1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * Copyright (c) 2012-2013 Red Hat, Inc.
5 * All rights reserved.
6 */
7 #include "xfs.h"
8 #include "xfs_fs.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_shared.h"
12 #include "xfs_trans_resv.h"
13 #include "xfs_mount.h"
14 #include "xfs_inode.h"
15 #include "xfs_error.h"
16 #include "xfs_trans.h"
17 #include "xfs_buf_item.h"
18 #include "xfs_log.h"
19 #include "xfs_symlink_remote.h"
20 #include "xfs_bit.h"
21 #include "xfs_bmap.h"
22 #include "xfs_health.h"
23
24 /*
25 * Each contiguous block has a header, so it is not just a simple pathlen
26 * to FSB conversion.
27 */
28 int
xfs_symlink_blocks(struct xfs_mount * mp,int pathlen)29 xfs_symlink_blocks(
30 struct xfs_mount *mp,
31 int pathlen)
32 {
33 int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
34
35 return (pathlen + buflen - 1) / buflen;
36 }
37
38 int
xfs_symlink_hdr_set(struct xfs_mount * mp,xfs_ino_t ino,uint32_t offset,uint32_t size,struct xfs_buf * bp)39 xfs_symlink_hdr_set(
40 struct xfs_mount *mp,
41 xfs_ino_t ino,
42 uint32_t offset,
43 uint32_t size,
44 struct xfs_buf *bp)
45 {
46 struct xfs_dsymlink_hdr *dsl = bp->b_addr;
47
48 if (!xfs_has_crc(mp))
49 return 0;
50
51 memset(dsl, 0, sizeof(struct xfs_dsymlink_hdr));
52 dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC);
53 dsl->sl_offset = cpu_to_be32(offset);
54 dsl->sl_bytes = cpu_to_be32(size);
55 uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid);
56 dsl->sl_owner = cpu_to_be64(ino);
57 dsl->sl_blkno = cpu_to_be64(xfs_buf_daddr(bp));
58 bp->b_ops = &xfs_symlink_buf_ops;
59
60 return sizeof(struct xfs_dsymlink_hdr);
61 }
62
63 /*
64 * Checking of the symlink header is split into two parts. the verifier does
65 * CRC, location and bounds checking, the unpacking function checks the path
66 * parameters and owner.
67 */
68 bool
xfs_symlink_hdr_ok(xfs_ino_t ino,uint32_t offset,uint32_t size,struct xfs_buf * bp)69 xfs_symlink_hdr_ok(
70 xfs_ino_t ino,
71 uint32_t offset,
72 uint32_t size,
73 struct xfs_buf *bp)
74 {
75 struct xfs_dsymlink_hdr *dsl = bp->b_addr;
76
77 if (offset != be32_to_cpu(dsl->sl_offset))
78 return false;
79 if (size != be32_to_cpu(dsl->sl_bytes))
80 return false;
81 if (ino != be64_to_cpu(dsl->sl_owner))
82 return false;
83
84 /* ok */
85 return true;
86 }
87
88 static xfs_failaddr_t
xfs_symlink_verify(struct xfs_buf * bp)89 xfs_symlink_verify(
90 struct xfs_buf *bp)
91 {
92 struct xfs_mount *mp = bp->b_mount;
93 struct xfs_dsymlink_hdr *dsl = bp->b_addr;
94
95 if (!xfs_has_crc(mp))
96 return __this_address;
97 if (!xfs_verify_magic(bp, dsl->sl_magic))
98 return __this_address;
99 if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid))
100 return __this_address;
101 if (xfs_buf_daddr(bp) != be64_to_cpu(dsl->sl_blkno))
102 return __this_address;
103 if (be32_to_cpu(dsl->sl_offset) +
104 be32_to_cpu(dsl->sl_bytes) >= XFS_SYMLINK_MAXLEN)
105 return __this_address;
106 if (dsl->sl_owner == 0)
107 return __this_address;
108 if (!xfs_log_check_lsn(mp, be64_to_cpu(dsl->sl_lsn)))
109 return __this_address;
110
111 return NULL;
112 }
113
114 static void
xfs_symlink_read_verify(struct xfs_buf * bp)115 xfs_symlink_read_verify(
116 struct xfs_buf *bp)
117 {
118 struct xfs_mount *mp = bp->b_mount;
119 xfs_failaddr_t fa;
120
121 /* no verification of non-crc buffers */
122 if (!xfs_has_crc(mp))
123 return;
124
125 if (!xfs_buf_verify_cksum(bp, XFS_SYMLINK_CRC_OFF))
126 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
127 else {
128 fa = xfs_symlink_verify(bp);
129 if (fa)
130 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
131 }
132 }
133
134 static void
xfs_symlink_write_verify(struct xfs_buf * bp)135 xfs_symlink_write_verify(
136 struct xfs_buf *bp)
137 {
138 struct xfs_mount *mp = bp->b_mount;
139 struct xfs_buf_log_item *bip = bp->b_log_item;
140 xfs_failaddr_t fa;
141
142 /* no verification of non-crc buffers */
143 if (!xfs_has_crc(mp))
144 return;
145
146 fa = xfs_symlink_verify(bp);
