Merge branch 'lfs-support-for-ssh-enabled' into 'master'

LFS support for ssh enabled

## What does this MR do?
This is follow-up after https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6043 which is falsely shown as merged due to: https://gitlab.com/gitlab-org/gitlab-ce/issues/22334

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6413

13 files changed, 250 insertions, 8 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 7a19af6b765..ebc3507901c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -113,6 +113,7 @@ v 8.12.0 (unreleased)
   - Remove green outline from `New branch unavailable` button on issue page !5858 (winniehell)
   - Fix repo title alignment (ClemMakesApps)
   - Change update interval of contacted_at
+  - Add LFS support to SSH !6043
   - Fix branch title trailing space on hover (ClemMakesApps)
   - Don't include 'Created By' tag line when importing from GitHub if there is a linked GitLab account (EspadaV8)
   - Award emoji tooltips containing more than 10 usernames are now truncated !4780 (jlogandavison)
diff --git a/app/controllers/projects/git_http_client_controller.rb b/app/controllers/projects/git_http_client_controller.rb
index d1a2c52d80a..cbfd3cab3dd 100644
--- a/app/controllers/projects/git_http_client_controller.rb
+++ b/app/controllers/projects/git_http_client_controller.rb
@@ -127,9 +127,11 @@ class Projects::GitHttpClientController < Projects::ApplicationController
   end
 
   def ci?
-    authentication_result.ci? &&
-      authentication_project &&
-      authentication_project == project
+    authentication_result.ci?(project)
+  end
+
+  def lfs_deploy_token?
+    authentication_result.lfs_deploy_token?(project)
   end
 
   def authentication_has_download_access?
diff --git a/app/helpers/lfs_helper.rb b/app/helpers/lfs_helper.rb
index 8e827664681..c15ecc8f86e 100644
--- a/app/helpers/lfs_helper.rb
+++ b/app/helpers/lfs_helper.rb
@@ -25,7 +25,7 @@ module LfsHelper
   def lfs_download_access?
     return false unless project.lfs_enabled?
 
-    project.public? || ci? || user_can_download_code? || build_can_download_code?
+    project.public? || ci? || lfs_deploy_token? || user_can_download_code? || build_can_download_code?
   end
 
   def user_can_download_code?
diff --git a/doc/workflow/lfs/lfs_administration.md b/doc/workflow/lfs/lfs_administration.md
index 9dc1e9b47e3..b3c73e947f0 100644
--- a/doc/workflow/lfs/lfs_administration.md
+++ b/doc/workflow/lfs/lfs_administration.md
@@ -45,5 +45,5 @@ In `config/gitlab.yml`:
 * Currently, storing GitLab Git LFS objects on a non-local storage (like S3 buckets)
   is not supported
 * Currently, removing LFS objects from GitLab Git LFS storage is not supported
-* LFS authentications via SSH is not supported for the time being
-* Only compatible with the GitLFS client versions 1.1.0 or 1.0.2.
+* LFS authentications via SSH was added with GitLab 8.12
+* Only compatible with the GitLFS client versions 1.1.0 and up, or 1.0.2.
diff --git a/doc/workflow/lfs/manage_large_binaries_with_git_lfs.md b/doc/workflow/lfs/manage_large_binaries_with_git_lfs.md
index 9fe065fa680..1a4f213a792 100644
--- a/doc/workflow/lfs/manage_large_binaries_with_git_lfs.md
+++ b/doc/workflow/lfs/manage_large_binaries_with_git_lfs.md
@@ -35,6 +35,10 @@ Documentation for GitLab instance administrators is under [LFS administration do
   credentials store is recommended
 * Git LFS always assumes HTTPS so if you have GitLab server on HTTP you will have
   to add the URL to Git config manually (see #troubleshooting)
+  
+>**Note**: With 8.12 GitLab added LFS support to SSH. The Git LFS communication
+ still goes over HTTP, but now the SSH client passes the correct credentials
+ to the Git LFS client, so no action is required by the user.
 
