From: Aurelien Aptel <aaptel@suse.com>
Date: Thu, 6 Feb 2020 18:16:55 +0100
Subject: [PATCH] cifs: fix mode bits from dir listing when mounted with
 modefromsid
Git-commit: e3e056c35108661e418c803adfc054bf683426e7
References: bsc#1144333
Patch-mainline: v5.6-rc1

When mounting with -o modefromsid, the mode bits are stored in an
ACE. Directory enumeration (e.g. ls -l /mnt) triggers an SMB Query Dir
which does not include ACEs in its response. The mode bits in this
case are silently set to a default value of 755 instead.

This patch marks the dentry created during the directory enumeration
as needing re-evaluation (i.e. additional Query Info with ACEs) so
that the mode bits can be properly extracted.

Quick repro:

$ mount.cifs //win19.test/data /mnt -o ...,modefromsid
$ touch /mnt/foo && chmod 751 /mnt/foo
$ stat /mnt/foo
  # reports 751 (OK)
$ sleep 2
  # dentry older than 1s by default get invalidated
$ ls -l /mnt
  # since dentry invalid, ls does a Query Dir
  # and reports foo as 755 (WRONG)

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
 fs/cifs/readdir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index d17587c2c4ab..ba9dadf3be24 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -196,7 +196,8 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 	 * may look wrong since the inodes may not have timed out by the time
 	 * "ls" does a stat() call on them.
 	 */
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
+	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
 		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
-- 
2.25.1