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" |
| 34 | |
Chad Sellers | 5c45899 | 2006-11-06 12:38:16 -0500 | [diff] [blame] | 35 | static const struct av_perm_to_string av_perm_to_string[] = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #define S_(c, v, s) { c, v, s }, |
| 37 | #include "av_perm_to_string.h" |
| 38 | #undef S_ |
| 39 | }; |
| 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | static const char *class_to_string[] = { |
| 42 | #define S_(s) s, |
| 43 | #include "class_to_string.h" |
| 44 | #undef S_ |
| 45 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 47 | #define TB_(s) static const char *s[] = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | #define TE_(s) }; |
| 49 | #define S_(s) s, |
| 50 | #include "common_perm_to_string.h" |
| 51 | #undef TB_ |
| 52 | #undef TE_ |
| 53 | #undef S_ |
| 54 | |
Chad Sellers | 5c45899 | 2006-11-06 12:38:16 -0500 | [diff] [blame] | 55 | static const struct av_inherit av_inherit[] = { |
Eric Paris | 76f7ba3 | 2009-01-02 17:40:06 -0500 | [diff] [blame] | 56 | #define S_(c, i, b) { .tclass = c,\ |
| 57 | .common_pts = common_##i##_perm_to_string,\ |
| 58 | .common_base = b }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | #include "av_inherit.h" |
| 60 | #undef S_ |
| 61 | }; |
| 62 | |
Chad Sellers | 5c45899 | 2006-11-06 12:38:16 -0500 | [diff] [blame] | 63 | const struct selinux_class_perm selinux_class_perm = { |
Eric Paris | 76f7ba3 | 2009-01-02 17:40:06 -0500 | [diff] [blame] | 64 | .av_perm_to_string = av_perm_to_string, |
| 65 | .av_pts_len = ARRAY_SIZE(av_perm_to_string), |
| 66 | .class_to_string = class_to_string, |
| 67 | .cts_len = ARRAY_SIZE(class_to_string), |
| 68 | .av_inherit = av_inherit, |
| 69 | .av_inherit_len = ARRAY_SIZE(av_inherit) |
Chad Sellers | 5c45899 | 2006-11-06 12:38:16 -0500 | [diff] [blame] | 70 | }; |
| 71 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | #define AVC_CACHE_SLOTS 512 |
| 73 | #define AVC_DEF_CACHE_THRESHOLD 512 |
| 74 | #define AVC_CACHE_RECLAIM 16 |
| 75 | |
| 76 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 77 | #define avc_cache_stats_incr(field) \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | do { \ |
| 79 | per_cpu(avc_cache_stats, get_cpu()).field++; \ |
| 80 | put_cpu(); \ |
| 81 | } while (0) |
| 82 | #else |
| 83 | #define avc_cache_stats_incr(field) do {} while (0) |
| 84 | #endif |
| 85 | |
| 86 | struct avc_entry { |
| 87 | u32 ssid; |
| 88 | u32 tsid; |
| 89 | u16 tclass; |
| 90 | struct av_decision avd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | }; |
| 92 | |
| 93 | struct avc_node { |
| 94 | struct avc_entry ae; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 95 | struct hlist_node list; /* anchored in avc_cache->slots[i] */ |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 96 | struct rcu_head rhead; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | }; |
| 98 | |
| 99 | struct avc_cache { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 100 | struct hlist_head slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */ |
| 102 | atomic_t lru_hint; /* LRU hint for reclaim scan */ |
| 103 | atomic_t active_nodes; |
| 104 | u32 latest_notif; /* latest revocation notification */ |
| 105 | }; |
| 106 | |
| 107 | struct avc_callback_node { |
| 108 | int (*callback) (u32 event, u32 ssid, u32 tsid, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 109 | u16 tclass, u32 perms, |
| 110 | u32 *out_retained); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | u32 events; |
| 112 | u32 ssid; |
| 113 | u32 tsid; |
| 114 | u16 tclass; |
| 115 | u32 perms; |
| 116 | struct avc_callback_node *next; |
| 117 | }; |
| 118 | |
| 119 | /* Exported via selinufs */ |
| 120 | unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD; |
| 121 | |
| 122 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS |
| 123 | DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 }; |
| 124 | #endif |
| 125 | |
| 126 | static struct avc_cache avc_cache; |
| 127 | static struct avc_callback_node *avc_callbacks; |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 128 | static struct kmem_cache *avc_node_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | |
| 130 | static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) |
| 131 | { |
| 132 | return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1); |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * avc_dump_av - Display an access vector in human-readable form. |
| 137 | * @tclass: target security class |
