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Implement query signature verification #449
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,141 @@ | ||
package saml | ||
|
||
import ( | ||
"crypto" | ||
"crypto/rsa" | ||
"crypto/sha1" // #nosec G505 | ||
"crypto/sha256" | ||
"crypto/sha512" | ||
"crypto/x509" | ||
"encoding/base64" | ||
"errors" | ||
"fmt" | ||
"net/url" | ||
|
||
dsig "github.com/russellhaering/goxmldsig" | ||
) | ||
|
||
type reqType string | ||
|
||
const ( | ||
samlRequest reqType = "SAMLRequest" | ||
samlResponse reqType = "SAMLResponse" | ||
) | ||
|
||
var ( | ||
// ErrInvalidQuerySignature is returned when the query signature is invalid | ||
ErrInvalidQuerySignature = errors.New("invalid query signature") | ||
// ErrNoQuerySignature is returned when the query does not contain a signature | ||
ErrNoQuerySignature = errors.New("query Signature or SigAlg not found") | ||
) | ||
|
||
// Sign Query with the SP private key. | ||
// Returns provided query with the SigAlg and Signature parameters added. | ||
func (sp *ServiceProvider) signQuery(reqT reqType, query, body, relayState string) (string, error) { | ||
signingContext, err := GetSigningContext(sp) | ||
|
||
// Encode Query as standard demands. query.Encode() is not standard compliant | ||
toHash := string(reqT) + "=" + url.QueryEscape(body) | ||
if relayState != "" { | ||
toHash += "&RelayState=" + url.QueryEscape(relayState) | ||
} | ||
|
||
toHash += "&SigAlg=" + url.QueryEscape(sp.SignatureMethod) | ||
|
||
if err != nil { | ||
return "", err | ||
} | ||
|
||
sig, err := signingContext.SignString(toHash) | ||
if err != nil { | ||
return "", err | ||
} | ||
|
||
query += "&SigAlg=" + url.QueryEscape(sp.SignatureMethod) | ||
query += "&Signature=" + url.QueryEscape(base64.StdEncoding.EncodeToString(sig)) | ||
|
||
return query, nil | ||
} | ||
|
||
// validateSig validation of the signature of the Redirect Binding in query values | ||
// Query is valid if return is nil | ||
func (sp *ServiceProvider) validateQuerySig(query url.Values) error { | ||
sig := query.Get("Signature") | ||
alg := query.Get("SigAlg") | ||
if sig == "" || alg == "" { | ||
return ErrNoQuerySignature | ||
} | ||
|
||
certs, err := sp.getIDPSigningCerts() | ||
if err != nil { | ||
return err | ||
} | ||
|
||
respType := "" | ||
if query.Get("SAMLResponse") != "" { | ||
respType = "SAMLResponse" | ||
} else if query.Get("SAMLRequest") != "" { | ||
respType = "SAMLRequest" | ||
} else { | ||
return fmt.Errorf("No SAMLResponse or SAMLRequest found in query") | ||
} | ||
|
||
// Encode Query as standard demands. | ||
// query.Encode() is not standard compliant | ||
// as query encoding order matters | ||
res := respType + "=" + url.QueryEscape(query.Get(respType)) | ||
|
||
relayState := query.Get("RelayState") | ||
if relayState != "" { | ||
res += "&RelayState=" + url.QueryEscape(relayState) | ||
