1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  *   Copyright (C) 2021 Samsung Electronics Co., Ltd.
4  */
5 
6 #ifndef __XATTR_H__
7 #define __XATTR_H__
8 
9 /*
10  * These are on-disk structures to store additional metadata into xattr to
11  * reproduce windows filesystem semantics. And they are encoded with NDR to
12  * compatible with samba's xattr meta format. The compatibility with samba
13  * is important because it can lose the information(file attribute,
14  * creation time, acls) about the existing files when switching between
15  * ksmbd and samba.
16  */
17 
18 /*
19  * Dos attribute flags used for what variable is valid.
20  */
21 enum {
22 	XATTR_DOSINFO_ATTRIB		= 0x00000001,
23 	XATTR_DOSINFO_EA_SIZE		= 0x00000002,
24 	XATTR_DOSINFO_SIZE		= 0x00000004,
25 	XATTR_DOSINFO_ALLOC_SIZE	= 0x00000008,
26 	XATTR_DOSINFO_CREATE_TIME	= 0x00000010,
27 	XATTR_DOSINFO_CHANGE_TIME	= 0x00000020,
28 	XATTR_DOSINFO_ITIME		= 0x00000040
29 };
30 
31 /*
32  * Dos attribute structure which is compatible with samba's one.
33  * Storing it into the xattr named "DOSATTRIB" separately from inode
34  * allows ksmbd to faithfully reproduce windows filesystem semantics
35  * on top of a POSIX filesystem.
36  */
37 struct xattr_dos_attrib {
38 	__u16	version;	/* version 3 or version 4 */
39 	__u32	flags;		/* valid flags */
40 	__u32	attr;		/* Dos attribute */
41 	__u32	ea_size;	/* EA size */
42 	__u64	size;
43 	__u64	alloc_size;
44 	__u64	create_time;	/* File creation time */
45 	__u64	change_time;	/* File change time */
46 	__u64	itime;		/* Invented/Initial time */
47 };
48 
49 /*
50  * Enumeration is used for computing posix acl hash.
51  */
52 enum {
53 	SMB_ACL_TAG_INVALID = 0,
54 	SMB_ACL_USER,
55 	SMB_ACL_USER_OBJ,
56 	SMB_ACL_GROUP,
57 	SMB_ACL_GROUP_OBJ,
58 	SMB_ACL_OTHER,
59 	SMB_ACL_MASK
60 };
61 
62 #define SMB_ACL_READ			4
63 #define SMB_ACL_WRITE			2
64 #define SMB_ACL_EXECUTE			1
65 
66 struct xattr_acl_entry {
67 	int type;
68 	uid_t uid;
69 	gid_t gid;
70 	mode_t perm;
71 };
72 
73 /*
74  * xattr_smb_acl structure is used for computing posix acl hash.
75  */
76 struct xattr_smb_acl {
77 	int count;
78 	int next;
79 	struct xattr_acl_entry entries[] __counted_by(count);
80 };
81 
82 /* 64bytes hash in xattr_ntacl is computed with sha256 */
83 #define XATTR_SD_HASH_TYPE_SHA256	0x1
84 #define XATTR_SD_HASH_SIZE		64
85 
86 /*
87  * xattr_ntacl is used for storing ntacl and hashes.
88  * Hash is used for checking valid posix acl and ntacl in xattr.
89  */
90 struct xattr_ntacl {
91 	__u16	version; /* version 4*/
92 	void	*sd_buf;
93 	__u32	sd_size;
94 	__u16	hash_type; /* hash type */
95 	__u8	desc[10]; /* posix_acl description */
96 	__u16	desc_len;
97 	__u64	current_time;
98 	__u8	hash[XATTR_SD_HASH_SIZE]; /* 64bytes hash for ntacl */
99 	__u8	posix_acl_hash[XATTR_SD_HASH_SIZE]; /* 64bytes hash for posix acl */
100 };
101 
102 /* DOS ATTRIBUTE XATTR PREFIX */
103 #define DOS_ATTRIBUTE_PREFIX		"DOSATTRIB"
104 #define DOS_ATTRIBUTE_PREFIX_LEN	(sizeof(DOS_ATTRIBUTE_PREFIX) - 1)
105 #define XATTR_NAME_DOS_ATTRIBUTE	(XATTR_USER_PREFIX DOS_ATTRIBUTE_PREFIX)
106 #define XATTR_NAME_DOS_ATTRIBUTE_LEN	\
107 		(sizeof(XATTR_USER_PREFIX DOS_ATTRIBUTE_PREFIX) - 1)
108 
109 /* STREAM XATTR PREFIX */
110 #define STREAM_PREFIX			"DosStream."
111 #define STREAM_PREFIX_LEN		(sizeof(STREAM_PREFIX) - 1)
112 #define XATTR_NAME_STREAM		(XATTR_USER_PREFIX STREAM_PREFIX)
113 #define XATTR_NAME_STREAM_LEN		(sizeof(XATTR_NAME_STREAM) - 1)
114 
115 /* SECURITY DESCRIPTOR(NTACL) XATTR PREFIX */
116 #define SD_PREFIX			"NTACL"
117 #define SD_PREFIX_LEN	(sizeof(SD_PREFIX) - 1)
118 #define XATTR_NAME_SD	(XATTR_SECURITY_PREFIX SD_PREFIX)
119 #define XATTR_NAME_SD_LEN	\
120 		(sizeof(XATTR_SECURITY_PREFIX SD_PREFIX) - 1)
121 
122 #endif /* __XATTR_H__ */
123