1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (c) 2024 Paulo Alcantara <pc@manguebit.com>
4 */
5
6#ifndef _CIFS_REPARSE_H
7#define _CIFS_REPARSE_H
8
9#include <linux/fs.h>
10#include <linux/stat.h>
11#include <linux/uidgid.h>
12#include "fs_context.h"
13#include "cifsglob.h"
14
15#define REPARSE_SYM_PATH_MAX 4060
16
17/*
18 * Used only by cifs.ko to ignore reparse points from files when client or
19 * server doesn't support FSCTL_GET_REPARSE_POINT.
20 */
21#define IO_REPARSE_TAG_INTERNAL ((__u32)~0U)
22
23static inline dev_t reparse_mkdev(void *ptr)
24{
25 u64 v = le64_to_cpu(*(__le64 *)ptr);
26
27 return MKDEV(v & 0xffffffff, v >> 32);
28}
29
30static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
31 void *ptr)
32{
33 u32 uid = le32_to_cpu(*(__le32 *)ptr);
34
35 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
36 return cifs_sb->ctx->linux_uid;
37 return make_kuid(current_user_ns(), uid);
38}
39
40static inline kgid_t wsl_make_kgid(struct cifs_sb_info *cifs_sb,
41 void *ptr)
42{
43 u32 gid = le32_to_cpu(*(__le32 *)ptr);
44
45 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
46 return cifs_sb->ctx->linux_gid;
47 return make_kgid(current_user_ns(), gid);
48}
49
50static inline u64 reparse_mode_nfs_type(mode_t mode)
51{
52 switch (mode & S_IFMT) {
53 case S_IFLNK: return NFS_SPECFILE_LNK;
54 case S_IFBLK: return NFS_SPECFILE_BLK;
55 case S_IFCHR: return NFS_SPECFILE_CHR;
56 case S_IFIFO: return NFS_SPECFILE_FIFO;
57 case S_IFSOCK: return NFS_SPECFILE_SOCK;
58 }
59 return 0;
60}
61
62static inline u32 reparse_mode_wsl_tag(mode_t mode)
63{
64 switch (mode & S_IFMT) {
65 case S_IFLNK: return IO_REPARSE_TAG_LX_SYMLINK;
66 case S_IFBLK: return IO_REPARSE_TAG_LX_BLK;
67 case S_IFCHR: return IO_REPARSE_TAG_LX_CHR;
68 case S_IFIFO: return IO_REPARSE_TAG_LX_FIFO;
69 case S_IFSOCK: return IO_REPARSE_TAG_AF_UNIX;
70 }
71 return 0;
72}
73
74/*
75 * Match a reparse point inode if reparse tag and ctime haven't changed.
76 *
77 * Windows Server updates ctime of reparse points when their data have changed.
78 * The server doesn't allow changing reparse tags from existing reparse points,
79 * though it's worth checking.
80 */
81static inline bool reparse_inode_match(struct inode *inode,
82 struct cifs_fattr *fattr)
83{
84 struct cifsInodeInfo *cinode = CIFS_I(inode);
85 struct timespec64 ctime = inode_get_ctime(inode);
86
87 /*
88 * Do not match reparse tags when client or server doesn't support
89 * FSCTL_GET_REPARSE_POINT. @fattr->cf_cifstag should contain correct
90 * reparse tag from query dir response but the client won't be able to
91 * read the reparse point data anyway. This spares us a revalidation.
92 */
93 if (cinode->reparse_tag != IO_REPARSE_TAG_INTERNAL &&
94 cinode->reparse_tag != fattr->cf_cifstag)
95 return false;
96 return (cinode->cifsAttrs & ATTR_REPARSE_POINT) &&
97 timespec64_equal(a: &ctime, b: &fattr->cf_ctime);
98}
99
100static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
101{
102 u32 attrs;
103 bool ret;
104
105 if (data->contains_posix_file_info) {
106 struct smb311_posix_qinfo *fi = &data->posix_fi;
107
108 attrs = le32_to_cpu(fi->DosAttributes);
109 if (data->reparse_point) {
110 attrs |= ATTR_REPARSE_POINT;
111 fi->DosAttributes = cpu_to_le32(attrs);
112 }
113
114 } else {
115 struct smb2_file_all_info *fi = &data->fi;
116
117 attrs = le32_to_cpu(fi->Attributes);
118 if (data->reparse_point) {
119 attrs |= ATTR_REPARSE_POINT;
120 fi->Attributes = cpu_to_le32(attrs);
121 }
122 }
123
124 ret = attrs & ATTR_REPARSE_POINT;
125
126 return ret;
127}
128
129bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
130 struct cifs_fattr *fattr,
131 struct cifs_open_info_data *data);
132int create_reparse_symlink(const unsigned int xid, struct inode *inode,
133 struct dentry *dentry, struct cifs_tcon *tcon,
134 const char *full_path, const char *symname);
135int mknod_reparse(unsigned int xid, struct inode *inode,
136 struct dentry *dentry, struct cifs_tcon *tcon,
137 const char *full_path, umode_t mode, dev_t dev);
138struct reparse_data_buffer *smb2_get_reparse_point_buffer(const struct kvec *rsp_iov, u32 *len);
139
140#endif /* _CIFS_REPARSE_H */
141

source code of linux/fs/smb/client/reparse.h