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/*
* PKCS #5 (Password-based Encryption)
* Copyright (c) 2009-2015, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/crypto.h"
#include "crypto/md5.h"
#include "crypto/sha1.h"
#include "asn1.h"
#include "pkcs5.h"
struct pkcs5_params {
enum pkcs5_alg {
PKCS5_ALG_UNKNOWN,
PKCS5_ALG_MD5_DES_CBC,
PKCS5_ALG_PBES2,
PKCS5_ALG_SHA1_3DES_CBC,
} alg;
u8 salt[64];
size_t salt_len;
unsigned int iter_count;
enum pbes2_enc_alg {
PBES2_ENC_ALG_UNKNOWN,
PBES2_ENC_ALG_DES_EDE3_CBC,
} enc_alg;
u8 iv[8];
size_t iv_len;
};
static int oid_is_rsadsi(struct asn1_oid *oid)
{
return oid->len >= 4 &&
oid->oid[0] == 1 /* iso */ &&
oid->oid[1] == 2 /* member-body */ &&
oid->oid[2] == 840 /* us */ &&
oid->oid[3] == 113549 /* rsadsi */;
}
static int pkcs5_is_oid(struct asn1_oid *oid, unsigned long alg)
{
return oid->len == 7 &&
oid_is_rsadsi(oid) &&
oid->oid[4] == 1 /* pkcs */ &&
oid->oid[5] == 5 /* pkcs-5 */ &&
oid->oid[6] == alg;
}
static int enc_alg_is_oid(struct asn1_oid *oid, unsigned long alg)
{
return oid->len == 6 &&
oid_is_rsadsi(oid) &&
oid->oid[4] == 3 /* encryptionAlgorithm */ &&
oid->oid[5] == alg;
}
static int pkcs12_is_pbe_oid(struct asn1_oid *oid, unsigned long alg)
{
return oid->len == 8 &&
oid_is_rsadsi(oid) &&
oid->oid[4] == 1 /* pkcs */ &&
oid->oid[5] == 12 /* pkcs-12 */ &&
oid->oid[6] == 1 /* pkcs-12PbeIds */ &&
oid->oid[7] == alg;
}
static enum pkcs5_alg pkcs5_get_alg(struct asn1_oid *oid)
{
if (pkcs5_is_oid(oid, 3)) /* pbeWithMD5AndDES-CBC (PBES1) */
return PKCS5_ALG_MD5_DES_CBC;
if (pkcs12_is_pbe_oid(oid, 3)) /* pbeWithSHAAnd3-KeyTripleDES-CBC */
return PKCS5_ALG_SHA1_3DES_CBC;
if (pkcs5_is_oid(oid, 13)) /* id-PBES2 (PBES2) */
return PKCS5_ALG_PBES2;
return PKCS5_ALG_UNKNOWN;
}
static int pkcs5_get_params_pbes2(struct pkcs5_params *params, const u8 *pos,
const u8 *enc_alg_end)
{
struct asn1_hdr hdr;
const u8 *end, *kdf_end;
struct asn1_oid oid;
char obuf[80];
/*
* RFC 2898, Ch. A.4
*
* PBES2-params ::= SEQUENCE {
* keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
* encryptionScheme AlgorithmIdentifier {{PBES2-Encs}} }
*
* PBES2-KDFs ALGORITHM-IDENTIFIER ::=
* { {PBKDF2-params IDENTIFIED BY id-PBKDF2}, ... }
*/
if (asn1_get_next(pos, enc_alg_end - pos, &hdr) < 0 ||
!asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected SEQUENCE (PBES2-params)");
return -1;
}
pos = hdr.payload;
end = hdr.payload + hdr.length;
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected SEQUENCE (keyDerivationFunc)");
return -1;
}
pos = hdr.payload;
kdf_end = end = hdr.payload + hdr.length;
if (asn1_get_oid(pos, end - pos, &oid, &pos)) {
wpa_printf(MSG_DEBUG,
"PKCS #5: Failed to parse OID (keyDerivationFunc algorithm)");
return -1;
}
asn1_oid_to_str(&oid, obuf, sizeof(obuf));
wpa_printf(MSG_DEBUG, "PKCS #5: PBES2 keyDerivationFunc algorithm %s",
obuf);
if (!pkcs5_is_oid(&oid, 12)) /* id-PBKDF2 */ {
wpa_printf(MSG_DEBUG,
"PKCS #5: Unsupported PBES2 keyDerivationFunc algorithm %s",
obuf);
return -1;
}
/*
* RFC 2898, C.
