Map - x509Enforcers []provisioner.CertificateEnforcer + password []byte + issuerPassword []byte + x509CAService cas.CertificateAuthorityService + rootX509Certs []*x509.Certificate + rootX509CertPool *x509.CertPool + federatedX509Certs []*x509.Certificate + intermediateX509Certs []*x509.Certificate + certificates *sync.Map + x509Enforcers []provisioner.CertificateEnforcer // SCEP CA scepService *scep.Service @@ -80,10 +83,9 @@ type Authority struct { authorizeRenewFunc provisioner.AuthorizeRenewFunc authorizeSSHRenewFunc provisioner.AuthorizeSSHRenewFunc - // Constraint engine - - // Policy engines - policyEngine *policy.Engine + // Constraints and Policy engines + constraintsEngine *constraints.Engine + policyEngine *policy.Engine adminMutex sync.RWMutex @@ -375,6 +377,11 @@ func (a *Authority) init() error { if err != nil { return err } + // If not defined with an option, add intermediates to the the list + // of used for constraints purposes. + if len(a.intermediateX509Certs) == 0 { + a.intermediateX509Certs = append(a.intermediateX509Certs, options.CertificateChain...) + } } a.x509CAService, err = cas.New(ctx, options) if err != nil { @@ -612,6 +619,21 @@ func (a *Authority) init() error { return err } + // Load X509 constraints engine. + // + // This is currently only available in CA mode. + if size := len(a.intermediateX509Certs); size > 0 { + last := a.intermediateX509Certs[size-1] + constraintCerts := make([]*x509.Certificate, 0, size+1) + constraintCerts = append(constraintCerts, a.intermediateX509Certs...) + for _, root := range a.rootX509Certs { + if bytes.Equal(last.RawIssuer, root.RawSubject) && bytes.Equal(last.AuthorityKeyId, root.SubjectKeyId) { + constraintCerts = append(constraintCerts, root) + } + } + a.constraintsEngine = constraints.New(constraintCerts...) + } + // Load x509 and SSH Policy Engines if err := a.reloadPolicyEngines(ctx); err != nil { return err diff --git a/authority/options.go b/authority/options.go index 9cef89f0..cc2fc532 100644 --- a/authority/options.go +++ b/authority/options.go @@ -151,16 +151,23 @@ func WithKeyManager(k kms.KeyManager) Option { // WithX509Signer defines the signer used to sign X509 certificates. func WithX509Signer(crt *x509.Certificate, s crypto.Signer) Option { + return WithX509SignerChain([]*x509.Certificate{crt}, s) +} + +// WithX509SignerChain defines the signer used to sign X509 certificates. This +// option is similar to WithX509Signer but it supports a chain of intermediates. +func WithX509SignerChain(issuerChain []*x509.Certificate, s crypto.Signer) Option { return func(a *Authority) error { srv, err := cas.New(context.Background(), casapi.Options{ Type: casapi.SoftCAS, Signer: s, - CertificateChain: []*x509.Certificate{crt}, + CertificateChain: issuerChain, }) if err != nil { return err } a.x509CAService = srv + a.intermediateX509Certs = append(a.intermediateX509Certs, issuerChain...) return nil } } @@ -233,6 +240,25 @@ func WithX509FederatedCerts(certs ...*x509.Certificate) Option { } } +// WithX509RootCerts is an option that allows to define the list of intermediate +// certificates that the CA will be using. This option will replace any +// intermediate certificate defined before. +// +// Note that these certificates will not be bundled with the certificates signed +// by the CA, the CAS service will take care of that, although they should +// match, this is not guaranteed. These certificates will be mainly used for +// constraint purposes. +// +// This option should only used on specific configurations, for example when +// WithX509SignerFunc is used, as we don't know the list of intermediates on +// advance. +func WithX509IntermediateCerts(intermediateCerts ...