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![Stephen Smalley](/assets/img/avatar_default.png)
Per Steve Grubb's observation that there are some remaining cases where avc_audit() directly logs untrusted strings without escaping them, here is a patch that changes avc_audit() to use audit_log_untrustedstring() or audit_log_hex() as appropriate. Note that d_name.name is nul- terminated by d_alloc(), and that sun_path is nul-terminated by unix_mkname(), so it is not necessary for the AVC to create nul- terminated copies or to alter audit_log_untrustedstring to take a length argument. In the case of an abstract name, we use audit_log_hex() with an explicit length. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
917 lines
23 KiB
C
917 lines
23 KiB
C
/*
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* Implementation of the kernel access vector cache (AVC).
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*
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* Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
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* James Morris <jmorris@redhat.com>
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*
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* Update: KaiGai, Kohei <kaigai@ak.jp.nec.com>
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* Replaced the avc_lock spinlock by RCU.
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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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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/dcache.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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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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#include "avc_ss.h"
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static const struct av_perm_to_string
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{
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u16 tclass;
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u32 value;
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const char *name;
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} 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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};
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#ifdef CONFIG_AUDIT
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static const char *class_to_string[] = {
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#define S_(s) s,
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#include "class_to_string.h"
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#undef S_
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};
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#endif
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#define TB_(s) static const char * s [] = {
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#define TE_(s) };
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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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static const struct av_inherit
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{
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u16 tclass;
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const char **common_pts;
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u32 common_base;
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} 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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#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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#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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} while (0)
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#else
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#define avc_cache_stats_incr(field) do {} while (0)
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#endif
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struct avc_entry {
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u32 ssid;
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u32 tsid;
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u16 tclass;
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struct av_decision avd;
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atomic_t used; /* used recently */
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};
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struct avc_node {
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struct avc_entry ae;
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struct list_head list;
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struct rcu_head rhead;
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};
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struct avc_cache {
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struct list_head slots[AVC_CACHE_SLOTS];
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spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
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atomic_t lru_hint; /* LRU hint for reclaim scan */
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atomic_t active_nodes;
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u32 latest_notif; /* latest revocation notification */
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};
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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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u32 ssid;
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u32 tsid;
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u16 tclass;
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u32 perms;
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struct avc_callback_node *next;
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};
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/* Exported via selinufs */
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unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
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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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static struct avc_cache avc_cache;
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static struct avc_callback_node *avc_callbacks;
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static kmem_cache_t *avc_node_cachep;
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static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
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{
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return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
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}
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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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const char **common_pts = NULL;
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u32 common_base = 0;
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int i, i2, perm;
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if (av == 0) {
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audit_log_format(ab, " null");
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return;
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}
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for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
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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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common_base = av_inherit[i].common_base;
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break;
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}
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}
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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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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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}
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i++;
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perm <<= 1;
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}
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while (i < sizeof(av) * 8) {
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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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if (i2 < ARRAY_SIZE(av_perm_to_string)) {
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audit_log_format(ab, " %s",
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av_perm_to_string[i2].name);
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av &= ~perm;
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}
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}
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i++;
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perm <<= 1;
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}
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if (av)
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audit_log_format(ab, " 0x%x", av);
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audit_log_format(ab, " }");
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}
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/**
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* avc_dump_query - Display a SID pair and a class in human-readable form.
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* @ssid: source security identifier
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* @tsid: target security identifier
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* @tclass: target security class
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*/
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static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
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{
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int rc;
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char *scontext;
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u32 scontext_len;
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rc = security_sid_to_context(ssid, &scontext, &scontext_len);
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if (rc)
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audit_log_format(ab, "ssid=%d", ssid);
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else {
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audit_log_format(ab, "scontext=%s", scontext);
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kfree(scontext);
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}
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rc = security_sid_to_context(tsid, &scontext, &scontext_len);
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if (rc)
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audit_log_format(ab, " tsid=%d", tsid);
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else {
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audit_log_format(ab, " tcontext=%s", scontext);
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kfree(scontext);
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}
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audit_log_format(ab, " tclass=%s", class_to_string[tclass]);
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}
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/**
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* avc_init - Initialize the AVC.
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*
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* Initialize the access vector cache.