147 if (fa) {
148 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
149 return;
150 }
151
152 if (bip) {
153 struct xfs_dsymlink_hdr *dsl = bp->b_addr;
154 dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
155 }
156 xfs_buf_update_cksum(bp, XFS_SYMLINK_CRC_OFF);
157 }
158
159 const struct xfs_buf_ops xfs_symlink_buf_ops = {
160 .name = "xfs_symlink",
161 .magic = { 0, cpu_to_be32(XFS_SYMLINK_MAGIC) },
162 .verify_read = xfs_symlink_read_verify,
163 .verify_write = xfs_symlink_write_verify,
164 .verify_struct = xfs_symlink_verify,
165 };
166
167 void
xfs_symlink_local_to_remote(struct xfs_trans * tp,struct xfs_buf * bp,struct xfs_inode * ip,struct xfs_ifork * ifp,void * priv)168 xfs_symlink_local_to_remote(
169 struct xfs_trans *tp,
170 struct xfs_buf *bp,
171 struct xfs_inode *ip,
172 struct xfs_ifork *ifp,
173 void *priv)
174 {
175 struct xfs_mount *mp = ip->i_mount;
176 char *buf;
177
178 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
179
180 if (!xfs_has_crc(mp)) {
181 bp->b_ops = NULL;
182 memcpy(bp->b_addr, ifp->if_data, ifp->if_bytes);
183 xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1);
184 return;
185 }
186
187 /*
188 * As this symlink fits in an inode literal area, it must also fit in
189 * the smallest buffer the filesystem supports.
190 */
191 ASSERT(BBTOB(bp->b_length) >=
192 ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));
193
194 bp->b_ops = &xfs_symlink_buf_ops;
195
196 buf = bp->b_addr;
197 buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
198 memcpy(buf, ifp->if_data, ifp->if_bytes);
199 xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) +
200 ifp->if_bytes - 1);
201 }
202
203 /*
204 * Verify the in-memory consistency of an inline symlink data fork. This
205 * does not do on-disk format checks.
206 */
207 xfs_failaddr_t
xfs_symlink_shortform_verify(void * sfp,int64_t size)208 xfs_symlink_shortform_verify(
209 void *sfp,
210 int64_t size)
211 {
212 char *endp = sfp + size;
213
214 /*
215 * Zero length symlinks should never occur in memory as they are
216 * never allowed to exist on disk.
217 */
218 if (!size)
219 return __this_address;
220
221 /* No negative sizes or overly long symlink targets. */
222 if (size < 0 || size > XFS_SYMLINK_MAXLEN)
223 return __this_address;
224
225 /* No NULLs in the target either. */
226 if (memchr(sfp, 0, size - 1))
227 return __this_address;
228
229 /* We /did/ null-terminate the buffer, right? */
230 if (*endp != 0)
231 return __this_address;
232 return NULL;
233 }
234
235 /* Read a remote symlink target into the buffer. */
236 int
xfs_symlink_remote_read(struct xfs_inode * ip,char * link)237 xfs_symlink_remote_read(
238 struct xfs_inode *ip,
239 char *link)
240 {
241 struct xfs_mount *mp = ip->i_mount;
242 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
243 struct xfs_buf *bp;
244 xfs_daddr_t d;
245 char *cur_chunk;
246 int pathlen = ip->i_disk_size;
247 int nmaps = XFS_SYMLINK_MAPS;
248 int byte_cnt;
249 int n;
250 int error = 0;
251 int fsblocks = 0;
252 int offset;
253
254 xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
255
256 fsblocks = xfs_symlink_blocks(mp, pathlen);
257 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
258 if (error)
259 goto out;
260
261 offset = 0;
262 for (n = 0; n < nmaps; n++) {
263 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
264 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
265
266 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
267 &bp, &xfs_symlink_buf_ops);
268 if (xfs_metadata_is_sick(error))
269 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
270 if (error)
271 return error;
272 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
273 if (pathlen < byte_cnt)
274 byte_cnt = pathlen;
275
276 cur_chunk = bp->b_addr;
277 if (xfs_has_crc(mp)) {
278 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
279 byte_cnt, bp)) {
280 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
281 error = -EFSCORRUPTED;
282 xfs_alert(mp,
