/*
* Copyright(C) 2006 Cameron Rich
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* Process PKCS#8/PKCS#12 keys.
*
* The decoding of a PKCS#12 key is fairly specific - this code was tested on a
* key generated with:
*
* openssl pkcs12 -export -in axTLS.x509_1024.pem -inkey axTLS.key_1024.pem
* -keypbe PBE-SHA1-RC4-128 -certpbe PBE-SHA1-RC4-128
* -name "p12_withoutCA" -out axTLS.withoutCA.p12 -password pass:abcd
*
* or with a certificate chain:
*
* openssl pkcs12 -export -in axTLS.x509_1024.pem -inkey axTLS.key_1024.pem
* -certfile axTLS.ca_x509.pem -keypbe PBE-SHA1-RC4-128 -certpbe
* PBE-SHA1-RC4-128 -name "p12_withCA" -out axTLS.withCA.p12 -password pass:abcd
*
* Note that the PBE has to be specified with PBE-SHA1-RC4-128. The
* private/public keys/certs have to use RSA encryption. Both the integrity
* and privacy passwords are the same.
*
* The PKCS#8 files were generated with something like:
*
* PEM format:
* openssl pkcs8 -in axTLS.key_512.pem -passout pass:abcd -topk8 -v1
* PBE-SHA1-RC4-128 -out axTLS.encrypted_pem.p8
*
* DER format:
* openssl pkcs8 -in axTLS.key_512.pem -passout pass:abcd -topk8 -outform DER
* -v1 PBE-SHA1-RC4-128 -out axTLS.encrypted.p8
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "ssl.h"
/* all commented out if not used */
#ifdef CONFIG_SSL_USE_PKCS12
#define BLOCK_SIZE 64
#define PKCS12_KEY_ID 1
#define PKCS12_IV_ID 2
#define PKCS12_MAC_ID 3
static char *make_uni_pass(const char *password, int *uni_pass_len);
static int p8_decrypt(const char *uni_pass, int uni_pass_len,
const uint8_t *salt, int iter,
uint8_t *priv_key, int priv_key_len, int id);
static int p8_add_key(SSL_CTX *ssl_ctx, uint8_t *priv_key);
static int get_pbe_params(uint8_t *buf, int *offset,
const uint8_t **salt, int *iterations);
/*
* Take a raw pkcs8 block and then decrypt it and turn it into a normal key.
*/
int pkcs8_decode(SSL_CTX *ssl_ctx, SSLObjLoader *ssl_obj, const char *password)
{
uint8_t *buf = ssl_obj->buf;
int len, offset = 0;
int iterations;
int ret = SSL_NOT_OK;
uint8_t *version = NULL;
const uint8_t *salt;
uint8_t *priv_key;
int uni_pass_len;
char *uni_pass = make_uni_pass(password, &uni_pass_len);
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0)
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: Invalid p8 ASN.1 file\n");
#endif
goto error;
}
/* unencrypted key? */
if (asn1_get_int(buf, &offset, &version) > 0 && *version == 0)
{
ret = p8_add_key(ssl_ctx, buf);
goto error;
}
if (get_pbe_params(buf, &offset, &salt, &iterations) < 0)
goto error;
if ((len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
goto error;
priv_key = &buf[offset];
p8_decrypt(uni_pass, uni_pass_len, salt,
iterations, priv_key, len, PKCS12_KEY_ID);
ret = p8_add_key(ssl_ctx, priv_key);
error:
free(version);
free(uni_pass);
return ret;
}
/*
* Take the unencrypted pkcs8 and turn it into a private key
*/
static int p8_add_key(SSL_CTX *ssl_ctx, uint8_t *priv_key)
{
uint8_t *buf = priv_key;
int len, offset = 0;
int ret = SSL_NOT_OK;
/* Skip the preamble and go straight to the private key.
We only support rsaEncryption (1.2.840.113549.1.1.1) */
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(buf, &offset, ASN1_INTEGER) < 0 ||
asn1_skip_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
goto error;
ret = asn1_get_private_key(&buf[offset], len, &ssl_ctx->rsa_ctx);
error:
return ret;
}
/*
* Create the unicode password
*/
static char *make_uni_pass(const char *password, int *uni_pass_len)
{
int pass_len = 0, i;
char *uni_pass;
if (password == NULL)
{
password = "";
}
uni_pass = (char *)malloc((strlen(password)+1)*2);
/* modify the password into a unicode version */
for (i = 0; i < (int)strlen(password); i++)
{
uni_pass[pass_len++] = 0;
uni_pass[pass_len++] = password[i];
}
uni_pass[pass_len++] = 0; /* null terminate */
uni_pass[pass_len++] = 0;
*uni_pass_len = pass_len;
return uni_pass;
}
/*
* Decrypt a pkcs8 block.
