19 files changed, 306 insertions, 4 deletions
diff --git a/README.md b/README.md
index a80deef0..4fa7eded 100644
--- a/README.md
+++ b/README.md
@@ -172,6 +172,16 @@ There are some configs you need to change in the files below
 | HMD_LDAP_SEARCHATTRIBUTES | no example | LDAP attributes to search with |
 | HMD_LDAP_TLS_CA | `server-cert.pem, root.pem` | Root CA for LDAP TLS in PEM format (use comma to separate) |
 | HMD_LDAP_PROVIDERNAME | `My institution` | Optional name to be displayed at login form indicating the LDAP provider |
+| HMD_SAML_IDPSSOURL | `https://idp.example.com/sso` | authentication endpoint of IdP. for details, see [guide](docs/guides/auth.md#saml-onelogin). |
+| HMD_SAML_IDPCERT | `/path/to/cert.pem` | certificate file path of IdP in PEM format |
+| HMD_SAML_ISSUER | no example | identity of the service provider (optional, default: serverurl)" |
+| HMD_SAML_IDENTIFIERFORMAT | no example | name identifier format (optional, default: `urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress`) |
+| HMD_SAML_GROUPATTRIBUTE | `memberOf` | attribute name for group list (optional) |
+| HMD_SAML_REQUIREDGROUPS | `Hackmd-users` | group names that allowed (use vertical bar to separate) (optional) |
+| HMD_SAML_EXTERNALGROUPS | `Temporary-staff` | group names that not allowed (use vertical bar to separate) (optional) |
+| HMD_SAML_ATTRIBUTE_ID | `sAMAccountName` | attribute map for `id` (optional, default: NameID of SAML response) |
+| HMD_SAML_ATTRIBUTE_USERNAME | `mailNickname` | attribute map for `username` (optional, default: NameID of SAML response) |
+| HMD_SAML_ATTRIBUTE_EMAIL | `mail` | attribute map for `email` (optional, default: NameID of SAML response if `HMD_SAML_IDENTIFIERFORMAT` is default) |
 | HMD_IMGUR_CLIENTID | no example | Imgur API client id |
 | HMD_EMAIL | `true` or `false` | set to allow email signin |
 | HMD_ALLOW_PDF_EXPORT | `true` or `false` | Enable or disable PDF exports |
@@ -234,7 +244,7 @@ There are some configs you need to change in the files below
 
 | service | settings location | description |
 | ------- | --------- | ----------- |
-| facebook, twitter, github, gitlab, mattermost, dropbox, google, ldap | environment variables or `config.json` | for signin |
+| facebook, twitter, github, gitlab, mattermost, dropbox, google, ldap, saml | environment variables or `config.json` | for signin |
 | imgur, s3 | environment variables or `config.json` | for image upload |
 | google drive(`google/apiKey`, `google/clientID`), dropbox(`dropbox/appKey`) | `config.json` | for export and import |
 
@@ -249,6 +259,7 @@ There are some configs you need to change in the files below
 | mattermost | `/auth/mattermost/callback` |
 | dropbox | `/auth/dropbox/callback` |
 | google | `/auth/google/callback` |
+| saml | `/auth/saml/callback` |
 
 # Developer Notes
 
diff --git a/config.json.example b/config.json.example
index bd7ab043..8d23be8a 100644
--- a/config.json.example
+++ b/config.json.example
@@ -75,6 +75,20 @@
                 "changeme": "See https://nodejs.org/api/tls.html#tls_tls_connect_options_callback"
             }
         },
+        "saml": {
+            "idpSsoUrl": "change: authentication endpoint of IdP",
+            "idpCert": "change: certificate file path of IdP in PEM format",
+            "issuer": "change or delete: identity of the service provider (default: serverurl)",
+            "identifierFormat": "change or delete: name identifier format (default: 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress')",
+            "groupAttribute": "change or delete: attribute name for group list (ex: memberOf)",
+            "requiredGroups": [ "change or delete: group names that allowed" ],
+            "externalGroups": [ "change or delete: group names that not allowed" ],
+            "attribute": {
+               "id": "change or delete this: attribute map for `id` (default: NameID)",
+               "username": "change or delete this: attribute map for `username` (default: NameID)",
+               "email": "change or delete this: attribute map for `email` (default: NameID)"
+            }
+        },
         "imgur": {
             "clientID": "change this"
         },
diff --git a/docs/guides/auth.md b/docs/guides/auth.md
index 37b89004..4f9ce445 100644
--- a/docs/guides/auth.md
+++ b/docs/guides/auth.md
@@ -75,3 +75,138 @@ To do this Click your profile icon --> Settings and privacy --> Mobile  --> Sele
       HMD_GITHUB_CLIENTID=3747d30eaccXXXXXXXXX
       HMD_GITHUB_CLIENTSECRET=2a8e682948eee0c580XXXXXXXXXXXXXXXXXXXXXX
       ````
+
+### SAML (OneLogin)
+1. Sign-in or sign-up for an OneLogin account. (available free trial for 2 weeks)
+2. Go to the administration page.
