1 /*
2 * include/linux/nfsd/nfsfh.h
3 *
4 * This file describes the layout of the file handles as passed
5 * over the wire.
6 *
7 * Earlier versions of knfsd used to sign file handles using keyed MD5
8 * or SHA. I've removed this code, because it doesn't give you more
9 * security than blocking external access to port 2049 on your firewall.
10 *
11 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
12 */
13
14 #ifndef _LINUX_NFSD_FH_H
15 #define _LINUX_NFSD_FH_H
16
17 #include <asm/types.h>
18 #ifdef __KERNEL__
19 # include <linux/config.h>
20 # include <linux/types.h>
21 # include <linux/string.h>
22 # include <linux/fs.h>
23 #endif
24 #include <linux/nfsd/const.h>
25 #include <linux/nfsd/debug.h>
26
27 /*
28 * This is the old "dentry style" Linux NFSv2 file handle.
29 *
30 * The xino and xdev fields are currently used to transport the
31 * ino/dev of the exported inode.
32 */
33 struct nfs_fhbase_old {
34 __u32 fb_dcookie; /* dentry cookie - always 0xfeebbaca */
35 __u32 fb_ino; /* our inode number */
36 __u32 fb_dirino; /* dir inode number, 0 for directories */
37 __u32 fb_dev; /* our device */
38 __u32 fb_xdev;
39 __u32 fb_xino;
40 __u32 fb_generation;
41 };
42
43 /*
44 * This is the new flexible, extensible style NFSv2/v3 file handle.
45 * by Neil Brown <neilb@cse.unsw.edu.au> - March 2000
46 *
47 * The file handle is seens as a list of 4byte words.
48 * The first word contains a version number (1) and four descriptor bytes
49 * that tell how the remaining 3 variable length fields should be handled.
50 * These three bytes are auth_type, fsid_type and fileid_type.
51 *
52 * All 4byte values are in host-byte-order.
53 *
54 * The auth_type field specifies how the filehandle can be authenticated
55 * This might allow a file to be confirmed to be in a writable part of a
56 * filetree without checking the path from it upto the root.
57 * Current values:
58 * 0 - No authentication. fb_auth is 0 bytes long
59 * Possible future values:
60 * 1 - 4 bytes taken from MD5 hash of the remainer of the file handle
61 * prefixed by a secret and with the important export flags.
62 *
63 * The fsid_type identifies how the filesystem (or export point) is
64 * encoded.
65 * Current values:
66 * 0 - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
67 * NOTE: we cannot use the kdev_t device id value, because kdev_t.h
68 * says we mustn't. We must break it up and reassemble.
69 * Possible future encodings:
70 * 1 - 4 byte user specified identifier
71 *
72 * The fileid_type identified how the file within the filesystem is encoded.
73 * This is (will be) passed to, and set by, the underlying filesystem if it supports
74 * filehandle operations. The filesystem must not use the value '0' or '0xff' and may
75 * only use the values 1 and 2 as defined below:
76 * Current values:
77 * 0 - The root, or export point, of the filesystem. fb_fileid is 0 bytes.
78 * 1 - 32bit inode number, 32 bit generation number.
79 * 2 - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
80 *
81 */
82 struct nfs_fhbase_new {
83 __u8 fb_version; /* == 1, even => nfs_fhbase_old */
84 __u8 fb_auth_type;
85 __u8 fb_fsid_type;
86 __u8 fb_fileid_type;
87 __u32 fb_auth[1];
88 /* __u32 fb_fsid[0]; floating */
89 /* __u32 fb_fileid[0]; floating */
90 };
91
92 struct knfsd_fh {
93 unsigned int fh_size; /* significant for NFSv3.
