It's not safe to Load InitType with type name only #382

rugbbyli · 2020-05-12T02:16:45Z

Sorry, this issue is for ClojureCLR (https://github.com/arcadia-unity/clojure-clr), but that project does not accept issue, so i write it here.

When ClojureCLR invoke a clojure code, it iterate over all assemblies and find the type with initClassName matched. source code here:

        internal static bool TryLoadInitType(string relativePath)
        {
            var initClassName = InitClassName(relativePath);
            Type initType = null;
            foreach (var asm in AppDomain.CurrentDomain.GetAssemblies())
            {
#if CLR2
                if(asm.ManifestModule is ModuleBuilder)
#else
                if (asm.IsDynamic)
#endif
                    continue;
                initType = asm.GetType(initClassName);
                if (initType != null)
                    break;
            }
            if (initType == null)
                return false;

            InvokeInitType(initType.Assembly, initType);
            return true;
        }

But it's not safe, as there may be another type have a same name , and would be wrongly loaded.

To prevent this situation, we could double check using excepted assembly name, like this:

        internal static bool TryLoadInitType(string relativePath)
        {
            var initClassName = InitClassName(relativePath);
            Type initType = null;
            var asmName = relativePath.Replace('/', '.') + ".clj";
            foreach (var asm in AppDomain.CurrentDomain.GetAssemblies())
            {
#if CLR2
                if(asm.ManifestModule is ModuleBuilder)
#else
                if (asm.IsDynamic)
#endif
                    continue;
                if(!asm.GetName(false).Name.StartsWith(asmName))
                    continue;
                initType = asm.GetType(initClassName);
                if (initType != null)
                    break;
            }
            if (initType == null)
                return false;

            InvokeInitType(initType.Assembly, initType);
            return true;
        }

nasser · 2020-05-24T18:58:59Z

that's a fair point. this is not an issue in practice, because the name of the type returned by InitClassName has symbols like $ in it, so you could not actually write a type with such a name in c# (or even in clojure, because we prefix type names with the namespaces they were defined in). an additional check would not hurt anything, though. i am focused on finishing MAGIC for the next few months so i will not be able to hack on ClojureCLR myself. if you want to take out a PR against https://github.com/arcadia-unity/clojure-clr i will merge that in once you've signed the clojure contributor's agreement (required by upstream).

rugbbyli · 2020-05-28T04:55:34Z

Yes, normally it's safe, while when building in Unity3D and enable strip code, it made an "Incompatibility" with unity3d linker, and cause a bug here.
Personally, i thought it may be a problem with unity, but that's a complex prove, and could easier bypass it using the way above.
I would check the clojure contributor agreement later and try to make a PR.

arcadia-unity / Arcadia

It's not safe to Load InitType with type name only #382

It's not safe to Load InitType with type name only #382

rugbbyli commented May 12, 2020

nasser commented May 24, 2020

rugbbyli commented May 28, 2020

arcadia-unity / Arcadia

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It's not safe to Load InitType with type name only #382

It's not safe to Load InitType with type name only #382

Comments

rugbbyli commented May 12, 2020

nasser commented May 24, 2020

rugbbyli commented May 28, 2020

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