| 1 |
62 |
marcus.erl |
/*
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| 2 |
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* Implementation of the kernel access vector cache (AVC).
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| 3 |
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*
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| 4 |
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* Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
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| 5 |
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* James Morris <jmorris@redhat.com>
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| 6 |
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*
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| 7 |
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* Update: KaiGai, Kohei <kaigai@ak.jp.nec.com>
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| 8 |
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* Replaced the avc_lock spinlock by RCU.
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| 9 |
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*
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* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*
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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 version 2,
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* as published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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| 17 |
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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| 19 |
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#include <linux/slab.h>
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#include <linux/fs.h>
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| 21 |
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#include <linux/dcache.h>
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#include <linux/init.h>
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| 23 |
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#include <linux/skbuff.h>
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| 24 |
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#include <linux/percpu.h>
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#include <net/sock.h>
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#include <linux/un.h>
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#include <net/af_unix.h>
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#include <linux/ip.h>
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#include <linux/audit.h>
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#include "avc.h"
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| 33 |
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#include "avc_ss.h"
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| 35 |
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static const struct av_perm_to_string av_perm_to_string[] = {
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#define S_(c, v, s) { c, v, s },
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#include "av_perm_to_string.h"
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#undef S_
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| 39 |
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};
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| 40 |
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| 41 |
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static const char *class_to_string[] = {
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| 42 |
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#define S_(s) s,
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#include "class_to_string.h"
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| 44 |
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#undef S_
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| 45 |
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};
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| 47 |
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#define TB_(s) static const char * s [] = {
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| 48 |
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#define TE_(s) };
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| 49 |
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#define S_(s) s,
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#include "common_perm_to_string.h"
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#undef TB_
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#undef TE_
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#undef S_
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| 55 |
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static const struct av_inherit av_inherit[] = {
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#define S_(c, i, b) { c, common_##i##_perm_to_string, b },
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#include "av_inherit.h"
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#undef S_
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};
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| 61 |
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const struct selinux_class_perm selinux_class_perm = {
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av_perm_to_string,
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ARRAY_SIZE(av_perm_to_string),
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class_to_string,
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ARRAY_SIZE(class_to_string),
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av_inherit,
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ARRAY_SIZE(av_inherit)
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| 68 |
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};
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| 69 |
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| 70 |
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#define AVC_CACHE_SLOTS 512
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#define AVC_DEF_CACHE_THRESHOLD 512
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#define AVC_CACHE_RECLAIM 16
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| 74 |
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#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
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#define avc_cache_stats_incr(field) \
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do { \
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per_cpu(avc_cache_stats, get_cpu()).field++; \
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put_cpu(); \
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| 79 |
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} while (0)
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| 80 |
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#else
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| 81 |
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#define avc_cache_stats_incr(field) do {} while (0)
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| 82 |
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#endif
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| 83 |
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| 84 |
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struct avc_entry {
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| 85 |
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u32 ssid;
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| 86 |
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u32 tsid;
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| 87 |
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u16 tclass;
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| 88 |
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struct av_decision avd;
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| 89 |
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atomic_t used; /* used recently */
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| 90 |
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};
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| 92 |
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struct avc_node {
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struct avc_entry ae;
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| 94 |
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struct list_head list;
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| 95 |
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struct rcu_head rhead;
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| 96 |
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};
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| 98 |
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struct avc_cache {
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| 99 |
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struct list_head slots[AVC_CACHE_SLOTS];
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| 100 |
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spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
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| 101 |
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atomic_t lru_hint; /* LRU hint for reclaim scan */
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| 102 |
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atomic_t active_nodes;
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u32 latest_notif; /* latest revocation notification */
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| 104 |
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};
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| 106 |
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struct avc_callback_node {
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int (*callback) (u32 event, u32 ssid, u32 tsid,
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u16 tclass, u32 perms,
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u32 *out_retained);
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u32 events;
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| 111 |
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u32 ssid;
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| 112 |
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u32 tsid;
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u16 tclass;
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| 114 |
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u32 perms;
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| 115 |
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struct avc_callback_node *next;
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};
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| 118 |
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/* Exported via selinufs */
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unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
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| 121 |
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#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
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DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
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#endif
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| 125 |
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static struct avc_cache avc_cache;
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static struct avc_callback_node *avc_callbacks;
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static struct kmem_cache *avc_node_cachep;
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| 129 |
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static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
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{
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| 131 |
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return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
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}
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| 133 |
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| 134 |
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/**
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* avc_dump_av - Display an access vector in human-readable form.
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* @tclass: target security class
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* @av: access vector
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*/
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static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
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{
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| 141 |
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const char **common_pts = NULL;
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| 142 |
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u32 common_base = 0;
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| 143 |
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int i, i2, perm;
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| 145 |
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if (av == 0) {
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| 146 |
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audit_log_format(ab, " null");
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| 147 |
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return;
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| 148 |
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}
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| 149 |
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| 150 |
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for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
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| 151 |
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if (av_inherit[i].tclass == tclass) {
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common_pts = av_inherit[i].common_pts;
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| 153 |
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common_base = av_inherit[i].common_base;
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break;
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| 155 |
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}
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}
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| 157 |
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| 158 |
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audit_log_format(ab, " {");
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i = 0;
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perm = 1;
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while (perm < common_base) {
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| 162 |
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if (perm & av) {
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audit_log_format(ab, " %s", common_pts[i]);
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av &= ~perm;
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| 165 |
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}
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i++;
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perm <<= 1;
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}
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| 170 |
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while (i < sizeof(av) * 8) {
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| 171 |
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if (perm & av) {
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for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) {
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if ((av_perm_to_string[i2].tclass == tclass) &&
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(av_perm_to_string[i2].value == perm))
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break;
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}
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| 177 |
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if (i2 < ARRAY_SIZE(av_perm_to_string)) {
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| 178 |
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audit_log_format(ab, " %s",
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| 179 |
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av_perm_to_string[i2].name);
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| 180 |
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av &= ~perm;
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| 181 |
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}
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| 182 |
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}
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| 183 |
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i++;
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perm <<= 1;
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| 185 |
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}
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| 186 |
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| 187 |
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if (av)
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| 188 |
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audit_log_format(ab, " 0x%x", av);
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| 189 |
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| 190 |
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audit_log_format(ab, " }");
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| 191 |
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}
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| 192 |
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| 193 |
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/**
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| 194 |
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* avc_dump_query - Display a SID pair and a class in human-readable form.