94 * Points to the current size while building
95 * a new file handle
96 */
97 union {
98 struct nfs_fhbase_old fh_old;
99 __u32 fh_pad[NFS3_FHSIZE/4];
100 struct nfs_fhbase_new fh_new;
101 } fh_base;
102 };
103
104 #define ofh_dcookie fh_base.fh_old.fb_dcookie
105 #define ofh_ino fh_base.fh_old.fb_ino
106 #define ofh_dirino fh_base.fh_old.fb_dirino
107 #define ofh_dev fh_base.fh_old.fb_dev
108 #define ofh_xdev fh_base.fh_old.fb_xdev
109 #define ofh_xino fh_base.fh_old.fb_xino
110 #define ofh_generation fh_base.fh_old.fb_generation
111
112 #define fh_version fh_base.fh_new.fb_version
113 #define fh_fsid_type fh_base.fh_new.fb_fsid_type
114 #define fh_auth_type fh_base.fh_new.fb_auth_type
115 #define fh_fileid_type fh_base.fh_new.fb_fileid_type
116 #define fh_auth fh_base.fh_new.fb_auth
117
118 #ifdef __KERNEL__
119
120 /*
121 * Conversion macros for the filehandle fields.
122 */
kdev_t_to_u32(kdev_t dev)123 static inline __u32 kdev_t_to_u32(kdev_t dev)
124 {
125 return (__u32) dev;
126 }
127
u32_to_kdev_t(__u32 udev)128 static inline kdev_t u32_to_kdev_t(__u32 udev)
129 {
130 return (kdev_t) udev;
131 }
132
ino_t_to_u32(ino_t ino)133 static inline __u32 ino_t_to_u32(ino_t ino)
134 {
135 return (__u32) ino;
136 }
137
u32_to_ino_t(__u32 uino)138 static inline ino_t u32_to_ino_t(__u32 uino)
139 {
140 return (ino_t) uino;
141 }
142
143 /*
144 * This is the internal representation of an NFS handle used in knfsd.
145 * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
146 */
147 typedef struct svc_fh {
148 struct knfsd_fh fh_handle; /* FH data */
149 struct dentry * fh_dentry; /* validated dentry */
150 struct svc_export * fh_export; /* export pointer */
151 int fh_maxsize; /* max size for fh_handle */
152
153 unsigned char fh_locked; /* inode locked by us */
154
155 #ifdef CONFIG_NFSD_V3
156 unsigned char fh_post_saved; /* post-op attrs saved */
157 unsigned char fh_pre_saved; /* pre-op attrs saved */
158
159 /* Pre-op attributes saved during fh_lock */
160 __u64 fh_pre_size; /* size before operation */
161 time_t fh_pre_mtime; /* mtime before oper */
162 time_t fh_pre_ctime; /* ctime before oper */
163
164 /* Post-op attributes saved in fh_unlock */
165 umode_t fh_post_mode; /* i_mode */
166 nlink_t fh_post_nlink; /* i_nlink */
167 uid_t fh_post_uid; /* i_uid */
168 gid_t fh_post_gid; /* i_gid */
169 __u64 fh_post_size; /* i_size */
170 unsigned long fh_post_blocks; /* i_blocks */
171 unsigned long fh_post_blksize;/* i_blksize */
172 kdev_t fh_post_rdev; /* i_rdev */
173 time_t fh_post_atime; /* i_atime */
174 time_t fh_post_mtime; /* i_mtime */
175 time_t fh_post_ctime; /* i_ctime */
176 #endif /* CONFIG_NFSD_V3 */
177
178 } svc_fh;
179
180 /*
181 * Shorthand for dprintk()'s
182 */
SVCFH_fmt(struct svc_fh * fhp)183 inline static char * SVCFH_fmt(struct svc_fh *fhp)
184 {
185 struct knfsd_fh *fh = &fhp->fh_handle;
186
187 static char buf[80];
188 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
189 fh->fh_size,
190 fh->fh_base.fh_pad[0],
191 fh->fh_base.fh_pad[1],
192 fh->fh_base.fh_pad[2],
193 fh->fh_base.fh_pad[3],
194 fh->fh_base.fh_pad[4],
195 fh->fh_base.fh_pad[5]);
196 return buf;
197 }
198 /*
199 * Function prototypes
200 */
201 u32 fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
202 int fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
203 int fh_update(struct svc_fh *);
204 void fh_put(struct svc_fh *);
205
