remove libc calls, get less bugs

Author: squell

src/common/resolve.rs

@@ -210,7 +210,7 @@ pub(crate) fn resolve_path(command: &Path, path: &str) -> Option<PathBuf> {
     // replaced, or passed unchanged to the program that sudo executes.
 
     path.split(':')
-        .map(PathBuf::from)
+        .map(Path::new)
         // ignore all relative paths ("", "." or "./")
         .filter(|path| path.is_absolute())
         // construct a possible executable absolute path candidate

src/sudoers/mod.rs

@@ -13,11 +13,11 @@ use std::collections::{HashMap, HashSet};
 use std::io;
 use std::path::{Path, PathBuf};
 
-use crate::common::resolve::resolve_path;
+use crate::common::resolve::{is_valid_executable, resolve_path};
 use crate::defaults;
 use crate::log::auth_warn;
+use crate::system;
 use crate::system::interface::{GroupId, UnixGroup, UnixUser, UserId};
-use crate::system::{self, can_execute};
 use ast::*;
 use tokens::*;
 
@@ -317,7 +317,7 @@ fn select_editor(settings: &Settings, trusted_env: bool) -> PathBuf {
         if let Some(editor) = std::env::var_os(key) {
             let editor = PathBuf::from(editor);
 
-            let editor = if can_execute(&editor) {
+            let editor = if is_valid_executable(&editor) {
                 editor
             } else if let Some(editor) = resolve_path(
                 &editor,
@@ -337,9 +337,9 @@ fn select_editor(settings: &Settings, trusted_env: bool) -> PathBuf {
     // no acceptable editor found in environment, fallback on config
 
     for editor in blessed_editors.split(':') {
-        let editor = Path::new(editor);
-        if can_execute(editor) {
-            return editor.to_owned();
+        let editor = PathBuf::from(editor);
+        if is_valid_executable(&editor) {
+            return editor;
         }
     }
 

src/system/mod.rs

@@ -2,12 +2,12 @@
 #[cfg(target_os = "linux")]
 use std::str::FromStr;
 use std::{
-    ffi::{c_int, c_uint, CStr, CString},
+    ffi::{c_int, c_uint, CStr},
     fmt, fs, io,
     mem::MaybeUninit,
     ops,
-    os::unix::{self, prelude::OsStrExt},
-    path::{Path, PathBuf},
+    os::unix,
+    path::PathBuf,
 };
 
 use crate::{
@@ -41,15 +41,6 @@ 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;
-    };
-
-    // SAFETY: we are passing a proper pointer to access
-    unsafe { libc::access(path.as_ptr(), libc::X_OK) == 0 }
-}
-
 pub(crate) fn _exit(status: libc::c_int) -> ! {
     // SAFETY: this function is safe to call
     unsafe { libc::_exit(status) }

test-framework/sudo-compliance-tests/src/visudo/sudoers/editor.rs

@@ -27,7 +27,6 @@ echo '{expected}' >> {LOGS_PATH}"
 }
 
 #[test]
-#[ignore]
 fn fallback() {
     let expected = "configured editor was called";
     let editor_path = "/usr/bin/my-editor";