Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | File: fs/xattr.c |
| 3 | |
| 4 | Extended attribute handling. |
| 5 | |
| 6 | Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> |
| 7 | Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> |
| 8 | Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| 9 | */ |
| 10 | #include <linux/fs.h> |
| 11 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/file.h> |
| 13 | #include <linux/xattr.h> |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 14 | #include <linux/mount.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/namei.h> |
| 16 | #include <linux/security.h> |
| 17 | #include <linux/syscalls.h> |
| 18 | #include <linux/module.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 19 | #include <linux/fsnotify.h> |
Amy Griffis | 73241cc | 2005-11-03 16:00:25 +0000 | [diff] [blame] | 20 | #include <linux/audit.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <asm/uaccess.h> |
| 22 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 23 | |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 24 | /* |
| 25 | * Check permissions for extended attribute access. This is a bit complicated |
| 26 | * because different namespaces have very different rules. |
| 27 | */ |
| 28 | static int |
| 29 | xattr_permission(struct inode *inode, const char *name, int mask) |
| 30 | { |
| 31 | /* |
| 32 | * We can never set or remove an extended attribute on a read-only |
| 33 | * filesystem or on an immutable / append-only inode. |
| 34 | */ |
| 35 | if (mask & MAY_WRITE) { |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 36 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
| 37 | return -EPERM; |
| 38 | } |
| 39 | |
| 40 | /* |
| 41 | * No restriction for security.* and system.* from the VFS. Decision |
| 42 | * on these is left to the underlying filesystem / security module. |
| 43 | */ |
| 44 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || |
| 45 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| 46 | return 0; |
| 47 | |
| 48 | /* |
Andreas Gruenbacher | f1f2d87 | 2006-11-02 22:07:29 -0800 | [diff] [blame] | 49 | * The trusted.* namespace can only be accessed by a privileged user. |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 50 | */ |
| 51 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) |
| 52 | return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM); |
| 53 | |
Andreas Gruenbacher | f1f2d87 | 2006-11-02 22:07:29 -0800 | [diff] [blame] | 54 | /* In user.* namespace, only regular files and directories can have |
| 55 | * extended attributes. For sticky directories, only the owner and |
| 56 | * privileged user can write attributes. |
| 57 | */ |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 58 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
Andreas Gruenbacher | f1f2d87 | 2006-11-02 22:07:29 -0800 | [diff] [blame] | 59 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
| 60 | return -EPERM; |
| 61 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
Satyam Sharma | 3bd858a | 2007-07-17 15:00:08 +0530 | [diff] [blame] | 62 | (mask & MAY_WRITE) && !is_owner_or_cap(inode)) |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 63 | return -EPERM; |
| 64 | } |
| 65 | |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 66 | return inode_permission(inode, mask); |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 67 | } |
| 68 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 69 | int |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 70 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 71 | size_t size, int flags) |
| 72 | { |
| 73 | struct inode *inode = dentry->d_inode; |
| 74 | int error; |
| 75 | |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 76 | error = xattr_permission(inode, name, MAY_WRITE); |
| 77 | if (error) |
| 78 | return error; |
| 79 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 80 | mutex_lock(&inode->i_mutex); |
| 81 | error = security_inode_setxattr(dentry, name, value, size, flags); |
| 82 | if (error) |
| 83 | goto out; |
| 84 | error = -EOPNOTSUPP; |
| 85 | if (inode->i_op->setxattr) { |
| 86 | error = inode->i_op->setxattr(dentry, name, value, size, flags); |
| 87 | if (!error) { |
| 88 | fsnotify_xattr(dentry); |
| 89 | security_inode_post_setxattr(dentry, name, value, |
| 90 | size, flags); |
| 91 | } |
| 92 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 93 | XATTR_SECURITY_PREFIX_LEN)) { |
| 94 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 95 | error = security_inode_setsecurity(inode, suffix, value, |
| 96 | size, flags); |
| 97 | if (!error) |
| 98 | fsnotify_xattr(dentry); |
| 99 | } |
| 100 | out: |
| 101 | mutex_unlock(&inode->i_mutex); |
