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gnutls.c
1185 lines (1029 loc) · 32.1 KB
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gnutls.c
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/*
* OpenConnect (SSL + DTLS) VPN client
*
* Copyright © 2008-2012 Intel Corporation.
*
* Author: David Woodhouse <dwmw2@infradead.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* version 2.1, as published by the Free Software Foundation.
*
* 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
* 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:
*
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#include <gnutls/crypto.h>
#include <gnutls/pkcs12.h>
#ifdef HAVE_P11KIT
#include <p11-kit/p11-kit.h>
#include <p11-kit/pin.h>
static P11KitPin *pin_callback(const char *pin_source, P11KitUri *pin_uri,
const char *pin_description,
P11KitPinFlags flags,
void *_vpninfo);
#endif
#include "openconnect-internal.h"
/* Helper functions for reading/writing lines over SSL.
We could use cURL for the HTTP stuff, but it's overkill */
int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t len)
{
size_t orig_len = len;
while (len) {
int done = gnutls_record_send(vpninfo->https_sess, buf, len);
if (done > 0)
len -= done;
else if (done != GNUTLS_E_AGAIN) {
vpn_progress(vpninfo, PRG_ERR, _("Failed to write to SSL socket: %s"),
gnutls_strerror(done));
return -EIO;
} else {
fd_set wr_set, rd_set;
int maxfd = vpninfo->ssl_fd;
FD_ZERO(&wr_set);
FD_ZERO(&rd_set);
if (gnutls_record_get_direction(vpninfo->https_sess))
FD_SET(vpninfo->ssl_fd, &wr_set);
else
FD_SET(vpninfo->ssl_fd, &rd_set);
if (vpninfo->cancel_fd != -1) {
FD_SET(vpninfo->cancel_fd, &rd_set);
if (vpninfo->cancel_fd > vpninfo->ssl_fd)
maxfd = vpninfo->cancel_fd;
}
select(maxfd + 1, &rd_set, &wr_set, NULL, NULL);
if (vpninfo->cancel_fd != -1 &&
FD_ISSET(vpninfo->cancel_fd, &rd_set)) {
vpn_progress(vpninfo, PRG_ERR, _("SSL write cancelled\n"));
return -EINTR;
}
}
}
return orig_len;
}
int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len)
{
int done;
while ((done = gnutls_record_recv(vpninfo->https_sess, buf, len)) < 0) {
fd_set wr_set, rd_set;
int maxfd = vpninfo->ssl_fd;
if (done != GNUTLS_E_AGAIN) {
vpn_progress(vpninfo, PRG_ERR, _("Failed to read from SSL socket: %s"),
gnutls_strerror(done));
return -EIO;
} else {
FD_ZERO(&wr_set);
FD_ZERO(&rd_set);
if (gnutls_record_get_direction(vpninfo->https_sess))
FD_SET(vpninfo->ssl_fd, &wr_set);
else
FD_SET(vpninfo->ssl_fd, &rd_set);
if (vpninfo->cancel_fd != -1) {
FD_SET(vpninfo->cancel_fd, &rd_set);
if (vpninfo->cancel_fd > vpninfo->ssl_fd)
maxfd = vpninfo->cancel_fd;
}
select(maxfd + 1, &rd_set, &wr_set, NULL, NULL);
if (vpninfo->cancel_fd != -1 &&
FD_ISSET(vpninfo->cancel_fd, &rd_set)) {
vpn_progress(vpninfo, PRG_ERR, _("SSL read cancelled\n"));
return -EINTR;
}
}
}
return done;
}
int openconnect_SSL_gets(struct openconnect_info *vpninfo, char *buf, size_t len)
{
int i = 0;
