/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* A security identifier table (sidtab) is a lookup table
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* of security context structures indexed by SID value.
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*
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* Original author: Stephen Smalley, <sds@tycho.nsa.gov>
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* Author: Ondrej Mosnacek, <omosnacek@gmail.com>
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*
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* Copyright (C) 2018 Red Hat, Inc.
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*/
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#ifndef _SS_SIDTAB_H_
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#define _SS_SIDTAB_H_
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#include <linux/spinlock_types.h>
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#include <linux/log2.h>
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#include <linux/hashtable.h>
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#include "context.h"
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struct sidtab_entry_leaf {
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u32 sid;
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struct context context;
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struct hlist_node list;
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};
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struct sidtab_node_inner;
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struct sidtab_node_leaf;
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union sidtab_entry_inner {
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struct sidtab_node_inner *ptr_inner;
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struct sidtab_node_leaf *ptr_leaf;
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};
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/* align node size to page boundary */
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#define SIDTAB_NODE_ALLOC_SHIFT PAGE_SHIFT
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#define SIDTAB_NODE_ALLOC_SIZE PAGE_SIZE
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#define size_to_shift(size) ((size) == 1 ? 1 : (const_ilog2((size) - 1) + 1))
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#define SIDTAB_INNER_SHIFT \
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(SIDTAB_NODE_ALLOC_SHIFT - size_to_shift(sizeof(union sidtab_entry_inner)))
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#define SIDTAB_INNER_ENTRIES ((size_t)1 << SIDTAB_INNER_SHIFT)
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#define SIDTAB_LEAF_ENTRIES \
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(SIDTAB_NODE_ALLOC_SIZE / sizeof(struct sidtab_entry_leaf))
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#define SIDTAB_MAX_BITS 32
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#define SIDTAB_MAX U32_MAX
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/* ensure enough tree levels for SIDTAB_MAX entries */
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#define SIDTAB_MAX_LEVEL \
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DIV_ROUND_UP(SIDTAB_MAX_BITS - size_to_shift(SIDTAB_LEAF_ENTRIES), \
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SIDTAB_INNER_SHIFT)
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struct sidtab_node_leaf {
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struct sidtab_entry_leaf entries[SIDTAB_LEAF_ENTRIES];
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};
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struct sidtab_node_inner {
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union sidtab_entry_inner entries[SIDTAB_INNER_ENTRIES];
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};
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struct sidtab_isid_entry {
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int set;
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struct sidtab_entry_leaf leaf;
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};
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struct sidtab_convert_params {
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int (*func)(struct context *oldc, struct context *newc, void *args);
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void *args;
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struct sidtab *target;
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};
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#define SIDTAB_HASH_BITS CONFIG_SECURITY_SELINUX_SIDTAB_HASH_BITS
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#define SIDTAB_HASH_BUCKETS (1 << SIDTAB_HASH_BITS)
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struct sidtab {
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/*
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* lock-free read access only for as many items as a prior read of
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* 'count'
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*/
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union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1];
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/*
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* access atomically via {READ|WRITE}_ONCE(); only increment under
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* spinlock
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*/
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u32 count;
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/* access only under spinlock */
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struct sidtab_convert_params *convert;
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spinlock_t lock;
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/* index == SID - 1 (no entry for SECSID_NULL) */
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struct sidtab_isid_entry isids[SECINITSID_NUM];
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/* Hash table for fast reverse context-to-sid lookups. */
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DECLARE_HASHTABLE(context_to_sid, SIDTAB_HASH_BITS);
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};
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int sidtab_init(struct sidtab *s);
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int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context);
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struct context *sidtab_search(struct sidtab *s, u32 sid);
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struct context *sidtab_search_force(struct sidtab *s, u32 sid);
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int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params);
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int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);
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void sidtab_destroy(struct sidtab *s);
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int sidtab_hash_stats(struct sidtab *sidtab, char *page);
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#endif /* _SS_SIDTAB_H_ */
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