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| 195 |
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* @ssid: source security identifier
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| 196 |
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* @tsid: target security identifier
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| 197 |
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* @tclass: target security class
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| 198 |
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*/
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| 199 |
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static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
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| 200 |
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{
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| 201 |
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int rc;
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| 202 |
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char *scontext;
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| 203 |
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u32 scontext_len;
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| 204 |
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| 205 |
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rc = security_sid_to_context(ssid, &scontext, &scontext_len);
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| 206 |
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if (rc)
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| 207 |
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audit_log_format(ab, "ssid=%d", ssid);
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| 208 |
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else {
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| 209 |
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audit_log_format(ab, "scontext=%s", scontext);
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| 210 |
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kfree(scontext);
|
| 211 |
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}
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| 212 |
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| 213 |
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rc = security_sid_to_context(tsid, &scontext, &scontext_len);
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| 214 |
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if (rc)
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| 215 |
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audit_log_format(ab, " tsid=%d", tsid);
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| 216 |
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else {
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| 217 |
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audit_log_format(ab, " tcontext=%s", scontext);
|
| 218 |
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kfree(scontext);
|
| 219 |
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}
|
| 220 |
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|
| 221 |
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BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]);
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| 222 |
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audit_log_format(ab, " tclass=%s", class_to_string[tclass]);
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| 223 |
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}
|
| 224 |
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|
| 225 |
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/**
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| 226 |
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* avc_init - Initialize the AVC.
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| 227 |
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*
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| 228 |
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* Initialize the access vector cache.
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| 229 |
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*/
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| 230 |
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void __init avc_init(void)
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| 231 |
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{
|
| 232 |
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int i;
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| 233 |
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| 234 |
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for (i = 0; i < AVC_CACHE_SLOTS; i++) {
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| 235 |
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INIT_LIST_HEAD(&avc_cache.slots[i]);
|
| 236 |
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spin_lock_init(&avc_cache.slots_lock[i]);
|
| 237 |
|
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}
|
| 238 |
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atomic_set(&avc_cache.active_nodes, 0);
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| 239 |
|
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atomic_set(&avc_cache.lru_hint, 0);
|
| 240 |
|
|
|
| 241 |
|
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avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
|
| 242 |
|
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0, SLAB_PANIC, NULL);
|
| 243 |
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|
|
| 244 |
|
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audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n");
|
| 245 |
|
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}
|
| 246 |
|
|
|
| 247 |
|
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int avc_get_hash_stats(char *page)
|
| 248 |
|
