CIFS: Add support for setting owner info, dos attributes, and create time

This is needed for backup/restore scenarios among others.

Add extended attribute "system.cifs_ntsd" (and alias "system.smb3_ntsd")
to allow for setting owner and DACL in the security descriptor. This is in
addition to the existing "system.cifs_acl" and "system.smb3_acl" attributes
that allow for setting DACL only. Add support for setting creation time and
dos attributes using set_file_info() calls to complement the existing
support for getting these attributes via query_path_info() calls.

Signed-off-by: Boris Protopopov <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: bprotopopov

fs/cifs/xattr.c

@@ -32,20 +32,71 @@
 #include "cifs_unicode.h"
 
 #define MAX_EA_VALUE_SIZE CIFSMaxBufSize
-#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
+#define CIFS_XATTR_CIFS_ACL "system.cifs_acl" /* DACL only */
+#define CIFS_XATTR_CIFS_NTSD "system.cifs_ntsd" /* owner plus DACL */
 #define CIFS_XATTR_ATTRIB "cifs.dosattrib"  /* full name: user.cifs.dosattrib */
 #define CIFS_XATTR_CREATETIME "cifs.creationtime"  /* user.cifs.creationtime */
 /*
  * Although these three are just aliases for the above, need to move away from
  * confusing users and using the 20+ year old term 'cifs' when it is no longer
  * secure, replaced by SMB2 (then even more highly secure SMB3) many years ago
  */
-#define SMB3_XATTR_CIFS_ACL "system.smb3_acl"
+#define SMB3_XATTR_CIFS_ACL "system.smb3_acl" /* DACL only */
+#define SMB3_XATTR_CIFS_NTSD "system.smb3_ntsd" /* owner plus DACL */
 #define SMB3_XATTR_ATTRIB "smb3.dosattrib"  /* full name: user.smb3.dosattrib */
 #define SMB3_XATTR_CREATETIME "smb3.creationtime"  /* user.smb3.creationtime */
 /* BB need to add server (Samba e.g) support for security and trusted prefix */
 
-enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
+enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT,
+	XATTR_CIFS_NTSD };
+
+static int cifs_attrib_set(unsigned int xid, struct cifs_tcon *pTcon,
+			   struct inode *inode, char *full_path,
+			   const void *value, size_t size)
+{
+	ssize_t rc = -EOPNOTSUPP;
+	__u32 *pattrib = (__u32 *)value;
+	__u32 attrib;
+	FILE_BASIC_INFO info_buf;
+
+	if ((value == NULL) || (size != sizeof(__u32)))
+		return -ERANGE;
+
+	memset(&info_buf, 0, sizeof(info_buf));
+	attrib = *pattrib;
+	info_buf.Attributes = cpu_to_le32(attrib);
+	if (pTcon->ses->server->ops->set_file_info)
+		rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
+				&info_buf, xid);
+	if (rc == 0)
+		CIFS_I(inode)->cifsAttrs = attrib;
+
+	return rc;
+}
+
+static int cifs_creation_time_set(unsigned int xid, struct cifs_tcon *pTcon,
+				  struct inode *inode, char *full_path,
+				  const void *value, size_t size)
+{
+	ssize_t rc = -EOPNOTSUPP;
+	__u64 *pcreation_time = (__u64 *)value;
+	__u64 creation_time;
+	FILE_BASIC_INFO info_buf;
+
+	if ((value == NULL) || (size != sizeof(__u64)))
+		return -ERANGE;
+
+	memset(&info_buf, 0, sizeof(info_buf));
+	creation_time = *pcreation_time;
+	info_buf.CreationTime = cpu_to_le64(creation_time);
+	if (pTcon->ses->server->ops->set_file_info)
+		rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
+				&info_buf, xid);
+	if (rc == 0)
+		CIFS_I(inode)->createtime = creation_time;
+
+	return rc;
+}
 
 static int cifs_xattr_set(const struct xattr_handler *handler,
 			  struct dentry *dentry, struct inode *inode,
@@ -86,6 +137,23 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
 
 	switch (handler->flags) {
 	case XATTR_USER:
+		cifs_dbg(FYI, "%s:setting user xattr %s\n", __func__, name);
+		if ((strcmp(name, CIFS_XATTR_ATTRIB) == 0) ||
+		    (strcmp(name, SMB3_XATTR_ATTRIB) == 0)) {
+			rc = cifs_attrib_set(xid, pTcon, inode, full_path,
+					value, size);
+			if (rc == 0) /* force revalidate of the inode */
+				CIFS_I(inode)->time = 0;
+			break;
+		} else if ((strcmp(name, CIFS_XATTR_CREATETIME) == 0) ||
+			   (strcmp(name, SMB3_XATTR_CREATETIME) == 0)) {
+			rc = cifs_creation_time_set(xid, pTcon, inode,
+					full_path, value, size);
+			if (rc == 0) /* force revalidate of the inode */
+				CIFS_I(inode)->time = 0;
+			break;
+		}
+
 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 			goto out;
 