283 "symlink header does not match required off/len/owner (0x%x/0x%x,0x%llx)",
284 offset, byte_cnt, ip->i_ino);
285 xfs_buf_relse(bp);
286 goto out;
287
288 }
289
290 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
291 }
292
293 memcpy(link + offset, cur_chunk, byte_cnt);
294
295 pathlen -= byte_cnt;
296 offset += byte_cnt;
297
298 xfs_buf_relse(bp);
299 }
300 ASSERT(pathlen == 0);
301
302 link[ip->i_disk_size] = '\0';
303 error = 0;
304
305 out:
306 return error;
307 }
308
309 /* Write the symlink target into the inode. */
310 int
xfs_symlink_write_target(struct xfs_trans * tp,struct xfs_inode * ip,xfs_ino_t owner,const char * target_path,int pathlen,xfs_fsblock_t fs_blocks,uint resblks)311 xfs_symlink_write_target(
312 struct xfs_trans *tp,
313 struct xfs_inode *ip,
314 xfs_ino_t owner,
315 const char *target_path,
316 int pathlen,
317 xfs_fsblock_t fs_blocks,
318 uint resblks)
319 {
320 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
321 struct xfs_mount *mp = tp->t_mountp;
322 const char *cur_chunk;
323 struct xfs_buf *bp;
324 xfs_daddr_t d;
325 int byte_cnt;
326 int nmaps;
327 int offset = 0;
328 int n;
329 int error;
330
331 /*
332 * If the symlink will fit into the inode, write it inline.
333 */
334 if (pathlen <= xfs_inode_data_fork_size(ip)) {
335 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
336
337 ip->i_disk_size = pathlen;
338 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
339 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
340 return 0;
341 }
342
343 nmaps = XFS_SYMLINK_MAPS;
344 error = xfs_bmapi_write(tp, ip, 0, fs_blocks, XFS_BMAPI_METADATA,
345 resblks, mval, &nmaps);
346 if (error)
347 return error;
348
349 ip->i_disk_size = pathlen;
350 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
351
352 cur_chunk = target_path;
353 offset = 0;
354 for (n = 0; n < nmaps; n++) {
355 char *buf;
356
357 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
358 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
359 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
360 BTOBB(byte_cnt), 0, &bp);
361 if (error)
362 return error;
363 bp->b_ops = &xfs_symlink_buf_ops;
364
365 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
366 byte_cnt = min(byte_cnt, pathlen);
367
368 buf = bp->b_addr;
369 buf += xfs_symlink_hdr_set(mp, owner, offset, byte_cnt, bp);
370
371 memcpy(buf, cur_chunk, byte_cnt);
372
373 cur_chunk += byte_cnt;
374 pathlen -= byte_cnt;
375 offset += byte_cnt;
376
377 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
378 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
379 (char *)bp->b_addr);
380 }
381 ASSERT(pathlen == 0);
382 return 0;
383 }
384
385 /* Remove all the blocks from a symlink and invalidate buffers. */
386 int
xfs_symlink_remote_truncate(struct xfs_trans * tp,struct xfs_inode * ip)387 xfs_symlink_remote_truncate(
388 struct xfs_trans *tp,
389 struct xfs_inode *ip)
390 {
391 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
392 struct xfs_mount *mp = tp->t_mountp;
393 struct xfs_buf *bp;
394 int nmaps = XFS_SYMLINK_MAPS;
395 int done = 0;
396 int i;
397 int error;
398
399 /* Read mappings and invalidate buffers. */
400 error = xfs_bmapi_read(ip, 0, XFS_MAX_FILEOFF, mval, &nmaps, 0);
401 if (error)
402 return error;
403
404 for (i = 0; i < nmaps; i++) {
405 if (!xfs_bmap_is_real_extent(&mval[i]))
406 break;
407
408 error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
409 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
410 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
411 &bp);
412 if (error)
413 return error;
414
415 xfs_trans_binval(tp, bp);
416 }
417
418 /* Unmap the remote blocks. */
419 error = xfs_bunmapi(tp, ip, 0, XFS_MAX_FILEOFF, 0, nmaps, &done);
420 if (error)
421 return error;
422 if (!done) {
423 ASSERT(done);
424 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
425 return -EFSCORRUPTED;
426 }
427
428 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
429 return 0;
430 }
431