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{
|
| 249 |
|
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int i, chain_len, max_chain_len, slots_used;
|
| 250 |
|
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struct avc_node *node;
|
| 251 |
|
|
|
| 252 |
|
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rcu_read_lock();
|
| 253 |
|
|
|
| 254 |
|
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slots_used = 0;
|
| 255 |
|
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max_chain_len = 0;
|
| 256 |
|
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for (i = 0; i < AVC_CACHE_SLOTS; i++) {
|
| 257 |
|
|
if (!list_empty(&avc_cache.slots[i])) {
|
| 258 |
|
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slots_used++;
|
| 259 |
|
|
chain_len = 0;
|
| 260 |
|
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list_for_each_entry_rcu(node, &avc_cache.slots[i], list)
|
| 261 |
|
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chain_len++;
|
| 262 |
|
|
if (chain_len > max_chain_len)
|
| 263 |
|
|
max_chain_len = chain_len;
|
| 264 |
|
|
}
|
| 265 |
|
|
}
|
| 266 |
|
|
|
| 267 |
|
|
rcu_read_unlock();
|
| 268 |
|
|
|
| 269 |
|
|
return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
|
| 270 |
|
|
"longest chain: %d\n",
|
| 271 |
|
|
atomic_read(&avc_cache.active_nodes),
|
| 272 |
|
|
slots_used, AVC_CACHE_SLOTS, max_chain_len);
|
| 273 |
|
|
}
|
| 274 |
|
|
|
| 275 |
|
|
static void avc_node_free(struct rcu_head *rhead)
|
| 276 |
|
|
{
|
| 277 |
|
|
struct avc_node *node = container_of(rhead, struct avc_node, rhead);
|
| 278 |
|
|
kmem_cache_free(avc_node_cachep, node);
|
| 279 |
|
|
avc_cache_stats_incr(frees);
|
| 280 |
|
|
}
|
| 281 |
|
|
|
| 282 |
|
|
static void avc_node_delete(struct avc_node *node)
|
| 283 |
|
|
{
|
| 284 |
|
|
list_del_rcu(&node->list);
|
| 285 |
|
|
call_rcu(&node->rhead, avc_node_free);
|
| 286 |
|
|
atomic_dec(&avc_cache.active_nodes);
|
| 287 |
|
|
}
|
| 288 |
|
|
|
| 289 |
|
|
static void avc_node_kill(struct avc_node *node)
|
| 290 |
|
|
{
|
| 291 |
|
|
kmem_cache_free(avc_node_cachep, node);
|
| 292 |
|
|
avc_cache_stats_incr(frees);
|
| 293 |
|
|
atomic_dec(&avc_cache.active_nodes);
|
| 294 |
|
|
}
|
| 295 |
|
|
|
| 296 |
|
|
static void avc_node_replace(struct avc_node *new, struct avc_node *old)
|
| 297 |
|
|
{
|
| 298 |
|
|
list_replace_rcu(&old->list, &new->list);
|
| 299 |
|
|
call_rcu(&old->rhead, avc_node_free);
|
| 300 |
|
|
atomic_dec(&avc_cache.active_nodes);
|
| 301 |
|
|
}
|
| 302 |
|
|
|
| 303 |
|
|
static inline int avc_reclaim_node(void)
|
| 304 |
|
|
{
|
| 305 |
|
|
struct avc_node *node;
|
| 306 |
|
|
int hvalue, try, ecx;
|
| 307 |
|
|
unsigned long flags;
|
| 308 |
|
|
|
| 309 |
|
|
for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++ ) {
|
| 310 |
|
|
hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
|
| 311 |
|
|
|
| 312 |
|
|
if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
|
| 313 |
|
|
continue;
|
| 314 |
|
|
|
| 315 |
|
|
list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
|
| 316 |
|
|
if (atomic_dec_and_test(&node->ae.used)) {
|
| 317 |
|
|
/* Recently Unused */
|
| 318 |
|
|
avc_node_delete(node);
|
| 319 |
|
|
avc_cache_stats_incr(reclaims);
|
| 320 |
|
|
ecx++;
|
| 321 |
|
|
if (ecx >= AVC_CACHE_RECLAIM) {
|
| 322 |
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
|
| 323 |
|
|
goto out;
|
| 324 |
|
|
}
|
| 325 |
|
|
}
|
| 326 |
|
|
}
|
| 327 |
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
|
| 328 |
|
|
}
|
| 329 |
|
|
out:
|
| 330 |
|
|
return ecx;
|
| 331 |
|
|
}
|
| 332 |
|
|
|
| 333 |
|
|
static struct avc_node *avc_alloc_node(void)
|
| 334 |
|
|
{
|
| 335 |
|
|
struct avc_node *node;
|
| 336 |
|
|
|
| 337 |
|
|
node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
|
| 338 |
|
|
if (!node)
|
| 339 |
|
|
goto out;
|
| 340 |
|
|
|
| 341 |
|
|
INIT_RCU_HEAD(&node->rhead);
|
| 342 |
|
|
INIT_LIST_HEAD(&node->list);
|
| 343 |
|
|
atomic_set(&node->ae.used, 1);
|
| 344 |
|
|
avc_cache_stats_incr(allocations);
|
| 345 |
|
|
|
| 346 |
|
|
if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
|
| 347 |
|
|
avc_reclaim_node();
|
| 348 |
|
|
|
| 349 |
|
|
out:
|
| 350 |
|
|
return node;
|
| 351 |
|
|
}
|
| 352 |
|
|
|
| 353 |
|
|
static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
|
| 354 |
|
|
{
|
| 355 |
|
|
node->ae.ssid = ssid;
|
| 356 |
|
|
node->ae.tsid = tsid;
|
| 357 |
|
|
node->ae.tclass = tclass;
|
| 358 |
|
|
memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
|
| 359 |
|
|
}
|
| 360 |
|
|
|
| 361 |
|
|
static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
|
| 362 |
|
|
{
|
| 363 |
|
|
struct avc_node *node, *ret = NULL;
|
| 364 |
|
|
int hvalue;
|
| 365 |
|
|
|
| 366 |
|
|
hvalue = avc_hash(ssid, tsid, tclass);
|
| 367 |
|
|
list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
|
| 368 |
|
|
if (ssid == node->ae.ssid &&
|
| 369 |
|
|
tclass == node->ae.tclass &&
|
| 370 |
|
|
tsid == node->ae.tsid) {
|
| 371 |
|
|
ret = node;
|
| 372 |
|
|
break;
|
| 373 |
|
|
}
|
| 374 |
|
|
}
|
| 375 |
|
|
|
| 376 |
|
|
if (ret == NULL) {
|
| 377 |
|
|
/* cache miss */
|
| 378 |
|
|
goto out;
|
| 379 |
|
|
}
|
| 380 |
|
|
|
| 381 |
|
|
/* cache hit */
|
| 382 |
|
|
if (atomic_read(&ret->ae.used) != 1)
|
| 383 |
|
|
atomic_set(&ret->ae.used, 1);
|
| 384 |
|
|
out:
|
| 385 |
|
|
return ret;
|
| 386 |
|
|
}
|
| 387 |
|
|
|
| 388 |
|
|
/**
|
| 389 |
|
|
* avc_lookup - Look up an AVC entry.
|
| 390 |
|
|
* @ssid: source security identifier
|
| 391 |
|
|
* @tsid: target security identifier
|
| 392 |
|
|
* @tclass: target security class
|
| 393 |
|
|
* @requested: requested permissions, interpreted based on @tclass
|
| 394 |
|
|
*
|
| 395 |
|
|
* Look up an AVC entry that is valid for the
|
| 396 |
|
|
* @requested permissions between the SID pair
|
| 397 |
|
|
* (@ssid, @tsid), interpreting the permissions
|
| 398 |
|
|
* based on @tclass. If a valid AVC entry exists,
|
| 399 |
|
|
* then this function return the avc_node.
|
| 400 |
|
|
* Otherwise, this function returns NULL.