int ret;
if (len < 2)
return -EINVAL;
while (1) {
ret = gnutls_record_recv(vpninfo->https_sess, buf + i, 1);
if (ret == 1) {
if (buf[i] == '\n') {
buf[i] = 0;
if (i && buf[i-1] == '\r') {
buf[i-1] = 0;
i--;
}
return i;
}
i++;
if (i >= len - 1) {
buf[i] = 0;
return i;
}
} else if (ret != GNUTLS_E_AGAIN) {
vpn_progress(vpninfo, PRG_ERR, _("Failed to read from SSL socket: %s\n"),
gnutls_strerror(ret));
ret = -EIO;
break;
} else {
fd_set rd_set, wr_set;
int maxfd = vpninfo->ssl_fd;
FD_ZERO(&rd_set);
FD_ZERO(&wr_set);
if (gnutls_record_get_direction(vpninfo->https_sess))
FD_SET(vpninfo->ssl_fd, &wr_set);
else
FD_SET(vpninfo->ssl_fd, &rd_set);
if (vpninfo->cancel_fd != -1) {
FD_SET(vpninfo->cancel_fd, &rd_set);
if (vpninfo->cancel_fd > vpninfo->ssl_fd)
maxfd = vpninfo->cancel_fd;
}
select(maxfd + 1, &rd_set, &wr_set, NULL, NULL);
if (vpninfo->cancel_fd != -1 &&
FD_ISSET(vpninfo->cancel_fd, &rd_set)) {
vpn_progress(vpninfo, PRG_ERR, _("SSL read cancelled\n"));
ret = -EINTR;
break;
}
}
}
buf[i] = 0;
return i ?: ret;
}
static int check_certificate_expiry(struct openconnect_info *vpninfo, gnutls_x509_crt_t cert)
{
const char *reason = NULL;
time_t expires = gnutls_x509_crt_get_expiration_time(cert);
time_t now = time(NULL);
if (expires == -1) {
vpn_progress(vpninfo, PRG_ERR,
_("Could not extract expiration time of certificate\n"));
return -EINVAL;
}
if (expires < now)
reason = _("Client certificate has expired at");
else if (expires < now + vpninfo->cert_expire_warning)
reason = _("Client certificate expires soon at");
if (reason) {
struct tm tm;
char buf[80];
gmtime_r(&expires, &tm);
strftime(buf, 80, "%a, %d %b %Y %T %Z", &tm);
vpn_progress(vpninfo, PRG_ERR, "%s: %s\n", reason, buf);
}
return 0;
}
/* For systems that don't support O_CLOEXEC, just don't bother.
It's not open for long anyway. */
#ifndef O_CLOEXEC
#define O_CLOEXEC
#endif
static int load_datum(struct openconnect_info *vpninfo,
gnutls_datum_t *datum, const char *fname)
{
struct stat st;
int fd, err;
fd = open(fname, O_RDONLY|O_CLOEXEC);
if (fd == -1) {
err = errno;
vpn_progress(vpninfo, PRG_ERR,
_("Failed to open certificate file %s: %s\n"),
vpninfo->cert, strerror(err));
return -ENOENT;
}
if (fstat(fd, &st)) {
err = errno;
vpn_progress(vpninfo, PRG_ERR,
_("Failed to stat certificate file %s: %s\n"),
vpninfo->cert, strerror(err));
close(fd);
return -EIO;
}
datum->size = st.st_size;
datum->data = gnutls_malloc(st.st_size + 1);
if (!datum->data) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to allocate certificate buffer\n"));
close(fd);
return -ENOMEM;
}
errno = EAGAIN;
if (read(fd, datum->data, datum->size) != datum->size) {
err = errno;
vpn_progress(vpninfo, PRG_ERR,
_("Failed to read certificate into memory: %s\n"),
strerror(err));
close(fd);
gnutls_free(datum->data);
return -EIO;
}
datum->data[st.st_size] = 0;
close(fd);
return 0;
}
#ifndef HAVE_GNUTLS_PKCS12_SIMPLE_PARSE
/* If we're using a version of GnuTLS from before this was
