Support setting file mode

File mode of writable AuthFsEntry can now be changed. The mode is
maintain privately in authfs, but also pass through to fd_server.

Note that this change only aims to support getting/setting the file
mode. The mode is not currently used for ACL check.

Bug: 205169366
Test: atest AuthFsHostTest
Test: atest ComposHostTestCases
Test: composd_cmd forced-odrefresh
      # exit 80 without ART hack, with permissive SELinux
Change-Id: I2405baedae9ba2be5e84eb84d3228f7be080f8c6
diff --git a/authfs/src/file.rs b/authfs/src/file.rs
index 6353209..9bbf3ef 100644
--- a/authfs/src/file.rs
+++ b/authfs/src/file.rs
@@ -1,6 +1,8 @@
+mod attr;
 mod dir;
 mod remote_file;
 
+pub use attr::Attr;
 pub use dir::{InMemoryDir, RemoteDirEditor};
 pub use remote_file::{RemoteFileEditor, RemoteFileReader, RemoteMerkleTreeReader};
 
diff --git a/authfs/src/file/attr.rs b/authfs/src/file/attr.rs
new file mode 100644
index 0000000..48084aa
--- /dev/null
+++ b/authfs/src/file/attr.rs
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use log::error;
+use nix::sys::stat::{mode_t, Mode, SFlag};
+use std::io;
+
+use super::VirtFdService;
+
+/// Default/assumed mode of files not created by authfs.
+///
+/// For files that are given to authfs as FDs (i.e. not created through authfs), their mode is
+/// unknown (or untrusted) until it is ever set. The default mode is just to make it
+/// readable/writable to VFS. When the mode is set, the value on fd_server is supposed to become
+/// consistent.
+const DEFAULT_FILE_MODE: Mode =
+    Mode::from_bits_truncate(Mode::S_IRUSR.bits() | Mode::S_IWUSR.bits());
+
+/// Default/assumed mode of directories not created by authfs.
+///
+/// See above.
+const DEFAULT_DIR_MODE: Mode = Mode::S_IRWXU;
+
+/// `Attr` maintains the local truth for attributes (e.g. mode and type) while allowing setting the
+/// remote attribute for the file description.
+pub struct Attr {
+    service: VirtFdService,
+    mode: Mode,
+    remote_fd: i32,
+    is_dir: bool,
+}
+
+impl Attr {
+    pub fn new_file(service: VirtFdService, remote_fd: i32) -> Attr {
+        Attr { service, mode: DEFAULT_FILE_MODE, remote_fd, is_dir: false }
+    }
+
+    pub fn new_dir(service: VirtFdService, remote_fd: i32) -> Attr {
+        Attr { service, mode: DEFAULT_DIR_MODE, remote_fd, is_dir: true }
+    }
+
+    pub fn new_file_with_mode(service: VirtFdService, remote_fd: i32, mode: mode_t) -> Attr {
+        Attr { service, mode: Mode::from_bits_truncate(mode), remote_fd, is_dir: false }
+    }
+
+    pub fn new_dir_with_mode(service: VirtFdService, remote_fd: i32, mode: mode_t) -> Attr {
+        Attr { service, mode: Mode::from_bits_truncate(mode), remote_fd, is_dir: true }
+    }
+
+    pub fn mode(&self) -> u32 {
+        self.mode.bits()
+    }
+
+    /// Sets the file mode.
+    ///
+    /// In addition to the actual file mode, `encoded_mode` also contains information of the file
+    /// type.
+    pub fn set_mode(&mut self, encoded_mode: u32) -> io::Result<()> {
+        let new_sflag = SFlag::from_bits_truncate(encoded_mode);
+        let new_mode = Mode::from_bits_truncate(encoded_mode);
+
+        let type_flag = if self.is_dir { SFlag::S_IFDIR } else { SFlag::S_IFREG };
+        if !type_flag.contains(new_sflag) {
+            return Err(io::Error::from_raw_os_error(libc::EINVAL));
+        }
+
+        // Request for update only if changing.
+        if new_mode != self.mode {
+            self.service.chmod(self.remote_fd, new_mode.bits() as i32).map_err(|e| {
+                error!(
+                    "Failed to chmod (fd: {}, mode: {:o}) on fd_server: {:?}",
+                    self.remote_fd, new_mode, e
+                );
+                io::Error::from_raw_os_error(libc::EIO)
+            })?;
+            self.mode = new_mode;
+        }
+        Ok(())
+    }
+}
diff --git a/authfs/src/file/dir.rs b/authfs/src/file/dir.rs
index 2a8f359..7f26fd7 100644
--- a/authfs/src/file/dir.rs
+++ b/authfs/src/file/dir.rs
@@ -15,10 +15,12 @@
  */
 
