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Some built-in stats #24

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Some built-in stats #24

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2 changes: 1 addition & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ OBJS = $(SRCS:.c=.o)
all: $(NAME)

$(NAME): $(OBJS)
$(CC) -o $(NAME) $(OBJS) $(LDFLAGS)
$(CC) -o $(NAME) $(OBJS) $(CFLAGS) $(LDFLAGS)

clean:
rm -f $(OBJS)
Expand Down
82 changes: 71 additions & 11 deletions main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,14 @@ see the "README.md" file for more details.
#include <openssl/hmac.h>
#include <stdbool.h>
#include <pthread.h>
#ifndef NO_STATS
#include <time.h>
#include <stdatomic.h>
#endif
#include "base64.h"

#define unlikely(x) __builtin_expect(!!(x), 0)

char *g_header_b64 = NULL; // Holds the Base64 header of the original JWT
char *g_payload_b64 = NULL; // Holds the Base64 payload of the original JWT
char *g_signature_b64 = NULL; // Holds the Base64 signature of the original JWT
Expand All @@ -37,6 +43,9 @@ size_t g_alphabet_len = 0;

char *g_found_secret = NULL;

// Information about how many HMACs we have attempted. We will report on timing unless
// compiled with -DNO_STATS

struct s_thread_data {
const EVP_MD *g_evp_md; // The hash function to apply the HMAC to

Expand All @@ -49,8 +58,31 @@ struct s_thread_data {

char starting_letter; // Each thread is assigned a first letter
size_t max_len; // And tries combinations up to a certain length

#ifndef NO_STATS
// Thread-local count of attempts since last report.
unsigned int g_attempts;
#endif
};

#ifndef NO_STATS
_Atomic unsigned int g_total_attempts = ATOMIC_VAR_INIT(0);

struct timespec ts_start, ts_end;

static double time_diff(struct timespec *end, struct timespec *start) {
return ((double)(end->tv_sec - start->tv_sec))
+ ((end->tv_nsec - start->tv_nsec) / 1000000000.0);
}

#define update_count(x) (x->g_attempts++)
#define report(x) atomic_fetch_add(&g_total_attempts, x->g_attempts)
#else
#define update_count(x)
#define report(x)
#endif


void init_thread_data(struct s_thread_data *data, char starting_letter, size_t max_len, const EVP_MD *evp_md) {
data->max_len = max_len;
data->starting_letter = starting_letter;
Expand All @@ -60,6 +92,9 @@ void init_thread_data(struct s_thread_data *data, char starting_letter, size_t m
data->g_result = malloc(EVP_MAX_MD_SIZE);
// Allocate the buffer used to hold the generated key
data->g_buffer = malloc(max_len + 1);
#ifndef NO_STATS
data->g_attempts = 0;
#endif
}

void destroy_thread_data(struct s_thread_data *data) {
Expand All @@ -69,13 +104,14 @@ void destroy_thread_data(struct s_thread_data *data) {

/**
* Check if the signature produced with "secret
* of size "secrent_len" (without the '\0') matches the original
* of size "secret_len" (without the '\0') matches the original
* signature.
* Return true if it matches, false otherwise
*/
bool check(struct s_thread_data *data, const char *secret, size_t secret_len) {
// If the secret was found by another thread, stop this thread
if (g_found_secret != NULL) {
report(data);
destroy_thread_data(data);
pthread_exit(NULL);
}
Expand All @@ -90,6 +126,7 @@ bool check(struct s_thread_data *data, const char *secret, size_t secret_len) {

// Compare the computed hash to the given decoded base64 signature.
// If there is a match, we just found the key.
update_count(data);
return memcmp(data->g_result, g_signature, g_signature_len) == 0;
}

Expand Down Expand Up @@ -139,6 +176,8 @@ char *brute_sequential(struct s_thread_data *data)
// so other threads stop, and stop the current thread. Congrats little
// thread!
g_found_secret = strndup(data->g_buffer, 1);

report(data);
return g_found_secret;
}

Expand All @@ -150,12 +189,15 @@ char *brute_sequential(struct s_thread_data *data)
// so other threads stop, and stop the current thread. Congrats little
// thread!
g_found_secret = strndup(data->g_buffer, i);

report(data);
return g_found_secret;
}
}

success:


report(data);
return NULL;
}

Expand All @@ -171,7 +213,7 @@ int main(int argc, char **argv) {

const EVP_MD *evp_md;
size_t max_len = 6;

// by default, use OpenSSL EVP_sha256 which corresponds to JSON HS256 (HMAC-SHA256)
const char *default_hmac_alg = "sha256";

Expand Down Expand Up @@ -203,17 +245,17 @@ int main(int argc, char **argv) {
if (argc > 4)
{
evp_md = EVP_get_digestbyname(argv[4]);
if (evp_md == NULL)
if (evp_md == NULL)
printf("Unknown message digest %s, will use default %s\n", argv[4], default_hmac_alg);
} else
{
evp_md = NULL;
evp_md = NULL;
}

if (evp_md == NULL)
if (evp_md == NULL)
{
evp_md = EVP_get_digestbyname(default_hmac_alg);
if (evp_md == NULL)
if (evp_md == NULL)
{
printf("Cannot initialize the default message digest %s, aborting\n", default_hmac_alg);
return 1;
Expand Down Expand Up @@ -248,6 +290,11 @@ int main(int argc, char **argv) {
struct s_thread_data *pointers_data[g_alphabet_len];
pthread_t *tid = malloc(g_alphabet_len * sizeof(pthread_t));

#ifndef NO_STATS
printf("Launching: %d threads\n", g_alphabet_len);
clock_gettime(CLOCK_MONOTONIC, &ts_start);
#endif

for (size_t i = 0; i < g_alphabet_len; i++) {
pointers_data[i] = malloc(sizeof(struct s_thread_data));
init_thread_data(pointers_data[i], g_alphabet[i], max_len, evp_md);
Expand All @@ -257,10 +304,23 @@ int main(int argc, char **argv) {
for (size_t i = 0; i < g_alphabet_len; i++)
pthread_join(tid[i], NULL);

if (g_found_secret == NULL)
printf("No solution found :-(\n");
else
printf("Secret is \"%s\"\n", g_found_secret);
if (g_found_secret == NULL)
printf("No solution found :-(\n");
else
printf("Secret is \"%s\"\n", g_found_secret);

#ifndef NO_STATS
clock_gettime(CLOCK_MONOTONIC, &ts_end);
double diff = time_diff(&ts_end, &ts_start);
uint64_t nthreads = g_alphabet_len;
double ops = g_total_attempts / diff;
double opth = g_total_attempts / nthreads;

printf("Made %ld attempts in %.4f seconds (ops/sec: %.3f)\n",
g_total_attempts, diff, ops);

printf("That is an avg of %.4f attempts per thread.\n", opth);
#endif

free(g_found_secret);
free(tid);
Expand Down