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 = kzalloc(sizeof(*new), GFP_ATOMIC);
  43                 if (!new) {
  44                         ebitmap_destroy(dst);
  45                         return -ENOMEM;
  46                 }
  47                 new->startbit = n->startbit;
  48                 new->map = n->map;
  49                 new->next = NULL;
  50                 if (prev)
  51                         prev->next = new;
  52                 else
  53                         dst->node = new;
  54                 prev = new;
  55                 n = n->next;
  56         }
  57
  58         dst->highbit = src->highbit;
  59         return 0;
  60 }
  61
  62 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2)
  63 {
  64         struct ebitmap_node *n1, *n2;
  65
  66         if (e1->highbit < e2->highbit)
  67                 return 0;
  68
  69         n1 = e1->node;
  70         n2 = e2->node;
  71         while (n1 && n2 && (n1->startbit <= n2->startbit)) {
  72                 if (n1->startbit < n2->startbit) {
  73                         n1 = n1->next;
  74                         continue;
  75                 }
  76                 if ((n1->map & n2->map) != n2->map)
  77                         return 0;
  78
  79                 n1 = n1->next;
  80                 n2 = n2->next;
  81         }
  82
  83         if (n2)
  84                 return 0;
  85
  86         return 1;
  87 }
  88
  89 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
  90 {
  91         struct ebitmap_node *n;
  92
  93         if (e->highbit < bit)
  94                 return 0;
  95
  96         n = e->node;
  97         while (n && (n->startbit <= bit)) {
  98                 if ((n->startbit + MAPSIZE) > bit) {
  99                         if (n->map & (MAPBIT << (bit - n->startbit)))
 100                                 return 1;
 101                         else
 102                                 return 0;
 103                 }
 104                 n = n->next;
 105         }
 106
 107         return 0;
 108 }
 109
 110 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
 111 {
 112         struct ebitmap_node *n, *prev, *new;
 113
 114         prev = NULL;
 115         n = e->node;
 116         while (n && n->startbit <= bit) {
 117                 if ((n->startbit + MAPSIZE) > bit) {
 118                         if (value) {
 119                                 n->map |= (MAPBIT << (bit - n->startbit));
 120                         } else {
 121                                 n->map &= ~(MAPBIT << (bit - n->startbit));
 122                                 if (!n->map) {
 123                                         /* drop this node from the bitmap */
 124
 125                                         if (!n->next) {
 126                                                 /*
 127                                                  * this was the highest map
 128                                                  * within the bitmap
 129                                                  */
 130                                                 if (prev)
 131                                                         e->highbit = prev->startbit + MAPSIZE;
 132                                                 else
 133                                                         e->highbit = 0;
 134                                         }
 135                                         if (prev)
 136                                                 prev->next = n->next;
 137                                         else
 138                                                 e->node = n->next;
 139
 140                                         kfree(n);
 141                                 }
 142                         }
 143                         return 0;
 144                 }
 145                 prev = n;
 146                 n = n->next;
 147         }
 148
 149         if (!value)
 150                 return 0;
 151
 152         new = kzalloc(sizeof(*new), GFP_ATOMIC);
 153         if (!new)
 154                 return -ENOMEM;
 155
 156         new->startbit = bit & ~(MAPSIZE - 1);
 157         new->map = (MAPBIT << (bit - new->startbit));
 158
 159         if (!n)
 160                 /* this node will be the highest map within the bitmap */
 161                 e->highbit = new->startbit + MAPSIZE;
 162
 163         if (prev) {
 164                 new->next = prev->next;