206 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,struct svc_fh * src)207 fh_copy(struct svc_fh *dst, struct svc_fh *src)
208 {
209 if (src->fh_dentry || src->fh_locked) {
210 struct dentry *dentry = src->fh_dentry;
211 printk(KERN_ERR "fh_copy: copying %s/%s, already verified!\n",
212 dentry->d_parent->d_name.name, dentry->d_name.name);
213 }
214
215 *dst = *src;
216 return dst;
217 }
218
219 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)220 fh_init(struct svc_fh *fhp, int maxsize)
221 {
222 memset(fhp, 0, sizeof(*fhp));
223 fhp->fh_maxsize = maxsize;
224 return fhp;
225 }
226
227 #ifdef CONFIG_NFSD_V3
228 /*
229 * Fill in the pre_op attr for the wcc data
230 */
231 static inline void
fill_pre_wcc(struct svc_fh * fhp)232 fill_pre_wcc(struct svc_fh *fhp)
233 {
234 struct inode *inode;
235
236 inode = fhp->fh_dentry->d_inode;
237 if (!fhp->fh_pre_saved) {
238 fhp->fh_pre_mtime = inode->i_mtime;
239 fhp->fh_pre_ctime = inode->i_ctime;
240 fhp->fh_pre_size = inode->i_size;
241 fhp->fh_pre_saved = 1;
242 }
243 }
244
245 /*
246 * Fill in the post_op attr for the wcc data
247 */
248 static inline void
fill_post_wcc(struct svc_fh * fhp)249 fill_post_wcc(struct svc_fh *fhp)
250 {
251 struct inode *inode = fhp->fh_dentry->d_inode;
252
253 if (fhp->fh_post_saved)
254 printk("nfsd: inode locked twice during operation.\n");
255
256 fhp->fh_post_mode = inode->i_mode;
257 fhp->fh_post_nlink = inode->i_nlink;
258 fhp->fh_post_uid = inode->i_uid;
259 fhp->fh_post_gid = inode->i_gid;
260 fhp->fh_post_size = inode->i_size;
261 if (inode->i_blksize) {
262 fhp->fh_post_blksize = inode->i_blksize;
263 fhp->fh_post_blocks = inode->i_blocks;
264 } else {
265 fhp->fh_post_blksize = BLOCK_SIZE;
266 /* how much do we care for accuracy with MinixFS? */
267 fhp->fh_post_blocks = (inode->i_size+511) >> 9;
268 }
269 fhp->fh_post_rdev = inode->i_rdev;
270 fhp->fh_post_atime = inode->i_atime;
271 fhp->fh_post_mtime = inode->i_mtime;
272 fhp->fh_post_ctime = inode->i_ctime;
273 fhp->fh_post_saved = 1;
274 }
275 #else
276 #define fill_pre_wcc(ignored)
277 #define fill_post_wcc(notused)
278 #endif /* CONFIG_NFSD_V3 */
279
280
281 /*
282 * Lock a file handle/inode
283 * NOTE: both fh_lock and fh_unlock are done "by hand" in
284 * vfs.c:nfsd_rename as it needs to grab 2 i_sem's at once
285 * so, any changes here should be reflected there.
286 */
287 static inline void
fh_lock(struct svc_fh * fhp)288 fh_lock(struct svc_fh *fhp)
289 {
290 struct dentry *dentry = fhp->fh_dentry;
291 struct inode *inode;
292
293 dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
294 SVCFH_fmt(fhp), fhp->fh_locked);
295
296 if (!fhp->fh_dentry) {
297 printk(KERN_ERR "fh_lock: fh not verified!\n");
298 return;
299 }
300 if (fhp->fh_locked) {
301 printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
302 dentry->d_parent->d_name.name, dentry->d_name.name);
303 return;
304 }
305
306 inode = dentry->d_inode;
307 down(&inode->i_sem);
308 fill_pre_wcc(fhp);
309 fhp->fh_locked = 1;
310 }
311
312 /*
313 * Unlock a file handle/inode
314 */
315 static inline void
fh_unlock(struct svc_fh * fhp)316 fh_unlock(struct svc_fh *fhp)
317 {
318 if (!fhp->fh_dentry)
319 printk(KERN_ERR "fh_unlock: fh not verified!\n");
320
321 if (fhp->fh_locked) {
322 fill_post_wcc(fhp);
323 up(&fhp->fh_dentry->d_inode->i_sem);
324 fhp->fh_locked = 0;
325 }
326 }
327 #endif /* __KERNEL__ */
328
329
330 #endif /* _LINUX_NFSD_FH_H */
331