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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 | { |
174 | struct xfs_mount *mp = ip->i_mount; |
175 | char *buf; |
176 | |
177 | xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); |
178 | |
179 | if (!xfs_has_crc(mp)) { |
180 | bp->b_ops = NULL; |
181 | memcpy(bp->b_addr, ifp->if_data, ifp->if_bytes); |
182 | xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1); |
183 | return; |
184 | } |
185 | |
186 | /* |
187 | * As this symlink fits in an inode literal area, it must also fit in |
188 | * the smallest buffer the filesystem supports. |
189 | */ |
190 | ASSERT(BBTOB(bp->b_length) >= |
191 | ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr)); |
192 | |
193 | bp->b_ops = &xfs_symlink_buf_ops; |
194 | |
195 | buf = bp->b_addr; |
196 | buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp); |
197 | memcpy(buf, ifp->if_data, ifp->if_bytes); |
198 | xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) + |
199 | ifp->if_bytes - 1); |
200 | } |
201 | |
202 | /* |
203 | * Verify the in-memory consistency of an inline symlink data fork. This |
204 | * does not do on-disk format checks. |
205 | */ |
206 | xfs_failaddr_t |
207 | xfs_symlink_shortform_verify( |
208 | void *sfp, |
209 | int64_t size) |
210 | { |
211 | char *endp = sfp + size; |
212 | |
213 | /* |
214 | * Zero length symlinks should never occur in memory as they are |
215 | * never allowed to exist on disk. |
216 | */ |
217 | if (!size) |
218 | return __this_address; |
219 | |
220 | /* No negative sizes or overly long symlink targets. */ |
221 | if (size < 0 || size > XFS_SYMLINK_MAXLEN) |
222 | return __this_address; |
223 | |
224 | /* No NULLs in the target either. */ |
225 | if (memchr(sfp, 0, size - 1)) |
226 | return __this_address; |
227 | |
228 | /* We /did/ null-terminate the buffer, right? */ |
229 | if (*endp != 0) |
230 | return __this_address; |
231 | return NULL; |
232 | } |
233 | |
234 | /* Read a remote symlink target into the buffer. */ |
235 | int |
236 | xfs_symlink_remote_read( |
237 | struct xfs_inode *ip, |
238 | char *link) |
239 | { |
240 | struct xfs_mount *mp = ip->i_mount; |
241 | struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; |
242 | struct xfs_buf *bp; |
243 | xfs_daddr_t d; |
244 | char *cur_chunk; |
245 | int pathlen = ip->i_disk_size; |
246 | int nmaps = XFS_SYMLINK_MAPS; |
247 | int byte_cnt; |
248 | int n; |
249 | int error = 0; |
250 | int fsblocks = 0; |
251 | int offset; |
252 | |
253 | xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL); |
254 | |
255 | fsblocks = xfs_symlink_blocks(mp, pathlen); |
256 | error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); |
257 | if (error) |
258 | goto out; |
259 | |
260 | offset = 0; |
261 | for (n = 0; n < nmaps; n++) { |
262 | d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); |
263 | byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); |
264 | |
265 | error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, |
266 | &bp, &xfs_symlink_buf_ops); |
267 | if (xfs_metadata_is_sick(error)) |
268 | xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
269 | if (error) |
270 | return error; |
271 | byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); |
272 | if (pathlen < byte_cnt) |
273 | byte_cnt = pathlen; |
274 | |
275 | cur_chunk = bp->b_addr; |
276 | if (xfs_has_crc(mp)) { |
277 | if (!xfs_symlink_hdr_ok(ip->i_ino, offset, |
278 | byte_cnt, bp)) { |
279 | xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
280 | error = -EFSCORRUPTED; |
281 | xfs_alert(mp, |
282 | "symlink header does not match required off/len/owner (0x%x/0x%x,0x%llx)" , |
283 | offset, byte_cnt, ip->i_ino); |
284 | xfs_buf_relse(bp); |
285 | goto out; |
286 | |
287 | } |
288 | |
289 | cur_chunk += sizeof(struct xfs_dsymlink_hdr); |
290 | } |
291 | |
292 | memcpy(link + offset, cur_chunk, byte_cnt); |
293 | |
294 | pathlen -= byte_cnt; |
295 | offset += byte_cnt; |
296 | |
297 | xfs_buf_relse(bp); |
298 | } |
299 | ASSERT(pathlen == 0); |
300 | |
301 | link[ip->i_disk_size] = '\0'; |
302 | error = 0; |
303 | |
304 | out: |
305 | return error; |
306 | } |
307 | |
308 | /* Write the symlink target into the inode. */ |
309 | int |
310 | xfs_symlink_write_target( |
311 | struct xfs_trans *tp, |
312 | struct xfs_inode *ip, |
313 | const char *target_path, |
314 | int pathlen, |
315 | xfs_fsblock_t fs_blocks, |
316 | uint resblks) |
317 | { |
318 | struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; |
319 | struct xfs_mount *mp = tp->t_mountp; |
320 | const char *cur_chunk; |
321 | struct xfs_buf *bp; |
322 | xfs_daddr_t d; |
323 | int byte_cnt; |
324 | int nmaps; |
325 | int offset = 0; |
326 | int n; |
327 | int error; |
328 | |
329 | /* |
330 | * If the symlink will fit into the inode, write it inline. |
331 | */ |
332 | if (pathlen <= xfs_inode_data_fork_size(ip)) { |
333 | xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); |
334 | |
335 | ip->i_disk_size = pathlen; |
336 | ip->i_df.if_format = XFS_DINODE_FMT_LOCAL; |
337 | xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); |
338 | return 0; |
339 | } |
340 | |
341 | nmaps = XFS_SYMLINK_MAPS; |
342 | error = xfs_bmapi_write(tp, ip, 0, fs_blocks, XFS_BMAPI_METADATA, |
343 | resblks, mval, &nmaps); |
344 | if (error) |
345 | return error; |
346 | |
347 | ip->i_disk_size = pathlen; |
348 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
349 | |
350 | cur_chunk = target_path; |
351 | offset = 0; |
352 | for (n = 0; n < nmaps; n++) { |
353 | char *buf; |
354 | |
355 | d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); |
356 | byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); |
357 | error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, |
358 | BTOBB(byte_cnt), 0, &bp); |
359 | if (error) |
360 | return error; |
361 | bp->b_ops = &xfs_symlink_buf_ops; |
362 | |
363 | byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); |
364 | byte_cnt = min(byte_cnt, pathlen); |
365 | |
366 | buf = bp->b_addr; |
367 | buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, byte_cnt, |
368 | bp); |
369 | |
370 | memcpy(buf, cur_chunk, byte_cnt); |
371 | |
372 | cur_chunk += byte_cnt; |
373 | pathlen -= byte_cnt; |
374 | offset += byte_cnt; |
375 | |
376 | xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); |
377 | xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - |
378 | (char *)bp->b_addr); |
379 | } |
380 | ASSERT(pathlen == 0); |
381 | return 0; |
382 | } |
383 | |