From 385a86fa4704ec11f19564ea42eaf677b283e6ce Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Sat, 21 Sep 2024 23:28:32 -0500
Subject: [PATCH] smb3: fix incorrect mode displayed for read-only files
Commands like "chmod 0444" mark a file readonly via the attribute flag
(when mapping of mode bits into the ACL are not set, or POSIX extensions
are not negotiated), but they were not reported correctly for stat of
directories (they were reported ok for files and for "ls"). See example
below:
root:~# ls /mnt2 -l
total 12
drwxr-xr-x 2 root root 0 Sep 21 18:03 normaldir
-rwxr-xr-x 1 root root 0 Sep 21 23:24 normalfile
dr-xr-xr-x 2 root root 0 Sep 21 17:55 readonly-dir
-r-xr-xr-x 1 root root 209716224 Sep 21 18:15 readonly-file
root:~# stat -c %a /mnt2/readonly-dir
755
root:~# stat -c %a /mnt2/readonly-file
555
This fixes the stat of directories when ATTR_READONLY is set
(in cases where the mode can not be obtained other ways).
root:~# stat -c %a /mnt2/readonly-dir
555
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/smb/client/inode.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
@@ -800,10 +800,6 @@ static void cifs_open_info_to_fattr(struct cifs_fattr *fattr,
fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
fattr->cf_dtype = DT_REG;
- /* clear write bits if ATTR_READONLY is set */
- if (fattr->cf_cifsattrs & ATTR_READONLY)
- fattr->cf_mode &= ~(S_IWUGO);
-
/*
* Don't accept zero nlink from non-unix servers unless
* delete is pending. Instead mark it as unknown.
@@ -816,6 +812,10 @@ static void cifs_open_info_to_fattr(struct cifs_fattr *fattr,
}
}
+ /* clear write bits if ATTR_READONLY is set */
+ if (fattr->cf_cifsattrs & ATTR_READONLY)
+ fattr->cf_mode &= ~(S_IWUGO);
+
out_reparse:
if (S_ISLNK(fattr->cf_mode)) {
if (likely(data->symlink_target))
@@ -1233,11 +1233,14 @@ static int cifs_get_fattr(struct cifs_open_info_data *data,
__func__, rc);
goto out;
}
- }
-
- /* fill in remaining high mode bits e.g. SUID, VTX */
- if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
+ } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
+ /* fill in remaining high mode bits e.g. SUID, VTX */
cifs_sfu_mode(fattr, full_path, cifs_sb, xid);
+ else if (!(tcon->posix_extensions))
+ /* clear write bits if ATTR_READONLY is set */
+ if (fattr->cf_cifsattrs & ATTR_READONLY)
+ fattr->cf_mode &= ~(S_IWUGO);
+
/* check for Minshall+French symlinks */
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
--
2.43.0
In investigating a problem that Maxim pointed out (with rmdir when file has read only attribute set - which will be fixed with a different patch), we noticed a bug with "stat" of directories when readonly. See attached fix. Commands like "chmod 0444" mark a file readonly via the attribute flag (when mapping of mode bits into the ACL are not set, or POSIX extensions are not negotiated), but they were not reported correctly for stat of directories (they were reported ok for files and for "ls"). See example below: root:~# ls /mnt2 -l total 12 drwxr-xr-x 2 root root 0 Sep 21 18:03 normaldir -rwxr-xr-x 1 root root 0 Sep 21 23:24 normalfile dr-xr-xr-x 2 root root 0 Sep 21 17:55 readonly-dir -r-xr-xr-x 1 root root 209716224 Sep 21 18:15 readonly-file root:~# stat -c %a /mnt2/readonly-dir 755 root:~# stat -c %a /mnt2/readonly-file 555 This fixes the stat of directories when ATTR_READONLY is set (in cases where the mode can not be obtained other ways). See below stat output with patch applied: root:~# stat -c %a /mnt2/readonly-dir 555