git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 6f8a394aa952257575910d57cf0a63627fa949a2 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
   3 Date: Sat, 5 Apr 2025 19:51:07 +0200
   4 Subject: cifs: Ensure that all non-client-specific reparse points are processed by the server
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 From: Pali Rohár <pali@kernel.org>
  10
  11 commit 6f8a394aa952257575910d57cf0a63627fa949a2 upstream.
  12
  13 Fix regression in mounts to e.g. onedrive shares.
  14
  15 Generally, reparse points are processed by the SMB server during the
  16 SMB OPEN request, but there are few reparse points which do not have
  17 OPEN-like meaning for the SMB server and has to be processed by the SMB
  18 client. Those are symlinks and special files (fifo, socket, block, char).
  19
  20 For Linux SMB client, it is required to process also name surrogate reparse
  21 points as they represent another entity on the SMB server system. Linux
  22 client will mark them as separate mount points. Examples of name surrogate
  23 reparse points are NTFS junction points (e.g. created by the "mklink" tool
  24 on Windows servers).
  25
  26 So after processing the name surrogate reparse points, clear the
  27 -EOPNOTSUPP error code returned from the parse_reparse_point() to let SMB
  28 server to process reparse points.
  29
  30 And remove printing misleading error message "unhandled reparse tag:" as
  31 reparse points are handled by SMB server and hence unhandled fact is normal
  32 operation.
  33
  34 Fixes: cad3fc0a4c8c ("cifs: Throw -EOPNOTSUPP error on unsupported reparse point type from parse_reparse_point()")
  35 Fixes: b587fd128660 ("cifs: Treat unhandled directory name surrogate reparse points as mount directory nodes")
  36 Cc: stable@vger.kernel.org
  37 Reported-by: Junwen Sun <sunjw8888@gmail.com>
  38 Tested-by: Junwen Sun <sunjw8888@gmail.com>
  39 Signed-off-by: Pali Rohár <pali@kernel.org>
  40 Signed-off-by: Steve French <stfrench@microsoft.com>
  41 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  42 ---
  43  fs/smb/client/inode.c   |   10 ++++++++++
  44  fs/smb/client/reparse.c |    4 ----
  45  2 files changed, 10 insertions(+), 4 deletions(-)
  46
  47 --- a/fs/smb/client/inode.c
  48 +++ b/fs/smb/client/inode.c
  49 @@ -1206,6 +1206,16 @@ static int reparse_info_to_fattr(struct
  50                                 cifs_create_junction_fattr(fattr, sb);
  51                                 goto out;
  52                         }
  53 +                       /*
  54 +                        * If the reparse point is unsupported by the Linux SMB
  55 +                        * client then let it process by the SMB server. So mask
  56 +                        * the -EOPNOTSUPP error code. This will allow Linux SMB
  57 +                        * client to send SMB OPEN request to server. If server
  58 +                        * does not support this reparse point too then server
  59 +                        * will return error during open the path.
  60 +                        */
  61 +                       if (rc == -EOPNOTSUPP)
  62 +                               rc = 0;
  63                 }
  64                 break;
  65         }
  66 --- a/fs/smb/client/reparse.c
  67 +++ b/fs/smb/client/reparse.c
  68 @@ -633,8 +633,6 @@ int parse_reparse_point(struct reparse_d
  69                         const char *full_path,
  70                         bool unicode, struct cifs_open_info_data *data)
  71  {
  72 -       struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
  73 -
  74         data->reparse.buf = buf;
  75
  76         /* See MS-FSCC 2.1.2 */
  77 @@ -658,8 +656,6 @@ int parse_reparse_point(struct reparse_d
  78                 }
  79                 return 0;
  80         default:
  81 -               cifs_tcon_dbg(VFS | ONCE, "unhandled reparse tag: 0x%08x\n",
  82 -                             le32_to_cpu(buf->ReparseTag));
  83                 return -EOPNOTSUPP;
  84         }
  85  }