Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Implementation of the kernel access vector cache (AVC). |
| 3 | * |
| 4 | * Authors: Stephen Smalley, <sds@epoch.ncsc.mil> |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 5 | * James Morris <jmorris@redhat.com> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | * |
| 7 | * Update: KaiGai, Kohei <kaigai@ak.jp.nec.com> |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 8 | * Replaced the avc_lock spinlock by RCU. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * |
| 10 | * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License version 2, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 14 | * as published by the Free Software Foundation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | */ |
| 16 | #include <linux/types.h> |
| 17 | #include <linux/stddef.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/slab.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/dcache.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/skbuff.h> |
| 24 | #include <linux/percpu.h> |
| 25 | #include <net/sock.h> |
| 26 | #include <linux/un.h> |
| 27 | #include <net/af_unix.h> |
| 28 | #include <linux/ip.h> |
| 29 | #include <linux/audit.h> |
| 30 | #include <linux/ipv6.h> |
| 31 | #include <net/ipv6.h> |
| 32 | #include "avc.h" |
| 33 | #include "avc_ss.h" |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 34 | #include "classmap.h" |
Chad Sellers | 5c45899 | 2006-11-06 12:38:16 -0500 | [diff] [blame] | 35 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #define AVC_CACHE_SLOTS 512 |
| 37 | #define AVC_DEF_CACHE_THRESHOLD 512 |
| 38 | #define AVC_CACHE_RECLAIM 16 |
| 39 | |
| 40 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS |
Linus Torvalds | 044aea9 | 2011-05-19 18:59:47 -0700 | [diff] [blame] | 41 | #define avc_cache_stats_incr(field) this_cpu_inc(avc_cache_stats.field) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | #else |
| 43 | #define avc_cache_stats_incr(field) do {} while (0) |
| 44 | #endif |
| 45 | |
| 46 | struct avc_entry { |
| 47 | u32 ssid; |
| 48 | u32 tsid; |
| 49 | u16 tclass; |
| 50 | struct av_decision avd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | }; |
| 52 | |
| 53 | struct avc_node { |
| 54 | struct avc_entry ae; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 55 | struct hlist_node list; /* anchored in avc_cache->slots[i] */ |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 56 | struct rcu_head rhead; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | }; |
| 58 | |
| 59 | struct avc_cache { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 60 | struct hlist_head slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */ |
| 62 | atomic_t lru_hint; /* LRU hint for reclaim scan */ |
| 63 | atomic_t active_nodes; |
| 64 | u32 latest_notif; /* latest revocation notification */ |
| 65 | }; |
| 66 | |
| 67 | struct avc_callback_node { |
| 68 | int (*callback) (u32 event, u32 ssid, u32 tsid, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 69 | u16 tclass, u32 perms, |
| 70 | u32 *out_retained); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | u32 events; |
| 72 | u32 ssid; |
| 73 | u32 tsid; |
| 74 | u16 tclass; |
| 75 | u32 perms; |
| 76 | struct avc_callback_node *next; |
| 77 | }; |
| 78 | |
| 79 | /* Exported via selinufs */ |
| 80 | unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD; |
| 81 | |
| 82 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS |
| 83 | DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 }; |
| 84 | #endif |
| 85 | |
| 86 | static struct avc_cache avc_cache; |
| 87 | static struct avc_callback_node *avc_callbacks; |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 88 | static struct kmem_cache *avc_node_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | |
| 90 | static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) |
| 91 | { |
| 92 | return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1); |
| 93 | } |
| 94 | |
| 95 | /** |
| 96 | * avc_dump_av - Display an access vector in human-readable form. |
| 97 | * @tclass: target security class |
| 98 | * @av: access vector |
| 99 | */ |
KaiGai Kohei | 44c2d9b | 2009-06-18 17:26:13 +0900 | [diff] [blame] | 100 | static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | { |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 102 | const char **perms; |
| 103 | int i, perm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | |
| 105 | if (av == 0) { |
| 106 | audit_log_format(ab, " null"); |
| 107 | return; |
| 108 | } |
| 109 | |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 110 | perms = secclass_map[tclass-1].perms; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | |
| 112 | audit_log_format(ab, " {"); |
| 113 | i = 0; |
| 114 | perm = 1; |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 115 | while (i < (sizeof(av) * 8)) { |
Eric Paris | 0bce952 | 2009-11-23 16:47:23 -0500 | [diff] [blame] | 116 | if ((perm & av) && perms[i]) { |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 117 | audit_log_format(ab, " %s", perms[i]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | av &= ~perm; |