 ## Using Git LFS
 
@@ -132,6 +136,10 @@ git config --add lfs.url "http://gitlab.example.com/group/project.git/info/lfs"
 
 ### Credentials are always required when pushing an object
 
+>**Note**: With 8.12 GitLab added LFS support to SSH. The Git LFS communication
+ still goes over HTTP, but now the SSH client passes the correct credentials
+ to the Git LFS client, so no action is required by the user.
+
 Given that Git LFS uses HTTP Basic Authentication to authenticate the user pushing
 the LFS object on every push for every object, user HTTPS credentials are required.
 
diff --git a/lib/api/internal.rb b/lib/api/internal.rb
index 1114fd21784..090d04544da 100644
--- a/lib/api/internal.rb
+++ b/lib/api/internal.rb
@@ -82,6 +82,19 @@ module API
         response
       end
 
+      post "/lfs_authenticate" do
+        status 200
+
+        key = Key.find(params[:key_id])
+        token_handler = Gitlab::LfsToken.new(key)
+
+        {
+          username: token_handler.actor_name,
+          lfs_token: token_handler.generate,
+          repository_http_path: project.http_url_to_repo
+        }
+      end
+
       get "/merge_request_urls" do
         ::MergeRequests::GetUrlsService.new(project).execute(params[:changes])
       end
diff --git a/lib/gitlab/auth.rb b/lib/gitlab/auth.rb
index 0a0f1c3b17b..7c0f2115d43 100644
--- a/lib/gitlab/auth.rb
+++ b/lib/gitlab/auth.rb
@@ -11,6 +11,7 @@ module Gitlab
           build_access_token_check(login, password) ||
           user_with_password_for_git(login, password) ||
           oauth_access_token_check(login, password) ||
+          lfs_token_check(login, password) ||
           personal_access_token_check(login, password) ||
           Gitlab::Auth::Result.new
 
@@ -102,6 +103,30 @@ module Gitlab
         end
       end
 
+      def lfs_token_check(login, password)
+        deploy_key_matches = login.match(/\Alfs\+deploy-key-(\d+)\z/)
+
+        actor =
+          if deploy_key_matches
+            DeployKey.find(deploy_key_matches[1])
+          else
+            User.by_login(login)
+          end
+
+        return unless actor
+
+        token_handler = Gitlab::LfsToken.new(actor)
+
+        authentication_abilities =
+          if token_handler.user?
+            full_authentication_abilities
+          else
+            read_authentication_abilities
+          end
+
+        Result.new(actor, nil, token_handler.type, authentication_abilities) if Devise.secure_compare(token_handler.value, password)
+      end
+
       def build_access_token_check(login, password)
         return unless login == 'gitlab-ci-token'
         return unless password
diff --git a/lib/gitlab/auth/result.rb b/lib/gitlab/auth/result.rb
index bf625649cbf..6be7f690676 100644
--- a/lib/gitlab/auth/result.rb
+++ b/lib/gitlab/auth/result.rb
@@ -1,8 +1,16 @@
 module Gitlab
   module Auth
     Result = Struct.new(:actor, :project, :type, :authentication_abilities) do
-      def ci?
-        type == :ci
+      def ci?(for_project)
+        type == :ci &&
+          project &&
+          project == for_project
+      end
+
+      def lfs_deploy_token?(for_project)
+        type == :lfs_deploy_token &&
+          actor &&
+          actor.projects.include?(for_project)
       end
 