} | ||
|
||
res += "&SigAlg=" + url.QueryEscape(alg) | ||
|
||
// Signature is base64 encoded | ||
sigBytes, err := base64.StdEncoding.DecodeString(sig) | ||
if err != nil { | ||
return fmt.Errorf("failed to decode signature: %w", err) | ||
} | ||
|
||
var ( | ||
hashed []byte | ||
hashAlg crypto.Hash | ||
sigAlg x509.SignatureAlgorithm | ||
) | ||
|
||
// Hashed Query | ||
switch alg { | ||
case dsig.RSASHA256SignatureMethod: | ||
hashed256 := sha256.Sum256([]byte(res)) | ||
hashed = hashed256[:] | ||
hashAlg = crypto.SHA256 | ||
sigAlg = x509.SHA256WithRSA | ||
case dsig.RSASHA512SignatureMethod: | ||
hashed512 := sha512.Sum512([]byte(res)) | ||
hashed = hashed512[:] | ||
hashAlg = crypto.SHA512 | ||
sigAlg = x509.SHA512WithRSA | ||
case dsig.RSASHA1SignatureMethod: | ||
hashed1 := sha1.Sum([]byte(res)) // #nosec G401 | ||
hashed = hashed1[:] | ||
hashAlg = crypto.SHA1 | ||
sigAlg = x509.SHA1WithRSA | ||
default: | ||
return fmt.Errorf("unsupported signature algorithm: %s", alg) | ||
} | ||
|
||
// validate signature | ||
for _, cert := range certs { | ||
// verify cert is RSA | ||
if cert.SignatureAlgorithm != sigAlg { | ||
continue | ||
} | ||
|
||
if err := rsa.VerifyPKCS1v15(cert.PublicKey.(*rsa.PublicKey), hashAlg, hashed, sigBytes); err == nil { | ||
return nil | ||
} | ||
} | ||
|
||
return ErrInvalidQuerySignature | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,117 @@ | ||
package saml | ||
|
||
import ( | ||
"crypto/rsa" | ||
"encoding/base64" | ||
"encoding/xml" | ||
"net/url" | ||
"testing" | ||
|
||
dsig "github.com/russellhaering/goxmldsig" | ||
"gotest.tools/assert" | ||
"gotest.tools/golden" | ||
) | ||
|
||
// Given a SAMLRequest query string, sign the query and validate signature | ||
// Using same Cert for SP and IdP in order to test | ||
func TestSigningAndValidation(t *testing.T) { | ||
type testCase struct { | ||
desc string | ||
relayState string | ||
requestType reqType | ||
wantErr bool | ||
wantRawQuery string | ||
} | ||
|
||
testCases := []testCase{ | ||
{ | ||
desc: "validate signature of SAMLRequest with relayState", | ||
relayState: "AAAAAAAAAAAA", | ||
requestType: samlRequest, | ||
wantRawQuery: "SAMLRequest=PHNhbWxwOkF1dGhuUmVxdWVzdCB4bWxuczpzYW1sPSJ1cm46b2FzaXM6bmFtZXM6dGM6U0FNTDoyLjA6YXNzZXJ0aW9uIiB4bWxuczpzYW1scD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOnByb3RvY29sIiBJRD0iaWQtMDAwMjA0MDYwODBhMGMwZTEwMTIxNDE2MTgxYTFjMWUyMDIyMjQyNiIgVmVyc2lvbj0iMi4wIiBJc3N1ZUluc3RhbnQ9IjIwMTUtMTItMDFUMDE6NTc6MDlaIiBEZXN0aW5hdGlvbj0iaHR0cHM6Ly9pZHAuZXhhbXBsZS5jb20vc2FtbC9zc28iIEFzc2VydGlvbkNvbnN1bWVyU2VydmljZVVSTD0iaHR0cHM6Ly9zcC5leGFtcGxlLmNvbS9zYW1sMi9hY3MiIFByb3RvY29sQmluZGluZz0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOmJpbmRpbmdzOkhUVFAtUE9TVCI%2BPHNhbWw6SXNzdWVyIEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6ZW50aXR5Ij5odHRwczovL3NwLmV4YW1wbGUuY29tL3NhbWwyL21ldGFkYXRhPC9zYW1sOklzc3Vlcj48c2FtbHA6TmFtZUlEUG9saWN5IEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6dHJhbnNpZW50IiBBbGxvd0NyZWF0ZT0idHJ1ZSIvPjwvc2FtbHA6QXV0aG5SZXF1ZXN0Pg%3D%3D&RelayState=AAAAAAAAAAAA&SigAlg=http%3A%2F%2Fwww.w3.org%2F2000%2F09%2Fxmldsig%23rsa-sha1&Signature=zWAF4S%2FIs7tfmEriOsT5Fm8EFOGS3iCq6OxP5i7hM%2BMPwAoXwdDz6fKH8euS1gQ3sGOZBdHD588FZLvnO1OeCxLaEsxHMVKsAZSZFLBmPPwqB6e%2B84cCwX2szOeoMROaR%2B36mdoBDRQz36JIvyBBG%2FND9x41k%2FGQuAuwk%2B9fkuE%3D", | ||
}, | ||
{ | ||
desc: "validate signature of SAML request without relay state", | ||
relayState: "", | ||
requestType: samlRequest, | ||
wantRawQuery: "SAMLRequest=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%2BPHNhbWw6SXNzdWVyIEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6ZW50aXR5Ij5odHRwczovL3NwLmV4YW1wbGUuY29tL3NhbWwyL21ldGFkYXRhPC9zYW1sOklzc3Vlcj48c2FtbHA6TmFtZUlEUG9saWN5IEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6dHJhbnNpZW50IiBBbGxvd0NyZWF0ZT0idHJ1ZSIvPjwvc2FtbHA6QXV0aG5SZXF1ZXN0Pg%3D%3D&SigAlg=http%3A%2F%2Fwww.w3.org%2F2000%2F09%2Fxmldsig%23rsa-sha1&Signature=HDdoHJSdkYh9%2BmE7RZ1LXcsAWIMJ6LuzKJgwLxH%2BQ4sKFlh8b5moFuQ%2B7rPEwoTcg9SjgCGV5rW9v8PrSU7WGKcLfAbeVwXWyU94ghjFZHEj%2BFCDpsfTD750ZPAPVnhVr0GogFZZ7c%2BEWX4NAqL4CYxDvsg56o%2BpOjw62G%2FyPDc%3D", | ||
}, | ||
{ | ||
desc: "validate signature of SAML response with relay state", | ||
relayState: "AAAAAAAAAAAA", | ||
requestType: samlResponse, | ||
wantRawQuery: "SAMLResponse=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%2BPHNhbWw6SXNzdWVyIEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6ZW50aXR5Ij5odHRwczovL3NwLmV4YW1wbGUuY29tL3NhbWwyL21ldGFkYXRhPC9zYW1sOklzc3Vlcj48c2FtbHA6TmFtZUlEUG9saWN5IEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6dHJhbnNpZW50IiBBbGxvd0NyZWF0ZT0idHJ1ZSIvPjwvc2FtbHA6QXV0aG5SZXF1ZXN0Pg%3D%3D&RelayState=AAAAAAAAAAAA&SigAlg=http%3A%2F%2Fwww.w3.org%2F2000%2F09%2Fxmldsig%23rsa-sha1&Signature=JDeiWfLgV7SZqgqU64wgtAHS%2FqtF2c3c%2B9g1vdfRHn03tm5jrgsvJtIYg1BD8HoejCoyruH3xgDz1i2qqecVcUiAdaVgVvhn0JWJ%2BzeN9YpUFTEQ4Ah1pwezlSArzuz5esgYzSkemViox313HePWZ%2Fd0FAmtdXuGHA8O0Lp%2F4Ws%3D", | ||
}, | ||
} | ||
|
||
idpMetadata := golden.Get(t, "SP_IDPMetadata_signing") | ||
s := ServiceProvider{ | ||
Key: mustParsePrivateKey(golden.Get(t, "idp_key.pem")).(*rsa.PrivateKey), | ||
Certificate: mustParseCertificate(golden.Get(t, "idp_cert.pem")), | ||
MetadataURL: mustParseURL("https://15661444.ngrok.io/saml2/metadata"), | ||
AcsURL: mustParseURL("https://15661444.ngrok.io/saml2/acs"), | ||
SignatureMethod: dsig.RSASHA1SignatureMethod, | ||
} | ||
|
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err := xml.Unmarshal(idpMetadata, &s.IDPMetadata) | ||
idpCert, err := s.getIDPSigningCerts() | ||
|
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assert.Check(t, err == nil) | ||
assert.Check(t, | ||
s.Certificate.Issuer.CommonName == idpCert[0].Issuer.CommonName, "expected %s, got %s", | ||