|
| 401 |
|
|
*/
|
| 402 |
|
|
static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
|
| 403 |
|
|
{
|
| 404 |
|
|
struct avc_node *node;
|
| 405 |
|
|
|
| 406 |
|
|
avc_cache_stats_incr(lookups);
|
| 407 |
|
|
node = avc_search_node(ssid, tsid, tclass);
|
| 408 |
|
|
|
| 409 |
|
|
if (node && ((node->ae.avd.decided & requested) == requested)) {
|
| 410 |
|
|
avc_cache_stats_incr(hits);
|
| 411 |
|
|
goto out;
|
| 412 |
|
|
}
|
| 413 |
|
|
|
| 414 |
|
|
node = NULL;
|
| 415 |
|
|
avc_cache_stats_incr(misses);
|
| 416 |
|
|
out:
|
| 417 |
|
|
return node;
|
| 418 |
|
|
}
|
| 419 |
|
|
|
| 420 |
|
|
static int avc_latest_notif_update(int seqno, int is_insert)
|
| 421 |
|
|
{
|
| 422 |
|
|
int ret = 0;
|
| 423 |
|
|
static DEFINE_SPINLOCK(notif_lock);
|
| 424 |
|
|
unsigned long flag;
|
| 425 |
|
|
|
| 426 |
|
|
spin_lock_irqsave(¬if_lock, flag);
|
| 427 |
|
|
if (is_insert) {
|
| 428 |
|
|
if (seqno < avc_cache.latest_notif) {
|
| 429 |
|
|
printk(KERN_WARNING "avc: seqno %d < latest_notif %d\n",
|
| 430 |
|
|
seqno, avc_cache.latest_notif);
|
| 431 |
|
|
ret = -EAGAIN;
|
| 432 |
|
|
}
|
| 433 |
|
|
} else {
|
| 434 |
|
|
if (seqno > avc_cache.latest_notif)
|
| 435 |
|
|
avc_cache.latest_notif = seqno;
|
| 436 |
|
|
}
|
| 437 |
|
|
spin_unlock_irqrestore(¬if_lock, flag);
|
| 438 |
|
|
|
| 439 |
|
|
return ret;
|
| 440 |
|
|
}
|
| 441 |
|
|
|
| 442 |
|
|
/**
|
| 443 |
|
|
* avc_insert - Insert an AVC entry.
|
| 444 |
|
|
* @ssid: source security identifier
|
| 445 |
|
|
* @tsid: target security identifier
|
| 446 |
|
|
* @tclass: target security class
|
| 447 |
|
|
* @ae: AVC entry
|
| 448 |
|
|
*
|
| 449 |
|
|
* Insert an AVC entry for the SID pair
|
| 450 |
|
|
* (@ssid, @tsid) and class @tclass.
|
| 451 |
|
|
* The access vectors and the sequence number are
|
| 452 |
|
|
* normally provided by the security server in
|
| 453 |
|
|
* response to a security_compute_av() call. If the
|
| 454 |
|
|
* sequence number @ae->avd.seqno is not less than the latest
|
| 455 |
|
|
* revocation notification, then the function copies
|
| 456 |
|
|
* the access vectors into a cache entry, returns
|
| 457 |
|
|
* avc_node inserted. Otherwise, this function returns NULL.
|
| 458 |
|
|
*/
|
| 459 |
|
|
static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
|
| 460 |
|
|
{
|
| 461 |
|
|
struct avc_node *pos, *node = NULL;
|
| 462 |
|
|
int hvalue;
|
| 463 |
|
|
unsigned long flag;
|
| 464 |
|
|
|
| 465 |
|
|
if (avc_latest_notif_update(ae->avd.seqno, 1))
|
| 466 |
|
|
goto out;
|
| 467 |
|
|
|
| 468 |
|
|
node = avc_alloc_node();
|
| 469 |
|
|
if (node) {
|
| 470 |
|
|
hvalue = avc_hash(ssid, tsid, tclass);
|
| 471 |
|
|
avc_node_populate(node, ssid, tsid, tclass, ae);
|
| 472 |
|
|
|
| 473 |
|
|
spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
|
| 474 |
|
|
list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
|
| 475 |
|
|
if (pos->ae.ssid == ssid &&
|
| 476 |
|
|
pos->ae.tsid == tsid &&
|
| 477 |
|
|
pos->ae.tclass == tclass) {
|
| 478 |
|
|
avc_node_replace(node, pos);
|
| 479 |
|
|
goto found;
|
| 480 |
|
|
}
|
| 481 |
|
|
}
|
| 482 |
|
|
list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
|
| 483 |
|
|
found:
|
| 484 |
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
|
| 485 |
|
|
}
|
| 486 |
|
|
out:
|
| 487 |
|
|
return node;
|
| 488 |
|
|
}
|
| 489 |
|
|
|
| 490 |
|
|
static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
|
| 491 |
|
|
struct in6_addr *addr, __be16 port,
|
| 492 |
|
|
char *name1, char *name2)
|
| 493 |
|
|
{
|
| 494 |
|
|
if (!ipv6_addr_any(addr))
|
| 495 |
|
|
audit_log_format(ab, " %s=" NIP6_FMT, name1, NIP6(*addr));
|
| 496 |
|
|
if (port)
|
| 497 |
|
|
audit_log_format(ab, " %s=%d", name2, ntohs(port));
|
| 498 |
|
|
}
|
| 499 |
|
|
|
| 500 |
|
|
static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
|
| 501 |
|
|
__be16 port, char *name1, char *name2)
|
| 502 |
|
|
{
|
| 503 |
|
|
if (addr)
|
| 504 |
|
|
audit_log_format(ab, " %s=" NIPQUAD_FMT, name1, NIPQUAD(addr));
|
| 505 |
|
|
if (port)
|
| 506 |
|
|
audit_log_format(ab, " %s=%d", name2, ntohs(port));
|
| 507 |
|
|
}
|
| 508 |
|
|
|
| 509 |
|
|
/**
|
| 510 |
|
|
* avc_audit - Audit the granting or denial of permissions.