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*/
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void __init avc_init(void)
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{
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int i;
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for (i = 0; i < AVC_CACHE_SLOTS; i++) {
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INIT_LIST_HEAD(&avc_cache.slots[i]);
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spin_lock_init(&avc_cache.slots_lock[i]);
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}
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atomic_set(&avc_cache.active_nodes, 0);
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atomic_set(&avc_cache.lru_hint, 0);
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avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
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0, SLAB_PANIC, NULL, NULL);
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audit_log(current->audit_context, AUDIT_KERNEL, "AVC INITIALIZED\n");
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}
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int avc_get_hash_stats(char *page)
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{
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int i, chain_len, max_chain_len, slots_used;
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struct avc_node *node;
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rcu_read_lock();
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slots_used = 0;
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max_chain_len = 0;
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for (i = 0; i < AVC_CACHE_SLOTS; i++) {
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if (!list_empty(&avc_cache.slots[i])) {
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slots_used++;
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chain_len = 0;
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list_for_each_entry_rcu(node, &avc_cache.slots[i], list)
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chain_len++;
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if (chain_len > max_chain_len)
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max_chain_len = chain_len;
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}
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}
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rcu_read_unlock();
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return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
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"longest chain: %d\n",
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atomic_read(&avc_cache.active_nodes),
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slots_used, AVC_CACHE_SLOTS, max_chain_len);
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}
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static void avc_node_free(struct rcu_head *rhead)
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{
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struct avc_node *node = container_of(rhead, struct avc_node, rhead);
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kmem_cache_free(avc_node_cachep, node);
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avc_cache_stats_incr(frees);
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}
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static void avc_node_delete(struct avc_node *node)
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{
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list_del_rcu(&node->list);
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call_rcu(&node->rhead, avc_node_free);
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atomic_dec(&avc_cache.active_nodes);
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}
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static void avc_node_kill(struct avc_node *node)
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{
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kmem_cache_free(avc_node_cachep, node);
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avc_cache_stats_incr(frees);
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atomic_dec(&avc_cache.active_nodes);
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}
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static void avc_node_replace(struct avc_node *new, struct avc_node *old)
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{
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list_replace_rcu(&old->list, &new->list);
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call_rcu(&old->rhead, avc_node_free);
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atomic_dec(&avc_cache.active_nodes);
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}
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static inline int avc_reclaim_node(void)
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{
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struct avc_node *node;
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int hvalue, try, ecx;
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unsigned long flags;
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for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++ ) {
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hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
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if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
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continue;
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list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
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if (atomic_dec_and_test(&node->ae.used)) {
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/* Recently Unused */
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avc_node_delete(node);
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avc_cache_stats_incr(reclaims);
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ecx++;
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if (ecx >= AVC_CACHE_RECLAIM) {
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spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
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goto out;
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}
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}
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}
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spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
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}
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out:
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return ecx;
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}
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static struct avc_node *avc_alloc_node(void)
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{
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struct avc_node *node;
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node = kmem_cache_alloc(avc_node_cachep, SLAB_ATOMIC);
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if (!node)
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goto out;
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memset(node, 0, sizeof(*node));
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INIT_RCU_HEAD(&node->rhead);
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INIT_LIST_HEAD(&node->list);
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atomic_set(&node->ae.used, 1);
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avc_cache_stats_incr(allocations);
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if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
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avc_reclaim_node();
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out:
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return node;
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}
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static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
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{
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node->ae.ssid = ssid;
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node->ae.tsid = tsid;
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node->ae.tclass = tclass;
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memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
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}
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static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
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{
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struct avc_node *node, *ret = NULL;
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int hvalue;
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hvalue = avc_hash(ssid, tsid, tclass);
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list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
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if (ssid == node->ae.ssid &&
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tclass == node->ae.tclass &&
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tsid == node->ae.tsid) {
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ret = node;
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break;
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}
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}
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if (ret == NULL) {
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/* cache miss */
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goto out;
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}
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/* cache hit */
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if (atomic_read(&ret->ae.used) != 1)
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atomic_set(&ret->ae.used, 1);
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out:
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return ret;
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}
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/**
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* avc_lookup - Look up an AVC entry.
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* @ssid: source security identifier
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* @tsid: target security identifier
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* @tclass: target security class
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* @requested: requested permissions, interpreted based on @tclass
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*
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* Look up an AVC entry that is valid for the
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* @requested permissions between the SID pair
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* (@ssid, @tsid), interpreting the permissions
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* based on @tclass. If a valid AVC entry exists,
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* then this function return the avc_node.
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* Otherwise, this function returns NULL.
