The first `etc` passthrough file is the `/etc/hostname`. Gramine reads
the option to global PAL state, and LibOS uses it to create a pseudo file
with its content. Gramine sanitizes hostname. It requires that it is a valid
domain. This is a difference from Linux, as Linux accepts any hostname value.
That said, Linux doesn't assume that the root user tries to exploit it through
hostname, and Gramine should.

Gramine uses pseudofs for `etc` passthrough.

Signed-off-by: Mariusz Zaborski <[email protected]>

!TODO use this commit message:

[LibOS,PAL,Docs] Introduce etc passthrough (currently only 'hostname')

The first `etc` passthrough file is the `/etc/hostname`. Gramine reads
the host file to global PAL state, and LibOS uses it to create a pseudo file
with its content. Gramine sanitizes hostname. It requires that it is a valid
domain. This is a difference from Linux, as Linux accepts any hostname value.
That said, Linux doesn't assume that the root user tries to exploit it through
hostname, and Gramine should.

Gramine uses pseudofs for `etc` passthrough.

Signed-off-by: Mariusz Zaborski <[email protected]>

Signed-off-by: Mariusz Zaborski <[email protected]>

!TODO use this commit message:

[LibOS,PAL,Docs] Introduce `etc` emulation (currently only 'hostname')

Gramine obtains information from a host, sanitizes it, and stores it in
the global PAL state. Later, LibOS uses it to create a pseudo file
(using pseudofs filesystem).

The difference between Linux and Gramine is that Gramine expected
the hostname to be a valid domain - as we assume the host is untrusted.
In the case of Linux, it doesn't presume that the root user
tries to exploit it through a malicious hostname.

Signed-off-by: Mariusz Zaborski <[email protected]>