|
| 511 |
|
|
* @ssid: source security identifier
|
| 512 |
|
|
* @tsid: target security identifier
|
| 513 |
|
|
* @tclass: target security class
|
| 514 |
|
|
* @requested: requested permissions
|
| 515 |
|
|
* @avd: access vector decisions
|
| 516 |
|
|
* @result: result from avc_has_perm_noaudit
|
| 517 |
|
|
* @a: auxiliary audit data
|
| 518 |
|
|
*
|
| 519 |
|
|
* Audit the granting or denial of permissions in accordance
|
| 520 |
|
|
* with the policy. This function is typically called by
|
| 521 |
|
|
* avc_has_perm() after a permission check, but can also be
|
| 522 |
|
|
* called directly by callers who use avc_has_perm_noaudit()
|
| 523 |
|
|
* in order to separate the permission check from the auditing.
|
| 524 |
|
|
* For example, this separation is useful when the permission check must
|
| 525 |
|
|
* be performed under a lock, to allow the lock to be released
|
| 526 |
|
|
* before calling the auditing code.
|
| 527 |
|
|
*/
|
| 528 |
|
|
void avc_audit(u32 ssid, u32 tsid,
|
| 529 |
|
|
u16 tclass, u32 requested,
|
| 530 |
|
|
struct av_decision *avd, int result, struct avc_audit_data *a)
|
| 531 |
|
|
{
|
| 532 |
|
|
struct task_struct *tsk = current;
|
| 533 |
|
|
struct inode *inode = NULL;
|
| 534 |
|
|
u32 denied, audited;
|
| 535 |
|
|
struct audit_buffer *ab;
|
| 536 |
|
|
|
| 537 |
|
|
denied = requested & ~avd->allowed;
|
| 538 |
|
|
if (denied) {
|
| 539 |
|
|
audited = denied;
|
| 540 |
|
|
if (!(audited & avd->auditdeny))
|
| 541 |
|
|
return;
|
| 542 |
|
|
} else if (result) {
|
| 543 |
|
|
audited = denied = requested;
|
| 544 |
|
|
} else {
|
| 545 |
|
|
audited = requested;
|
| 546 |
|
|
if (!(audited & avd->auditallow))
|
| 547 |
|
|
return;
|
| 548 |
|
|
}
|
| 549 |
|
|
|
| 550 |
|
|
ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
|
| 551 |
|
|
if (!ab)
|
| 552 |
|
|
return; /* audit_panic has been called */
|
| 553 |
|
|
audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted");
|
| 554 |
|
|
avc_dump_av(ab, tclass,audited);
|
| 555 |
|
|
audit_log_format(ab, " for ");
|
| 556 |
|
|
if (a && a->tsk)
|
| 557 |
|
|
tsk = a->tsk;
|
| 558 |
|
|
if (tsk && tsk->pid) {
|
| 559 |
|
|
audit_log_format(ab, " pid=%d comm=", tsk->pid);
|
| 560 |
|
|
audit_log_untrustedstring(ab, tsk->comm);
|
| 561 |
|
|
}
|
| 562 |
|
|
if (a) {
|
| 563 |
|
|
switch (a->type) {
|
| 564 |
|
|
case AVC_AUDIT_DATA_IPC:
|
| 565 |
|
|
audit_log_format(ab, " key=%d", a->u.ipc_id);
|
| 566 |
|
|
break;
|
| 567 |
|
|
case AVC_AUDIT_DATA_CAP:
|
| 568 |
|
|
audit_log_format(ab, " capability=%d", a->u.cap);
|
| 569 |
|
|
break;
|
| 570 |
|
|
case AVC_AUDIT_DATA_FS:
|
| 571 |
|
|
if (a->u.fs.dentry) {
|
| 572 |
|
|
struct dentry *dentry = a->u.fs.dentry;
|
| 573 |
|
|
if (a->u.fs.mnt) {
|
| 574 |
|
|
audit_log_d_path(ab, "path=", dentry, a->u.fs.mnt);
|
| 575 |
|
|
} else {
|
| 576 |
|
|
audit_log_format(ab, " name=");
|
| 577 |
|
|
audit_log_untrustedstring(ab, dentry->d_name.name);
|
| 578 |
|
|
}
|
| 579 |
|
|
inode = dentry->d_inode;
|
| 580 |
|
|
} else if (a->u.fs.inode) {
|
| 581 |
|
|
struct dentry *dentry;
|
| 582 |
|
|
inode = a->u.fs.inode;
|
| 583 |
|
|
dentry = d_find_alias(inode);
|
| 584 |
|
|
if (dentry) {
|
| 585 |
|
|
audit_log_format(ab, " name=");
|
| 586 |
|
|
audit_log_untrustedstring(ab, dentry->d_name.name);
|
| 587 |
|
|
dput(dentry);
|
| 588 |
|
|
}
|
| 589 |
|
|
}
|
| 590 |
|
|
if (inode)
|
| 591 |
|
|
audit_log_format(ab, " dev=%s ino=%lu",
|
| 592 |
|
|
inode->i_sb->s_id,
|
| 593 |
|
|
inode->i_ino);
|
| 594 |
|
|
break;
|
| 595 |
|
|
case AVC_AUDIT_DATA_NET:
|
| 596 |
|
|
if (a->u.net.sk) {
|
| 597 |
|
|
struct sock *sk = a->u.net.sk;
|
| 598 |
|
|
struct unix_sock *u;
|
| 599 |
|
|
int len = 0;
|
| 600 |
|
|
char *p = NULL;
|
| 601 |
|
|
|
| 602 |
|
|
switch (sk->sk_family) {
|
| 603 |
|
|
case AF_INET: {
|
| 604 |
|
|
struct inet_sock *inet = inet_sk(sk);
|
| 605 |
|
|
|
| 606 |
|
|
avc_print_ipv4_addr(ab, inet->rcv_saddr,
|
| 607 |
|
|
inet->sport,
|
| 608 |
|
|
"laddr", "lport");
|
| 609 |
|
|
avc_print_ipv4_addr(ab, inet->daddr,
|
| 610 |
|
|
inet->dport,
|
| 611 |
|
|
"faddr", "fport");
|