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*/
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static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
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{
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struct avc_node *node;
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avc_cache_stats_incr(lookups);
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node = avc_search_node(ssid, tsid, tclass);
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if (node && ((node->ae.avd.decided & requested) == requested)) {
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avc_cache_stats_incr(hits);
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goto out;
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}
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node = NULL;
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avc_cache_stats_incr(misses);
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out:
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return node;
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}
|
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|
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static int avc_latest_notif_update(int seqno, int is_insert)
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{
|
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int ret = 0;
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static DEFINE_SPINLOCK(notif_lock);
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unsigned long flag;
|
|
|
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spin_lock_irqsave(¬if_lock, flag);
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if (is_insert) {
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if (seqno < avc_cache.latest_notif) {
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printk(KERN_WARNING "avc: seqno %d < latest_notif %d\n",
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seqno, avc_cache.latest_notif);
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ret = -EAGAIN;
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}
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} else {
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if (seqno > avc_cache.latest_notif)
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avc_cache.latest_notif = seqno;
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}
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spin_unlock_irqrestore(¬if_lock, flag);
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return ret;
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}
|
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|
|
/**
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* avc_insert - Insert an AVC entry.
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* @ssid: source security identifier
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* @tsid: target security identifier
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* @tclass: target security class
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* @ae: AVC entry
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*
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* Insert an AVC entry for the SID pair
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* (@ssid, @tsid) and class @tclass.
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* The access vectors and the sequence number are
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* normally provided by the security server in
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* response to a security_compute_av() call. If the
|
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* sequence number @ae->avd.seqno is not less than the latest
|
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* revocation notification, then the function copies
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* the access vectors into a cache entry, returns
|
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* avc_node inserted. Otherwise, this function returns NULL.
|
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*/
|
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static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
|
|
{
|
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struct avc_node *pos, *node = NULL;
|
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int hvalue;
|
|
unsigned long flag;
|
|
|
|
if (avc_latest_notif_update(ae->avd.seqno, 1))
|
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goto out;
|
|
|
|
node = avc_alloc_node();
|
|
if (node) {
|
|
hvalue = avc_hash(ssid, tsid, tclass);
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avc_node_populate(node, ssid, tsid, tclass, ae);
|
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|
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spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
|
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list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
|
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if (pos->ae.ssid == ssid &&
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pos->ae.tsid == tsid &&
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pos->ae.tclass == tclass) {
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avc_node_replace(node, pos);
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goto found;
|
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}
|
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}
|
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list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
|
|
found:
|
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spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
|
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}
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out:
|
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return node;
|
|
}
|
|
|
|
static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
|
|
struct in6_addr *addr, u16 port,
|
|
char *name1, char *name2)
|
|
{
|
|
if (!ipv6_addr_any(addr))
|
|
audit_log_format(ab, " %s=%04x:%04x:%04x:%04x:%04x:"
|
|
"%04x:%04x:%04x", name1, NIP6(*addr));
|
|
if (port)
|
|
audit_log_format(ab, " %s=%d", name2, ntohs(port));
|
|
}
|
|
|
|
static inline void avc_print_ipv4_addr(struct audit_buffer *ab, u32 addr,
|
|
u16 port, char *name1, char *name2)
|
|
{
|
|
if (addr)
|
|
audit_log_format(ab, " %s=%d.%d.%d.%d", name1, NIPQUAD(addr));
|
|
if (port)
|
|
audit_log_format(ab, " %s=%d", name2, ntohs(port));
|
|
}
|
|
|
|
/**
|
|
* avc_audit - Audit the granting or denial of permissions.
|
|
* @ssid: source security identifier
|
|
* @tsid: target security identifier
|
|
* @tclass: target security class
|
|
* @requested: requested permissions
|
|
* @avd: access vector decisions
|
|
* @result: result from avc_has_perm_noaudit
|
|
* @a: auxiliary audit data
|
|
*
|
|
* Audit the granting or denial of permissions in accordance
|
|
* with the policy. This function is typically called by
|
|
* avc_has_perm() after a permission check, but can also be
|
|
* called directly by callers who use avc_has_perm_noaudit()
|
|
* in order to separate the permission check from the auditing.
|
|
* For example, this separation is useful when the permission check must
|
|
* be performed under a lock, to allow the lock to be released
|
|
* before calling the auditing code.