+3. Select the **APPS** menu and click on the **Add Apps**.
+
+![onelogin-add-app](images/auth/onelogin-add-app.png)
+
+4. Find "SAML Test Connector (SP)" for template of settings and select it.
+
+![onelogin-select-template](images/auth/onelogin-select-template.png)
+
+5. Edit display name and icons for OneLogin dashboard as you want, and click **SAVE**.
+
+![onelogin-edit-app-name](images/auth/onelogin-edit-app-name.png)
+
+6. After that other tabs will appear, click the **Configuration**, and fill out the below items, and click **SAVE**.
+    * RelayState: The base URL of your hackmd, which is issuer. (last slash is not needed)
+    * ACS (Consumer) URL Validator: The callback URL of your hackmd. (serverurl + /auth/saml/callback)
+    * ACS (Consumer) URL: same as above.
+    * Login URL: login URL(SAML requester) of your hackmd. (serverurl + /auth/saml)
+
+![onelogin-edit-sp-metadata](images/auth/onelogin-edit-sp-metadata.png)
+
+7. The registration is completed. Next, click **SSO** and copy or download the items below.
+    * X.509 Certificate: Click **View Details** and **DOWNLOAD** or copy the content of certificate ....(A)
+    * SAML 2.0 Endpoint (HTTP): Copy the URL ....(B)
+
+![onelogin-copy-idp-metadata](images/auth/onelogin-copy-idp-metadata.png)
+
+8. In your hackmd server, create IdP certificate file from (A)
+9. Add the IdP URL (B) and the Idp certificate file path to your config.json file or pass them as environment variables.
+    * config.json:
+      ````javascript
+      {
+        "production": {
+          "saml": {
+            "idpSsoUrl": "https://*******.onelogin.com/trust/saml2/http-post/sso/******",
+            "idpCert": "/path/to/idp_cert.pem"
+          }
+        }
+      }
+      ````
+    * environment variables
+      ````
+      HMD_SAML_IDPSSOURL=https://*******.onelogin.com/trust/saml2/http-post/sso/******
+      HMD_SAML_IDPCERT=/path/to/idp_cert.pem
+      ````
+10. Try sign-in with SAML from your hackmd sign-in button or OneLogin dashboard (like the screenshot below). 
+
+![onelogin-use-dashboard](images/auth/onelogin-use-dashboard.png)
+
+### SAML (Other cases)
+The basic procedure is the same as the case of OneLogin which is mentioned above. If you want to match your IdP, you can use more configurations as below.
+
+* If your IdP accepts metadata XML of the service provider to ease configuraion, use this url to download metadata XML.
+    * {{your-serverurl}}/auth/saml/metadata
+    * _Note: If not accessable from IdP, download to local once and upload to IdP._
+* Change the value of `issuer`, `identifierFormat` to match your IdP.
+  * `issuer`: A unique id to identify the application to the IdP, which is the base URL of your HackMD as default
+  * `identifierFormat`: A format of unique id to identify the user of IdP, which is the format based on email address as default. It is recommend that you use as below.