| 612 |
|
|
break;
|
| 613 |
|
|
}
|
| 614 |
|
|
case AF_INET6: {
|
| 615 |
|
|
struct inet_sock *inet = inet_sk(sk);
|
| 616 |
|
|
struct ipv6_pinfo *inet6 = inet6_sk(sk);
|
| 617 |
|
|
|
| 618 |
|
|
avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
|
| 619 |
|
|
inet->sport,
|
| 620 |
|
|
"laddr", "lport");
|
| 621 |
|
|
avc_print_ipv6_addr(ab, &inet6->daddr,
|
| 622 |
|
|
inet->dport,
|
| 623 |
|
|
"faddr", "fport");
|
| 624 |
|
|
break;
|
| 625 |
|
|
}
|
| 626 |
|
|
case AF_UNIX:
|
| 627 |
|
|
u = unix_sk(sk);
|
| 628 |
|
|
if (u->dentry) {
|
| 629 |
|
|
audit_log_d_path(ab, "path=",
|
| 630 |
|
|
u->dentry, u->mnt);
|
| 631 |
|
|
break;
|
| 632 |
|
|
}
|
| 633 |
|
|
if (!u->addr)
|
| 634 |
|
|
break;
|
| 635 |
|
|
len = u->addr->len-sizeof(short);
|
| 636 |
|
|
p = &u->addr->name->sun_path[0];
|
| 637 |
|
|
audit_log_format(ab, " path=");
|
| 638 |
|
|
if (*p)
|
| 639 |
|
|
audit_log_untrustedstring(ab, p);
|
| 640 |
|
|
else
|
| 641 |
|
|
audit_log_hex(ab, p, len);
|
| 642 |
|
|
break;
|
| 643 |
|
|
}
|
| 644 |
|
|
}
|
| 645 |
|
|
|
| 646 |
|
|
switch (a->u.net.family) {
|
| 647 |
|
|
case AF_INET:
|
| 648 |
|
|
avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
|
| 649 |
|
|
a->u.net.sport,
|
| 650 |
|
|
"saddr", "src");
|
| 651 |
|
|
avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
|
| 652 |
|
|
a->u.net.dport,
|
| 653 |
|
|
"daddr", "dest");
|
| 654 |
|
|
break;
|
| 655 |
|
|
case AF_INET6:
|
| 656 |
|
|
avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
|
| 657 |
|
|
a->u.net.sport,
|
| 658 |
|
|
"saddr", "src");
|
| 659 |
|
|
avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
|
| 660 |
|
|
a->u.net.dport,
|
| 661 |
|
|
"daddr", "dest");
|
| 662 |
|
|
break;
|
| 663 |
|
|
}
|
| 664 |
|
|
if (a->u.net.netif)
|
| 665 |
|
|
audit_log_format(ab, " netif=%s",
|
| 666 |
|
|
a->u.net.netif);
|
| 667 |
|
|
break;
|
| 668 |
|
|
}
|
| 669 |
|
|
}
|
| 670 |
|
|
audit_log_format(ab, " ");
|
| 671 |
|
|
avc_dump_query(ab, ssid, tsid, tclass);
|
| 672 |
|
|
audit_log_end(ab);
|
| 673 |
|
|
}
|
| 674 |
|
|
|
| 675 |
|
|
/**
|
| 676 |
|
|
* avc_add_callback - Register a callback for security events.
|
| 677 |
|
|
* @callback: callback function
|
| 678 |
|
|
* @events: security events
|
| 679 |
|
|
* @ssid: source security identifier or %SECSID_WILD
|
| 680 |
|
|
* @tsid: target security identifier or %SECSID_WILD
|
| 681 |
|
|
* @tclass: target security class
|
| 682 |
|
|
* @perms: permissions
|
| 683 |
|
|
*
|
| 684 |
|
|
* Register a callback function for events in the set @events
|
| 685 |
|
|
* related to the SID pair (@ssid, @tsid) and
|
| 686 |
|
|
* and the permissions @perms, interpreting
|
| 687 |
|
|
* @perms based on @tclass. Returns %0 on success or
|
| 688 |
|
|
* -%ENOMEM if insufficient memory exists to add the callback.
|
| 689 |
|
|
*/
|
| 690 |
|
|
int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
|
| 691 |
|
|
u16 tclass, u32 perms,
|
| 692 |
|
|
u32 *out_retained),
|
| 693 |
|
|
u32 events, u32 ssid, u32 tsid,
|
| 694 |
|
|
u16 tclass, u32 perms)
|
| 695 |
|
|
{
|
| 696 |
|
|
struct avc_callback_node *c;
|
| 697 |
|
|
int rc = 0;
|
| 698 |
|
|
|
| 699 |
|
|
c = kmalloc(sizeof(*c), GFP_ATOMIC);
|
| 700 |
|
|
if (!c) {
|
| 701 |
|
|
rc = -ENOMEM;
|
| 702 |
|
|
goto out;
|
| 703 |
|
|
}
|
| 704 |
|
|
|
| 705 |
|
|
c->callback = callback;
|
| 706 |
|
|
c->events = events;
|
| 707 |
|
|
c->ssid = ssid;
|
| 708 |
|
|
c->tsid = tsid;
|
| 709 |
|
|
c->perms = perms;
|
| 710 |
|
|
c->next = avc_callbacks;
|
| 711 |
|
|
avc_callbacks = c;
|
| 712 |
|
|
out:
|
| 713 |
|
|
return rc;
|
| 714 |
|
|
}
|
| 715 |
|
|
|
| 716 |
|
|
static inline int avc_sidcmp(u32 x, u32 y)
|
| 717 |
|
|
{
|
| 718 |
|
|
return (x == y || x == SECSID_WILD || y == SECSID_WILD);
|
| 719 |
|
|
}
|
| 720 |
|
|
|
| 721 |
|
|
/**
|
| 722 |
|
|
* avc_update_node Update an AVC entry
|
| 723 |
|
|
* @event : Updating event
|
| 724 |
|
|
* @perms : Permission mask bits
|
| 725 |
|
|
* @ssid,@tsid,@tclass : identifier of an AVC entry
|
| 726 |
|
|
*
|
| 727 |
|
|
* if a valid AVC entry doesn't exist,this function returns -ENOENT.
