Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | } |