782ebb992e
This patch improves memory use by SELinux by both reducing the avtab node
size and reducing the number of avtab nodes. The memory savings are
substantial, e.g. on a 64-bit system after boot, James Morris reported the
following data for the targeted and strict policies:
#objs objsize kernmem
Targeted:
Before: 237888 40 9.1MB
After: 19968 24 468KB
Strict:
Before: 571680 40 21.81MB
After: 221052 24 5.06MB
The improvement in memory use comes at a cost in the speed of security
server computations of access vectors, but these computations are only
required on AVC cache misses, and performance measurements by James Morris
using a number of benchmarks have shown that the change does not cause any
significant degradation.
Note that a rebuilt policy via an updated policy toolchain
(libsepol/checkpolicy) is required in order to gain the full benefits of
this patch, although some memory savings benefits are immediately applied
even to older policies (in particular, the reduction in avtab node size).
Sources for the updated toolchain are presently available from the
sourceforge CVS tree (http://sourceforge.net/cvs/?group_id=21266), and
tarballs are available from http://www.flux.utah.edu/~sds.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
84 lines
2.5 KiB
C
84 lines
2.5 KiB
C
/*
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* An access vector table (avtab) is a hash table
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* of access vectors and transition types indexed
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* by a type pair and a class. An access vector
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* table is used to represent the type enforcement
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* tables.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
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*
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* Added conditional policy language extensions
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*
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* Copyright (C) 2003 Tresys Technology, LLC
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2.
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*/
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#ifndef _SS_AVTAB_H_
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#define _SS_AVTAB_H_
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struct avtab_key {
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u16 source_type; /* source type */
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u16 target_type; /* target type */
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u16 target_class; /* target object class */
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#define AVTAB_ALLOWED 1
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#define AVTAB_AUDITALLOW 2
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#define AVTAB_AUDITDENY 4
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#define AVTAB_AV (AVTAB_ALLOWED | AVTAB_AUDITALLOW | AVTAB_AUDITDENY)
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#define AVTAB_TRANSITION 16
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#define AVTAB_MEMBER 32
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#define AVTAB_CHANGE 64
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#define AVTAB_TYPE (AVTAB_TRANSITION | AVTAB_MEMBER | AVTAB_CHANGE)
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#define AVTAB_ENABLED_OLD 0x80000000 /* reserved for used in cond_avtab */
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#define AVTAB_ENABLED 0x8000 /* reserved for used in cond_avtab */
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u16 specified; /* what field is specified */
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};
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struct avtab_datum {
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u32 data; /* access vector or type value */
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};
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struct avtab_node {
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struct avtab_key key;
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struct avtab_datum datum;
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struct avtab_node *next;
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};
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struct avtab {
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struct avtab_node **htable;
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u32 nel; /* number of elements */
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};
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int avtab_init(struct avtab *);
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struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k);
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void avtab_destroy(struct avtab *h);
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void avtab_hash_eval(struct avtab *h, char *tag);
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int avtab_read_item(void *fp, uint32_t vers, struct avtab *a,
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int (*insert)(struct avtab *a, struct avtab_key *k,
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struct avtab_datum *d, void *p),
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void *p);
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int avtab_read(struct avtab *a, void *fp, u32 vers);
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struct avtab_node *avtab_insert_nonunique(struct avtab *h, struct avtab_key *key,
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struct avtab_datum *datum);
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struct avtab_node *avtab_search_node(struct avtab *h, struct avtab_key *key);
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struct avtab_node *avtab_search_node_next(struct avtab_node *node, int specified);
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void avtab_cache_init(void);
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void avtab_cache_destroy(void);
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#define AVTAB_HASH_BITS 15
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#define AVTAB_HASH_BUCKETS (1 << AVTAB_HASH_BITS)
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#define AVTAB_HASH_MASK (AVTAB_HASH_BUCKETS-1)
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#define AVTAB_SIZE AVTAB_HASH_BUCKETS
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#endif /* _SS_AVTAB_H_ */
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