*/
static int p8_decrypt(const char *uni_pass, int uni_pass_len,
const uint8_t *salt, int iter,
uint8_t *priv_key, int priv_key_len, int id)
{
uint8_t p[BLOCK_SIZE*2];
uint8_t d[BLOCK_SIZE];
uint8_t Ai[SHA1_SIZE];
SHA1_CTX sha_ctx;
RC4_CTX rc4_ctx;
int i;
for (i = 0; i < BLOCK_SIZE; i++)
{
p[i] = salt[i % SALT_SIZE];
p[BLOCK_SIZE+i] = uni_pass[i % uni_pass_len];
d[i] = id;
}
/* get the key - no IV since we are using RC4 */
SHA1Init(&sha_ctx);
SHA1Update(&sha_ctx, d, sizeof(d));
SHA1Update(&sha_ctx, p, sizeof(p));
SHA1Final(&sha_ctx, Ai);
for (i = 1; i < iter; i++)
{
SHA1Init(&sha_ctx);
SHA1Update(&sha_ctx, Ai, SHA1_SIZE);
SHA1Final(&sha_ctx, Ai);
}
/* do the decryption */
if (id == PKCS12_KEY_ID)
{
RC4_setup(&rc4_ctx, Ai, 16);
RC4_crypt(&rc4_ctx, priv_key, priv_key, priv_key_len);
}
else /* MAC */
memcpy(priv_key, Ai, SHA1_SIZE);
return 0;
}
/*
* Take a raw pkcs12 block and the decrypt it and turn it into a certificate(s)
* and keys.
*/
int pkcs12_decode(SSL_CTX *ssl_ctx, SSLObjLoader *ssl_obj, const char *password)
{
uint8_t *buf = ssl_obj->buf;
int all_ok = 0, len, iterations, auth_safes_start,
auth_safes_end, auth_safes_len, key_offset, offset = 0;
int all_certs = 0;
uint8_t *version = NULL, *auth_safes = NULL, *cert, *orig_mac;
uint8_t key[SHA1_SIZE];
uint8_t mac[SHA1_SIZE];
const uint8_t *salt;
int uni_pass_len, ret;
int error_code = SSL_ERROR_NOT_SUPPORTED;
char *uni_pass = make_uni_pass(password, &uni_pass_len);
static const uint8_t pkcs_data[] = /* pkc7 data */
{ 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x01 };
static const uint8_t pkcs_encrypted[] = /* pkc7 encrypted */
{ 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x06 };
static const uint8_t pkcs8_key_bag[] = /* 1.2.840.113549.1.12.10.1.2 */
{ 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x0a, 0x01, 0x02 };
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0)
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: Invalid p12 ASN.1 file\n");
#endif
goto error;
}
if (asn1_get_int(buf, &offset, &version) < 0 || *version != 3)
{
error_code = SSL_ERROR_INVALID_VERSION;
goto error;
}
/* remove all the boring pcks7 bits */
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
len != sizeof(pkcs_data) ||
memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
goto error;
offset += len;
if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
asn1_next_obj(buf, &offset, ASN1_OCTET_STRING) < 0)
goto error;
/* work out the MAC start/end points (done on AuthSafes) */
auth_safes_start = offset;
auth_safes_end = offset;
if (asn1_skip_obj(buf, &auth_safes_end, ASN1_SEQUENCE) < 0)
goto error;
auth_safes_len = auth_safes_end - auth_safes_start;
auth_safes = malloc(auth_safes_len);
memcpy(auth_safes, &buf[auth_safes_start], auth_safes_len);
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
(len != sizeof(pkcs_encrypted) ||
memcmp(&buf[offset], pkcs_encrypted, sizeof(pkcs_encrypted))))
goto error;
offset += len;
if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(buf, &offset, ASN1_INTEGER) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
len != sizeof(pkcs_data) ||
memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
goto error;
offset += len;
/* work out the salt for the certificate */
if (get_pbe_params(buf, &offset, &salt, &iterations) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_IMPLICIT_TAG)) < 0)
goto error;
/* decrypt the certificate */
cert = &buf[offset];
if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations, cert,
len, PKCS12_KEY_ID)) < 0)
goto error;
offset += len;
/* load the certificate */
key_offset = 0;
all_certs = asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE);