       def success?
diff --git a/lib/gitlab/lfs_token.rb b/lib/gitlab/lfs_token.rb
new file mode 100644
index 00000000000..d089a2f9b0b
--- /dev/null
+++ b/lib/gitlab/lfs_token.rb
@@ -0,0 +1,54 @@
+module Gitlab
+  class LfsToken
+    attr_accessor :actor
+
+    TOKEN_LENGTH = 50
+    EXPIRY_TIME = 1800
+
+    def initialize(actor)
+      @actor =
+        case actor
+        when DeployKey, User
+          actor
+        when Key
+          actor.user
+        else
+          raise 'Bad Actor'
+        end
+    end
+
+    def generate
+      token = Devise.friendly_token(TOKEN_LENGTH)
+
+      Gitlab::Redis.with do |redis|
+        redis.set(redis_key, token, ex: EXPIRY_TIME)
+      end
+
+      token
+    end
+
+    def value
+      Gitlab::Redis.with do |redis|
+        redis.get(redis_key)
+      end
+    end
+
+    def user?
+      actor.is_a?(User)
+    end
+
+    def type
+      actor.is_a?(User) ? :lfs_token : :lfs_deploy_token
+    end
+
+    def actor_name
+      actor.is_a?(User) ? actor.username : "lfs+deploy-key-#{actor.id}"
+    end
+
+    private
+
+    def redis_key
+      "gitlab:lfs_token:#{actor.class.name.underscore}_#{actor.id}" if actor
+    end
+  end
+end
diff --git a/spec/lib/gitlab/auth_spec.rb b/spec/lib/gitlab/auth_spec.rb
index 8807a68a0a2..745fbc0df45 100644
--- a/spec/lib/gitlab/auth_spec.rb
+++ b/spec/lib/gitlab/auth_spec.rb
@@ -61,6 +61,24 @@ describe Gitlab::Auth, lib: true do
       expect(gl_auth.find_for_git_client(user.username, 'password', project: nil, ip: ip)).to eq(Gitlab::Auth::Result.new(user, nil, :gitlab_or_ldap, full_authentication_abilities))
     end
 
+    it 'recognizes user lfs tokens' do
+      user = create(:user)
+      ip = 'ip'
+      token = Gitlab::LfsToken.new(user).generate
+
+      expect(gl_auth).to receive(:rate_limit!).with(ip, success: true, login: user.username)
+      expect(gl_auth.find_for_git_client(user.username, token, project: nil, ip: ip)).to eq(Gitlab::Auth::Result.new(user, nil, :lfs_token, full_authentication_abilities))
+    end
+
+    it 'recognizes deploy key lfs tokens' do
+      key = create(:deploy_key)
+      ip = 'ip'
+      token = Gitlab::LfsToken.new(key).generate
+
+      expect(gl_auth).to receive(:rate_limit!).with(ip, success: true, login: "lfs+deploy-key-#{key.id}")
+      expect(gl_auth.find_for_git_client("lfs+deploy-key-#{key.id}", token, project: nil, ip: ip)).to eq(Gitlab::Auth::Result.new(key, nil, :lfs_deploy_token, read_authentication_abilities))
+    end
+
     it 'recognizes OAuth tokens' do
       user = create(:user)
       application = Doorkeeper::Application.create!(name: "MyApp", redirect_uri: "https://app.com", owner: user)
diff --git a/spec/lib/gitlab/lfs_token_spec.rb b/spec/lib/gitlab/lfs_token_spec.rb
new file mode 100644
index 00000000000..9f04f67e0a8
--- /dev/null
+++ b/spec/lib/gitlab/lfs_token_spec.rb
@@ -0,0 +1,51 @@
+require 'spec_helper'
+
+describe Gitlab::LfsToken, lib: true do
+  describe '#generate and #value' do
+    shared_examples 'an LFS token generator' do
+      it 'returns a randomly generated token' do
+        token = handler.generate
+
+        expect(token).not_to be_nil
+        expect(token).to be_a String
+        expect(token.length).to eq 50
+      end
+
+      it 'returns the correct token based on the key' do
+        token = handler.generate
+
+        expect(handler.value).to eq(token)
+      end
+    end
+
+    context 'when the actor is a user' do
+      let(:actor) { create(:user) }
+      let(:handler) { described_class.new(actor) }
+
+      it_behaves_like 'an LFS token generator'
+
+      it 'returns the correct username' do
+        expect(handler.actor_name).to eq(actor.username)
+      end
+
+      it 'returns the correct token type' do
+        expect(handler.type).to eq(:lfs_token)
+      end
+    end
+
+    context 'when the actor is a deploy key' do
+      let(:actor) { create(:deploy_key) }
+      let(:handler) { described_class.new(actor) }
+
+      it_behaves_like 'an LFS token generator'
+
+      it 'returns the correct username' do
+        expect(handler.actor_name).to eq("lfs+deploy-key-#{actor.id}")
+      end
+
+      it 'returns the correct token type' do
+        expect(handler.type).to eq(:lfs_deploy_token)
+      end
+    end
+  end
+end
diff --git a/spec/requests/api/internal_spec.rb b/spec/requests/api/internal_spec.rb
index 46d1b868782..46e8e6f1169 100644
--- a/spec/requests/api/internal_spec.rb
+++ b/spec/requests/api/internal_spec.rb
@@ -100,6 +100,43 @@ describe API::API, api: true  do
     end
   end
 