| 119 | } |
| 120 | i++; |
| 121 | perm <<= 1; |
| 122 | } |
| 123 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | if (av) |
| 125 | audit_log_format(ab, " 0x%x", av); |
| 126 | |
| 127 | audit_log_format(ab, " }"); |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * avc_dump_query - Display a SID pair and a class in human-readable form. |
| 132 | * @ssid: source security identifier |
| 133 | * @tsid: target security identifier |
| 134 | * @tclass: target security class |
| 135 | */ |
| 136 | static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass) |
| 137 | { |
| 138 | int rc; |
| 139 | char *scontext; |
| 140 | u32 scontext_len; |
| 141 | |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 142 | rc = security_sid_to_context(ssid, &scontext, &scontext_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | if (rc) |
| 144 | audit_log_format(ab, "ssid=%d", ssid); |
| 145 | else { |
| 146 | audit_log_format(ab, "scontext=%s", scontext); |
| 147 | kfree(scontext); |
| 148 | } |
| 149 | |
| 150 | rc = security_sid_to_context(tsid, &scontext, &scontext_len); |
| 151 | if (rc) |
| 152 | audit_log_format(ab, " tsid=%d", tsid); |
| 153 | else { |
| 154 | audit_log_format(ab, " tcontext=%s", scontext); |
| 155 | kfree(scontext); |
| 156 | } |
Stephen Smalley | a764ae4 | 2007-03-26 13:36:26 -0400 | [diff] [blame] | 157 | |
Stephen Smalley | c6d3aaa | 2009-09-30 13:37:50 -0400 | [diff] [blame] | 158 | BUG_ON(tclass >= ARRAY_SIZE(secclass_map)); |
| 159 | audit_log_format(ab, " tclass=%s", secclass_map[tclass-1].name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | } |
| 161 | |
| 162 | /** |
| 163 | * avc_init - Initialize the AVC. |
| 164 | * |
| 165 | * Initialize the access vector cache. |
| 166 | */ |
| 167 | void __init avc_init(void) |
| 168 | { |
| 169 | int i; |
| 170 | |
| 171 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 172 | INIT_HLIST_HEAD(&avc_cache.slots[i]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | spin_lock_init(&avc_cache.slots_lock[i]); |
| 174 | } |
| 175 | atomic_set(&avc_cache.active_nodes, 0); |
| 176 | atomic_set(&avc_cache.lru_hint, 0); |
| 177 | |
| 178 | avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node), |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 179 | 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | |
David Woodhouse | 9ad9ad3 | 2005-06-22 15:04:33 +0100 | [diff] [blame] | 181 | audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | } |
| 183 | |
| 184 | int avc_get_hash_stats(char *page) |
| 185 | { |
| 186 | int i, chain_len, max_chain_len, slots_used; |
| 187 | struct avc_node *node; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 188 | struct hlist_head *head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | |
| 190 | rcu_read_lock(); |
| 191 | |
| 192 | slots_used = 0; |
| 193 | max_chain_len = 0; |
| 194 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 195 | head = &avc_cache.slots[i]; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 196 | if (!hlist_empty(head)) { |
| 197 | struct hlist_node *next; |
| 198 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | slots_used++; |
| 200 | chain_len = 0; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 201 | hlist_for_each_entry_rcu(node, next, head, list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | chain_len++; |
| 203 | if (chain_len > max_chain_len) |
| 204 | max_chain_len = chain_len; |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | rcu_read_unlock(); |
| 209 | |
| 210 | return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n" |
| 211 | "longest chain: %d\n", |
| 212 | atomic_read(&avc_cache.active_nodes), |
| 213 | slots_used, AVC_CACHE_SLOTS, max_chain_len); |
| 214 | } |
| 215 | |
| 216 | static void avc_node_free(struct rcu_head *rhead) |
| 217 | { |
| 218 | struct avc_node *node = container_of(rhead, struct avc_node, rhead); |
| 219 | kmem_cache_free(avc_node_cachep, node); |
| 220 | avc_cache_stats_incr(frees); |
| 221 | } |
| 222 | |
| 223 | static void avc_node_delete(struct avc_node *node) |
| 224 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 225 | hlist_del_rcu(&node->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | call_rcu(&node->rhead, avc_node_free); |
| 227 | atomic_dec(&avc_cache.active_nodes); |
| 228 | } |
| 229 | |
| 230 | static void avc_node_kill(struct avc_node *node) |
| 231 | { |
| 232 | kmem_cache_free(avc_node_cachep, node); |
| 233 | avc_cache_stats_incr(frees); |
| 234 | atomic_dec(&avc_cache.active_nodes); |
| 235 | } |
| 236 | |
| 237 | static void avc_node_replace(struct avc_node *new, struct avc_node *old) |
| 238 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 239 | hlist_replace_rcu(&old->list, &new->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | call_rcu(&old->rhead, avc_node_free); |
| 241 | atomic_dec(&avc_cache.active_nodes); |
| 242 | } |
| 243 | |
| 244 | static inline int avc_reclaim_node(void) |
| 245 | { |
| 246 | struct avc_node *node; |
| 247 | int hvalue, try, ecx; |
| 248 | unsigned long flags; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 249 | struct hlist_head *head; |
