Merge pull request #15 from maditya/ec-p11

add support for signing with ECDSA P256 key

docker-softhsm/crypki.conf.sample

@@ -1,21 +1,56 @@
 {
-  "ModulePath": "/usr/lib/x86_64-linux-gnu/softhsm/libsofthsm2.so",
-  "SSHUserInfo": {"KeyLabel": "user_ssh", "SlotNumber": SLOTNUM_USER_SSH, "UserPinPath" : "/dev/shm/slot_pwd.txt"},               
-	"X509Info": {"KeyLabel": "host_x509", "SlotNumber": SLOTNUM_HOST_X509, "UserPinPath" : "/dev/shm/slot_pwd.txt"},
-	"SSHHostInfo": {"KeyLabel": "host_ssh", "SlotNumber": SLOTNUM_HOST_SSH, "UserPinPath" : "/dev/shm/slot_pwd.txt"},
-  "TLSServerName": "localhost",
-  "TLSClientAuthMode": 4,
-	"TLSServerCertPath": "/opt/crypki/tls-crt/server.crt",
-	"TLSServerKeyPath": "/opt/crypki/tls-crt/server.key",
-	"TLSCACertPath": "/opt/crypki/tls-crt/ca.crt",
-  "Keys": [
-    {"Identifier": "ssh-user-key", "KeyLabel": "user_ssh", "SlotNumber": SLOTNUM_USER_SSH, "UserPinPath" : "/dev/shm/slot_pwd.txt"},
-		{"Identifier": "x509-key", "KeyLabel": "host_x509", "SlotNumber": SLOTNUM_HOST_X509, "UserPinPath" : "/dev/shm/slot_pwd.txt", "X509CACertLocation": "/opt/crypki/x509_ca.crt", "CreateCACertIfNotExist": true, "Country": "US", "State": "Some-State", "Locality": "Example", "Organization": "Example! Inc.", "OrganizationalUnit": "Example"},
-		{"Identifier": "ssh-host-key", "KeyLabel": "host_ssh", "SlotNumber": SLOTNUM_HOST_SSH, "UserPinPath" : "/dev/shm/slot_pwd.txt"}
-  ],
-  "KeyUsages": [
-    {"Endpoint": "/sig/ssh-user-cert", "Identifiers": ["ssh-user-key"]},
-		{"Endpoint": "/sig/x509-cert", "Identifiers": ["x509-key"]},
-		{"Endpoint": "/sig/ssh-host-cert", "Identifiers": ["ssh-host-key"]}
-  ]
+    "KeyUsages": [
+        {
+            "Endpoint": "/sig/ssh-user-cert",
+            "Identifiers": [
+                "ssh-user-key"
+            ]
+        },
+        {
+            "Endpoint": "/sig/x509-cert",
+            "Identifiers": [
+                "x509-key"
+            ]
+        },
+        {
+            "Endpoint": "/sig/ssh-host-cert",
+            "Identifiers": [
+                "ssh-host-key"
+            ]
+        }
+    ],
+    "Keys": [
+        {
+            "Identifier": "ssh-user-key",
+            "KeyLabel": "user_ssh",
+            "SlotNumber": SLOTNUM_USER_SSH,
+            "UserPinPath": "/dev/shm/slot_pwd.txt"
+        },
+        {
+            "Country": "US",
+            "CreateCACertIfNotExist": true,
+            "Identifier": "x509-key",
+            "KeyLabel": "host_x509",
+            "KeyType": 2,
+            "Locality": "Example",
+            "Organization": "Example! Inc.",
+            "OrganizationalUnit": "Example",
+            "SlotNumber": SLOTNUM_HOST_X509,
+            "State": "Some-State",
+            "UserPinPath": "/dev/shm/slot_pwd.txt",
+            "X509CACertLocation": "/opt/crypki/x509_ca.crt"
+        },
+        {
+            "Identifier": "ssh-host-key",
+            "KeyLabel": "host_ssh",
+            "SlotNumber": SLOTNUM_HOST_SSH,
+            "UserPinPath": "/dev/shm/slot_pwd.txt"
+        }
+    ],
+    "ModulePath": "/usr/lib/x86_64-linux-gnu/softhsm/libsofthsm2.so",
+    "TLSCACertPath": "/opt/crypki/tls-crt/ca.crt",
+    "TLSClientAuthMode": 4,
+    "TLSServerCertPath": "/opt/crypki/tls-crt/server.crt",
+    "TLSServerKeyPath": "/opt/crypki/tls-crt/server.key",
+    "TLSServerName": "localhost"
 }

