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6#include <linux/kernel.h>
7#include <linux/slab.h>
8#include <linux/spinlock.h>
9#include <linux/errno.h>
10#include "flask.h"
11#include "security.h"
12#include "sidtab.h"
13
14#define SIDTAB_HASH(sid) \
15(sid & SIDTAB_HASH_MASK)
16
17int sidtab_init(struct sidtab *s)
18{
19 int i;
20
21 s->htable = kmalloc(sizeof(*(s->htable)) * SIDTAB_SIZE, GFP_ATOMIC);
22 if (!s->htable)
23 return -ENOMEM;
24 for (i = 0; i < SIDTAB_SIZE; i++)
25 s->htable[i] = NULL;
26 s->nel = 0;
27 s->next_sid = 1;
28 s->shutdown = 0;
29 spin_lock_init(&s->lock);
30 return 0;
31}
32
33int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
34{
35 int hvalue, rc = 0;
36 struct sidtab_node *prev, *cur, *newnode;
37
38 if (!s) {
39 rc = -ENOMEM;
40 goto out;
41 }
42
43 hvalue = SIDTAB_HASH(sid);
44 prev = NULL;
45 cur = s->htable[hvalue];
46 while (cur && sid > cur->sid) {
47 prev = cur;
48 cur = cur->next;
49 }
50
51 if (cur && sid == cur->sid) {
52 rc = -EEXIST;
53 goto out;
54 }
55
56 newnode = kmalloc(sizeof(*newnode), GFP_ATOMIC);
57 if (newnode == NULL) {
58 rc = -ENOMEM;
59 goto out;
60 }
61 newnode->sid = sid;
62 if (context_cpy(&newnode->context, context)) {
63 kfree(newnode);
64 rc = -ENOMEM;
65 goto out;
66 }
67
68 if (prev) {
69 newnode->next = prev->next;
70 wmb();
71 prev->next = newnode;
72 } else {
73 newnode->next = s->htable[hvalue];
74 wmb();
75 s->htable[hvalue] = newnode;
76 }
77
78 s->nel++;
79 if (sid >= s->next_sid)
80 s->next_sid = sid + 1;
81out:
82 return rc;
83}
84
85static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
86{
87 int hvalue;
88 struct sidtab_node *cur;
89
90 if (!s)
91 return NULL;
92
93 hvalue = SIDTAB_HASH(sid);
94 cur = s->htable[hvalue];
95 while (cur && sid > cur->sid)
96 cur = cur->next;
97
98 if (force && cur && sid == cur->sid && cur->context.len)
99 return &cur->context;
100
101 if (cur == NULL || sid != cur->sid || cur->context.len) {
102
103 sid = SECINITSID_UNLABELED;
104 hvalue = SIDTAB_HASH(sid);
105 cur = s->htable[hvalue];
106 while (cur && sid > cur->sid)
107 cur = cur->next;
108 if (!cur || sid != cur->sid)
109 return NULL;
110 }
111
112 return &cur->context;
113}
114
115struct context *sidtab_search(struct sidtab *s, u32 sid)
116{
117 return sidtab_search_core(s, sid, 0);
118}
119
120struct context *sidtab_search_force(struct sidtab *s, u32 sid)
121{
122 return sidtab_search_core(s, sid, 1);
123}
124
125int sidtab_map(struct sidtab *s,
126 int (*apply) (u32 sid,
127 struct context *context,
128 void *args),
129 void *args)
130{
131 int i, rc = 0;
132 struct sidtab_node *cur;
133
134 if (!s)
135 goto out;
136
137 for (i = 0; i < SIDTAB_SIZE; i++) {
138 cur = s->htable[i];
139 while (cur) {
140 rc = apply(cur->sid, &cur->context, args);
141 if (rc)
142 goto out;
143 cur = cur->next;
144 }
145 }
146out:
147 return rc;
148}
149
150static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc)
151{
152 BUG_ON(loc >= SIDTAB_CACHE_LEN);
153
154 while (loc > 0) {
155 s->cache[loc] = s->cache[loc - 1];
156 loc--;
157 }
158 s->cache[0] = n;
159}
160
161static inline u32 sidtab_search_context(struct sidtab *s,
162 struct context *context)
163{
