X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/5d00ecb0932f86e4d2aced3d9258b96522ef38bd..HEAD:/services/api/app/models/link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index d38ea59083..2eb6b88a0c 100644
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -1,14 +1,28 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
 class Link < ArvadosModel
   include HasUuid
   include KindAndEtag
   include CommonApiTemplate
-  serialize :properties, Hash
-  before_create :permission_to_attach_to_objects
-  before_update :permission_to_attach_to_objects
-  after_update :maybe_invalidate_permissions_cache
-  after_create :maybe_invalidate_permissions_cache
-  after_destroy :maybe_invalidate_permissions_cache
+
+  # Posgresql JSONB columns should NOT be declared as serialized, Rails 5
+  # already know how to properly treat them.
+  attribute :properties, :jsonbHash, default: {}
+
   validate :name_links_are_obsolete
+  validate :permission_to_attach_to_objects
+  before_update :restrict_alter_permissions
+  before_update :apply_max_overlapping_permissions
+  before_create :apply_max_overlapping_permissions
+  after_update :delete_overlapping_permissions
+  after_update :call_update_permissions, :if => Proc.new { @need_update_permissions }
+  after_create :call_update_permissions, :if => Proc.new { @need_update_permissions }
+  before_destroy :clear_permissions
+  after_destroy :delete_overlapping_permissions
+  after_destroy :check_permissions
+  before_save :check_need_update_permissions
 
   api_accessible :user, extend: :common do |t|
     t.add :tail_uuid
@@ -20,6 +34,58 @@ class Link < ArvadosModel
     t.add :properties
   end
 
+  PermLevel = {
+    'can_read' => 0,
+    'can_write' => 1,
+    'can_manage' => 2,
+  }
+
+  def apply_max_overlapping_permissions
+    return if self.link_class != 'permission' || !PermLevel[self.name]
+    Link.
+      lock. # select ... for update
+      where(link_class: 'permission',
+            tail_uuid: self.tail_uuid,
+            head_uuid: self.head_uuid,
+            name: PermLevel.keys).
+      where('uuid <> ?', self.uuid).each do |other|
+      if PermLevel[other.name] > PermLevel[self.name]
+        self.name = other.name
+      end
+    end
+  end
+
+  def delete_overlapping_permissions
+    return if self.link_class != 'permission'
+    redundant = nil
+    if PermLevel[self.name]
+      redundant = Link.
+                    lock. # select ... for update
+                    where(link_class: 'permission',
+                          tail_uuid: self.tail_uuid,
+                          head_uuid: self.head_uuid,
+                          name: PermLevel.keys).
+                    where('uuid <> ?', self.uuid)
+    elsif self.name == 'can_login' &&
+          self.properties.respond_to?(:has_key?) &&
+          self.properties.has_key?('username')
+      redundant = Link.
+                    lock. # select ... for update
+                    where(link_class: 'permission',
+                          tail_uuid: self.tail_uuid,
+                          head_uuid: self.head_uuid,
+                          name: 'can_login').
+                    where('properties @> ?', SafeJSON.dump({'username' => self.properties['username']})).
+                    where('uuid <> ?', self.uuid)
+    end
+    if redundant
+      redundant.each do |link|
+        link.clear_permissions
+      end
+      redundant.delete_all
+    end
+  end
+
   def head_kind
     if k = ArvadosModel::resource_class_for_uuid(head_uuid)
       k.kind
@@ -34,6 +100,28 @@ class Link < ArvadosModel
 