|
| 728 |
|
|
* if kmalloc() called internal returns NULL, this function returns -ENOMEM.
|
| 729 |
|
|
* otherwise, this function update the AVC entry. The original AVC-entry object
|
| 730 |
|
|
* will release later by RCU.
|
| 731 |
|
|
*/
|
| 732 |
|
|
static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
|
| 733 |
|
|
{
|
| 734 |
|
|
int hvalue, rc = 0;
|
| 735 |
|
|
unsigned long flag;
|
| 736 |
|
|
struct avc_node *pos, *node, *orig = NULL;
|
| 737 |
|
|
|
| 738 |
|
|
node = avc_alloc_node();
|
| 739 |
|
|
if (!node) {
|
| 740 |
|
|
rc = -ENOMEM;
|
| 741 |
|
|
goto out;
|
| 742 |
|
|
}
|
| 743 |
|
|
|
| 744 |
|
|
/* Lock the target slot */
|
| 745 |
|
|
hvalue = avc_hash(ssid, tsid, tclass);
|
| 746 |
|
|
spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
|
| 747 |
|
|
|
| 748 |
|
|
list_for_each_entry(pos, &avc_cache.slots[hvalue], list){
|
| 749 |
|
|
if ( ssid==pos->ae.ssid &&
|
| 750 |
|
|
tsid==pos->ae.tsid &&
|
| 751 |
|
|
tclass==pos->ae.tclass ){
|
| 752 |
|
|
orig = pos;
|
| 753 |
|
|
break;
|
| 754 |
|
|
}
|
| 755 |
|
|
}
|
| 756 |
|
|
|
| 757 |
|
|
if (!orig) {
|
| 758 |
|
|
rc = -ENOENT;
|
| 759 |
|
|
avc_node_kill(node);
|
| 760 |
|
|
goto out_unlock;
|
| 761 |
|
|
}
|
| 762 |
|
|
|
| 763 |
|
|
/*
|
| 764 |
|
|
* Copy and replace original node.
|
| 765 |
|
|
*/
|
| 766 |
|
|
|
| 767 |
|
|
avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
|
| 768 |
|
|
|
| 769 |
|
|
switch (event) {
|
| 770 |
|
|
case AVC_CALLBACK_GRANT:
|
| 771 |
|
|
node->ae.avd.allowed |= perms;
|
| 772 |
|
|
break;
|
| 773 |
|
|
case AVC_CALLBACK_TRY_REVOKE:
|
| 774 |
|
|
case AVC_CALLBACK_REVOKE:
|
| 775 |
|
|
node->ae.avd.allowed &= ~perms;
|
| 776 |
|
|
break;
|
| 777 |
|
|
case AVC_CALLBACK_AUDITALLOW_ENABLE:
|
| 778 |
|
|
node->ae.avd.auditallow |= perms;
|
| 779 |
|
|
break;
|
| 780 |
|
|
case AVC_CALLBACK_AUDITALLOW_DISABLE:
|
| 781 |
|
|
node->ae.avd.auditallow &= ~perms;
|
| 782 |
|
|
break;
|
| 783 |
|
|
case AVC_CALLBACK_AUDITDENY_ENABLE:
|
| 784 |
|
|
node->ae.avd.auditdeny |= perms;
|
| 785 |
|
|
break;
|
| 786 |
|
|
case AVC_CALLBACK_AUDITDENY_DISABLE:
|
| 787 |
|
|
node->ae.avd.auditdeny &= ~perms;
|
| 788 |
|
|
break;
|
| 789 |
|
|
}
|
| 790 |
|
|
avc_node_replace(node, orig);
|
| 791 |
|
|
out_unlock:
|
| 792 |
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
|
| 793 |
|
|
out:
|
| 794 |
|
|
return rc;
|
| 795 |
|
|
}
|
| 796 |
|
|
|
| 797 |
|
|
/**
|
| 798 |
|
|
* avc_ss_reset - Flush the cache and revalidate migrated permissions.
|
| 799 |
|
|
* @seqno: policy sequence number
|
| 800 |
|
|
*/
|
| 801 |
|
|
int avc_ss_reset(u32 seqno)
|
| 802 |
|
|
{
|
| 803 |
|
|
struct avc_callback_node *c;
|
| 804 |
|
|
int i, rc = 0, tmprc;
|
| 805 |
|
|
unsigned long flag;
|
| 806 |
|
|
struct avc_node *node;
|
| 807 |
|
|
|
| 808 |
|
|
for (i = 0; i < AVC_CACHE_SLOTS; i++) {
|
| 809 |
|
|
spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
|
| 810 |
|
|
list_for_each_entry(node, &avc_cache.slots[i], list)
|
| 811 |
|
|
avc_node_delete(node);
|
| 812 |
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
|
| 813 |
|
|
}
|
| 814 |
|
|
|
| 815 |
|
|
for (c = avc_callbacks; c; c = c->next) {
|
| 816 |
|
|
if (c->events & AVC_CALLBACK_RESET) {
|
| 817 |
|
|
tmprc = c->callback(AVC_CALLBACK_RESET,
|
| 818 |
|
|
0, 0, 0, 0, NULL);
|
| 819 |
|
|
/* save the first error encountered for the return
|
| 820 |
|
|
value and continue processing the callbacks */
|
| 821 |
|
|
if (!rc)
|
| 822 |
|
|
rc = tmprc;
|
| 823 |
|
|
}
|
| 824 |
|
|
}
|
| 825 |
|
|
|
| 826 |
|
|
avc_latest_notif_update(seqno, 0);
|
| 827 |
|
|
return rc;
|
| 828 |
|
|
}
|
| 829 |
|
|
|
| 830 |
|
|
/**
|
| 831 |
|
|
* avc_has_perm_noaudit - Check permissions but perform no auditing.
