[FAB-3677] Identity validation

This change-set addressed FAB-3677 in the following way:
At MSP setup time, a certification tree T is constructed based
on the root CA and Intermediate CA certificates (after their
sanitization). The MSP instance then stores the number of
children each node in T has. An identity is valid only if
its corresponding certificates had been signed by a leaf of T.
Specific tests haves been added.

Change-Id: Ie7d07c2faadc76890eec151267172ed92db0af34
Signed-off-by: Angelo De Caro <adc@zurich.ibm.com>

msp/mspimpl.go

@@ -44,6 +44,12 @@ type bccspmsp struct {
 	// list of intermediate certs we trust
 	intermediateCerts []Identity
 
+	// certificationTreeInternalNodesMap whose keys correspond to the raw material
+	// (DER representation) of a certificate casted to a string, and whose values
+	// are boolean. True means that the certificate is an internal node of the certification tree.
+	// False means that the certificate corresponds to a leaf of the certification tree.
+	certificationTreeInternalNodesMap map[string]bool
+
 	// list of signing identities
 	signer SigningIdentity
 
@@ -311,26 +317,24 @@ func (msp *bccspmsp) Setup(conf1 *m.MSPConfig) error {
 		return errors.New("Expected at least one CA certificate")
 	}
 
-	// pre-create the verify options with roots and intermediates
-	// this is needed to make certificate sanitation working.
-	msp.opts = &x509.VerifyOptions{
-		Roots:         x509.NewCertPool(),
-		Intermediates: x509.NewCertPool(),
-	}
+	// pre-create the verify options with roots and intermediates.
+	// This is needed to make certificate sanitation working.
+	// Recall that sanitization is applied also to root CA and intermediate
+	// CA certificates. After their sanitization is done, the opts
+	// will be recreated using the sanitized certs.
+	msp.opts = &x509.VerifyOptions{Roots: x509.NewCertPool(), Intermediates: x509.NewCertPool()}
 	for _, v := range conf.RootCerts {
 		cert, err := msp.getCertFromPem(v)
 		if err != nil {
 			return err
 		}
-
 		msp.opts.Roots.AddCert(cert)
 	}
 	for _, v := range conf.IntermediateCerts {
 		cert, err := msp.getCertFromPem(v)
 		if err != nil {
 			return err
 		}
-
 		msp.opts.Intermediates.AddCert(cert)
 	}
 
@@ -357,6 +361,15 @@ func (msp *bccspmsp) Setup(conf1 *m.MSPConfig) error {
 		msp.intermediateCerts[i] = id
 	}
 
+	// root CA and intermediate CA certificates are sanitized, they can be reimported
+	msp.opts = &x509.VerifyOptions{Roots: x509.NewCertPool(), Intermediates: x509.NewCertPool()}
+	for _, id := range msp.rootCerts {
+		msp.opts.Roots.AddCert(id.(*identity).cert)
+	}
+	for _, id := range msp.intermediateCerts {
+		msp.opts.Intermediates.AddCert(id.(*identity).cert)
+	}
+
 	// make and fill the set of admin certs (if present)
 	msp.admins = make([]Identity, len(conf.Admins))
 	for i, admCert := range conf.Admins {
@@ -395,6 +408,21 @@ func (msp *bccspmsp) Setup(conf1 *m.MSPConfig) error {
 		}
 	}
 
+	// populate certificationTreeInternalNodesMap to mark the internal nodes of the
+	// certification tree
+	msp.certificationTreeInternalNodesMap = make(map[string]bool)
+	for _, cert := range append([]Identity{}, msp.intermediateCerts...) {
+		chain, err := msp.getUniqueValidationChain(cert.(*identity).cert)
+		if err != nil {
+			return fmt.Errorf("Failed getting validation chain, (SN: %s)", cert.(*identity).cert.SerialNumber)
+		}
+
+		// Recall chain[0] is cert.(*identity).cert so it does not count as a parent
+		for i := 1; i < len(chain); i++ {
+			msp.certificationTreeInternalNodesMap[string(chain[i].Raw)] = true
+		}
+	}
+
 	// setup the signer (if present)
 	if conf.SigningIdentity != nil {
 		sid, err := msp.getSigningIdentityFromConf(conf.SigningIdentity)
@@ -683,6 +711,11 @@ func (msp *bccspmsp) getValidationChain(cert *x509.Certificate) ([]*x509.Certifi
 		return nil, fmt.Errorf("Expected a chain of length at least 2, got %d", len(validationChain))
 	}
 
