d8ce9cc0b9f15042c50bc7abf2b3bea9202031bb
[linux-3.10.git] / security / selinux / ss / ebitmap.c
1 /*
2  * Implementation of the extensible bitmap type.
3  *
4  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
5  */
6 #include <linux/kernel.h>
7 #include <linux/slab.h>
8 #include <linux/errno.h>
9 #include "ebitmap.h"
10 #include "policydb.h"
11
12 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
13 {
14         struct ebitmap_node *n1, *n2;
15
16         if (e1->highbit != e2->highbit)
17                 return 0;
18
19         n1 = e1->node;
20         n2 = e2->node;
21         while (n1 && n2 &&
22                (n1->startbit == n2->startbit) &&
23                (n1->map == n2->map)) {
24                 n1 = n1->next;
25                 n2 = n2->next;
26         }
27
28         if (n1 || n2)
29                 return 0;
30
31         return 1;
32 }
33
34 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src)
35 {
36         struct ebitmap_node *n, *new, *prev;
37
38         ebitmap_init(dst);
39         n = src->node;
40         prev = NULL;
41         while (n) {
42                 new = kmalloc(sizeof(*new), GFP_ATOMIC);
43                 if (!new) {
44                         ebitmap_destroy(dst);
45                         return -ENOMEM;
46                 }
47                 memset(new, 0, sizeof(*new));
48                 new->startbit = n->startbit;
49                 new->map = n->map;
50                 new->next = NULL;
51                 if (prev)
52                         prev->next = new;
53                 else
54                         dst->node = new;
55                 prev = new;
56                 n = n->next;
57         }
58
59         dst->highbit = src->highbit;
60         return 0;
61 }
62
63 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2)
64 {
65         struct ebitmap_node *n1, *n2;
66
67         if (e1->highbit < e2->highbit)
68                 return 0;
69
70         n1 = e1->node;
71         n2 = e2->node;
72         while (n1 && n2 && (n1->startbit <= n2->startbit)) {
73                 if (n1->startbit < n2->startbit) {
74                         n1 = n1->next;
75                         continue;
76                 }
77                 if ((n1->map & n2->map) != n2->map)
78                         return 0;
79
80                 n1 = n1->next;
81                 n2 = n2->next;
82         }
83
84         if (n2)
85                 return 0;
86
87         return 1;
88 }
89
90 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
91 {
92         struct ebitmap_node *n;
93
94         if (e->highbit < bit)
95                 return 0;
96
97         n = e->node;
98         while (n && (n->startbit <= bit)) {
99                 if ((n->startbit + MAPSIZE) > bit) {
100                         if (n->map & (MAPBIT << (bit - n->startbit)))
101                                 return 1;
102                         else
103                                 return 0;
104                 }
105                 n = n->next;
106         }
107
108         return 0;
109 }
110
111 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
112 {
113         struct ebitmap_node *n, *prev, *new;
114
115         prev = NULL;
116         n = e->node;
117         while (n && n->startbit <= bit) {
118                 if ((n->startbit + MAPSIZE) > bit) {
119                         if (value) {
120                                 n->map |= (MAPBIT << (bit - n->startbit));
121                         } else {
122                                 n->map &= ~(MAPBIT << (bit - n->startbit));
123                                 if (!n->map) {
124                                         /* drop this node from the bitmap */
125
126                                         if (!n->next) {
127                                                 /*
128                                                  * this was the highest map
129                                                  * within the bitmap
130                                                  */
131                                                 if (prev)
132                                                         e->highbit = prev->startbit + MAPSIZE;
133                                                 else
134                                                         e->highbit = 0;
135                                         }
136                                         if (prev)
137                                                 prev->next = n->next;
138                                         else
139                                                 e->node = n->next;
140
141                                         kfree(n);
142                                 }
143                         }
144                         return 0;
145                 }
146                 prev = n;
147                 n = n->next;
148         }
149
150         if (!value)
