fs/xfs/xfs_acl.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2008, Christoph Hellwig
  * All Rights Reserved.
  */
 #include "xfs.h"
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_attr.h"
 #include "xfs_trace.h"
 #include "xfs_error.h"
 #include "xfs_acl.h"
 #include "xfs_trans.h"
 #include "xfs_xattr.h"

 #include <linux/posix_acl_xattr.h>

 /*
  * Locking scheme:
  *  - all ACL updates are protected by inode->i_mutex, which is taken before
  *    calling into this file.
  */

 STATIC struct posix_acl *
 xfs_acl_from_disk(
 	struct xfs_mount	*mp,
 	const struct xfs_acl	*aclp,
 	int			len,
 	int			max_entries)
 {
 	struct posix_acl_entry *acl_e;
 	struct posix_acl *acl;
 	const struct xfs_acl_entry *ace;
 	unsigned int count, i;

 	if (len < sizeof(*aclp)) {
 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
 				len);
 		return ERR_PTR(-EFSCORRUPTED);
 	}

 	count = be32_to_cpu(aclp->acl_cnt);
 	if (count > max_entries || XFS_ACL_SIZE(count) != len) {
 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
 				len);
 		return ERR_PTR(-EFSCORRUPTED);
 	}

 	acl = posix_acl_alloc(count, GFP_KERNEL);
 	if (!acl)
 		return ERR_PTR(-ENOMEM);

 	for (i = 0; i < count; i++) {
 		acl_e = &acl->a_entries[i];
 		ace = &aclp->acl_entry[i];

 		/*
 		 * The tag is 32 bits on disk and 16 bits in core.
 		 *
 		 * Because every access to it goes through the core
 		 * format first this is not a problem.
 		 */
 		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
 		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

 		switch (acl_e->e_tag) {
 		case ACL_USER:
 			acl_e->e_uid = make_kuid(&init_user_ns,
 						 be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_GROUP:
 			acl_e->e_gid = make_kgid(&init_user_ns,
 						 be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_USER_OBJ:
 		case ACL_GROUP_OBJ:
 		case ACL_MASK:
 		case ACL_OTHER:
 			break;
 		default:
 			goto fail;
 		}
 	}
 	return acl;

 fail:
 	posix_acl_release(acl);
 	return ERR_PTR(-EINVAL);
 }

 STATIC void
 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 {
 	const struct posix_acl_entry *acl_e;
 	struct xfs_acl_entry *ace;
 	int i;

 	aclp->acl_cnt = cpu_to_be32(acl->a_count);
 	for (i = 0; i < acl->a_count; i++) {
 		ace = &aclp->acl_entry[i];
 		acl_e = &acl->a_entries[i];

 		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
 		switch (acl_e->e_tag) {
 		case ACL_USER:
 			ace->ae_id = cpu_to_be32(
 					from_kuid(&init_user_ns, acl_e->e_uid));
 			break;
 		case ACL_GROUP:
 			ace->ae_id = cpu_to_be32(
 					from_kgid(&init_user_ns, acl_e->e_gid));
 			break;
 		default:
 			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
 			break;
 		}

 		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
 	}
 }

 struct posix_acl *
 xfs_get_acl(struct inode *inode, int type, bool rcu)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
 	struct posix_acl	*acl = NULL;
 	struct xfs_da_args	args = {
 		.dp		= ip,
 		.attr_filter	= XFS_ATTR_ROOT,
 		.valuelen	= XFS_ACL_MAX_SIZE(mp),
 	};
 	int			error;

 	if (rcu)
 		return ERR_PTR(-ECHILD);

 	trace_xfs_get_acl(ip);

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		args.name = SGI_ACL_FILE;
 		break;
 	case ACL_TYPE_DEFAULT:
 		args.name = SGI_ACL_DEFAULT;
 		break;
 	default:
 		BUG();
 	}
 	args.namelen = strlen(args.name);

 	/*
 	 * If the attribute doesn't exist make sure we have a negative cache
 	 * entry, for any other error assume it is transient.
 	 */
 	error = xfs_attr_get(&args);
 	if (!error) {
 		acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
 					XFS_ACL_MAX_ENTRIES(mp));
 	} else if (error != -ENOATTR) {
 		acl = ERR_PTR(error);
 	}

 	kmem_free(args.value);
 	return acl;
 }

 int
 __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_da_args	args = {
 		.dp		= ip,
 		.attr_filter	= XFS_ATTR_ROOT,
 	};
 	int			error;