| 102 | return error; |
| 103 | } |
| 104 | EXPORT_SYMBOL_GPL(vfs_setxattr); |
| 105 | |
| 106 | ssize_t |
David P. Quigley | 4249259 | 2008-02-04 22:29:39 -0800 | [diff] [blame] | 107 | xattr_getsecurity(struct inode *inode, const char *name, void *value, |
| 108 | size_t size) |
| 109 | { |
| 110 | void *buffer = NULL; |
| 111 | ssize_t len; |
| 112 | |
| 113 | if (!value || !size) { |
| 114 | len = security_inode_getsecurity(inode, name, &buffer, false); |
| 115 | goto out_noalloc; |
| 116 | } |
| 117 | |
| 118 | len = security_inode_getsecurity(inode, name, &buffer, true); |
| 119 | if (len < 0) |
| 120 | return len; |
| 121 | if (size < len) { |
| 122 | len = -ERANGE; |
| 123 | goto out; |
| 124 | } |
| 125 | memcpy(value, buffer, len); |
| 126 | out: |
| 127 | security_release_secctx(buffer, len); |
| 128 | out_noalloc: |
| 129 | return len; |
| 130 | } |
| 131 | EXPORT_SYMBOL_GPL(xattr_getsecurity); |
| 132 | |
| 133 | ssize_t |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 134 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 135 | { |
| 136 | struct inode *inode = dentry->d_inode; |
| 137 | int error; |
| 138 | |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 139 | error = xattr_permission(inode, name, MAY_READ); |
| 140 | if (error) |
| 141 | return error; |
| 142 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 143 | error = security_inode_getxattr(dentry, name); |
| 144 | if (error) |
| 145 | return error; |
| 146 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 147 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 148 | XATTR_SECURITY_PREFIX_LEN)) { |
| 149 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
David P. Quigley | 4249259 | 2008-02-04 22:29:39 -0800 | [diff] [blame] | 150 | int ret = xattr_getsecurity(inode, suffix, value, size); |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 151 | /* |
| 152 | * Only overwrite the return value if a security module |
| 153 | * is actually active. |
| 154 | */ |
David P. Quigley | 4bea580 | 2008-02-04 22:29:40 -0800 | [diff] [blame] | 155 | if (ret == -EOPNOTSUPP) |
| 156 | goto nolsm; |
| 157 | return ret; |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 158 | } |
David P. Quigley | 4bea580 | 2008-02-04 22:29:40 -0800 | [diff] [blame] | 159 | nolsm: |
| 160 | if (inode->i_op->getxattr) |
| 161 | error = inode->i_op->getxattr(dentry, name, value, size); |
| 162 | else |
| 163 | error = -EOPNOTSUPP; |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 164 | |
| 165 | return error; |
| 166 | } |
| 167 | EXPORT_SYMBOL_GPL(vfs_getxattr); |
| 168 | |
Bill Nottingham | 659564c | 2006-10-09 16:10:48 -0400 | [diff] [blame] | 169 | ssize_t |
| 170 | vfs_listxattr(struct dentry *d, char *list, size_t size) |
| 171 | { |
| 172 | ssize_t error; |
| 173 | |
| 174 | error = security_inode_listxattr(d); |
| 175 | if (error) |
| 176 | return error; |
| 177 | error = -EOPNOTSUPP; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 178 | if (d->d_inode->i_op->listxattr) { |
Bill Nottingham | 659564c | 2006-10-09 16:10:48 -0400 | [diff] [blame] | 179 | error = d->d_inode->i_op->listxattr(d, list, size); |
| 180 | } else { |
| 181 | error = security_inode_listsecurity(d->d_inode, list, size); |
| 182 | if (size && error > size) |
| 183 | error = -ERANGE; |
| 184 | } |
| 185 | return error; |
| 186 | } |
| 187 | EXPORT_SYMBOL_GPL(vfs_listxattr); |
| 188 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 189 | int |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 190 | vfs_removexattr(struct dentry *dentry, const char *name) |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 191 | { |
| 192 | struct inode *inode = dentry->d_inode; |
| 193 | int error; |
| 194 | |
| 195 | if (!inode->i_op->removexattr) |
| 196 | return -EOPNOTSUPP; |
| 197 | |
akpm@osdl.org | e0ad7b0 | 2006-01-09 20:51:56 -0800 | [diff] [blame] | 198 | error = xattr_permission(inode, name, MAY_WRITE); |
| 199 | if (error) |
| 200 | return error; |
| 201 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 202 | error = security_inode_removexattr(dentry, name); |
| 203 | if (error) |
| 204 | return error; |
| 205 | |
| 206 | mutex_lock(&inode->i_mutex); |
| 207 | error = inode->i_op->removexattr(dentry, name); |
| 208 | mutex_unlock(&inode->i_mutex); |
| 209 | |
| 210 | if (!error) |
| 211 | fsnotify_xattr(dentry); |
| 212 | return error; |
| 213 | } |
| 214 | EXPORT_SYMBOL_GPL(vfs_removexattr); |
| 215 | |
| 216 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | /* |
| 218 | * Extended attribute SET operations |
| 219 | */ |
| 220 | static long |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 221 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | size_t size, int flags) |