+    * urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress (default)
+    * urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified
+  * config.json:
+    ````javascript
+    {
+      "production": {
+        "saml": {
+          /* omitted */
+          "issuer": "myhackmd"
+          "identifierFormat": "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified"
+        }
+      }
+    }
+    ````
+  * environment variables
+    ````
+    HMD_SAML_ISSUER=myhackmd
+    HMD_SAML_IDENTIFIERFORMAT=urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified
+    ````
+
+* Change mapping of attribute names to customize the displaying user name and email address to match your IdP.
+  * `attribute`: A dictionary to map attribute names
+  * `attribute.id`: A primary key of user table for your HackMD
+  * `attribute.username`: Attribute name of displaying user name on HackMD
+  * `attribute.email`: Attribute name of email address, which will be also used for Gravatar
+    * _Note: Default value of all attributes is NameID of SAML response, which is email address if `idfentifierFormat` is default._
+  * config.json:
+    ````javascript
+    {
+      "production": {
+        "saml": {
+          /* omitted */
+          "attribute": {
+            "id": "sAMAccountName",
+            "username": "displayName",
+            "email": "mail"
+          }
+        }
+      }
+    }
+    ````
+  * environment variables
+    ````
+    HMD_SAML_ATTRIBUTE_ID=sAMAccountName
+    HMD_SAML_ATTRIBUTE_USERNAME=nickName
+    HMD_SAML_ATTRIBUTE_EMAIL=mail
+    ````
+
+* If you want to controll permission by group membership, add group attribute name and required group (allowed) or external group (not allowed).
+  * `groupAttribute`: An attribute name of group membership
+  * `requiredGroups`: Group names array for allowed access to HackMD. Use vertical bar to separate for environment variables.
+  * `externalGroups`: Group names array for not allowed access to HackMD. Use vertical bar to separate for environment variables.
+    * _Note: Evaluates `externalGroups` first_
+  * config.json:
+    ````javascript
+    {
+      "production": {
+        "saml": {
+          /* omitted */
+          "groupAttribute": "memberOf",
+          "requiredGroups": [ "hackmd-users", "board-members" ],
+          "externalGroups": [ "temporary-staff" ]
+        }
+      }
+    }
+    ````
+  * environment variables
+    ````
+    HMD_SAML_GROUPATTRIBUTE=memberOf
+    HMD_SAML_REQUIREDGROUPS=hackmd-users|board-members
+    HMD_SAML_EXTERNALGROUPS=temporary-staff
+    ````
+
+
diff --git a/docs/guides/images/auth/onelogin-add-app.png b/docs/guides/images/auth/onelogin-add-app.png
new file mode 100644
index 00000000..356bb852
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-add-app.png
diff --git a/docs/guides/images/auth/onelogin-copy-idp-metadata.png b/docs/guides/images/auth/onelogin-copy-idp-metadata.png
new file mode 100644
index 00000000..7185f537
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-copy-idp-metadata.png
diff --git a/docs/guides/images/auth/onelogin-edit-app-name.png b/docs/guides/images/auth/onelogin-edit-app-name.png
new file mode 100644
index 00000000..634d1916
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-edit-app-name.png
diff --git a/docs/guides/images/auth/onelogin-edit-sp-metadata.png b/docs/guides/images/auth/onelogin-edit-sp-metadata.png
new file mode 100644
index 00000000..111580b1
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-edit-sp-metadata.png
diff --git a/docs/guides/images/auth/onelogin-select-template.png b/docs/guides/images/auth/onelogin-select-template.png
new file mode 100644
index 00000000..13401816
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-select-template.png