| 138 | * @av: access vector |
| 139 | */ |
KaiGai Kohei | 44c2d9b | 2009-06-18 17:26:13 +0900 | [diff] [blame] | 140 | 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] | 141 | { |
| 142 | const char **common_pts = NULL; |
| 143 | u32 common_base = 0; |
| 144 | int i, i2, perm; |
| 145 | |
| 146 | if (av == 0) { |
| 147 | audit_log_format(ab, " null"); |
| 148 | return; |
| 149 | } |
| 150 | |
| 151 | for (i = 0; i < ARRAY_SIZE(av_inherit); i++) { |
| 152 | if (av_inherit[i].tclass == tclass) { |
| 153 | common_pts = av_inherit[i].common_pts; |
| 154 | common_base = av_inherit[i].common_base; |
| 155 | break; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | audit_log_format(ab, " {"); |
| 160 | i = 0; |
| 161 | perm = 1; |
| 162 | while (perm < common_base) { |
| 163 | if (perm & av) { |
| 164 | audit_log_format(ab, " %s", common_pts[i]); |
| 165 | av &= ~perm; |
| 166 | } |
| 167 | i++; |
| 168 | perm <<= 1; |
| 169 | } |
| 170 | |
| 171 | while (i < sizeof(av) * 8) { |
| 172 | if (perm & av) { |
| 173 | for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) { |
| 174 | if ((av_perm_to_string[i2].tclass == tclass) && |
| 175 | (av_perm_to_string[i2].value == perm)) |
| 176 | break; |
| 177 | } |
| 178 | if (i2 < ARRAY_SIZE(av_perm_to_string)) { |
| 179 | audit_log_format(ab, " %s", |
| 180 | av_perm_to_string[i2].name); |
| 181 | av &= ~perm; |
| 182 | } |
| 183 | } |
| 184 | i++; |
| 185 | perm <<= 1; |
| 186 | } |
| 187 | |
| 188 | if (av) |
| 189 | audit_log_format(ab, " 0x%x", av); |
| 190 | |
| 191 | audit_log_format(ab, " }"); |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * avc_dump_query - Display a SID pair and a class in human-readable form. |
| 196 | * @ssid: source security identifier |
| 197 | * @tsid: target security identifier |
| 198 | * @tclass: target security class |
| 199 | */ |
| 200 | static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass) |
| 201 | { |
| 202 | int rc; |
| 203 | char *scontext; |
| 204 | u32 scontext_len; |
| 205 | |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 206 | rc = security_sid_to_context(ssid, &scontext, &scontext_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | if (rc) |
| 208 | audit_log_format(ab, "ssid=%d", ssid); |
| 209 | else { |
| 210 | audit_log_format(ab, "scontext=%s", scontext); |
| 211 | kfree(scontext); |
| 212 | } |
| 213 | |
| 214 | rc = security_sid_to_context(tsid, &scontext, &scontext_len); |
| 215 | if (rc) |
| 216 | audit_log_format(ab, " tsid=%d", tsid); |
| 217 | else { |
| 218 | audit_log_format(ab, " tcontext=%s", scontext); |
| 219 | kfree(scontext); |
| 220 | } |
Stephen Smalley | a764ae4 | 2007-03-26 13:36:26 -0400 | [diff] [blame] | 221 | |
| 222 | BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | audit_log_format(ab, " tclass=%s", class_to_string[tclass]); |
| 224 | } |
| 225 | |
| 226 | /** |
| 227 | * avc_init - Initialize the AVC. |
| 228 | * |
| 229 | * Initialize the access vector cache. |
| 230 | */ |
| 231 | void __init avc_init(void) |
| 232 | { |
| 233 | int i; |
| 234 | |
| 235 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 236 | INIT_HLIST_HEAD(&avc_cache.slots[i]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | spin_lock_init(&avc_cache.slots_lock[i]); |
| 238 | } |
| 239 | atomic_set(&avc_cache.active_nodes, 0); |
| 240 | atomic_set(&avc_cache.lru_hint, 0); |
| 241 | |
| 242 | avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node), |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 243 | 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | |
David Woodhouse | 9ad9ad3 | 2005-06-22 15:04:33 +0100 | [diff] [blame] | 245 | audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | } |
| 247 | |
| 248 | int avc_get_hash_stats(char *page) |
| 249 | { |
| 250 | int i, chain_len, max_chain_len, slots_used; |
| 251 | struct avc_node *node; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 252 | struct hlist_head *head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | |
| 254 | rcu_read_lock(); |
| 255 | |
| 256 | slots_used = 0; |
| 257 | max_chain_len = 0; |
| 258 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 259 | head = &avc_cache.slots[i]; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 260 | if (!hlist_empty(head)) { |
| 261 | struct hlist_node *next; |
| 262 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | slots_used++; |
| 264 | chain_len = 0; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 265 | hlist_for_each_entry_rcu(node, next, head, list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | chain_len++; |