| 250 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 251 | spinlock_t *lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 253 | for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 255 | head = &avc_cache.slots[hvalue]; |
| 256 | lock = &avc_cache.slots_lock[hvalue]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 258 | if (!spin_trylock_irqsave(lock, flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | continue; |
| 260 | |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 261 | rcu_read_lock(); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 262 | hlist_for_each_entry(node, next, head, list) { |
Eric Paris | 906d27d | 2009-02-12 14:50:43 -0500 | [diff] [blame] | 263 | avc_node_delete(node); |
| 264 | avc_cache_stats_incr(reclaims); |
| 265 | ecx++; |
| 266 | if (ecx >= AVC_CACHE_RECLAIM) { |
| 267 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 268 | spin_unlock_irqrestore(lock, flags); |
Eric Paris | 906d27d | 2009-02-12 14:50:43 -0500 | [diff] [blame] | 269 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | } |
| 271 | } |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 272 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 273 | spin_unlock_irqrestore(lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | } |
| 275 | out: |
| 276 | return ecx; |
| 277 | } |
| 278 | |
| 279 | static struct avc_node *avc_alloc_node(void) |
| 280 | { |
| 281 | struct avc_node *node; |
| 282 | |
Robert P. J. Day | c376222 | 2007-02-10 01:45:03 -0800 | [diff] [blame] | 283 | node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | if (!node) |
| 285 | goto out; |
| 286 | |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 287 | INIT_HLIST_NODE(&node->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | avc_cache_stats_incr(allocations); |
| 289 | |
| 290 | if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold) |
| 291 | avc_reclaim_node(); |
| 292 | |
| 293 | out: |
| 294 | return node; |
| 295 | } |
| 296 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 297 | static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | { |
| 299 | node->ae.ssid = ssid; |
| 300 | node->ae.tsid = tsid; |
| 301 | node->ae.tclass = tclass; |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 302 | memcpy(&node->ae.avd, avd, sizeof(node->ae.avd)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 303 | } |
| 304 | |
| 305 | static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass) |
| 306 | { |
| 307 | struct avc_node *node, *ret = NULL; |
| 308 | int hvalue; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 309 | struct hlist_head *head; |
| 310 | struct hlist_node *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | |
| 312 | hvalue = avc_hash(ssid, tsid, tclass); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 313 | head = &avc_cache.slots[hvalue]; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 314 | hlist_for_each_entry_rcu(node, next, head, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | if (ssid == node->ae.ssid && |
| 316 | tclass == node->ae.tclass && |
| 317 | tsid == node->ae.tsid) { |
| 318 | ret = node; |
| 319 | break; |
| 320 | } |
| 321 | } |
| 322 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | return ret; |
| 324 | } |
| 325 | |
| 326 | /** |
| 327 | * avc_lookup - Look up an AVC entry. |
| 328 | * @ssid: source security identifier |
| 329 | * @tsid: target security identifier |
| 330 | * @tclass: target security class |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | * |
| 332 | * Look up an AVC entry that is valid for the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | * (@ssid, @tsid), interpreting the permissions |
| 334 | * based on @tclass. If a valid AVC entry exists, |
Justin P. Mattock | 6382dc3 | 2010-01-14 23:03:18 -0800 | [diff] [blame] | 335 | * then this function returns the avc_node. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | * Otherwise, this function returns NULL. |
| 337 | */ |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 338 | static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | { |
| 340 | struct avc_node *node; |
| 341 | |
| 342 | avc_cache_stats_incr(lookups); |
| 343 | node = avc_search_node(ssid, tsid, tclass); |
| 344 | |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 345 | if (node) |
Linus Torvalds | 257313b | 2011-05-19 21:22:53 -0700 | [diff] [blame] | 346 | return node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | |
Linus Torvalds | 257313b | 2011-05-19 21:22:53 -0700 | [diff] [blame] | 348 | avc_cache_stats_incr(misses); |
| 349 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | } |
| 351 | |
| 352 | static int avc_latest_notif_update(int seqno, int is_insert) |
| 353 | { |
| 354 | int ret = 0; |
| 355 | static DEFINE_SPINLOCK(notif_lock); |
| 356 | unsigned long flag; |
| 357 | |
| 358 | spin_lock_irqsave(¬if_lock, flag); |
| 359 | if (is_insert) { |
| 360 | if (seqno < avc_cache.latest_notif) { |
Eric Paris | 744ba35 | 2008-04-17 11:52:44 -0400 | [diff] [blame] | 361 | printk(KERN_WARNING "SELinux: avc: seqno %d < latest_notif %d\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | seqno, avc_cache.latest_notif); |