 use log::warn;
+use nix::sys::stat::Mode;
 use std::collections::{hash_map, HashMap};
 use std::io;
 use std::path::{Path, PathBuf};
 
+use super::attr::Attr;
 use super::remote_file::RemoteFileEditor;
 use super::{validate_basename, VirtFdService, VirtFdServiceStatus};
 use crate::fsverity::VerifiedFileEditor;
@@ -74,37 +76,43 @@
         &mut self,
         basename: &Path,
         inode: Inode,
-    ) -> io::Result<VerifiedFileEditor<RemoteFileEditor>> {
-        self.validate_argument(basename)?;
-
+        mode: libc::mode_t,
+    ) -> io::Result<(VerifiedFileEditor<RemoteFileEditor>, Attr)> {
+        let mode = self.validate_arguments(basename, mode)?;
         let basename_str =
             basename.to_str().ok_or_else(|| io::Error::from_raw_os_error(libc::EINVAL))?;
         let new_fd = self
             .service
-            .createFileInDirectory(self.remote_dir_fd, basename_str)
+            .createFileInDirectory(self.remote_dir_fd, basename_str, mode as i32)
             .map_err(into_io_error)?;
 
         let new_remote_file =
             VerifiedFileEditor::new(RemoteFileEditor::new(self.service.clone(), new_fd));
         self.entries.insert(basename.to_path_buf(), DirEntry { inode, is_dir: false });
-        Ok(new_remote_file)
+        let new_attr = Attr::new_file_with_mode(self.service.clone(), new_fd, mode);
+        Ok((new_remote_file, new_attr))
     }
 
     /// Creates a remote directory named `basename` with corresponding `inode` at the current
     /// directory.
-    pub fn mkdir(&mut self, basename: &Path, inode: Inode) -> io::Result<RemoteDirEditor> {
-        self.validate_argument(basename)?;
-
+    pub fn mkdir(
+        &mut self,
+        basename: &Path,
+        inode: Inode,
+        mode: libc::mode_t,
+    ) -> io::Result<(RemoteDirEditor, Attr)> {
+        let mode = self.validate_arguments(basename, mode)?;
         let basename_str =
             basename.to_str().ok_or_else(|| io::Error::from_raw_os_error(libc::EINVAL))?;
         let new_fd = self
             .service
-            .createDirectoryInDirectory(self.remote_dir_fd, basename_str)
+            .createDirectoryInDirectory(self.remote_dir_fd, basename_str, mode as i32)
             .map_err(into_io_error)?;
 
         let new_remote_dir = RemoteDirEditor::new(self.service.clone(), new_fd);
         self.entries.insert(basename.to_path_buf(), DirEntry { inode, is_dir: true });
-        Ok(new_remote_dir)
+        let new_attr = Attr::new_dir_with_mode(self.service.clone(), new_fd, mode);
+        Ok((new_remote_dir, new_attr))
     }
 
