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kloader.c
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kloader.c
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/*
* Copyright 2014, winocm. <winocm@icloud.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
/*
* kloader
* Requires iOS 6.x or 7.x. (This version only.)
*
* Remap addresses:
* 0x7fe00000 -> 0x9fe00000 (0x5fe00000) iBSS (jump-to only.)
*
* xcrun -sdk iphoneos clang kloader.c -arch armv7 -framework IOKit -framework CoreFoundation -no-integrated-as \
* -DINLINE_IT_ALL=1 -Wall -o kloader -miphoneos-version-min=6.0; ldid -Stfp0.plist kloader
*/
#include <mach/mach.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <CoreFoundation/CoreFoundation.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <err.h>
#include <signal.h>
typedef mach_port_t io_service_t;
extern mach_port_t kIOMasterPortDefault;
extern mach_port_t IOPMFindPowerManagement(mach_port_t);
extern kern_return_t IOPMSleepSystem(mach_port_t);
/*
* ARM page bits for L1 sections.
*/
#define L1_SHIFT 20 /* log2(1MB) */
#define L1_SECT_PROTO (1 << 1) /* 0b10 */
#define L1_SECT_B_BIT (1 << 2)
#define L1_SECT_C_BIT (1 << 3)
#define L1_SECT_SORDER (0) /* 0b00, not cacheable, strongly ordered. */
#define L1_SECT_SH_DEVICE (L1_SECT_B_BIT)
#define L1_SECT_WT_NWA (L1_SECT_C_BIT)
#define L1_SECT_WB_NWA (L1_SECT_B_BIT | L1_SECT_C_BIT)
#define L1_SECT_S_BIT (1 << 16)
#define L1_SECT_AP_URW (1 << 10) | (1 << 11)
#define L1_SECT_PFN(x) (x & 0xFFF00000)
#define L1_SECT_DEFPROT (L1_SECT_AP_URW)
#define L1_SECT_DEFCACHE (L1_SECT_SORDER)
#define L1_PROTO_TTE(paddr) (L1_SECT_PFN(paddr) | L1_SECT_S_BIT | L1_SECT_DEFPROT | L1_SECT_DEFCACHE | L1_SECT_PROTO)
#define PFN_SHIFT 2
#define TTB_OFFSET(vaddr) ((vaddr >> L1_SHIFT) << PFN_SHIFT)
/*
* RAM physical base begin.
*/
#define S5L8930_PHYS_OFF 0x40000000
#define S5L8940_PHYS_OFF 0x80000000 /* Note: RAM base is identical for 8940-8955. */
uint32_t PHYS_OFF = S5L8930_PHYS_OFF;
/*
* Shadowmap begin and end. 15MB of shadowmap is enough for the kernel.
* We don't need to invalidate unified D/I TLB or any cache lines
* since the kernel is mapped as writethrough memory, and these
* addresses are guaranteed to not be translated.
* (Accesses will cause segmentation faults due to failure on L1 translation.)
*
* Clear the shadowmappings when done owning the kernel.
*
* 0x7ff0'0000 is also below the limit for vm_read and such, so that's also *great*.
* (2048 bytes)
*/
#define SHADOWMAP_BEGIN 0x7f000000
#define SHADOWMAP_END 0x7ff00000
#define SHADOWMAP_GRANULARITY 0x00100000
#define SHADOWMAP_SIZE_BYTES (SHADOWMAP_END - SHADOWMAP_BEGIN)
#define SHADOWMAP_BEGIN_OFF TTB_OFFSET(SHADOWMAP_BEGIN)
#define SHADOWMAP_END_OFF TTB_OFFSET(SHADOWMAP_END)
#define SHADOWMAP_SIZE (SHADOWMAP_END_OFF - SHADOWMAP_BEGIN_OFF)
#define SHADOWMAP_BEGIN_IDX (SHADOWMAP_BEGIN_OFF >> PFN_SHIFT)
#define SHADOWMAP_END_IDX (SHADOWMAP_END_OFF >> PFN_SHIFT)
#define TTB_SIZE 4096
#define DEFAULT_KERNEL_SLIDE 0x80000000
static mach_port_t kernel_task = 0;
static uint32_t ttb_template[TTB_SIZE] = { };
static void *ttb_template_ptr = &ttb_template[0];
static vm_address_t kernel_base = DEFAULT_KERNEL_SLIDE;
typedef struct pmap_partial_t {
uint32_t tte_virt;
uint32_t tte_phys;
/*
* ...