| 363 | ret = -EAGAIN; |
| 364 | } |
| 365 | } else { |
| 366 | if (seqno > avc_cache.latest_notif) |
| 367 | avc_cache.latest_notif = seqno; |
| 368 | } |
| 369 | spin_unlock_irqrestore(¬if_lock, flag); |
| 370 | |
| 371 | return ret; |
| 372 | } |
| 373 | |
| 374 | /** |
| 375 | * avc_insert - Insert an AVC entry. |
| 376 | * @ssid: source security identifier |
| 377 | * @tsid: target security identifier |
| 378 | * @tclass: target security class |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 379 | * @avd: resulting av decision |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | * |
| 381 | * Insert an AVC entry for the SID pair |
| 382 | * (@ssid, @tsid) and class @tclass. |
| 383 | * The access vectors and the sequence number are |
| 384 | * normally provided by the security server in |
| 385 | * response to a security_compute_av() call. If the |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 386 | * sequence number @avd->seqno is not less than the latest |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | * revocation notification, then the function copies |
| 388 | * the access vectors into a cache entry, returns |
| 389 | * avc_node inserted. Otherwise, this function returns NULL. |
| 390 | */ |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 391 | static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | { |
| 393 | struct avc_node *pos, *node = NULL; |
| 394 | int hvalue; |
| 395 | unsigned long flag; |
| 396 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 397 | if (avc_latest_notif_update(avd->seqno, 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | goto out; |
| 399 | |
| 400 | node = avc_alloc_node(); |
| 401 | if (node) { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 402 | struct hlist_head *head; |
| 403 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 404 | spinlock_t *lock; |
| 405 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | hvalue = avc_hash(ssid, tsid, tclass); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 407 | avc_node_populate(node, ssid, tsid, tclass, avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 409 | head = &avc_cache.slots[hvalue]; |
| 410 | lock = &avc_cache.slots_lock[hvalue]; |
| 411 | |
| 412 | spin_lock_irqsave(lock, flag); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 413 | hlist_for_each_entry(pos, next, head, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | if (pos->ae.ssid == ssid && |
| 415 | pos->ae.tsid == tsid && |
| 416 | pos->ae.tclass == tclass) { |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 417 | avc_node_replace(node, pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | goto found; |
| 419 | } |
| 420 | } |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 421 | hlist_add_head_rcu(&node->list, head); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | found: |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 423 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | } |
| 425 | out: |
| 426 | return node; |
| 427 | } |
| 428 | |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 429 | /** |
| 430 | * avc_audit_pre_callback - SELinux specific information |
| 431 | * will be called by generic audit code |
| 432 | * @ab: the audit buffer |
| 433 | * @a: audit_data |
| 434 | */ |
| 435 | static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 437 | struct common_audit_data *ad = a; |
| 438 | audit_log_format(ab, "avc: %s ", |
Eric Paris | 3f0882c | 2012-04-03 09:38:00 -0700 | [diff] [blame] | 439 | ad->selinux_audit_data->slad->denied ? "denied" : "granted"); |
| 440 | avc_dump_av(ab, ad->selinux_audit_data->slad->tclass, |
| 441 | ad->selinux_audit_data->slad->audited); |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 442 | audit_log_format(ab, " for "); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | } |
| 444 | |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 445 | /** |
| 446 | * avc_audit_post_callback - SELinux specific information |
| 447 | * will be called by generic audit code |
| 448 | * @ab: the audit buffer |
| 449 | * @a: audit_data |
| 450 | */ |
| 451 | static void avc_audit_post_callback(struct audit_buffer *ab, void *a) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 453 | struct common_audit_data *ad = a; |
| 454 | audit_log_format(ab, " "); |
Eric Paris | 3f0882c | 2012-04-03 09:38:00 -0700 | [diff] [blame] | 455 | avc_dump_query(ab, ad->selinux_audit_data->slad->ssid, |
| 456 | ad->selinux_audit_data->slad->tsid, |
| 457 | ad->selinux_audit_data->slad->tclass); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | } |
| 459 | |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 460 | /* This is the slow part of avc audit with big stack footprint */ |
| 461 | static noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass, |
| 462 | u32 requested, u32 audited, u32 denied, |
Eric Paris | f8294f1 | 2012-04-02 13:15:55 -0400 | [diff] [blame] | 463 | struct common_audit_data *a, |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 464 | unsigned flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 466 | struct common_audit_data stack_data; |
