scripts/timeattack.c

   1 #include <stdio.h>
   2 #include <time.h>
   3
   4 #include <library.h>
   5
   6 typedef bool (*attackfn_t)(void *subj, u_char *data, size_t len);
   7
   8 static void start_timing(struct timespec *start)
   9 {
  10         clock_gettime(CLOCK_PROCESS_CPUTIME_ID, start);
  11 }
  12
  13 static u_int64_t end_timing(struct timespec *start)
  14 {
  15         struct timespec end;
  16
  17         clock_gettime(CLOCK_THREAD_CPUTIME_ID, &end);
  18         return (end.tv_nsec - start->tv_nsec) +
  19                    (end.tv_sec - start->tv_sec) * 1000000000;
  20 }
  21
  22 static int intcmp(const void *a, const void *b)
  23 {
  24         return *(u_int64_t*)a - *(u_int64_t*)b;
  25 }
  26
  27 static u_int64_t median(u_int64_t *m, int count)
  28 {
  29         qsort(m, count, sizeof(u_int64_t), intcmp);
  30         return m[count / 2];
  31 }
  32
  33 static bool timeattack(attackfn_t attackfn, void *subj, size_t dlen,
  34                                            u_int iterations, u_int distance)
  35 {
  36         struct timespec start;
  37         u_char test[dlen];
  38         u_int64_t mini, maxi, t[256], m[256][10];
  39         float fastdist = 0, slowdist = 0;
  40         int i, j, k, l, byte, limit, retry = 0;
  41         int fastest = 0, slowest = 0;
  42
  43         memset(test, 0, dlen);
  44
  45         /* do some iterations to fill caches */
  46         for (i = 0; i < iterations; i++)
  47         {
  48                 attackfn(subj, test, dlen);
  49         }
  50
  51         for (byte = 0; byte < dlen;)
  52         {
  53                 memset(t, 0, sizeof(t));
  54                 memset(m, 0, sizeof(m));
  55
  56                 limit = iterations * (retry + 1);
  57
  58                 /* measure timing for all patterns in next byte */
  59                 for (k = 0; k < 10; k++)
  60                 {
  61                         for (j = 0; j < 256; j++)
  62                         {
  63                                 for (l = 0; l < 100; l++)
  64                                 {
  65                                         test[byte] = j;
  66                                         start_timing(&start);
  67                                         for (i = 0; i < limit; i++)
  68                                         {
  69                                                 attackfn(subj, test, dlen);
  70                                         }
  71                                         m[j][k] += end_timing(&start);
  72                                 }
  73                         }
  74                 }
  75
  76                 for (j = 0; j < 256; j++)
  77                 {
  78                         t[j] = median(m[j], countof(m[j]));
  79                 }
  80
  81                 /* find fastest/slowest runs */
  82                 mini = ~0;
  83                 maxi = 0;
  84                 for (j = 0; j < 256; j++)
  85                 {
  86                         if (t[j] < mini)
  87                         {
  88                                 mini = min(t[j], mini);
  89                                 fastest = j;
  90                         }
  91                         if (t[j] > maxi)
  92                         {
  93                                 maxi = max(t[j], maxi);
  94                                 slowest = j;
  95                         }
  96                 }
  97                 /* calculate distance to next result */
  98                 mini = ~0;
  99                 maxi = 0;
 100                 for (j = 0; j < 256; j++)
 101                 {
 102                         if (fastest != j && t[j] < mini)
 103                         {
 104                                 mini = min(t[j], mini);
 105                                 fastdist = (float)(t[j] - t[fastest]) / distance;
 106                         }
 107                         if (slowest != j && t[j] > maxi)
 108                         {
 109                                 maxi = max(t[j], maxi);
 110                                 slowdist = (float)(t[slowest] - t[j]) / distance;
 111                         }
 112                 }
 113                 if (fastdist > 1.0f)
 114                 {
 115                         fprintf(stderr, "byte %02d: %02x (fastest, dist %02.2f)\n",
 116                                         byte, fastest, fastdist);
 117                         test[byte] = fastest;
 118                         retry = 0;
 119                         byte++;
 120                 }
 121                 else if (slowdist > 1.0f)
 122                 {
