update example

README.md

@@ -51,6 +51,9 @@ ELF Header:
   Class:                             ELF64
   Data:                              2's complement, big endian
 ...
+
+$ objdump -d obfuscated
+objdump: obfuscated: file format not recognized
 ```
 
 ## Architcture obfuscation
@@ -66,6 +69,9 @@ input: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically link
 
 $ file obfuscated
 obfuscated: ELF 32-bit LSB shared object, x86-64, version 1 (SYSV), no program header, no section header
+
+$ objdump -d obfuscated
+objdump: obfuscated: file format not recognized
 ```
 
 ## Section header obfuscation
@@ -152,18 +158,16 @@ As shown below, only the system function is called in the main function as far a
 ```
 $ objdump -d bin/res_got
 ...
-00000000004011d2 <main>:
-  4011d2:       f3 0f 1e fa             endbr64
-  4011d6:       55                      push   %rbp
-  4011d7:       48 89 e5                mov    %rsp,%rbp
-  4011da:       48 83 ec 10             sub    $0x10,%rsp
-  4011de:       48 8d 05 36 0e 00 00    lea    0xe36(%rip),%rax        # 40201b <_IO_stdin_used+0x1b>
-  4011e5:       48 89 c7                mov    %rax,%rdi
-  4011e8:       e8 73 fe ff ff          call   401060 <system@plt>
-  4011ed:       89 45 fc                mov    %eax,-0x4(%rbp)
-  4011f0:       b8 00 00 00 00          mov    $0x0,%eax
-  4011f5:       c9                      leave
-  4011f6:       c3                      ret
+00000000004011e1 <main>:
+  4011e1:       f3 0f 1e fa             endbr64
+  4011e5:       55                      push   %rbp
+  4011e6:       48 89 e5                mov    %rsp,%rbp
+  4011e9:       48 8d 05 2b 0e 00 00    lea    0xe2b(%rip),%rax        # 40201b <_IO_stdin_used+0x1b>
+  4011f0:       48 89 c7                mov    %rax,%rdi
+  4011f3:       e8 68 fe ff ff          call   401060 <system@plt>
+  4011f8:       b8 00 00 00 00          mov    $0x0,%eax
+  4011fd:       5d                      pop    %rbp
+  4011fe:       c3                      ret
 ...
 ```
 

bin/got.c

@@ -1,14 +1,15 @@
 // gcc got.c -no-pie -o got
-#include<stdio.h>
-#include<stdlib.h>
+#include <stdio.h>
+#include <stdlib.h>
 
 int secret(char* s) {
-    if (s[0] == 's' && s[1] == 'e' && s[2] == 'c' && s[3] == 'r' && s[4] == 'e' && s[5] == 't') {
-        puts("secret function called");
+    if (s[0] == 's' && s[1] == 'e' && s[2] == 'c' && s[3] == 'r' && s[4] == 'e' && s[5] == 't' && s[6] == '?') {
+        printf("secret function called\n");
     }
+
     return 0;
 }
 
 int main() {
-    int x=system("secret");
+    system("secret?\n");
 }

src/obfus.rs

@@ -1,4 +1,5 @@
-use std::io::prelude::*;
+use std::io::Read as _;
+use std::io::Write as _;
 
 pub const HEADER_MAGIC: [u8; 4] = [0x7f, 0x45, 0x4c, 0x46];
 
@@ -224,7 +225,7 @@ impl Obfuscator {
         Ok(())
     }
 
-    fn get_dyn_func_id(&self, function: &str) -> crate::error::Result<u64> {
+    fn get_dyn_func_idx(&self, function: &str) -> crate::error::Result<u64> {
         let idx = self.dyn_strings.find(function).unwrap();
         let (section_addr, section_size, entry_size, _) = self.get_section(".dynsym").unwrap();
 
@@ -280,7 +281,7 @@ impl Obfuscator {
             ));
         }
 
-        let dyn_func = self.get_dyn_func_id(target_function_name)?;
+        let dyn_func = self.get_dyn_func_idx(target_function_name)?;
 
         if self.is_64bit() {
             let (section_addr, section_size, entry_size, _) =