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This is a list of the instructions that make up the Java bytecode, an abstract machine language that is ultimately executed by the Java virtual machine. [1] The Java bytecode is generated from languages running on the Java Platform, most notably the Java programming language.
This type of stack implementation is extremely common, but it is vulnerable to buffer overflow attacks (see the text). A number of programming languages are stack-oriented, meaning they define most basic operations (adding two numbers, printing a character) as taking their arguments from the stack, and placing any return values back on the stack.
Java bytecode is used at runtime either interpreted by a JVM or compiled to machine code via just-in-time (JIT) compilation and run as a native application. As Java bytecode is designed for a cross-platform compatibility and security, a Java bytecode application tends to run consistently across various hardware and software configurations. [3]
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere (), [16] meaning that compiled Java code can run on all platforms that support Java without the need to recompile. [17]
Character; Floating-point representation of a finite subset of the rationals. Including single-precision and double-precision IEEE 754 floats, among others; Fixed-point representation of the rationals; Integer, a direct representation of either the integers or the non-negative integers
Typical Java interpreters do not buffer the top-of-stack this way, however, because the program and stack have a mix of short and wide data values. If the hardwired stack machine has 2 or more top-stack registers, or a register file, then all memory access is avoided in this example and there is only 1 data cache cycle.
Thus, the attacker has overwritten the return address with a pointer to the stack buffer char c[12], which now contains attacker-supplied data. In an actual stack buffer overflow exploit the string of "A"'s would instead be shellcode suitable to the platform and desired function.
Push local variable onto stack IN N/A Reads a character from the keyboard buffer and pushes it onto the stack. If no character is available, 0 is pushed INVOKEVIRTUAL method name Invoke a method, pops object reference and optionally pops arguments from stack. IOR N/A Pop two words from stack; push Boolean OR IRETURN N/A