|
|
*/
|
|
void avc_audit(u32 ssid, u32 tsid,
|
|
u16 tclass, u32 requested,
|
|
struct av_decision *avd, int result, struct avc_audit_data *a)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
struct inode *inode = NULL;
|
|
u32 denied, audited;
|
|
struct audit_buffer *ab;
|
|
|
|
denied = requested & ~avd->allowed;
|
|
if (denied) {
|
|
audited = denied;
|
|
if (!(audited & avd->auditdeny))
|
|
return;
|
|
} else if (result) {
|
|
audited = denied = requested;
|
|
} else {
|
|
audited = requested;
|
|
if (!(audited & avd->auditallow))
|
|
return;
|
|
}
|
|
|
|
ab = audit_log_start(current->audit_context, AUDIT_AVC);
|
|
if (!ab)
|
|
return; /* audit_panic has been called */
|
|
audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted");
|
|
avc_dump_av(ab, tclass,audited);
|
|
audit_log_format(ab, " for ");
|
|
if (a && a->tsk)
|
|
tsk = a->tsk;
|
|
if (tsk && tsk->pid) {
|
|
audit_log_format(ab, " pid=%d comm=", tsk->pid);
|
|
audit_log_untrustedstring(ab, tsk->comm);
|
|
}
|
|
if (a) {
|
|
switch (a->type) {
|
|
case AVC_AUDIT_DATA_IPC:
|
|
audit_log_format(ab, " key=%d", a->u.ipc_id);
|
|
break;
|
|
case AVC_AUDIT_DATA_CAP:
|
|
audit_log_format(ab, " capability=%d", a->u.cap);
|
|
break;
|
|
case AVC_AUDIT_DATA_FS:
|
|
if (a->u.fs.dentry) {
|
|
struct dentry *dentry = a->u.fs.dentry;
|
|
if (a->u.fs.mnt)
|
|
audit_avc_path(dentry, a->u.fs.mnt);
|
|
audit_log_format(ab, " name=");
|
|
audit_log_untrustedstring(ab, dentry->d_name.name);
|
|
inode = dentry->d_inode;
|
|
} else if (a->u.fs.inode) {
|
|
struct dentry *dentry;
|
|
inode = a->u.fs.inode;
|
|
dentry = d_find_alias(inode);
|
|
if (dentry) {
|
|
audit_log_format(ab, " name=");
|
|
audit_log_untrustedstring(ab, dentry->d_name.name);
|
|
dput(dentry);
|
|
}
|
|
}
|
|
if (inode)
|
|
audit_log_format(ab, " dev=%s ino=%ld",
|
|
inode->i_sb->s_id,
|
|
inode->i_ino);
|
|
break;
|
|
case AVC_AUDIT_DATA_NET:
|
|
if (a->u.net.sk) {
|
|
struct sock *sk = a->u.net.sk;
|
|
struct unix_sock *u;
|
|
int len = 0;
|
|
char *p = NULL;
|
|
|
|
switch (sk->sk_family) {
|
|
case AF_INET: {
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
|
|
avc_print_ipv4_addr(ab, inet->rcv_saddr,
|
|
inet->sport,
|
|
"laddr", "lport");
|
|
avc_print_ipv4_addr(ab, inet->daddr,
|
|
inet->dport,
|
|
"faddr", "fport");
|
|
break;
|
|
}
|
|
case AF_INET6: {
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
struct ipv6_pinfo *inet6 = inet6_sk(sk);
|
|
|
|
avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
|
|
inet->sport,
|
|
"laddr", "lport");
|
|
avc_print_ipv6_addr(ab, &inet6->daddr,
|
|
inet->dport,
|
|
"faddr", "fport");
|
|
break;
|
|
}
|
|
case AF_UNIX:
|
|
u = unix_sk(sk);
|
|
if (u->dentry) {
|
|
audit_avc_path(u->dentry, u->mnt);
|
|
audit_log_format(ab, " name=");
|
|
audit_log_untrustedstring(ab, u->dentry->d_name.name);
|
|
break;
|
|
}
|
|
if (!u->addr)
|
|
break;
|
|
len = u->addr->len-sizeof(short);
|
|
p = &u->addr->name->sun_path[0];
|
|
audit_log_format(ab, " path=");
|
|
if (*p)
|
|
audit_log_untrustedstring(ab, p);
|
|
else
|
|
audit_log_hex(ab, p, len);
|
|
break;
|
|
}
|
|
}
|
|
|
|
switch (a->u.net.family) {
|
|
case AF_INET:
|
|
avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
|
|
a->u.net.sport,
|
|
"saddr", "src");
|
|
avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
|
|
a->u.net.dport,
|
|
"daddr", "dest");
|
|
break;
|
|
case AF_INET6:
|
|
avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
|
|
a->u.net.sport,
|
|
"saddr", "src");
|
|
avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
|
|
a->u.net.dport,
|
|
"daddr", "dest");
|
|
break;
|
|
}
|
|
if (a->u.net.netif)
|
|
audit_log_format(ab, " netif=%s",
|
|
a->u.net.netif);
|
|
break;
|
|
}
|
|
}
|
|
audit_log_format(ab, " ");
|
|
avc_dump_query(ab, ssid, tsid, tclass);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
/**
|
|
* avc_add_callback - Register a callback for security events.