164 int i;
165 struct sidtab_node *cur;
166
167 for (i = 0; i < SIDTAB_SIZE; i++) {
168 cur = s->htable[i];
169 while (cur) {
170 if (context_cmp(&cur->context, context)) {
171 sidtab_update_cache(s, cur, SIDTAB_CACHE_LEN - 1);
172 return cur->sid;
173 }
174 cur = cur->next;
175 }
176 }
177 return 0;
178}
179
180static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)
181{
182 int i;
183 struct sidtab_node *node;
184
185 for (i = 0; i < SIDTAB_CACHE_LEN; i++) {
186 node = s->cache[i];
187 if (unlikely(!node))
188 return 0;
189 if (context_cmp(&node->context, context)) {
190 sidtab_update_cache(s, node, i);
191 return node->sid;
192 }
193 }
194 return 0;
195}
196
197int sidtab_context_to_sid(struct sidtab *s,
198 struct context *context,
199 u32 *out_sid)
200{
201 u32 sid;
202 int ret = 0;
203 unsigned long flags;
204
205 *out_sid = SECSID_NULL;
206
207 sid = sidtab_search_cache(s, context);
208 if (!sid)
209 sid = sidtab_search_context(s, context);
210 if (!sid) {
211 spin_lock_irqsave(&s->lock, flags);
212
213 sid = sidtab_search_context(s, context);
214 if (sid)
215 goto unlock_out;
216
217 if (s->next_sid == UINT_MAX || s->shutdown) {
218 ret = -ENOMEM;
219 goto unlock_out;
220 }
221 sid = s->next_sid++;
222 if (context->len)
223 printk(KERN_INFO
224 "SELinux: Context %s is not valid (left unmapped).\n",
225 context->str);
226 ret = sidtab_insert(s, sid, context);
227 if (ret)
228 s->next_sid--;
229unlock_out:
230 spin_unlock_irqrestore(&s->lock, flags);
231 }
232
233 if (ret)
234 return ret;
235
236 *out_sid = sid;
237 return 0;
238}
239
240void sidtab_hash_eval(struct sidtab *h, char *tag)
241{
242 int i, chain_len, slots_used, max_chain_len;
243 struct sidtab_node *cur;
244
245 slots_used = 0;
246 max_chain_len = 0;
247 for (i = 0; i < SIDTAB_SIZE; i++) {
248 cur = h->htable[i];
249 if (cur) {
250 slots_used++;
251 chain_len = 0;
252 while (cur) {
253 chain_len++;
254 cur = cur->next;
255 }
256
257 if (chain_len > max_chain_len)
258 max_chain_len = chain_len;
259 }
260 }
261
262 printk(KERN_DEBUG "%s: %d entries and %d/%d buckets used, longest "
263 "chain length %d\n", tag, h->nel, slots_used, SIDTAB_SIZE,
264 max_chain_len);
265}
266
267void sidtab_destroy(struct sidtab *s)
268{
269 int i;
270 struct sidtab_node *cur, *temp;
271
272 if (!s)
273 return;
274
275 for (i = 0; i < SIDTAB_SIZE; i++) {
276 cur = s->htable[i];
277 while (cur) {
278 temp = cur;
279 cur = cur->next;
280 context_destroy(&temp->context);
281 kfree(temp);
282 }
283 s->htable[i] = NULL;
284 }
285 kfree(s->htable);
286 s->htable = NULL;
287 s->nel = 0;
288 s->next_sid = 1;
289}
290
291void sidtab_set(struct sidtab *dst, struct sidtab *src)
292{
293 unsigned long flags;
294 int i;
295
296 spin_lock_irqsave(&src->lock, flags);
297 dst->htable = src->htable;
298 dst->nel = src->nel;
299 dst->next_sid = src->next_sid;
300 dst->shutdown = 0;
301 for (i = 0; i < SIDTAB_CACHE_LEN; i++)
302 dst->cache[i] = NULL;
303 spin_unlock_irqrestore(&src->lock, flags);
304}
305
306void sidtab_shutdown(struct sidtab *s)
307{
308 unsigned long flags;
309
310 spin_lock_irqsave(&s->lock, flags);
311 s->shutdown = 1;
312 spin_unlock_irqrestore(&s->lock, flags);
313}
314