@@ -95,7 +163,8 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
 				cifs_sb->local_nls, cifs_sb);
 		break;
 
-	case XATTR_CIFS_ACL: {
+	case XATTR_CIFS_ACL:
+	case XATTR_CIFS_NTSD: {
 		struct cifs_ntsd *pacl;
 
 		if (!value)
@@ -106,12 +175,25 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
 		} else {
 			memcpy(pacl, value, size);
 			if (value &&
-			    pTcon->ses->server->ops->set_acl)
-				rc = pTcon->ses->server->ops->set_acl(pacl,
-						size, inode,
-						full_path, CIFS_ACL_DACL);
-			else
+			    pTcon->ses->server->ops->set_acl) {
+				rc = 0;
+				if (handler->flags == XATTR_CIFS_NTSD) {
+					/* set owner and DACL */
+					rc = pTcon->ses->server->ops->set_acl(
+							pacl, size, inode,
+							full_path,
+							CIFS_ACL_OWNER);
+				}
+				if (rc == 0) {
+					/* set DACL */
+					rc = pTcon->ses->server->ops->set_acl(
+							pacl, size, inode,
+							full_path,
+							CIFS_ACL_DACL);
+				}
+			} else {
 				rc = -EOPNOTSUPP;
+			}
 			if (rc == 0) /* force revalidate of the inode */
 				CIFS_I(inode)->time = 0;
 			kfree(pacl);
@@ -179,7 +261,7 @@ static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
 				  void *value, size_t size)
 {
 	ssize_t rc;
-	__u64 * pcreatetime;
+	__u64 *pcreatetime;
 
 	rc = cifs_revalidate_dentry_attr(dentry);
 	if (rc)
@@ -244,7 +326,9 @@ static int cifs_xattr_get(const struct xattr_handler *handler,
 				full_path, name, value, size, cifs_sb);
 		break;
 
-	case XATTR_CIFS_ACL: {
+	case XATTR_CIFS_ACL:
+	case XATTR_CIFS_NTSD: {
+		/* the whole ntsd is fetched regardless */
 		u32 acllen;
 		struct cifs_ntsd *pacl;
 
@@ -382,6 +466,26 @@ static const struct xattr_handler smb3_acl_xattr_handler = {
 	.set = cifs_xattr_set,
 };
 
+static const struct xattr_handler cifs_cifs_ntsd_xattr_handler = {
+	.name = CIFS_XATTR_CIFS_NTSD,
+	.flags = XATTR_CIFS_NTSD,
+	.get = cifs_xattr_get,
+	.set = cifs_xattr_set,
+};
+
+/*
+ * Although this is just an alias for the above, need to move away from
+ * confusing users and using the 20 year old term 'cifs' when it is no
+ * longer secure and was replaced by SMB2/SMB3 a long time ago, and
+ * SMB3 and later are highly secure.
+ */
+static const struct xattr_handler smb3_ntsd_xattr_handler = {
+	.name = SMB3_XATTR_CIFS_NTSD,
+	.flags = XATTR_CIFS_NTSD,
+	.get = cifs_xattr_get,
+	.set = cifs_xattr_set,
+};
+
 static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
 	.name = XATTR_NAME_POSIX_ACL_ACCESS,
 	.flags = XATTR_ACL_ACCESS,
@@ -401,6 +505,8 @@ const struct xattr_handler *cifs_xattr_handlers[] = {
 	&cifs_os2_xattr_handler,
 	&cifs_cifs_acl_xattr_handler,
 	&smb3_acl_xattr_handler, /* alias for above since avoiding "cifs" */
+	&cifs_cifs_ntsd_xattr_handler,
+	&smb3_ntsd_xattr_handler, /* alias for above since avoiding "cifs" */
 	&cifs_posix_acl_access_xattr_handler,
 	&cifs_posix_acl_default_xattr_handler,
 	NULL