exported, pull in our local copy. */
#include "gnutls_pkcs12.c"
#endif
/* A non-zero, non-error return to make load_certificate() continue and
interpreting the file as other types */
#define NOT_PKCS12 1
static int load_pkcs12_certificate(struct openconnect_info *vpninfo,
gnutls_datum_t *datum,
gnutls_x509_privkey_t *key,
gnutls_x509_crt_t **chain,
unsigned int *chain_len,
gnutls_x509_crt_t **extra_certs,
unsigned int *extra_certs_len,
gnutls_x509_crl_t *crl)
{
gnutls_pkcs12_t p12;
char *pass;
int err;
err = gnutls_pkcs12_init(&p12);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to setup PKCS#12 data structure: %s\n"),
gnutls_strerror(err));
return -EIO;
}
err = gnutls_pkcs12_import(p12, datum, GNUTLS_X509_FMT_DER, 0);
if (err) {
gnutls_pkcs12_deinit(p12);
if (vpninfo->cert_type == CERT_TYPE_UNKNOWN)
return NOT_PKCS12;
vpn_progress(vpninfo, PRG_ERR,
_("Failed to import PKCS#12 file: %s\n"),
gnutls_strerror(err));
return -EINVAL;
}
pass = vpninfo->cert_password;
while ((err = gnutls_pkcs12_verify_mac(p12, pass)) == GNUTLS_E_MAC_VERIFY_FAILED) {
if (pass)
vpn_progress(vpninfo, PRG_ERR,
_("Failed to decrypt PKCS#12 certificate file\n"));
free(pass);
vpninfo->cert_password = NULL;
err = request_passphrase(vpninfo, &pass,
_("Enter PKCS#12 pass phrase:"));
if (err) {
gnutls_pkcs12_deinit(p12);
return -EINVAL;
}
}
/* If it wasn't GNUTLS_E_MAC_VERIFY_FAILED, then the problem wasn't just a
bad password. Give up. */
if (err) {
int level = PRG_ERR;
int ret = -EINVAL;
gnutls_pkcs12_deinit(p12);
/* If the first attempt, and we didn't know for sure it was PKCS#12
anyway, bail out and try loading it as something different. */
if (pass == vpninfo->cert_password &&
vpninfo->cert_type == CERT_TYPE_UNKNOWN) {
/* Make it non-fatal... */
level = PRG_TRACE;
ret = NOT_PKCS12;
}
vpn_progress(vpninfo, level,
_("Failed to process PKCS#12 file: %s\n"),
gnutls_strerror(err));
return ret;
}
err = gnutls_pkcs12_simple_parse(p12, pass, key, chain, chain_len,
extra_certs, extra_certs_len, crl, 0);
gnutls_pkcs12_deinit(p12);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to load PKCS#12 certificate: %s\n"),
gnutls_strerror(err));
return -EINVAL;
}
return 0;
}
/* Older versions of GnuTLS didn't actually bother to check this, so we'll
do it for them. */
static int check_issuer_sanity(gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer)
{
#if GNUTLS_VERSION_NUMBER > 0x300014
return 0;
#else
unsigned char id1[512], id2[512];
size_t id1_size = 512, id2_size = 512;
int err;
err = gnutls_x509_crt_get_authority_key_id(cert, id1, &id1_size, NULL);
if (err)
return 0;
err = gnutls_x509_crt_get_subject_key_id(issuer, id2, &id2_size, NULL);
if (err)
return 0;
if (id1_size == id2_size && !memcmp(id1, id2, id1_size))
return 0;
/* EEP! */
return -EIO;
#endif
}
static int count_x509_certificates(gnutls_datum_t *datum)
{
int count = 0;
char *p = (char *)datum->data;
while (p) {
p = strstr(p, "-----BEGIN ");
if (!p)