+	// check that the parent is a leaf of the certification tree
+	if msp.certificationTreeInternalNodesMap[string(validationChain[1].Raw)] {
+		return nil, fmt.Errorf("Invalid validation chain. Parent certificate should be a leaf of the certification tree [%v].", cert.Raw)
+	}
+
 	return validationChain, nil
 }
 

msp/mspwithintermediatecas_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package msp
 
 import (
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -63,3 +64,30 @@ func TestIntermediateCAIdentityValidity(t *testing.T) {
 	id := thisMSP.(*bccspmsp).intermediateCerts[0]
 	assert.Error(t, id.Validate())
 }
+
+func TestMSPWithIntermediateCAs2(t *testing.T) {
+	// testdata/intermediate2 contains the credentials for a test MSP setup that has
+	// 1) a key and a signcert (used to populate the default signing identity);
+	//    signcert is not signed by a CA directly but by an intermediate CA
+	// 2) intermediatecert is an intermediate CA, signed by the CA
+	// 3) cacert is the CA that signed the intermediate
+	// 4) user2-cert is the certificate of an identity signed directly by the CA
+	//    therefore validation should fail.
+	thisMSP := getLocalMSP(t, filepath.Join("testdata", "intermediate2"))
+
+	// the default signing identity is signed by the intermediate CA,
+	// the validation should return no error
+	id, err := thisMSP.GetDefaultSigningIdentity()
+	assert.NoError(t, err)
+	err = thisMSP.Validate(id.GetPublicVersion())
+	assert.NoError(t, err)
+
+	// user2-cert has been signed by the root CA, validation must fail
+	pem, err := readPemFile(filepath.Join("testdata", "intermediate2", "users", "user2-cert.pem"))
+	assert.NoError(t, err)
+	id2, _, err := thisMSP.(*bccspmsp).getIdentityFromConf(pem)
+	assert.NoError(t, err)
+	err = thisMSP.Validate(id2)
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "Invalid validation chain. Parent certificate should be a leaf of the certification tree ")
+}

msp/testdata/intermediate2/admincerts/admin.pem

@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----
+MIICLzCCAdagAwIBAgIQLcb0TM7r3ga3Z+o4nBRSFjAKBggqhkjOPQQDAjBJMQsw
+CQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy
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+swIgMdTefeOqQvpKY1VrCR3VUE3zOMKF5k2kruyr7gGdU3E=
+-----END CERTIFICATE-----

msp/testdata/intermediate2/cacerts/cacert.pem

@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----
+MIICEDCCAbegAwIBAgIQKy5yRZcslB/rn4imlQYAkzAKBggqhkjOPQQDAjBVMQsw
+CQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy
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+dRnXZnKUFiPJb2t00NGh6oKuAiAs5vlQ+6izRviSO7ujTNdsqjfs5WlCcesy5reV
+8F7esg==
+-----END CERTIFICATE-----

msp/testdata/intermediate2/intermediatecerts/intermediatecert.pem

@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE-----
+MIICbzCCAhWgAwIBAgIQKA9DhIj8YDJpbP7wFsmuSDAKBggqhkjOPQQDAjBVMQsw
+CQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy
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+Jmbfjm/qCOmLvt53HPa/B0ICIB2q1TE21KK68fxO6C92AhNuTmGHmumLB8yTBG7j
+QsQL
+-----END CERTIFICATE-----

msp/testdata/intermediate2/keystore/key.pem

@@ -0,0 +1,5 @@
+-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgTNlF7jY6jBKQGLqs
+AgllL7utSIRxZdxy4fexQaNX7JKhRANCAAT3WqE6zy7kgdDbN4Ecv+1ITEjFnOpJ
+52oi5lrBfXhFt+F12qLqSuYs0EqJL0VvbtKZMkdXAkgQB26ifAAvqtTn
+-----END PRIVATE KEY-----

msp/testdata/intermediate2/signcerts/signcert.pem

@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----
+MIICLzCCAdagAwIBAgIQLcb0TM7r3ga3Z+o4nBRSFjAKBggqhkjOPQQDAjBJMQsw
+CQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy
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+swIgMdTefeOqQvpKY1VrCR3VUE3zOMKF5k2kruyr7gGdU3E=
+-----END CERTIFICATE-----

msp/testdata/intermediate2/users/user2-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----
+MIIB/zCCAaagAwIBAgIRAO7SLOYTMXE76j8HsQvesuswCgYIKoZIzj0EAwIwVTEL
+MAkGA1UEBhMCVVMxEzARBgNVBAgTCkNhbGlmb3JuaWExFjAUBgNVBAcTDVNhbiBG
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+9gIgH5lA0xykOrvVyARyCO1u+6NebJsv2aUMdXJ7eJMjREE=
+-----END CERTIFICATE-----