En hierom was dynamite dus stuk:
[PATCH] Randomisation: mmap randomisation
The patch below randomizes the starting point of the mmap area.
This has the effect that all non-prelinked shared libaries and all bigger
malloc()s will be randomized between various invocations of the binary.
Prelinked binaries get a address-hint from ld.so in their mmap and are thus
exempt from this randomisation, in order to not break the prelink advantage.
The randomisation range is 1 megabyte (this is bigger than the stack
randomisation since the stack randomisation only needs 16 bytes alignment
while the mmap needs page alignment, a 64kb range would not have given enough
entropy to be effective)
En zo fix je dat dus:
#include <stdio.h>
#include <linux/personality.h>
#include <sys/syscall.h>
#include <unistd.h>
#ifndef ADDR_NO_RANDOMIZE
#define ADDR_NO_RANDOMIZE (0x0040000)
#endif
int main(int argc, char* argv[]) {
char buf[21];
int sc_ret;
FILE* fd;
#ifdef FIXMAPS
sc_ret = syscall(SYS_personality,ADDR_NO_RANDOMIZE);
if(!sc_ret) { /* Syscall succeeded, execute ourselves again */
execvp(argv[0],argv);
}
else if(!(sc_ret & ADDR_NO_RANDOMIZE)) { /* Setting personality failed */
perror("Setting personality failed");
exit(1);
}
#endif
fd = fopen("/proc/self/maps", "r");
buf[20] = '';
while(!feof(fd)) {
fread(buf, 1, 20, fd);
fputs(buf,stdout);
}
}
Compileer met gcc -o main main.c en run het meerder malen. De mappings veranderen steeds. Compileer daarna met gcc -o main main.c -DFIXMAPS en je ziet: de mappings blijven hetzelfde. De stack mapping is wel nog steeds stuk, maar die wordt toch op een andere manier teruggezet. Ik heb goede hoop dat dit alle problemen oplost
Best gezellig hoor, van die grote beesten die uit je hand eten - mensen die het zien kijken er alleen nogal verbaasd naar 