break;
p += 11;
if (!strncmp(p, "CERTIFICATE", 11) ||
!strncmp(p, "X509 CERTIFICATE", 16))
count++;
}
return count;
}
static int load_certificate(struct openconnect_info *vpninfo)
{
gnutls_datum_t fdata;
gnutls_x509_privkey_t key = NULL;
gnutls_x509_crl_t crl = NULL;
gnutls_x509_crt_t last_cert, cert = NULL;
gnutls_x509_crt_t *extra_certs = NULL, *supporting_certs = NULL;
unsigned int nr_supporting_certs = 0, nr_extra_certs = 0;
unsigned int certs_to_free = 0; /* How many of supporting_certs */
int err; /* GnuTLS error */
int ret = 0; /* our error (zero or -errno) */
int i;
unsigned char key_id[20];
size_t key_id_size = sizeof(key_id);
if (vpninfo->cert_type == CERT_TYPE_TPM) {
vpn_progress(vpninfo, PRG_ERR,
_("TPM support not available with GnuTLS\n"));
return -EINVAL;
}
if (!strncmp(vpninfo->cert, "pkcs11:", 7)) {
char *cert_url = (char *)vpninfo->cert;
char *key_url = (char *)vpninfo->sslkey;
#ifdef HAVE_P11KIT
char pin_source[40];
P11KitUri *uri;
sprintf(pin_source, "openconnect:%p", vpninfo);
uri = p11_kit_uri_new();
if (p11_kit_uri_parse(vpninfo->cert, P11_KIT_URI_FOR_OBJECT, uri) != P11_KIT_URI_OK) {
vpn_progress(vpninfo, PRG_ERR, _("Failed to parse PKCS#11 URL '%s'\n"),
vpninfo->cert);
p11_kit_uri_free(uri);
return -EINVAL;
}
if (!p11_kit_uri_get_pin_source(uri)) {
p11_kit_uri_set_pin_source(uri, pin_source);
p11_kit_uri_format(uri, P11_KIT_URI_FOR_OBJECT, &cert_url);
}
if (p11_kit_uri_parse(vpninfo->sslkey, P11_KIT_URI_FOR_OBJECT, uri) != P11_KIT_URI_OK) {
vpn_progress(vpninfo, PRG_ERR, _("Failed to parse PKCS#11 URL '%s'\n"),
vpninfo->sslkey);
p11_kit_uri_free(uri);
free(cert_url);
return -EINVAL;
}
if (!p11_kit_uri_get_pin_source(uri)) {
p11_kit_uri_set_pin_source(uri, pin_source);
p11_kit_uri_format(uri, P11_KIT_URI_FOR_OBJECT, &key_url);
}
p11_kit_uri_free(uri);
p11_kit_pin_register_callback(pin_source, pin_callback, vpninfo, NULL);
#endif
vpn_progress(vpninfo, PRG_TRACE,
_("Using PKCS#11 certificate %s\n"), vpninfo->cert);
err = gnutls_certificate_set_x509_key_file(vpninfo->https_cred,
cert_url, key_url,
GNUTLS_X509_FMT_PEM);
if (cert_url != vpninfo->cert)
free(cert_url);
if (key_url != vpninfo->sslkey)
free(key_url);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Error loading PKCS#11 certificate: %s\n"),
gnutls_strerror(err));
return -EIO;
}
return 0;
}
vpn_progress(vpninfo, PRG_TRACE,
_("Using certificate file %s\n"), vpninfo->cert);
ret = load_datum(vpninfo, &fdata, vpninfo->cert);
if (ret)
return ret;
if (vpninfo->cert_type == CERT_TYPE_PKCS12 ||
vpninfo->cert_type == CERT_TYPE_UNKNOWN) {
ret = load_pkcs12_certificate(vpninfo, &fdata, &key,
&supporting_certs, &nr_supporting_certs,
&extra_certs, &nr_extra_certs,
&crl);
if (ret < 0)
goto out;
else if (!ret) {
if (nr_supporting_certs) {
cert = supporting_certs[0];
goto got_cert;
}
vpn_progress(vpninfo, PRG_ERR,
_("PKCS#11 file contained no certificate\n"));
ret = -EINVAL;
goto out;
}
/* It returned NOT_PKCS12.