|
|
* @callback: callback function
|
|
* @events: security events
|
|
* @ssid: source security identifier or %SECSID_WILD
|
|
* @tsid: target security identifier or %SECSID_WILD
|
|
* @tclass: target security class
|
|
* @perms: permissions
|
|
*
|
|
* Register a callback function for events in the set @events
|
|
* related to the SID pair (@ssid, @tsid) and
|
|
* and the permissions @perms, interpreting
|
|
* @perms based on @tclass. Returns %0 on success or
|
|
* -%ENOMEM if insufficient memory exists to add the callback.
|
|
*/
|
|
int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
|
|
u16 tclass, u32 perms,
|
|
u32 *out_retained),
|
|
u32 events, u32 ssid, u32 tsid,
|
|
u16 tclass, u32 perms)
|
|
{
|
|
struct avc_callback_node *c;
|
|
int rc = 0;
|
|
|
|
c = kmalloc(sizeof(*c), GFP_ATOMIC);
|
|
if (!c) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
c->callback = callback;
|
|
c->events = events;
|
|
c->ssid = ssid;
|
|
c->tsid = tsid;
|
|
c->perms = perms;
|
|
c->next = avc_callbacks;
|
|
avc_callbacks = c;
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static inline int avc_sidcmp(u32 x, u32 y)
|
|
{
|
|
return (x == y || x == SECSID_WILD || y == SECSID_WILD);
|
|
}
|
|
|
|
/**
|
|
* avc_update_node Update an AVC entry
|
|
* @event : Updating event
|
|
* @perms : Permission mask bits
|
|
* @ssid,@tsid,@tclass : identifier of an AVC entry
|
|
*
|
|
* if a valid AVC entry doesn't exist,this function returns -ENOENT.
|
|
* if kmalloc() called internal returns NULL, this function returns -ENOMEM.
|
|
* otherwise, this function update the AVC entry. The original AVC-entry object
|
|
* will release later by RCU.
|
|
*/
|
|
static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
|
|
{
|
|
int hvalue, rc = 0;
|
|
unsigned long flag;
|
|
struct avc_node *pos, *node, *orig = NULL;
|
|
|
|
node = avc_alloc_node();
|
|
if (!node) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
/* Lock the target slot */
|
|
hvalue = avc_hash(ssid, tsid, tclass);
|
|
spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
|
|
|
|
list_for_each_entry(pos, &avc_cache.slots[hvalue], list){
|
|
if ( ssid==pos->ae.ssid &&
|
|
tsid==pos->ae.tsid &&
|
|
tclass==pos->ae.tclass ){
|
|
orig = pos;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!orig) {
|
|
rc = -ENOENT;
|
|
avc_node_kill(node);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Copy and replace original node.
|
|
*/
|
|
|
|
avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
|
|
|
|
switch (event) {
|
|
case AVC_CALLBACK_GRANT:
|
|
node->ae.avd.allowed |= perms;
|
|
break;
|
|
case AVC_CALLBACK_TRY_REVOKE:
|
|
case AVC_CALLBACK_REVOKE:
|
|
node->ae.avd.allowed &= ~perms;
|
|
break;
|
|
case AVC_CALLBACK_AUDITALLOW_ENABLE:
|
|
node->ae.avd.auditallow |= perms;
|
|
break;
|
|
case AVC_CALLBACK_AUDITALLOW_DISABLE:
|
|
node->ae.avd.auditallow &= ~perms;
|
|
break;
|
|
case AVC_CALLBACK_AUDITDENY_ENABLE:
|
|
node->ae.avd.auditdeny |= perms;
|
|
break;
|
|
case AVC_CALLBACK_AUDITDENY_DISABLE:
|
|
node->ae.avd.auditdeny &= ~perms;
|
|
break;
|
|
}
|
|
avc_node_replace(node, orig);
|
|
out_unlock:
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* avc_ss_reset - Flush the cache and revalidate migrated permissions.
