1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2008 Christoph Hellwig. 4 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc. 5 */ 6 7 #include "xfs.h" 8 #include "xfs_shared.h" 9 #include "xfs_format.h" 10 #include "xfs_log_format.h" 11 #include "xfs_da_format.h" 12 #include "xfs_trans_resv.h" 13 #include "xfs_mount.h" 14 #include "xfs_inode.h" 15 #include "xfs_da_btree.h" 16 #include "xfs_attr.h" 17 #include "xfs_acl.h" 18 #include "xfs_log.h" 19 #include "xfs_xattr.h" 20 21 #include <linux/posix_acl_xattr.h> 22 23 /* 24 * Get permission to use log-assisted atomic exchange of file extents. 25 * 26 * Callers must not be running any transactions or hold any inode locks, and 27 * they must release the permission by calling xlog_drop_incompat_feat 28 * when they're done. 29 */ 30 static inline int 31 xfs_attr_grab_log_assist( 32 struct xfs_mount *mp) 33 { 34 int error = 0; 35 36 /* 37 * Protect ourselves from an idle log clearing the logged xattrs log 38 * incompat feature bit. 39 */ 40 xlog_use_incompat_feat(mp->m_log); 41 42 /* 43 * If log-assisted xattrs are already enabled, the caller can use the 44 * log assisted swap functions with the log-incompat reference we got. 45 */ 46 if (xfs_sb_version_haslogxattrs(&mp->m_sb)) 47 return 0; 48 49 /* Enable log-assisted xattrs. */ 50 error = xfs_add_incompat_log_feature(mp, 51 XFS_SB_FEAT_INCOMPAT_LOG_XATTRS); 52 if (error) 53 goto drop_incompat; 54 55 xfs_warn_mount(mp, XFS_OPSTATE_WARNED_LARP, 56 "EXPERIMENTAL logged extended attributes feature in use. Use at your own risk!"); 57 58 return 0; 59 drop_incompat: 60 xlog_drop_incompat_feat(mp->m_log); 61 return error; 62 } 63 64 static inline void 65 xfs_attr_rele_log_assist( 66 struct xfs_mount *mp) 67 { 68 xlog_drop_incompat_feat(mp->m_log); 69 } 70 71 static inline bool 72 xfs_attr_want_log_assist( 73 struct xfs_mount *mp) 74 { 75 #ifdef DEBUG 76 /* Logged xattrs require a V5 super for log_incompat */ 77 return xfs_has_crc(mp) && xfs_globals.larp; 78 #else 79 return false; 80 #endif 81 } 82 83 /* 84 * Set or remove an xattr, having grabbed the appropriate logging resources 85 * prior to calling libxfs. 86 */ 87 int 88 xfs_attr_change( 89 struct xfs_da_args *args) 90 { 91 struct xfs_mount *mp = args->dp->i_mount; 92 bool use_logging = false; 93 int error; 94 95 ASSERT(!(args->op_flags & XFS_DA_OP_LOGGED)); 96 97 if (xfs_attr_want_log_assist(mp)) { 98 error = xfs_attr_grab_log_assist(mp); 99 if (error) 100 return error; 101 102 args->op_flags |= XFS_DA_OP_LOGGED; 103 use_logging = true; 104 } 105 106 error = xfs_attr_set(args); 107 108 if (use_logging) 109 xfs_attr_rele_log_assist(mp); 110 return error; 111 } 112 113 114 static int 115 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused, 116 struct inode *inode, const char *name, void *value, size_t size) 117 { 118 struct xfs_da_args args = { 119 .dp = XFS_I(inode), 120 .attr_filter = handler->flags, 121 .name = name, 122 .namelen = strlen(name), 123 .value = value, 124 .valuelen = size, 125 }; 126 int error; 127 128 error = xfs_attr_get(&args); 129 if (error) 130 return error; 131 return args.valuelen; 132 } 133 134 static int 135 xfs_xattr_set(const struct xattr_handler *handler, 136 struct mnt_idmap *idmap, struct dentry *unused, 137 struct inode *inode, const char *name, const void *value, 138 size_t size, int flags) 139 { 140 struct xfs_da_args args = { 141 .dp = XFS_I(inode), 142 .attr_filter = handler->flags, 143 .attr_flags = flags, 144 .name = name, 145 .namelen = strlen(name), 146 .value = (void *)value, 147 .valuelen = size, 148 }; 149 int error; 150 151 error = xfs_attr_change(&args); 152 if (!error && (handler->flags & XFS_ATTR_ROOT)) 153 xfs_forget_acl(inode, name); 154 return error; 