docker-softhsm/init_hsm.sh

@@ -10,23 +10,32 @@ error() {
 SOPIN=1234
 USERPIN=123456
 
+modulepath="/usr/lib/x86_64-linux-gnu/softhsm/libsofthsm2.so"
+
+user_ssh_label="user_ssh"
+host_x509_label="host_x509"
+host_ssh_label="host_ssh"
+user_ssh_keytype="rsa:4096"
+host_x509_keytype="EC:prime256v1"
+host_ssh_keytype="rsa:4096"
+
 #
-# check for needed binaries/etc, provide "helpful" advice
+# check for required binaries and libraries
 #
 if [ "`uname -s`" != "Linux" ]; then
-	error "This only works on linux because the binaries and librarys are only available there."
+	error "This only works on linux because required binaries and libraries are only available and tested on linux."
 fi
 p11tool="`which pkcs11-tool 2>/dev/null`"
 p11tool="${p11tool:=/usr/bin/pkcs11-tool}"
 if [ ! -x "${p11tool}" ]; then
-	error "Can't find pkcs11-tool binary in path or /usr/bin/pkcs11-tool. Needed to configure the HSM.
-	yum -y install opensc # (or local equivalent rpm)"
+	error "Can't find pkcs11-tool binary in path or /usr/bin/pkcs11-tool. Needed to configure the HSM/PKCS#11 device.
+	yum -y install opensc or apt-get install opensc # (or local equivalent package)"
 fi
 softhsm="`which softhsm2-util 2>/dev/null`"
 softhsm="${softhsm:=/usr/bin/softhsm2-util}"
 if [ ! -x "${softhsm}" ]; then
-	error "Can't find softhsm binary in path or /usr/bin/softhsm2-util. Needed to configure the HSM.
-	yum -y install softhsm # (or local equivalent rpm)"
+	error "Can't find softhsm binary in path or /usr/bin/softhsm2-util. Needed to configure the HSM/PKCS#11 device.
+	yum -y install softhsm or apt-get install softhsm # (or local equivalent package)"
 fi
 
 set -e # exit if anything at all fails after here
@@ -38,11 +47,10 @@ user_ssh_slot=`${softhsm} --init-token --slot 0 --label user_ssh --so-pin ${SOPI
 host_x509_slot=`${softhsm} --init-token --slot 1 --label host_x509 --so-pin ${SOPIN} --pin ${USERPIN} | awk '{print $NF}'`
 host_ssh_slot=`${softhsm} --init-token --slot 2 --label host_ssh --so-pin ${SOPIN} --pin ${USERPIN} | awk '{print $NF}'`
 
-modulepath="/usr/lib/x86_64-linux-gnu/softhsm/libsofthsm2.so"
 # Generate the Keys in the PKCS11 slot
-${p11tool} --module ${modulepath} --pin 123456 --slot ${user_ssh_slot} --keypairgen --label "user_ssh" --key-type rsa:4096 --private
-${p11tool} --module ${modulepath} --pin 123456 --slot ${host_x509_slot} --keypairgen --label "host_x509" --key-type rsa:4096 --private
-${p11tool} --module ${modulepath} --pin 123456 --slot ${host_ssh_slot} --keypairgen --label "host_ssh" --key-type rsa:4096 --private
+${p11tool} --module ${modulepath} --pin ${USERPIN} --slot ${user_ssh_slot} --keypairgen --label ${user_ssh_label} --key-type ${user_ssh_keytype} --private
+${p11tool} --module ${modulepath} --pin ${USERPIN} --slot ${host_x509_slot} --keypairgen --label ${host_x509_label} --key-type ${host_x509_keytype} --private
+${p11tool} --module ${modulepath} --pin ${USERPIN} --slot ${host_ssh_slot} --keypairgen --label ${host_ssh_label} --key-type ${host_ssh_keytype} --private
 
 CRYPKI_CONFIG=`sed -e "s/SLOTNUM_USER_SSH/${user_ssh_slot}/g; s/SLOTNUM_HOST_X509/${host_x509_slot}/g; s/SLOTNUM_HOST_SSH/${host_ssh_slot}/g" crypki.conf.sample`
 

pkcs11/ecdsa.go

@@ -2,17 +2,133 @@ package pkcs11
 
 import (
 	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"encoding/asn1"
 	"errors"
+	"fmt"
+	"math/big"
 
 	p11 "github.com/miekg/pkcs11"
 )
 