| 223 | { |
| 224 | int error; |
| 225 | void *kvalue = NULL; |
| 226 | char kname[XATTR_NAME_MAX + 1]; |
| 227 | |
| 228 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) |
| 229 | return -EINVAL; |
| 230 | |
| 231 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 232 | if (error == 0 || error == sizeof(kname)) |
| 233 | error = -ERANGE; |
| 234 | if (error < 0) |
| 235 | return error; |
| 236 | |
| 237 | if (size) { |
| 238 | if (size > XATTR_SIZE_MAX) |
| 239 | return -E2BIG; |
| 240 | kvalue = kmalloc(size, GFP_KERNEL); |
| 241 | if (!kvalue) |
| 242 | return -ENOMEM; |
| 243 | if (copy_from_user(kvalue, value, size)) { |
| 244 | kfree(kvalue); |
| 245 | return -EFAULT; |
| 246 | } |
| 247 | } |
| 248 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 249 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
Jesper Juhl | f99d49a | 2005-11-07 01:01:34 -0800 | [diff] [blame] | 250 | kfree(kvalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | return error; |
| 252 | } |
| 253 | |
| 254 | asmlinkage long |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 255 | sys_setxattr(const char __user *pathname, const char __user *name, |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 256 | const void __user *value, size_t size, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 258 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | int error; |
| 260 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 261 | error = user_path(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | if (error) |
| 263 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 264 | error = mnt_want_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 265 | if (!error) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 266 | error = setxattr(path.dentry, name, value, size, flags); |
| 267 | mnt_drop_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 268 | } |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 269 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | return error; |
| 271 | } |
| 272 | |
| 273 | asmlinkage long |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 274 | sys_lsetxattr(const char __user *pathname, const char __user *name, |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 275 | const void __user *value, size_t size, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 277 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | int error; |
| 279 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 280 | error = user_lpath(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | if (error) |
| 282 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 283 | error = mnt_want_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 284 | if (!error) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 285 | error = setxattr(path.dentry, name, value, size, flags); |
| 286 | mnt_drop_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 287 | } |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 288 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | return error; |
| 290 | } |
| 291 | |
| 292 | asmlinkage long |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 293 | sys_fsetxattr(int fd, const char __user *name, const void __user *value, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | size_t size, int flags) |
| 295 | { |
| 296 | struct file *f; |
Amy Griffis | 73241cc | 2005-11-03 16:00:25 +0000 | [diff] [blame] | 297 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | int error = -EBADF; |
| 299 | |
| 300 | f = fget(fd); |
| 301 | if (!f) |
| 302 | return error; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 303 | dentry = f->f_path.dentry; |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 304 | audit_inode(NULL, dentry); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 305 | error = mnt_want_write(f->f_path.mnt); |
| 306 | if (!error) { |
| 307 | error = setxattr(dentry, name, value, size, flags); |
| 308 | mnt_drop_write(f->f_path.mnt); |
| 309 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | fput(f); |
| 311 | return error; |
| 312 | } |
| 313 | |
| 314 | /* |
| 315 | * Extended attribute GET operations |
| 316 | */ |
| 317 | static ssize_t |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 318 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
| 319 | size_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 320 | { |
| 321 | ssize_t error; |
| 322 | void *kvalue = NULL; |
| 323 | char kname[XATTR_NAME_MAX + 1]; |
| 324 | |
| 325 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 326 | if (error == 0 || error == sizeof(kname)) |
| 327 | error = -ERANGE; |
| 328 | if (error < 0) |