*/
} pmap_partial_t;
/* --- planetbeing patchfinder --- */
static uint32_t bit_range(uint32_t x, int start, int end)
{
x = (x << (31 - start)) >> (31 - start);
x = (x >> end);
return x;
}
static uint32_t ror(uint32_t x, int places)
{
return (x >> places) | (x << (32 - places));
}
static int thumb_expand_imm_c(uint16_t imm12)
{
if (bit_range(imm12, 11, 10) == 0) {
switch (bit_range(imm12, 9, 8)) {
case 0:
return bit_range(imm12, 7, 0);
case 1:
return (bit_range(imm12, 7, 0) << 16) | bit_range(imm12, 7, 0);
case 2:
return (bit_range(imm12, 7, 0) << 24) | (bit_range(imm12, 7, 0) << 8);
case 3:
return (bit_range(imm12, 7, 0) << 24) | (bit_range(imm12, 7, 0) << 16) | (bit_range(imm12, 7, 0) << 8) | bit_range(imm12, 7, 0);
default:
return 0;
}
} else {
uint32_t unrotated_value = 0x80 | bit_range(imm12, 6, 0);
return ror(unrotated_value, bit_range(imm12, 11, 7));
}
}
static int insn_is_32bit(uint16_t * i)
{
return (*i & 0xe000) == 0xe000 && (*i & 0x1800) != 0x0;
}
static int insn_is_bl(uint16_t * i)
{
if ((*i & 0xf800) == 0xf000 && (*(i + 1) & 0xd000) == 0xd000)
return 1;
else if ((*i & 0xf800) == 0xf000 && (*(i + 1) & 0xd001) == 0xc000)
return 1;
else
return 0;
}
static uint32_t insn_bl_imm32(uint16_t * i)
{
uint16_t insn0 = *i;
uint16_t insn1 = *(i + 1);
uint32_t s = (insn0 >> 10) & 1;
uint32_t j1 = (insn1 >> 13) & 1;
uint32_t j2 = (insn1 >> 11) & 1;
uint32_t i1 = ~(j1 ^ s) & 1;
uint32_t i2 = ~(j2 ^ s) & 1;
uint32_t imm10 = insn0 & 0x3ff;
uint32_t imm11 = insn1 & 0x7ff;
uint32_t imm32 = (imm11 << 1) | (imm10 << 12) | (i2 << 22) | (i1 << 23) | (s ? 0xff000000 : 0);
return imm32;
}
static int insn_is_b_conditional(uint16_t * i)
{
return (*i & 0xF000) == 0xD000 && (*i & 0x0F00) != 0x0F00 && (*i & 0x0F00) != 0xE;
}
static int insn_is_b_unconditional(uint16_t * i)
{
if ((*i & 0xF800) == 0xE000)
return 1;
else if ((*i & 0xF800) == 0xF000 && (*(i + 1) & 0xD000) == 9)
return 1;
else
return 0;
}
static int insn_is_ldr_literal(uint16_t * i)
{
return (*i & 0xF800) == 0x4800 || (*i & 0xFF7F) == 0xF85F;
}
static int insn_ldr_literal_rt(uint16_t * i)
{
if ((*i & 0xF800) == 0x4800)
return (*i >> 8) & 7;
else if ((*i & 0xFF7F) == 0xF85F)
return (*(i + 1) >> 12) & 0xF;
else
return 0;
}
static int insn_ldr_literal_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x4800)
return (*i & 0xF) << 2;
else if ((*i & 0xFF7F) == 0xF85F)
return (*(i + 1) & 0xFFF) * (((*i & 0x0800) == 0x0800) ? 1 : -1);
else
return 0;
}
// TODO: More encodings
static int insn_is_ldr_imm(uint16_t * i)
{
uint8_t opA = bit_range(*i, 15, 12);
uint8_t opB = bit_range(*i, 11, 9);
return opA == 6 && (opB & 4) == 4;
}
static int insn_ldr_imm_rt(uint16_t * i)
{
return (*i & 7);
}
static int insn_ldr_imm_rn(uint16_t * i)
{
return ((*i >> 3) & 7);
}
static int insn_ldr_imm_imm(uint16_t * i)
{
return ((*i >> 6) & 0x1F);
}
// TODO: More encodings
static int insn_is_ldrb_imm(uint16_t * i)
{
return (*i & 0xF800) == 0x7800;
}
static int insn_ldrb_imm_rt(uint16_t * i)
{
return (*i & 7);
}
static int insn_ldrb_imm_rn(uint16_t * i)
{
return ((*i >> 3) & 7);
}
static int insn_ldrb_imm_imm(uint16_t * i)
{
return ((*i >> 6) & 0x1F);
}
static int insn_is_ldr_reg(uint16_t * i)
{
if ((*i & 0xFE00) == 0x5800)
return 1;
else if ((*i & 0xFFF0) == 0xF850 && (*(i + 1) & 0x0FC0) == 0x0000)
