[moxyproxy361]

I see A vuln, I can brute force it to get a value, but I don't know how to get a leak from there....

[moxyproxy361]

anyone got any hints ?

Look at the reservation function and specifically how data is written to the file.

[timi123]

Can anyone help with the way, you leak stuff, because you can read only 4 bytes, how can you leak the pie and the canary?

[r3pick]

Can anyone help with the way, you leak stuff, because you can read only 4 bytes, how can you leak the pie and the canary?

Read the man page of Fork syscall carefully, then you will figure out.