diff --git a/docs/guides/images/auth/onelogin-use-dashboard.png b/docs/guides/images/auth/onelogin-use-dashboard.png
new file mode 100644
index 00000000..ea9038ff
--- /dev/null
+++ b/docs/guides/images/auth/onelogin-use-dashboard.png
diff --git a/lib/config/default.js b/lib/config/default.js
index 273bad02..d04485ce 100644
--- a/lib/config/default.js
+++ b/lib/config/default.js
@@ -98,6 +98,20 @@ module.exports = {
     searchAttributes: undefined,
     tlsca: undefined
   },
+  saml: {
+    idpSsoUrl: undefined,
+    idpCert: undefined,
+    issuer: undefined,
+    identifierFormat: 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress',
+    groupAttribute: undefined,
+    externalGroups: [],
+    requiredGroups: [],
+    attribute: {
+      id: undefined,
+      username: undefined,
+      email: undefined
+    }
+  },
   email: true,
   allowemailregister: true,
   allowpdfexport: true
diff --git a/lib/config/environment.js b/lib/config/environment.js
index 0c272f05..b7b0e3f8 100644
--- a/lib/config/environment.js
+++ b/lib/config/environment.js
@@ -73,6 +73,20 @@ module.exports = {
     searchAttributes: process.env.HMD_LDAP_SEARCHATTRIBUTES,
     tlsca: process.env.HMD_LDAP_TLS_CA
   },
+  saml: {
+    idpSsoUrl: process.env.HMD_SAML_IDPSSOURL,
+    idpCert: process.env.HMD_SAML_IDPCERT,
+    issuer: process.env.HMD_SAML_ISSUER,
+    identifierFormat: process.env.HMD_SAML_IDENTIFIERFORMAT,
+    groupAttribute: process.env.HMD_SAML_GROUPATTRIBUTE,
+    externalGroups: process.env.HMD_SAML_EXTERNALGROUPS ? process.env.HMD_SAML_EXTERNALGROUPS.split('|') : [],
+    requiredGroups: process.env.HMD_SAML_REQUIREDGROUPS ? process.env.HMD_SAML_REQUIREDGROUPS.split('|') : [],
+    attribute: {
+      id: process.env.HMD_SAML_ATTRIBUTE_ID,
+      username: process.env.HMD_SAML_ATTRIBUTE_USERNAME,
+      email: process.env.HMD_SAML_ATTRIBUTE_EMAIL
+    }
+  },
   email: toBooleanConfig(process.env.HMD_EMAIL),
   allowemailregister: toBooleanConfig(process.env.HMD_ALLOW_EMAIL_REGISTER),
   allowpdfexport: toBooleanConfig(process.env.HMD_ALLOW_PDF_EXPORT)
diff --git a/lib/config/index.js b/lib/config/index.js
index addd8ba6..3ac3de53 100644
--- a/lib/config/index.js
+++ b/lib/config/index.js
@@ -92,6 +92,7 @@ config.isGitHubEnable = config.github.clientID && config.github.clientSecret
 config.isGitLabEnable = config.gitlab.clientID && config.gitlab.clientSecret
 config.isMattermostEnable = config.mattermost.clientID && config.mattermost.clientSecret
 config.isLDAPEnable = config.ldap.url
+config.isSAMLEnable = config.saml.idpSsoUrl
 config.isPDFExportEnable = config.allowpdfexport
 
 // generate correct path
diff --git a/lib/models/user.js b/lib/models/user.js
index 27566def..f421fe43 100644
--- a/lib/models/user.js
+++ b/lib/models/user.js
@@ -143,6 +143,15 @@ module.exports = function (sequelize, DataTypes) {
               photo = letterAvatars(profile.username)
             }
             break
+          case 'saml':
+            if (profile.emails[0]) {
+              photo = 'https://www.gravatar.com/avatar/' + md5(profile.emails[0])
+              if (bigger) photo += '?s=400'
+              else photo += '?s=96'
+            } else {
+              photo = letterAvatars(profile.username)
+            }
+            break
         }
         return photo
       },
diff --git a/lib/response.js b/lib/response.js
index 61ce5747..9f3d5a44 100755
--- a/lib/response.js
+++ b/lib/response.js
@@ -68,6 +68,7 @@ function showIndex (req, res, next) {
     dropbox: config.isDropboxEnable,
     google: config.isGoogleEnable,
     ldap: config.isLDAPEnable,
+    saml: config.isSAMLEnable,
     email: config.isEmailEnable,
     allowemailregister: config.allowemailregister,