return 1;
else
return 0;
}
static int insn_ldr_reg_rn(uint16_t * i)
{
if ((*i & 0xFE00) == 0x5800)
return (*i >> 3) & 0x7;
else if ((*i & 0xFFF0) == 0xF850 && (*(i + 1) & 0x0FC0) == 0x0000)
return (*i & 0xF);
else
return 0;
}
int insn_ldr_reg_rt(uint16_t * i)
{
if ((*i & 0xFE00) == 0x5800)
return *i & 0x7;
else if ((*i & 0xFFF0) == 0xF850 && (*(i + 1) & 0x0FC0) == 0x0000)
return (*(i + 1) >> 12) & 0xF;
else
return 0;
}
int insn_ldr_reg_rm(uint16_t * i)
{
if ((*i & 0xFE00) == 0x5800)
return (*i >> 6) & 0x7;
else if ((*i & 0xFFF0) == 0xF850 && (*(i + 1) & 0x0FC0) == 0x0000)
return *(i + 1) & 0xF;
else
return 0;
}
static int insn_ldr_reg_lsl(uint16_t * i)
{
if ((*i & 0xFE00) == 0x5800)
return 0;
else if ((*i & 0xFFF0) == 0xF850 && (*(i + 1) & 0x0FC0) == 0x0000)
return (*(i + 1) >> 4) & 0x3;
else
return 0;
}
static int insn_is_add_reg(uint16_t * i)
{
if ((*i & 0xFE00) == 0x1800)
return 1;
else if ((*i & 0xFF00) == 0x4400)
return 1;
else if ((*i & 0xFFE0) == 0xEB00)
return 1;
else
return 0;
}
static int insn_add_reg_rd(uint16_t * i)
{
if ((*i & 0xFE00) == 0x1800)
return (*i & 7);
else if ((*i & 0xFF00) == 0x4400)
return (*i & 7) | ((*i & 0x80) >> 4);
else if ((*i & 0xFFE0) == 0xEB00)
return (*(i + 1) >> 8) & 0xF;
else
return 0;
}
static int insn_add_reg_rn(uint16_t * i)
{
if ((*i & 0xFE00) == 0x1800)
return ((*i >> 3) & 7);
else if ((*i & 0xFF00) == 0x4400)
return (*i & 7) | ((*i & 0x80) >> 4);
else if ((*i & 0xFFE0) == 0xEB00)
return (*i & 0xF);
else
return 0;
}
static int insn_add_reg_rm(uint16_t * i)
{
if ((*i & 0xFE00) == 0x1800)
return (*i >> 6) & 7;
else if ((*i & 0xFF00) == 0x4400)
return (*i >> 3) & 0xF;
else if ((*i & 0xFFE0) == 0xEB00)
return *(i + 1) & 0xF;
else
return 0;
}
static int insn_is_movt(uint16_t * i)
{
return (*i & 0xFBF0) == 0xF2C0 && (*(i + 1) & 0x8000) == 0;
}
static int insn_movt_rd(uint16_t * i)
{
return (*(i + 1) >> 8) & 0xF;
}
static int insn_movt_imm(uint16_t * i)
{
return ((*i & 0xF) << 12) | ((*i & 0x0400) << 1) | ((*(i + 1) & 0x7000) >> 4) | (*(i + 1) & 0xFF);
}
static int insn_is_mov_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x2000)
return 1;
else if ((*i & 0xFBEF) == 0xF04F && (*(i + 1) & 0x8000) == 0)
return 1;
else if ((*i & 0xFBF0) == 0xF240 && (*(i + 1) & 0x8000) == 0)
return 1;
else
return 0;
}
static int insn_mov_imm_rd(uint16_t * i)
{
if ((*i & 0xF800) == 0x2000)
return (*i >> 8) & 7;
else if ((*i & 0xFBEF) == 0xF04F && (*(i + 1) & 0x8000) == 0)
return (*(i + 1) >> 8) & 0xF;
else if ((*i & 0xFBF0) == 0xF240 && (*(i + 1) & 0x8000) == 0)
return (*(i + 1) >> 8) & 0xF;
else
return 0;
}
static int insn_mov_imm_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x2000)
return *i & 0xF;
else if ((*i & 0xFBEF) == 0xF04F && (*(i + 1) & 0x8000) == 0)
return thumb_expand_imm_c(((*i & 0x0400) << 1) | ((*(i + 1) & 0x7000) >> 4) | (*(i + 1) & 0xFF));
else if ((*i & 0xFBF0) == 0xF240 && (*(i + 1) & 0x8000) == 0)
return ((*i & 0xF) << 12) | ((*i & 0x0400) << 1) | ((*(i + 1) & 0x7000) >> 4) | (*(i + 1) & 0xFF);
else
return 0;
}
static int insn_is_cmp_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x2800)
return 1;
else if ((*i & 0xFBF0) == 0xF1B0 && (*(i + 1) & 0x8F00) == 0x0F00)
return 1;
else
return 0;
}
static int insn_cmp_imm_rn(uint16_t * i)
{