Eric Paris | 3b3b0e4 | 2012-04-03 09:37:02 -0700 | [diff] [blame] | 467 | struct selinux_audit_data sad = {0,}; |
Eric Paris | 3f0882c | 2012-04-03 09:38:00 -0700 | [diff] [blame] | 468 | struct selinux_late_audit_data slad; |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 469 | |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 470 | if (!a) { |
| 471 | a = &stack_data; |
Eric Paris | cb84aa9 | 2010-04-27 17:20:38 -0400 | [diff] [blame] | 472 | COMMON_AUDIT_DATA_INIT(a, NONE); |
Eric Paris | 3b3b0e4 | 2012-04-03 09:37:02 -0700 | [diff] [blame] | 473 | a->selinux_audit_data = &sad; |
James Morris | be940d6 | 2009-07-13 10:39:36 +1000 | [diff] [blame] | 474 | } |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 475 | |
| 476 | /* |
| 477 | * When in a RCU walk do the audit on the RCU retry. This is because |
| 478 | * the collection of the dname in an inode audit message is not RCU |
| 479 | * safe. Note this may drop some audits when the situation changes |
| 480 | * during retry. However this is logically just as if the operation |
| 481 | * happened a little later. |
| 482 | */ |
Eric Paris | f48b739 | 2011-04-25 12:54:27 -0400 | [diff] [blame] | 483 | if ((a->type == LSM_AUDIT_DATA_INODE) && |
Al Viro | cf1dd1d | 2011-06-20 19:44:08 -0400 | [diff] [blame] | 484 | (flags & MAY_NOT_BLOCK)) |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 485 | return -ECHILD; |
| 486 | |
Eric Paris | 3f0882c | 2012-04-03 09:38:00 -0700 | [diff] [blame] | 487 | slad.tclass = tclass; |
| 488 | slad.requested = requested; |
| 489 | slad.ssid = ssid; |
| 490 | slad.tsid = tsid; |
| 491 | slad.audited = audited; |
| 492 | slad.denied = denied; |
| 493 | |
| 494 | a->selinux_audit_data->slad = &slad; |
Linus Torvalds | b61c37f | 2012-04-02 15:48:12 -0700 | [diff] [blame] | 495 | common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback); |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 496 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | } |
| 498 | |
| 499 | /** |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 500 | * avc_audit - Audit the granting or denial of permissions. |
| 501 | * @ssid: source security identifier |
| 502 | * @tsid: target security identifier |
| 503 | * @tclass: target security class |
| 504 | * @requested: requested permissions |
| 505 | * @avd: access vector decisions |
| 506 | * @result: result from avc_has_perm_noaudit |
| 507 | * @a: auxiliary audit data |
| 508 | * @flags: VFS walk flags |
| 509 | * |
| 510 | * Audit the granting or denial of permissions in accordance |
| 511 | * with the policy. This function is typically called by |
| 512 | * avc_has_perm() after a permission check, but can also be |
| 513 | * called directly by callers who use avc_has_perm_noaudit() |
| 514 | * in order to separate the permission check from the auditing. |
| 515 | * For example, this separation is useful when the permission check must |
| 516 | * be performed under a lock, to allow the lock to be released |
| 517 | * before calling the auditing code. |
| 518 | */ |
Linus Torvalds | cdb0f9a | 2012-03-31 11:12:57 -0700 | [diff] [blame] | 519 | inline int avc_audit(u32 ssid, u32 tsid, |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 520 | u16 tclass, u32 requested, |
| 521 | struct av_decision *avd, int result, struct common_audit_data *a, |
| 522 | unsigned flags) |
| 523 | { |
| 524 | u32 denied, audited; |
| 525 | denied = requested & ~avd->allowed; |
| 526 | if (unlikely(denied)) { |
| 527 | audited = denied & avd->auditdeny; |
| 528 | /* |
Eric Paris | 3b3b0e4 | 2012-04-03 09:37:02 -0700 | [diff] [blame] | 529 | * a->selinux_audit_data->auditdeny is TRICKY! Setting a bit in |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 530 | * this field means that ANY denials should NOT be audited if |
| 531 | * the policy contains an explicit dontaudit rule for that |
| 532 | * permission. Take notice that this is unrelated to the |
| 533 | * actual permissions that were denied. As an example lets |
| 534 | * assume: |
| 535 | * |
| 536 | * denied == READ |
| 537 | * avd.auditdeny & ACCESS == 0 (not set means explicit rule) |
Eric Paris | 3b3b0e4 | 2012-04-03 09:37:02 -0700 | [diff] [blame] | 538 | * selinux_audit_data->auditdeny & ACCESS == 1 |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 539 | * |
| 540 | * We will NOT audit the denial even though the denied |
| 541 | * permission was READ and the auditdeny checks were for |
| 542 | * ACCESS |
| 543 | */ |
| 544 | if (a && |
Eric Paris | 3b3b0e4 | 2012-04-03 09:37:02 -0700 | [diff] [blame] | 545 | a->selinux_audit_data->auditdeny && |
| 546 | !(a->selinux_audit_data->auditdeny & avd->auditdeny)) |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 547 | audited = 0; |
| 548 | } else if (result) |
| 549 | audited = denied = requested; |
| 550 | else |
| 551 | audited = requested & avd->auditallow; |
| 552 | if (likely(!audited)) |
| 553 | return 0; |
| 554 | |
| 555 | return slow_avc_audit(ssid, tsid, tclass, |
| 556 | requested, audited, denied, |
Eric Paris | f8294f1 | 2012-04-02 13:15:55 -0400 | [diff] [blame] | 557 | a, flags); |
