rustc/debian/patches/u-Fix-CVE-2022-21658-for-UNIX-like.patch

From a03c7b755b54e09a3e274974a63c8d0ac32254d7 Mon Sep 17 00:00:00 2001
From: Hans Kratz <hans@appfour.com>
Date: Mon, 17 Jan 2022 09:45:46 +0100
Subject: [PATCH 2/4] Fix CVE-2022-21658 for UNIX-like

~~

backport to 1.52:
- removed macos/redox impl
- removed ignored test case
- removed no longer needed changes to weak! (which is a v1 macro in
  1.52)
- used RawFd instead of OwnedFd (latter doesn't exist in 1.52)

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 library/std/src/fs/tests.rs      |  70 ++++++++
 library/std/src/sys/unix/fs.rs   | 279 +++++++++++++++++++++++++++++--
 3 files changed, 342 insertions(+), 12 deletions(-)

diff --git a/library/std/src/fs/tests.rs b/library/std/src/fs/tests.rs
index 9a8f1e44f1f..4d1959258be 100644
--- a/library/std/src/fs/tests.rs
+++ b/library/std/src/fs/tests.rs
@@ -4,8 +4,10 @@
 use crate::io::{ErrorKind, SeekFrom};
 use crate::path::Path;
 use crate::str;
+use crate::sync::Arc;
 use crate::sys_common::io::test::{tmpdir, TempDir};
 use crate::thread;
+use crate::time::{Duration, Instant};
 
 use rand::{rngs::StdRng, RngCore, SeedableRng};
 
@@ -588,6 +590,21 @@ fn recursive_rmdir_of_symlink() {
 }
 
 #[test]
+fn recursive_rmdir_of_file_fails() {
+    // test we do not delete a directly specified file.
+    let tmpdir = tmpdir();
+    let canary = tmpdir.join("do_not_delete");
+    check!(check!(File::create(&canary)).write(b"foo"));
+    let result = fs::remove_dir_all(&canary);
+    #[cfg(unix)]
+    error!(result, "Not a directory");
+    #[cfg(windows)]
+    error!(result, 267); // ERROR_DIRECTORY - The directory name is invalid.
+    assert!(result.is_err());
+    assert!(canary.exists());
+}
+
+#[test]
 // only Windows makes a distinction between file and directory symlinks.
 #[cfg(windows)]
 fn recursive_rmdir_of_file_symlink() {
 #[test]
 fn unicode_path_is_dir() {
     assert!(Path::new(".").is_dir());
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index a4fff9b2e64..a150d1a9aac 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -48,8 +48,6 @@ use libc::{
     dirent64, fstat64, ftruncate64, lseek64, lstat64, off64_t, open64, readdir64_r, stat64,
 };
 
-pub use crate::sys_common::fs::remove_dir_all;
-
 pub struct File(FileDesc);
 
 // FIXME: This should be available on Linux with all `target_env`.
@@ -212,7 +210,7 @@ pub struct DirEntry {
         target_os = "fuchsia",
         target_os = "redox"
     ))]
-    name: Box<[u8]>,
+    name: CString,
 }
 
 #[derive(Clone, Debug)]
@@ -439,8 +437,6 @@ impl Iterator for ReadDir {
         target_os = "illumos"
     ))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
-        use crate::slice;
-
         unsafe {
             loop {
                 // Although readdir_r(3) would be a correct function to use here because
@@ -458,14 +454,10 @@ impl Iterator for ReadDir {
                     };
                 }
 
-                let name = (*entry_ptr).d_name.as_ptr();
-                let namelen = libc::strlen(name) as usize;
-
                 let ret = DirEntry {
                     entry: *entry_ptr,
-                    name: slice::from_raw_parts(name as *const u8, namelen as usize)
-                        .to_owned()
-                        .into_boxed_slice(),
+                    // d_name is guaranteed to be null-terminated.
+                    name: CStr::from_ptr((*entry_ptr).d_name.as_ptr()).to_owned(),
                     dir: Arc::clone(&self.inner),
                 };
                 if ret.name_bytes() != b"." && ret.name_bytes() != b".." {
@@ -645,7 +637,26 @@ impl DirEntry {
         target_os = "redox"
     ))]
     fn name_bytes(&self) -> &[u8] {
-        &*self.name
+        self.name.as_bytes()
+    }
+
+    #[cfg(not(any(
+        target_os = "solaris",
+        target_os = "illumos",
+        target_os = "fuchsia",
+        target_os = "redox"
+    )))]
+    fn name_cstr(&self) -> &CStr {
+        unsafe { CStr::from_ptr(self.entry.d_name.as_ptr()) }
+    }
+    #[cfg(any(
+        target_os = "solaris",
+        target_os = "illumos",
+        target_os = "fuchsia",
+        target_os = "redox"
+    ))]
+    fn name_cstr(&self) -> &CStr {
+        &self.name
     }
 }
 