Fall through to try PEM formats. */
}
/* We need to know how many there are in *advance*; it won't just allocate
the array for us :( */
nr_extra_certs = count_x509_certificates(&fdata);
if (!nr_extra_certs)
nr_extra_certs = 1; /* wtf? Oh well, we'll fail later... */
extra_certs = calloc(nr_extra_certs, sizeof(cert));
if (!extra_certs) {
nr_extra_certs = 0;
ret = -ENOMEM;
goto out;
}
err = gnutls_x509_crt_list_import(extra_certs, &nr_extra_certs, &fdata,
GNUTLS_X509_FMT_PEM, 0);
if (err <= 0) {
const char *reason;
if (!err || err == GNUTLS_E_NO_CERTIFICATE_FOUND)
reason = _("No certificate found in file");
else
reason = gnutls_strerror(err);
vpn_progress(vpninfo, PRG_ERR,
_("Loading certificate failed: %s\n"),
reason);
ret = -EINVAL;
goto out;
}
nr_extra_certs = err;
err = 0;
if (vpninfo->sslkey != vpninfo->cert) {
gnutls_free(fdata.data);
vpn_progress(vpninfo, PRG_TRACE,
_("Using private key file %s\n"), vpninfo->cert);
ret = load_datum(vpninfo, &fdata, vpninfo->sslkey);
if (ret)
goto out;
}
gnutls_x509_privkey_init(&key);
/* Try PKCS#1 (and PKCS#8 without password) first. GnuTLS doesn't
support OpenSSL's old PKCS#1-based encrypted format. We should
probably check for it and give a more coherent failure mode. */
err = gnutls_x509_privkey_import(key, &fdata, GNUTLS_X509_FMT_PEM);
if (err) {
/* If that fails, try PKCS#8 */
char *pass = vpninfo->cert_password;
/* Yay, just for fun this is *different* to PKCS#12. Where we could
try an empty password there, in this case the empty-password case
has already been *tried* by gnutls_x509_privkey_import(). If we
just call gnutls_x509_privkey_import_pkcs8() with a NULL password,
it'll SEGV. You have to set the GNUTLS_PKCS_PLAIN flag if you want
to try without a password. Passing NULL evidently isn't enough of
a hint. And in GnuTLS 3.1 where that crash has been fixed, passing
NULL will cause it to return GNUTLS_E_ENCRYPTED_STRUCTURE (a new
error code) rather than GNUTLS_E_DECRYPTION_FAILED. So just pass ""
instead of NULL, and don't worry about either case. */
while ((err = gnutls_x509_privkey_import_pkcs8(key, &fdata,
GNUTLS_X509_FMT_PEM,
pass?pass:"", 0))) {
if (err != GNUTLS_E_DECRYPTION_FAILED) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to load private key as PKCS#8: %s\n"),
gnutls_strerror(err));
ret = -EINVAL;
goto out;
}
if (pass) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to decrypt PKCS#8 certificate file\n"));
free (pass);
}
err = request_passphrase(vpninfo, &pass,
_("Enter PEM pass phrase:"));
if (err) {
ret = -EINVAL;
goto out;
}
}
}
err = gnutls_x509_privkey_get_key_id(key, 0, key_id, &key_id_size);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to get key ID: %s\n"),
gnutls_strerror(err));
goto out;
}
for (i = 0; i < nr_extra_certs; i++) {
unsigned char cert_id[20];
size_t cert_id_size = sizeof(cert_id);
err = gnutls_x509_crt_get_key_id(extra_certs[i], 0, cert_id, &cert_id_size);
if (err)
continue;
if (cert_id_size == key_id_size && !memcmp(cert_id, key_id, key_id_size)) {
cert = extra_certs[i];
/* Move the rest of the array down */
for (; i < nr_extra_certs - 1; i++)
extra_certs[i] = extra_certs[i+1];
nr_extra_certs--;
goto got_cert;
}
}
/* We shouldn't reach this. It means that we didn't find *any* matching cert */
vpn_progress(vpninfo, PRG_ERR,
_("No SSL certificate found to match private key\n"));
ret = -EINVAL;
goto out;
got_cert:
check_certificate_expiry(vpninfo, cert);
if (crl) {
err = gnutls_certificate_set_x509_crl(vpninfo->https_cred, &crl, 1);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Setting certificate recovation list failed: %s\n"),
gnutls_strerror(err));
goto out;
}
}
/* OpenSSL has problems with certificate chains — if there are
multiple certs with the same name, it doesn't necessarily
choose the _right_ one. (RT#1942)
Pick the right ones for ourselves and add them manually. */
if (nr_supporting_certs) {
/* We already got a bunch of certs from PKCS#12 file.
