You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
strongswan/scripts/timeattack.c

418 lines
9.0 KiB

#include <stdio.h>
#include <time.h>
#include <library.h>
typedef bool (*attackfn_t)(void *subj, u_char *data, size_t len);
static void start_timing(struct timespec *start)
{
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, start);
}
static uint64_t end_timing(struct timespec *start)
{
struct timespec end;
clock_gettime(CLOCK_THREAD_CPUTIME_ID, &end);
return (end.tv_nsec - start->tv_nsec) +
(end.tv_sec - start->tv_sec) * 1000000000;
}
static int intcmp(const void *a, const void *b)
{
return *(uint64_t*)a - *(uint64_t*)b;
}
static uint64_t median(uint64_t *m, int count)
{
qsort(m, count, sizeof(uint64_t), intcmp);
return m[count / 2];
}
static bool timeattack(attackfn_t attackfn, void *subj, size_t dlen,
u_int iterations, u_int distance)
{
struct timespec start;
u_char test[dlen];
uint64_t mini, maxi, t[256], m[256][10];
float fastdist = 0, slowdist = 0;
int i, j, k, l, byte, limit, retry = 0;
int fastest = 0, slowest = 0;
memset(test, 0, dlen);
/* do some iterations to fill caches */
for (i = 0; i < iterations; i++)
{
attackfn(subj, test, dlen);
}
for (byte = 0; byte < dlen;)
{
memset(t, 0, sizeof(t));
memset(m, 0, sizeof(m));
limit = iterations * (retry + 1);
/* measure timing for all patterns in next byte */
for (k = 0; k < 10; k++)
{
for (j = 0; j < 256; j++)
{
for (l = 0; l < 100; l++)
{
test[byte] = j;
start_timing(&start);
for (i = 0; i < limit; i++)
{
attackfn(subj, test, dlen);
}
m[j][k] += end_timing(&start);
}
}
}
for (j = 0; j < 256; j++)
{
t[j] = median(m[j], countof(m[j]));
}
/* find fastest/slowest runs */
mini = ~0;
maxi = 0;
for (j = 0; j < 256; j++)
{
if (t[j] < mini)
{
mini = min(t[j], mini);
fastest = j;
}
if (t[j] > maxi)
{
maxi = max(t[j], maxi);
slowest = j;
}
}
/* calculate distance to next result */
mini = ~0;
maxi = 0;
for (j = 0; j < 256; j++)
{
if (fastest != j && t[j] < mini)
{
mini = min(t[j], mini);
fastdist = (float)(t[j] - t[fastest]) / distance;
}
if (slowest != j && t[j] > maxi)
{
maxi = max(t[j], maxi);
slowdist = (float)(t[slowest] - t[j]) / distance;
}
}
if (fastdist > 1.0f)
{
fprintf(stderr, "byte %02d: %02x (fastest, dist %02.2f)\n",
byte, fastest, fastdist);
test[byte] = fastest;
retry = 0;
byte++;
}
else if (slowdist > 1.0f)
{
fprintf(stderr, "byte %02d: %02x (slowest, dist %02.2f)\n",
byte, slowest, slowdist);
test[byte] = slowest;
retry = 0;
byte++;
}
else
{
if (retry++ > 5 && byte > 0)
{
fprintf(stderr, "distance fastest %02.2f (%02x), "
"slowest %02.2f (%02x), stepping back\n",
fastdist, fastest, slowdist, slowest);
test[byte--] = 0;
}
else if (retry < 10)
{
fprintf(stderr, "distance fastest %02.2f (%02x), "
"slowest %02.2f (%02x), retrying (%d)\n",
fastdist, fastest, slowdist, slowest, retry);
}
else
{
printf("attack failed, giving up\n");
return FALSE;
}
}
}
if (attackfn(subj, test, dlen))
{
printf("attack successful with %b\n", test, dlen);
return TRUE;
}
printf("attack failed with %b\n", test, dlen);
return FALSE;
}
CALLBACK(attack_memeq1, bool,
u_char *subj, u_char *data, size_t len)
{
return memeq(data, subj, len);
}
CALLBACK(attack_memeq2, bool,
u_char *subj, u_char *data, size_t len)
{
return memeq(subj, data, len);
}
CALLBACK(attack_memeq3, bool,
u_char *subj, u_char *data, size_t len)
{
int i;
for (i = 0; i < len; i++)
{
if (subj[i] != data[i])
{
return FALSE;
}
}
return TRUE;
}
CALLBACK(attack_memeq4, bool,
u_char *subj, u_char *data, size_t len)
{
int i, m = 0;
for (i = 0; i < len; i++)
{
m |= subj[i] != data[i];
}
return !m;
}
CALLBACK(attack_memeq5, bool,
u_char *subj, u_char *data, size_t len)
{
return memeq_const(subj, data, len);
}
static bool attack_memeq(char *name, u_int iterations, u_int distance)
{
struct {
char *name;
attackfn_t fn;
} attacks[] = {
{ "memeq1", attack_memeq1 },
{ "memeq2", attack_memeq2 },
{ "memeq3", attack_memeq3 },
{ "memeq4", attack_memeq4 },
{ "memeq5", attack_memeq5 },
};
u_char exp[16];
int i;
srandom(time(NULL));
for (i = 0; i < sizeof(exp); i++)
{
exp[i] = random();
}
fprintf(stderr, "attacking %b\n", exp, sizeof(exp));
for (i = 0; i < countof(attacks); i++)
{
if (streq(name, attacks[i].name))
{
return timeattack(attacks[i].fn, exp, sizeof(exp),
iterations, distance);
}
}
return FALSE;
}
CALLBACK(attack_chunk1, bool,
