388 lines
10 KiB
Go
388 lines
10 KiB
Go
// Package saml contains login methods for SAML.
|
|
package saml
|
|
|
|
import (
|
|
"bytes"
|
|
"compress/flate"
|
|
"crypto/rand"
|
|
"crypto/x509"
|
|
"encoding/base64"
|
|
"encoding/hex"
|
|
"encoding/pem"
|
|
"encoding/xml"
|
|
"errors"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"strings"
|
|
"time"
|
|
|
|
"github.com/Sirupsen/logrus"
|
|
"github.com/beevik/etree"
|
|
dsig "github.com/russellhaering/goxmldsig"
|
|
|
|
"github.com/coreos/dex/connector"
|
|
)
|
|
|
|
const (
|
|
bindingRedirect = "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
|
|
bindingPOST = "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
|
|
|
|
nameIDFormatEmailAddress = "urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
|
|
nameIDFormatUnspecified = "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified"
|
|
nameIDFormatX509Subject = "urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName"
|
|
nameIDFormatWindowsDN = "urn:oasis:names:tc:SAML:1.1:nameid-format:WindowsDomainQualifiedName"
|
|
nameIDFormatEncrypted = "urn:oasis:names:tc:SAML:2.0:nameid-format:encrypted"
|
|
nameIDFormatEntity = "urn:oasis:names:tc:SAML:2.0:nameid-format:entity"
|
|
nameIDFormatKerberos = "urn:oasis:names:tc:SAML:2.0:nameid-format:kerberos"
|
|
nameIDFormatPersistent = "urn:oasis:names:tc:SAML:2.0:nameid-format:persistent"
|
|
nameIDformatTransient = "urn:oasis:names:tc:SAML:2.0:nameid-format:transient"
|
|
)
|
|
|
|
var (
|
|
nameIDFormats = []string{
|
|
nameIDFormatEmailAddress,
|
|
nameIDFormatUnspecified,
|
|
nameIDFormatX509Subject,
|
|
nameIDFormatWindowsDN,
|
|
nameIDFormatEncrypted,
|
|
nameIDFormatEntity,
|
|
nameIDFormatKerberos,
|
|
nameIDFormatPersistent,
|
|
nameIDformatTransient,
|
|
}
|
|
nameIDFormatLookup = make(map[string]string)
|
|
)
|
|
|
|
func init() {
|
|
suffix := func(s, sep string) string {
|
|
if i := strings.LastIndex(s, sep); i > 0 {
|
|
return s[i+1:]
|
|
}
|
|
return s
|
|
}
|
|
for _, format := range nameIDFormats {
|
|
nameIDFormatLookup[suffix(format, ":")] = format
|
|
nameIDFormatLookup[format] = format
|
|
}
|
|
}
|
|
|
|
// Config represents configuration options for the SAML provider.
|
|
type Config struct {
|
|
// TODO(ericchiang): A bunch of these fields could be auto-filled if
|
|
// we supported SAML metadata discovery.
|
|
//
|
|
// https://www.oasis-open.org/committees/download.php/35391/sstc-saml-metadata-errata-2.0-wd-04-diff.pdf
|
|
|
|
Issuer string `json:"issuer"`
|
|
SSOURL string `json:"ssoURL"`
|
|
|
|
// X509 CA file or raw data to verify XML signatures.
|
|
CA string `json:"ca"`
|
|
CAData []byte `json:"caData"`
|
|
|
|
InsecureSkipSignatureValidation bool `json:"insecureSkipSignatureValidation"`
|
|
|
|
// Assertion attribute names to lookup various claims with.
|
|
UsernameAttr string `json:"usernameAttr"`
|
|
EmailAttr string `json:"emailAttr"`
|
|
GroupsAttr string `json:"groupsAttr"`
|
|
// If GroupsDelim is supplied the connector assumes groups are returned as a
|
|
// single string instead of multiple attribute values. This delimiter will be
|
|
// used split the groups string.
|
|
GroupsDelim string `json:"groupsDelim"`
|
|
|
|
RedirectURI string `json:"redirectURI"`
|
|
|
|
// Requested format of the NameID. The NameID value is is mapped to the ID Token
|
|
// 'sub' claim.
|
|
//
|
|
// This can be an abbreviated form of the full URI with just the last component. For
|
|
// example, if this value is set to "emailAddress" the format will resolve to:
|
|
//
|
|
// urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress
|
|
//
|
|
// If no value is specified, this value defaults to:
|
|
//
|
|
// urn:oasis:names:tc:SAML:2.0:nameid-format:persistent
|
|
//
|
|
NameIDPolicyFormat string `json:"nameIDPolicyFormat"`
|
|
}
|
|
|
|
type certStore struct {
|
|
certs []*x509.Certificate
|
|
}
|
|
|
|
func (c certStore) Certificates() (roots []*x509.Certificate, err error) {
|
|
return c.certs, nil
|
|
}
|
|
|
|
// Open validates the config and returns a connector. It does not actually
|
|
// validate connectivity with the provider.
