reparse.h

  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(&ctime, &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 */