[fix] raise swhkd privileges right after reading config

[ajanon]

As a fix for CVE-2022-27814, root privileges are dropped to the calling user when (re)loading the config file. Privileges were sometimes dropped but never raised again, which caused crashes when sending SIGHUP to swhkd multiple times in a row.

This now always raises privileges after successfully reading the config file.
Fixes #155.

[Shinyzenith]

@EdenQwQ Hello dear, would you mind reviewing this?

[Shinyzenith]

So my only concern is that we never drop the privileges in this patch after raising them.

[ajanon]

Privileges are dropped right at the beginning of the load_config closure:

swhkd/swhkd/src/daemon.rs

Lines 72 to 74 in 022466e

	let load_config = || {
	// Drop privileges to the invoking user.
	perms::drop_privileges(invoking_uid);

With this PR the daemon has full privileges, except while loading the config. If you want to restrict it further, I can try to implement the fix for SIGHUP another way.

[Shinyzenith]

Privileges are dropped right at the beginning of the load_config closure:

swhkd/swhkd/src/daemon.rs

Lines 72 to 74 in 022466e

	let load_config = || {
	// Drop privileges to the invoking user.
	perms::drop_privileges(invoking_uid);

With this PR the daemon has full privileges, except while loading the config. If you want to restrict it further, I can try to implement the fix for SIGHUP another way.

This looks good enough! I'll just perform some security tests on my end once I get the time and merge! ❤️

[Shinyzenith]

To [email protected]:waycrate/swhkd
6b24df8..36281fe main -> main