151                 return 0;
152
153         new = kmalloc(sizeof(*new), GFP_ATOMIC);
154         if (!new)
155                 return -ENOMEM;
156         memset(new, 0, sizeof(*new));
157
158         new->startbit = bit & ~(MAPSIZE - 1);
159         new->map = (MAPBIT << (bit - new->startbit));
160
161         if (!n)
162                 /* this node will be the highest map within the bitmap */
163                 e->highbit = new->startbit + MAPSIZE;
164
165         if (prev) {
166                 new->next = prev->next;
167                 prev->next = new;
168         } else {
169                 new->next = e->node;
170                 e->node = new;
171         }
172
173         return 0;
174 }
175
176 void ebitmap_destroy(struct ebitmap *e)
177 {
178         struct ebitmap_node *n, *temp;
179
180         if (!e)
181                 return;
182
183         n = e->node;
184         while (n) {
185                 temp = n;
186                 n = n->next;
187                 kfree(temp);
188         }
189
190         e->highbit = 0;
191         e->node = NULL;
192         return;
193 }
194
195 int ebitmap_read(struct ebitmap *e, void *fp)
196 {
197         int rc;
198         struct ebitmap_node *n, *l;
199         u32 buf[3], mapsize, count, i;
200         u64 map;
201
202         ebitmap_init(e);
203
204         rc = next_entry(buf, fp, sizeof buf);
205         if (rc < 0)
206                 goto out;
207
208         mapsize = le32_to_cpu(buf[0]);
209         e->highbit = le32_to_cpu(buf[1]);
210         count = le32_to_cpu(buf[2]);
211
212         if (mapsize != MAPSIZE) {
213                 printk(KERN_ERR "security: ebitmap: map size %u does not "
214                        "match my size %Zd (high bit was %d)\n", mapsize,
215                        MAPSIZE, e->highbit);
216                 goto bad;
217         }
218         if (!e->highbit) {
219                 e->node = NULL;
220                 goto ok;
221         }
222         if (e->highbit & (MAPSIZE - 1)) {
223                 printk(KERN_ERR "security: ebitmap: high bit (%d) is not a "
224                        "multiple of the map size (%Zd)\n", e->highbit, MAPSIZE);
225                 goto bad;
226         }
227         l = NULL;
228         for (i = 0; i < count; i++) {
229                 rc = next_entry(buf, fp, sizeof(u32));
230                 if (rc < 0) {
231                         printk(KERN_ERR "security: ebitmap: truncated map\n");
232                         goto bad;
233                 }
234                 n = kmalloc(sizeof(*n), GFP_KERNEL);
235                 if (!n) {
236                         printk(KERN_ERR "security: ebitmap: out of memory\n");
237                         rc = -ENOMEM;
238                         goto bad;
239                 }
240                 memset(n, 0, sizeof(*n));
241
242                 n->startbit = le32_to_cpu(buf[0]);
243
244                 if (n->startbit & (MAPSIZE - 1)) {
245                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
246                                "not a multiple of the map size (%Zd)\n",
247                                n->startbit, MAPSIZE);
248                         goto bad_free;
249                 }
250                 if (n->startbit > (e->highbit - MAPSIZE)) {
251                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
252                                "beyond the end of the bitmap (%Zd)\n",
253                                n->startbit, (e->highbit - MAPSIZE));
254                         goto bad_free;
255                 }
256                 rc = next_entry(&map, fp, sizeof(u64));
257                 if (rc < 0) {
258                         printk(KERN_ERR "security: ebitmap: truncated map\n");
259                         goto bad_free;
260                 }
261                 n->map = le64_to_cpu(map);
262
263                 if (!n->map) {
264                         printk(KERN_ERR "security: ebitmap: null map in "
265                                "ebitmap (startbit %d)\n", n->startbit);
266                         goto bad_free;
267                 }
268                 if (l) {
269                         if (n->startbit <= l->startbit) {
270                                 printk(KERN_ERR "security: ebitmap: start "
271                                        "bit %d comes after start bit %d\n",
272                                        n->startbit, l->startbit);
273                                 goto bad_free;
274                         }
275                         l->next = n;
276                 } else
277                         e->node = n;
278
279                 l = n;
280         }
281
282 ok:
283         rc = 0;
284 out:
285         return rc;
286 bad_free:
287         kfree(n);
288 bad:
289         if (!rc)
290                 rc = -EINVAL;
291         ebitmap_destroy(e);
292         goto out;
293 }