| 329 | return error; |
| 330 | |
| 331 | if (size) { |
| 332 | if (size > XATTR_SIZE_MAX) |
| 333 | size = XATTR_SIZE_MAX; |
James Morris | d381d8a | 2005-10-30 14:59:22 -0800 | [diff] [blame] | 334 | kvalue = kzalloc(size, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | if (!kvalue) |
| 336 | return -ENOMEM; |
| 337 | } |
| 338 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 339 | error = vfs_getxattr(d, kname, kvalue, size); |
Stephen Smalley | f549d6c | 2005-09-03 15:55:18 -0700 | [diff] [blame] | 340 | if (error > 0) { |
| 341 | if (size && copy_to_user(value, kvalue, error)) |
| 342 | error = -EFAULT; |
| 343 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { |
| 344 | /* The file system tried to returned a value bigger |
| 345 | than XATTR_SIZE_MAX bytes. Not possible. */ |
| 346 | error = -E2BIG; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | } |
Jesper Juhl | f99d49a | 2005-11-07 01:01:34 -0800 | [diff] [blame] | 348 | kfree(kvalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | return error; |
| 350 | } |
| 351 | |
| 352 | asmlinkage ssize_t |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 353 | sys_getxattr(const char __user *pathname, const char __user *name, |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 354 | void __user *value, size_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 356 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | ssize_t error; |
| 358 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 359 | error = user_path(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | if (error) |
| 361 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 362 | error = getxattr(path.dentry, name, value, size); |
| 363 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | return error; |
| 365 | } |
| 366 | |
| 367 | asmlinkage ssize_t |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 368 | sys_lgetxattr(const char __user *pathname, const char __user *name, void __user *value, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | size_t size) |
| 370 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 371 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | ssize_t error; |
| 373 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 374 | error = user_lpath(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | if (error) |
| 376 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 377 | error = getxattr(path.dentry, name, value, size); |
| 378 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | return error; |
| 380 | } |
| 381 | |
| 382 | asmlinkage ssize_t |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 383 | sys_fgetxattr(int fd, const char __user *name, void __user *value, size_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | { |
| 385 | struct file *f; |
| 386 | ssize_t error = -EBADF; |
| 387 | |
| 388 | f = fget(fd); |
| 389 | if (!f) |
| 390 | return error; |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 391 | audit_inode(NULL, f->f_path.dentry); |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 392 | error = getxattr(f->f_path.dentry, name, value, size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | fput(f); |
| 394 | return error; |
| 395 | } |
| 396 | |
| 397 | /* |
| 398 | * Extended attribute LIST operations |
| 399 | */ |
| 400 | static ssize_t |
| 401 | listxattr(struct dentry *d, char __user *list, size_t size) |
| 402 | { |
| 403 | ssize_t error; |
| 404 | char *klist = NULL; |
| 405 | |
| 406 | if (size) { |
| 407 | if (size > XATTR_LIST_MAX) |
| 408 | size = XATTR_LIST_MAX; |
| 409 | klist = kmalloc(size, GFP_KERNEL); |
| 410 | if (!klist) |
| 411 | return -ENOMEM; |
| 412 | } |
| 413 | |
Bill Nottingham | 659564c | 2006-10-09 16:10:48 -0400 | [diff] [blame] | 414 | error = vfs_listxattr(d, klist, size); |
Stephen Smalley | f549d6c | 2005-09-03 15:55:18 -0700 | [diff] [blame] | 415 | if (error > 0) { |
| 416 | if (size && copy_to_user(list, klist, error)) |
| 417 | error = -EFAULT; |
| 418 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { |
| 419 | /* The file system tried to returned a list bigger |
| 420 | than XATTR_LIST_MAX bytes. Not possible. */ |
| 421 | error = -E2BIG; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | } |
Jesper Juhl | f99d49a | 2005-11-07 01:01:34 -0800 | [diff] [blame] | 423 | kfree(klist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | return error; |
| 425 | } |
| 426 | |
| 427 | asmlinkage ssize_t |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 428 | sys_listxattr(const char __user *pathname, char __user *list, size_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 430 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | ssize_t error; |
