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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include "box64stack.h"
#include "box64context.h"
#include "elfloader.h"
#include "debug.h"
#include "emu/x64emu_private.h"
#include "emu/x64run_private.h"
#include "auxval.h"
EXPORTDYN
int CalcStackSize(box64context_t *context)
{
printf_log(LOG_DEBUG, "Calc stack size, based on %d elf(s)\n", context->elfsize);
context->stacksz = 8*1024*1024; context->stackalign=16;
for (int i=0; i<context->elfsize; ++i)
CalcStack(context->elfs[i], &context->stacksz, &context->stackalign);
//if (posix_memalign((void**)&context->stack, context->stackalign, context->stacksz)) {
context->stack = mmap(NULL, context->stacksz, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_GROWSDOWN, -1, 0);
if (context->stack==(void*)-1) {
printf_log(LOG_NONE, "Cannot allocate aligned memory (0x%lx/0x%zx) for stack\n", context->stacksz, context->stackalign);
return 1;
}
//memset(context->stack, 0, context->stacksz);
printf_log(LOG_DEBUG, "Stack is @%p size=0x%lx align=0x%zx\n", context->stack, context->stacksz, context->stackalign);
return 0;
}
uint16_t Pop16(x64emu_t *emu)
{
uint16_t* st = ((uint16_t*)(R_RSP));
R_RSP += 2;
return *st;
}
void Push16(x64emu_t *emu, uint16_t v)
{
R_RSP -= 2;
*((uint16_t*)R_RSP) = v;
}
uint32_t Pop32(x64emu_t *emu)
{
uint32_t* st = ((uint32_t*)(R_RSP));
R_RSP += 4;
return *st;
}
void Push32(x64emu_t *emu, uint32_t v)
{
R_RSP -= 4;
*((uint32_t*)R_RSP) = v;
}
uint64_t Pop64(x64emu_t *emu)
{
uint64_t* st = ((uint64_t*)(R_RSP));
R_RSP += 8;
return *st;
}
void Push64(x64emu_t *emu, uint64_t v)
{
R_RSP -= 8;
*((uint64_t*)R_RSP) = v;
}
void PushString(x64emu_t *emu, const char* s)
{
int sz = strlen(s) + 1;
// round to 4 bytes boundary
R_RSP -= sz;
memcpy((void*)R_RSP, s, sz);
}
EXPORTDYN
void SetupInitialStack(x64emu_t *emu)
{
// start with 0
Push(emu, 0);
// push program executed
PushString(emu, emu->context->argv[0]);
uintptr_t p_arg0 = R_RSP;
// push envs
uintptr_t p_envv[emu->context->envc];
for (int i=emu->context->envc-1; i>=0; --i) {
PushString(emu, emu->context->envv[i]);
p_envv[i] = R_RSP;
}
// push args, also, free the argv[] string and point to the one in the main stack
uintptr_t p_argv[emu->context->argc];
for (int i=emu->context->argc-1; i>=0; --i) {
PushString(emu, emu->context->argv[i]);
p_argv[i] = R_RSP;
free(emu->context->argv[i]);
emu->context->argv[i] = (char*)p_argv[i];
}
// align
uintptr_t tmp = (R_RSP)&~(emu->context->stackalign-1);
memset((void*)tmp, 0, R_RSP-tmp);
R_RSP=tmp;
// push some AuxVector stuffs
PushString(emu, "x86_64");
uintptr_t p_x86_64 = R_RSP;
uintptr_t p_random = real_getauxval(25);
