Page MenuHomeFreeBSD
Differential D29744 Diff 87375 contrib/wpa/hostapd/sae_pk_gen.c

Changeset View

Standalone View

View Options

contrib/wpa/hostapd/sae_pk_gen.c

  • This file was added.
/*
* SAE-PK password/modifier generator
* Copyright (c) 2020, The Linux Foundation
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "utils/base64.h"
#include "crypto/crypto.h"
#include "common/sae.h"
int main(int argc, char *argv[])
{
char *der = NULL;
size_t der_len;
struct crypto_ec_key *key = NULL;
struct wpabuf *pub = NULL;
u8 *data = NULL, *m;
size_t data_len;
char *b64 = NULL, *pw = NULL, *pos, *src;
int sec, j;
int ret = -1;
u8 hash[SAE_MAX_HASH_LEN];
char hash_hex[2 * SAE_MAX_HASH_LEN + 1];
u8 pw_base_bin[SAE_MAX_HASH_LEN];
u8 *dst;
int group;
size_t hash_len;
unsigned long long i, expected;
char m_hex[2 * SAE_PK_M_LEN + 1];
u32 sec_1b, val20;
wpa_debug_level = MSG_INFO;
if (os_program_init() < 0)
goto fail;
if (argc != 4) {
fprintf(stderr,
"usage: sae_pk_gen <DER ECPrivateKey file> <Sec:3|5> <SSID>\n");
goto fail;
}
sec = atoi(argv[2]);
if (sec != 3 && sec != 5) {
fprintf(stderr,
"Invalid Sec value (allowed values: 3 and 5)\n");
goto fail;
}
sec_1b = sec == 3;
expected = 1;
for (j = 0; j < sec; j++)
expected *= 256;
der = os_readfile(argv[1], &der_len);
if (!der) {
fprintf(stderr, "Could not read %s: %s\n",
argv[1], strerror(errno));
goto fail;
}
key = crypto_ec_key_parse_priv((u8 *) der, der_len);
if (!key) {
fprintf(stderr, "Could not parse ECPrivateKey\n");
goto fail;
}
pub = crypto_ec_key_get_subject_public_key(key);
if (!pub) {
fprintf(stderr, "Failed to build SubjectPublicKey\n");
goto fail;
}
group = crypto_ec_key_group(key);
switch (group) {
case 19:
hash_len = 32;
break;
case 20:
hash_len = 48;
break;
case 21:
hash_len = 64;
break;
default:
fprintf(stderr, "Unsupported private key group\n");
goto fail;
}
data_len = os_strlen(argv[3]) + SAE_PK_M_LEN + wpabuf_len(pub);
data = os_malloc(data_len);
if (!data) {
fprintf(stderr, "No memory for data buffer\n");
goto fail;
}
os_memcpy(data, argv[3], os_strlen(argv[3]));
m = data + os_strlen(argv[3]);
if (os_get_random(m, SAE_PK_M_LEN) < 0) {
fprintf(stderr, "Could not generate random Modifier M\n");
goto fail;
}
os_memcpy(m + SAE_PK_M_LEN, wpabuf_head(pub), wpabuf_len(pub));
fprintf(stderr, "Searching for a suitable Modifier M value\n");
for (i = 0;; i++) {
if (sae_hash(hash_len, data, data_len, hash) < 0) {
fprintf(stderr, "Hash failed\n");
goto fail;
}
if (hash[0] == 0 && hash[1] == 0) {
if ((hash[2] & 0xf0) == 0)
fprintf(stderr, "\r%3.2f%%",
100.0 * (double) i / (double) expected);
for (j = 2; j < sec; j++) {
if (hash[j])
break;
}
if (j == sec)
break;
}
inc_byte_array(m, SAE_PK_M_LEN);
}
if (wpa_snprintf_hex(m_hex, sizeof(m_hex), m, SAE_PK_M_LEN) < 0 ||
wpa_snprintf_hex(hash_hex, sizeof(hash_hex), hash, hash_len) < 0)
goto fail;
fprintf(stderr, "\nFound a valid hash in %llu iterations: %s\n",
i + 1, hash_hex);
b64 = base64_encode(der, der_len, NULL);
if (!b64)
goto fail;
src = pos = b64;
while (*src) {
if (*src != '\n')
*pos++ = *src;
src++;
}
*pos = '\0';
/* Skip 8*Sec bits and add Sec_1b as the every 20th bit starting with
* one. */
os_memset(pw_base_bin, 0, sizeof(pw_base_bin));
dst = pw_base_bin;
for (j = 0; j < 8 * (int) hash_len / 20; j++) {
val20 = sae_pk_get_be19(hash + sec);
val20 |= sec_1b << 19;
sae_pk_buf_shift_left_19(hash + sec, hash_len - sec);
if (j & 1) {
*dst |= (val20 >> 16) & 0x0f;
dst++;
*dst++ = (val20 >> 8) & 0xff;
*dst++ = val20 & 0xff;
} else {
*dst++ = (val20 >> 12) & 0xff;
*dst++ = (val20 >> 4) & 0xff;
*dst = (val20 << 4) & 0xf0;
}
}
if (wpa_snprintf_hex(hash_hex, sizeof(hash_hex),
pw_base_bin, hash_len - sec) >= 0)
fprintf(stderr, "PasswordBase binary data for base32: %s",
hash_hex);
pw = sae_pk_base32_encode(pw_base_bin, 20 * 3 - 5);
if (!pw)
goto fail;
printf("# SAE-PK password/M/private key for Sec=%d.\n", sec);
printf("sae_password=%s|pk=%s:%s\n", pw, m_hex, b64);
printf("# Longer passwords can be used for improved security at the cost of usability:\n");
for (j = 4; j <= ((int) hash_len * 8 + 5 - 8 * sec) / 19; j++) {
os_free(pw);
pw = sae_pk_base32_encode(pw_base_bin, 20 * j - 5);
if (pw)
printf("# %s\n", pw);
}
ret = 0;
fail:
os_free(der);
wpabuf_free(pub);
crypto_ec_key_deinit(key);
os_free(data);
os_free(b64);
os_free(pw);
os_program_deinit();
return ret;
}