| 432 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 433 | error = user_path(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | if (error) |
| 435 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 436 | error = listxattr(path.dentry, list, size); |
| 437 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | return error; |
| 439 | } |
| 440 | |
| 441 | asmlinkage ssize_t |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 442 | sys_llistxattr(const char __user *pathname, char __user *list, size_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 444 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | ssize_t error; |
| 446 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 447 | error = user_lpath(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | if (error) |
| 449 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 450 | error = listxattr(path.dentry, list, size); |
| 451 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | return error; |
| 453 | } |
| 454 | |
| 455 | asmlinkage ssize_t |
| 456 | sys_flistxattr(int fd, char __user *list, size_t size) |
| 457 | { |
| 458 | struct file *f; |
| 459 | ssize_t error = -EBADF; |
| 460 | |
| 461 | f = fget(fd); |
| 462 | if (!f) |
| 463 | return error; |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 464 | audit_inode(NULL, f->f_path.dentry); |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 465 | error = listxattr(f->f_path.dentry, list, size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | fput(f); |
| 467 | return error; |
| 468 | } |
| 469 | |
| 470 | /* |
| 471 | * Extended attribute REMOVE operations |
| 472 | */ |
| 473 | static long |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 474 | removexattr(struct dentry *d, const char __user *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | { |
| 476 | int error; |
| 477 | char kname[XATTR_NAME_MAX + 1]; |
| 478 | |
| 479 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 480 | if (error == 0 || error == sizeof(kname)) |
| 481 | error = -ERANGE; |
| 482 | if (error < 0) |
| 483 | return error; |
| 484 | |
Christoph Hellwig | 5be196e | 2006-01-09 20:51:55 -0800 | [diff] [blame] | 485 | return vfs_removexattr(d, kname); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | } |
| 487 | |
| 488 | asmlinkage long |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 489 | sys_removexattr(const char __user *pathname, const char __user *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 491 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | int error; |
| 493 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 494 | error = user_path(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | if (error) |
| 496 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 497 | error = mnt_want_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 498 | if (!error) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 499 | error = removexattr(path.dentry, name); |
| 500 | mnt_drop_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 501 | } |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 502 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | return error; |
| 504 | } |
| 505 | |
| 506 | asmlinkage long |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 507 | sys_lremovexattr(const char __user *pathname, const char __user *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 509 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | int error; |
| 511 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 512 | error = user_lpath(pathname, &path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | if (error) |
| 514 | return error; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 515 | error = mnt_want_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 516 | if (!error) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 517 | error = removexattr(path.dentry, name); |
| 518 | mnt_drop_write(path.mnt); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 519 | } |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 520 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | return error; |
| 522 | } |
| 523 | |
| 524 | asmlinkage long |
David Howells | 8f0cfa5 | 2008-04-29 00:59:41 -0700 | [diff] [blame] | 525 | sys_fremovexattr(int fd, const char __user *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | { |
| 527 | struct file *f; |
Amy Griffis | 73241cc | 2005-11-03 16:00:25 +0000 | [diff] [blame] | 528 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | int error = -EBADF; |
| 530 | |
| 531 | f = fget(fd); |
| 532 | if (!f) |