     allowpdfexport: config.allowpdfexport,
@@ -100,6 +101,7 @@ function responseHackMD (res, note) {
     dropbox: config.isDropboxEnable,
     google: config.isGoogleEnable,
     ldap: config.isLDAPEnable,
+    saml: config.isSAMLEnable,
     email: config.isEmailEnable,
     allowemailregister: config.allowemailregister,
     allowpdfexport: config.allowpdfexport
diff --git a/lib/web/auth/index.js b/lib/web/auth/index.js
index 4b618101..db5ff11d 100644
--- a/lib/web/auth/index.js
+++ b/lib/web/auth/index.js
@@ -37,6 +37,7 @@ if (config.isMattermostEnable) authRouter.use(require('./mattermost'))
 if (config.isDropboxEnable) authRouter.use(require('./dropbox'))
 if (config.isGoogleEnable) authRouter.use(require('./google'))
 if (config.isLDAPEnable) authRouter.use(require('./ldap'))
+if (config.isSAMLEnable) authRouter.use(require('./saml'))
 if (config.isEmailEnable) authRouter.use(require('./email'))
 
 // logout
diff --git a/lib/web/auth/saml/index.js b/lib/web/auth/saml/index.js
new file mode 100644
index 00000000..386293ae
--- /dev/null
+++ b/lib/web/auth/saml/index.js
@@ -0,0 +1,95 @@
+'use strict'
+
+const Router = require('express').Router
+const passport = require('passport')
+const SamlStrategy = require('passport-saml').Strategy
+const config = require('../../../config')
+const models = require('../../../models')
+const logger = require('../../../logger')
+const {urlencodedParser} = require('../../utils')
+const fs = require('fs')
+const intersection = function (array1, array2) { return array1.filter((n) => array2.includes(n)) }
+
+let samlAuth = module.exports = Router()
+
+passport.use(new SamlStrategy({
+  callbackUrl: config.serverurl + '/auth/saml/callback',
+  entryPoint: config.saml.idpSsoUrl,
+  issuer: config.saml.issuer || config.serverurl,
+  cert: fs.readFileSync(config.saml.idpCert, 'utf-8'),
+  identifierFormat: config.saml.identifierFormat
+}, function (user, done) {
+  // check authorization if needed
+  if (config.saml.externalGroups && config.saml.grouptAttribute) {
+    var externalGroups = intersection(config.saml.externalGroups, user[config.saml.groupAttribute])
+    if (externalGroups.length > 0) {
+      logger.error('saml permission denied: ' + externalGroups.join(', '))
+      return done('Permission denied', null)
+    }
+  }
+  if (config.saml.requiredGroups && config.saml.grouptAttribute) {
+    if (intersection(config.saml.requiredGroups, user[config.saml.groupAttribute]).length === 0) {
+      logger.error('saml permission denied')
+      return done('Permission denied', null)
+    }
+  }
+  // user creation
+  var uuid = user[config.saml.attribute.id] || user.nameID
+  var profile = {
+    provider: 'saml',
+    id: 'SAML-' + uuid,
+    username: user[config.saml.attribute.username] || user.nameID,
+    emails: user[config.saml.attribute.email] ? [user[config.saml.attribute.email]] : []
+  }
+  if (profile.emails.length === 0 && config.saml.identifierFormat === 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress') {
+    profile.emails.push(user.nameID)
+  }
+  var stringifiedProfile = JSON.stringify(profile)
+  models.User.findOrCreate({
+    where: {
+      profileid: profile.id.toString()
+    },
+    defaults: {
+      profile: stringifiedProfile
+    }
+  }).spread(function (user, created) {
+    if (user) {
+      var needSave = false
+      if (user.profile !== stringifiedProfile) {
+        user.profile = stringifiedProfile
+        needSave = true
+      }
+      if (needSave) {
+        user.save().then(function () {
+          if (config.debug) { logger.debug('user login: ' + user.id) }
+          return done(null, user)
+        })
+      } else {
+        if (config.debug) { logger.debug('user login: ' + user.id) }