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		args.name = SGI_ACL_FILE;
 		break;
 	case ACL_TYPE_DEFAULT:
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EACCES : 0;
 		args.name = SGI_ACL_DEFAULT;
 		break;
 	default:
 		return -EINVAL;
 	}
 	args.namelen = strlen(args.name);

 	if (acl) {
 		args.valuelen = XFS_ACL_SIZE(acl->a_count);
 		args.value = kvzalloc(args.valuelen, GFP_KERNEL);
 		if (!args.value)
 			return -ENOMEM;
 		xfs_acl_to_disk(args.value, acl);
 	}

 	error = xfs_attr_change(&args);
 	kmem_free(args.value);

 	/*
 	 * If the attribute didn't exist to start with that's fine.
 	 */
 	if (!acl && error == -ENOATTR)
 		error = 0;
 	if (!error)
 		set_cached_acl(inode, type, acl);
 	return error;
 }

 static int
 xfs_acl_set_mode(
 	struct inode		*inode,
 	umode_t			mode)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_trans	*tp;
 	int			error;

 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
 	if (error)
 		return error;

 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	inode->i_mode = mode;
 	inode->i_ctime = current_time(inode);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

 	if (xfs_has_wsync(mp))
 		xfs_trans_set_sync(tp);
 	return xfs_trans_commit(tp);
 }

 int
 xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 	    struct posix_acl *acl, int type)
 {
 	umode_t mode;
 	bool set_mode = false;
 	int error = 0;

 	if (!acl)
 		goto set_acl;

 	error = -E2BIG;
 	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
 		return error;

 	if (type == ACL_TYPE_ACCESS) {
 		error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
 		if (error)
 			return error;
 		set_mode = true;
 	}

  set_acl:
 	/*
 	 * We set the mode after successfully updating the ACL xattr because the
 	 * xattr update can fail at ENOSPC and we don't want to change the mode
 	 * if the ACL update hasn't been applied.
 	 */
 	error =  __xfs_set_acl(inode, acl, type);
 	if (!error && set_mode && mode != inode->i_mode)
 		error = xfs_acl_set_mode(inode, mode);
 	return error;
 }

 /*
  * Invalidate any cached ACLs if the user has bypassed the ACL interface.
  * We don't validate the content whatsoever so it is caller responsibility to
  * provide data in valid format and ensure i_mode is consistent.
  */
 void
 xfs_forget_acl(
 	struct inode		*inode,
 	const char		*name)
 {
 	if (!strcmp(name, SGI_ACL_FILE))
 		forget_cached_acl(inode, ACL_TYPE_ACCESS);
 	else if (!strcmp(name, SGI_ACL_DEFAULT))
 		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (c) 2008, Christoph Hellwig
	* All Rights Reserved.
	*/
	#include "xfs.h"
	#include "xfs_shared.h"
	#include "xfs_format.h"
	#include "xfs_log_format.h"
	#include "xfs_trans_resv.h"
	#include "xfs_mount.h"
	#include "xfs_inode.h"
	#include "xfs_da_format.h"
	#include "xfs_da_btree.h"
	#include "xfs_attr.h"
	#include "xfs_trace.h"
	#include "xfs_error.h"
	#include "xfs_acl.h"
	#include "xfs_trans.h"
	#include "xfs_xattr.h"

	#include <linux/posix_acl_xattr.h>

	/*
	* Locking scheme:
	* - all ACL updates are protected by inode->i_mutex, which is taken before
	* calling into this file.
	*/

	STATIC struct posix_acl *
	xfs_acl_from_disk(
	struct xfs_mount *mp,
	const struct xfs_acl *aclp,
	int len,
	int max_entries)
	{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	const struct xfs_acl_entry *ace;
	unsigned int count, i;

	if (len < sizeof(*aclp)) {
	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	len);
	return ERR_PTR(-EFSCORRUPTED);
	}

	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len) {
	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	len);
	return ERR_PTR(-EFSCORRUPTED);
	}

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
	return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
	acl_e = &acl->a_entries[i];
	ace = &aclp->acl_entry[i];

	/*
	* The tag is 32 bits on disk and 16 bits in core.
	*
	* Because every access to it goes through the core
	* format first this is not a problem.
	*/
	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	acl_e->e_perm = be16_to_cpu(ace->ae_perm);

	switch (acl_e->e_tag) {
	case ACL_USER:
	acl_e->e_uid = make_kuid(&init_user_ns,
	be32_to_cpu(ace->ae_id));
	break;
	case ACL_GROUP:
	acl_e->e_gid = make_kgid(&init_user_ns,
	be32_to_cpu(ace->ae_id));
	break;
	case ACL_USER_OBJ:
	case ACL_GROUP_OBJ:
	case ACL_MASK:
	case ACL_OTHER:
	break;
	default:
	goto fail;
	}
	}
	return acl;

	fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
	}

	STATIC void
	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
	ace = &aclp->acl_entry[i];
	acl_e = &acl->a_entries[i];