Linus Torvalds | 48aab2f | 2012-03-22 17:01:41 -0700 | [diff] [blame] | 558 | } |
| 559 | |
| 560 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | * avc_add_callback - Register a callback for security events. |
| 562 | * @callback: callback function |
| 563 | * @events: security events |
| 564 | * @ssid: source security identifier or %SECSID_WILD |
| 565 | * @tsid: target security identifier or %SECSID_WILD |
| 566 | * @tclass: target security class |
| 567 | * @perms: permissions |
| 568 | * |
| 569 | * Register a callback function for events in the set @events |
Justin P. Mattock | 6382dc3 | 2010-01-14 23:03:18 -0800 | [diff] [blame] | 570 | * related to the SID pair (@ssid, @tsid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | * and the permissions @perms, interpreting |
| 572 | * @perms based on @tclass. Returns %0 on success or |
| 573 | * -%ENOMEM if insufficient memory exists to add the callback. |
| 574 | */ |
| 575 | int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 576 | u16 tclass, u32 perms, |
| 577 | u32 *out_retained), |
| 578 | u32 events, u32 ssid, u32 tsid, |
| 579 | u16 tclass, u32 perms) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | { |
| 581 | struct avc_callback_node *c; |
| 582 | int rc = 0; |
| 583 | |
| 584 | c = kmalloc(sizeof(*c), GFP_ATOMIC); |
| 585 | if (!c) { |
| 586 | rc = -ENOMEM; |
| 587 | goto out; |
| 588 | } |
| 589 | |
| 590 | c->callback = callback; |
| 591 | c->events = events; |
| 592 | c->ssid = ssid; |
| 593 | c->tsid = tsid; |
| 594 | c->perms = perms; |
| 595 | c->next = avc_callbacks; |
| 596 | avc_callbacks = c; |
| 597 | out: |
| 598 | return rc; |
| 599 | } |
| 600 | |
| 601 | static inline int avc_sidcmp(u32 x, u32 y) |
| 602 | { |
| 603 | return (x == y || x == SECSID_WILD || y == SECSID_WILD); |
| 604 | } |
| 605 | |
| 606 | /** |
| 607 | * avc_update_node Update an AVC entry |
| 608 | * @event : Updating event |
| 609 | * @perms : Permission mask bits |
| 610 | * @ssid,@tsid,@tclass : identifier of an AVC entry |
Eric Paris | a5dda68 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 611 | * @seqno : sequence number when decision was made |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | * |
| 613 | * if a valid AVC entry doesn't exist,this function returns -ENOENT. |
| 614 | * if kmalloc() called internal returns NULL, this function returns -ENOMEM. |
Justin P. Mattock | 6382dc3 | 2010-01-14 23:03:18 -0800 | [diff] [blame] | 615 | * otherwise, this function updates the AVC entry. The original AVC-entry object |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | * will release later by RCU. |
| 617 | */ |
Eric Paris | a5dda68 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 618 | static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, |
| 619 | u32 seqno) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | { |
| 621 | int hvalue, rc = 0; |
| 622 | unsigned long flag; |
| 623 | struct avc_node *pos, *node, *orig = NULL; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 624 | struct hlist_head *head; |
| 625 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 626 | spinlock_t *lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | |
| 628 | node = avc_alloc_node(); |
| 629 | if (!node) { |
| 630 | rc = -ENOMEM; |
| 631 | goto out; |
| 632 | } |
| 633 | |
| 634 | /* Lock the target slot */ |
| 635 | hvalue = avc_hash(ssid, tsid, tclass); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 637 | head = &avc_cache.slots[hvalue]; |
| 638 | lock = &avc_cache.slots_lock[hvalue]; |
| 639 | |
| 640 | spin_lock_irqsave(lock, flag); |
| 641 | |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 642 | hlist_for_each_entry(pos, next, head, list) { |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 643 | if (ssid == pos->ae.ssid && |
| 644 | tsid == pos->ae.tsid && |
Eric Paris | a5dda68 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 645 | tclass == pos->ae.tclass && |
| 646 | seqno == pos->ae.avd.seqno){ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | orig = pos; |
| 648 | break; |
| 649 | } |
| 650 | } |
| 651 | |
| 652 | if (!orig) { |
| 653 | rc = -ENOENT; |
| 654 | avc_node_kill(node); |
| 655 | goto out_unlock; |
| 656 | } |
| 657 | |
| 658 | /* |
| 659 | * Copy and replace original node. |
| 660 | */ |
| 661 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 662 | avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | |
| 664 | switch (event) { |
| 665 | case AVC_CALLBACK_GRANT: |
| 666 | node->ae.avd.allowed |= perms; |
| 667 | break; |
| 668 | case AVC_CALLBACK_TRY_REVOKE: |
| 669 | case AVC_CALLBACK_REVOKE: |
| 670 | node->ae.avd.allowed &= ~perms; |
| 671 | break; |
| 672 | case AVC_CALLBACK_AUDITALLOW_ENABLE: |
| 673 | node->ae.avd.auditallow |= perms; |
| 674 | break; |
| 675 | case AVC_CALLBACK_AUDITALLOW_DISABLE: |
| 676 | node->ae.avd.auditallow &= ~perms; |
| 677 | break; |
| 678 | case AVC_CALLBACK_AUDITDENY_ENABLE: |
| 679 | node->ae.avd.auditdeny |= perms; |
| 680 | break; |
| 681 | case AVC_CALLBACK_AUDITDENY_DISABLE: |
| 682 | node->ae.avd.auditdeny &= ~perms; |
| 683 | break; |
| 684 | } |
| 685 | avc_node_replace(node, orig); |
