Reversing Some C++ Io Operations

In general decompilers are not friendly with c++ let's analyse a simple program to get familiar with it.
Let's implement a simple code that loads a file into a vector and then save the vector with following functions:

• err
• load
• save
• main

Lets identify the typical way in C++ to print to stdout with the operator "<<"

The basic_ostream is initialized writing the word "error" to the cout, and then the operator<< again to add the endl.

The Main function simply calls  "vec = load(filename)"  but the compiler modified it and passed the vector pointer as a parámeter. Then it bulds and prints "loaded  " << size << " users".
And finally saves the vector to /tmp/pwd and print "saved".
Most of the mess is basically the operator "<<" to concat and print values.
Also note that the vectors and strings are automatically deallocated when exit the function.

And here is the code:

Let's take a look to the load function, which iterates the ifs.getline() and push to the vector.
First of all there is a mess on the function definition, __return_storage_ptr is the vector.
the ifstream object ifs is initialized as a basic_ifstream and then operator! checks if it wasn't possible to open the file and in that case calls err()
We see the memset and a loop, getline read a cstr like line from the file, and then is converted to a string before pushing it to the vector. lVar1 is the stack canary value.

In this situations dont obfuscate with the vector pointer vec initialization at the begining, in this case the logic is quite clear.

The function save is a bit more tricky, but it's no more than a vector iteration and ofs writing.
Looping a simple "for (auto s : *vec)" in the decompiler is quite dense, but we can see clearly two write, the second write DAT_0010400b is a "\n"

As we see, save implememtation is quite straightforward.

More articles

1. Hack Website Online Tool
2. Hacking Tools Online
3. Best Hacking Tools 2019
4. Hacker Tools Github
5. Hacking Tools And Software
6. Hacker Tools List
7. Hacker Tools 2020
8. Termux Hacking Tools 2019
9. Hacking Tools For Kali Linux
10. Hack Tools 2019
11. Pentest Tools Website
12. Bluetooth Hacking Tools Kali
13. Hacking Tools Github
14. Hack Apps
15. Hack Tools For Windows
16. Hack Tools For Windows
17. Termux Hacking Tools 2019
18. Hacking Tools Hardware
19. Best Pentesting Tools 2018
20. Pentest Tools For Mac
21. Hacks And Tools
22. Pentest Tools Nmap
23. Hacking Tools Name
24. Hack Tools Pc
25. Hacker Tools Linux
26. Hacking Tools Usb
27. Nsa Hack Tools Download
28. Pentest Tools Apk
29. Hacking Tools For Games
30. Nsa Hack Tools Download
31. Tools Used For Hacking
32. Android Hack Tools Github
33. Pentest Tools Port Scanner
34. Hacking Tools Windows 10
35. Pentest Tools Url Fuzzer
36. Nsa Hacker Tools
37. Game Hacking
38. Pentest Tools Website Vulnerability
39. Hak5 Tools
40. Nsa Hacker Tools
41. Hacker Tools 2020
42. Hack Tool Apk No Root
43. Hacking Apps
44. Hak5 Tools
45. Hack Website Online Tool
46. Pentest Tools List
47. Hack Tools For Windows
48. Pentest Tools Kali Linux
49. Hacking Tools For Mac
50. Pentest Tools Subdomain
51. Install Pentest Tools Ubuntu
52. Hack App
53. What Are Hacking Tools
54. Pentest Reporting Tools
55. Pentest Tools Free
56. World No 1 Hacker Software
57. Wifi Hacker Tools For Windows
58. Hacker Search Tools
59. Github Hacking Tools
60. Hackers Toolbox
61. Pentest Tools Nmap
62. Blackhat Hacker Tools
63. Hacker
64. Hacker Tools 2020
65. Hacking Tools 2019
66. Hacker Tools Online
67. Pentest Tools Bluekeep
68. Pentest Tools Online
69. Pentest Tools List
70. Ethical Hacker Tools
71. World No 1 Hacker Software