Remove Linux kernel version check

Author: bjorn3

README.md

@@ -13,8 +13,7 @@ Suspected vulnerabilities can be reported on our [security page](https://github.
 An [audit of sudo-rs version 0.2.0](docs/audit/audit-report-sudo-rs.pdf) has been performed in August 2023.
 The findings from that audit are addressed in the current version.
 
-Sudo-rs currently is targeted for Linux-based operating systems only; Linux kernel 5.11
-or newer is necessary to run sudo-rs.
+Sudo-rs currently is targeted for FreeBSD and Linux-based operating systems only.
 
 ## Installing sudo-rs
 

src/common/error.rs

@@ -13,7 +13,6 @@ pub enum Error {
         other_user: Option<SudoString>,
     },
     SelfCheck,
-    KernelCheck,
     CommandNotFound(PathBuf),
     InvalidCommand(PathBuf),
     ChDirNotAllowed {
@@ -61,7 +60,6 @@ impl fmt::Display for Error {
             Error::SelfCheck => {
                 f.write_str("sudo must be owned by uid 0 and have the setuid bit set")
             }
-            Error::KernelCheck => f.write_str("sudo-rs needs a Linux kernel newer than v5.11"),
             Error::CommandNotFound(p) => write!(f, "'{}': command not found", p.display()),
             Error::InvalidCommand(p) => write!(f, "'{}': invalid command", p.display()),
             Error::UserNotFound(u) => write!(f, "user '{u}' not found"),

src/sudo/mod.rs

@@ -4,7 +4,6 @@ use crate::common::resolve::CurrentUser;
 use crate::common::Error;
 use crate::log::dev_info;
 use crate::system::interface::UserId;
-use crate::system::kernel::kernel_check;
 use crate::system::timestamp::RecordScope;
 use crate::system::User;
 use crate::system::{time::Duration, timestamp::SessionRecordFile, Process};
@@ -67,7 +66,6 @@ fn sudo_process() -> Result<(), Error> {
     dev_info!("development logs are enabled");
 
     self_check()?;
-    kernel_check()?;
 
     // parse cli options
     match SudoAction::from_env() {

src/system/kernel.rs

@@ -26,8 +26,6 @@ mod audit;
 // generalized traits for when we want to hide implementations
 pub mod interface;
 
-pub mod kernel;
-
 pub mod file;
 
 pub mod time;
@@ -40,6 +38,9 @@ pub mod term;
 
 pub mod wait;
 
+#[cfg(not(any(target_os = "freebsd", target_os = "linux")))]
+compile_error!("sudo-rs only works on Linux and FreeBSD");
+
 pub(crate) fn can_execute<P: AsRef<Path>>(path: P) -> bool {
     let Ok(path) = CString::new(path.as_ref().as_os_str().as_bytes()) else {
         return false;