Workaround Gitiles bug on All-Users visibility

Gitiles has special FilteredRepository wrapper that
allows to carefully hide refs based on the project's ACLs.
There is however an optimisation that skips the filtering
in case a user has READ permissions on every ACLs patterns.

When the target repository is All-Users, the optimisation
turns into a security issue because it allows seeing everything
that belongs to everyone:
- draft comments
- PII of all users
- external ids
- draft edits

Block Gitiles or any other part of Gerrit to abuse of this
power when the target repository is All-Users, where nobody
can be authorised to skip the ACLs evaluation.

Cover the additional special case of the All-Users project
access with two explicit positive and negative tests,
so that the security check is covered.

Bug: Issue 13621
Change-Id: Ia6ea1a9fd5473adff534204aea7d8f25324a45b7
(cherry picked from commit 45071d6977932bca5a1427c8abad24710fed2e33)

2 files changed, 43 insertions, 4 deletions

diff --git a/java/com/google/gerrit/server/permissions/ProjectControl.java b/java/com/google/gerrit/server/permissions/ProjectControl.java
index c3d0719283..85e7fb16b4 100644
--- a/java/com/google/gerrit/server/permissions/ProjectControl.java
+++ b/java/com/google/gerrit/server/permissions/ProjectControl.java
@@ -33,6 +33,7 @@ import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.GroupMembership;
+import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.GitReceivePackGroups;
 import com.google.gerrit.server.config.GitUploadPackGroups;
 import com.google.gerrit.server.git.GitRepositoryManager;
@@ -75,6 +76,7 @@ class ProjectControl {
   private final ChangeControl.Factory changeControlFactory;
   private final PermissionCollection.Factory permissionFilter;
   private final DefaultRefFilter.Factory refFilterFactory;
+  private final AllUsersName allUsersName;
 
   private List<SectionMatcher> allSections;
   private Map<String, RefControl> refControls;
@@ -90,6 +92,7 @@ class ProjectControl {
       RefVisibilityControl refVisibilityControl,
       GitRepositoryManager repositoryManager,
       DefaultRefFilter.Factory refFilterFactory,
+      AllUsersName allUsersName,
       @Assisted CurrentUser who,
       @Assisted ProjectState ps) {
     this.changeControlFactory = changeControlFactory;
@@ -100,6 +103,7 @@ class ProjectControl {
     this.refVisibilityControl = refVisibilityControl;
     this.repositoryManager = repositoryManager;
     this.refFilterFactory = refFilterFactory;
+    this.allUsersName = allUsersName;
     user = who;
     state = ps;
   }
@@ -175,7 +179,9 @@ class ProjectControl {
   }
 
   boolean allRefsAreVisible(Set<String> ignore) {
-    return user.isInternalUser() || canPerformOnAllRefs(Permission.READ, ignore);
+    return user.isInternalUser()
+        || (!getProject().getNameKey().equals(allUsersName)
+            && canPerformOnAllRefs(Permission.READ, ignore));
   }
 
   /** Can the user run upload pack? */
diff --git a/javatests/com/google/gerrit/server/permissions/RefControlTest.java b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
index bf8ea86f02..0f0f1c3ec1 100644
--- a/javatests/com/google/gerrit/server/permissions/RefControlTest.java
+++ b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
@@ -106,6 +106,14 @@ public class RefControlTest {
     assertThat(u.isOwner()).named("not owner").isFalse();
   }
 
+  private void assertAllRefsAreVisible(ProjectControl u) {
+    assertThat(u.allRefsAreVisible(Collections.emptySet())).named("all refs visible").isTrue();
+  }
+
+  private void assertAllRefsAreNotVisible(ProjectControl u) {
+    assertThat(u.allRefsAreVisible(Collections.emptySet())).named("all refs NOT visible").isFalse();
+  }
+
   private void assertNotOwner(String ref, ProjectControl u) {
     assertThat(u.controlForRef(ref).isOwner()).named("NOT OWN " + ref).isFalse();
   }
@@ -195,6 +203,7 @@ public class RefControlTest {
   private final Map<Project.NameKey, ProjectState> all = new HashMap<>();
   private Project.NameKey localKey = new Project.NameKey("local");
   private ProjectConfig local;
+  private ProjectConfig allUsers;
   private Project.NameKey parentKey = new Project.NameKey("parent");
   private ProjectConfig parent;
   private InMemoryRepositoryManager repoManager;
@@ -226,7 +235,7 @@ public class RefControlTest {
 
           @Override
           public ProjectState getAllUsers() {
-            return null;
+            return get(allUsersName);
           }
 
           @Override
@@ -280,12 +289,17 @@ public class RefControlTest {
     injector.injectMembers(this);
 
     try {
-      Repository repo = repoManager.createRepository(allProjectsName);
+      Repository allProjectsRepo = repoManager.createRepository(allProjectsName);
       ProjectConfig allProjects = new ProjectConfig(new Project.NameKey(allProjectsName.get()));
-      allProjects.load(repo);
+      allProjects.load(allProjectsRepo);
       LabelType cr = Util.codeReview();
       allProjects.getLabelSections().put(cr.getName(), cr);
       add(allProjects);
+
+      Repository allUsersRepo = repoManager.createRepository(allUsersName);
+      allUsers = new ProjectConfig(new Project.NameKey(allUsersName.get()));
+      allUsers.load(allUsersRepo);
+      add(allUsers);
     } catch (IOException | ConfigInvalidException e) {
       throw new RuntimeException(e);
     }
@@ -360,6 +374,24 @@ public class RefControlTest {
   }
 
   @Test
+  public void allRefsAreVisibleForRegularProject() throws Exception {
+    allow(local, READ, DEVS, "refs/*");
+    allow(local, READ, DEVS, "refs/groups/*");
+    allow(local, READ, DEVS, "refs/users/default");
+
+    assertAllRefsAreVisible(user(local, DEVS));
+  }
+
+  @Test
+  public void allRefsAreNotVisibleForAllUsers() throws Exception {
+    allow(allUsers, READ, DEVS, "refs/*");
+    allow(allUsers, READ, DEVS, "refs/groups/*");
+    allow(allUsers, READ, DEVS, "refs/users/default");
+
+    assertAllRefsAreNotVisible(user(allUsers, DEVS));
+  }
+
+  @Test
   public void branchDelegation1() throws Exception {
     allow(local, OWNER, ADMIN, "refs/*");
     allow(local, OWNER, DEVS, "refs/heads/x/*");
@@ -1022,6 +1054,7 @@ public class RefControlTest {
         refVisibilityControl,
         repoManager,
         refFilterFactory,
+        allUsersName,
         new MockUser(name, memberOf),
         newProjectState(local));
   }