| 267 | if (chain_len > max_chain_len) |
| 268 | max_chain_len = chain_len; |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | rcu_read_unlock(); |
| 273 | |
| 274 | return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n" |
| 275 | "longest chain: %d\n", |
| 276 | atomic_read(&avc_cache.active_nodes), |
| 277 | slots_used, AVC_CACHE_SLOTS, max_chain_len); |
| 278 | } |
| 279 | |
| 280 | static void avc_node_free(struct rcu_head *rhead) |
| 281 | { |
| 282 | struct avc_node *node = container_of(rhead, struct avc_node, rhead); |
| 283 | kmem_cache_free(avc_node_cachep, node); |
| 284 | avc_cache_stats_incr(frees); |
| 285 | } |
| 286 | |
| 287 | static void avc_node_delete(struct avc_node *node) |
| 288 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 289 | hlist_del_rcu(&node->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | call_rcu(&node->rhead, avc_node_free); |
| 291 | atomic_dec(&avc_cache.active_nodes); |
| 292 | } |
| 293 | |
| 294 | static void avc_node_kill(struct avc_node *node) |
| 295 | { |
| 296 | kmem_cache_free(avc_node_cachep, node); |
| 297 | avc_cache_stats_incr(frees); |
| 298 | atomic_dec(&avc_cache.active_nodes); |
| 299 | } |
| 300 | |
| 301 | static void avc_node_replace(struct avc_node *new, struct avc_node *old) |
| 302 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 303 | hlist_replace_rcu(&old->list, &new->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | call_rcu(&old->rhead, avc_node_free); |
| 305 | atomic_dec(&avc_cache.active_nodes); |
| 306 | } |
| 307 | |
| 308 | static inline int avc_reclaim_node(void) |
| 309 | { |
| 310 | struct avc_node *node; |
| 311 | int hvalue, try, ecx; |
| 312 | unsigned long flags; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 313 | struct hlist_head *head; |
| 314 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 315 | spinlock_t *lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 317 | for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 319 | head = &avc_cache.slots[hvalue]; |
| 320 | lock = &avc_cache.slots_lock[hvalue]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 322 | if (!spin_trylock_irqsave(lock, flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | continue; |
| 324 | |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 325 | rcu_read_lock(); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 326 | hlist_for_each_entry(node, next, head, list) { |
Eric Paris | 906d27d | 2009-02-12 14:50:43 -0500 | [diff] [blame] | 327 | avc_node_delete(node); |
| 328 | avc_cache_stats_incr(reclaims); |
| 329 | ecx++; |
| 330 | if (ecx >= AVC_CACHE_RECLAIM) { |
| 331 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 332 | spin_unlock_irqrestore(lock, flags); |
Eric Paris | 906d27d | 2009-02-12 14:50:43 -0500 | [diff] [blame] | 333 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | } |
| 335 | } |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 336 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 337 | spin_unlock_irqrestore(lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | } |
| 339 | out: |
| 340 | return ecx; |
| 341 | } |
| 342 | |
| 343 | static struct avc_node *avc_alloc_node(void) |
| 344 | { |
| 345 | struct avc_node *node; |
| 346 | |
Robert P. J. Day | c376222 | 2007-02-10 01:45:03 -0800 | [diff] [blame] | 347 | node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | if (!node) |
| 349 | goto out; |
| 350 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | INIT_RCU_HEAD(&node->rhead); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 352 | INIT_HLIST_NODE(&node->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | avc_cache_stats_incr(allocations); |
| 354 | |
| 355 | if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold) |
| 356 | avc_reclaim_node(); |
| 357 | |
| 358 | out: |
| 359 | return node; |
| 360 | } |
| 361 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 362 | 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] | 363 | { |
| 364 | node->ae.ssid = ssid; |
| 365 | node->ae.tsid = tsid; |
| 366 | node->ae.tclass = tclass; |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 367 | memcpy(&node->ae.avd, avd, sizeof(node->ae.avd)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | } |
| 369 | |
| 370 | static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass) |
| 371 | { |
| 372 | struct avc_node *node, *ret = NULL; |
| 373 | int hvalue; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 374 | struct hlist_head *head; |
| 375 | struct hlist_node *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | |
| 377 | hvalue = avc_hash(ssid, tsid, tclass); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 378 | head = &avc_cache.slots[hvalue]; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 379 | hlist_for_each_entry_rcu(node, next, head, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | if (ssid == node->ae.ssid && |
| 381 | tclass == node->ae.tclass && |
| 382 | tsid == node->ae.tsid) { |
| 383 | ret = node; |
| 384 | break; |
| 385 | } |
| 386 | } |
| 387 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | return ret; |
| 389 | } |
| 390 | |
| 391 | /** |
| 392 | * avc_lookup - Look up an AVC entry. |
| 393 | * @ssid: source security identifier |
| 394 | * @tsid: target security identifier |
| 395 | * @tclass: target security class |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | * |
| 397 | * Look up an AVC entry that is valid for the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | * (@ssid, @tsid), interpreting the permissions |
| 399 | * based on @tclass. If a valid AVC entry exists, |
| 400 | * then this function return the avc_node. |
| 401 | * Otherwise, this function returns NULL. |
| 402 | */ |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 403 | static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | { |
| 405 | struct avc_node *node; |
| 406 | |
| 407 | avc_cache_stats_incr(lookups); |
| 408 | node = avc_search_node(ssid, tsid, tclass); |
| 409 | |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 410 | if (node) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | avc_cache_stats_incr(hits); |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 412 | else |
| 413 | avc_cache_stats_incr(misses); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | return node; |
| 416 | } |
| 417 | |
| 418 | static int avc_latest_notif_update(int seqno, int is_insert) |
| 419 | { |
| 420 | int ret = 0; |
| 421 | static DEFINE_SPINLOCK(notif_lock); |
| 422 | unsigned long flag; |
| 423 | |
| 424 | spin_lock_irqsave(¬if_lock, flag); |
| 425 | if (is_insert) { |
| 426 | if (seqno < avc_cache.latest_notif) { |
Eric Paris | 744ba35 | 2008-04-17 11:52:44 -0400 | [diff] [blame] | 427 | printk(KERN_WARNING "SELinux: avc: seqno %d < latest_notif %d\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | seqno, avc_cache.latest_notif); |
| 429 | ret = -EAGAIN; |
| 430 | } |
| 431 | } else { |
| 432 | if (seqno > avc_cache.latest_notif) |
| 433 | avc_cache.latest_notif = seqno; |
| 434 | } |
| 435 | spin_unlock_irqrestore(¬if_lock, flag); |
| 436 | |
| 437 | return ret; |
| 438 | } |
| 439 | |
| 440 | /** |
| 441 | * avc_insert - Insert an AVC entry. |
| 442 | * @ssid: source security identifier |
| 443 | * @tsid: target security identifier |
| 444 | * @tclass: target security class |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 445 | * @avd: resulting av decision |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | * |
| 447 | * Insert an AVC entry for the SID pair |
| 448 | * (@ssid, @tsid) and class @tclass. |
| 449 | * The access vectors and the sequence number are |
| 450 | * normally provided by the security server in |
| 451 | * response to a security_compute_av() call. If the |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 452 | * sequence number @avd->seqno is not less than the latest |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | * revocation notification, then the function copies |
| 454 | * the access vectors into a cache entry, returns |
| 455 | * avc_node inserted. Otherwise, this function returns NULL. |
| 456 | */ |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 457 | 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] | 458 | { |
| 459 | struct avc_node *pos, *node = NULL; |
| 460 | int hvalue; |
| 461 | unsigned long flag; |
| 462 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 463 | if (avc_latest_notif_update(avd->seqno, 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | goto out; |
| 465 | |
| 466 | node = avc_alloc_node(); |
| 467 | if (node) { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 468 | struct hlist_head *head; |
| 469 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 470 | spinlock_t *lock; |
| 471 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | hvalue = avc_hash(ssid, tsid, tclass); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 473 | avc_node_populate(node, ssid, tsid, tclass, avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 475 | head = &avc_cache.slots[hvalue]; |