| 686 | out_unlock: |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 687 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | out: |
| 689 | return rc; |
| 690 | } |
| 691 | |
| 692 | /** |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 693 | * avc_flush - Flush the cache |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | */ |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 695 | static void avc_flush(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 697 | struct hlist_head *head; |
| 698 | struct hlist_node *next; |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 699 | struct avc_node *node; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 700 | spinlock_t *lock; |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 701 | unsigned long flag; |
| 702 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | |
| 704 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 705 | head = &avc_cache.slots[i]; |
| 706 | lock = &avc_cache.slots_lock[i]; |
| 707 | |
| 708 | spin_lock_irqsave(lock, flag); |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 709 | /* |
| 710 | * With preemptable RCU, the outer spinlock does not |
| 711 | * prevent RCU grace periods from ending. |
| 712 | */ |
| 713 | rcu_read_lock(); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 714 | hlist_for_each_entry(node, next, head, list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | avc_node_delete(node); |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 716 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 717 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | } |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 719 | } |
| 720 | |
| 721 | /** |
| 722 | * avc_ss_reset - Flush the cache and revalidate migrated permissions. |
| 723 | * @seqno: policy sequence number |
| 724 | */ |
| 725 | int avc_ss_reset(u32 seqno) |
| 726 | { |
| 727 | struct avc_callback_node *c; |
| 728 | int rc = 0, tmprc; |
| 729 | |
| 730 | avc_flush(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | |
| 732 | for (c = avc_callbacks; c; c = c->next) { |
| 733 | if (c->events & AVC_CALLBACK_RESET) { |
Darrel Goeddel | 376bd9c | 2006-02-24 15:44:05 -0600 | [diff] [blame] | 734 | tmprc = c->callback(AVC_CALLBACK_RESET, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 735 | 0, 0, 0, 0, NULL); |
Darrel Goeddel | 376bd9c | 2006-02-24 15:44:05 -0600 | [diff] [blame] | 736 | /* save the first error encountered for the return |
| 737 | value and continue processing the callbacks */ |
| 738 | if (!rc) |
| 739 | rc = tmprc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | } |
| 741 | } |
| 742 | |
| 743 | avc_latest_notif_update(seqno, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | return rc; |
| 745 | } |
| 746 | |
Linus Torvalds | a554bea | 2012-03-31 10:58:08 -0700 | [diff] [blame] | 747 | /* |
| 748 | * Slow-path helper function for avc_has_perm_noaudit, |
| 749 | * when the avc_node lookup fails. We get called with |
| 750 | * the RCU read lock held, and need to return with it |
| 751 | * still held, but drop if for the security compute. |
| 752 | * |
| 753 | * Don't inline this, since it's the slow-path and just |
| 754 | * results in a bigger stack frame. |
| 755 | */ |
| 756 | static noinline struct avc_node *avc_compute_av(u32 ssid, u32 tsid, |
| 757 | u16 tclass, struct av_decision *avd) |
| 758 | { |
| 759 | rcu_read_unlock(); |
| 760 | security_compute_av(ssid, tsid, tclass, avd); |
| 761 | rcu_read_lock(); |
| 762 | return avc_insert(ssid, tsid, tclass, avd); |
| 763 | } |
| 764 | |
| 765 | static noinline int avc_denied(u32 ssid, u32 tsid, |
| 766 | u16 tclass, u32 requested, |
| 767 | unsigned flags, |
| 768 | struct av_decision *avd) |
| 769 | { |
| 770 | if (flags & AVC_STRICT) |
| 771 | return -EACCES; |
| 772 | |
| 773 | if (selinux_enforcing && !(avd->flags & AVD_FLAGS_PERMISSIVE)) |
| 774 | return -EACCES; |
| 775 | |
| 776 | avc_update_node(AVC_CALLBACK_GRANT, requested, ssid, |
| 777 | tsid, tclass, avd->seqno); |
| 778 | return 0; |
| 779 | } |
| 780 | |
| 781 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | /** |
| 783 | * avc_has_perm_noaudit - Check permissions but perform no auditing. |
| 784 | * @ssid: source security identifier |
| 785 | * @tsid: target security identifier |
| 786 | * @tclass: target security class |
| 787 | * @requested: requested permissions, interpreted based on @tclass |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 788 | * @flags: AVC_STRICT or 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | * @avd: access vector decisions |
| 790 | * |
| 791 | * Check the AVC to determine whether the @requested permissions are granted |
| 792 | * for the SID pair (@ssid, @tsid), interpreting the permissions |
| 793 | * based on @tclass, and call the security server on a cache miss to obtain |
| 794 | * a new decision and add it to the cache. Return a copy of the decisions |
| 795 | * in @avd. Return %0 if all @requested permissions are granted, |
| 796 | * -%EACCES if any permissions are denied, or another -errno upon |
| 797 | * other errors. This function is typically called by avc_has_perm(), |