 123                         fprintf(stderr, "byte %02d: %02x (slowest, dist %02.2f)\n",
 124                                         byte, slowest, slowdist);
 125                         test[byte] = slowest;
 126                         retry = 0;
 127                         byte++;
 128                 }
 129                 else
 130                 {
 131                         if (retry++ > 5 && byte > 0)
 132                         {
 133                                 fprintf(stderr, "distance fastest %02.2f (%02x), "
 134                                                 "slowest %02.2f (%02x), stepping back\n",
 135                                                 fastdist, fastest, slowdist, slowest);
 136                                 test[byte--] = 0;
 137                         }
 138                         else if (retry < 10)
 139                         {
 140                                 fprintf(stderr, "distance fastest %02.2f (%02x), "
 141                                                 "slowest %02.2f (%02x), retrying (%d)\n",
 142                                                 fastdist, fastest, slowdist, slowest, retry);
 143                         }
 144                         else
 145                         {
 146                                 printf("attack failed, giving up\n");
 147                                 return FALSE;
 148                         }
 149                 }
 150         }
 151         if (attackfn(subj, test, dlen))
 152         {
 153                 printf("attack successful with %b\n", test, dlen);
 154                 return TRUE;
 155         }
 156         printf("attack failed with %b\n", test, dlen);
 157         return FALSE;
 158 }
 159
 160 CALLBACK(attack_memeq1, bool,
 161         u_char *subj, u_char *data, size_t len)
 162 {
 163         return memeq(data, subj, len);
 164 }
 165
 166 CALLBACK(attack_memeq2, bool,
 167         u_char *subj, u_char *data, size_t len)
 168 {
 169         return memeq(subj, data, len);
 170 }
 171
 172 CALLBACK(attack_memeq3, bool,
 173         u_char *subj, u_char *data, size_t len)
 174 {
 175         int i;
 176
 177         for (i = 0; i < len; i++)
 178         {
 179                 if (subj[i] != data[i])
 180                 {
 181                         return FALSE;
 182                 }
 183         }
 184         return TRUE;
 185 }
 186
 187 CALLBACK(attack_memeq4, bool,
 188         u_char *subj, u_char *data, size_t len)
 189 {
 190         int i, m = 0;
 191
 192         for (i = 0; i < len; i++)
 193         {
 194                 m |= subj[i] != data[i];
 195         }
 196         return !m;
 197 }
 198
 199 static bool attack_memeq(char *name, u_int iterations, u_int distance)
 200 {
 201         struct {
 202                 char *name;
 203                 attackfn_t fn;
 204         } attacks[] = {
 205                 { "memeq1", attack_memeq1 },
 206                 { "memeq2", attack_memeq2 },
 207                 { "memeq3", attack_memeq3 },
 208                 { "memeq4", attack_memeq4 },
 209         };
 210         u_char exp[16];
 211         int i;
 212
 213         srandom(time(NULL));
 214         for (i = 0; i < sizeof(exp); i++)
 215         {
 216                 exp[i] = random();
 217         }
 218         fprintf(stderr, "attacking %b\n", exp, sizeof(exp));
 219
 220         for (i = 0; i < countof(attacks); i++)
 221         {
 222                 if (streq(name, attacks[i].name))
 223                 {
 224                         return timeattack(attacks[i].fn, exp, sizeof(exp),
 225                                                           iterations, distance);
 226                 }
 227         }
 228         return FALSE;
 229 }
 230
 231 CALLBACK(attack_aead, bool,
 232         aead_t *aead, u_char *data, size_t len)
 233 {
 234         u_char iv[aead->get_iv_size(aead)];
 235
 236         memset(iv, 0, sizeof(iv));
 237         return aead->decrypt(aead, chunk_create(data, len), chunk_empty,
 238                                                  chunk_from_thing(iv), NULL);
 239 }
 240
 241 static bool attack_aeads(encryption_algorithm_t alg, size_t key_size,
 242                                                  u_int iterations, u_int distance)
 243 {
 244         u_char buf[64];
 245         aead_t *aead;
 246         bool res;
 247
 248         aead = lib->crypto->create_aead(lib->crypto, alg, key_size, 0);
 249         if (!aead)
 250         {
 251                 fprintf(stderr, "creating AEAD %N failed\n",
 252                                 encryption_algorithm_names, alg);
 253                 return FALSE;
 254         }
