[GR-18163] Fix file permissions predicates for superuser

PullRequest: truffleruby/3429

Author: andrykonchin

CHANGELOG.md

@@ -8,6 +8,7 @@ Bug fixes:
 
 * Fix `StringIO` to set position correctly after reading multi-byte characters (#2207, @aardvark179).
 * Update `Process` methods to use `module_function` (@bjfish).
+* Fix `File::Stat`'s `#executable?` and `#executable_real?` predicates that unconditionally returned `true` for a superuser (#2690, @andrykonchin).
 
 Compatibility:
 

spec/mspec/lib/mspec/guards/superuser.rb

@@ -6,10 +6,20 @@ def match?
   end
 end
 
+class RealSuperUserGuard < SpecGuard
+  def match?
+    Process.uid == 0
+  end
+end
+
 def as_superuser(&block)
   SuperUserGuard.new.run_if(:as_superuser, &block)
 end
 
+def as_real_superuser(&block)
+  RealSuperUserGuard.new.run_if(:as_real_superuser, &block)
+end
+
 def as_user(&block)
   SuperUserGuard.new.run_unless(:as_user, &block)
 end

spec/ruby/shared/file/executable.rb

@@ -39,6 +39,41 @@
     -> { @object.send(@method, nil)   }.should raise_error(TypeError)
     -> { @object.send(@method, false) }.should raise_error(TypeError)
   end
+
+  platform_is_not :windows do
+    as_superuser do
+      context "when run by a superuser" do
+        before :each do
+          @file = tmp('temp3.txt')
+          touch @file
+        end
+
+        after :each do
+          rm_r @file
+        end
+
+        it "returns true if file owner has permission to execute" do
+          File.chmod(0766, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "returns true if group has permission to execute" do
+          File.chmod(0676, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "returns true if other have permission to execute" do
+          File.chmod(0667, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "return false if nobody has permission to execute" do
+          File.chmod(0666, @file)
+          @object.send(@method, @file).should == false
+        end
+      end
+    end
+  end
 end
 
 describe :file_executable_missing, shared: true do

spec/ruby/shared/file/executable_real.rb

@@ -37,6 +37,41 @@
     -> { @object.send(@method, nil)   }.should raise_error(TypeError)
     -> { @object.send(@method, false) }.should raise_error(TypeError)
   end
+
+  platform_is_not :windows do
+    as_real_superuser do
+      context "when run by a real superuser" do
+        before :each do
+          @file = tmp('temp3.txt')
+          touch @file
+        end
+
+        after :each do
+          rm_r @file
+        end
+
+        it "returns true if file owner has permission to execute" do
+          File.chmod(0766, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "returns true if group has permission to execute" do
+          File.chmod(0676, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "returns true if other have permission to execute" do
+          File.chmod(0667, @file)
+          @object.send(@method, @file).should == true
+        end
+
+        it "return false if nobody has permission to execute" do
+          File.chmod(0666, @file)
+          @object.send(@method, @file).should == false
+        end
+      end
+    end
+  end
 end
 
 describe :file_executable_real_missing, shared: true do

spec/ruby/shared/file/readable.rb

@@ -24,6 +24,22 @@
   it "accepts an object that has a #to_path method" do
     @object.send(@method, mock_to_path(@file2)).should == true
   end
+
+  platform_is_not :windows do
+    as_superuser do
+      context "when run by a superuser" do
+        it "returns true unconditionally" do
+          file = tmp('temp.txt')
+          touch file
+
+          File.chmod(0333, file)
+          @object.send(@method, file).should == true
+
+          rm_r file
+        end
+      end
+    end
+  end
 end
 
 describe :file_readable_missing, shared: true do

spec/ruby/shared/file/readable_real.rb

@@ -14,6 +14,22 @@
   it "accepts an object that has a #to_path method" do
     File.open(@file,'w') { @object.send(@method, mock_to_path(@file)).should == true }
   end
+
+  platform_is_not :windows do
+    as_real_superuser do
+      context "when run by a real superuser" do
+        it "returns true unconditionally" do
+          file = tmp('temp.txt')
+          touch file
+
+          File.chmod(0333, file)
+          @object.send(@method, file).should == true
+
+          rm_r file
+        end
+      end
+    end
+  end
 end
 
 describe :file_readable_real_missing, shared: true do

spec/ruby/shared/file/writable.rb

@@ -19,6 +19,22 @@
   it "accepts an object that has a #to_path method" do
     File.open(@file,'w') { @object.send(@method, mock_to_path(@file)).should == true }
   end
+
+  platform_is_not :windows do
+    as_superuser do
+      context "when run by a superuser" do
+        it "returns true unconditionally" do
+          file = tmp('temp.txt')
+          touch file
+
+          File.chmod(0555, file)
+          @object.send(@method, file).should == true
+
+          rm_r file
+        end
+      end
+    end
+  end
 end
 
 describe :file_writable_missing, shared: true do

spec/ruby/shared/file/writable_real.rb

@@ -24,6 +24,22 @@
     -> { @object.send(@method, nil)   }.should raise_error(TypeError)
     -> { @object.send(@method, false) }.should raise_error(TypeError)
   end
+
+  platform_is_not :windows do
+    as_real_superuser do
+      context "when run by a real superuser" do
+        it "returns true unconditionally" do
+          file = tmp('temp.txt')
+          touch file
+
+          File.chmod(0555, file)
+          @object.send(@method, file).should == true
+
+          rm_r file
+        end
+      end
+    end
+  end
 end
 
 describe :file_writable_real_missing, shared: true do

src/main/ruby/truffleruby/core/stat.rb

@@ -131,14 +131,14 @@ def directory?
     end
 
     def executable?
-      return true if superuser?
+      return mode & S_IXUGO != 0 if superuser?
       return mode & S_IXUSR != 0 if owned?
       return mode & S_IXGRP != 0 if grpowned?
       mode & S_IXOTH != 0
     end
 
     def executable_real?
-      return true if rsuperuser?
+      return mode & S_IXUGO != 0 if rsuperuser?
       return mode & S_IXUSR != 0 if rowned?
       return mode & S_IXGRP != 0 if rgrpowned?
       mode & S_IXOTH != 0