diff --git a/src/pkg/crypto/x509/verify.go b/src/pkg/crypto/x509/verify.go index 307c5ef0339..91506e87bb0 100644 --- a/src/pkg/crypto/x509/verify.go +++ b/src/pkg/crypto/x509/verify.go @@ -27,6 +27,9 @@ const ( // TooManyIntermediates results when a path length constraint is // violated. TooManyIntermediates + // IncompatibleUsage results when the certificate's key usage indicates + // that it may only be used for a different purpose. + IncompatibleUsage ) // CertificateInvalidError results when an odd error occurs. Users of this @@ -46,6 +49,8 @@ func (e CertificateInvalidError) Error() string { return "x509: a root or intermediate certificate is not authorized to sign in this domain" case TooManyIntermediates: return "x509: too many intermediates for path length constraint" + case IncompatibleUsage: + return "x509: certificate specifies an incompatible key usage" } return "x509: unknown error" } @@ -84,6 +89,11 @@ type VerifyOptions struct { Intermediates *CertPool Roots *CertPool // if nil, the system roots are used CurrentTime time.Time // if zero, the current time is used + // KeyUsage specifies which Extended Key Usage values are acceptable. + // An empty list means ExtKeyUsageServerAuth. Key usage is considered a + // constraint down the chain which mirrors Windows CryptoAPI behaviour, + // but not the spec. To accept any key usage, include ExtKeyUsageAny. + KeyUsages []ExtKeyUsage } const ( @@ -174,7 +184,35 @@ func (c *Certificate) Verify(opts VerifyOptions) (chains [][]*Certificate, err e } } - return c.buildChains(make(map[int][][]*Certificate), []*Certificate{c}, &opts) + candidateChains, err := c.buildChains(make(map[int][][]*Certificate), []*Certificate{c}, &opts) + if err != nil { + return + } + + keyUsages := opts.KeyUsages + if len(keyUsages) == 0 { + keyUsages = []ExtKeyUsage{ExtKeyUsageServerAuth} + } + + // If any key usage is acceptable then we're done. + for _, usage := range keyUsages { + if usage == ExtKeyUsageAny { + chains = candidateChains + return + } + } + + for _, candidate := range candidateChains { + if checkChainForKeyUsage(candidate, keyUsages) { + chains = append(chains, candidate) + } + } + + if len(chains) == 0 { + err = CertificateInvalidError{c, IncompatibleUsage} + } + + return } func appendToFreshChain(chain []*Certificate, cert *Certificate) []*Certificate { @@ -300,3 +338,56 @@ func (c *Certificate) VerifyHostname(h string) error { return HostnameError{c, h} } + +func checkChainForKeyUsage(chain []*Certificate, keyUsages []ExtKeyUsage) bool { + usages := make([]ExtKeyUsage, len(keyUsages)) + copy(usages, keyUsages) + + if len(chain) == 0 { + return false + } + + usagesRemaining := len(usages) + + // We walk down the list and cross out any usages that aren't supported + // by each certificate. If we cross out all the usages, then the chain + // is unacceptable. + + for i := len(chain) - 1; i >= 0; i-- { + cert := chain[i] + if len(cert.ExtKeyUsage) == 0 && len(cert.UnknownExtKeyUsage) == 0 { + // The certificate doesn't have any extended key usage specified. + continue + } + + for _, usage := range cert.ExtKeyUsage { + if usage == ExtKeyUsageAny { + // The certificate is explicitly good for any usage. + continue + } + } + + const invalidUsage ExtKeyUsage = -1 + + NextRequestedUsage: + for i, requestedUsage := range usages { + if requestedUsage == invalidUsage { + continue + } + + for _, usage := range cert.ExtKeyUsage { + if requestedUsage == usage { + continue NextRequestedUsage + } + } + + usages[i] = invalidUsage + usagesRemaining-- + if usagesRemaining == 0 { + return false + } + } + } + + return true +} diff --git a/src/pkg/crypto/x509/verify_test.go b/src/pkg/crypto/x509/verify_test.go index 7b171b291a4..510a119ff7c 100644 --- a/src/pkg/crypto/x509/verify_test.go +++ b/src/pkg/crypto/x509/verify_test.go @@ -21,6 +21,7 @@ type verifyTest struct { currentTime int64 dnsName string systemSkip bool + keyUsages []ExtKeyUsage errorCallback func(*testing.T, int, error) bool expectedChains [][]string @@ -113,6 +114,38 @@ var verifyTests = []verifyTest{ {"dnssec-exp", "StartCom Class 1", "StartCom Certification Authority", "StartCom Certification Authority"}, }, }, + { + // The default configuration should reject an S/MIME chain. + leaf: smimeLeaf, + roots: []string{smimeIntermediate}, + currentTime: 1339436154, + + // Key usage not implemented for Windows yet. + systemSkip: true, + errorCallback: expectUsageError, + }, + { + leaf: smimeLeaf, + roots: []string{smimeIntermediate}, + currentTime: 1339436154, + keyUsages: []ExtKeyUsage{ExtKeyUsageServerAuth}, + + // Key usage not implemented for Windows yet. + systemSkip: true, + errorCallback: expectUsageError, + }, + { + leaf: smimeLeaf, + roots: []string{smimeIntermediate}, + currentTime: 1339436154, + keyUsages: []ExtKeyUsage{ExtKeyUsageEmailProtection}, + + // Key usage not implemented for Windows yet. + systemSkip: true, + expectedChains: [][]string{ + {"Ryan Hurst", "GlobalSign PersonalSign 2 CA - G2"}, + }, + }, } func expectHostnameError(t *testing.T, i int, err error) (ok bool) { @@ -131,6 +164,14 @@ func expectExpired(t *testing.T, i int, err error) (ok bool) { return true } +func expectUsageError(t *testing.T, i int, err error) (ok bool) { + if inval, ok := err.(CertificateInvalidError); !ok || inval.Reason != IncompatibleUsage { + t.Errorf("#%d: error was not IncompatibleUsage: %s", i, err) + return false + } + return true +} + func expectAuthorityUnknown(t *testing.T, i int, err error) (ok bool) { if _, ok := err.