| 476 | lock = &avc_cache.slots_lock[hvalue]; |
| 477 | |
| 478 | spin_lock_irqsave(lock, flag); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 479 | hlist_for_each_entry(pos, next, head, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | if (pos->ae.ssid == ssid && |
| 481 | pos->ae.tsid == tsid && |
| 482 | pos->ae.tclass == tclass) { |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 483 | avc_node_replace(node, pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | goto found; |
| 485 | } |
| 486 | } |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 487 | hlist_add_head_rcu(&node->list, head); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | found: |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 489 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | } |
| 491 | out: |
| 492 | return node; |
| 493 | } |
| 494 | |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 495 | /** |
| 496 | * avc_audit_pre_callback - SELinux specific information |
| 497 | * will be called by generic audit code |
| 498 | * @ab: the audit buffer |
| 499 | * @a: audit_data |
| 500 | */ |
| 501 | static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 503 | struct common_audit_data *ad = a; |
| 504 | audit_log_format(ab, "avc: %s ", |
| 505 | ad->selinux_audit_data.denied ? "denied" : "granted"); |
| 506 | avc_dump_av(ab, ad->selinux_audit_data.tclass, |
| 507 | ad->selinux_audit_data.audited); |
| 508 | audit_log_format(ab, " for "); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | } |
| 510 | |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 511 | /** |
| 512 | * avc_audit_post_callback - SELinux specific information |
| 513 | * will be called by generic audit code |
| 514 | * @ab: the audit buffer |
| 515 | * @a: audit_data |
| 516 | */ |
| 517 | static void avc_audit_post_callback(struct audit_buffer *ab, void *a) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 519 | struct common_audit_data *ad = a; |
| 520 | audit_log_format(ab, " "); |
| 521 | avc_dump_query(ab, ad->selinux_audit_data.ssid, |
| 522 | ad->selinux_audit_data.tsid, |
| 523 | ad->selinux_audit_data.tclass); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | } |
| 525 | |
| 526 | /** |
| 527 | * avc_audit - Audit the granting or denial of permissions. |
| 528 | * @ssid: source security identifier |
| 529 | * @tsid: target security identifier |
| 530 | * @tclass: target security class |
| 531 | * @requested: requested permissions |
| 532 | * @avd: access vector decisions |
| 533 | * @result: result from avc_has_perm_noaudit |
| 534 | * @a: auxiliary audit data |
| 535 | * |
| 536 | * Audit the granting or denial of permissions in accordance |
| 537 | * with the policy. This function is typically called by |
| 538 | * avc_has_perm() after a permission check, but can also be |
| 539 | * called directly by callers who use avc_has_perm_noaudit() |
| 540 | * in order to separate the permission check from the auditing. |
| 541 | * For example, this separation is useful when the permission check must |
| 542 | * be performed under a lock, to allow the lock to be released |
| 543 | * before calling the auditing code. |
| 544 | */ |
| 545 | void avc_audit(u32 ssid, u32 tsid, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 546 | u16 tclass, u32 requested, |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 547 | struct av_decision *avd, int result, struct common_audit_data *a) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | { |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 549 | struct common_audit_data stack_data; |
James Morris | be940d6 | 2009-07-13 10:39:36 +1000 | [diff] [blame] | 550 | u32 denied, audited; |
James Morris | be940d6 | 2009-07-13 10:39:36 +1000 | [diff] [blame] | 551 | denied = requested & ~avd->allowed; |
| 552 | if (denied) { |
| 553 | audited = denied; |
| 554 | if (!(audited & avd->auditdeny)) |
| 555 | return; |
| 556 | } else if (result) { |
| 557 | audited = denied = requested; |
| 558 | } else { |
| 559 | audited = requested; |
| 560 | if (!(audited & avd->auditallow)) |
| 561 | return; |
| 562 | } |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 563 | if (!a) { |
| 564 | a = &stack_data; |
| 565 | memset(a, 0, sizeof(*a)); |
| 566 | a->type = LSM_AUDIT_NO_AUDIT; |
James Morris | be940d6 | 2009-07-13 10:39:36 +1000 | [diff] [blame] | 567 | } |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 568 | a->selinux_audit_data.tclass = tclass; |
| 569 | a->selinux_audit_data.requested = requested; |
