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 
23 static 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 
30 static 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 
40 static 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 
50 static 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 
62 static 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  */
81 static 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) &&
97 		timespec64_equal(&ctime, &fattr->cf_ctime);
98 }
99 
100 static 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;
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;
120 			fi->Attributes = cpu_to_le32(attrs);
121 		}
122 	}
123 
124 	ret = attrs & ATTR_REPARSE;
125 
126 	return ret;
127 }
128 
129 bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
130 				 struct cifs_fattr *fattr,
131 				 struct cifs_open_info_data *data);
132 int smb2_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);
135 int smb2_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);
138 struct reparse_data_buffer *smb2_get_reparse_point_buffer(const struct kvec *rsp_iov, u32 *len);
139 
140 #endif /* _CIFS_REPARSE_H */
141