|
| 832 |
|
|
* @ssid: source security identifier
|
| 833 |
|
|
* @tsid: target security identifier
|
| 834 |
|
|
* @tclass: target security class
|
| 835 |
|
|
* @requested: requested permissions, interpreted based on @tclass
|
| 836 |
|
|
* @flags: AVC_STRICT or 0
|
| 837 |
|
|
* @avd: access vector decisions
|
| 838 |
|
|
*
|
| 839 |
|
|
* Check the AVC to determine whether the @requested permissions are granted
|
| 840 |
|
|
* for the SID pair (@ssid, @tsid), interpreting the permissions
|
| 841 |
|
|
* based on @tclass, and call the security server on a cache miss to obtain
|
| 842 |
|
|
* a new decision and add it to the cache. Return a copy of the decisions
|
| 843 |
|
|
* in @avd. Return %0 if all @requested permissions are granted,
|
| 844 |
|
|
* -%EACCES if any permissions are denied, or another -errno upon
|
| 845 |
|
|
* other errors. This function is typically called by avc_has_perm(),
|
| 846 |
|
|
* but may also be called directly to separate permission checking from
|
| 847 |
|
|
* auditing, e.g. in cases where a lock must be held for the check but
|
| 848 |
|
|
* should be released for the auditing.
|
| 849 |
|
|
*/
|
| 850 |
|
|
int avc_has_perm_noaudit(u32 ssid, u32 tsid,
|
| 851 |
|
|
u16 tclass, u32 requested,
|
| 852 |
|
|
unsigned flags,
|
| 853 |
|
|
struct av_decision *avd)
|
| 854 |
|
|
{
|
| 855 |
|
|
struct avc_node *node;
|
| 856 |
|
|
struct avc_entry entry, *p_ae;
|
| 857 |
|
|
int rc = 0;
|
| 858 |
|
|
u32 denied;
|
| 859 |
|
|
|
| 860 |
|
|
rcu_read_lock();
|
| 861 |
|
|
|
| 862 |
|
|
node = avc_lookup(ssid, tsid, tclass, requested);
|
| 863 |
|
|
if (!node) {
|
| 864 |
|
|
rcu_read_unlock();
|
| 865 |
|
|
rc = security_compute_av(ssid,tsid,tclass,requested,&entry.avd);
|
| 866 |
|
|
if (rc)
|
| 867 |
|
|
goto out;
|
| 868 |
|
|
rcu_read_lock();
|
| 869 |
|
|
node = avc_insert(ssid,tsid,tclass,&entry);
|
| 870 |
|
|
}
|
| 871 |
|
|
|
| 872 |
|
|
p_ae = node ? &node->ae : &entry;
|
| 873 |
|
|
|
| 874 |
|
|
if (avd)
|
| 875 |
|
|
memcpy(avd, &p_ae->avd, sizeof(*avd));
|
| 876 |
|
|
|
| 877 |
|
|
denied = requested & ~(p_ae->avd.allowed);
|
| 878 |
|
|
|
| 879 |
|
|
if (!requested || denied) {
|
| 880 |
|
|
if (selinux_enforcing || (flags & AVC_STRICT))
|
| 881 |
|
|
rc = -EACCES;
|
| 882 |
|
|
else
|
| 883 |
|
|
if (node)
|
| 884 |
|
|
avc_update_node(AVC_CALLBACK_GRANT,requested,
|
| 885 |
|
|
ssid,tsid,tclass);
|
| 886 |
|
|
}
|
| 887 |
|
|
|
| 888 |
|
|
rcu_read_unlock();
|
| 889 |
|
|
out:
|
| 890 |
|
|
return rc;
|
| 891 |
|
|
}
|
| 892 |
|
|
|
| 893 |
|
|
/**
|
| 894 |
|
|
* avc_has_perm - Check permissions and perform any appropriate auditing.
|
| 895 |
|
|
* @ssid: source security identifier
|
| 896 |
|
|
* @tsid: target security identifier
|
| 897 |
|
|
* @tclass: target security class
|
| 898 |
|
|
* @requested: requested permissions, interpreted based on @tclass
|
| 899 |
|
|
* @auditdata: auxiliary audit data
|
| 900 |
|
|
*
|
| 901 |
|
|
* Check the AVC to determine whether the @requested permissions are granted
|
| 902 |
|
|
* for the SID pair (@ssid, @tsid), interpreting the permissions
|
| 903 |
|
|
* based on @tclass, and call the security server on a cache miss to obtain
|
| 904 |
|
|
* a new decision and add it to the cache. Audit the granting or denial of
|
| 905 |
|
|
* permissions in accordance with the policy. Return %0 if all @requested
|
| 906 |
|
|
* permissions are granted, -%EACCES if any permissions are denied, or
|
| 907 |
|
|
* another -errno upon other errors.
|
| 908 |
|
|
*/
|
| 909 |
|
|
int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
|
| 910 |
|
|
u32 requested, struct avc_audit_data *auditdata)
|
| 911 |
|
|
{
|
| 912 |
|
|
struct av_decision avd;
|
| 913 |
|
|
int rc;
|
| 914 |
|
|
|
| 915 |
|
|
rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
|
| 916 |
|
|
avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
|
| 917 |
|
|
return rc;
|
| 918 |
|
|
}
|
| 919 |
|
|
|
| 920 |
|
|
u32 avc_policy_seqno(void)
|
| 921 |
|
|
{
|
| 922 |
|
|
return avc_cache.latest_notif;
|
| 923 |
|
|
}
|