| 798 | * but may also be called directly to separate permission checking from |
| 799 | * auditing, e.g. in cases where a lock must be held for the check but |
| 800 | * should be released for the auditing. |
| 801 | */ |
Linus Torvalds | cdb0f9a | 2012-03-31 11:12:57 -0700 | [diff] [blame] | 802 | inline int avc_has_perm_noaudit(u32 ssid, u32 tsid, |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 803 | u16 tclass, u32 requested, |
| 804 | unsigned flags, |
Linus Torvalds | f01e1af | 2011-05-24 13:48:51 -0700 | [diff] [blame] | 805 | struct av_decision *avd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 806 | { |
| 807 | struct avc_node *node; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | int rc = 0; |
| 809 | u32 denied; |
| 810 | |
Eric Paris | eda4f69 | 2008-03-11 14:19:34 -0400 | [diff] [blame] | 811 | BUG_ON(!requested); |
| 812 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | rcu_read_lock(); |
| 814 | |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 815 | node = avc_lookup(ssid, tsid, tclass); |
Linus Torvalds | 257313b | 2011-05-19 21:22:53 -0700 | [diff] [blame] | 816 | if (unlikely(!node)) { |
Linus Torvalds | a554bea | 2012-03-31 10:58:08 -0700 | [diff] [blame] | 817 | node = avc_compute_av(ssid, tsid, tclass, avd); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 818 | } else { |
Linus Torvalds | f01e1af | 2011-05-24 13:48:51 -0700 | [diff] [blame] | 819 | memcpy(avd, &node->ae.avd, sizeof(*avd)); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 820 | avd = &node->ae.avd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | } |
| 822 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 823 | denied = requested & ~(avd->allowed); |
Linus Torvalds | a554bea | 2012-03-31 10:58:08 -0700 | [diff] [blame] | 824 | if (unlikely(denied)) |
| 825 | rc = avc_denied(ssid, tsid, tclass, requested, flags, avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | |
| 827 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | return rc; |
| 829 | } |
| 830 | |
| 831 | /** |
| 832 | * avc_has_perm - Check permissions and perform any appropriate auditing. |
| 833 | * @ssid: source security identifier |
| 834 | * @tsid: target security identifier |
| 835 | * @tclass: target security class |
| 836 | * @requested: requested permissions, interpreted based on @tclass |
| 837 | * @auditdata: auxiliary audit data |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 838 | * @flags: VFS walk flags |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | * |
| 840 | * Check the AVC to determine whether the @requested permissions are granted |
| 841 | * for the SID pair (@ssid, @tsid), interpreting the permissions |
| 842 | * based on @tclass, and call the security server on a cache miss to obtain |
| 843 | * a new decision and add it to the cache. Audit the granting or denial of |
| 844 | * permissions in accordance with the policy. Return %0 if all @requested |
| 845 | * permissions are granted, -%EACCES if any permissions are denied, or |
| 846 | * another -errno upon other errors. |
| 847 | */ |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 848 | int avc_has_perm_flags(u32 ssid, u32 tsid, u16 tclass, |
| 849 | u32 requested, struct common_audit_data *auditdata, |
| 850 | unsigned flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | { |
| 852 | struct av_decision avd; |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 853 | int rc, rc2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 854 | |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 855 | rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd); |
Eric Paris | 9ade0cf | 2011-04-25 16:26:29 -0400 | [diff] [blame] | 856 | |
| 857 | rc2 = avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata, |
| 858 | flags); |
| 859 | if (rc2) |
| 860 | return rc2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | return rc; |
| 862 | } |
Yuichi Nakamura | 788e7dd | 2007-09-14 09:27:07 +0900 | [diff] [blame] | 863 | |
| 864 | u32 avc_policy_seqno(void) |
| 865 | { |
| 866 | return avc_cache.latest_notif; |
| 867 | } |
Thomas Liu | 89c8657 | 2009-06-24 17:58:05 -0400 | [diff] [blame] | 868 | |
| 869 | void avc_disable(void) |
| 870 | { |
Eric Paris | 5224ee0 | 2009-09-20 21:21:10 -0400 | [diff] [blame] | 871 | /* |
| 872 | * If you are looking at this because you have realized that we are |
| 873 | * not destroying the avc_node_cachep it might be easy to fix, but |
| 874 | * I don't know the memory barrier semantics well enough to know. It's |
| 875 | * possible that some other task dereferenced security_ops when |
| 876 | * it still pointed to selinux operations. If that is the case it's |
| 877 | * possible that it is about to use the avc and is about to need the |
| 878 | * avc_node_cachep. I know I could wrap the security.c security_ops call |
| 879 | * in an rcu_lock, but seriously, it's not worth it. Instead I just flush |
| 880 | * the cache and get that memory back. |
| 881 | */ |
| 882 | if (avc_node_cachep) { |
| 883 | avc_flush(); |
| 884 | /* kmem_cache_destroy(avc_node_cachep); */ |
| 885 | } |
Thomas Liu | 89c8657 | 2009-06-24 17:58:05 -0400 | [diff] [blame] | 886 | } |