if ((*i & 0xF800) == 0x2800)
return (*i >> 8) & 7;
else if ((*i & 0xFBF0) == 0xF1B0 && (*(i + 1) & 0x8F00) == 0x0F00)
return *i & 0xF;
else
return 0;
}
static int insn_cmp_imm_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x2800)
return *i & 0xFF;
else if ((*i & 0xFBF0) == 0xF1B0 && (*(i + 1) & 0x8F00) == 0x0F00)
return thumb_expand_imm_c(((*i & 0x0400) << 1) | ((*(i + 1) & 0x7000) >> 4) | (*(i + 1) & 0xFF));
else
return 0;
}
static int insn_is_and_imm(uint16_t * i)
{
return (*i & 0xFBE0) == 0xF000 && (*(i + 1) & 0x8000) == 0;
}
static int insn_and_imm_rn(uint16_t * i)
{
return *i & 0xF;
}
static int insn_and_imm_rd(uint16_t * i)
{
return (*(i + 1) >> 8) & 0xF;
}
static int insn_and_imm_imm(uint16_t * i)
{
return thumb_expand_imm_c(((*i & 0x0400) << 1) | ((*(i + 1) & 0x7000) >> 4) | (*(i + 1) & 0xFF));
}
static int insn_is_push(uint16_t * i)
{
if ((*i & 0xFE00) == 0xB400)
return 1;
else if (*i == 0xE92D)
return 1;
else if (*i == 0xF84D && (*(i + 1) & 0x0FFF) == 0x0D04)
return 1;
else
return 0;
}
static int insn_push_registers(uint16_t * i)
{
if ((*i & 0xFE00) == 0xB400)
return (*i & 0x00FF) | ((*i & 0x0100) << 6);
else if (*i == 0xE92D)
return *(i + 1);
else if (*i == 0xF84D && (*(i + 1) & 0x0FFF) == 0x0D04)
return 1 << ((*(i + 1) >> 12) & 0xF);
else
return 0;
}
static int insn_is_preamble_push(uint16_t * i)
{
return insn_is_push(i) && (insn_push_registers(i) & (1 << 14)) != 0;
}
static int insn_is_str_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return 1;
else if ((*i & 0xF800) == 0x9000)
return 1;
else if ((*i & 0xFFF0) == 0xF8C0)
return 1;
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return 1;
else
return 0;
}
static int insn_str_imm_postindexed(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return 1;
else if ((*i & 0xF800) == 0x9000)
return 1;
else if ((*i & 0xFFF0) == 0xF8C0)
return 1;
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return (*(i + 1) >> 10) & 1;
else
return 0;
}
static int insn_str_imm_wback(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return 0;
else if ((*i & 0xF800) == 0x9000)
return 0;
else if ((*i & 0xFFF0) == 0xF8C0)
return 0;
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return (*(i + 1) >> 8) & 1;
else
return 0;
}
static int insn_str_imm_imm(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return (*i & 0x07C0) >> 4;
else if ((*i & 0xF800) == 0x9000)
return (*i & 0xFF) << 2;
else if ((*i & 0xFFF0) == 0xF8C0)
return (*(i + 1) & 0xFFF);
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return (*(i + 1) & 0xFF);
else
return 0;
}
static int insn_str_imm_rt(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return (*i & 7);
else if ((*i & 0xF800) == 0x9000)
return (*i >> 8) & 7;
else if ((*i & 0xFFF0) == 0xF8C0)
return (*(i + 1) >> 12) & 0xF;
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return (*(i + 1) >> 12) & 0xF;
else
return 0;
}
static int insn_str_imm_rn(uint16_t * i)
{
if ((*i & 0xF800) == 0x6000)
return (*i >> 3) & 7;
else if ((*i & 0xF800) == 0x9000)
return 13;
else if ((*i & 0xFFF0) == 0xF8C0)
return (*i & 0xF);
else if ((*i & 0xFFF0) == 0xF840 && (*(i + 1) & 0x0800) == 0x0800)
return (*i & 0xF);
else
return 0;
}
// Given an instruction, search backwards until an instruction is found matching the specified criterion.