*
* PBKDF2-params ::= SEQUENCE {
* salt CHOICE {
* specified OCTET STRING,
* otherSource AlgorithmIdentifier {{PBKDF2-SaltSources}}
* },
* iterationCount INTEGER (1..MAX),
* keyLength INTEGER (1..MAX) OPTIONAL,
* prf AlgorithmIdentifier {{PBKDF2-PRFs}} DEFAULT
* algid-hmacWithSHA1
* }
*/
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected SEQUENCE (PBKDF2-params)");
return -1;
}
pos = hdr.payload;
end = hdr.payload + hdr.length;
/* For now, only support the salt CHOICE specified (OCTET STRING) */
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_octetstring(&hdr) ||
hdr.length > sizeof(params->salt)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected OCTET STRING (salt.specified)");
return -1;
}
pos = hdr.payload + hdr.length;
os_memcpy(params->salt, hdr.payload, hdr.length);
params->salt_len = hdr.length;
wpa_hexdump(MSG_DEBUG, "PKCS #5: salt", params->salt, params->salt_len);
/* iterationCount INTEGER */
if (asn1_get_next(pos, end - pos, &hdr) < 0 || !asn1_is_integer(&hdr)) {
asn1_unexpected(&hdr, "PKCS #5: Expected INTEGER");
return -1;
}
if (hdr.length == 1) {
params->iter_count = *hdr.payload;
} else if (hdr.length == 2) {
params->iter_count = WPA_GET_BE16(hdr.payload);
} else if (hdr.length == 4) {
params->iter_count = WPA_GET_BE32(hdr.payload);
} else {
wpa_hexdump(MSG_DEBUG,
"PKCS #5: Unsupported INTEGER value (iterationCount)",
hdr.payload, hdr.length);
return -1;
}
wpa_printf(MSG_DEBUG, "PKCS #5: iterationCount=0x%x",
params->iter_count);
if (params->iter_count == 0 || params->iter_count > 0xffff) {
wpa_printf(MSG_INFO, "PKCS #5: Unsupported iterationCount=0x%x",
params->iter_count);
return -1;
}
/* For now, ignore optional keyLength and prf */
pos = kdf_end;
/* encryptionScheme AlgorithmIdentifier {{PBES2-Encs}} */
if (asn1_get_next(pos, enc_alg_end - pos, &hdr) < 0 ||
!asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected SEQUENCE (encryptionScheme)");
return -1;
}
pos = hdr.payload;
end = hdr.payload + hdr.length;
if (asn1_get_oid(pos, end - pos, &oid, &pos)) {
wpa_printf(MSG_DEBUG,
"PKCS #5: Failed to parse OID (encryptionScheme algorithm)");
return -1;
}
asn1_oid_to_str(&oid, obuf, sizeof(obuf));
wpa_printf(MSG_DEBUG, "PKCS #5: PBES2 encryptionScheme algorithm %s",
obuf);
if (enc_alg_is_oid(&oid, 7)) {
params->enc_alg = PBES2_ENC_ALG_DES_EDE3_CBC;
} else {
wpa_printf(MSG_DEBUG,
"PKCS #5: Unsupported PBES2 encryptionScheme algorithm %s",
obuf);
return -1;
}
/*
* RFC 2898, B.2.2:
* The parameters field associated with this OID in an
* AlgorithmIdentifier shall have type OCTET STRING (SIZE(8)),
* specifying the initialization vector for CBC mode.
