2 * Implementation of the SID table type.
4 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
6 #include <linux/kernel.h>
7 #include <linux/slab.h>
8 #include <linux/spinlock.h>
9 #include <linux/errno.h>
14 #define SIDTAB_HASH(sid) \
15 (sid & SIDTAB_HASH_MASK)
17 int sidtab_init(struct sidtab *s)
21 s->htable = kmalloc_array(SIDTAB_SIZE, sizeof(*s->htable), GFP_ATOMIC);
24 for (i = 0; i < SIDTAB_SIZE; i++)
29 spin_lock_init(&s->lock);
33 int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
36 struct sidtab_node *prev, *cur, *newnode;
41 hvalue = SIDTAB_HASH(sid);
43 cur = s->htable[hvalue];
44 while (cur && sid > cur->sid) {
49 if (cur && sid == cur->sid)
52 newnode = kmalloc(sizeof(*newnode), GFP_ATOMIC);
57 if (context_cpy(&newnode->context, context)) {
63 newnode->next = prev->next;
67 newnode->next = s->htable[hvalue];
69 s->htable[hvalue] = newnode;
73 if (sid >= s->next_sid)
74 s->next_sid = sid + 1;
78 static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
81 struct sidtab_node *cur;
86 hvalue = SIDTAB_HASH(sid);
87 cur = s->htable[hvalue];
88 while (cur && sid > cur->sid)
91 if (force && cur && sid == cur->sid && cur->context.len)
94 if (!cur || sid != cur->sid || cur->context.len) {
95 /* Remap invalid SIDs to the unlabeled SID. */
96 sid = SECINITSID_UNLABELED;
97 hvalue = SIDTAB_HASH(sid);
98 cur = s->htable[hvalue];
99 while (cur && sid > cur->sid)
101 if (!cur || sid != cur->sid)
105 return &cur->context;
108 struct context *sidtab_search(struct sidtab *s, u32 sid)
110 return sidtab_search_core(s, sid, 0);
113 struct context *sidtab_search_force(struct sidtab *s, u32 sid)
115 return sidtab_search_core(s, sid, 1);
118 int sidtab_map(struct sidtab *s,
119 int (*apply) (u32 sid,
120 struct context *context,
125 struct sidtab_node *cur;
130 for (i = 0; i < SIDTAB_SIZE; i++) {
133 rc = apply(cur->sid, &cur->context, args);
143 static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc)
145 BUG_ON(loc >= SIDTAB_CACHE_LEN);
148 s->cache[loc] = s->cache[loc - 1];
154 static inline u32 sidtab_search_context(struct sidtab *s,
155 struct context *context)
158 struct sidtab_node *cur;
160 for (i = 0; i < SIDTAB_SIZE; i++) {
163 if (context_cmp(&cur->context, context)) {
164 sidtab_update_cache(s, cur, SIDTAB_CACHE_LEN - 1);
173 static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)
176 struct sidtab_node *node;
178 for (i = 0; i < SIDTAB_CACHE_LEN; i++) {
182 if (context_cmp(&node->context, context)) {
183 sidtab_update_cache(s, node, i);
190 int sidtab_context_to_sid(struct sidtab *s,
191 struct context *context,
198 *out_sid = SECSID_NULL;
200 sid = sidtab_search_cache(s, context);
202 sid = sidtab_search_context(s, context);
204 spin_lock_irqsave(&s->lock, flags);
205 /* Rescan now that we hold the lock. */
206 sid = sidtab_search_context(s, context);
209 /* No SID exists for the context. Allocate a new one. */
210 if (s->next_sid == UINT_MAX || s->shutdown) {
217 "SELinux: Context %s is not valid (left unmapped).\n",
219 ret = sidtab_insert(s, sid, context);
223 spin_unlock_irqrestore(&s->lock, flags);
233 void sidtab_hash_eval(struct sidtab *h, char *tag)
235 int i, chain_len, slots_used, max_chain_len;
236 struct sidtab_node *cur;
240 for (i = 0; i < SIDTAB_SIZE; i++) {
250 if (chain_len > max_chain_len)
251 max_chain_len = chain_len;
255 printk(KERN_DEBUG "%s: %d entries and %d/%d buckets used, longest "
256 "chain length %d\n", tag, h->nel, slots_used, SIDTAB_SIZE,
260 void sidtab_destroy(struct sidtab *s)
263 struct sidtab_node *cur, *temp;
268 for (i = 0; i < SIDTAB_SIZE; i++) {
273 context_destroy(&temp->context);
284 void sidtab_set(struct sidtab *dst, struct sidtab *src)
289 spin_lock_irqsave(&src->lock, flags);
290 dst->htable = src->htable;
292 dst->next_sid = src->next_sid;
294 for (i = 0; i < SIDTAB_CACHE_LEN; i++)
295 dst->cache[i] = NULL;
296 spin_unlock_irqrestore(&src->lock, flags);
299 void sidtab_shutdown(struct sidtab *s)
303 spin_lock_irqsave(&s->lock, flags);
305 spin_unlock_irqrestore(&s->lock, flags);