core: Non-root movies that AVM1 loads should always be considered AVM1

core/common/src/tag_utils.rs

@@ -39,6 +39,10 @@ pub struct SwfMovie {
     /// something else, like an loaded image, filler movie, or error state.
     is_movie: bool,
 
+    /// Whether this movie should be interpreted as AVM1, regardless of what the
+    /// header declares.
+    force_avm1: bool,
+
     /// Security sandbox type enforced for this movie.
     ///
     /// It absolutely cannot be changed after constructing
@@ -63,6 +67,7 @@ impl SwfMovie {
             encoding: swf::UTF_8,
             compressed_len: 0,
             is_movie: false,
+            force_avm1: false,
             sandbox_type,
         }
     }
@@ -90,6 +95,7 @@ impl SwfMovie {
             parameters: Vec::new(),
             encoding: swf::UTF_8,
             is_movie: false,
+            force_avm1: false,
             sandbox_type,
         }
     }
@@ -115,6 +121,7 @@ impl SwfMovie {
             parameters: Vec::new(),
             encoding: swf::UTF_8,
             is_movie: false,
+            force_avm1: false,
             sandbox_type,
         }
     }
@@ -138,6 +145,7 @@ impl SwfMovie {
             encoding: swf::UTF_8,
             compressed_len: 0,
             is_movie: false,
+            force_avm1: false,
             sandbox_type,
         }
     }
@@ -161,6 +169,7 @@ impl SwfMovie {
             encoding,
             compressed_len,
             is_movie: true,
+            force_avm1: false,
             sandbox_type,
         };
         movie.append_parameters_from_url();
@@ -180,6 +189,7 @@ impl SwfMovie {
             encoding: swf::UTF_8,
             compressed_len: length,
             is_movie: false,
+            force_avm1: false,
             sandbox_type,
         };
         movie.append_parameters_from_url();
@@ -242,6 +252,10 @@ impl SwfMovie {
         self.url = url;
     }
 
+    pub fn set_force_avm1(&mut self) {
+        self.force_avm1 = true;
+    }
+
     /// Get the URL that triggered the fetch of this SWF.
     pub fn loader_url(&self) -> Option<&str> {
         self.loader_url.as_deref()
@@ -263,10 +277,20 @@ impl SwfMovie {
         self.header.uncompressed_len()
     }
 
-    pub fn is_action_script_3(&self) -> bool {
+    /// Whether the SWF's FileAttributes tag declares the SWF to be AVM2.
+    pub fn is_declared_action_script_3(&self) -> bool {
         self.header.is_action_script_3()
     }
 
+    /// Whether this `SwfMovie` should be interpreted as AVM2.
+    ///
+    /// This usually is the same as `is_declared_action_script_3`, but will
+    /// return false if this is an AVM2 movie loaded by AVM1 (which we mark by
+    /// setting `force_avm1` to true).
+    pub fn is_action_script_3(&self) -> bool {
+        self.header.is_action_script_3() && !self.force_avm1
+    }
+
     pub fn stage_size(&self) -> &Rectangle<Twips> {
         self.header.stage_size()
     }

core/src/display_object/movie_clip.rs

@@ -609,7 +609,7 @@
         let mut target = self;
         loop {
             let shared = target.0.shared.get();
-            if shared.movie().is_action_script_3() {
+            if shared.movie().is_declared_action_script_3() {
                 tracing::warn!("DoInitAction tag in AVM2 movie");
                 return Ok(());
             }
@@ -652,10 +652,8 @@
         context: &mut UpdateContext<'gc>,
         reader: &mut SwfStream<'_>,
     ) -> Result<Option<Script<'gc>>, Error> {
-        if !context.root_swf.is_action_script_3() {
-            tracing::warn!("DoABC tag with non-AVM2 root");
-            return Ok(None);
-        }
+        // This is unreachable if this `MovieClip`'s movie is AVM1, as
+        // `preload_bytecode_tag` returns early if the movie is AVM1
 
         let data = reader.read_slice_to_end();
         if !data.is_empty() {
@@ -696,10 +694,8 @@
         context: &mut UpdateContext<'gc>,
         reader: &mut SwfStream<'_>,
     ) -> Result<Option<Script<'gc>>, Error> {
-        if !context.root_swf.is_action_script_3() {
-            tracing::warn!("DoABC2 tag with non-AVM2 root");
-            return Ok(None);
-        }
+        // This is unreachable if this `MovieClip`'s movie is AVM1, as
+        // `preload_bytecode_tag` returns early if the movie is AVM1
 
         let do_abc = reader.read_do_abc_2()?;
         if !do_abc.data.is_empty() {
@@ -4116,6 +4112,16 @@
         tag_code: TagCode,
         reader: &mut SwfStream<'a>,
     ) -> Result<(), Error> {
+        if !self.movie().is_action_script_3() {
+            match tag_code {
+                TagCode::DoAbc => tracing::warn!("DoABC tag in AVM1 movie"),
+                TagCode::DoAbc2 => tracing::warn!("DoABC2 tag in AVM1 movie"),
+                _ => unreachable!(),
+            }
+
+            return Ok(());
+        }
+
         let cur_frame = self.preload_progress.cur_preload_frame.get() - 1;
         let abc = match tag_code {
             TagCode::DoAbc | TagCode::DoAbc2 => {
@@ -4165,7 +4171,7 @@
         reader: &mut SwfStream<'a>,
         tag_len: usize,
     ) -> Result<(), Error> {
-        if self.movie().is_action_script_3() {
+        if self.movie().is_declared_action_script_3() {
             tracing::warn!("DoAction tag in AVM2 movie");
             return Ok(());
         }