*/
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_octetstring(&hdr) || hdr.length != 8) {
asn1_unexpected(&hdr,
"PKCS #5: Expected OCTET STRING (SIZE(8)) (IV)");
return -1;
}
os_memcpy(params->iv, hdr.payload, hdr.length);
params->iv_len = hdr.length;
wpa_hexdump(MSG_DEBUG, "PKCS #5: IV", params->iv, params->iv_len);
return 0;
}
static int pkcs5_get_params(const u8 *enc_alg, size_t enc_alg_len,
struct pkcs5_params *params)
{
struct asn1_hdr hdr;
const u8 *enc_alg_end, *pos, *end;
struct asn1_oid oid;
char obuf[80];
/* AlgorithmIdentifier */
enc_alg_end = enc_alg + enc_alg_len;
os_memset(params, 0, sizeof(*params));
if (asn1_get_oid(enc_alg, enc_alg_end - enc_alg, &oid, &pos)) {
wpa_printf(MSG_DEBUG, "PKCS #5: Failed to parse OID "
"(algorithm)");
return -1;
}
asn1_oid_to_str(&oid, obuf, sizeof(obuf));
wpa_printf(MSG_DEBUG, "PKCS #5: encryption algorithm %s", obuf);
params->alg = pkcs5_get_alg(&oid);
if (params->alg == PKCS5_ALG_UNKNOWN) {
wpa_printf(MSG_INFO, "PKCS #5: unsupported encryption "
"algorithm %s", obuf);
return -1;
}
if (params->alg == PKCS5_ALG_PBES2)
return pkcs5_get_params_pbes2(params, pos, enc_alg_end);
/* PBES1 */
/*
* PKCS#5, Section 8
* PBEParameter ::= SEQUENCE {
* salt OCTET STRING SIZE(8),
* iterationCount INTEGER }
*
* Note: The same implementation can be used to parse the PKCS #12
* version described in RFC 7292, C:
* pkcs-12PbeParams ::= SEQUENCE {
* salt OCTET STRING,
* iterations INTEGER
* }
*/
if (asn1_get_next(pos, enc_alg_end - pos, &hdr) < 0 ||
!asn1_is_sequence(&hdr)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected SEQUENCE (PBEParameter)");
return -1;
}
pos = hdr.payload;
end = hdr.payload + hdr.length;
/* salt OCTET STRING SIZE(8) (PKCS #5) or OCTET STRING (PKCS #12) */
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_octetstring(&hdr) || hdr.length > sizeof(params->salt)) {
asn1_unexpected(&hdr,
"PKCS #5: Expected OCTETSTRING SIZE(8) (salt)");
return -1;
}
pos = hdr.payload + hdr.length;
os_memcpy(params->salt, hdr.payload, hdr.length);
params->salt_len = hdr.length;
wpa_hexdump(MSG_DEBUG, "PKCS #5: salt",
params->salt, params->salt_len);
/* iterationCount INTEGER */
if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
!asn1_is_integer(&hdr)) {
asn1_unexpected(&hdr, "PKCS #5: Expected INTEGER");
return -1;
}
if (hdr.length == 1)
params->iter_count = *hdr.payload;
else if (hdr.length == 2)
params->iter_count = WPA_GET_BE16(hdr.payload);
else if (hdr.length == 4)
params->iter_count = WPA_GET_BE32(hdr.payload);
else {
wpa_hexdump(MSG_DEBUG, "PKCS #5: Unsupported INTEGER value "
" (iterationCount)",
hdr.payload, hdr.length);
return -1;
}
wpa_printf(MSG_DEBUG, "PKCS #5: iterationCount=0x%x",
params->iter_count);
if (params->iter_count == 0 || params->iter_count > 0xffff) {
wpa_printf(MSG_INFO, "PKCS #5: Unsupported "
"iterationCount=0x%x", params->iter_count);
return -1;
}
return 0;
}
static struct crypto_cipher *