Remember how many need to be freed when we're done,
since we'll expand the supporting_certs array with
more from the cafile if we can. */
last_cert = supporting_certs[nr_supporting_certs-1];
certs_to_free = nr_supporting_certs;
} else {
last_cert = cert;
certs_to_free = nr_supporting_certs = 1;
}
while (1) {
gnutls_x509_crt_t issuer;
for (i = 0; i < nr_extra_certs; i++) {
if (gnutls_x509_crt_check_issuer(last_cert, extra_certs[i]) &&
!check_issuer_sanity(last_cert, extra_certs[i]))
break;
}
if (i < nr_extra_certs) {
issuer = extra_certs[i];
} else {
err = gnutls_certificate_get_issuer(vpninfo->https_cred,
last_cert, &issuer, 0);
if (err)
break;
}
/* The check_issuer_sanity() function works fine as a workaround where
it was used above, but when gnutls_certificate_get_issuer() returns
a bogus cert, there's nothing we can do to fix it up. We don't get
to iterate over all the available certs like we can over our own
list. */
if (check_issuer_sanity(last_cert, issuer)) {
/* Hm, is there a bug reference for this? Or just the git commit
reference (c1ef7efb in master, 5196786c in gnutls_3_0_x-2)? */
vpn_progress(vpninfo, PRG_ERR,
_("WARNING: GnuTLS returned incorrect issuer certs; authentication may fail!\n"));
break;
}
if (issuer == last_cert) {
/* Don't actually include the root CA. If they don't already trust it,
then handing it to them isn't going to help. But don't omit the
original certificate if it's self-signed. */
if (nr_supporting_certs > 1)
nr_supporting_certs--;
break;
}
/* OK, we found a new cert to add to our chain. */
supporting_certs = gnutls_realloc(supporting_certs,
sizeof(cert) * ++nr_supporting_certs);
if (!supporting_certs) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to allocate memory for supporting certificates\n"));
/* The world is probably about to end, but try without them anyway */
certs_to_free = 0;
ret = -ENOMEM;
goto out;
}
/* First time we actually allocated an array? Copy the first cert into it */
if (nr_supporting_certs == 2)
supporting_certs[0] = cert;
/* Append the new one */
supporting_certs[nr_supporting_certs-1] = issuer;
last_cert = issuer;
}
for (i = 1; i < nr_supporting_certs; i++) {
char name[80];
size_t namelen;
sprintf(name, "<unknown>");
namelen = sizeof(name);
if (gnutls_x509_crt_get_dn_by_oid(supporting_certs[i],
GNUTLS_OID_X520_COMMON_NAME,
0, 0, name, &namelen) &&
gnutls_x509_crt_get_dn(supporting_certs[i], name, &namelen))
sprintf(name, "<unknown>");
vpn_progress(vpninfo, PRG_DEBUG,
_("Adding supporting CA '%s'\n"), name);
}
err = gnutls_certificate_set_x509_key(vpninfo->https_cred,
supporting_certs ? supporting_certs : &cert,
supporting_certs ? 1 : nr_supporting_certs,
key);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Setting certificate failed: %s\n"),
gnutls_strerror(err));
ret = -EIO;
}
out:
if (crl)
gnutls_x509_crl_deinit(crl);
if (key)
gnutls_x509_privkey_deinit(key);
if (cert)
gnutls_x509_crt_deinit(cert);
/* From 1 because cert is the first one (and might exist
even if supporting_certs is NULL) */
for (i = 1; i < certs_to_free; i++) {
if (supporting_certs[i])
gnutls_x509_crt_deinit(supporting_certs[i]);
}