     /// Deletes a file
@@ -167,17 +175,19 @@
         }
     }
 
-    fn validate_argument(&self, basename: &Path) -> io::Result<()> {
+    fn validate_arguments(&self, basename: &Path, mode: u32) -> io::Result<u32> {
         // Kernel should only give us a basename.
         debug_assert!(validate_basename(basename).is_ok());
 
         if self.entries.contains_key(basename) {
-            Err(io::Error::from_raw_os_error(libc::EEXIST))
-        } else if self.entries.len() >= MAX_ENTRIES.into() {
-            Err(io::Error::from_raw_os_error(libc::EMLINK))
-        } else {
-            Ok(())
+            return Err(io::Error::from_raw_os_error(libc::EEXIST));
         }
+
+        if self.entries.len() >= MAX_ENTRIES.into() {
+            return Err(io::Error::from_raw_os_error(libc::EMLINK));
+        }
+
+        Ok(Mode::from_bits_truncate(mode).bits())
     }
 }
 
diff --git a/authfs/src/fusefs.rs b/authfs/src/fusefs.rs
index 17a368f..85a8371 100644
--- a/authfs/src/fusefs.rs
+++ b/authfs/src/fusefs.rs
@@ -37,8 +37,8 @@
 
 use crate::common::{divide_roundup, ChunkedSizeIter, CHUNK_SIZE};
 use crate::file::{
-    validate_basename, InMemoryDir, RandomWrite, ReadByChunk, RemoteDirEditor, RemoteFileEditor,
-    RemoteFileReader, RemoteMerkleTreeReader,
+    validate_basename, Attr, InMemoryDir, RandomWrite, ReadByChunk, RemoteDirEditor,
+    RemoteFileEditor, RemoteFileReader, RemoteMerkleTreeReader,
 };
 use crate::fsstat::RemoteFsStatsReader;
 use crate::fsverity::{VerifiedFileEditor, VerifiedFileReader};
@@ -66,16 +66,16 @@
     UnverifiedReadonly { reader: RemoteFileReader, file_size: u64 },
     /// A file type that is initially empty, and the content is stored on a remote server. File
     /// integrity is guaranteed with private Merkle tree.
-    VerifiedNew { editor: VerifiedFileEditor<RemoteFileEditor> },
+    VerifiedNew { editor: VerifiedFileEditor<RemoteFileEditor>, attr: Attr },
     /// A directory type that is initially empty. One can create new file (`VerifiedNew`) and new
     /// directory (`VerifiedNewDirectory` itself) with integrity guaranteed within the VM.
-    VerifiedNewDirectory { dir: RemoteDirEditor },
+    VerifiedNewDirectory { dir: RemoteDirEditor, attr: Attr },
 }
 
 impl AuthFsEntry {
-    fn expect_empty_writable_directory(&self) -> io::Result<()> {
+    fn expect_empty_deletable_directory(&self) -> io::Result<()> {
         match self {
-            AuthFsEntry::VerifiedNewDirectory { dir } => {
+            AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                 if dir.number_of_entries() == 0 {
                     Ok(())
                 } else {
@@ -304,7 +304,7 @@
 #[allow(clippy::enum_variant_names)]
 enum AccessMode {
     ReadOnly,
-    ReadWrite,
+    Variable(u32),
 }
 
 fn create_stat(
@@ -317,10 +317,11 @@
 
     st.st_ino = ino;
     st.st_mode = match access_mode {
-        // Until needed, let's just grant the owner access.
-        // TODO(205169366): Implement mode properly.
-        AccessMode::ReadOnly => libc::S_IFREG | libc::S_IRUSR,
-        AccessMode::ReadWrite => libc::S_IFREG | libc::S_IRUSR | libc::S_IWUSR,
+        AccessMode::ReadOnly => {
+            // Until needed, let's just grant the owner access.
+            libc::S_IFREG | libc::S_IRUSR
+        }
+        AccessMode::Variable(mode) => libc::S_IFREG | mode,
     };
     st.st_nlink = 1;
     st.st_uid = 0;
@@ -334,18 +335,22 @@
     Ok(st)
 }
 