|
|
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
|
|
return c.openConnector(logger)
|
|
}
|
|
|
|
func (c *Config) openConnector(logger logrus.FieldLogger) (interface {
|
|
connector.SAMLConnector
|
|
}, error) {
|
|
requiredFields := []struct {
|
|
name, val string
|
|
}{
|
|
{"issuer", c.Issuer},
|
|
{"ssoURL", c.SSOURL},
|
|
{"usernameAttr", c.UsernameAttr},
|
|
{"emailAttr", c.EmailAttr},
|
|
{"redirectURI", c.RedirectURI},
|
|
}
|
|
var missing []string
|
|
for _, f := range requiredFields {
|
|
if f.val == "" {
|
|
missing = append(missing, f.name)
|
|
}
|
|
}
|
|
switch len(missing) {
|
|
case 0:
|
|
case 1:
|
|
return nil, fmt.Errorf("missing required field %q", missing[0])
|
|
default:
|
|
return nil, fmt.Errorf("missing required fields %q", missing)
|
|
}
|
|
|
|
p := &provider{
|
|
issuer: c.Issuer,
|
|
ssoURL: c.SSOURL,
|
|
now: time.Now,
|
|
usernameAttr: c.UsernameAttr,
|
|
emailAttr: c.EmailAttr,
|
|
groupsAttr: c.GroupsAttr,
|
|
groupsDelim: c.GroupsDelim,
|
|
redirectURI: c.RedirectURI,
|
|
logger: logger,
|
|
|
|
nameIDPolicyFormat: c.NameIDPolicyFormat,
|
|
}
|
|
|
|
if p.nameIDPolicyFormat == "" {
|
|
p.nameIDPolicyFormat = nameIDFormatPersistent
|
|
} else {
|
|
if format, ok := nameIDFormatLookup[p.nameIDPolicyFormat]; ok {
|
|
p.nameIDPolicyFormat = format
|
|
} else {
|
|
return nil, fmt.Errorf("invalid nameIDPolicyFormat: %q", p.nameIDPolicyFormat)
|
|
}
|
|
}
|
|
|
|
if !c.InsecureSkipSignatureValidation {
|
|
if (c.CA == "") == (c.CAData == nil) {
|
|
return nil, errors.New("must provide either 'ca' or 'caData'")
|
|
}
|
|
|
|
var caData []byte
|
|
if c.CA != "" {
|
|
data, err := ioutil.ReadFile(c.CA)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("read ca file: %v", err)
|
|
}
|
|
caData = data
|
|
} else {
|
|
caData = c.CAData
|
|
}
|
|
|
|
var (
|
|
certs []*x509.Certificate
|
|
block *pem.Block
|
|
)
|
|
for {
|
|
block, caData = pem.Decode(caData)
|
|
if block == nil {
|
|
break
|
|
}
|
|
cert, err := x509.ParseCertificate(block.Bytes)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("parse cert: %v", err)
|
|
}
|
|
certs = append(certs, cert)
|
|
}
|
|
if len(certs) == 0 {
|
|
return nil, errors.New("no certificates found in ca data")
|
|
}
|
|
p.validator = dsig.NewDefaultValidationContext(certStore{certs})
|
|
}
|
|
return p, nil
|
|
}
|
|
|
|
type provider struct {
|
|
issuer string
|
|
ssoURL string
|
|
|
|
now func() time.Time
|
|
|
|
// If nil, don't do signature validation.
|
|
validator *dsig.ValidationContext
|
|
|
|
// Attribute mappings
|
|
usernameAttr string
|
|
emailAttr string
|
|
groupsAttr string
|
|
groupsDelim string
|
|
|
|
redirectURI string
|
|
|
|
nameIDPolicyFormat string
|
|
|
|
logger logrus.FieldLogger
|
|
}
|
|
|
|
func (p *provider) POSTData(s connector.Scopes) (action, value string, err error) {
|
|
|
|
// NOTE(ericchiang): If we can't follow up with the identity provider, can we
|
|
// support refresh tokens?