|
|
* @seqno: policy sequence number
|
|
*/
|
|
int avc_ss_reset(u32 seqno)
|
|
{
|
|
struct avc_callback_node *c;
|
|
int i, rc = 0;
|
|
unsigned long flag;
|
|
struct avc_node *node;
|
|
|
|
for (i = 0; i < AVC_CACHE_SLOTS; i++) {
|
|
spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
|
|
list_for_each_entry(node, &avc_cache.slots[i], list)
|
|
avc_node_delete(node);
|
|
spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
|
|
}
|
|
|
|
for (c = avc_callbacks; c; c = c->next) {
|
|
if (c->events & AVC_CALLBACK_RESET) {
|
|
rc = c->callback(AVC_CALLBACK_RESET,
|
|
0, 0, 0, 0, NULL);
|
|
if (rc)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
avc_latest_notif_update(seqno, 0);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* avc_has_perm_noaudit - Check permissions but perform no auditing.
|
|
* @ssid: source security identifier
|
|
* @tsid: target security identifier
|
|
* @tclass: target security class
|
|
* @requested: requested permissions, interpreted based on @tclass
|
|
* @avd: access vector decisions
|
|
*
|
|
* Check the AVC to determine whether the @requested permissions are granted
|
|
* for the SID pair (@ssid, @tsid), interpreting the permissions
|
|
* based on @tclass, and call the security server on a cache miss to obtain
|
|
* a new decision and add it to the cache. Return a copy of the decisions
|
|
* in @avd. Return %0 if all @requested permissions are granted,
|
|
* -%EACCES if any permissions are denied, or another -errno upon
|
|
* other errors. This function is typically called by avc_has_perm(),
|
|
* but may also be called directly to separate permission checking from
|
|
* auditing, e.g. in cases where a lock must be held for the check but
|
|
* should be released for the auditing.
|
|
*/
|
|
int avc_has_perm_noaudit(u32 ssid, u32 tsid,
|
|
u16 tclass, u32 requested,
|
|
struct av_decision *avd)
|
|
{
|
|
struct avc_node *node;
|
|
struct avc_entry entry, *p_ae;
|
|
int rc = 0;
|
|
u32 denied;
|
|
|
|
rcu_read_lock();
|
|
|
|
node = avc_lookup(ssid, tsid, tclass, requested);
|
|
if (!node) {
|
|
rcu_read_unlock();
|
|
rc = security_compute_av(ssid,tsid,tclass,requested,&entry.avd);
|
|
if (rc)
|
|
goto out;
|
|
rcu_read_lock();
|
|
node = avc_insert(ssid,tsid,tclass,&entry);
|
|
}
|
|
|
|
p_ae = node ? &node->ae : &entry;
|
|
|
|
if (avd)
|
|
memcpy(avd, &p_ae->avd, sizeof(*avd));
|
|
|
|
denied = requested & ~(p_ae->avd.allowed);
|
|
|
|
if (!requested || denied) {
|
|
if (selinux_enforcing)
|
|
rc = -EACCES;
|
|
else
|
|
if (node)
|
|
avc_update_node(AVC_CALLBACK_GRANT,requested,
|
|
ssid,tsid,tclass);
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* avc_has_perm - Check permissions and perform any appropriate auditing.
|
|
* @ssid: source security identifier
|
|
* @tsid: target security identifier
|
|
* @tclass: target security class
|
|
* @requested: requested permissions, interpreted based on @tclass
|
|
* @auditdata: auxiliary audit data
|
|
*
|
|
* Check the AVC to determine whether the @requested permissions are granted
|
|
* for the SID pair (@ssid, @tsid), interpreting the permissions
|
|
* based on @tclass, and call the security server on a cache miss to obtain
|
|
* a new decision and add it to the cache. Audit the granting or denial of
|
|
* permissions in accordance with the policy. Return %0 if all @requested
|
|
* permissions are granted, -%EACCES if any permissions are denied, or
|
|
* another -errno upon other errors.
|
|
*/
|
|
int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
|
|
u32 requested, struct avc_audit_data *auditdata)
|
|
{
|
|
struct av_decision avd;
|
|
int rc;
|
|
|
|
rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, &avd);
|
|
avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
|
|
return rc;
|
|
}
|