-fn create_dir_stat(ino: libc::ino_t, file_number: u16) -> io::Result<libc::stat64> {
+fn create_dir_stat(
+    ino: libc::ino_t,
+    file_number: u16,
+    access_mode: AccessMode,
+) -> io::Result<libc::stat64> {
     // SAFETY: stat64 is a plan C struct without pointer.
     let mut st = unsafe { MaybeUninit::<libc::stat64>::zeroed().assume_init() };
 
     st.st_ino = ino;
-    // TODO(205169366): Implement mode properly.
-    st.st_mode = libc::S_IFDIR
-        | libc::S_IXUSR
-        | libc::S_IWUSR
-        | libc::S_IRUSR
-        | libc::S_IXGRP
-        | libc::S_IXOTH;
+    st.st_mode = match access_mode {
+        AccessMode::ReadOnly => {
+            // Until needed, let's just grant the owner access and search to group and others.
+            libc::S_IFDIR | libc::S_IXUSR | libc::S_IRUSR | libc::S_IXGRP | libc::S_IXOTH
+        }
+        AccessMode::Variable(mode) => libc::S_IFDIR | mode,
+    };
 
     // 2 extra for . and ..
     st.st_nlink = file_number
@@ -431,7 +436,7 @@
                     let path = cstr_to_path(name);
                     dir.lookup_inode(path).ok_or_else(|| io::Error::from_raw_os_error(libc::ENOENT))
                 }
-                AuthFsEntry::VerifiedNewDirectory { dir } => {
+                AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                     let path = cstr_to_path(name);
                     dir.find_inode(path)
                 }
@@ -445,18 +450,20 @@
             |InodeState { entry, handle_ref_count, .. }| {
                 let st = match entry {
                     AuthFsEntry::ReadonlyDirectory { dir } => {
-                        create_dir_stat(inode, dir.number_of_entries())
+                        create_dir_stat(inode, dir.number_of_entries(), AccessMode::ReadOnly)
                     }
                     AuthFsEntry::UnverifiedReadonly { file_size, .. }
                     | AuthFsEntry::VerifiedReadonly { file_size, .. } => {
                         create_stat(inode, *file_size, AccessMode::ReadOnly)
                     }
-                    AuthFsEntry::VerifiedNew { editor } => {
-                        create_stat(inode, editor.size(), AccessMode::ReadWrite)
+                    AuthFsEntry::VerifiedNew { editor, attr, .. } => {
+                        create_stat(inode, editor.size(), AccessMode::Variable(attr.mode()))
                     }
-                    AuthFsEntry::VerifiedNewDirectory { dir } => {
-                        create_dir_stat(inode, dir.number_of_entries())
-                    }
+                    AuthFsEntry::VerifiedNewDirectory { dir, attr } => create_dir_stat(
+                        inode,
+                        dir.number_of_entries(),
+                        AccessMode::Variable(attr.mode()),
+                    ),
                 }?;
                 *handle_ref_count += 1;
                 Ok(st)
@@ -514,18 +521,20 @@
             Ok((
                 match config {
                     AuthFsEntry::ReadonlyDirectory { dir } => {
-                        create_dir_stat(inode, dir.number_of_entries())
+                        create_dir_stat(inode, dir.number_of_entries(), AccessMode::ReadOnly)
                     }
                     AuthFsEntry::UnverifiedReadonly { file_size, .. }
                     | AuthFsEntry::VerifiedReadonly { file_size, .. } => {
                         create_stat(inode, *file_size, AccessMode::ReadOnly)
                     }
-                    AuthFsEntry::VerifiedNew { editor } => {
-                        create_stat(inode, editor.size(), AccessMode::ReadWrite)
+                    AuthFsEntry::VerifiedNew { editor, attr, .. } => {
+                        create_stat(inode, editor.size(), AccessMode::Variable(attr.mode()))
                     }
-                    AuthFsEntry::VerifiedNewDirectory { dir } => {
-                        create_dir_stat(inode, dir.number_of_entries())
-                    }
+                    AuthFsEntry::VerifiedNewDirectory { dir, attr } => create_dir_stat(
+                        inode,
+                        dir.number_of_entries(),
+                        AccessMode::Variable(attr.mode()),