	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
	switch (acl_e->e_tag) {
	case ACL_USER:
	ace->ae_id = cpu_to_be32(
	from_kuid(&init_user_ns, acl_e->e_uid));
	break;
	case ACL_GROUP:
	ace->ae_id = cpu_to_be32(
	from_kgid(&init_user_ns, acl_e->e_gid));
	break;
	default:
	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	break;
	}

	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
	}

	struct posix_acl *
	xfs_get_acl(struct inode *inode, int type, bool rcu)
	{
	struct xfs_inode *ip = XFS_I(inode);
	struct xfs_mount *mp = ip->i_mount;
	struct posix_acl *acl = NULL;
	struct xfs_da_args args = {
	.dp = ip,
	.attr_filter = XFS_ATTR_ROOT,
	.valuelen = XFS_ACL_MAX_SIZE(mp),
	};
	int error;

	if (rcu)
	return ERR_PTR(-ECHILD);

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
	args.name = SGI_ACL_FILE;
	break;
	case ACL_TYPE_DEFAULT:
	args.name = SGI_ACL_DEFAULT;
	break;
	default:
	BUG();
	}
	args.namelen = strlen(args.name);

	/*
	* If the attribute doesn't exist make sure we have a negative cache
	* entry, for any other error assume it is transient.
	*/
	error = xfs_attr_get(&args);
	if (!error) {
	acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
	XFS_ACL_MAX_ENTRIES(mp));
	} else if (error != -ENOATTR) {
	acl = ERR_PTR(error);
	}

	kmem_free(args.value);
	return acl;
	}

	int
	__xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
	{
	struct xfs_inode *ip = XFS_I(inode);
	struct xfs_da_args args = {
	.dp = ip,
	.attr_filter = XFS_ATTR_ROOT,
	};
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
	args.name = SGI_ACL_FILE;
	break;
	case ACL_TYPE_DEFAULT:
	if (!S_ISDIR(inode->i_mode))
	return acl ? -EACCES : 0;
	args.name = SGI_ACL_DEFAULT;
	break;
	default:
	return -EINVAL;
	}
	args.namelen = strlen(args.name);

	if (acl) {
	args.valuelen = XFS_ACL_SIZE(acl->a_count);
	args.value = kvzalloc(args.valuelen, GFP_KERNEL);
	if (!args.value)
	return -ENOMEM;
	xfs_acl_to_disk(args.value, acl);
	}

	error = xfs_attr_change(&args);
	kmem_free(args.value);

	/*
	* If the attribute didn't exist to start with that's fine.
	*/
	if (!acl && error == -ENOATTR)
	error = 0;
	if (!error)
	set_cached_acl(inode, type, acl);
	return error;
	}

	static int
	xfs_acl_set_mode(
	struct inode *inode,
	umode_t mode)
	{
	struct xfs_inode *ip = XFS_I(inode);
	struct xfs_mount *mp = ip->i_mount;
	struct xfs_trans *tp;
	int error;

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	if (error)
	return error;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	inode->i_mode = mode;
	inode->i_ctime = current_time(inode);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	if (xfs_has_wsync(mp))
	xfs_trans_set_sync(tp);
	return xfs_trans_commit(tp);
	}

	int
	xfs_set_acl(struct user_namespace mnt_userns, struct inode inode,
	struct posix_acl *acl, int type)
	{
	umode_t mode;
	bool set_mode = false;
	int error = 0;

	if (!acl)
	goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
	return error;

	if (type == ACL_TYPE_ACCESS) {
	error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
	if (error)
	return error;
	set_mode = true;
	}

	set_acl:
	/*
	* We set the mode after successfully updating the ACL xattr because the
	* xattr update can fail at ENOSPC and we don't want to change the mode
	* if the ACL update hasn't been applied.
	*/
	error = __xfs_set_acl(inode, acl, type);
	if (!error && set_mode && mode != inode->i_mode)
	error = xfs_acl_set_mode(inode, mode);
	return error;
	}

	/*
	* Invalidate any cached ACLs if the user has bypassed the ACL interface.
	* We don't validate the content whatsoever so it is caller responsibility to
	* provide data in valid format and ensure i_mode is consistent.
	*/
	void
	xfs_forget_acl(
	struct inode *inode,
	const char *name)
	{
	if (!strcmp(name, SGI_ACL_FILE))
	forget_cached_acl(inode, ACL_TYPE_ACCESS);
	else if (!strcmp(name, SGI_ACL_DEFAULT))
	forget_cached_acl(inode, ACL_TYPE_DEFAULT);
	}