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/* $Id: certproc.c,v 1.7 2016/09/13 17:13:37 deraadt Exp $ */
/*
* Copyright (c) 2016 Kristaps Dzonsons <kristaps@bsd.lv>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <openssl/pem.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/err.h>
#include "extern.h"
#define MARKER "-----BEGIN CERTIFICATE-----"
/*
* Convert an X509 certificate to a buffer of "sz".
* We don't guarantee that it's nil-terminated.
* Returns NULL on failure.
*/
static char *
x509buf(X509 *x, size_t *sz)
{
BIO *bio;
char *p;
int ssz;
/* Convert X509 to PEM in BIO. */
if (NULL == (bio = BIO_new(BIO_s_mem()))) {
warnx("BIO_new");
return (NULL);
} else if (!PEM_write_bio_X509(bio, x)) {
warnx("PEM_write_bio_X509");
BIO_free(bio);
return (NULL);
}
/*
* Now convert bio to string.
* Make into nil-terminated, just in case.
*/
if (NULL == (p = calloc(1, bio->num_write + 1))) {
warn("calloc");
BIO_free(bio);
return (NULL);
}
ssz = BIO_read(bio, p, bio->num_write);
if (ssz < 0 || (unsigned)ssz != bio->num_write) {
warnx("BIO_read");
BIO_free(bio);
return (NULL);
}
*sz = ssz;
BIO_free(bio);
return (p);
}
int
certproc(int netsock, int filesock)
{
char *csr = NULL, *chain = NULL, *url = NULL;
unsigned char *csrcp, *chaincp;
size_t csrsz, chainsz;
int i, rc = 0, idx = -1, cc;
enum certop op;
long lval;
X509 *x = NULL, *chainx = NULL;
X509_EXTENSION *ext = NULL;
X509V3_EXT_METHOD *method = NULL;
void *entries;
STACK_OF(CONF_VALUE) *val;
CONF_VALUE *nval;
/* File-system and sandbox jailing. */
ERR_load_crypto_strings();
if (pledge("stdio", NULL) == -1) {
warn("pledge");
goto out;
}
/* Read what the netproc wants us to do. */
op = CERT__MAX;
if (0 == (lval = readop(netsock, COMM_CSR_OP)))
op = CERT_STOP;
else if (CERT_REVOKE == lval || CERT_UPDATE == lval)
op = lval;
if (CERT_STOP == op) {
rc = 1;
goto out;
} else if (CERT__MAX == op) {
warnx("unknown operation from netproc");
goto out;
}
/*
* Pass revocation right through to fileproc.
* If the reader is terminated, ignore it.
*/
if (CERT_REVOKE == op) {
if (writeop(filesock, COMM_CHAIN_OP, FILE_REMOVE) >= 0)
rc = 1;
goto out;
}
/*
* Wait until we receive the DER encoded (signed) certificate
* from the network process.
* Then convert the DER encoding into an X509 certificate.
*/
if (NULL == (csr = readbuf(netsock, COMM_CSR, &csrsz)))
goto out;
csrcp = (u_char *)csr;
x = d2i_X509(NULL, (const u_char **)&csrcp, csrsz);
if (NULL == x) {
warnx("d2i_X509");
goto out;
}
/*
* Extract the CA Issuers from its NID.
* TODO: I have no idea what I'm doing.
*/
idx = X509_get_ext_by_NID(x, NID_info_access, idx);
if (idx >= 0 && NULL != (ext = X509_get_ext(x, idx)))
method = (X509V3_EXT_METHOD *)X509V3_EXT_get(ext);
entries = X509_get_ext_d2i(x, NID_info_access, 0, 0);
if (NULL != method && NULL != entries) {
val = method->i2v(method, entries, 0);
for (i = 0; i < sk_CONF_VALUE_num(val); i++) {
nval = sk_CONF_VALUE_value(val, i);
if (strcmp(nval->name, "CA Issuers - URI"))
continue;
url = strdup(nval->value);
if (NULL == url) {
warn("strdup");
goto out;
}
break;
}
}
if (NULL == url) {
warnx("no CA issuer registered with certificate");
goto out;
}
/* Write the CA issuer to the netsock. */
if (writestr(netsock, COMM_ISSUER, url) <= 0)
goto out;
/* Read the full-chain back from the netsock. */
if (NULL == (chain = readbuf(netsock, COMM_CHAIN, &chainsz)))
goto out;
/*
* Then check if the chain is PEM-encoded by looking to see if
* it begins with the PEM marker.
* If so, ship it as-is; otherwise, convert to a PEM encoded
* buffer and ship that.
* FIXME: if PEM, re-parse it.
*/
if (chainsz <= strlen(MARKER) ||
strncmp(chain, MARKER, strlen(MARKER))) {
chaincp = (u_char *)chain;
chainx = d2i_X509(NULL, (const u_char **)&chaincp, chainsz);
if (NULL == chainx) {
warnx("d2i_X509");
goto out;
}
free(chain);
if (NULL == (chain = x509buf(chainx, &chainsz)))
goto out;
}
/* Allow reader termination to just push us out. */
if (0 == (cc = writeop(filesock, COMM_CHAIN_OP, FILE_CREATE)))
rc = 1;
if (cc <= 0)
goto out;
if (0 == (cc = writebuf(filesock, COMM_CHAIN, chain, chainsz)))
rc = 1;
if (cc <= 0)
goto out;
/*
* Next, convert the X509 to a buffer and send that.
* Reader failure doesn't change anything.
*/
free(chain);
if (NULL == (chain = x509buf(x, &chainsz)))
goto out;
if (writebuf(filesock, COMM_CSR, chain, chainsz) < 0)
goto out;
rc = 1;
out:
close(netsock);
close(filesock);
if (NULL != x)
X509_free(x);
if (NULL != chainx)
X509_free(chainx);
free(csr);
free(url);
free(chain);
ERR_print_errors_fp(stderr);
ERR_free_strings();
return (rc);
}
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