(UnknownAuthorityError); !ok { t.Errorf("#%d: error was not UnknownAuthorityError: %s", i, err) @@ -157,6 +198,7 @@ func testVerify(t *testing.T, useSystemRoots bool) { Intermediates: NewCertPool(), DNSName: test.dnsName, CurrentTime: time.Unix(test.currentTime, 0), + KeyUsages: test.keyUsages, } if !useSystemRoots { @@ -433,3 +475,58 @@ O3NJo2pXh5Tl1njFmUNj403gdy3hZZlyaQQaRwnmDwFWJPsfvw55qVguucQJAX6V um0ABj6y6koQOdjQK/W/7HW/lwLFCRsI3FU34oH7N4RDYiDK51ZLZer+bMEkkySh NOsF/5oirpt9P/FlUQqmMGqz9IgcgA38corog14= -----END CERTIFICATE-----` + +const smimeLeaf = `-----BEGIN CERTIFICATE----- +MIIFBjCCA+6gAwIBAgISESFvrjT8XcJTEe6rBlPptILlMA0GCSqGSIb3DQEBBQUA +MFQxCzAJBgNVBAYTAkJFMRkwFwYDVQQKExBHbG9iYWxTaWduIG52LXNhMSowKAYD +VQQDEyFHbG9iYWxTaWduIFBlcnNvbmFsU2lnbiAyIENBIC0gRzIwHhcNMTIwMTIz +MTYzNjU5WhcNMTUwMTIzMTYzNjU5WjCBlDELMAkGA1UEBhMCVVMxFjAUBgNVBAgT +DU5ldyBIYW1zcGhpcmUxEzARBgNVBAcTClBvcnRzbW91dGgxGTAXBgNVBAoTEEds +b2JhbFNpZ24sIEluYy4xEzARBgNVBAMTClJ5YW4gSHVyc3QxKDAmBgkqhkiG9w0B +CQEWGXJ5YW4uaHVyc3RAZ2xvYmFsc2lnbi5jb20wggEiMA0GCSqGSIb3DQEBAQUA +A4IBDwAwggEKAoIBAQC4ASSTvavmsFQAob60ukSSwOAL9nT/s99ltNUCAf5fPH5j +NceMKxaQse2miOmRRIXaykcq1p/TbI70Ztce38r2mbOwqDHHPVi13GxJEyUXWgaR +BteDMu5OGyWNG1kchVsGWpbstT0Z4v0md5m1BYFnxB20ebJyOR2lXDxsFK28nnKV ++5eMj76U8BpPQ4SCH7yTMG6y0XXsB3cCrBKr2o3TOYgEKv+oNnbaoMt3UxMt9nSf +9jyIshjqfnT5Aew3CUNMatO55g5FXXdIukAweg1YSb1ls05qW3sW00T3d7dQs9/7 +NuxCg/A2elmVJSoy8+MLR8JSFEf/aMgjO/TyLg/jAgMBAAGjggGPMIIBizAOBgNV +HQ8BAf8EBAMCBaAwTQYDVR0gBEYwRDBCBgorBgEEAaAyASgKMDQwMgYIKwYBBQUH +AgEWJmh0dHBzOi8vd3d3Lmdsb2JhbHNpZ24uY29tL3JlcG9zaXRvcnkvMCQGA1Ud +EQQdMBuBGXJ5YW4uaHVyc3RAZ2xvYmFsc2lnbi5jb20wCQYDVR0TBAIwADAdBgNV +HSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwQwQwYDVR0fBDwwOjA4oDagNIYyaHR0 +cDovL2NybC5nbG9iYWxzaWduLmNvbS9ncy9nc3BlcnNvbmFsc2lnbjJnMi5jcmww +VQYIKwYBBQUHAQEESTBHMEUGCCsGAQUFBzAChjlodHRwOi8vc2VjdXJlLmdsb2Jh +bHNpZ24uY29tL2NhY2VydC9nc3BlcnNvbmFsc2lnbjJnMi5jcnQwHQYDVR0OBBYE +FFWiECe0/L72eVYqcWYnLV6SSjzhMB8GA1UdIwQYMBaAFD8V0m18L+cxnkMKBqiU +bCw7xe5lMA0GCSqGSIb3DQEBBQUAA4IBAQAhQi6hLPeudmf3IBF4IDzCvRI0FaYd +BKfprSk/H0PDea4vpsLbWpA0t0SaijiJYtxKjlM4bPd+2chb7ejatDdyrZIzmDVy +q4c30/xMninGKokpYA11/Ve+i2dvjulu65qasrtQRGybAuuZ67lrp/K3OMFgjV5N +C3AHYLzvNU4Dwc4QQ1BaMOg6KzYSrKbABRZajfrpC9uiePsv7mDIXLx/toBPxWNl +a5vJm5DrZdn7uHdvBCE6kMykbOLN5pmEK0UIlwKh6Qi5XD0pzlVkEZliFkBMJgub +d/eF7xeg7TKPWC5xyOFp9SdMolJM7LTC3wnSO3frBAev+q/nGs9Xxyvs +-----END CERTIFICATE-----` + +const smimeIntermediate = `-----BEGIN CERTIFICATE----- +MIIEFjCCAv6gAwIBAgILBAAAAAABL07hL1IwDQYJKoZIhvcNAQEFBQAwVzELMAkG +A1UEBhMCQkUxGTAXBgNVBAoTEEdsb2JhbFNpZ24gbnYtc2ExEDAOBgNVBAsTB1Jv +b3QgQ0ExGzAZBgNVBAMTEkdsb2JhbFNpZ24gUm9vdCBDQTAeFw0xMTA0MTMxMDAw +MDBaFw0xOTA0MTMxMDAwMDBaMFQxCzAJBgNVBAYTAkJFMRkwFwYDVQQKExBHbG9i +YWxTaWduIG52LXNhMSowKAYDVQQDEyFHbG9iYWxTaWduIFBlcnNvbmFsU2lnbiAy +IENBIC0gRzIwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDBa0H5Nez4 +En3dIlFpX7e5E0YndxQ74xOBbz7kdBd+DLX0LOQMjVPU3DAgKL9ujhH+ZhHkURbH +3X/94TQSUL/z2JjsaQvS0NqyZXHhM5eeuquzOJRzEQ8+odETzHg2G0Erv7yjSeww +gkwDWDJnYUDlOjYTDUEG6+i+8Mn425reo4I0E277wD542kmVWeW7+oHv5dZo9e1Q +yWwiKTEP6BEQVVSBgThXMG4traSSDRUt3T1eQTZx5EObpiBEBO4OTqiBTJfg4vEI +YgkXzKLpnfszTB6YMDpR9/QS6p3ANB3kfAb+t6udSO3WCst0DGrwHDLBFGDR4UeY +T5KGGnI7cWL7AgMBAAGjgeUwgeIwDgYDVR0PAQH/BAQDAgEGMBIGA1UdEwEB/wQI +MAYBAf8CAQAwHQYDVR0OBBYEFD8V0m18L+cxnkMKBqiUbCw7xe5lMEcGA1UdIARA +MD4wPAYEVR0gADA0MDIGCCsGAQUFBwIBFiZodHRwczovL3d3dy5nbG9iYWxzaWdu +LmNvbS9yZXBvc2l0b3J5LzAzBgNVHR8ELDAqMCigJqAkhiJodHRwOi8vY3JsLmds +b2JhbHNpZ24ubmV0L3Jvb3QuY3JsMB8GA1UdIwQYMBaAFGB7ZhpFDZfKiVAvfQTN +NKj//P1LMA0GCSqGSIb3DQEBBQUAA4IBAQBDc3nMpMxJMQMcYUCB3+C73UpvwDE8 +eCOr7t2F/uaQKKcyqqstqLZc6vPwI/rcE9oDHugY5QEjQzIBIEaTnN6P0vege2IX +eCOr7t2F/uaQKKcyqqstqLZc6vPwI/rcE9oDHugY5QEjQzIBIEaTnN6P0vege2IX +YEvTWbWwGdPytDFPYIl3/6OqNSXSnZ7DxPcdLJq2uyiga8PB/TTIIHYkdM2+1DE0 +7y3rH/7TjwDVD7SLu5/SdOfKskuMPTjOEvz3K161mymW06klVhubCIWOro/Gx1Q2 +2FQOZ7/2k4uYoOdBTSlb8kTAuzZNgIE0rB2BIYCTz/P6zZIKW0ogbRSH +-----END CERTIFICATE-----` diff --git a/src/pkg/crypto/x509/x509.go b/src/pkg/crypto/x509/x509.go index 6848bf801d4..24e2ae1d8ae 100644 --- a/src/pkg/crypto/x509/x509.go +++ b/src/pkg/crypto/x509/x509.go @@ -350,6 +350,9 @@ var ( oidExtKeyUsageClientAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 2} oidExtKeyUsageCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 3} oidExtKeyUsageEmailProtection = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 4} + oidExtKeyUsageIPSECEndSystem = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 5} + oidExtKeyUsageIPSECTunnel = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 6} + oidExtKeyUsageIPSECUser = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 7} oidExtKeyUsageTimeStamping = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 8} oidExtKeyUsageOCSPSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 9} ) @@ -364,6 +367,9 @@ const ( ExtKeyUsageClientAuth ExtKeyUsageCodeSigning ExtKeyUsageEmailProtection + ExtKeyUsageIPSECEndSystem + ExtKeyUsageIPSECTunnel + ExtKeyUsageIPSECUser ExtKeyUsageTimeStamping ExtKeyUsageOCSPSigning ) @@ -806,6 +812,12 @@ func parseCertificate(in *certificate) (*Certificate, error) { out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageCodeSigning) case u.Equal(oidExtKeyUsageEmailProtection): out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageEmailProtection) + case u.Equal(oidExtKeyUsageIPSECEndSystem): + out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageIPSECEndSystem) + case u.Equal(oidExtKeyUsageIPSECTunnel): + out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageIPSECTunnel) + case u.Equal(oidExtKeyUsageIPSECUser): + out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageIPSECUser) case u.Equal(oidExtKeyUsageTimeStamping): out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageTimeStamping) case u.Equal(oidExtKeyUsageOCSPSigning):