smb3: fix mode passed in on create for modetosid mount option

When using the special SID to store the mode bits in an ACE (See
http://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx)
which is enabled with mount parm "modefromsid" we were not
passing in the mode via SMB3 create (although chmod was enabled).
SMB3 create allows a security descriptor context to be passed
in (which is more atomic and thus preferable to setting the mode
bits after create via a setinfo).

This patch enables setting the mode bits on create when using
modefromsid mount option.  In addition it fixes an endian
error in the definition of the Control field flags in the SMB3
security descriptor. It also makes the ACE type of the special
SID better match the documentation (and behavior of servers
which use this to store mode bits in SMB3 ACLs).

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

1 files changed, 26 insertions, 16 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 06ffe52bdcfa..96ae72b556ac 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -802,6 +802,31 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
 	return;
 }
 
+/*
+ * Fill in the special SID based on the mode. See
+ * http://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx
+ */
+unsigned int setup_special_mode_ACE(struct cifs_ace *pntace, __u64 nmode)
+{
+	int i;
+	unsigned int ace_size = 28;
+
+	pntace->type = ACCESS_DENIED_ACE_TYPE;
+	pntace->flags = 0x0;
+	pntace->access_req = 0;
+	pntace->sid.num_subauth = 3;
+	pntace->sid.revision = 1;
+	for (i = 0; i < NUM_AUTHS; i++)
+		pntace->sid.authority[i] = sid_unix_NFS_mode.authority[i];
+
+	pntace->sid.sub_auth[0] = sid_unix_NFS_mode.sub_auth[0];
+	pntace->sid.sub_auth[1] = sid_unix_NFS_mode.sub_auth[1];
+	pntace->sid.sub_auth[2] = cpu_to_le32(nmode & 07777);
+
+	/* size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth*4) */
+	pntace->size = cpu_to_le16(ace_size);
+	return ace_size;
+}
 
 static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid,
 			struct cifs_sid *pgrpsid, __u64 nmode, bool modefromsid)
@@ -815,23 +840,8 @@ static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid,
 	if (modefromsid) {
 		struct cifs_ace *pntace =
 			(struct cifs_ace *)((char *)pnndacl + size);
-		int i;
 
-		pntace->type = ACCESS_ALLOWED;
-		pntace->flags = 0x0;
-		pntace->access_req = 0;
-		pntace->sid.num_subauth = 3;
-		pntace->sid.revision = 1;
-		for (i = 0; i < NUM_AUTHS; i++)
-			pntace->sid.authority[i] =
-				sid_unix_NFS_mode.authority[i];
-		pntace->sid.sub_auth[0] = sid_unix_NFS_mode.sub_auth[0];
-		pntace->sid.sub_auth[1] = sid_unix_NFS_mode.sub_auth[1];
-		pntace->sid.sub_auth[2] = cpu_to_le32(nmode & 07777);
-
-		/* size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth*4) */
-		pntace->size = cpu_to_le16(28);
-		size += 28;
+		size += setup_special_mode_ACE(pntace, nmode);
 		num_aces++;
 	}