static uint16_t *find_last_insn_matching(uint32_t region, uint8_t * kdata, size_t ksize, uint16_t * current_instruction, int (*match_func) (uint16_t *))
{
while ((uintptr_t) current_instruction > (uintptr_t) kdata) {
if (insn_is_32bit(current_instruction - 2) && !insn_is_32bit(current_instruction - 3)) {
current_instruction -= 2;
} else {
--current_instruction;
}
if (match_func(current_instruction)) {
return current_instruction;
}
}
return NULL;
}
// Given an instruction and a register, find the PC-relative address that was stored inside the register by the time the instruction was reached.
static uint32_t find_pc_rel_value(uint32_t region, uint8_t * kdata, size_t ksize, uint16_t * insn, int reg)
{
// Find the last instruction that completely wiped out this register
int found = 0;
uint16_t *current_instruction = insn;
while ((uintptr_t) current_instruction > (uintptr_t) kdata) {
if (insn_is_32bit(current_instruction - 2)) {
current_instruction -= 2;
} else {
--current_instruction;
}
if (insn_is_mov_imm(current_instruction) && insn_mov_imm_rd(current_instruction) == reg) {
found = 1;
break;
}
if (insn_is_ldr_literal(current_instruction) && insn_ldr_literal_rt(current_instruction) == reg) {
found = 1;
break;
}
}
if (!found)
return 0;
// Step through instructions, executing them as a virtual machine, only caring about instructions that affect the target register and are commonly used for PC-relative addressing.
uint32_t value = 0;
while ((uintptr_t) current_instruction < (uintptr_t) insn) {
if (insn_is_mov_imm(current_instruction) && insn_mov_imm_rd(current_instruction) == reg) {
value = insn_mov_imm_imm(current_instruction);
} else if (insn_is_ldr_literal(current_instruction) && insn_ldr_literal_rt(current_instruction) == reg) {
value = *(uint32_t *) (kdata + (((((uintptr_t) current_instruction - (uintptr_t) kdata) + 4) & 0xFFFFFFFC) + insn_ldr_literal_imm(current_instruction)));
} else if (insn_is_movt(current_instruction) && insn_movt_rd(current_instruction) == reg) {
value |= insn_movt_imm(current_instruction) << 16;
} else if (insn_is_add_reg(current_instruction) && insn_add_reg_rd(current_instruction) == reg) {
if (insn_add_reg_rm(current_instruction) != 15 || insn_add_reg_rn(current_instruction) != reg) {
// Can't handle this kind of operation!
return 0;
}
value += ((uintptr_t) current_instruction - (uintptr_t) kdata) + 4;
}
current_instruction += insn_is_32bit(current_instruction) ? 2 : 1;
}
return value;
}
// Find PC-relative references to a certain address (relative to kdata). This is basically a virtual machine that only cares about instructions used in PC-relative addressing, so no branches, etc.