pkcs5_crypto_init_pbes2(struct pkcs5_params *params, const char *passwd)
{
u8 key[24];
if (params->enc_alg != PBES2_ENC_ALG_DES_EDE3_CBC ||
params->iv_len != 8)
return NULL;
wpa_hexdump_ascii_key(MSG_DEBUG, "PKCS #5: PBES2 password for PBKDF2",
passwd, os_strlen(passwd));
wpa_hexdump(MSG_DEBUG, "PKCS #5: PBES2 salt for PBKDF2",
params->salt, params->salt_len);
wpa_printf(MSG_DEBUG, "PKCS #5: PBES2 PBKDF2 iterations: %u",
params->iter_count);
if (pbkdf2_sha1(passwd, params->salt, params->salt_len,
params->iter_count, key, sizeof(key)) < 0)
return NULL;
wpa_hexdump_key(MSG_DEBUG, "PKCS #5: DES EDE3 key", key, sizeof(key));
wpa_hexdump(MSG_DEBUG, "PKCS #5: DES IV", params->iv, params->iv_len);
return crypto_cipher_init(CRYPTO_CIPHER_ALG_3DES, params->iv,
key, sizeof(key));
}
static void add_byte_array_mod(u8 *a, const u8 *b, size_t len)
{
size_t i;
unsigned int carry = 0;
for (i = len - 1; i < len; i--) {
carry = carry + a[i] + b[i];
a[i] = carry & 0xff;
carry >>= 8;
}
}
static int pkcs12_key_gen(const u8 *pw, size_t pw_len, const u8 *salt,
size_t salt_len, u8 id, unsigned int iter,
size_t out_len, u8 *out)
{
unsigned int u, v, S_len, P_len, i;
u8 *D = NULL, *I = NULL, *B = NULL, *pos;
int res = -1;
/* RFC 7292, B.2 */
u = SHA1_MAC_LEN;
v = 64;
/* D = copies of ID */
D = os_malloc(v);
if (!D)
goto done;
os_memset(D, id, v);
/* S = copies of salt; P = copies of password, I = S || P */
S_len = v * ((salt_len + v - 1) / v);
P_len = v * ((pw_len + v - 1) / v);
I = os_malloc(S_len + P_len);
if (!I)
goto done;
pos = I;
if (salt_len) {
for (i = 0; i < S_len; i++)
*pos++ = salt[i % salt_len];
}
if (pw_len) {
for (i = 0; i < P_len; i++)
*pos++ = pw[i % pw_len];
}
B = os_malloc(v);
if (!B)
goto done;
for (;;) {
u8 hash[SHA1_MAC_LEN];
const u8 *addr[2];
size_t len[2];
addr[0] = D;
len[0] = v;
addr[1] = I;
len[1] = S_len + P_len;
if (sha1_vector(2, addr, len, hash) < 0)
goto done;
addr[0] = hash;
len[0] = SHA1_MAC_LEN;
for (i = 1; i < iter; i++) {
if (sha1_vector(1, addr, len, hash) < 0)
goto done;
}
if (out_len <= u) {
os_memcpy(out, hash, out_len);
res = 0;
goto done;
}
os_memcpy(out, hash, u);
out += u;
out_len -= u;
/* I_j = (I_j + B + 1) mod 2^(v*8) */
/* B = copies of Ai (final hash value) */
for (i = 0; i < v; i++)
B[i] = hash[i % u];
inc_byte_array(B, v);
for (i = 0; i < S_len + P_len; i += v)
add_byte_array_mod(&I[i], B, v);
}
done:
os_free(B);
os_free(I);
os_free(D);
return res;
}
#define PKCS12_ID_ENC 1
#define PKCS12_ID_IV 2
#define PKCS12_ID_MAC 3
static struct crypto_cipher *
pkcs12_crypto_init_sha1(struct pkcs5_params *params, const char *passwd)
{
unsigned int i;
u8 *pw;
size_t pw_len;
u8 key[24];
u8 iv[8];
if (params->alg != PKCS5_ALG_SHA1_3DES_CBC)
return NULL;
pw_len = passwd ? os_strlen(passwd) : 0;
pw = os_malloc(2 * (pw_len + 1));
if (!pw)
return NULL;
if (pw_len) {
for (i = 0; i <= pw_len; i++)
WPA_PUT_BE16(&pw[2 * i], passwd[i]);
pw_len = 2 * (pw_len + 1);
