[linux.git] / fs / fuse / acl.c

/*
 * FUSE: Filesystem in Userspace
 * Copyright (C) 2016 Canonical Ltd. <[email protected]>
 *
 * This program can be distributed under the terms of the GNU GPL.
 * See the file COPYING.
 */

#include "fuse_i.h"

#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>

struct posix_acl *fuse_get_acl(struct inode *inode, int type)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	int size;
	const char *name;
	void *value = NULL;
	struct posix_acl *acl;

	if (fuse_is_bad(inode))
		return ERR_PTR(-EIO);

	if (!fc->posix_acl || fc->no_getxattr)
		return NULL;

	if (type == ACL_TYPE_ACCESS)
		name = XATTR_NAME_POSIX_ACL_ACCESS;
	else if (type == ACL_TYPE_DEFAULT)
		name = XATTR_NAME_POSIX_ACL_DEFAULT;
	else
		return ERR_PTR(-EOPNOTSUPP);

	value = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!value)
		return ERR_PTR(-ENOMEM);
	size = fuse_getxattr(inode, name, value, PAGE_SIZE);
	if (size > 0)
		acl = posix_acl_from_xattr(fc->user_ns, value, size);
	else if ((size == 0) || (size == -ENODATA) ||
		 (size == -EOPNOTSUPP && fc->no_getxattr))
		acl = NULL;
	else if (size == -ERANGE)
		acl = ERR_PTR(-E2BIG);
	else
		acl = ERR_PTR(size);

	kfree(value);
	return acl;
}

int fuse_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
		 struct posix_acl *acl, int type)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	const char *name;
	int ret;

	if (fuse_is_bad(inode))
		return -EIO;

	if (!fc->posix_acl || fc->no_setxattr)
		return -EOPNOTSUPP;

	if (type == ACL_TYPE_ACCESS)
		name = XATTR_NAME_POSIX_ACL_ACCESS;
	else if (type == ACL_TYPE_DEFAULT)
		name = XATTR_NAME_POSIX_ACL_DEFAULT;
	else
		return -EINVAL;

	if (acl) {
		unsigned int extra_flags = 0;
		/*
		 * Fuse userspace is responsible for updating access
		 * permissions in the inode, if needed. fuse_setxattr
		 * invalidates the inode attributes, which will force
		 * them to be refreshed the next time they are used,
		 * and it also updates i_ctime.
		 */
		size_t size = posix_acl_xattr_size(acl->a_count);
		void *value;

		if (size > PAGE_SIZE)
			return -E2BIG;

		value = kmalloc(size, GFP_KERNEL);
		if (!value)
			return -ENOMEM;

		ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
		if (ret < 0) {
			kfree(value);
			return ret;
		}

		if (!in_group_p(i_gid_into_mnt(&init_user_ns, inode)) &&
		    !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID))
			extra_flags |= FUSE_SETXATTR_ACL_KILL_SGID;

		ret = fuse_setxattr(inode, name, value, size, 0, extra_flags);
		kfree(value);
	} else {
		ret = fuse_removexattr(inode, name);
	}
	forget_all_cached_acls(inode);
	fuse_invalidate_attr(inode);

	return ret;
}
Commit	Line	Data
60bcc88a SF	1	/*
	2	* FUSE: Filesystem in Userspace
	3	* Copyright (C) 2016 Canonical Ltd. <[email protected]>
	4	*
	5	* This program can be distributed under the terms of the GNU GPL.
	6	* See the file COPYING.
	7	*/
	8
	9	#include "fuse_i.h"
	10
	11	#include <linux/posix_acl.h>
	12	#include <linux/posix_acl_xattr.h>
	13
	14	struct posix_acl fuse_get_acl(struct inode inode, int type)
	15	{
	16	struct fuse_conn *fc = get_fuse_conn(inode);
	17	int size;
	18	const char *name;
	19	void *value = NULL;
	20	struct posix_acl *acl;
	21
5d069dbe MS	22	if (fuse_is_bad(inode))
	23	return ERR_PTR(-EIO);
	24
60bcc88a SF	25	if (!fc->posix_acl \|\| fc->no_getxattr)
	26	return NULL;
	27
	28	if (type == ACL_TYPE_ACCESS)
	29	name = XATTR_NAME_POSIX_ACL_ACCESS;
	30	else if (type == ACL_TYPE_DEFAULT)
	31	name = XATTR_NAME_POSIX_ACL_DEFAULT;
	32	else
	33	return ERR_PTR(-EOPNOTSUPP);
	34
	35	value = kmalloc(PAGE_SIZE, GFP_KERNEL);
	36	if (!value)
	37	return ERR_PTR(-ENOMEM);
	38	size = fuse_getxattr(inode, name, value, PAGE_SIZE);
	39	if (size > 0)
8cb08329	40	acl = posix_acl_from_xattr(fc->user_ns, value, size);
60bcc88a SF	41	else if ((size == 0) \|\| (size == -ENODATA) \|\|
	42	(size == -EOPNOTSUPP && fc->no_getxattr))
	43	acl = NULL;
	44	else if (size == -ERANGE)
	45	acl = ERR_PTR(-E2BIG);
	46	else
	47	acl = ERR_PTR(size);
	48
	49	kfree(value);
	50	return acl;
	51	}
	52
549c7297 CB	53	int fuse_set_acl(struct user_namespace mnt_userns, struct inode inode,
549c7297 CB	54	struct posix_acl *acl, int type)
60bcc88a SF	55	{
	56	struct fuse_conn *fc = get_fuse_conn(inode);
	57	const char *name;
	58	int ret;
	59
5d069dbe MS	60	if (fuse_is_bad(inode))
	61	return -EIO;
	62
60bcc88a SF	63	if (!fc->posix_acl \|\| fc->no_setxattr)
	64	return -EOPNOTSUPP;
	65
	66	if (type == ACL_TYPE_ACCESS)
	67	name = XATTR_NAME_POSIX_ACL_ACCESS;
	68	else if (type == ACL_TYPE_DEFAULT)
	69	name = XATTR_NAME_POSIX_ACL_DEFAULT;
	70	else
	71	return -EINVAL;
	72
	73	if (acl) {
550a7d3b	74	unsigned int extra_flags = 0;
60bcc88a SF	75	/*
	76	* Fuse userspace is responsible for updating access
	77	* permissions in the inode, if needed. fuse_setxattr
	78	* invalidates the inode attributes, which will force
	79	* them to be refreshed the next time they are used,
	80	* and it also updates i_ctime.
	81	*/
	82	size_t size = posix_acl_xattr_size(acl->a_count);
	83	void *value;
	84
	85	if (size > PAGE_SIZE)
	86	return -E2BIG;
	87
	88	value = kmalloc(size, GFP_KERNEL);
	89	if (!value)
	90	return -ENOMEM;
	91
8cb08329	92	ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
60bcc88a SF	93	if (ret < 0) {
	94	kfree(value);
	95	return ret;
	96	}
	97
550a7d3b VG	98	if (!in_group_p(i_gid_into_mnt(&init_user_ns, inode)) &&
	99	!capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID))
	100	extra_flags \|= FUSE_SETXATTR_ACL_KILL_SGID;
	101
	102	ret = fuse_setxattr(inode, name, value, size, 0, extra_flags);
60bcc88a SF	103	kfree(value);
	104	} else {
	105	ret = fuse_removexattr(inode, name);
	106	}
	107	forget_all_cached_acls(inode);
	108	fuse_invalidate_attr(inode);
	109
	110	return ret;
	111	}