static uint16_t *find_literal_ref(uint32_t region, uint8_t * kdata, size_t ksize, uint16_t * insn, uint32_t address)
{
uint16_t *current_instruction = insn;
uint32_t value[16];
memset(value, 0, sizeof(value));
while ((uintptr_t) current_instruction < (uintptr_t) (kdata + ksize)) {
if (insn_is_mov_imm(current_instruction)) {
value[insn_mov_imm_rd(current_instruction)] = insn_mov_imm_imm(current_instruction);
} else if (insn_is_ldr_literal(current_instruction)) {
uintptr_t literal_address = (uintptr_t) kdata + ((((uintptr_t) current_instruction - (uintptr_t) kdata) + 4) & 0xFFFFFFFC) + insn_ldr_literal_imm(current_instruction);
if (literal_address >= (uintptr_t) kdata && (literal_address + 4) <= ((uintptr_t) kdata + ksize)) {
value[insn_ldr_literal_rt(current_instruction)] = *(uint32_t *) (literal_address);
}
} else if (insn_is_movt(current_instruction)) {
value[insn_movt_rd(current_instruction)] |= insn_movt_imm(current_instruction) << 16;
} else if (insn_is_add_reg(current_instruction)) {
int reg = insn_add_reg_rd(current_instruction);
if (insn_add_reg_rm(current_instruction) == 15 && insn_add_reg_rn(current_instruction) == reg) {
value[reg] += ((uintptr_t) current_instruction - (uintptr_t) kdata) + 4;
if (value[reg] == address) {
return current_instruction;
}
}
}
current_instruction += insn_is_32bit(current_instruction) ? 2 : 1;
}
return NULL;
}
// This points to kernel_pmap. Use that to change the page tables if necessary.
uint32_t find_pmap_location(uint32_t region, uint8_t * kdata, size_t ksize)
{
// Find location of the pmap_map_bd string.
uint8_t *pmap_map_bd = memmem(kdata, ksize, "\"pmap_map_bd\"", sizeof("\"pmap_map_bd\""));
if (!pmap_map_bd)
return 0;
// Find a reference to the pmap_map_bd string. That function also references kernel_pmap
uint16_t *ptr = find_literal_ref(region, kdata, ksize, (uint16_t *) kdata, (uintptr_t) pmap_map_bd - (uintptr_t) kdata);
if (!ptr)
return 0;
// Find the beginning of it (we may have a version that throws panic after the function end).
while (*ptr != 0xB5F0) {
if ((uint8_t *)ptr == kdata)
return 0;
ptr--;
}
// Find the end of it.
const uint8_t search_function_end[] = { 0xF0, 0xBD };
ptr = memmem(ptr, ksize - ((uintptr_t) ptr - (uintptr_t) kdata), search_function_end, sizeof(search_function_end));
if (!ptr)
return 0;
// Find the last BL before the end of it. The third argument to it should be kernel_pmap
uint16_t *bl = find_last_insn_matching(region, kdata, ksize, ptr, insn_is_bl);
if (!bl)
return 0;
// Find the last LDR R2, [R*] before it that's before any branches. If there are branches, then we have a version of the function that assumes kernel_pmap instead of being passed it.
uint16_t *ldr_r2 = NULL;
uint16_t *current_instruction = bl;
while ((uintptr_t) current_instruction > (uintptr_t) kdata) {
if (insn_is_32bit(current_instruction - 2) && !insn_is_32bit(current_instruction - 3)) {
current_instruction -= 2;
} else {
--current_instruction;
}
if (insn_ldr_imm_rt(current_instruction) == 2 && insn_ldr_imm_imm(current_instruction) == 0) {
ldr_r2 = current_instruction;
break;
} else if (insn_is_b_conditional(current_instruction) || insn_is_b_unconditional(current_instruction)) {
break;
}
}
// The function has a third argument, which must be kernel_pmap. Find out its address
if (ldr_r2)
return find_pc_rel_value(region, kdata, ksize, ldr_r2, insn_ldr_imm_rn(ldr_r2));
// The function has no third argument, Follow the BL.
uint32_t imm32 = insn_bl_imm32(bl);
uint32_t target = ((uintptr_t) bl - (uintptr_t) kdata) + 4 + imm32;
if (target > ksize)
return 0;
// Find the first PC-relative reference in this function.
int found = 0;
int rd;
current_instruction = (uint16_t *) (kdata + target);
while ((uintptr_t) current_instruction < (uintptr_t) (kdata + ksize)) {
if (insn_is_add_reg(current_instruction) && insn_add_reg_rm(current_instruction) == 15) {
found = 1;
rd = insn_add_reg_rd(current_instruction);
current_instruction += insn_is_32bit(current_instruction) ? 2 : 1;
break;
}
current_instruction += insn_is_32bit(current_instruction) ? 2 : 1;
}
if (!found)
return 0;
return find_pc_rel_value(region, kdata, ksize, current_instruction, rd);
}
// Function to find the syscall 0 function pointer. Used to modify the syscall table to call our own code.
