AFL++ TCP desocket library

Other desocketing solutions:

• https://github.com/zardus/preeny (desock and desock2)
• https://github.com/fkie-cad/libdesock
• https://github.com/zyingp/desockmulti
• https://github.com/vanhauser-thc/network-emulator

If these desocket solutions fail, then this one will likely easily work for you - alass with slightly lower performance. And it is easy to extend :-)

Why might this solution work when others do not?

What makes this desocket library special is that only only intercepts accept() calls bound to a specified port. Hence any other network stuff the application does is still working as expected.

How to use

AFL_PRELOAD this library and use the following environment variables:

• DESOCK_PORT=8080 - required for intercepting incoming connections for fuzzing - sets the TCP port
• DESOCK_FORK=1 - intercept and prevent forking
• DESOCK_CLOSE_EXIT=1 - call _exit() when the desocketed file descriptor is closed or shutdowned
• DESOCK_DEBUG=1 - print debug information to stderr

** Internals

Currently the library intercepts the following calls:

shutdown
close
fork
accept
accept4
listen
bind
setsockopt
getsockopt
getpeername
getsockname

`