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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Pavel Shilovsky" <pshilov@microsoft.com>,
        "Steve French" <stfrench@microsoft.com>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.534988148@decadent.org.uk>
Subject: [PATCH 3.16 182/328] SMB3: Backup intent flag missing for
 directory opens with backupuid mounts
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Steve French <stfrench@microsoft.com>

commit 5e19697b56a64004e2d0ff1bb952ea05493c088f upstream.

When "backup intent" is requested on the mount (e.g. backupuid or
backupgid mount options), the corresponding flag needs to be set
on opens of directories (and files) but was missing in some
places causing access denied trying to enumerate and backup
servers.

Fixes kernel bugzilla #200953
https://bugzilla.kernel.org/show_bug.cgi?id=200953

Reported-and-tested-by: <whh@rubrik.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
[bwh: Backported to 3.16: drop changes in smb2_query_eas(), smb2_set_ea()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -446,6 +446,8 @@ cifs_sfu_type(struct cifs_fattr *fattr,
 	oparms.cifs_sb = cifs_sb;
 	oparms.desired_access = GENERIC_READ;
 	oparms.create_options = CREATE_NOT_DIR;
+	if (backup_cred(cifs_sb))
+		oparms.create_options |= CREATE_OPEN_BACKUP_INTENT;
 	oparms.disposition = FILE_OPEN;
 	oparms.path = path;
 	oparms.fid = &fid;
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -315,7 +315,10 @@ smb2_is_path_accessible(const unsigned i
 	oparms.tcon = tcon;
 	oparms.desired_access = FILE_READ_ATTRIBUTES;
 	oparms.disposition = FILE_OPEN;
-	oparms.create_options = 0;
+	if (backup_cred(cifs_sb))
+		oparms.create_options = CREATE_OPEN_BACKUP_INTENT;
+	else
+		oparms.create_options = 0;
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
@@ -725,7 +728,10 @@ smb2_query_dir_first(const unsigned int
 	oparms.tcon = tcon;
 	oparms.desired_access = FILE_READ_ATTRIBUTES | FILE_READ_DATA;
 	oparms.disposition = FILE_OPEN;
-	oparms.create_options = 0;
+	if (backup_cred(cifs_sb))
+		oparms.create_options = CREATE_OPEN_BACKUP_INTENT;
+	else
+		oparms.create_options = 0;
 	oparms.fid = fid;
 	oparms.reconnect = false;
 
@@ -891,7 +897,10 @@ smb2_query_symlink(const unsigned int xi
 	oparms.tcon = tcon;
 	oparms.desired_access = FILE_READ_ATTRIBUTES;
 	oparms.disposition = FILE_OPEN;
-	oparms.create_options = 0;
+	if (backup_cred(cifs_sb))
+		oparms.create_options = CREATE_OPEN_BACKUP_INTENT;
+	else
+		oparms.create_options = 0;
 	oparms.fid = &fid;
 	oparms.reconnect = false;