| 533 | return error; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 534 | dentry = f->f_path.dentry; |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 535 | audit_inode(NULL, dentry); |
Dave Hansen | 18f335a | 2008-02-15 14:37:38 -0800 | [diff] [blame] | 536 | error = mnt_want_write(f->f_path.mnt); |
| 537 | if (!error) { |
| 538 | error = removexattr(dentry, name); |
| 539 | mnt_drop_write(f->f_path.mnt); |
| 540 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | fput(f); |
| 542 | return error; |
| 543 | } |
| 544 | |
| 545 | |
| 546 | static const char * |
| 547 | strcmp_prefix(const char *a, const char *a_prefix) |
| 548 | { |
| 549 | while (*a_prefix && *a == *a_prefix) { |
| 550 | a++; |
| 551 | a_prefix++; |
| 552 | } |
| 553 | return *a_prefix ? NULL : a; |
| 554 | } |
| 555 | |
| 556 | /* |
| 557 | * In order to implement different sets of xattr operations for each xattr |
| 558 | * prefix with the generic xattr API, a filesystem should create a |
| 559 | * null-terminated array of struct xattr_handler (one for each prefix) and |
| 560 | * hang a pointer to it off of the s_xattr field of the superblock. |
| 561 | * |
| 562 | * The generic_fooxattr() functions will use this list to dispatch xattr |
| 563 | * operations to the correct xattr_handler. |
| 564 | */ |
| 565 | #define for_each_xattr_handler(handlers, handler) \ |
| 566 | for ((handler) = *(handlers)++; \ |
| 567 | (handler) != NULL; \ |
| 568 | (handler) = *(handlers)++) |
| 569 | |
| 570 | /* |
| 571 | * Find the xattr_handler with the matching prefix. |
| 572 | */ |
| 573 | static struct xattr_handler * |
| 574 | xattr_resolve_name(struct xattr_handler **handlers, const char **name) |
| 575 | { |
| 576 | struct xattr_handler *handler; |
| 577 | |
| 578 | if (!*name) |
| 579 | return NULL; |
| 580 | |
| 581 | for_each_xattr_handler(handlers, handler) { |
| 582 | const char *n = strcmp_prefix(*name, handler->prefix); |
| 583 | if (n) { |
| 584 | *name = n; |
| 585 | break; |
| 586 | } |
| 587 | } |
| 588 | return handler; |
| 589 | } |
| 590 | |
| 591 | /* |
| 592 | * Find the handler for the prefix and dispatch its get() operation. |
| 593 | */ |
| 594 | ssize_t |
| 595 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) |
| 596 | { |
| 597 | struct xattr_handler *handler; |
| 598 | struct inode *inode = dentry->d_inode; |
| 599 | |
| 600 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); |
| 601 | if (!handler) |
| 602 | return -EOPNOTSUPP; |
| 603 | return handler->get(inode, name, buffer, size); |
| 604 | } |
| 605 | |
| 606 | /* |
| 607 | * Combine the results of the list() operation from every xattr_handler in the |
| 608 | * list. |
| 609 | */ |
| 610 | ssize_t |
| 611 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) |
| 612 | { |
| 613 | struct inode *inode = dentry->d_inode; |
| 614 | struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr; |
| 615 | unsigned int size = 0; |
| 616 | |
| 617 | if (!buffer) { |
| 618 | for_each_xattr_handler(handlers, handler) |
| 619 | size += handler->list(inode, NULL, 0, NULL, 0); |
| 620 | } else { |
| 621 | char *buf = buffer; |
| 622 | |
| 623 | for_each_xattr_handler(handlers, handler) { |
| 624 | size = handler->list(inode, buf, buffer_size, NULL, 0); |
| 625 | if (size > buffer_size) |
| 626 | return -ERANGE; |
| 627 | buf += size; |
| 628 | buffer_size -= size; |
| 629 | } |
| 630 | size = buf - buffer; |
| 631 | } |
| 632 | return size; |
| 633 | } |
| 634 | |
| 635 | /* |
| 636 | * Find the handler for the prefix and dispatch its set() operation. |
| 637 | */ |
| 638 | int |
| 639 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) |
| 640 | { |
| 641 | struct xattr_handler *handler; |
| 642 | struct inode *inode = dentry->d_inode; |
| 643 | |
| 644 | if (size == 0) |
| 645 | value = ""; /* empty EA, do not remove */ |
| 646 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); |
| 647 | if (!handler) |
| 648 | return -EOPNOTSUPP; |
| 649 | return handler->set(inode, name, value, size, flags); |
| 650 | } |
| 651 | |
| 652 | /* |
| 653 | * Find the handler for the prefix and dispatch its set() operation to remove |
| 654 | * any associated extended attribute. |
| 655 | */ |
| 656 | int |
| 657 | generic_removexattr(struct dentry *dentry, const char *name) |
| 658 | { |
| 659 | struct xattr_handler *handler; |
| 660 | struct inode *inode = dentry->d_inode; |
| 661 | |
| 662 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); |
| 663 | if (!handler) |
| 664 | return -EOPNOTSUPP; |
| 665 | return handler->set(inode, name, NULL, 0, XATTR_REPLACE); |
| 666 | } |
| 667 | |
| 668 | EXPORT_SYMBOL(generic_getxattr); |
| 669 | EXPORT_SYMBOL(generic_listxattr); |
| 670 | EXPORT_SYMBOL(generic_setxattr); |
| 671 | EXPORT_SYMBOL(generic_removexattr); |