for (i = 0; i < nr_extra_certs; i++) {
if (extra_certs[i])
gnutls_x509_crt_deinit(extra_certs[i]);
}
gnutls_free(extra_certs);
gnutls_free(supporting_certs);
gnutls_free(fdata.data);
return ret;
}
static int get_cert_fingerprint(struct openconnect_info *vpninfo,
gnutls_x509_crt_t cert,
gnutls_digest_algorithm_t algo,
char *buf)
{
unsigned char md[256];
size_t md_size = sizeof(md);
unsigned int i;
if (gnutls_x509_crt_get_fingerprint(cert, algo, md, &md_size))
return -EIO;
for (i=0; i < md_size; i++)
sprintf(&buf[i*2], "%02X", md[i]);
return 0;
}
int get_cert_md5_fingerprint(struct openconnect_info *vpninfo,
OPENCONNECT_X509 *cert, char *buf)
{
return get_cert_fingerprint(vpninfo, cert, GNUTLS_DIG_MD5, buf);
}
int openconnect_get_cert_sha1(struct openconnect_info *vpninfo,
OPENCONNECT_X509 *cert, char *buf)
{
return get_cert_fingerprint(vpninfo, cert, GNUTLS_DIG_SHA1, buf);
}
char *openconnect_get_cert_details(struct openconnect_info *vpninfo,
OPENCONNECT_X509 *cert)
{
gnutls_datum_t buf;
char *ret;
if (gnutls_x509_crt_print(cert, GNUTLS_CRT_PRINT_FULL, &buf))
return NULL;
/* Just in case gnutls_free() isn't free(), we can't steal it. */
ret = strdup((char *)buf.data);
gnutls_free(buf.data);
return ret;
}
int openconnect_get_cert_DER(struct openconnect_info *vpninfo,
OPENCONNECT_X509 *cert, unsigned char **buf)
{
size_t l = 0;
unsigned char *ret = NULL;
if (gnutls_x509_crt_export(cert, GNUTLS_X509_FMT_DER, ret, &l) !=
GNUTLS_E_SHORT_MEMORY_BUFFER)
return -EIO;
ret = malloc(l);
if (!ret)
return -ENOMEM;
if (gnutls_x509_crt_export(cert, GNUTLS_X509_FMT_DER, ret, &l)) {
free(ret);
return -EIO;
}
*buf = ret;
return l;
}
static int verify_peer(gnutls_session_t session)
{
struct openconnect_info *vpninfo = gnutls_session_get_ptr(session);
const gnutls_datum_t *cert_list;
gnutls_x509_crt_t cert;
unsigned int status, cert_list_size;
const char *reason = NULL;
int err;
if (vpninfo->peer_cert) {
gnutls_x509_crt_deinit(vpninfo->peer_cert);
vpninfo->peer_cert = NULL;
}
cert_list = gnutls_certificate_get_peers (session, &cert_list_size);
if (!cert_list) {
vpn_progress(vpninfo, PRG_ERR, _("Server presented no certificate\n"));
return GNUTLS_E_CERTIFICATE_ERROR;
}
if (vpninfo->servercert) {
unsigned char sha1bin[SHA1_SIZE];
char fingerprint[(SHA1_SIZE * 2) + 1];
int i;
err = openconnect_sha1(sha1bin, cert_list[0].data, cert_list[0].size);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Could not calculate SHA1 of server's certificate\n"));
return GNUTLS_E_CERTIFICATE_ERROR;
}
for (i=0; i < SHA1_SIZE; i++)
sprintf(&fingerprint[i*2], "%02X", sha1bin[i]);
if (strcasecmp(vpninfo->servercert, fingerprint)) {
vpn_progress(vpninfo, PRG_ERR,
_("Server SSL certificate didn't match: %s\n"), fingerprint);
return GNUTLS_E_CERTIFICATE_ERROR;
}
return 0;
}
err = gnutls_certificate_verify_peers2 (session, &status);
if (err) {
vpn_progress(vpninfo, PRG_ERR, _("Error checking server cert status\n"));
return GNUTLS_E_CERTIFICATE_ERROR;
}
if (status & GNUTLS_CERT_REVOKED)
reason = _("certificate revoked");
else if (status & GNUTLS_CERT_SIGNER_NOT_FOUND)
reason = _("signer not found");
else if (status & GNUTLS_CERT_SIGNER_NOT_CA)