+// Representation of a *DSA signature
+type dsaSignature struct {
+	R, S *big.Int
+}
+
+// oidDERToCurve maps the hex of the DER encoding of the various curve OIDs to
+// the relevant curve parameters
+var oidDERToCurve = map[string]*elliptic.CurveParams{
+	"06052B81040021":       elliptic.P224().Params(),
+	"06082A8648CE3D030107": elliptic.P256().Params(),
+	"06052B81040022":       elliptic.P384().Params(),
+	"06052B81040023":       elliptic.P521().Params(),
+}
+
+func getPublic(point []byte) (pub crypto.PublicKey, err error) {
+	var ecdsaPub ecdsa.PublicKey
+
+	ecdsaPub.Curve = elliptic.P256() // TODO: allow other curves
+	pointLength := ecdsaPub.Curve.Params().BitSize/8*2 + 1
+	if len(point) != pointLength {
+		err = fmt.Errorf("CKA_EC_POINT (%d) does not fit used curve (%d)", len(point), pointLength)
+		return
+	}
+	ecdsaPub.X, ecdsaPub.Y = elliptic.Unmarshal(ecdsaPub.Curve, point[:pointLength])
+	if ecdsaPub.X == nil {
+		err = fmt.Errorf("failed to decode CKA_EC_POINT")
+		return
+	}
+	if !ecdsaPub.Curve.IsOnCurve(ecdsaPub.X, ecdsaPub.Y) {
+		err = fmt.Errorf("public key is not on curve")
+		return
+	}
+
+	pub = &ecdsaPub
+	return
+}
+
 func publicECDSA(s *p11Signer) crypto.PublicKey {
-	// TODO: implement
-	panic("not implemented yet")
+	// Retrieve the curve and public point for the generated public key
+	attrs, err := s.context.GetAttributeValue(s.session, s.publicKey, []*p11.Attribute{
+		p11.NewAttribute(p11.CKA_EC_PARAMS, nil),
+		p11.NewAttribute(p11.CKA_EC_POINT, nil),
+	})
+	if len(attrs) < 2 {
+		panic("expected two attributes")
+	}
+
+	/*
+		// TODO: use this to make it work for other curves
+		cur, ok := oidDERToCurve[fmt.Sprintf("%X", attrs[0].Value)]
+		if !ok {
+			panic("unknown curve")
+		}
+	*/
+	pointBytes := attrs[1].Value
+	if pointBytes == nil {
+		panic("unable to get EC point")
+	}
+	var pb []byte
+	_, err = asn1.Unmarshal(pointBytes, &pb)
+	if err != nil {
+		panic("asn1 unmarshal failed: " + err.Error())
+	}
+	pubkey, err := getPublic(pb)
+	if err != nil {
+		panic("getPublic failed: " + err.Error())
+	}
+	return pubkey
 }
 
 func signDataECDSA(ctx PKCS11Ctx, session p11.SessionHandle, hsmPrivateObject p11.ObjectHandle, data []byte, opts crypto.SignerOpts) ([]byte, error) {
-	// TODO: implement
-	return nil, errors.New("not implemented yet")
+	const MAXBYTES = 262042
+	if len(data) > MAXBYTES {
+		return nil, errors.New("Cannot sign such a large blob of data")
+	}
+
+	privateKeyHandle := hsmPrivateObject
+
+	// We only support SHA1, SHA256, SHA384 and SHA512 hash digest algorithms.
+	hash := opts.HashFunc()
+	mech := make([]*p11.Mechanism, 1)
+	switch hash {
+	case crypto.SHA1, crypto.SHA256, crypto.SHA384, crypto.SHA512:
+		mech[0] = p11.NewMechanism(p11.CKM_ECDSA, nil)
+	default:
+		return nil, errors.New("Unsupported hash algorithm")
+	}
+
+	err := ctx.SignInit(session, mech, privateKeyHandle)
+	if err != nil {
+		return nil, err
+	}
+	sigBytes, err := ctx.Sign(session, data)
+	if err != nil {
+		return nil, err
+	}
+	var sig dsaSignature
+	err = sig.unmarshalBytes(sigBytes)
+	if err != nil {
+		return nil, err
+	}
+	return sig.marshalDER()
+}
+
+// Return the DER encoding of a dsaSignature
+func (sig *dsaSignature) marshalDER() ([]byte, error) {
+	return asn1.Marshal(*sig)
+}
+
+// Populate a dsaSignature from a raw byte sequence
+func (sig *dsaSignature) unmarshalBytes(sigBytes []byte) error {
+	if len(sigBytes) == 0 || len(sigBytes)%2 != 0 {
+		return errors.New("malformed signature")
+	}
+	n := len(sigBytes) / 2
+	sig.R, sig.S = new(big.Int), new(big.Int)
+	sig.R.SetBytes(sigBytes[:n])
+	sig.S.SetBytes(sigBytes[n:])
+	return nil
 }