path: root/fs/hfsplus/xattr.c

/*
 * linux/fs/hfsplus/xattr.c
 *
 * Vyacheslav Dubeyko <slava@dubeyko.com>
 *
 * Logic of processing extended attributes
 */

#include "hfsplus_fs.h"
#include "xattr.h"
#include "acl.h"

const struct xattr_handler *hfsplus_xattr_handlers[] = {
	&hfsplus_xattr_osx_handler,
	&hfsplus_xattr_user_handler,
	&hfsplus_xattr_trusted_handler,
#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
	&hfsplus_xattr_acl_access_handler,
	&hfsplus_xattr_acl_default_handler,
#endif
	&hfsplus_xattr_security_handler,
	NULL
};

static int strcmp_xattr_finder_info(const char *name)
{
	if (name) {
		return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
				sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
	}
	return -1;
}

static int strcmp_xattr_acl(const char *name)
{
	if (name) {
		return strncmp(name, HFSPLUS_XATTR_ACL_NAME,
				sizeof(HFSPLUS_XATTR_ACL_NAME));
	}
	return -1;
}

static inline int is_known_namespace(const char *name)
{
	if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
	    strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
	    strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
	    strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
		return false;

	return true;
}

static int can_set_system_xattr(struct inode *inode, const char *name,
				const void *value, size_t size)
{
#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
	struct posix_acl *acl;
	int err;

	if (!inode_owner_or_capable(inode))
		return -EPERM;

	/*
	 * POSIX_ACL_XATTR_ACCESS is tied to i_mode
	 */
	if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
		acl = posix_acl_from_xattr(&init_user_ns, value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		if (acl) {
			err = posix_acl_equiv_mode(acl, &inode->i_mode);
			posix_acl_release(acl);
			if (err < 0)
				return err;
			mark_inode_dirty(inode);
		}
		/*
		 * We're changing the ACL.  Get rid of the cached one
		 */
		forget_cached_acl(inode, ACL_TYPE_ACCESS);

		return 0;
	} else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
		acl = posix_acl_from_xattr(&init_user_ns, value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		posix_acl_release(acl);

		/*
		 * We're changing the default ACL.  Get rid of the cached one
		 */
		forget_cached_acl(inode, ACL_TYPE_DEFAULT);

		return 0;
	}
#endif /* CONFIG_HFSPLUS_FS_POSIX_ACL */
	return -EOPNOTSUPP;
}

static int can_set_xattr(struct inode *inode, const char *name,
				const void *value, size_t value_len)
{
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return can_set_system_xattr(inode, name, value, value_len);

	if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
		/*
		 * This makes sure that we aren't trying to set an
		 * attribute in a different namespace by prefixing it
		 * with "osx."
		 */
		if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
			return -EOPNOTSUPP;

		return 0;
	}

	/*
	 * Don't allow setting an attribute in an unknown namespace.
	 */
	if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
	    strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
	    strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
		return -EOPNOTSUPP;

	return 0;
}

static void hfsplus_init_header_node(struct inode *attr_file,
					u32 clump_size,
					char *buf, u16 node_size)
{
	struct hfs_bnode_desc *desc;
	struct hfs_btree_header_rec *head;
	u16 offset;
	__be16 *rec_offsets;
	u32 hdr_node_map_rec_bits;
	char *bmp;
	u32 used_nodes;
	u32 used_bmp_bytes;
	loff_t tmp;

	hfs_dbg(ATTR_MOD, "init_hdr_attr_file: clump %u, node_size %u\n",
				clump_size, node_size);

	/* The end of the node contains list of record offsets */
	rec_offsets = (__be16 *)(buf + node_size);

	desc = (struct hfs_bnode_desc *)buf;
	desc->type = HFS_NODE_HEADER;
	desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT);
	offset = sizeof(struct hfs_bnode_desc);
	*--rec_offsets = cpu_to_be16(offset);

	head = (struct hfs_btree_header_rec *)(buf + offset);
	head->node_size = cpu_to_be16(node_size);
	tmp = i_size_read(attr_file);
	do_div(tmp, node_size);
	head->node_count = cpu_to_be32(tmp);
	head->free_nodes =