reason = _("signer not a CA certificate");
else if (status & GNUTLS_CERT_INSECURE_ALGORITHM)
reason = _("insecure algorithm");
else if (status & GNUTLS_CERT_NOT_ACTIVATED)
reason = _("certificate not yet activated");
else if (status & GNUTLS_CERT_EXPIRED)
reason = _("certificate expired");
else if (status & GNUTLS_CERT_INVALID)
/* If this is set and no other reason, it apparently means
that signature verification failed. Not entirely sure
why we don't just set a bit for that too. */
reason = _("signature verification failed");
err = gnutls_x509_crt_init(&cert);
if (err) {
vpn_progress(vpninfo, PRG_ERR, _("Error initialising X509 cert structure\n"));
return GNUTLS_E_CERTIFICATE_ERROR;
}
err = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
if (err) {
vpn_progress(vpninfo, PRG_ERR, _("Error importing server's cert\n"));
gnutls_x509_crt_deinit(cert);
return GNUTLS_E_CERTIFICATE_ERROR;
}
if (!reason && !gnutls_x509_crt_check_hostname(cert, vpninfo->hostname))
reason = _("certificate does not match hostname");
if (reason) {
vpn_progress(vpninfo, PRG_INFO, "Server certificate verify failed: %s\n",
reason);
if (vpninfo->validate_peer_cert)
err = vpninfo->validate_peer_cert(vpninfo->cbdata,
cert,
reason) ? GNUTLS_E_CERTIFICATE_ERROR : 0;
else
err = GNUTLS_E_CERTIFICATE_ERROR;
}
vpninfo->peer_cert = cert;
return err;
}
int openconnect_open_https(struct openconnect_info *vpninfo)
{
int ssl_sock = -1;
int err;
if (vpninfo->https_sess)
return 0;
ssl_sock = connect_https_socket(vpninfo);
if (ssl_sock < 0)
return ssl_sock;
if (!vpninfo->https_cred) {
gnutls_certificate_allocate_credentials(&vpninfo->https_cred);
gnutls_certificate_set_x509_trust_file(vpninfo->https_cred,
"/etc/pki/tls/certs/ca-bundle.crt",
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_verify_function (vpninfo->https_cred,
verify_peer);
/* FIXME: Ensure TLSv1.0, no options */
if (vpninfo->cafile) {
err = gnutls_certificate_set_x509_trust_file(vpninfo->https_cred,
vpninfo->cafile,
GNUTLS_X509_FMT_PEM);
if (err < 0) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to open CA file '%s': %s\n"),
vpninfo->cafile, gnutls_strerror(err));
close(ssl_sock);
return -EINVAL;
}
}
if (vpninfo->cert) {
err = load_certificate(vpninfo);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Loading certificate failed. Aborting.\n"));
return err;
}
}
/* We just want to do:
SSL_CTX_set_purpose(vpninfo->https_ctx, X509_PURPOSE_ANY);
... but it doesn't work with OpenSSL < 0.9.8k because of
problems with inheritance (fixed in v1.1.4.6 of
crypto/x509/x509_vpm.c) so we have to play silly buggers
instead. This trick doesn't work _either_ in < 0.9.7 but
I don't know of _any_ workaround which will, and can't
be bothered to find out either. */
}
gnutls_init (&vpninfo->https_sess, GNUTLS_CLIENT);
gnutls_session_set_ptr (vpninfo->https_sess, (void *) vpninfo);
err = gnutls_priority_set_direct (vpninfo->https_sess, "NONE:+VERS-TLS1.0:+SHA1:+AES-128-CBC:+RSA:+COMP-NULL:%COMPAT:%DISABLE_SAFE_RENEGOTIATION", NULL);
if (err) {
vpn_progress(vpninfo, PRG_ERR,
_("Failed to set TLS priority string: %s\n"),
gnutls_strerror(err));
return -EIO;
}