if(!p_random) {
for (int i=0; i<4; ++i)
Push(emu, random());
p_random = R_RSP;
}
// align
tmp = (R_RSP)&~(emu->context->stackalign-1);
memset((void*)tmp, 0, R_RSP-tmp);
R_RSP=tmp;
// push the AuxVector themselves
/* Actual sample:
3 0x400040
4 0x38
5 0xb
6 0x1000
7 0x7f7addca6000
8 (nil)
9 0x401040
11 0x3e8
12 0x3e8
13 0x3e8
14 0x3e8
16 0xbfebfbff
15 0x7ffd5074c4c9
17 0x64
23 (nil)
25 0x7ffd5074c4b9
26 (nil)
31 0x7ffd5074efea
33 0x7ffd507e6000
*/
Push(emu, 0); Push(emu, 0); //AT_NULL(0)=0
//Push(emu, ); Push(emu, 3); //AT_PHDR(3)=address of the PH of the executable
//Push(emu, ); Push(emu, 4); //AT_PHENT(4)=size of PH entry
//Push(emu, ); Push(emu, 5); //AT_PHNUM(5)=number of elf headers
Push(emu, box64_pagesize); Push(emu, 6); //AT_PAGESZ(6)
//Push(emu, real_getauxval(7)); Push(emu, 7); //AT_BASE(7)=ld-2.27.so start (in memory)
Push(emu, 0); Push(emu, 8); //AT_FLAGS(8)=0
Push(emu, R_RIP); Push(emu, 9); //AT_ENTRY(9)=entrypoint
Push(emu, real_getauxval(11)); Push(emu, 11); //AT_UID(11)
Push(emu, real_getauxval(12)); Push(emu, 12); //AT_EUID(12)
Push(emu, real_getauxval(13)); Push(emu, 13); //AT_GID(13)
Push(emu, real_getauxval(14)); Push(emu, 14); //AT_EGID(14)
Push(emu, p_x86_64); Push(emu, 15); //AT_PLATFORM(15)=&"x86_64"
// Push HWCAP:
// FPU: 1<<0 ; VME: 1<<1 ; DE : 1<<2 ; PSE: 1<<3 ; TSC: 1<<4 ; MSR: 1<<5 ; PAE: 1<<6 ; MCE: 1<<7
// CX8: 1<<8 ; APIC:1<<9 ; SEP: 1<<11; MTRR:1<<12; PGE: 1<<13; MCA: 1<<14; CMOV:1<<15
// FCMOV:1<<16; ; MMX: 1<<23
// OSFXR:1<<24; XMM: 1<<25;XMM2: 1<<26; AMD3D:1<<31
Push(emu, (1<<0) | (1<<1) | (1<<2) | (1<<3) | (1<<4) | (1<<8) | (1<<15) | (1<<16) | (1<<23) | (1<<25) | (1<<26));
Push(emu, 16); //AT_HWCAP(16)=...
//Push(emu, sysconf(_SC_CLK_TCK)); Push(emu, 17); //AT_CLKTCK(17)=times() frequency
Push(emu, real_getauxval(23)); Push(emu, 23); //AT_SECURE(23)
Push(emu, p_random); Push(emu, 25); //AT_RANDOM(25)=p_random
Push(emu, 0); Push(emu, 26); //AT_HWCAP2(26)=0
Push(emu, p_arg0); Push(emu, 31); //AT_EXECFN(31)=p_arg0
Push(emu, emu->context->vsyscall); Push(emu, 32); //AT_SYSINFO(32)=vsyscall
//Push(emu, 0); Push(emu, 33); //AT_SYSINFO_EHDR(33)=address of vDSO
if(!emu->context->auxval_start) // store auxval start if needed
emu->context->auxval_start = (uintptr_t*)R_RSP;
// push nil / envs / nil / args / argc
Push(emu, 0);
for (int i=emu->context->envc-1; i>=0; --i)
Push(emu, p_envv[i]);
free(emu->context->envv);
emu->context->envv = (char**)R_RSP;
Push(emu, 0);
for (int i=emu->context->argc-1; i>=0; --i)
Push(emu, p_argv[i]);
free(emu->context->argv);
emu->context->argv = (char**)R_RSP;
Push(emu, emu->context->argc);
}
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