 165                 prev->next = new;
 166         } else {
 167                 new->next = e->node;
 168                 e->node = new;
 169         }
 170
 171         return 0;
 172 }
 173
 174 void ebitmap_destroy(struct ebitmap *e)
 175 {
 176         struct ebitmap_node *n, *temp;
 177
 178         if (!e)
 179                 return;
 180
 181         n = e->node;
 182         while (n) {
 183                 temp = n;
 184                 n = n->next;
 185                 kfree(temp);
 186         }
 187
 188         e->highbit = 0;
 189         e->node = NULL;
 190         return;
 191 }
 192
 193 int ebitmap_read(struct ebitmap *e, void *fp)
 194 {
 195         int rc;
 196         struct ebitmap_node *n, *l;
 197         __le32 buf[3];
 198         u32 mapsize, count, i;
 199         __le64 map;
 200
 201         ebitmap_init(e);
 202
 203         rc = next_entry(buf, fp, sizeof buf);
 204         if (rc < 0)
 205                 goto out;
 206
 207         mapsize = le32_to_cpu(buf[0]);
 208         e->highbit = le32_to_cpu(buf[1]);
 209         count = le32_to_cpu(buf[2]);
 210
 211         if (mapsize != MAPSIZE) {
 212                 printk(KERN_ERR "security: ebitmap: map size %u does not "
 213                        "match my size %Zd (high bit was %d)\n", mapsize,
 214                        MAPSIZE, e->highbit);
 215                 goto bad;
 216         }
 217         if (!e->highbit) {
 218                 e->node = NULL;
 219                 goto ok;
 220         }
 221         if (e->highbit & (MAPSIZE - 1)) {
 222                 printk(KERN_ERR "security: ebitmap: high bit (%d) is not a "
 223                        "multiple of the map size (%Zd)\n", e->highbit, MAPSIZE);
 224                 goto bad;
 225         }
 226         l = NULL;
 227         for (i = 0; i < count; i++) {
 228                 rc = next_entry(buf, fp, sizeof(u32));
 229                 if (rc < 0) {
 230                         printk(KERN_ERR "security: ebitmap: truncated map\n");
 231                         goto bad;
 232                 }
 233                 n = kzalloc(sizeof(*n), GFP_KERNEL);
 234                 if (!n) {
 235                         printk(KERN_ERR "security: ebitmap: out of memory\n");
 236                         rc = -ENOMEM;
 237                         goto bad;
 238                 }
 239
 240                 n->startbit = le32_to_cpu(buf[0]);
 241
 242                 if (n->startbit & (MAPSIZE - 1)) {
 243                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
 244                                "not a multiple of the map size (%Zd)\n",
 245                                n->startbit, MAPSIZE);
 246                         goto bad_free;
 247                 }
 248                 if (n->startbit > (e->highbit - MAPSIZE)) {
 249                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
 250                                "beyond the end of the bitmap (%Zd)\n",
 251                                n->startbit, (e->highbit - MAPSIZE));
 252                         goto bad_free;
 253                 }
 254                 rc = next_entry(&map, fp, sizeof(u64));
 255                 if (rc < 0) {
 256                         printk(KERN_ERR "security: ebitmap: truncated map\n");
 257                         goto bad_free;
 258                 }
 259                 n->map = le64_to_cpu(map);
 260
 261                 if (!n->map) {
 262                         printk(KERN_ERR "security: ebitmap: null map in "
 263                                "ebitmap (startbit %d)\n", n->startbit);
 264                         goto bad_free;
 265                 }
 266                 if (l) {
 267                         if (n->startbit <= l->startbit) {
 268                                 printk(KERN_ERR "security: ebitmap: start "
 269                                        "bit %d comes after start bit %d\n",
 270                                        n->startbit, l->startbit);
 271                                 goto bad_free;
 272                         }
 273                         l->next = n;
 274                 } else
 275                         e->node = n;
 276
 277                 l = n;
 278         }
 279
 280 ok:
 281         rc = 0;
 282 out:
 283         return rc;
 284 bad_free:
 285         kfree(n);
 286 bad:
 287         if (!rc)
 288                 rc = -EINVAL;
 289         ebitmap_destroy(e);
 290         goto out;
 291 }