+  describe "POST /internal/lfs_authenticate" do
+    before do
+      project.team << [user, :developer]
+    end
+
+    context 'user key' do
+      it 'returns the correct information about the key' do
+        lfs_auth(key.id, project)
+
+        expect(response).to have_http_status(200)
+        expect(json_response['username']).to eq(user.username)
+        expect(json_response['lfs_token']).to eq(Gitlab::LfsToken.new(key).value)
+
+        expect(json_response['repository_http_path']).to eq(project.http_url_to_repo)
+      end
+
+      it 'returns a 404 when the wrong key is provided' do
+        lfs_auth(nil, project)
+
+        expect(response).to have_http_status(404)
+      end
+    end
+
+    context 'deploy key' do
+      let(:key) { create(:deploy_key) }
+
+      it 'returns the correct information about the key' do
+        lfs_auth(key.id, project)
+
+        expect(response).to have_http_status(200)
+        expect(json_response['username']).to eq("lfs+deploy-key-#{key.id}")
+        expect(json_response['lfs_token']).to eq(Gitlab::LfsToken.new(key).value)
+        expect(json_response['repository_http_path']).to eq(project.http_url_to_repo)
+      end
+    end
+  end
+
   describe "GET /internal/discover" do
     it do
       get(api("/internal/discover"), key_id: key.id, secret_token: secret_token)
@@ -389,4 +426,13 @@ describe API::API, api: true  do
       protocol: 'ssh'
     )
   end
+
+  def lfs_auth(key_id, project)
+    post(
+      api("/internal/lfs_authenticate"),
+      key_id: key_id,
+      secret_token: secret_token,
+      project: project.path_with_namespace
+    )
+  end
 end
diff --git a/spec/requests/lfs_http_spec.rb b/spec/requests/lfs_http_spec.rb
index b58d410b7a3..09e4e265dd1 100644
--- a/spec/requests/lfs_http_spec.rb
+++ b/spec/requests/lfs_http_spec.rb
@@ -245,6 +245,18 @@ describe 'Git LFS API and storage' do
           end
         end
 
+        context 'when deploy key is authorized' do
+          let(:key) { create(:deploy_key) }
+          let(:authorization) { authorize_deploy_key }
+
+          let(:update_permissions) do
+            project.deploy_keys << key
+            project.lfs_objects << lfs_object
+          end
+
+          it_behaves_like 'responds with a file'
+        end
+
         context 'when build is authorized as' do
           let(:authorization) { authorize_ci_project }
 
@@ -1097,6 +1109,10 @@ describe 'Git LFS API and storage' do
     ActionController::HttpAuthentication::Basic.encode_credentials(user.username, user.password)
   end
 
+  def authorize_deploy_key
+    ActionController::HttpAuthentication::Basic.encode_credentials("lfs+deploy-key-#{key.id}", Gitlab::LfsToken.new(key).generate)
+  end
+
   def fork_project(project, user, object = nil)
     allow(RepositoryForkWorker).to receive(:perform_async).and_return(true)
     Projects::ForkService.new(project, user, {}).execute