+                    ),
                 }?,
                 DEFAULT_METADATA_TIMEOUT,
             ))
@@ -546,8 +555,8 @@
                     check_access_mode(flags, libc::O_RDONLY)?;
                 }
                 AuthFsEntry::VerifiedNew { .. } => {
-                    // No need to check access modes since all the modes are allowed to the
-                    // read-writable file.
+                    // TODO(victorhsieh): Imeplement ACL check using the attr and ctx. Always allow
+                    // for now.
                 }
                 AuthFsEntry::ReadonlyDirectory { .. }
                 | AuthFsEntry::VerifiedNewDirectory { .. } => {
@@ -566,22 +575,22 @@
         _ctx: Context,
         parent: Self::Inode,
         name: &CStr,
-        _mode: u32,
+        mode: u32,
         _flags: u32,
-        _umask: u32,
+        umask: u32,
     ) -> io::Result<(Entry, Option<Self::Handle>, fuse::sys::OpenOptions)> {
-        // TODO(205169366): Implement mode properly.
         // TODO(205172873): handle O_TRUNC and O_EXCL properly.
         let new_inode = self.create_new_entry_with_ref_count(
             parent,
             name,
             |parent_entry, basename, new_inode| match parent_entry {
-                AuthFsEntry::VerifiedNewDirectory { dir } => {
+                AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                     if dir.has_entry(basename) {
                         return Err(io::Error::from_raw_os_error(libc::EEXIST));
                     }
-                    let new_file = dir.create_file(basename, new_inode)?;
-                    Ok(AuthFsEntry::VerifiedNew { editor: new_file })
+                    let mode = mode & !umask;
+                    let (new_file, new_attr) = dir.create_file(basename, new_inode, mode)?;
+                    Ok(AuthFsEntry::VerifiedNew { editor: new_file, attr: new_attr })
                 }
                 _ => Err(io::Error::from_raw_os_error(libc::EBADF)),
             },
@@ -591,7 +600,7 @@
             Entry {
                 inode: new_inode,
                 generation: 0,
-                attr: create_stat(new_inode, /* file_size */ 0, AccessMode::ReadWrite)?,
+                attr: create_stat(new_inode, /* file_size */ 0, AccessMode::Variable(mode))?,
                 entry_timeout: DEFAULT_METADATA_TIMEOUT,
                 attr_timeout: DEFAULT_METADATA_TIMEOUT,
             },
@@ -620,12 +629,15 @@
                 AuthFsEntry::UnverifiedReadonly { reader, file_size } => {
                     read_chunks(w, reader, *file_size, offset, size)
                 }
-                AuthFsEntry::VerifiedNew { editor } => {
+                AuthFsEntry::VerifiedNew { editor, .. } => {
                     // Note that with FsOptions::WRITEBACK_CACHE, it's possible for the kernel to
                     // request a read even if the file is open with O_WRONLY.
                     read_chunks(w, editor, editor.size(), offset, size)
                 }
-                _ => Err(io::Error::from_raw_os_error(libc::EBADF)),
+                AuthFsEntry::ReadonlyDirectory { .. }
+                | AuthFsEntry::VerifiedNewDirectory { .. } => {
+                    Err(io::Error::from_raw_os_error(libc::EISDIR))
+                }
             }
         })
     }
@@ -643,12 +655,17 @@
         _flags: u32,
     ) -> io::Result<usize> {
         self.handle_inode(&inode, |config| match config {
-            AuthFsEntry::VerifiedNew { editor } => {
+            AuthFsEntry::VerifiedNew { editor, .. } => {
                 let mut buf = vec![0; size as usize];
                 r.read_exact(&mut buf)?;
                 editor.write_at(&buf, offset)
             }
-            _ => Err(io::Error::from_raw_os_error(libc::EBADF)),
+            AuthFsEntry::VerifiedReadonly { .. } | AuthFsEntry::UnverifiedReadonly { .. } => {
+                Err(io::Error::from_raw_os_error(libc::EPERM))
+            }
+            AuthFsEntry::ReadonlyDirectory { .. } | AuthFsEntry::VerifiedNewDirectory { .. } => {
+                Err(io::Error::from_raw_os_error(libc::EISDIR))
+            }
         })
     }
 
