From bffc34c94b9bb194423065f77bdaa0ff7778439c Mon Sep 17 00:00:00 2001
From: YanWQ-monad <YanWQmonad@gmail.com>
Date: Wed, 10 Jul 2024 22:17:08 +0800
Subject: [PATCH] Don't check access mode if the file is being created

---
 kernel/aster-nix/src/fs/fs_resolver.rs        | 19 ++++++++++---------
 .../aster-nix/src/fs/inode_handle/dyn_cap.rs  | 10 ++++++++++
 .../blocklists.exfat/open_create_test         |  4 ++++
 test/syscall_test/blocklists/open_create_test |  4 ----
 4 files changed, 24 insertions(+), 13 deletions(-)
 create mode 100644 test/syscall_test/blocklists.exfat/open_create_test

diff --git a/kernel/aster-nix/src/fs/fs_resolver.rs b/kernel/aster-nix/src/fs/fs_resolver.rs
index 3dd8aa9c..ec6f6f38 100644
--- a/kernel/aster-nix/src/fs/fs_resolver.rs
+++ b/kernel/aster-nix/src/fs/fs_resolver.rs
@@ -70,7 +70,7 @@ impl FsResolver {
         let follow_tail_link = !(creation_flags.contains(CreationFlags::O_NOFOLLOW)
             || creation_flags.contains(CreationFlags::O_CREAT)
                 && creation_flags.contains(CreationFlags::O_EXCL));
-        let dentry = match self.lookup_inner(path, follow_tail_link) {
+        let inode_handle = match self.lookup_inner(path, follow_tail_link) {
             Ok(dentry) => {
                 let inode = dentry.inode();
                 if inode.type_() == InodeType::SymLink
@@ -92,7 +92,11 @@ impl FsResolver {
                         "O_DIRECTORY is specified but file is not a directory"
                     );
                 }
-                dentry
+
+                if creation_flags.contains(CreationFlags::O_TRUNC) {
+                    dentry.resize(0)?;
+                }
+                InodeHandle::new(dentry, access_mode, status_flags)?
             }
             Err(e)
                 if e.error() == Errno::ENOENT
@@ -109,17 +113,14 @@ impl FsResolver {
                 if !dir_dentry.mode()?.is_writable() {
                     return_errno_with_message!(Errno::EACCES, "file cannot be created");
                 }
-                dir_dentry.new_fs_child(&file_name, InodeType::File, inode_mode)?
+
+                let dentry = dir_dentry.new_fs_child(&file_name, InodeType::File, inode_mode)?;
+                // Don't check access mode for newly created file
+                InodeHandle::new_unchecked_access(dentry, access_mode, status_flags)?
             }
             Err(e) => return Err(e),
         };
 
-        if creation_flags.contains(CreationFlags::O_TRUNC) {
-            dentry.resize(0)?;
-        }
-
-        let inode_handle = InodeHandle::new(dentry, access_mode, status_flags)?;
-
         Ok(inode_handle)
     }
 
diff --git a/kernel/aster-nix/src/fs/inode_handle/dyn_cap.rs b/kernel/aster-nix/src/fs/inode_handle/dyn_cap.rs
index e2a416dd..2d872da6 100644
--- a/kernel/aster-nix/src/fs/inode_handle/dyn_cap.rs
+++ b/kernel/aster-nix/src/fs/inode_handle/dyn_cap.rs
@@ -19,6 +19,16 @@ impl InodeHandle<Rights> {
         if access_mode.is_writable() && !inode.mode()?.is_writable() {
             return_errno_with_message!(Errno::EACCES, "File is not writable");
         }
+
+        Self::new_unchecked_access(dentry, access_mode, status_flags)
+    }
+
+    pub fn new_unchecked_access(
+        dentry: Arc<Dentry>,
+        access_mode: AccessMode,
+        status_flags: StatusFlags,
+    ) -> Result<Self> {
+        let inode = dentry.inode();
         if access_mode.is_writable() && inode.type_() == InodeType::Dir {
             return_errno_with_message!(Errno::EISDIR, "Directory cannot open to write");
         }
diff --git a/test/syscall_test/blocklists.exfat/open_create_test b/test/syscall_test/blocklists.exfat/open_create_test
new file mode 100644
index 00000000..da3b635d
--- /dev/null
+++ b/test/syscall_test/blocklists.exfat/open_create_test
@@ -0,0 +1,4 @@
+CreateTest.ChmodReadToWriteBetweenOpens_NoRandomSave
+CreateTest.ChmodWriteToReadBetweenOpens_NoRandomSave
+CreateTest.CreateWithReadFlagNotAllowedByMode_NoRandomSave
+CreateTest.CreateWithWriteFlagNotAllowedByMode_NoRandomSave
diff --git a/test/syscall_test/blocklists/open_create_test b/test/syscall_test/blocklists/open_create_test
index d2dc2462..3a3f8b73 100644
--- a/test/syscall_test/blocklists/open_create_test
+++ b/test/syscall_test/blocklists/open_create_test
@@ -3,7 +3,3 @@ CreateTest.CreatWithOTrunc
 CreateTest.CreatDirWithOTruncAndReadOnly
 CreateTest.CreateFailsOnUnpermittedDir
 CreateTest.CreateFailsOnDirWithoutWritePerms
-CreateTest.ChmodReadToWriteBetweenOpens_NoRandomSave
-CreateTest.ChmodWriteToReadBetweenOpens_NoRandomSave
-CreateTest.CreateWithReadFlagNotAllowedByMode_NoRandomSave
-CreateTest.CreateWithWriteFlagNotAllowedByMode_NoRandomSave
\ No newline at end of file