}
if (pkcs12_key_gen(pw, pw_len, params->salt, params->salt_len,
PKCS12_ID_ENC, params->iter_count,
sizeof(key), key) < 0 ||
pkcs12_key_gen(pw, pw_len, params->salt, params->salt_len,
PKCS12_ID_IV, params->iter_count,
sizeof(iv), iv) < 0) {
os_free(pw);
return NULL;
}
os_free(pw);
wpa_hexdump_key(MSG_DEBUG, "PKCS #12: DES key", key, sizeof(key));
wpa_hexdump_key(MSG_DEBUG, "PKCS #12: DES IV", iv, sizeof(iv));
return crypto_cipher_init(CRYPTO_CIPHER_ALG_3DES, iv, key, sizeof(key));
}
static struct crypto_cipher * pkcs5_crypto_init(struct pkcs5_params *params,
const char *passwd)
{
unsigned int i;
u8 hash[MD5_MAC_LEN];
const u8 *addr[2];
size_t len[2];
if (params->alg == PKCS5_ALG_PBES2)
return pkcs5_crypto_init_pbes2(params, passwd);
if (params->alg == PKCS5_ALG_SHA1_3DES_CBC)
return pkcs12_crypto_init_sha1(params, passwd);
if (params->alg != PKCS5_ALG_MD5_DES_CBC)
return NULL;
addr[0] = (const u8 *) passwd;
len[0] = os_strlen(passwd);
addr[1] = params->salt;
len[1] = params->salt_len;
if (md5_vector(2, addr, len, hash) < 0)
return NULL;
addr[0] = hash;
len[0] = MD5_MAC_LEN;
for (i = 1; i < params->iter_count; i++) {
if (md5_vector(1, addr, len, hash) < 0)
return NULL;
}
/* TODO: DES key parity bits(?) */
wpa_hexdump_key(MSG_DEBUG, "PKCS #5: DES key", hash, 8);
wpa_hexdump_key(MSG_DEBUG, "PKCS #5: DES IV", hash + 8, 8);
return crypto_cipher_init(CRYPTO_CIPHER_ALG_DES, hash + 8, hash, 8);
}
u8 * pkcs5_decrypt(const u8 *enc_alg, size_t enc_alg_len,
const u8 *enc_data, size_t enc_data_len,
const char *passwd, size_t *data_len)
{
struct crypto_cipher *ctx;
u8 *eb, pad;
struct pkcs5_params params;
unsigned int i;
if (pkcs5_get_params(enc_alg, enc_alg_len, ¶ms) < 0) {
wpa_printf(MSG_DEBUG, "PKCS #5: Unsupported parameters");
return NULL;
}
ctx = pkcs5_crypto_init(¶ms, passwd);
if (ctx == NULL) {
wpa_printf(MSG_DEBUG, "PKCS #5: Failed to initialize crypto");
return NULL;
}
/* PKCS #5, Section 7 - Decryption process */
if (enc_data_len < 16 || enc_data_len % 8) {
wpa_printf(MSG_INFO, "PKCS #5: invalid length of ciphertext "
"%d", (int) enc_data_len);
crypto_cipher_deinit(ctx);
return NULL;
}
eb = os_malloc(enc_data_len);
if (eb == NULL) {
crypto_cipher_deinit(ctx);
return NULL;
}
if (crypto_cipher_decrypt(ctx, enc_data, eb, enc_data_len) < 0) {
wpa_printf(MSG_DEBUG, "PKCS #5: Failed to decrypt EB");
crypto_cipher_deinit(ctx);
os_free(eb);
return NULL;
}
crypto_cipher_deinit(ctx);
pad = eb[enc_data_len - 1];
if (pad > 8) {
wpa_printf(MSG_INFO, "PKCS #5: Invalid PS octet 0x%x", pad);
os_free(eb);
return NULL;
}
for (i = enc_data_len - pad; i < enc_data_len; i++) {
if (eb[i] != pad) {
wpa_hexdump(MSG_INFO, "PKCS #5: Invalid PS",
eb + enc_data_len - pad, pad);
os_free(eb);
return NULL;
}
}
wpa_hexdump_key(MSG_MSGDUMP, "PKCS #5: message M (encrypted key)",
eb, enc_data_len - pad);
*data_len = enc_data_len - pad;
return eb;
}
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