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address space layout randomization

The operating system loading a program's code, libraries, stack and heap at different random addresses each time, so their locations can't be known in advance.

Address space layout randomization (ASLR) places the stack, heap, memory-mapped regions, shared libraries and (for a position-independent executable) the program image at randomly chosen, alignment-respecting base addresses at each load or boot, so an address learned from one run or machine doesn't hold on another.

Examples

  • Printing &main from a position-independent executable gives a different address on each run.

See also

position-independent executable shared library heap address space
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