s.Certificate.Issuer.CommonName, idpCert[0].Issuer.CommonName) | ||
|
||
req := golden.Get(t, "idp_authn_request.xml") | ||
reqString := base64.StdEncoding.EncodeToString(req) | ||
|
||
for _, tc := range testCases { | ||
t.Run(tc.desc, func(t *testing.T) { | ||
relayState := tc.relayState | ||
|
||
rawQuery := string(tc.requestType) + "=" + url.QueryEscape(reqString) | ||
|
||
if relayState != "" { | ||
rawQuery += "&RelayState=" + relayState | ||
} | ||
|
||
rawQuery, err = s.signQuery(tc.requestType, rawQuery, reqString, relayState) | ||
assert.NilError(t, err, "error signing query: %s", err) | ||
|
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assert.Equal(t, tc.wantRawQuery, rawQuery) | ||
|
||
query, err := url.ParseQuery(rawQuery) | ||
assert.NilError(t, err, "error parsing query: %s", err) | ||
|
||
err = s.validateQuerySig(query) | ||
assert.NilError(t, err, "error validating query: %s", err) | ||
}) | ||
} | ||
} | ||
|
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// Given a raw query with an unsupported signature method, the signature should be rejected. | ||
func TestInvalidSignatureAlgorithm(t *testing.T) { | ||
rawQuery := "SAMLRequest=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%2BPHNhbWw6SXNzdWVyIEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6ZW50aXR5Ij5odHRwczovL3NwLmV4YW1wbGUuY29tL3NhbWwyL21ldGFkYXRhPC9zYW1sOklzc3Vlcj48c2FtbHA6TmFtZUlEUG9saWN5IEZvcm1hdD0idXJuOm9hc2lzOm5hbWVzOnRjOlNBTUw6Mi4wOm5hbWVpZC1mb3JtYXQ6dHJhbnNpZW50IiBBbGxvd0NyZWF0ZT0idHJ1ZSIvPjwvc2FtbHA6QXV0aG5SZXF1ZXN0Pg%3D%3D&RelayState=AAAAAAAAAAAA&SigAlg=http%3A%2F%2Fwww.w3.org%2F2000%2F09%2Fxmldsig%23rsa-sha384&Signature=zWAF4S%2FIs7tfmEriOsT5Fm8EFOGS3iCq6OxP5i7hM%2BMPwAoXwdDz6fKH8euS1gQ3sGOZBdHD588FZLvnO1OeCxLaEsxHMVKsAZSZFLBmPPwqB6e%2B84cCwX2szOeoMROaR%2B36mdoBDRQz36JIvyBBG%2FND9x41k%2FGQuAuwk%2B9fkuE%3D" | ||
|
||
idpMetadata := golden.Get(t, "SP_IDPMetadata_signing") | ||
s := ServiceProvider{ | ||
Key: mustParsePrivateKey(golden.Get(t, "idp_key.pem")).(*rsa.PrivateKey), | ||
Certificate: mustParseCertificate(golden.Get(t, "idp_cert.pem")), | ||
MetadataURL: mustParseURL("https://15661444.ngrok.io/saml2/metadata"), | ||
AcsURL: mustParseURL("https://15661444.ngrok.io/saml2/acs"), | ||
SignatureMethod: dsig.RSASHA1SignatureMethod, | ||
} | ||
|
||
err := xml.Unmarshal(idpMetadata, &s.IDPMetadata) | ||
idpCert, err := s.getIDPSigningCerts() | ||
|
||
assert.Check(t, err == nil) | ||
assert.Check(t, | ||
s.Certificate.Issuer.CommonName == idpCert[0].Issuer.CommonName, "expected %s, got %s", | ||
s.Certificate.Issuer.CommonName, idpCert[0].Issuer.CommonName) | ||
|
||
query, err := url.ParseQuery(rawQuery) | ||
assert.NilError(t, err, "error parsing query: %s", err) | ||
|
||
err = s.validateQuerySig(query) | ||
assert.Error(t, err, "unsupported signature algorithm: http://www.w3.org/2000/09/xmldsig#rsa-sha384") | ||
} |
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