diff options
Diffstat (limited to 'fs/squashfs/xattr.c')
| -rw-r--r-- | fs/squashfs/xattr.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/fs/squashfs/xattr.c b/fs/squashfs/xattr.c new file mode 100644 index 00000000000..c7655e8b31c --- /dev/null +++ b/fs/squashfs/xattr.c @@ -0,0 +1,323 @@ +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2010 + * Phillip Lougher <phillip@lougher.demon.co.uk> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2, + * or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * xattr_id.c + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/string.h> +#include <linux/fs.h> +#include <linux/vfs.h> +#include <linux/xattr.h> +#include <linux/slab.h> + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs_fs_i.h" +#include "squashfs.h" + +static const struct xattr_handler *squashfs_xattr_handler(int); + +ssize_t squashfs_listxattr(struct dentry *d, char *buffer, + size_t buffer_size) +{ + struct inode *inode = d->d_inode; + struct super_block *sb = inode->i_sb; + struct squashfs_sb_info *msblk = sb->s_fs_info; + u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr) + + msblk->xattr_table; + int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr); + int count = squashfs_i(inode)->xattr_count; + size_t rest = buffer_size; + int err; + + /* check that the file system has xattrs */ + if (msblk->xattr_id_table == NULL) + return -EOPNOTSUPP; + + /* loop reading each xattr name */ + while (count--) { + struct squashfs_xattr_entry entry; + struct squashfs_xattr_val val; + const struct xattr_handler *handler; + int name_size, prefix_size = 0; + + err = squashfs_read_metadata(sb, &entry, &start, &offset, + sizeof(entry)); + if (err < 0) + goto failed; + + name_size = le16_to_cpu(entry.size); + handler = squashfs_xattr_handler(le16_to_cpu(entry.type)); + if (handler) + prefix_size = handler->list(d, buffer, rest, NULL, + name_size, handler->flags); + if (prefix_size) { + if (buffer) { + if (prefix_size + name_size + 1 > rest) { + err = -ERANGE; + goto failed; + } + buffer += prefix_size; + } + err = squashfs_read_metadata(sb, buffer, &start, + &offset, name_size); + if (err < 0) + goto failed; + if (buffer) { + buffer[name_size] = '\0'; + buffer += name_size + 1; + } + rest -= prefix_size + name_size + 1; + } else { + /* no handler or insuffficient privileges, so skip */ + err = squashfs_read_metadata(sb, NULL, &start, + &offset, name_size); + if (err < 0) + goto failed; + } + + + /* skip remaining xattr entry */ + err = squashfs_read_metadata(sb, &val, &start, &offset, + sizeof(val)); + if (err < 0) + goto failed; + + err = squashfs_read_metadata(sb, NULL, &start, &offset, + le32_to_cpu(val.vsize)); + if (err < 0) + goto failed; + } + err = buffer_size - rest; + +failed: + return err; +} + + +static int squashfs_xattr_get(struct inode *inode, int name_index, + const char *name, void *buffer, size_t buffer_size) +{ + struct super_block *sb = inode->i_sb; + struct squashfs_sb_info *msblk = sb->s_fs_info; + u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr) + + msblk->xattr_table; + int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr); + int count = squashfs_i(inode)->xattr_count; + int name_len = strlen(name); + int err, vsize; + char *target = kmalloc(name_len, GFP_KERNEL); + + if (target == NULL) + return -ENOMEM; + + /* loop reading each xattr name */ + for (; count; count--) { + struct squashfs_xattr_entry entry; + struct squashfs_xattr_val val; + int type, prefix, name_size; + + err = squashfs_read_metadata(sb, &entry, &start, &offset, + sizeof(entry)); + if (err < 0) + goto failed; + + name_size = le16_to_cpu(entry.size); + type = le16_to_cpu(entry.type); + prefix = type & SQUASHFS_XATTR_PREFIX_MASK; + + if (prefix == name_index && name_size == name_len) + err = squashfs_read_metadata(sb, target, &start, + &offset, name_size); + else + err = squashfs_read_metadata(sb, NULL, &start, + &offset, name_size); + if (err < 0) + goto failed; + + if (prefix == name_index && name_size == name_len && + strncmp(target, name, name_size) == 0) { + /* found xattr */ + if (type & SQUASHFS_XATTR_VALUE_OOL) { + __le64 xattr; + /* val is a reference to the real location */ + err = squashfs_read_metadata(sb, &val, &start, + &offset, sizeof(val)); + if (err < 0) + goto failed; + err = squashfs_read_metadata(sb, &xattr, &start, + &offset, sizeof(xattr)); + if (err < 0) + goto failed; + xattr = le64_to_cpu(xattr); + start = SQUASHFS_XATTR_BLK(xattr) + + msblk->xattr_table; + offset = SQUASHFS_XATTR_OFFSET(xattr); + } + /* read xattr value */ + err = squashfs_read_metadata(sb, &val, &start, &offset, + sizeof(val)); + if (err < 0) + goto failed; + + vsize = le32_to_cpu(val.vsize); + if (buffer) { + if (vsize > buffer_size) { + err = -ERANGE; + goto failed; + } + err = squashfs_read_metadata(sb, buffer, &start, + &offset, vsize); + if (err < 0) + goto failed; + } + break; + } + + /* no match, skip remaining xattr entry */ + err = squashfs_read_metadata(sb, &val, &start, &offset, + sizeof(val)); + if (err < 0) + goto failed; + err = squashfs_read_metadata(sb, NULL, &start, &offset, + le32_to_cpu(val.vsize)); + if (err < 0) + goto failed; + } + err = count ? vsize : -ENODATA; + +failed: + kfree(target); + return err; +} + + +/* + * User namespace support + */ +static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size, + const char *name, size_t name_len, int type) +{ + if (list && XATTR_USER_PREFIX_LEN <= list_size) + memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); + return XATTR_USER_PREFIX_LEN; +} + +static int squashfs_user_get(struct dentry *d, const char *name, void *buffer, + size_t size, int type) +{ + if (name[0] == '\0') + return -EINVAL; + + return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name, + buffer, size); +} + +static const struct xattr_handler squashfs_xattr_user_handler = { + .prefix = XATTR_USER_PREFIX, + .list = squashfs_user_list, + .get = squashfs_user_get +}; + +/* + * Trusted namespace support + */ +static size_t squashfs_trusted_list(struct dentry *d, char *list, + size_t list_size, const char *name, size_t name_len, int type) +{ + if (!capable(CAP_SYS_ADMIN)) + return 0; + + if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size) + memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); + return XATTR_TRUSTED_PREFIX_LEN; +} + +static int squashfs_trusted_get(struct dentry *d, const char *name, + void *buffer, size_t size, int type) +{ + if (name[0] == '\0') + return -EINVAL; + + return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name, + buffer, size); +} + +static const struct xattr_handler squashfs_xattr_trusted_handler = { + .prefix = XATTR_TRUSTED_PREFIX, + .list = squashfs_trusted_list, + .get = squashfs_trusted_get +}; + +/* + * Security namespace support + */ +static size_t squashfs_security_list(struct dentry *d, char *list, + size_t list_size, const char *name, size_t name_len, int type) +{ + if (list && XATTR_SECURITY_PREFIX_LEN <= list_size) + memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); + return XATTR_SECURITY_PREFIX_LEN; +} + +static int squashfs_security_get(struct dentry *d, const char *name, + void *buffer, size_t size, int type) +{ + if (name[0] == '\0') + return -EINVAL; + + return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name, + buffer, size); +} + +static const struct xattr_handler squashfs_xattr_security_handler = { + .prefix = XATTR_SECURITY_PREFIX, + .list = squashfs_security_list, + .get = squashfs_security_get +}; + +static inline const struct xattr_handler *squashfs_xattr_handler(int type) +{ + if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL)) + /* ignore unrecognised type */ + return NULL; + + switch (type & SQUASHFS_XATTR_PREFIX_MASK) { + case SQUASHFS_XATTR_USER: + return &squashfs_xattr_user_handler; + case SQUASHFS_XATTR_TRUSTED: + return &squashfs_xattr_trusted_handler; + case SQUASHFS_XATTR_SECURITY: + return &squashfs_xattr_security_handler; + default: + /* ignore unrecognised type */ + return NULL; + } +} + +const struct xattr_handler *squashfs_xattr_handlers[] = { + &squashfs_xattr_user_handler, + &squashfs_xattr_trusted_handler, + &squashfs_xattr_security_handler, + NULL +}; + |