| 570 | a->selinux_audit_data.ssid = ssid; |
| 571 | a->selinux_audit_data.tsid = tsid; |
| 572 | a->selinux_audit_data.audited = audited; |
| 573 | a->selinux_audit_data.denied = denied; |
| 574 | a->lsm_pre_audit = avc_audit_pre_callback; |
| 575 | a->lsm_post_audit = avc_audit_post_callback; |
| 576 | common_lsm_audit(a); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | } |
| 578 | |
| 579 | /** |
| 580 | * avc_add_callback - Register a callback for security events. |
| 581 | * @callback: callback function |
| 582 | * @events: security events |
| 583 | * @ssid: source security identifier or %SECSID_WILD |
| 584 | * @tsid: target security identifier or %SECSID_WILD |
| 585 | * @tclass: target security class |
| 586 | * @perms: permissions |
| 587 | * |
| 588 | * Register a callback function for events in the set @events |
| 589 | * related to the SID pair (@ssid, @tsid) and |
| 590 | * and the permissions @perms, interpreting |
| 591 | * @perms based on @tclass. Returns %0 on success or |
| 592 | * -%ENOMEM if insufficient memory exists to add the callback. |
| 593 | */ |
| 594 | int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 595 | u16 tclass, u32 perms, |
| 596 | u32 *out_retained), |
| 597 | u32 events, u32 ssid, u32 tsid, |
| 598 | u16 tclass, u32 perms) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | { |
| 600 | struct avc_callback_node *c; |
| 601 | int rc = 0; |
| 602 | |
| 603 | c = kmalloc(sizeof(*c), GFP_ATOMIC); |
| 604 | if (!c) { |
| 605 | rc = -ENOMEM; |
| 606 | goto out; |
| 607 | } |
| 608 | |
| 609 | c->callback = callback; |
| 610 | c->events = events; |
| 611 | c->ssid = ssid; |
| 612 | c->tsid = tsid; |
| 613 | c->perms = perms; |
| 614 | c->next = avc_callbacks; |
| 615 | avc_callbacks = c; |
| 616 | out: |
| 617 | return rc; |
| 618 | } |
| 619 | |
| 620 | static inline int avc_sidcmp(u32 x, u32 y) |
| 621 | { |
| 622 | return (x == y || x == SECSID_WILD || y == SECSID_WILD); |
| 623 | } |
| 624 | |
| 625 | /** |
| 626 | * avc_update_node Update an AVC entry |
| 627 | * @event : Updating event |
| 628 | * @perms : Permission mask bits |
| 629 | * @ssid,@tsid,@tclass : identifier of an AVC entry |
Eric Paris | a5dda683 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 630 | * @seqno : sequence number when decision was made |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | * |
| 632 | * if a valid AVC entry doesn't exist,this function returns -ENOENT. |
| 633 | * if kmalloc() called internal returns NULL, this function returns -ENOMEM. |
| 634 | * otherwise, this function update the AVC entry. The original AVC-entry object |
| 635 | * will release later by RCU. |
| 636 | */ |
Eric Paris | a5dda683 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 637 | static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, |
| 638 | u32 seqno) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | { |
| 640 | int hvalue, rc = 0; |
| 641 | unsigned long flag; |
| 642 | struct avc_node *pos, *node, *orig = NULL; |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 643 | struct hlist_head *head; |
| 644 | struct hlist_node *next; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 645 | spinlock_t *lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | |
| 647 | node = avc_alloc_node(); |
| 648 | if (!node) { |
| 649 | rc = -ENOMEM; |
| 650 | goto out; |
| 651 | } |
| 652 | |
| 653 | /* Lock the target slot */ |
| 654 | hvalue = avc_hash(ssid, tsid, tclass); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 656 | head = &avc_cache.slots[hvalue]; |
| 657 | lock = &avc_cache.slots_lock[hvalue]; |
| 658 | |
| 659 | spin_lock_irqsave(lock, flag); |
| 660 | |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 661 | hlist_for_each_entry(pos, next, head, list) { |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 662 | if (ssid == pos->ae.ssid && |
| 663 | tsid == pos->ae.tsid && |
Eric Paris | a5dda683 | 2009-02-12 14:50:11 -0500 | [diff] [blame] | 664 | tclass == pos->ae.tclass && |
| 665 | seqno == pos->ae.avd.seqno){ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | orig = pos; |
| 667 | break; |
| 668 | } |
| 669 | } |
| 670 | |
| 671 | if (!orig) { |
| 672 | rc = -ENOENT; |
| 673 | avc_node_kill(node); |
| 674 | goto out_unlock; |
| 675 | } |
| 676 | |
| 677 | /* |
| 678 | * Copy and replace original node. |
| 679 | */ |
| 680 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 681 | avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | |
| 683 | switch (event) { |