@@ -656,55 +673,51 @@
         &self,
         _ctx: Context,
         inode: Inode,
-        attr: libc::stat64,
+        in_attr: libc::stat64,
         _handle: Option<Handle>,
         valid: SetattrValid,
     ) -> io::Result<(libc::stat64, Duration)> {
-        self.handle_inode(&inode, |config| {
-            match config {
-                AuthFsEntry::VerifiedNew { editor } => {
-                    // Initialize the default stat.
-                    let mut new_attr = create_stat(inode, editor.size(), AccessMode::ReadWrite)?;
-                    // `valid` indicates what fields in `attr` are valid. Update to return correctly.
-                    if valid.contains(SetattrValid::SIZE) {
-                        // st_size is i64, but the cast should be safe since kernel should not give a
-                        // negative size.
-                        debug_assert!(attr.st_size >= 0);
-                        new_attr.st_size = attr.st_size;
-                        editor.resize(attr.st_size as u64)?;
-                    }
+        let mut inode_table = self.inode_table.lock().unwrap();
+        handle_inode_mut_locked(&mut inode_table, &inode, |InodeState { entry, .. }| match entry {
+            AuthFsEntry::VerifiedNew { editor, attr } => {
+                check_unsupported_setattr_request(valid)?;
 
-                    if valid.contains(SetattrValid::MODE) {
-                        warn!("Changing st_mode is not currently supported");
-                        return Err(io::Error::from_raw_os_error(libc::ENOSYS));
-                    }
-                    if valid.contains(SetattrValid::UID) {
-                        warn!("Changing st_uid is not currently supported");
-                        return Err(io::Error::from_raw_os_error(libc::ENOSYS));
-                    }
-                    if valid.contains(SetattrValid::GID) {
-                        warn!("Changing st_gid is not currently supported");
-                        return Err(io::Error::from_raw_os_error(libc::ENOSYS));
-                    }
-                    if valid.contains(SetattrValid::CTIME) {
-                        debug!(
-                            "Ignoring ctime change as authfs does not maintain timestamp currently"
-                        );
-                    }
-                    if valid.intersects(SetattrValid::ATIME | SetattrValid::ATIME_NOW) {
-                        debug!(
-                            "Ignoring atime change as authfs does not maintain timestamp currently"
-                        );
-                    }
-                    if valid.intersects(SetattrValid::MTIME | SetattrValid::MTIME_NOW) {
-                        debug!(
-                            "Ignoring mtime change as authfs does not maintain timestamp currently"
-                        );
-                    }
-                    Ok((new_attr, DEFAULT_METADATA_TIMEOUT))
+                // Initialize the default stat.
+                let mut new_attr =
+                    create_stat(inode, editor.size(), AccessMode::Variable(attr.mode()))?;
+                // `valid` indicates what fields in `attr` are valid. Update to return correctly.
+                if valid.contains(SetattrValid::SIZE) {
+                    // st_size is i64, but the cast should be safe since kernel should not give a
+                    // negative size.
+                    debug_assert!(in_attr.st_size >= 0);
+                    new_attr.st_size = in_attr.st_size;
+                    editor.resize(in_attr.st_size as u64)?;
                 }
-                _ => Err(io::Error::from_raw_os_error(libc::EBADF)),
+                if valid.contains(SetattrValid::MODE) {
+                    attr.set_mode(in_attr.st_mode)?;
+                    new_attr.st_mode = in_attr.st_mode;
+                }
+                Ok((new_attr, DEFAULT_METADATA_TIMEOUT))
             }
+            AuthFsEntry::VerifiedNewDirectory { dir, attr } => {
+                check_unsupported_setattr_request(valid)?;
+                if valid.contains(SetattrValid::SIZE) {
+                    return Err(io::Error::from_raw_os_error(libc::EISDIR));
+                }
+
+                // Initialize the default stat.
+                let mut new_attr = create_dir_stat(
+                    inode,
+                    dir.number_of_entries(),
+                    AccessMode::Variable(attr.mode()),
+                )?;
+                if valid.contains(SetattrValid::MODE) {
+                    attr.set_mode(in_attr.st_mode)?;
+                    new_attr.st_mode = in_attr.st_mode;
+                }
+                Ok((new_attr, DEFAULT_METADATA_TIMEOUT))
+            }
+            _ => Err(io::Error::from_raw_os_error(libc::EPERM)),
         })
     }
 