155 } 156 157 static const struct xattr_handler xfs_xattr_user_handler = { 158 .prefix = XATTR_USER_PREFIX, 159 .flags = 0, /* no flags implies user namespace */ 160 .get = xfs_xattr_get, 161 .set = xfs_xattr_set, 162 }; 163 164 static const struct xattr_handler xfs_xattr_trusted_handler = { 165 .prefix = XATTR_TRUSTED_PREFIX, 166 .flags = XFS_ATTR_ROOT, 167 .get = xfs_xattr_get, 168 .set = xfs_xattr_set, 169 }; 170 171 static const struct xattr_handler xfs_xattr_security_handler = { 172 .prefix = XATTR_SECURITY_PREFIX, 173 .flags = XFS_ATTR_SECURE, 174 .get = xfs_xattr_get, 175 .set = xfs_xattr_set, 176 }; 177 178 const struct xattr_handler *xfs_xattr_handlers[] = { 179 &xfs_xattr_user_handler, 180 &xfs_xattr_trusted_handler, 181 &xfs_xattr_security_handler, 182 NULL 183 }; 184 185 static void 186 __xfs_xattr_put_listent( 187 struct xfs_attr_list_context *context, 188 char *prefix, 189 int prefix_len, 190 unsigned char *name, 191 int namelen) 192 { 193 char *offset; 194 int arraytop; 195 196 if (context->count < 0 || context->seen_enough) 197 return; 198 199 if (!context->buffer) 200 goto compute_size; 201 202 arraytop = context->count + prefix_len + namelen + 1; 203 if (arraytop > context->firstu) { 204 context->count = -1; /* insufficient space */ 205 context->seen_enough = 1; 206 return; 207 } 208 offset = context->buffer + context->count; 209 memcpy(offset, prefix, prefix_len); 210 offset += prefix_len; 211 strncpy(offset, (char *)name, namelen); /* real name */ 212 offset += namelen; 213 *offset = '\0'; 214 215 compute_size: 216 context->count += prefix_len + namelen + 1; 217 return; 218 } 219 220 static void 221 xfs_xattr_put_listent( 222 struct xfs_attr_list_context *context, 223 int flags, 224 unsigned char *name, 225 int namelen, 226 int valuelen) 227 { 228 char *prefix; 229 int prefix_len; 230 231 ASSERT(context->count >= 0); 232 233 if (flags & XFS_ATTR_ROOT) { 234 #ifdef CONFIG_XFS_POSIX_ACL 235 if (namelen == SGI_ACL_FILE_SIZE && 236 strncmp(name, SGI_ACL_FILE, 237 SGI_ACL_FILE_SIZE) == 0) { 238 __xfs_xattr_put_listent( 239 context, XATTR_SYSTEM_PREFIX, 240 XATTR_SYSTEM_PREFIX_LEN, 241 XATTR_POSIX_ACL_ACCESS, 242 strlen(XATTR_POSIX_ACL_ACCESS)); 243 } else if (namelen == SGI_ACL_DEFAULT_SIZE && 244 strncmp(name, SGI_ACL_DEFAULT, 245 SGI_ACL_DEFAULT_SIZE) == 0) { 246 __xfs_xattr_put_listent( 247 context, XATTR_SYSTEM_PREFIX, 248 XATTR_SYSTEM_PREFIX_LEN, 249 XATTR_POSIX_ACL_DEFAULT, 250 strlen(XATTR_POSIX_ACL_DEFAULT)); 251 } 252 #endif 253 254 /* 255 * Only show root namespace entries if we are actually allowed to 256 * see them. 257 */ 258 if (!capable(CAP_SYS_ADMIN)) 259 return; 260 261 prefix = XATTR_TRUSTED_PREFIX; 262 prefix_len = XATTR_TRUSTED_PREFIX_LEN; 263 } else if (flags & XFS_ATTR_SECURE) { 264 prefix = XATTR_SECURITY_PREFIX; 265 prefix_len = XATTR_SECURITY_PREFIX_LEN; 266 } else { 267 prefix = XATTR_USER_PREFIX; 268 prefix_len = XATTR_USER_PREFIX_LEN; 269 } 270 271 __xfs_xattr_put_listent(context, prefix, prefix_len, name, 272 namelen); 273 return; 274 } 275 276 ssize_t 277 xfs_vn_listxattr( 278 struct dentry *dentry, 279 char *data, 280 size_t size) 281 { 282 struct xfs_attr_list_context context; 283 struct inode *inode = d_inode(dentry); 284 int error; 285 286 /* 287 * First read the regular on-disk attributes. 288 */ 289 memset(&context, 0, sizeof(context)); 290 context.dp = XFS_I(inode); 291 context.resynch = 1; 292 context.buffer = size ? data : NULL; 293 context.bufsize = size; 294 context.firstu = context.bufsize; 295 context.put_listent = xfs_xattr_put_listent; 296 297 error = xfs_attr_list(&context); 298 if (error) 299 return error; 300 if (context.count < 0) 301 return -ERANGE; 302 303 return context.count; 304 } 305