| 684 | case AVC_CALLBACK_GRANT: |
| 685 | node->ae.avd.allowed |= perms; |
| 686 | break; |
| 687 | case AVC_CALLBACK_TRY_REVOKE: |
| 688 | case AVC_CALLBACK_REVOKE: |
| 689 | node->ae.avd.allowed &= ~perms; |
| 690 | break; |
| 691 | case AVC_CALLBACK_AUDITALLOW_ENABLE: |
| 692 | node->ae.avd.auditallow |= perms; |
| 693 | break; |
| 694 | case AVC_CALLBACK_AUDITALLOW_DISABLE: |
| 695 | node->ae.avd.auditallow &= ~perms; |
| 696 | break; |
| 697 | case AVC_CALLBACK_AUDITDENY_ENABLE: |
| 698 | node->ae.avd.auditdeny |= perms; |
| 699 | break; |
| 700 | case AVC_CALLBACK_AUDITDENY_DISABLE: |
| 701 | node->ae.avd.auditdeny &= ~perms; |
| 702 | break; |
| 703 | } |
| 704 | avc_node_replace(node, orig); |
| 705 | out_unlock: |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 706 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | out: |
| 708 | return rc; |
| 709 | } |
| 710 | |
| 711 | /** |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 712 | * avc_flush - Flush the cache |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | */ |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 714 | static void avc_flush(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | { |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 716 | struct hlist_head *head; |
| 717 | struct hlist_node *next; |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 718 | struct avc_node *node; |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 719 | spinlock_t *lock; |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 720 | unsigned long flag; |
| 721 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 722 | |
| 723 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 724 | head = &avc_cache.slots[i]; |
| 725 | lock = &avc_cache.slots_lock[i]; |
| 726 | |
| 727 | spin_lock_irqsave(lock, flag); |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 728 | /* |
| 729 | * With preemptable RCU, the outer spinlock does not |
| 730 | * prevent RCU grace periods from ending. |
| 731 | */ |
| 732 | rcu_read_lock(); |
Eric Paris | 2603665 | 2009-02-12 14:51:04 -0500 | [diff] [blame] | 733 | hlist_for_each_entry(node, next, head, list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | avc_node_delete(node); |
Paul E. McKenney | 6184425 | 2008-04-21 18:12:33 -0700 | [diff] [blame] | 735 | rcu_read_unlock(); |
Eric Paris | edf3d1a | 2009-02-12 14:50:59 -0500 | [diff] [blame] | 736 | spin_unlock_irqrestore(lock, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 737 | } |
Eric Paris | 008574b | 2009-09-12 22:54:17 -0400 | [diff] [blame] | 738 | } |
| 739 | |
| 740 | /** |
| 741 | * avc_ss_reset - Flush the cache and revalidate migrated permissions. |
| 742 | * @seqno: policy sequence number |
| 743 | */ |
| 744 | int avc_ss_reset(u32 seqno) |
| 745 | { |
| 746 | struct avc_callback_node *c; |
| 747 | int rc = 0, tmprc; |
| 748 | |
| 749 | avc_flush(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | |
| 751 | for (c = avc_callbacks; c; c = c->next) { |
| 752 | if (c->events & AVC_CALLBACK_RESET) { |
Darrel Goeddel | 376bd9c | 2006-02-24 15:44:05 -0600 | [diff] [blame] | 753 | tmprc = c->callback(AVC_CALLBACK_RESET, |
Eric Paris | 95fff33 | 2008-04-17 14:42:10 -0400 | [diff] [blame] | 754 | 0, 0, 0, 0, NULL); |
Darrel Goeddel | 376bd9c | 2006-02-24 15:44:05 -0600 | [diff] [blame] | 755 | /* save the first error encountered for the return |
| 756 | value and continue processing the callbacks */ |
| 757 | if (!rc) |
| 758 | rc = tmprc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | } |
| 760 | } |
| 761 | |
| 762 | avc_latest_notif_update(seqno, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 763 | return rc; |
| 764 | } |
| 765 | |
| 766 | /** |
| 767 | * avc_has_perm_noaudit - Check permissions but perform no auditing. |
| 768 | * @ssid: source security identifier |
| 769 | * @tsid: target security identifier |
| 770 | * @tclass: target security class |
| 771 | * @requested: requested permissions, interpreted based on @tclass |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 772 | * @flags: AVC_STRICT or 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | * @avd: access vector decisions |
| 774 | * |
| 775 | * Check the AVC to determine whether the @requested permissions are granted |
| 776 | * for the SID pair (@ssid, @tsid), interpreting the permissions |
| 777 | * based on @tclass, and call the security server on a cache miss to obtain |
| 778 | * a new decision and add it to the cache. Return a copy of the decisions |