uint32_t find_syscall0(uint32_t region, uint8_t * kdata, size_t ksize)
{
// Search for the preamble to syscall 1
const uint8_t syscall1_search[] = { 0x90, 0xB5, 0x01, 0xAF, 0x82, 0xB0, 0x09, 0x68, 0x01, 0x24, 0x00, 0x23 };
void *ptr = memmem(kdata, ksize, syscall1_search, sizeof(syscall1_search));
if (!ptr)
return 0;
// Search for a pointer to syscall 1
uint32_t ptr_address = (uintptr_t) ptr - (uintptr_t) kdata + region;
uint32_t function = ptr_address | 1;
void *syscall1_entry = memmem(kdata, ksize, &function, sizeof(function));
if (!syscall1_entry)
return 0;
// Calculate the address of syscall 0 from the address of the syscall 1 entry
return (uintptr_t) syscall1_entry - (uintptr_t) kdata - 0x18;
}
// 0E E0 9F E7 FF FF FF EA C0 00 0C F1
// ldr lr, [pc, lr]
// b +0x0
// cpsid if
uint32_t find_larm_init_tramp(uint32_t region, uint8_t * kdata, size_t ksize)
{
const uint8_t search[] = { 0x0E, 0xE0, 0x9F, 0xE7, 0xFF, 0xFF, 0xFF, 0xEA, 0xC0, 0x00, 0x0C, 0xF1 };
void *ptr = memmem(kdata, ksize, search, sizeof(search));
if (!ptr)
return 0;
return ((uintptr_t) ptr) - ((uintptr_t) kdata);
}
/* --- planetbeing patchfinder --- */
uint32_t phys_addr_remap = 0x5fe00000;
vm_address_t get_kernel_base()
{
kern_return_t ret;
task_t kernel_task;
vm_region_submap_info_data_64_t info;
vm_size_t size;
mach_msg_type_number_t info_count = VM_REGION_SUBMAP_INFO_COUNT_64;
unsigned int depth = 0;
vm_address_t addr = 0x81200000; /* arm64: addr = 0xffffff8000000000 */
ret = task_for_pid(mach_task_self(), 0, &kernel_task);
if (ret != KERN_SUCCESS)
return -1;
while (1) {
ret = vm_region_recurse_64(kernel_task, &addr, &size, &depth, (vm_region_info_t) & info, &info_count);
if (ret != KERN_SUCCESS)
break;
if (size > 1024 * 1024 * 1024) {
/*
* https://code.google.com/p/iphone-dataprotection/
* hax, sometimes on iOS7 kernel starts at +0x200000 in the 1Gb region
*/
pointer_t buf;
mach_msg_type_number_t sz = 0;
addr += 0x200000;
vm_read(kernel_task, addr + 0x1000, 512, &buf, &sz);
if (*((uint32_t *)buf) != 0xfeedface) {
addr -= 0x200000;
vm_read(kernel_task, addr + 0x1000, 512, &buf, &sz);
if (*((uint32_t*)buf) != 0xfeedface) {
break;
}
}
return addr;
}
addr += size;
}
return -1;
}
static void generate_ttb_entries(void)
{
uint32_t vaddr, vaddr_end, paddr, i;
paddr = PHYS_OFF;
vaddr = SHADOWMAP_BEGIN;
vaddr_end = SHADOWMAP_END;
for (i = vaddr; i <= vaddr_end; i += SHADOWMAP_GRANULARITY, paddr += SHADOWMAP_GRANULARITY) {
#if SPURIOUS_DEBUG_OUTPUT
printf("ProtoTTE: 0x%08x for VA 0x%08x -> PA 0x%08x\n", L1_PROTO_TTE(paddr), i, paddr);
#endif
ttb_template[TTB_OFFSET(i) >> PFN_SHIFT] = L1_PROTO_TTE(paddr);
}
/*
* Remap TTE for iBoot load address.