@@ -717,7 +730,7 @@
     ) -> io::Result<GetxattrReply> {
         self.handle_inode(&inode, |config| {
             match config {
-                AuthFsEntry::VerifiedNew { editor } => {
+                AuthFsEntry::VerifiedNew { editor, .. } => {
                     // FUSE ioctl is limited, thus we can't implement fs-verity ioctls without a kernel
                     // change (see b/196635431). Until it's possible, use xattr to expose what we need
                     // as an authfs specific API.
@@ -747,20 +760,20 @@
         _ctx: Context,
         parent: Self::Inode,
         name: &CStr,
-        _mode: u32,
-        _umask: u32,
+        mode: u32,
+        umask: u32,
     ) -> io::Result<Entry> {
-        // TODO(205169366): Implement mode properly.
         let new_inode = self.create_new_entry_with_ref_count(
             parent,
             name,
             |parent_entry, basename, new_inode| match parent_entry {
-                AuthFsEntry::VerifiedNewDirectory { dir } => {
+                AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                     if dir.has_entry(basename) {
                         return Err(io::Error::from_raw_os_error(libc::EEXIST));
                     }
-                    let new_dir = dir.mkdir(basename, new_inode)?;
-                    Ok(AuthFsEntry::VerifiedNewDirectory { dir: new_dir })
+                    let mode = mode & !umask;
+                    let (new_dir, new_attr) = dir.mkdir(basename, new_inode, mode)?;
+                    Ok(AuthFsEntry::VerifiedNewDirectory { dir: new_dir, attr: new_attr })
                 }
                 AuthFsEntry::ReadonlyDirectory { .. } => {
                     Err(io::Error::from_raw_os_error(libc::EACCES))
@@ -772,7 +785,7 @@
         Ok(Entry {
             inode: new_inode,
             generation: 0,
-            attr: create_dir_stat(new_inode, /* file_number */ 0)?,
+            attr: create_dir_stat(new_inode, /* file_number */ 0, AccessMode::Variable(mode))?,
             entry_timeout: DEFAULT_METADATA_TIMEOUT,
             attr_timeout: DEFAULT_METADATA_TIMEOUT,
         })
@@ -784,7 +797,7 @@
             &mut inode_table,
             &parent,
             |InodeState { entry, unlinked, .. }| match entry {
-                AuthFsEntry::VerifiedNewDirectory { dir } => {
+                AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                     let basename: &Path = cstr_to_path(name);
                     // Delete the file from in both the local and remote directories.
                     let _inode = dir.delete_file(basename)?;
@@ -810,11 +823,11 @@
 
