1 /* 2 * Copyright (C) 2008 Christoph Hellwig. 3 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 19 #include "xfs.h" 20 #include "xfs_format.h" 21 #include "xfs_log_format.h" 22 #include "xfs_trans_resv.h" 23 #include "xfs_mount.h" 24 #include "xfs_da_format.h" 25 #include "xfs_inode.h" 26 #include "xfs_attr.h" 27 #include "xfs_attr_leaf.h" 28 #include "xfs_acl.h" 29 30 #include <linux/posix_acl_xattr.h> 31 #include <linux/xattr.h> 32 33 34 static int 35 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *dentry, 36 const char *name, void *value, size_t size) 37 { 38 int xflags = handler->flags; 39 struct xfs_inode *ip = XFS_I(d_inode(dentry)); 40 int error, asize = size; 41 42 if (strcmp(name, "") == 0) 43 return -EINVAL; 44 45 /* Convert Linux syscall to XFS internal ATTR flags */ 46 if (!size) { 47 xflags |= ATTR_KERNOVAL; 48 value = NULL; 49 } 50 51 error = xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags); 52 if (error) 53 return error; 54 return asize; 55 } 56 57 void 58 xfs_forget_acl( 59 struct inode *inode, 60 const char *name, 61 int xflags) 62 { 63 /* 64 * Invalidate any cached ACLs if the user has bypassed the ACL 65 * interface. We don't validate the content whatsoever so it is caller 66 * responsibility to provide data in valid format and ensure i_mode is 67 * consistent. 68 */ 69 if (xflags & ATTR_ROOT) { 70 #ifdef CONFIG_XFS_POSIX_ACL 71 if (!strcmp(name, SGI_ACL_FILE)) 72 forget_cached_acl(inode, ACL_TYPE_ACCESS); 73 else if (!strcmp(name, SGI_ACL_DEFAULT)) 74 forget_cached_acl(inode, ACL_TYPE_DEFAULT); 75 #endif 76 } 77 } 78 79 static int 80 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *dentry, 81 const char *name, const void *value, size_t size, int flags) 82 { 83 int xflags = handler->flags; 84 struct xfs_inode *ip = XFS_I(d_inode(dentry)); 85 int error; 86 87 if (strcmp(name, "") == 0) 88 return -EINVAL; 89 90 /* Convert Linux syscall to XFS internal ATTR flags */ 91 if (flags & XATTR_CREATE) 92 xflags |= ATTR_CREATE; 93 if (flags & XATTR_REPLACE) 94 xflags |= ATTR_REPLACE; 95 96 if (!value) 97 return xfs_attr_remove(ip, (unsigned char *)name, xflags); 98 error = xfs_attr_set(ip, (unsigned char *)name, 99 (void *)value, size, xflags); 100 if (!error) 101 xfs_forget_acl(d_inode(dentry), name, xflags); 102 103 return error; 104 } 105 106 static const struct xattr_handler xfs_xattr_user_handler = { 107 .prefix = XATTR_USER_PREFIX, 108 .flags = 0, /* no flags implies user namespace */ 109 .get = xfs_xattr_get, 110 .set = xfs_xattr_set, 111 }; 112 113 static const struct xattr_handler xfs_xattr_trusted_handler = { 114 .prefix = XATTR_TRUSTED_PREFIX, 115 .flags = ATTR_ROOT, 116 .get = xfs_xattr_get, 117 .set = xfs_xattr_set, 118 }; 119 120 static const struct xattr_handler xfs_xattr_security_handler = { 121 .prefix = XATTR_SECURITY_PREFIX, 122 .flags = ATTR_SECURE, 123 .get = xfs_xattr_get, 124 .set = xfs_xattr_set, 125 }; 126 127 const struct xattr_handler *xfs_xattr_handlers[] = { 128 &xfs_xattr_user_handler, 129 &xfs_xattr_trusted_handler, 130 &xfs_xattr_security_handler, 131 #ifdef CONFIG_XFS_POSIX_ACL 132 &posix_acl_access_xattr_handler, 133 &posix_acl_default_xattr_handler, 134 #endif 135 NULL 136 }; 137 138 static unsigned int xfs_xattr_prefix_len(int flags) 139 { 140 