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Get environment variable address
* I'm not the author of this code, and I'm not sure who is.
* There are several variants floating around on the Internet,
* but this is the one I use.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[]) {
char *ptr;
if(argc < 3) {
printf("Usage: %s <environment variable> <target program name>\n", argv[0]);
ptr = getenv(argv[1]); /* get env var location */
ptr += (strlen(argv[0]) - strlen(argv[2]))*2; /* adjust for program name */
printf("%s will be at %p\n", argv[1], ptr);
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manuelbua commented Sep 4, 2015

Credits for this goes to Jon Erickson :)

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yaojingguo commented Nov 8, 2016

The code is from Page 147 and 148 of Hacking: The Art of Exploitation, 2nd Edition .

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tomtastic commented Aug 8, 2020

Also on page 38 and 39 of Hacking: The Art of Exploitation, 1st Edition .

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