|
|
if s.OfflineAccess {
|
|
return "", "", fmt.Errorf("SAML does not support offline access")
|
|
}
|
|
|
|
r := &authnRequest{
|
|
ProtocolBinding: bindingPOST,
|
|
ID: "_" + uuidv4(),
|
|
IssueInstant: xmlTime(p.now()),
|
|
Destination: p.ssoURL,
|
|
Issuer: &issuer{
|
|
Issuer: p.issuer,
|
|
},
|
|
NameIDPolicy: &nameIDPolicy{
|
|
AllowCreate: true,
|
|
Format: p.nameIDPolicyFormat,
|
|
},
|
|
}
|
|
|
|
data, err := xml.MarshalIndent(r, "", " ")
|
|
if err != nil {
|
|
return "", "", fmt.Errorf("marshal authn request: %v", err)
|
|
}
|
|
|
|
buff := new(bytes.Buffer)
|
|
fw, err := flate.NewWriter(buff, flate.DefaultCompression)
|
|
if err != nil {
|
|
return "", "", fmt.Errorf("new flate writer: %v", err)
|
|
}
|
|
if _, err := fw.Write(data); err != nil {
|
|
return "", "", fmt.Errorf("compress message: %v", err)
|
|
}
|
|
if err := fw.Close(); err != nil {
|
|
return "", "", fmt.Errorf("flush message: %v", err)
|
|
}
|
|
|
|
return p.ssoURL, base64.StdEncoding.EncodeToString(buff.Bytes()), nil
|
|
}
|
|
|
|
func (p *provider) HandlePOST(s connector.Scopes, samlResponse string) (ident connector.Identity, err error) {
|
|
rawResp, err := base64.StdEncoding.DecodeString(samlResponse)
|
|
if err != nil {
|
|
return ident, fmt.Errorf("decode response: %v", err)
|
|
}
|
|
if p.validator != nil {
|
|
if rawResp, err = verify(p.validator, rawResp); err != nil {
|
|
return ident, fmt.Errorf("verify signature: %v", err)
|
|
}
|
|
}
|
|
|
|
var resp response
|
|
if err := xml.Unmarshal(rawResp, &resp); err != nil {
|
|
return ident, fmt.Errorf("unmarshal response: %v", err)
|
|
}
|
|
|
|
if resp.Destination != "" && resp.Destination != p.redirectURI {
|
|
return ident, fmt.Errorf("expected destination %q got %q", p.redirectURI, resp.Destination)
|
|
|
|
}
|
|
|
|
assertion := resp.Assertion
|
|
if assertion == nil {
|
|
return ident, fmt.Errorf("response did not contain an assertion")
|
|
}
|
|
subject := assertion.Subject
|
|
if subject == nil {
|
|
return ident, fmt.Errorf("response did not contain a subject")
|
|
}
|
|
|
|
switch {
|
|
case subject.NameID != nil:
|
|
if ident.UserID = subject.NameID.Value; ident.UserID == "" {
|
|
return ident, fmt.Errorf("NameID element does not contain a value")
|
|
}
|
|
default:
|
|
return ident, fmt.Errorf("subject does not contain an NameID element")
|
|
}
|
|
|
|
attributes := assertion.AttributeStatement
|
|
if attributes == nil {
|
|
return ident, fmt.Errorf("response did not contain a AttributeStatement")
|
|
}
|
|
|
|
if ident.Email, _ = attributes.get(p.emailAttr); ident.Email == "" {
|
|
return ident, fmt.Errorf("no attribute with name %q", p.emailAttr)
|
|
}
|
|
ident.EmailVerified = true
|
|
|
|
if ident.Username, _ = attributes.get(p.usernameAttr); ident.Username == "" {
|
|
return ident, fmt.Errorf("no attribute with name %q", p.usernameAttr)
|
|
}
|
|
|
|
if s.Groups && p.groupsAttr != "" {
|
|
if p.groupsDelim != "" {
|
|
groupsStr, ok := attributes.get(p.groupsAttr)
|
|
if !ok {
|
|
return ident, fmt.Errorf("no attribute with name %q", p.groupsAttr)
|
|
}
|
|
// TOOD(ericchiang): Do we need to further trim whitespace?
|
|
ident.Groups = strings.Split(groupsStr, p.groupsDelim)
|
|
} else {
|
|
groups, ok := attributes.all(p.groupsAttr)
|
|
if !ok {
|
|
return ident, fmt.Errorf("no attribute with name %q", p.groupsAttr)
|
|
}
|
|
ident.Groups = groups
|
|
}
|
|
}
|
|
|
|
return ident, nil
|
|
}
|
|
|
|
// verify checks the signature info of a XML document and returns
|
|
// the signed elements.
|
|
func verify(validator *dsig.ValidationContext, data []byte) (signed []byte, err error) {
|
|
doc := etree.NewDocument()
|
|
if err := doc.ReadFromBytes(data); err != nil {
|
|
return nil, fmt.Errorf("parse document: %v", err)
|
|
}
|
|
|
|
result, err := validator.Validate(doc.Root())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
doc.SetRoot(result)
|
|
return doc.WriteToBytes()
|
|
}
|
|
|
|
func uuidv4() string {
|
|
u := make([]byte, 16)
|
|
if _, err := rand.Read(u); err != nil {
|
|
panic(err)
|
|
}
|
|
u[6] = (u[6] | 0x40) & 0x4F
|
|
u[8] = (u[8] | 0x80) & 0xBF
|
|
|
|
r := make([]byte, 36)
|
|
r[8] = '-'
|
|
r[13] = '-'
|
|
r[18] = '-'
|
|
r[23] = '-'
|
|
hex.Encode(r, u[0:4])
|
|
hex.Encode(r[9:], u[4:6])
|
|
hex.Encode(r[14:], u[6:8])
|
|
hex.Encode(r[19:], u[8:10])
|
|
hex.Encode(r[24:], u[10:])
|
|
|
|
return string(r)
|
|
}
|