if (flags & XFS_ATTR_SECURE) 141 return sizeof("security"); 142 else if (flags & XFS_ATTR_ROOT) 143 return sizeof("trusted"); 144 else 145 return sizeof("user"); 146 } 147 148 static const char *xfs_xattr_prefix(int flags) 149 { 150 if (flags & XFS_ATTR_SECURE) 151 return xfs_xattr_security_handler.prefix; 152 else if (flags & XFS_ATTR_ROOT) 153 return xfs_xattr_trusted_handler.prefix; 154 else 155 return xfs_xattr_user_handler.prefix; 156 } 157 158 static int 159 xfs_xattr_put_listent( 160 struct xfs_attr_list_context *context, 161 int flags, 162 unsigned char *name, 163 int namelen, 164 int valuelen, 165 unsigned char *value) 166 { 167 unsigned int prefix_len = xfs_xattr_prefix_len(flags); 168 char *offset; 169 int arraytop; 170 171 ASSERT(context->count >= 0); 172 173 /* 174 * Only show root namespace entries if we are actually allowed to 175 * see them. 176 */ 177 if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN)) 178 return 0; 179 180 arraytop = context->count + prefix_len + namelen + 1; 181 if (arraytop > context->firstu) { 182 context->count = -1; /* insufficient space */ 183 return 1; 184 } 185 offset = (char *)context->alist + context->count; 186 strncpy(offset, xfs_xattr_prefix(flags), prefix_len); 187 offset += prefix_len; 188 strncpy(offset, (char *)name, namelen); /* real name */ 189 offset += namelen; 190 *offset = '\0'; 191 context->count += prefix_len + namelen + 1; 192 return 0; 193 } 194 195 static int 196 xfs_xattr_put_listent_sizes( 197 struct xfs_attr_list_context *context, 198 int flags, 199 unsigned char *name, 200 int namelen, 201 int valuelen, 202 unsigned char *value) 203 { 204 context->count += xfs_xattr_prefix_len(flags) + namelen + 1; 205 return 0; 206 } 207 208 static int 209 list_one_attr(const char *name, const size_t len, void *data, 210 size_t size, ssize_t *result) 211 { 212 char *p = data + *result; 213 214 *result += len; 215 if (!size) 216 return 0; 217 if (*result > size) 218 return -ERANGE; 219 220 strcpy(p, name); 221 return 0; 222 } 223 224 ssize_t 225 xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size) 226 { 227 struct xfs_attr_list_context context; 228 struct attrlist_cursor_kern cursor = { 0 }; 229 struct inode *inode = d_inode(dentry); 230 int error; 231 232 /* 233 * First read the regular on-disk attributes. 234 */ 235 memset(&context, 0, sizeof(context)); 236 context.dp = XFS_I(inode); 237 context.cursor = &cursor; 238 context.resynch = 1; 239 context.alist = data; 240 context.bufsize = size; 241 context.firstu = context.bufsize; 242 243 if (size) 244 context.put_listent = xfs_xattr_put_listent; 245 else 246 context.put_listent = xfs_xattr_put_listent_sizes; 247 248 xfs_attr_list_int(&context); 249 if (context.count < 0) 250 return -ERANGE; 251 252 /* 253 * Then add the two synthetic ACL attributes. 254 */ 255 if (posix_acl_access_exists(inode)) { 256 error = list_one_attr(POSIX_ACL_XATTR_ACCESS, 257 strlen(POSIX_ACL_XATTR_ACCESS) + 1, 258 data, size, &context.count); 259 if (error) 260 return error; 261 } 262 263 if (posix_acl_default_exists(inode)) { 264 error = list_one_attr(POSIX_ACL_XATTR_DEFAULT, 265 strlen(POSIX_ACL_XATTR_DEFAULT) + 1, 266 data, size, &context.count); 267 if (error) 268 return error; 269 } 270 271 return context.count; 272 } 273