| /* |
| * 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.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; |
| u64 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_val, |
| &start, &offset, sizeof(xattr_val)); |
| if (err < 0) |
| goto failed; |
| xattr = le64_to_cpu(xattr_val); |
| 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 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 |
| }; |
| |