         // Check before actual removal, with readonly borrow.
         handle_inode_locked(&inode_table, &parent, |inode_state| match &inode_state.entry {
-            AuthFsEntry::VerifiedNewDirectory { dir } => {
+            AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                 let basename: &Path = cstr_to_path(name);
                 let existing_inode = dir.find_inode(basename)?;
                 handle_inode_locked(&inode_table, &existing_inode, |inode_state| {
-                    inode_state.entry.expect_empty_writable_directory()
+                    inode_state.entry.expect_empty_deletable_directory()
                 })
             }
             AuthFsEntry::ReadonlyDirectory { .. } => {
@@ -829,7 +842,7 @@
             &mut inode_table,
             &parent,
             |InodeState { entry, unlinked, .. }| match entry {
-                AuthFsEntry::VerifiedNewDirectory { dir } => {
+                AuthFsEntry::VerifiedNewDirectory { dir, .. } => {
                     let basename: &Path = cstr_to_path(name);
                     let _inode = dir.force_delete_directory(basename)?;
                     *unlinked = true;
@@ -897,6 +910,27 @@
     }
 }
 
+fn check_unsupported_setattr_request(valid: SetattrValid) -> io::Result<()> {
+    if valid.contains(SetattrValid::UID) {
+        warn!("Changing st_uid is not currently supported");
+        return Err(io::Error::from_raw_os_error(libc::ENOSYS));
+    }
+    if valid.contains(SetattrValid::GID) {
+        warn!("Changing st_gid is not currently supported");
+        return Err(io::Error::from_raw_os_error(libc::ENOSYS));
+    }
+    if valid.intersects(
+        SetattrValid::CTIME
+            | SetattrValid::ATIME
+            | SetattrValid::ATIME_NOW
+            | SetattrValid::MTIME
+            | SetattrValid::MTIME_NOW,
+    ) {
+        debug!("Ignoring ctime/atime/mtime change as authfs does not maintain timestamp currently");
+    }
+    Ok(())
+}
+
 fn cstr_to_path(cstr: &CStr) -> &Path {
     OsStr::from_bytes(cstr.to_bytes()).as_ref()
 }
diff --git a/authfs/src/main.rs b/authfs/src/main.rs
index a083381..421cc02 100644
--- a/authfs/src/main.rs
+++ b/authfs/src/main.rs
@@ -43,7 +43,7 @@
 
 use auth::FakeAuthenticator;
 use file::{
-    InMemoryDir, RemoteDirEditor, RemoteFileEditor, RemoteFileReader, RemoteMerkleTreeReader,
+    Attr, InMemoryDir, RemoteDirEditor, RemoteFileEditor, RemoteFileReader, RemoteMerkleTreeReader,
 };
 use fsstat::RemoteFsStatsReader;
 use fsverity::{VerifiedFileEditor, VerifiedFileReader};
@@ -194,16 +194,20 @@
     service: file::VirtFdService,
     remote_fd: i32,
 ) -> Result<AuthFsEntry> {
-    let remote_file = RemoteFileEditor::new(service, remote_fd);
-    Ok(AuthFsEntry::VerifiedNew { editor: VerifiedFileEditor::new(remote_file) })
+    let remote_file = RemoteFileEditor::new(service.clone(), remote_fd);
+    Ok(AuthFsEntry::VerifiedNew {
+        editor: VerifiedFileEditor::new(remote_file),
+        attr: Attr::new_file(service, remote_fd),
+    })
 }
 
 fn new_remote_new_verified_dir_entry(
     service: file::VirtFdService,
     remote_fd: i32,
 ) -> Result<AuthFsEntry> {
-    let dir = RemoteDirEditor::new(service, remote_fd);
-    Ok(AuthFsEntry::VerifiedNewDirectory { dir })
+    let dir = RemoteDirEditor::new(service.clone(), remote_fd);
+    let attr = Attr::new_dir(service, remote_fd);
+    Ok(AuthFsEntry::VerifiedNewDirectory { dir, attr })
 }
 
 fn prepare_root_dir_entries(