Description

Wasm3 fails to validate the type of the argument passed to the br_table instruction. According to the WebAssembly specification, the index parameter used in br_table must have the type i32. However, Wasm3 does not enforce this validation, allowing an argument with an invalid type (e.g., i64) to bypass validation and execute, leading to undefined behavior.

Environment

$ ./wasm3 --version
Wasm3 v0.5.0 on x86_64
Build: May 28 2024 20:38:13, Ubuntu Clang 19.0.0

Steps to Reproduce

Run the following WebAssembly module:

(module
  (func $main (result i32)
    (local $index i64)
    (local.set $index (i64.const 2))

    (block $block0
      (block $block1
        (block $block2
          (block $block3
            (br_table $block0 $block1 $block2 $block3 (local.get $index))
          )
          i32.const 3
          return
        )
        i32.const 2
        return
      )
      i32.const 1
      return
    )
    i32.const 0
  )

  (export "main" (func $main))
)

Execute the module using Wasm3:

$ ./wasm3 --func main /path/to/program.wasm
Result: 2

Expected Behavior

According to the WebAssembly specification, the index parameter for the br_table instruction must be of type i32. If the argument type is invalid (e.g., i64), the module must fail validation with an error such as:

br_table with non-i32 condition I64