chroot: improve support of --skip-chdir

src/uu/chroot/src/chroot.rs

@@ -16,7 +16,8 @@ use std::io::Error;
 use std::os::unix::prelude::OsStrExt;
 use std::path::Path;
 use std::process;
-use uucore::error::{set_exit_code, UClapError, UResult};
+use uucore::error::{set_exit_code, UClapError, UResult, UUsageError};
+use uucore::fs::{canonicalize, MissingHandling, ResolveMode};
 use uucore::libc::{self, chroot, setgid, setgroups, setuid};
 use uucore::{entries, format_usage};
 
@@ -48,6 +49,20 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
  None => return Err(ChrootError::MissingNewRoot.into()),
  };
 
+ let skip_chdir = matches.contains_id(options::SKIP_CHDIR);
+ // We are resolving the path in case it is a symlink or /. or /../
+ if skip_chdir
+ && canonicalize(newroot, MissingHandling::Normal, ResolveMode::Logical)
+ .unwrap()
+ .to_str()
+ != Some("/")
+ {
+ return Err(UUsageError::new(
+ 125,
+ "option --skip-chdir only permitted if NEWROOT is old '/'",
+ ));
+ }
+
  if !newroot.is_dir() {
  return Err(ChrootError::NoSuchDirectory(format!("{}", newroot.display())).into());
  }

tests/by-util/test_chroot.rs

@@ -1,4 +1,4 @@
-// spell-checker:ignore (words) araba newroot userspec chdir pwd's
+// spell-checker:ignore (words) araba newroot userspec chdir pwd's isroot
 
 use crate::common::util::*;
 
@@ -146,21 +146,36 @@ fn test_chroot() {
 }
 
 #[test]
-fn test_chroot_skip_chdir() {
- let ts = TestScenario::new(util_name!());
- let at = &ts.fixtures;
+fn test_chroot_skip_chdir_not_root() {
+ let (at, mut ucmd) = at_and_ucmd!();
 
- let dir = "CHROOT_DIR";
+ let dir = "foobar";
  at.mkdir(dir);
- let env_cd = std::env::current_dir().unwrap();
- if let Ok(result) = run_ucmd_as_root(&ts, &[dir, "--skip-chdir", "pwd"]) {
- // Should return the same path
- assert_eq!(
- result.success().no_stderr().stdout_str(),
- env_cd.to_str().unwrap()
- );
- } else {
- print!("Test skipped; requires root user");
+
+ ucmd.arg("--skip-chdir")
+ .arg(dir)
+ .fails()
+ .stderr_contains("chroot: option --skip-chdir only permitted if NEWROOT is old '/'")
+ .code_is(125);
+}
+
+#[test]
+fn test_chroot_skip_chdir() {
+ let ts = TestScenario::new(util_name!());
+ let at = ts.fixtures.clone();
+ let dirs = ["/", "/.", "/..", "isroot"];
+ at.symlink_file("/", "isroot");
+ for dir in dirs {
+ let env_cd = std::env::current_dir().unwrap();
+ if let Ok(result) = run_ucmd_as_root(&ts, &[dir, "--skip-chdir"]) {
+ // Should return the same path
+ assert_eq!(
+ result.success().no_stderr().stdout_str(),
+ env_cd.to_str().unwrap()
+ );
+ } else {
+ print!("Test skipped; requires root user");
+ }
  }
 }