Search results
Results from the WOW.Com Content Network
In a language with free pointers or non-checked array writes (such as in C), the mixing of control flow data which affects the execution of code (the return addresses or the saved frame pointers) and simple program data (parameters or return values) in a call stack is a security risk, and is possibly exploitable through stack buffer overflows ...
The called function writes the return value to this address. Stack aligned on 16-byte boundary due to a bug. cdecl: Microsoft: RTL (C) Caller: When returning struct/class, Plain old data (POD) return values 32 bits or smaller are in the EAX register; POD return values 33–64 bits in size are returned via the EAX:EDX registers.
The return address is saved by the calling routine, today usually on the process's call stack or in a register. Return statements in many programming languages allow a function to specify a return value to be passed back to the code that called the function.
In particular, subroutines that call other subroutines must save the return address in the link register r14 to the stack before calling those other subroutines. However, such subroutines do not need to return that value to r14—they merely need to load that value into r15, the program counter, to return.
They are then both popped on return from the function call – if they do not match, then the stack is assumed to be corrupted, and a #CP exception is issued. The shadow stack is additionally required to be stored in specially marked memory pages which cannot be modified by normal memory store instructions. INCSSPD r32: F3 0F AE /5
The stack segment register (SS) is usually used to store information about the memory segment that stores the call stack of currently executed program. SP points to current stack top. By default, the stack grows downward in memory, so newer values are placed at lower memory addresses. To save a value to the stack, the PUSH instruction
SP (Stack pointer): Points to the top of stack in memory. It is automatically updated during PUSH and POP operations. BP (Base Pointer): Points to the top of the call stack. It is primarily used to access function parameters and local variables within the call stack. SI (Source Index): Used as a pointer to the source in string and memory array ...
A link register (LR for short) is a register which holds the address to return to when a subroutine call completes. This is more efficient than the more traditional scheme of storing return addresses on a call stack, sometimes called a machine stack. The link register does not require the writes and reads of the memory containing the stack ...