*/
uint32_t ttb_remap_addr_base = 0x7fe00000;
ttb_template[TTB_OFFSET(ttb_remap_addr_base) >> PFN_SHIFT] = L1_PROTO_TTE(phys_addr_remap);
#if SPURIOUS_DEBUG_OUTPUT
printf("remap -> 0x%08x => 0x%08x (TTE: 0x%08x)\n", ttb_remap_addr_base, phys_addr_remap, L1_PROTO_TTE(phys_addr_remap));
printf("TTE offset begin for shadowmap: 0x%08x\n" "TTE offset end for shadowmap: 0x%08x\n" "TTE size: 0x%08x\n", SHADOWMAP_BEGIN_OFF, SHADOWMAP_END_OFF, SHADOWMAP_SIZE);
#endif
printf("New TTEs generated, base address for remap: 0x%08x, physBase: 0x%08x\n", PHYS_OFF, phys_addr_remap);
return;
}
#define DMPSIZE 0xd00000
extern char shellcode_begin[], shellcode_end[];
extern uint32_t larm_init_tramp;
extern uint32_t flush_dcache, invalidate_icache;
extern uint32_t kern_base, kern_tramp_phys;
int main(int argc, char *argv[])
{
uint32_t chunksize = 2048;
struct stat st;
if (argc != 2) {
printf("usage: %s [loadfile]\n" "This will destroy the current running OS instance and fire up the loaded image.\n" "You have been warned.\n", argv[0]);
return -1;
}
if (stat(argv[1], &st) == -1) {
printf("Failed to open %s.\n", argv[1]);
return -1;
}
/*
* Get physbase.
*/
size_t size;
sysctlbyname("kern.version", NULL, &size, NULL, 0);
char *osversion = malloc(size);
if (sysctlbyname("kern.version", osversion, &size, NULL, 0) == -1) {
printf("fail to kern.version sysctl\n");
exit(-1);
}
#if SPURIOUS_DEBUG_OUTPUT
printf("%s\n", osversion);
#endif
if (strcasestr(osversion, "s5l8930x")) {
PHYS_OFF = S5L8930_PHYS_OFF;
phys_addr_remap = 0x5fe00000;
} else if (strcasestr(osversion, "s5l8920x") || strcasestr(osversion, "s5l8922x")) {
PHYS_OFF = S5L8930_PHYS_OFF;
phys_addr_remap = 0x4fe00000;
} else if (strcasestr(osversion, "s5l8940x") || strcasestr(osversion, "s5l8942x") || strcasestr(osversion, "s5l8947x")) {
/*
* All others have the high ram base.
*/
PHYS_OFF = S5L8940_PHYS_OFF;
phys_addr_remap = 0x9fe00000;
} else if (strcasestr(osversion, "s5l8945x")) {
PHYS_OFF = S5L8940_PHYS_OFF;
phys_addr_remap = 0xbfe00000;
} else if (strcasestr(osversion, "s5l8950x") || strcasestr(osversion, "s5l8955x")) {
PHYS_OFF = S5L8940_PHYS_OFF;
phys_addr_remap = 0xbfe00000;
} else {
printf("Bravely assuming you're on an 8940-class device (unrecognized). You are on your own.\n");
/*
* All others have the high ram base.
*/
PHYS_OFF = S5L8940_PHYS_OFF;
phys_addr_remap = 0x9fe00000;
}
/*
* Pedanticness, though doesn't matter, after we quit the entire OS is gone lol
*/
free(osversion);
#if SPURIOUS_DEBUG_OUTPUT
printf("physOff 0x%08x remap 0x%08x\n", PHYS_OFF, phys_addr_remap);
#endif
/*
* get kernel base.
*/
kernel_base = get_kernel_base();
if (kernel_base == (vm_address_t)-1) {
printf("failed to get kernel_baseel base...\n");
return -1;
}
printf("Kernel base is 0x%08x.\n", kernel_base);
/*
* we can now find the kernel pmap.
*/
kern_return_t r = task_for_pid(mach_task_self(), 0, &kernel_task);
if (r != 0) {
printf("task_for_pid failed.\n");
return -1;
}
/*
* kill
*/
vm_address_t addr = kernel_base + 0x1000, e = 0, sz = 0;
uint8_t *p = malloc(DMPSIZE + 0x1000);
pointer_t buf;
if (!p) {
printf("failed to malloc memory for kernel dump...\n");
return -1;
}
while (addr < (kernel_base + DMPSIZE)) {
vm_read(kernel_task, addr, chunksize, &buf, &sz);
if (!buf || sz == 0)
continue;
uint8_t *z = (uint8_t *) buf;
addr += chunksize;
bcopy(z, p + e, chunksize);
e += chunksize;
}
/*
* kernel dumped, now find pmap.
*/
uint32_t kernel_pmap = kernel_base + 0x1000 + find_pmap_location(kernel_base, (uint8_t *) p, DMPSIZE);
printf("kernel pmap is at 0x%08x.\n", kernel_pmap);
/*
* Read for kernel_pmap, dereference it for pmap_store.
*/
vm_read(kernel_task, kernel_pmap, 2048, &buf, &sz);