@@ -1330,3 +1341,123 @@ pub fn copy(from: &Path, to: &Path) -> i
     })?;
     Ok(bytes_copied as u64)
 }
+
+pub use remove_dir_impl::remove_dir_all;
+
+// Modern implementation using openat(), unlinkat() and fdopendir()
+#[cfg(not(any(all(target_os = "macos", target_arch = "x86_64"), target_os = "redox")))]
+mod remove_dir_impl {
+    use super::{cstr, lstat, Dir, InnerReadDir, ReadDir};
+    use crate::ffi::CStr;
+    use crate::io;
+    use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
+    use crate::os::unix::prelude::RawFd;
+    use crate::path::{Path, PathBuf};
+    use crate::sync::Arc;
+    use crate::sys::{cvt, cvt_r};
+    use libc::{fdopendir, openat, unlinkat};
+
+    pub fn openat_nofollow_dironly(parent_fd: Option<RawFd>, p: &CStr) -> io::Result<RawFd> {
+        let fd = cvt_r(|| unsafe {
+            openat(
+                parent_fd.unwrap_or(libc::AT_FDCWD),
+                p.as_ptr(),
+                libc::O_CLOEXEC | libc::O_RDONLY | libc::O_NOFOLLOW | libc::O_DIRECTORY,
+            )
+        })?;
+        Ok(fd)
+    }
+
+    fn fdreaddir(dir_fd: RawFd) -> io::Result<(ReadDir, RawFd)> {
+        let ptr = unsafe { fdopendir(dir_fd.as_raw_fd()) };
+        if ptr.is_null() {
+            return Err(io::Error::last_os_error());
+        }
+        let dirp = Dir(ptr);
+        // file descriptor is automatically closed by libc::closedir() now, so give up ownership
+        let new_parent_fd = dir_fd.into_raw_fd();
+        // a valid root is not needed because we do not call any functions involving the full path
+        // of the DirEntrys.
+        let dummy_root = PathBuf::new();
+        Ok((
+            ReadDir {
+                inner: Arc::new(InnerReadDir { dirp, root: dummy_root }),
+                #[cfg(not(any(
+                    target_os = "solaris",
+                    target_os = "illumos",
+                    target_os = "fuchsia",
+                    target_os = "redox",
+                )))]
+                end_of_stream: false,
+            },
+            new_parent_fd,
+        ))
+    }
+
+    fn remove_dir_all_recursive(parent_fd: Option<RawFd>, p: &Path) -> io::Result<()> {
+        let pcstr = cstr(p)?;
+
+        // entry is expected to be a directory, open as such
+        let fd = openat_nofollow_dironly(parent_fd, &pcstr)?;
+
+        // open the directory passing ownership of the fd
+        let (dir, fd) = fdreaddir(fd)?;
+        for child in dir {
+            let child = child?;
+            let child_is_dir = if cfg!(any(
+                target_os = "solaris",
+                target_os = "illumos",
+                target_os = "haiku",
+                target_os = "vxworks"
+            )) {
+                // no d_type in dirent
+                None
+            } else {
+                match child.entry.d_type {
+                    libc::DT_UNKNOWN => None,
+                    libc::DT_DIR => Some(true),
+                    _ => Some(false),
+                }
+            };
+            match child_is_dir {
+                Some(true) => {
+                    remove_dir_all_recursive(Some(fd), Path::new(&child.file_name()))?;
+                }
+                Some(false) => {
+                    cvt(unsafe { unlinkat(fd, child.name_cstr().as_ptr(), 0) })?;
+                }
+                None => match cvt(unsafe { unlinkat(fd, child.name_cstr().as_ptr(), 0) }) {
+                    // type unknown - try to unlink
+                    Err(err)
+                        if err.raw_os_error() == Some(libc::EISDIR)
+                            || err.raw_os_error() == Some(libc::EPERM) =>
+                    {
+                        // if the file is a directory unlink fails with EISDIR on Linux and EPERM everyhwere else
+                        remove_dir_all_recursive(Some(fd), Path::new(&child.file_name()))?;
+                    }
+                    result => {
+                        result?;
+                    }
+                },
+            }
+        }
+
+        // unlink the directory after removing its contents
+        cvt(unsafe {
+            unlinkat(parent_fd.unwrap_or(libc::AT_FDCWD), pcstr.as_ptr(), libc::AT_REMOVEDIR)
+        })?;
+        Ok(())
+    }
+
+    pub fn remove_dir_all(p: &Path) -> io::Result<()> {
+        // We cannot just call remove_dir_all_recursive() here because that would not delete a passed
+        // symlink. No need to worry about races, because remove_dir_all_recursive() does not recurse
+        // into symlinks.
+        let attr = lstat(p)?;
+        if attr.file_type().is_symlink() {
+            crate::fs::remove_file(p)
+        } else {
+            remove_dir_all_recursive(None, p)
+        }
+    }
+}
-- 
2.32.0