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124 lines
2.8 KiB
124 lines
2.8 KiB
; This class converts between boolean and ints without type casts.
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; You can't decompile this directly, the decompiler probably gives type errors.
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.class public EvilTypes
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.super java/lang/Object
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.field public static runner Ljava/lang/Runnable;
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.method public static boolToInt(Z)I
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.limit locals 1
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.limit stack 1
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iload_0
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ireturn
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.end method
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.method public static intToBool(I)Z
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.limit locals 1
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.limit stack 1
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iload_0
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ireturn
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.end method
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.method public static overrideParam(I)[I
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.limit locals 1
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.limit stack 1
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aconst_null
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astore_0
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aload_0
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areturn
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.end method
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.method public static test()V
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.limit locals 2
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.limit stack 2
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iconst_1
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invokestatic EvilTypes/intToBool(I)Z
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istore 0
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iconst_2
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istore 1
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iload 0
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iload 1
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ixor
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pop
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return
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.end method
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.method private static useSerial(Ljava/io/Serializable;)V
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.limit locals 1
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.limit stack 0
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return
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.end method
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; This is a test where a type error occurs, because there is no Type
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; that implements Cloneable, Serializable and is assignable form int
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; array and java/lang/Date (though both objects are Cloneable and
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; Serializable). We can't find any correct type for local 2.
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.method public static referenceCast(Ljava/util/Date;[I)Ljava/lang/Cloneable;
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.limit locals 3
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.limit stack 2
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aload_0
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ifnonnull second
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aload_0
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goto done
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second:
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aload_1
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done:
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dup
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astore_2
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invokestatic EvilTypes/useSerial(Ljava/io/Serializable;)V
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aload_2
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areturn
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.end method
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; This shows that the bytecode verifier doesn't catch every type error.
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.method public static test(Ljava/lang/String;)Ljava/lang/Runnable;
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.limit locals 1
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.limit stack 1
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aload_0
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areturn
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.end method
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; The problem of this method is the type of local_0, the code is as
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; follows:
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; local_0 = null;
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; for (;;) local_0 = local_0[0];
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;
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; Since local_0 is used as an array, it must be of array type. Since
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; local_0[0] is assigned to local_0, local_0[0] must be of array type,
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; so local_0 must be of type array of array of something, and so on...
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.method public static infinitiveArray()V
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.limit locals 1
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.limit stack 2
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aconst_null
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astore_0
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loop:
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aload_0
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iconst_0
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aaload
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astore_0
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goto loop
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.end method
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; This tests shows how lazy the type checking even with verify is:
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; The type error produced in the test method, is first seen on the
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; invokeinterface opcode. If there would be no invokeinterface it
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; would never have been noticed.
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; NOTE: An obfuscator may use this fact and replace every ocurrence
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; of an interface or Object type with any other interface type.
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.method public static main([Ljava/lang/String;)V
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.limit locals 1
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.limit stack 2
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aload_0
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iconst_0
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aaload
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invokestatic EvilTypes/test(Ljava/lang/String;)Ljava/lang/Runnable;
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putstatic EvilTypes/runner Ljava/lang/Runnable;
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getstatic EvilTypes/runner Ljava/lang/Runnable;
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invokeinterface java/lang/Runnable/run()V 1
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return
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.end method
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