/* keep going until all certs are loaded */
while (key_offset < all_certs)
{
int cert_offset = key_offset;
if (asn1_skip_obj(cert, &cert_offset, ASN1_SEQUENCE) < 0 ||
asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(cert, &key_offset, ASN1_OID) < 0 ||
asn1_next_obj(cert, &key_offset, ASN1_EXPLICIT_TAG) < 0 ||
asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(cert, &key_offset, ASN1_OID) < 0 ||
asn1_next_obj(cert, &key_offset, ASN1_EXPLICIT_TAG) < 0 ||
(len = asn1_next_obj(cert, &key_offset, ASN1_OCTET_STRING)) < 0)
goto error;
if ((ret = add_cert(ssl_ctx, &cert[key_offset], len)) < 0)
goto error;
key_offset = cert_offset;
}
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
len != sizeof(pkcs_data) ||
memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
goto error;
offset += len;
if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
asn1_next_obj(buf, &offset, ASN1_OCTET_STRING) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
(len != sizeof(pkcs8_key_bag)) ||
memcmp(&buf[offset], pkcs8_key_bag, sizeof(pkcs8_key_bag)))
goto error;
offset += len;
/* work out the salt for the private key */
if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
get_pbe_params(buf, &offset, &salt, &iterations) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
goto error;
/* decrypt the private key */
cert = &buf[offset];
if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations, cert,
len, PKCS12_KEY_ID)) < 0)
goto error;
offset += len;
/* load the private key */
if ((ret = p8_add_key(ssl_ctx, cert)) < 0)
goto error;
/* miss out on friendly name, local key id etc */
if (asn1_skip_obj(buf, &offset, ASN1_SET) < 0)
goto error;
/* work out the MAC */
if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0 ||
len != SHA1_SIZE)
goto error;
orig_mac = &buf[offset];
offset += len;
/* get the salt */
if ((len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0 || len != 8)
goto error;
salt = &buf[offset];
/* work out what the mac should be */
if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations,
key, SHA1_SIZE, PKCS12_MAC_ID)) < 0)
goto error;
hmac_sha1(auth_safes, auth_safes_len, key, SHA1_SIZE, mac);
if (memcmp(mac, orig_mac, SHA1_SIZE))
{
error_code = SSL_ERROR_INVALID_HMAC;
goto error;
}
all_ok = 1;
error:
free(version);
free(uni_pass);
free(auth_safes);
return all_ok ? SSL_OK : error_code;
}
/*
* Retrieve the salt/iteration details from a PBE block.
*/
static int get_pbe_params(uint8_t *buf, int *offset,
const uint8_t **salt, int *iterations)
{
static const uint8_t pbeSH1RC4[] = /* pbeWithSHAAnd128BitRC4 */
{ 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x01 };
int i, len;
uint8_t *iter = NULL;
int error_code = SSL_ERROR_NOT_SUPPORTED;
/* Get the PBE type */
if (asn1_next_obj(buf, offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, offset, ASN1_OID)) < 0)
goto error;
/* we expect pbeWithSHAAnd128BitRC4 (1.2.840.113549.1.12.1.1)
which is the only algorithm we support */
if (len != sizeof(pbeSH1RC4) ||
memcmp(&buf[*offset], pbeSH1RC4, sizeof(pbeSH1RC4)))
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: pkcs8/pkcs12 must use \"PBE-SHA1-RC4-128\"\n");
#endif
goto error;
}
*offset += len;
if (asn1_next_obj(buf, offset, ASN1_SEQUENCE) < 0 ||
(len = asn1_next_obj(buf, offset, ASN1_OCTET_STRING)) < 0 ||
len != 8)
goto error;
*salt = &buf[*offset];
*offset += len;
if ((len = asn1_get_int(buf, offset, &iter)) < 0)
goto error;
*iterations = 0;
for (i = 0; i < len; i++)
{
(*iterations) <<= 8;
(*iterations) += iter[i];
}
free(iter);
error_code = SSL_OK; /* got here - we are ok */
error:
return error_code;
}
#endif