Directory traversal attacks

[eager plinth]

How should I go about preventing potential directory traversal attacks when using and concatenating user-input paths?
Path::canonicalize only works for files that actually exist, so it can't be used for detecting directory traversal

[clever grotto]

Would using canonicalize then starts_with work

The canonicalize is definitely needed to prevent escape by using a symlink

[eager plinth]

Nah, because canonicalize fails if the path doesn't exist

[clever grotto]

What do you want to do in that case

[eager plinth]

Let's say I'm extracting a zip file or something, to some/directory/

I want to ensure some/directory/{user_input_path} doesn't leave some/directory

[clever grotto]

Oh, so your taking the path to make?

Not a path to read

[eager plinth]

Ya

[clever grotto]

How about concat it with the root then run https://lib.rs/crates/path-clean on it then check it stays in the same root folder with starts with?

[eager plinth]

Yeah, I think that'll do, thank you
I kind of expected the OS to provide some sort of help with this

[clever grotto]

You could setup a fully sandboxed filesystem but that seems like more work than you probably need

[eager plinth]

oh yeah absolutely

plus needs to be portable

[tropic jasper]

https://docs.rs/cap-std/latest/cap_std/ for the non-OS but

bit heavy