   protected
 
+  def check_readable_uuid attr, attr_value
+    if attr == 'tail_uuid' &&
+       !attr_value.nil? &&
+       self.link_class == 'permission' &&
+       attr_value[0..4] != Rails.configuration.ClusterID &&
+       ApiClientAuthorization.remote_host(uuid_prefix: attr_value[0..4]) &&
+       ArvadosModel::resource_class_for_uuid(attr_value) == User
+      # Permission link tail is a remote user (the user permissions
+      # are being granted to), so bypass the standard check that a
+      # referenced object uuid is readable by current user.
+      #
+      # We could do a call to the remote cluster to check if the user
+      # in tail_uuid exists.  This would detect copy-and-paste errors,
+      # but add another way for the request to fail, and I don't think
+      # it would improve security.  It doesn't seem to be worth the
+      # complexity tradeoff.
+      true
+    else
+      super
+    end
+  end
+
   def permission_to_attach_to_objects
     # Anonymous users cannot write links
     return false if !current_user
@@ -41,26 +129,86 @@ class Link < ArvadosModel
     # All users can write links that don't affect permissions
     return true if self.link_class != 'permission'
 
+    if PERM_LEVEL[self.name].nil?
+      errors.add(:name, "is invalid permission, must be one of 'can_read', 'can_write', 'can_manage', 'can_login'")
+      return false
+    end
+
+    rsc_class = ArvadosModel::resource_class_for_uuid tail_uuid
+    if rsc_class == Group
+      tail_obj = Group.find_by_uuid(tail_uuid)
+      if tail_obj.nil?
+        errors.add(:tail_uuid, "does not exist")
+        return false
+      end
+      if tail_obj.group_class != "role"
+        errors.add(:tail_uuid, "must be a user or role, was group with group_class #{tail_obj.group_class}")
+        return false
+      end
+    elsif rsc_class != User
+      errors.add(:tail_uuid, "must be a user or role")
+      return false
+    end
+
     # Administrators can grant permissions
     return true if current_user.is_admin
 
-    # All users can grant permissions on objects they own or can manage
     head_obj = ArvadosModel.find_by_uuid(head_uuid)
+
+    if head_obj.nil?
+      errors.add(:head_uuid, "does not exist")
+      return false
+    end
+
+    # No permission links can be pointed to past collection versions
+    if head_obj.is_a?(Collection) && head_obj.current_version_uuid != head_uuid
+      errors.add(:head_uuid, "cannot point to a past version of a collection")
+      return false
+    end
+
+    # All users can grant permissions on objects they own or can manage
     return true if current_user.can?(manage: head_obj)
 
     # Default = deny.
     false
   end
 
-  def maybe_invalidate_permissions_cache
+  def restrict_alter_permissions
+    return true if self.link_class != 'permission' && self.link_class_was != 'permission'
+
+    return true if current_user.andand.uuid == system_user.uuid
+
+    if link_class_changed? || tail_uuid_changed? || head_uuid_changed?
+      raise "Can only alter permission link level"
+    end
+  end
+
+  PERM_LEVEL = {
+    'can_read' => 1,
+    'can_login' => 1,
+    'can_write' => 2,
+    'can_manage' => 3,
+  }
+
+  def check_need_update_permissions
+    @need_update_permissions = self.link_class == 'permission' && (name != name_was || new_record?)
+  end
+
+  def call_update_permissions
+      update_permissions tail_uuid, head_uuid, PERM_LEVEL[name], self.uuid
+      current_user.forget_cached_group_perms
+  end
+
+  def clear_permissions
     if self.link_class == 'permission'
-      # Clearing the entire permissions cache can generate many
-      # unnecessary queries if many active users are not affected by
-      # this change. In such cases it would be better to search cached
-      # permissions for head_uuid and tail_uuid, and invalidate the
-      # cache for only those users. (This would require a browseable
-      # cache.)
-      User.invalidate_permissions_cache db_current_time.to_i
+      update_permissions tail_uuid, head_uuid, REVOKE_PERM, self.uuid
+      current_user.forget_cached_group_perms
+    end
+  end
+
+  def check_permissions
+    if self.link_class == 'permission'
+      check_permissions_against_full_refresh
     end
   end
 
@@ -90,5 +238,4 @@ class Link < ArvadosModel
       super
     end
   end
-
 end