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