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/*
SSSD - certificate handling utils - openssl version
Copyright (C) Sumit Bose <sbose@redhat.com> 2015
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <openssl/x509.h>
#include <openssl/bio.h>
#include <openssl/pem.h>
#include "util/util.h"
errno_t sss_cert_der_to_pem(TALLOC_CTX *mem_ctx, const uint8_t *der_blob,
size_t der_size, char **pem, size_t *pem_size)
{
X509 *x509 = NULL;
BIO *bio_mem = NULL;
const unsigned char *d;
int ret;
long p_size;
char *p;
if (der_blob == NULL || der_size == 0) {
return EINVAL;
}
d = (const unsigned char *) der_blob;
x509 = d2i_X509(NULL, &d, (int) der_size);
if (x509 == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "d2i_X509 failed.\n");
return EINVAL;
}
bio_mem = BIO_new(BIO_s_mem());
if (bio_mem == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "BIO_new failed.\n");
ret = ENOMEM;
goto done;
}
ret = PEM_write_bio_X509(bio_mem, x509);
if (ret != 1) {
DEBUG(SSSDBG_OP_FAILURE, "PEM_write_bio_X509 failed.\n");
ret = EIO;
goto done;
}
p_size = BIO_get_mem_data(bio_mem, &p);
if (p_size == 0) {
DEBUG(SSSDBG_OP_FAILURE, "Unexpected PEM size [%ld].\n", p_size);
ret = EINVAL;
goto done;
}
if (pem != NULL) {
*pem = talloc_strndup(mem_ctx, p, p_size);
if (*pem == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "talloc_memdup failed.\n");
ret = ENOMEM;
goto done;
}
}
if (pem_size != NULL) {
*pem_size = p_size;
}
ret = EOK;
done:
X509_free(x509);
BIO_free_all(bio_mem);
return ret;
}
errno_t sss_cert_pem_to_der(TALLOC_CTX *mem_ctx, const char *pem,
uint8_t **_der_blob, size_t *_der_size)
{
X509 *x509 = NULL;
BIO *bio_mem = NULL;
int ret;
unsigned char *buf;
int buf_size;
uint8_t *der_blob;
size_t der_size;
if (pem == NULL) {
return EINVAL;
}
bio_mem = BIO_new(BIO_s_mem());
if (bio_mem == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "BIO_new failed.\n");
ret = ENOMEM;
goto done;
}
ret = BIO_puts(bio_mem, pem);
if (ret <= 0) {
DEBUG(SSSDBG_OP_FAILURE, "BIO_puts failed.\n");
ret = EIO;
goto done;
}
x509 = PEM_read_bio_X509(bio_mem, NULL, NULL, NULL);
if (x509 == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "PEM_read_bio_X509 failed.\n");
ret = EIO;
goto done;
}
buf_size = i2d_X509(x509, NULL);
if (buf_size <= 0) {
DEBUG(SSSDBG_OP_FAILURE, "i2d_X509 failed.\n");
ret = EIO;
goto done;
}
if (_der_blob != NULL) {
buf = talloc_size(mem_ctx, buf_size);
if (buf == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "talloc_size failed.\n");
ret = ENOMEM;
goto done;
}
der_blob = buf;
der_size = i2d_X509(x509, &buf);
if (der_size != buf_size) {
talloc_free(der_blob);
DEBUG(SSSDBG_CRIT_FAILURE,
"i2d_X509 size mismatch between two calls.\n");
ret = EIO;
goto done;
}
*_der_blob = der_blob;
}
if (_der_size != NULL) {
*_der_size = buf_size;
}
ret = EOK;
done:
X509_free(x509);
BIO_free_all(bio_mem);
return ret;
}
#define SSH_RSA_HEADER "ssh-rsa"
#define SSH_RSA_HEADER_LEN (sizeof(SSH_RSA_HEADER) - 1)
errno_t cert_to_ssh_key(TALLOC_CTX *mem_ctx, const char *ca_db,
const uint8_t *der_blob, size_t der_size,
uint8_t **key, size_t *key_size)
{
int ret;
size_t size;
const unsigned char *d;
uint8_t *buf = NULL;
size_t c;
X509 *cert = NULL;
EVP_PKEY *cert_pub_key = NULL;
int modulus_len;
unsigned char modulus[OPENSSL_RSA_MAX_MODULUS_BITS/8];
int exponent_len;
unsigned char exponent[OPENSSL_RSA_MAX_PUBEXP_BITS/8];
if (der_blob == NULL || der_size == 0) {
return EINVAL;
}
d = (const unsigned char *) der_blob;
cert = d2i_X509(NULL, &d, (int) der_size);
if (cert == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "d2i_X509 failed.\n");
return EINVAL;
}
/* TODO: verify certificate !!!!! */
cert_pub_key = X509_get_pubkey(cert);
if (cert_pub_key == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "X509_get_pubkey failed.\n");
ret = EIO;
goto done;
}
if (cert_pub_key->type != EVP_PKEY_RSA) {
DEBUG(SSSDBG_CRIT_FAILURE,
"Expected RSA public key, found unsupported [%d].\n",
cert_pub_key->type);
ret = EINVAL;
goto done;
}
modulus_len = BN_bn2bin(cert_pub_key->pkey.rsa->n, modulus);
exponent_len = BN_bn2bin(cert_pub_key->pkey.rsa->e, exponent);
size = SSH_RSA_HEADER_LEN + 3 * sizeof(uint32_t)
+ modulus_len
+ exponent_len
+ 1; /* see comment about missing 00 below */
buf = talloc_size(mem_ctx, size);
if (buf == NULL) {
DEBUG(SSSDBG_OP_FAILURE, "talloc_size failed.\n");
ret = ENOMEM;
goto done;
}
c = 0;
SAFEALIGN_SET_UINT32(buf, htobe32(SSH_RSA_HEADER_LEN), &c);
safealign_memcpy(&buf[c], SSH_RSA_HEADER, SSH_RSA_HEADER_LEN, &c);
SAFEALIGN_SET_UINT32(&buf[c], htobe32(exponent_len), &c);
safealign_memcpy(&buf[c], exponent, exponent_len, &c);
/* Adding missing 00 which afaik is added to make sure
* the bigint is handled as positive number */
/* TODO: make a better check if 00 must be added or not, e.g. ... & 0x80)
*/
SAFEALIGN_SET_UINT32(&buf[c], htobe32(modulus_len + 1), &c);
SAFEALIGN_SETMEM_VALUE(&buf[c], '\0', unsigned char, &c);
safealign_memcpy(&buf[c], modulus, modulus_len, &c);
*key = buf;
*key_size = size;
ret = EOK;
done:
if (ret != EOK) {
talloc_free(buf);
}
EVP_PKEY_free(cert_pub_key);
X509_free(cert);
return ret;
}
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