+        return done(null, user)
+      }
+    }
+  }).catch(function (err) {
+    logger.error('saml auth failed: ' + err)
+    return done(err, null)
+  })
+}))
+
+samlAuth.get('/auth/saml',
+  passport.authenticate('saml', {
+    successReturnToOrRedirect: config.serverurl + '/',
+    failureRedirect: config.serverurl + '/'
+  })
+)
+
+samlAuth.post('/auth/saml/callback', urlencodedParser,
+  passport.authenticate('saml', {
+    successReturnToOrRedirect: config.serverurl + '/',
+    failureRedirect: config.serverurl + '/'
+  })
+)
+
+samlAuth.get('/auth/saml/metadata', function (req, res) {
+  res.type('application/xml')
+  res.send(passport._strategy('saml').generateServiceProviderMetadata())
+})
diff --git a/package.json b/package.json
index b4942c5a..f87a0f5c 100644
--- a/package.json
+++ b/package.json
@@ -94,6 +94,7 @@
     "passport-local": "^1.0.0",
     "passport-oauth2": "^1.4.0",
     "passport-twitter": "^1.0.4",
+    "passport-saml": "^0.31.0",
     "passport.socketio": "^3.7.0",
     "pdfobject": "^2.0.201604172",
     "pg": "^6.1.2",
diff --git a/public/views/index/body.ejs b/public/views/index/body.ejs
index 230eb117..d7b4458e 100644
--- a/public/views/index/body.ejs
+++ b/public/views/index/body.ejs
@@ -15,7 +15,7 @@
                                 <% if(allowAnonymous) { %>
                                 <a type="button" href="<%- url %>/new" class="btn btn-sm btn-primary"><i class="fa fa-plus"></i> <%= __('New guest note') %></a>
                                 <% } %>
-                                <% if(facebook || twitter || github || gitlab || mattermost || dropbox || google || ldap || email) { %>
+                                <% if(facebook || twitter || github || gitlab || mattermost || dropbox || google || ldap || saml || email) { %>
                                 <button class="btn btn-sm btn-success ui-signin" data-toggle="modal" data-target=".signin-modal"><%= __('Sign In') %></button>
                                 <% } %>
                             </div>
@@ -48,7 +48,7 @@
                     <% if (errorMessage && errorMessage.length > 0) { %>
                     <div class="alert alert-danger" style="max-width: 400px; margin: 0 auto;"><%= errorMessage %></div>
                     <% } %>
-                    <% if(facebook || twitter || github || gitlab || mattermost || dropbox || google || ldap || email) { %>
+                    <% if(facebook || twitter || github || gitlab || mattermost || dropbox || google || ldap || saml || email) { %>
                     <span class="ui-signin">
                         <br>
                         <a type="button" class="btn btn-lg btn-success ui-signin" data-toggle="modal" data-target=".signin-modal" style="min-width: 200px;"><%= __('Sign In') %></a>
diff --git a/public/views/shared/signin-modal.ejs b/public/views/shared/signin-modal.ejs
index 89b542e9..7b44cfb0 100644
--- a/public/views/shared/signin-modal.ejs
+++ b/public/views/shared/signin-modal.ejs
@@ -43,7 +43,12 @@
                     <i class="fa fa-google"></i> <%= __('Sign in via %s', 'Google') %>
                 </a>
                 <% } %>
-                <% if((facebook || twitter || github || gitlab || mattermost || dropbox || google) && ldap) { %>
+                <% if(saml) { %>
+                <a href="<%- url %>/auth/saml" class="btn btn-lg btn-block btn-social btn-success">
+                    <i class="fa fa-users"></i> <%= __('Sign in via %s', 'SAML') %>
+                </a>
+                <% } %>
+                <% if((facebook || twitter || github || gitlab || mattermost || dropbox || google || saml) && ldap) { %>
                 <hr>
                 <% }%>
                 <% if(ldap) { %>