 255         memset(buf, 0xe3, sizeof(buf));
 256         if (!aead->set_key(aead, chunk_create(buf, aead->get_key_size(aead))))
 257         {
 258                 aead->destroy(aead);
 259                 return FALSE;
 260         }
 261         memset(buf, 0, aead->get_iv_size(aead));
 262         if (!aead->encrypt(aead, chunk_create(buf, 0), chunk_empty,
 263                                            chunk_create(buf, aead->get_iv_size(aead)), NULL))
 264         {
 265                 aead->destroy(aead);
 266                 return FALSE;
 267         }
 268         fprintf(stderr, "attacking %b\n", buf, aead->get_icv_size(aead));
 269
 270         res = timeattack(attack_aead, aead, aead->get_icv_size(aead),
 271                                          iterations, distance);
 272         aead->destroy(aead);
 273         return res;
 274 }
 275
 276 CALLBACK(attack_signer, bool,
 277         signer_t *signer, u_char *data, size_t len)
 278 {
 279         return signer->verify_signature(signer, chunk_empty, chunk_create(data, len));
 280 }
 281
 282 static bool attack_signers(integrity_algorithm_t alg,
 283                                                    u_int iterations, u_int distance)
 284 {
 285         u_char buf[64];
 286         signer_t *signer;
 287         bool res;
 288
 289         signer = lib->crypto->create_signer(lib->crypto, alg);
 290         if (!signer)
 291         {
 292                 fprintf(stderr, "creating signer %N failed\n",
 293                                 integrity_algorithm_names, alg);
 294                 return FALSE;
 295         }
 296         memset(buf, 0xe3, sizeof(buf));
 297         if (!signer->set_key(signer, chunk_create(buf, signer->get_key_size(signer))))
 298         {
 299                 signer->destroy(signer);
 300                 return FALSE;
 301         }
 302         if (!signer->get_signature(signer, chunk_empty, buf))
 303         {
 304                 signer->destroy(signer);
 305                 return FALSE;
 306         }
 307         fprintf(stderr, "attacking %b\n", buf, signer->get_block_size(signer));
 308
 309         res = timeattack(attack_signer, signer, signer->get_block_size(signer),
 310                                          iterations, distance);
 311         signer->destroy(signer);
 312         return res;
 313 }
 314
 315 static bool attack_transform(char *name, u_int iterations, u_int distance)
 316 {
 317         const proposal_token_t *token;
 318
 319         token = lib->proposal->get_token(lib->proposal, name);
 320         if (!token)
 321         {
 322                 fprintf(stderr, "algorithm '%s' unknown\n", name);
 323                 return FALSE;
 324         }
 325
 326         switch (token->type)
 327         {
 328                 case ENCRYPTION_ALGORITHM:
 329                         if (encryption_algorithm_is_aead(token->algorithm))
 330                         {
 331                                 return attack_aeads(token->algorithm, token->keysize / 8,
 332                                                                         iterations, distance);
 333                         }
 334                         fprintf(stderr, "can't attack a crypter\n");
 335                         return FALSE;
 336                 case INTEGRITY_ALGORITHM:
 337                         return attack_signers(token->algorithm, iterations, distance);
 338                 default:
 339                         fprintf(stderr, "can't attack a %N\n", transform_type_names, token->type);
 340                         return FALSE;
 341         }
 342 }
 343
 344 int main(int argc, char *argv[])
 345 {
 346         library_init(NULL, "timeattack");
 347         atexit(library_deinit);
 348         lib->plugins->load(lib->plugins, getenv("PLUGINS") ?: PLUGINS);
 349
 350         if (argc < 3)
 351         {
 352                 fprintf(stderr, "usage: %s <attack> <iterations> <distance>\n", argv[0]);
 353                 fprintf(stderr, "  <attack>: memeq[1-4] / aead / signer\n");
 354                 fprintf(stderr, "  <iterations>: number of invocations * 1000\n");
 355                 fprintf(stderr, "  <distance>: time difference in ns for a hit\n");
 356                 fprintf(stderr, "  example: %s memeq1 100 500\n", argv[0]);
 357                 fprintf(stderr, "  example: %s aes128gcm16 100 4000\n", argv[0]);
 358                 return 1;
 359         }
 360         if (strpfx(argv[1], "memeq"))
 361         {
 362                 return !attack_memeq(argv[1], atoi(argv[2]), atoi(argv[3]));
 363         }
 364         return !attack_transform(argv[1], atoi(argv[2]), atoi(argv[3]));
 365 }