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In computing, the red zone is a fixed-size area in a function's stack frame below (for a push-down stack) the current stack pointer that is reserved and safe to use. It is most commonly used in leaf functions (functions that don't call other functions) for allocating additional stack memory, without moving the stack pointer, which saves an instruction.
A region, also called a zone, arena, area, or memory context, is a collection of allocated objects that can be efficiently reallocated or deallocated all at once. Memory allocators using region-based managements are often called area allocators , and when they work by only "bumping" a single pointer, as bump allocators .
This is also why functions that use alloca are usually prevented from being inlined: [2] should such a function be inlined into a loop, the caller would suffer from an unanticipated growth in stack usage, making an overflow much more likely. Stack-based allocation can also cause minor performance problems: it leads to variable-size stack frames ...
A NOP-sled is the oldest and most widely known technique for exploiting stack buffer overflows. [2] It solves the problem of finding the exact address of the buffer by effectively increasing the size of the target area. To do this, much larger sections of the stack are corrupted with the no-op machine instruction.
Canaries or canary words or stack cookies are known values that are placed between a buffer and control data on the stack to monitor buffer overflows. When the buffer overflows, the first data to be corrupted will usually be the canary, and a failed verification of the canary data will therefore alert of an overflow, which can then be handled, for example, by invalidating the corrupted data.
Stack Overflow is a question-and-answer website for computer programmers. It is the flagship site of the Stack Exchange Network . [ 2 ] [ 3 ] [ 4 ] It was created in 2008 by Jeff Atwood and Joel Spolsky .
Visualization of a software buffer overflow. Data is written into A, but is too large to fit within A, so it overflows into B.. In programming and information security, a buffer overflow or buffer overrun is an anomaly whereby a program writes data to a buffer beyond the buffer's allocated memory, overwriting adjacent memory locations.
Instructions are always fetched from the code segment. Any stack push or pop or any data reference referring to the stack uses the stack segment. All other references to data use the data segment. The extra segment is the default destination for string operations (for example MOVS or CMPS). FS and GS have no hardware-assigned uses.