core/src/loader.rs

@@ -1578,7 +1578,15 @@ impl<'gc> MovieLoader<'gc> {
 
         let movie = match sniffed_type {
             ContentType::Swf => {
-                Arc::new(SwfMovie::from_data(data, url.clone(), loader_url.clone())?)
+                let mut movie = SwfMovie::from_data(data, url.clone(), loader_url.clone())?;
+
+                if matches!(vm_data, MovieLoaderVMData::Avm1 { .. }) {
+                    // If AVM1 loads a SWF, that SWF is always interpreted as
+                    // AVM1, regardless of what it declares in its header.
+                    movie.set_force_avm1();
+                }
+
+                Arc::new(movie)
             }
             ContentType::Gif | ContentType::Jpeg | ContentType::Png => {
                 Arc::new(SwfMovie::from_loaded_image(url.clone(), length))

tests/tests/swfs/mixed_avm/avm1_doabc/Test.as

@@ -0,0 +1,11 @@
+{
+    trace("AVM1 shouldn't run DoABCs, so this shouldn't get printed");
+}
+
+package {
+    public class Test {
+        public function Test() {
+            super();
+        }
+    }
+}

tests/tests/swfs/mixed_avm/avm1_doabc/output.txt

@@ -0,0 +1 @@
+This trace is printed from a DoAction

tests/tests/swfs/mixed_avm/avm1_doabc/test.as

@@ -0,0 +1 @@
+trace("This trace is printed from a DoAction");

tests/tests/swfs/mixed_avm/avm1_doabc/test.toml

@@ -0,0 +1 @@
+num_frames = 1

tests/tests/swfs/mixed_avm/avm1_loads_avm2_doaction/inner-doaction.as

@@ -0,0 +1 @@
+trace("Hello from inner SWF - this shouldn't print");

tests/tests/swfs/mixed_avm/avm1_loads_avm2_doaction/inner-doinitaction.as

@@ -0,0 +1 @@
+trace("Hello from inner SWF (DoInitAction) - this shouldn't print");

tests/tests/swfs/mixed_avm/avm1_loads_avm2_doaction/outer.as

@@ -0,0 +1,4 @@
+trace("Hello from outer SWF");
+var clip = this.createEmptyMovieClip("clip", 0);
+loadMovie("avm2.swf", clip);
+trace("Outer SWF: Called loadMovie");

tests/tests/swfs/mixed_avm/avm1_loads_avm2_doaction/output.txt

@@ -0,0 +1,2 @@
+Hello from outer SWF
+Outer SWF: Called loadMovie

tests/tests/swfs/mixed_avm/avm1_sprite_sc_ignored/output.txt

@@ -0,0 +1,3 @@
+frame 1
+frame 2
+frame 3

tests/tests/swfs/mixed_avm/avm2_doaction/Test.as

@@ -0,0 +1,11 @@
+{
+    trace("This trace is printed from a DoABC");
+}
+
+package {
+    public class Test {
+        public function Test() {
+            super();
+        }
+    }
+}

tests/tests/swfs/mixed_avm/avm2_doaction/output.txt

@@ -0,0 +1 @@
+This trace is printed from a DoABC

tests/tests/swfs/mixed_avm/avm2_doaction/test.as

@@ -0,0 +1 @@
+trace("AVM2 shouldn't run DoActions, so this shouldn't get printed");

tests/tests/swfs/mixed_avm/avm2_doaction/test.toml

@@ -0,0 +1 @@
+num_frames = 1

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/Loaded.as

@@ -0,0 +1,11 @@
+{
+    trace("This shouldn\'t be traced, as the SWF is AVM1");
+}
+
+package {
+    public class Loaded {
+        public function Loaded() {
+            super();
+        }
+    }
+}

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/Test.as

@@ -0,0 +1,15 @@
+package {
+    import flash.display.Loader;
+    import flash.display.MovieClip;
+    import flash.net.URLRequest;
+
+    public class Test extends MovieClip {
+        public function Test() {
+            var l:Loader = new Loader();
+            l.load(new URLRequest("avm1.swf"));
+            addChild(l);
+
+            trace("Finished constructor of class of root MovieClip");
+        }
+    }
+}

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/frame1.as

@@ -0,0 +1 @@
+trace("Hello from DoAction tag on frame 1 of avm1.swf");

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/frame2.as

@@ -0,0 +1 @@
+trace("Hello from DoAction tag on frame 2 of avm1.swf");

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/output.txt

@@ -0,0 +1,4 @@
+Finished constructor of class of root MovieClip
+Hello from DoAction tag on frame 1 of avm1.swf
+Hello from DoAction tag on frame 2 of avm1.swf
+Hello from DoAction tag on frame 1 of avm1.swf

tests/tests/swfs/mixed_avm/avm2_loads_avm1_doabc/test.toml

@@ -0,0 +1 @@
+num_frames = 4

tests/tests/swfs/mixed_avm/avm2_loads_avm1_loads_avm2_doabc/output.txt

@@ -0,0 +1,3 @@
+Outer avm2 SWF: Called load
+AVM1 SWF: Hello from AVM1
+AVM1 SWF: Called loadMovie

tests/tests/swfs/mixed_avm/avm2_loads_avm1_loads_avm2_doabc/test.toml

@@ -0,0 +1 @@
+num_frames = 4

tests/tests/swfs/mixed_avm/avm2_loads_avm1_v10/test.toml

@@ -0,0 +1 @@
+num_frames = 3

tests/tests/swfs/mixed_avm/avm2_loads_avm1_v9/test.toml

@@ -0,0 +1 @@
+num_frames = 3