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         __le32 buf[3];
 200         u32 mapsize, count, i;
 201         __le64 map;
 202
 203         ebitmap_init(e);
 204
 205         rc = next_entry(buf, fp, sizeof buf);
 206         if (rc < 0)
 207                 goto out;
 208
 209         mapsize = le32_to_cpu(buf[0]);
 210         e->highbit = le32_to_cpu(buf[1]);
 211         count = le32_to_cpu(buf[2]);
 212
 213         if (mapsize != MAPSIZE) {
 214                 printk(KERN_ERR "security: ebitmap: map size %u does not "
 215                        "match my size %Zd (high bit was %d)\n", mapsize,
 216                        MAPSIZE, e->highbit);
 217                 goto bad;
 218         }
 219         if (!e->highbit) {
 220                 e->node = NULL;
 221                 goto ok;
 222         }
 223         if (e->highbit & (MAPSIZE - 1)) {
 224                 printk(KERN_ERR "security: ebitmap: high bit (%d) is not a "
 225                        "multiple of the map size (%Zd)\n", e->highbit, MAPSIZE);
 226                 goto bad;
 227         }
 228         l = NULL;
 229         for (i = 0; i < count; i++) {
 230                 rc = next_entry(buf, fp, sizeof(u32));
 231                 if (rc < 0) {
 232                         printk(KERN_ERR "security: ebitmap: truncated map\n");
 233                         goto bad;
 234                 }
 235                 n = kmalloc(sizeof(*n), GFP_KERNEL);
 236                 if (!n) {
 237                         printk(KERN_ERR "security: ebitmap: out of memory\n");
 238                         rc = -ENOMEM;
 239                         goto bad;
 240                 }
 241                 memset(n, 0, sizeof(*n));
 242
 243                 n->startbit = le32_to_cpu(buf[0]);
 244
 245                 if (n->startbit & (MAPSIZE - 1)) {
 246                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
 247                                "not a multiple of the map size (%Zd)\n",
 248                                n->startbit, MAPSIZE);
 249                         goto bad_free;
 250                 }
 251                 if (n->startbit > (e->highbit - MAPSIZE)) {
 252                         printk(KERN_ERR "security: ebitmap start bit (%d) is "
 253                                "beyond the end of the bitmap (%Zd)\n",
 254                                n->startbit, (e->highbit - MAPSIZE));
 255                         goto bad_free;
 256                 }
 257                 rc = next_entry(&map, fp, sizeof(u64));
 258                 if (rc < 0) {
 259                         printk(KERN_ERR "security: ebitmap: truncated map\n");
 260                         goto bad_free;
 261                 }
 262                 n->map = le64_to_cpu(map);
 263
 264                 if (!n->map) {
 265                         printk(KERN_ERR "security: ebitmap: null map in "
 266                                "ebitmap (startbit %d)\n", n->startbit);
 267                         goto bad_free;
 268                 }
 269                 if (l) {
 270                         if (n->startbit <= l->startbit) {
 271                                 printk(KERN_ERR "security: ebitmap: start "
 272                                        "bit %d comes after start bit %d\n",
 273                                        n->startbit, l->startbit);
 274                                 goto bad_free;
 275                         }
 276                         l->next = n;
 277                 } else
 278                         e->node = n;
 279
 280                 l = n;
 281         }
 282
 283 ok:
 284         rc = 0;
 285 out:
 286         return rc;
 287 bad_free:
 288         kfree(n);
 289 bad:
 290         if (!rc)
 291                 rc = -EINVAL;
 292         ebitmap_destroy(e);
 293         goto out;
 294 }