| 779 | * in @avd. Return %0 if all @requested permissions are granted, |
| 780 | * -%EACCES if any permissions are denied, or another -errno upon |
| 781 | * other errors. This function is typically called by avc_has_perm(), |
| 782 | * but may also be called directly to separate permission checking from |
| 783 | * auditing, e.g. in cases where a lock must be held for the check but |
| 784 | * should be released for the auditing. |
| 785 | */ |
| 786 | int avc_has_perm_noaudit(u32 ssid, u32 tsid, |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 787 | u16 tclass, u32 requested, |
| 788 | unsigned flags, |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 789 | struct av_decision *in_avd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | { |
| 791 | struct avc_node *node; |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 792 | struct av_decision avd_entry, *avd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | int rc = 0; |
| 794 | u32 denied; |
| 795 | |
Eric Paris | eda4f69 | 2008-03-11 14:19:34 -0400 | [diff] [blame] | 796 | BUG_ON(!requested); |
| 797 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | rcu_read_lock(); |
| 799 | |
Eric Paris | f1c6381 | 2009-02-12 14:50:54 -0500 | [diff] [blame] | 800 | node = avc_lookup(ssid, tsid, tclass); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | if (!node) { |
| 802 | rcu_read_unlock(); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 803 | |
| 804 | if (in_avd) |
| 805 | avd = in_avd; |
| 806 | else |
| 807 | avd = &avd_entry; |
| 808 | |
| 809 | rc = security_compute_av(ssid, tsid, tclass, requested, avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | if (rc) |
| 811 | goto out; |
| 812 | rcu_read_lock(); |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 813 | node = avc_insert(ssid, tsid, tclass, avd); |
| 814 | } else { |
| 815 | if (in_avd) |
| 816 | memcpy(in_avd, &node->ae.avd, sizeof(*in_avd)); |
| 817 | avd = &node->ae.avd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 818 | } |
| 819 | |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 820 | denied = requested & ~(avd->allowed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | |
Eric Paris | eda4f69 | 2008-03-11 14:19:34 -0400 | [diff] [blame] | 822 | if (denied) { |
Eric Paris | 64dbf07 | 2008-03-31 12:17:33 +1100 | [diff] [blame] | 823 | if (flags & AVC_STRICT) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 824 | rc = -EACCES; |
KaiGai Kohei | 8a6f83a | 2009-04-01 10:07:57 +0900 | [diff] [blame] | 825 | else if (!selinux_enforcing || (avd->flags & AVD_FLAGS_PERMISSIVE)) |
Eric Paris | 64dbf07 | 2008-03-31 12:17:33 +1100 | [diff] [blame] | 826 | avc_update_node(AVC_CALLBACK_GRANT, requested, ssid, |
Eric Paris | 21193dc | 2009-02-12 14:50:49 -0500 | [diff] [blame] | 827 | tsid, tclass, avd->seqno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | else |
Eric Paris | 64dbf07 | 2008-03-31 12:17:33 +1100 | [diff] [blame] | 829 | rc = -EACCES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | } |
| 831 | |
| 832 | rcu_read_unlock(); |
| 833 | out: |
| 834 | return rc; |
| 835 | } |
| 836 | |
| 837 | /** |
| 838 | * avc_has_perm - Check permissions and perform any appropriate auditing. |
| 839 | * @ssid: source security identifier |
| 840 | * @tsid: target security identifier |
| 841 | * @tclass: target security class |
| 842 | * @requested: requested permissions, interpreted based on @tclass |
| 843 | * @auditdata: auxiliary audit data |
| 844 | * |
| 845 | * Check the AVC to determine whether the @requested permissions are granted |
| 846 | * for the SID pair (@ssid, @tsid), interpreting the permissions |
| 847 | * based on @tclass, and call the security server on a cache miss to obtain |
| 848 | * a new decision and add it to the cache. Audit the granting or denial of |
| 849 | * permissions in accordance with the policy. Return %0 if all @requested |
| 850 | * permissions are granted, -%EACCES if any permissions are denied, or |
| 851 | * another -errno upon other errors. |
| 852 | */ |
| 853 | int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, |
Thomas Liu | 2bf4969 | 2009-07-14 12:14:09 -0400 | [diff] [blame] | 854 | u32 requested, struct common_audit_data *auditdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 855 | { |
| 856 | struct av_decision avd; |
| 857 | int rc; |
| 858 | |
Stephen Smalley | 2c3c05d | 2007-06-07 15:34:10 -0400 | [diff] [blame] | 859 | rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata); |
| 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 | } |