u_char *subj, u_char *data, size_t len)
{
return chunk_equals(chunk_create(subj, len), chunk_create(data, len));
}
CALLBACK(attack_chunk2, bool,
u_char *subj, u_char *data, size_t len)
{
return chunk_equals_const(chunk_create(subj, len), chunk_create(data, len));
}
static bool attack_chunk(char *name, u_int iterations, u_int distance)
{
struct {
char *name;
attackfn_t fn;
} attacks[] = {
{ "chunk1", attack_chunk1 },
{ "chunk2", attack_chunk2 },
};
u_char exp[16];
int i;
srandom(time(NULL));
for (i = 0; i < sizeof(exp); i++)
{
exp[i] = random();
}
fprintf(stderr, "attacking %b\n", exp, sizeof(exp));
for (i = 0; i < countof(attacks); i++)
{
if (streq(name, attacks[i].name))
{
return timeattack(attacks[i].fn, exp, sizeof(exp),
iterations, distance);
}
}
return FALSE;
}
CALLBACK(attack_aead, bool,
aead_t *aead, u_char *data, size_t len)
{
u_char iv[aead->get_iv_size(aead)];
memset(iv, 0, sizeof(iv));
return aead->decrypt(aead, chunk_create(data, len), chunk_empty,
chunk_from_thing(iv), NULL);
}
static bool attack_aeads(encryption_algorithm_t alg, size_t key_size,
u_int iterations, u_int distance)
{
u_char buf[64];
aead_t *aead;
bool res;
aead = lib->crypto->create_aead(lib->crypto, alg, key_size, 0);
if (!aead)
{
fprintf(stderr, "creating AEAD %N failed\n",
encryption_algorithm_names, alg);
return FALSE;
}
memset(buf, 0xe3, sizeof(buf));
if (!aead->set_key(aead, chunk_create(buf, aead->get_key_size(aead))))
{
aead->destroy(aead);
return FALSE;
}
memset(buf, 0, aead->get_iv_size(aead));
if (!aead->encrypt(aead, chunk_create(buf, 0), chunk_empty,
chunk_create(buf, aead->get_iv_size(aead)), NULL))
{
aead->destroy(aead);
return FALSE;
}
fprintf(stderr, "attacking %b\n", buf, aead->get_icv_size(aead));
res = timeattack(attack_aead, aead, aead->get_icv_size(aead),
iterations, distance);
aead->destroy(aead);
return res;
}
CALLBACK(attack_signer, bool,
signer_t *signer, u_char *data, size_t len)
{
return signer->verify_signature(signer, chunk_empty, chunk_create(data, len));
}
static bool attack_signers(integrity_algorithm_t alg,
u_int iterations, u_int distance)
{
u_char buf[64];
signer_t *signer;
bool res;
signer = lib->crypto->create_signer(lib->crypto, alg);
if (!signer)
{
fprintf(stderr, "creating signer %N failed\n",
integrity_algorithm_names, alg);
return FALSE;
}
memset(buf, 0xe3, sizeof(buf));
if (!signer->set_key(signer, chunk_create(buf, signer->get_key_size(signer))))
{
signer->destroy(signer);
return FALSE;
}
if (!signer->get_signature(signer, chunk_empty, buf))
{
signer->destroy(signer);
return FALSE;
}
fprintf(stderr, "attacking %b\n", buf, signer->get_block_size(signer));
res = timeattack(attack_signer, signer, signer->get_block_size(signer),
iterations, distance);
signer->destroy(signer);
return res;
}
static bool attack_transform(char *name, u_int iterations, u_int distance)
{
const proposal_token_t *token;
token = lib->proposal->get_token(lib->proposal, name);
if (!token)
{
fprintf(stderr, "algorithm '%s' unknown\n", name);
return FALSE;
}
switch (token->type)
{
case ENCRYPTION_ALGORITHM:
if (encryption_algorithm_is_aead(token->algorithm))
{
return attack_aeads(token->algorithm, token->keysize / 8,
iterations, distance);
}
fprintf(stderr, "can't attack a crypter\n");
return FALSE;
case INTEGRITY_ALGORITHM:
return attack_signers(token->algorithm, iterations, distance);
default:
fprintf(stderr, "can't attack a %N\n", transform_type_names, token->type);
return FALSE;
}
}
int main(int argc, char *argv[])
{
library_init(NULL, "timeattack");
atexit(library_deinit);
lib->plugins->load(lib->plugins, getenv("PLUGINS") ?: PLUGINS);
if (argc < 3)
{
fprintf(stderr, "usage: %s <attack> <iterations> <distance>\n", argv[0]);
fprintf(stderr, " <attack>: memeq[1-5] / chunk[1-2] / aead / signer\n");
fprintf(stderr, " <iterations>: number of invocations * 1000\n");
fprintf(stderr, " <distance>: time difference in ns for a hit\n");
fprintf(stderr, " example: %s memeq1 100 500\n", argv[0]);
fprintf(stderr, " example: %s aes128gcm16 100 4000\n", argv[0]);
return 1;
}
if (strpfx(argv[1], "memeq"))
{
return !attack_memeq(argv[1], atoi(argv[2]), atoi(argv[3]));
}
if (strpfx(argv[1], "chunk"))
{
return !attack_chunk(argv[1], atoi(argv[2]), atoi(argv[3]));
}
return !attack_transform(argv[1], atoi(argv[2]), atoi(argv[3]));
}