*** *** Saved frame pointer Return address Stack structure foobar(char *args) { unsigned int a = 4; unsigned int b = 8; static long c = 1234567890; short buf[4]; strncpy(buf, args, 24); ain(int argc, char *argv[]) { foobar(argv[1]); return 0; ill variable "a" be overwritten by strncpy and will "b" and "c" also be overwritten? Briefly ain. ill saved frame pointer be overwritten? If yes, how many bytes of the saved frame pointer can werwritten? Briefly explain. Il the return address of foobar be overwritten? If yes, how many bytes of it can be written? Briefly explain. Local variables
*** *** Saved frame pointer Return address Stack structure foobar(char *args) { unsigned int a = 4; unsigned int b = 8; static long c = 1234567890; short buf[4]; strncpy(buf, args, 24); ain(int argc, char *argv[]) { foobar(argv[1]); return 0; ill variable "a" be overwritten by strncpy and will "b" and "c" also be overwritten? Briefly ain. ill saved frame pointer be overwritten? If yes, how many bytes of the saved frame pointer can werwritten? Briefly explain. Il the return address of foobar be overwritten? If yes, how many bytes of it can be written? Briefly explain. Local variables
Database System Concepts
7th Edition
ISBN:9780078022159
Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Chapter1: Introduction
Section: Chapter Questions
Problem 1PE
Related questions
Question
P1
![Q5) Consider the following program loaded to a 32-bit x86 architecture. Suppose the stack frame
is with space allocated only for the variables shown, and there is no memory gap between the
local variable and saved frame pointer. Assume the user input is sufficiently long.
Local variables
Saved frame pointer
Return address
Stack structure
void foobar(char *args) {
unsigned int a = 4;
unsigned int b = 8;
static long c = 1234567890;
short buf[4];
strncpy(buf, args, 24);
}
int main(int argc, char *argv[]) {
foobar(argv[1]);
return 0;
}
a) Will variable "a" be overwritten by strncpy and will "b" and "c" also be overwritten? Briefly
explain.
b) Will saved frame pointer be overwritten? If yes, how many bytes of the saved frame pointer can
be overwritten? Briefly explain.
c) Will the return address of foobar be overwritten? If yes, how many bytes of it can be
overwritten? Briefly explain.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fb950d5ef-686f-40df-b66b-7648f67c6062%2F6001bc3e-383c-47d0-892f-90273c67a41e%2F2fpdhdf_processed.png&w=3840&q=75)
Transcribed Image Text:Q5) Consider the following program loaded to a 32-bit x86 architecture. Suppose the stack frame
is with space allocated only for the variables shown, and there is no memory gap between the
local variable and saved frame pointer. Assume the user input is sufficiently long.
Local variables
Saved frame pointer
Return address
Stack structure
void foobar(char *args) {
unsigned int a = 4;
unsigned int b = 8;
static long c = 1234567890;
short buf[4];
strncpy(buf, args, 24);
}
int main(int argc, char *argv[]) {
foobar(argv[1]);
return 0;
}
a) Will variable "a" be overwritten by strncpy and will "b" and "c" also be overwritten? Briefly
explain.
b) Will saved frame pointer be overwritten? If yes, how many bytes of the saved frame pointer can
be overwritten? Briefly explain.
c) Will the return address of foobar be overwritten? If yes, how many bytes of it can be
overwritten? Briefly explain.
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