*x509.Certificate) Option { + return func(a *Authority) error { + a.intermediateX509Certs = intermediateCerts + return nil + } +} + // WithX509RootBundle is an option that allows to define the list of root // certificates. This option will replace any root certificate defined before. func WithX509RootBundle(pemCerts []byte) Option { diff --git a/authority/tls.go b/authority/tls.go index 632ac238..dadf6d99 100644 --- a/authority/tls.go +++ b/authority/tls.go @@ -256,6 +256,9 @@ func (a *Authority) Sign(csr *x509.CertificateRequest, signOpts provisioner.Sign // isAllowedToSignX509Certificate checks if the Authority is allowed // to sign the X.509 certificate. func (a *Authority) isAllowedToSignX509Certificate(cert *x509.Certificate) error { + if err := a.constraintsEngine.ValidateCertificate(cert); err != nil { + return err + } return a.policyEngine.IsX509CertificateAllowed(cert) } @@ -351,6 +354,12 @@ func (a *Authority) Rekey(oldCert *x509.Certificate, pk crypto.PublicKey) ([]*x5 newCert.ExtraExtensions = append(newCert.ExtraExtensions, ext) } + // Check if the certificate is allowed to be renewed, policies or + // constraints might change over time. + if err := a.isAllowedToSignX509Certificate(newCert); err != nil { + return nil, err + } + resp, err := a.x509CAService.RenewCertificate(&casapi.RenewCertificateRequest{ Template: newCert, Lifetime: lifetime, diff --git a/authority/tls_test.go b/authority/tls_test.go index a8521b51..b3156a71 100644 --- a/authority/tls_test.go +++ b/authority/tls_test.go @@ -22,6 +22,7 @@ import ( "go.step.sm/crypto/jose" "go.step.sm/crypto/keyutil" + "go.step.sm/crypto/minica" "go.step.sm/crypto/pemutil" "go.step.sm/crypto/x509util" @@ -1589,3 +1590,86 @@ func TestAuthority_Revoke(t *testing.T) { }) } } + +func TestAuthority_constraints(t *testing.T) { + ca, err := minica.New( + minica.WithIntermediateTemplate(`{ + "subject": {{ toJson .Subject }}, + "keyUsage": ["certSign", "crlSign"], + "basicConstraints": { + "isCA": true, + "maxPathLen": 0 + }, + "nameConstraints": { + "critical": true, + "permittedDNSDomains": ["internal.example.org"], + "excludedDNSDomains": ["internal.example.com"], + "permittedIPRanges": ["192.168.1.0/24", "192.168.2.1/32"], + "excludedIPRanges": ["192.168.3.0/24", "192.168.4.0/28"], + "permittedEmailAddresses": ["root@example.org", "example.org", ".acme.org"], + "excludedEmailAddresses": ["root@example.com", "example.com", ".acme.com"], + "permittedURIDomains": ["uuid.example.org", ".acme.org"], + "excludedURIDomains": ["uuid.example.com", ".acme.com"] + } + }`), + ) + if err != nil { + t.Fatal(err) + } + + auth, err := NewEmbedded(WithX509RootCerts(ca.Root), WithX509Signer(ca.Intermediate, ca.Signer)) + if err != nil { + t.Fatal(err) + } + signer, err := keyutil.GenerateDefaultSigner() + if err != nil { + t.Fatal(err) + } + + tests := []struct { + name string + sans []string + wantErr bool + }{ + {"ok dns", []string{"internal.example.org", "host.internal.example.org"}, false}, + {"ok ip", []string{"192.168.1.10", "192.168.2.1"}, false}, + {"ok email", []string{"root@example.org", "info@example.org", "info@www.acme.org"}, false}, + {"ok uri", []string{"https://uuid.example.org/b908d973-5167-4a62-abe3-6beda358d82a", "https://uuid.acme.org/1724aae1-1bb3-44fb-83c3-9a1a18df67c8"}, false}, + {"fail permitted dns", []string{"internal.acme.org"}, true}, + {"fail excluded dns", []string{"internal.example.com"}, true}, + {"fail permitted ips", []string{"192.168.2.10"}, true}, + {"fail excluded ips", []string{"192.168.3.1"}, true}, + {"fail permitted emails", []string{"root@acme.org"}, true}, + {"fail excluded emails", []string{"root@example.com"}, true}, + {"fail permitted uris", []string{"https://acme.org/uuid/7848819c-9d0b-4e12-bbff-cd66079a3444"}, true}, + {"fail excluded uris", []string{"https://uuid.example.com/d325eda7-6356-4d60-b8f6-3d64724afeb3"}, true}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + csr, err := x509util.CreateCertificateRequest(tt.sans[0], tt.sans, signer) + if err != nil { + t.Fatal(err) + } + cert, err := ca.SignCSR(csr) + if err != nil { + t.Fatal(err) + } + + data := x509util.CreateTemplateData(tt.sans[0], tt.sans) + templateOption, err := provisioner.TemplateOptions(nil, data) + if err != nil { + t.Fatal(err) + } + + _, err = auth.Sign(csr, provisioner.SignOptions{}, templateOption) + if (err != nil) != tt.wantErr { + t.Errorf("Authority.Sign() error = %v, wantErr %v", err, tt.wantErr) + } + + _, err = auth.Renew(cert) + if (err != nil) != tt.wantErr { + t.Errorf("Authority.Renew() error = %v, wantErr %v", err, tt.wantErr) + } + }) + } +}