// SPDX-License-Identifier: GPL-2.0/* * linux/fs/ext2/acl.c * * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> */ #include <linux/init.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/fs.h>#include "ext2.h"#include "xattr.h"#include "acl.h" /* * Convert from filesystem to in-memory representation. */static struct posix_acl *ext2_acl_from_disk(const void *value, size_t size){	const char *end = (char *)value + size;	int n, count;	struct posix_acl *acl; 	if (!value)		return NULL;	if (size < sizeof(ext2_acl_header))		 return ERR_PTR(-EINVAL);	if (((ext2_acl_header *)value)->a_version !=	    cpu_to_le32(EXT2_ACL_VERSION))		return ERR_PTR(-EINVAL);	value = (char *)value + sizeof(ext2_acl_header);	count = ext2_acl_count(size);	if (count < 0)		return ERR_PTR(-EINVAL);	if (count == 0)		return NULL;	acl = posix_acl_alloc(count, GFP_KERNEL);	if (!acl)		return ERR_PTR(-ENOMEM);	for (n=0; n < count; n++) {		ext2_acl_entry *entry =			(ext2_acl_entry *)value;		if ((char *)value + sizeof(ext2_acl_entry_short) > end)			goto fail;		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);		switch(acl->a_entries[n].e_tag) {			case ACL_USER_OBJ:			case ACL_GROUP_OBJ:			case ACL_MASK:			case ACL_OTHER:				value = (char *)value +					sizeof(ext2_acl_entry_short);				break; 			case ACL_USER:				value = (char *)value + sizeof(ext2_acl_entry);				if ((char *)value > end)					goto fail;				acl->a_entries[n].e_uid =					make_kuid(&init_user_ns,						  le32_to_cpu(entry->e_id));				break;			case ACL_GROUP:				value = (char *)value + sizeof(ext2_acl_entry);				if ((char *)value > end)					goto fail;				acl->a_entries[n].e_gid =					make_kgid(&init_user_ns,						  le32_to_cpu(entry->e_id));				break; 			default:				goto fail;		}	}	if (value != end)		goto fail;	return acl; fail:	posix_acl_release(acl);	return ERR_PTR(-EINVAL);} /* * Convert from in-memory to filesystem representation. */static void *ext2_acl_to_disk(const struct posix_acl *acl, size_t *size){	ext2_acl_header *ext_acl;	char *e;	size_t n; 	*size = ext2_acl_size(acl->a_count);	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *			sizeof(ext2_acl_entry), GFP_KERNEL);	if (!ext_acl)		return ERR_PTR(-ENOMEM);	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);	e = (char *)ext_acl + sizeof(ext2_acl_header);	for (n=0; n < acl->a_count; n++) {		const struct posix_acl_entry *acl_e = &acl->a_entries[n];		ext2_acl_entry *entry = (ext2_acl_entry *)e;		entry->e_tag  = cpu_to_le16(acl_e->e_tag);		entry->e_perm = cpu_to_le16(acl_e->e_perm);		switch(acl_e->e_tag) {			case ACL_USER:				entry->e_id = cpu_to_le32(					from_kuid(&init_user_ns, acl_e->e_uid));				e += sizeof(ext2_acl_entry);				break;			case ACL_GROUP:				entry->e_id = cpu_to_le32(					from_kgid(&init_user_ns, acl_e->e_gid));				e += sizeof(ext2_acl_entry);				break; 			case ACL_USER_OBJ:			case ACL_GROUP_OBJ:			case ACL_MASK:			case ACL_OTHER:				e += sizeof(ext2_acl_entry_short);				break; 			default:				goto fail;		}	}	return (char *)ext_acl; fail:	kfree(ext_acl);	return ERR_PTR(-EINVAL);} /* * inode->i_mutex: don't care */struct posix_acl *ext2_get_acl(struct inode *inode, int type, bool rcu){	int name_index;	char *value = NULL;	struct posix_acl *acl;	int retval; 	if (rcu)		return ERR_PTR(-ECHILD); 	switch (type) {	case ACL_TYPE_ACCESS:		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;		break;	case ACL_TYPE_DEFAULT:		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;		break;	default:		BUG();	}	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);	if (retval > 0) {		value = kmalloc(retval, GFP_KERNEL);		if (!value)			return ERR_PTR(-ENOMEM);		retval = ext2_xattr_get(inode, name_index, "", value, retval);	}	if (retval > 0)		acl = ext2_acl_from_disk(value, retval);	else if (retval == -ENODATA || retval == -ENOSYS)		acl = NULL;	else		acl = ERR_PTR(retval);	kfree(value); 	return acl;} static int__ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type){	int name_index;	void *value = NULL;	size_t size = 0;	int error; 	switch(type) {		case ACL_TYPE_ACCESS:			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;			break; 		case ACL_TYPE_DEFAULT:			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;			if (!S_ISDIR(inode->i_mode))				return acl ? -EACCES : 0;			break; 		default:			return -EINVAL;	} 	if (acl) {		value = ext2_acl_to_disk(acl, &size);		if (IS_ERR(value))			return (int)PTR_ERR(value);	} 	error = ext2_xattr_set(inode, name_index, "", value, size, 0); 	kfree(value);	if (!error)		set_cached_acl(inode, type, acl);	return error;} /* * inode->i_mutex: down */intext2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,	     struct posix_acl *acl, int type){	int error;	int update_mode = 0;	struct inode *inode = d_inode(dentry);	umode_t mode = inode->i_mode; 	if (type == ACL_TYPE_ACCESS && acl) {		error = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode,					      &acl);		if (error)			return error;		update_mode = 1;	}	error = __ext2_set_acl(inode, acl, type);	if (!error && update_mode) {		inode->i_mode = mode;		inode_set_ctime_current(inode);		mark_inode_dirty(inode);	}	return error;} /* * Initialize the ACLs of a new inode. Called from ext2_new_inode. * * dir->i_mutex: down * inode->i_mutex: up (access to inode is still exclusive) */intext2_init_acl(struct inode *inode, struct inode *dir){	struct posix_acl *default_acl, *acl;	int error; 	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);	if (error)		return error; 	if (default_acl) {		error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);		posix_acl_release(default_acl);	} else {		inode->i_default_acl = NULL;	}	if (acl) {		if (!error)			error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);		posix_acl_release(acl);	} else {		inode->i_acl = NULL;	}	return error;}