The code above is in charge of moving and doing some magic on the user’s
arguments.
Can you spot a bug in it (there may be more than one)?
If you can, describe them as much as you can, while including:
• What is the bug?
• Is it a vulnerability?
• If so, is it exploitable with modern mitigations (ASLR, NX/DEP/R^X and
etc.)?
• If so, how would you try to exploit it?
• How would you fix it?
————————
I think either the task isn't defined well enough or I'm too noob to find the vulnerability

A very weird task

that's more like a developer's task than a security one

since there's no way to actually exploit any bug in 'beforefix'

Assuming you fixed the free issue (no double free+ not trying to free an offset from the original addr returned from malloc)
you can still enter argv[1] string longer than 2^8 chars.... and then memcpy suppose to copy strlen(argv[1]) to the heap memory (where malloc allocated much smaller memory due to value overflow).
Assuming this won't crash- I'll need to inspect the heap memory

heap and stack are very far from each other; also the kind of overflow seen here (malloc one chunk + write beyond its boundary) won't even crash

ахренеть

а что они сделали с кучей
?

все, куча не эксплуатабельна?

а можно еще раз для тех, кто в танке (ядре)

как тоже самое сделать в qemumode

что это такое?

так ну допустим

а шо дальше?

шо если у приложения нету юзеринпута?

шо если