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/***
This file is part of systemd.
Copyright 2012 Lennart Poettering
Copyright 2012 Zbigniew Jędrzejewski-Szmek
systemd 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.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_GNUTLS
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#endif
#include "systemd-basic/alloc-util.h"
#include "systemd-basic/log.h"
#include "systemd-basic/macro.h"
#include "systemd-basic/string-util.h"
#include "systemd-basic/strv.h"
#include "systemd-basic/util.h"
#include "systemd-microhttpd/microhttpd-util.h"
void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
char *f;
f = strjoina("microhttpd: ", fmt);
DISABLE_WARNING_FORMAT_NONLITERAL;
log_internalv(LOG_INFO, 0, NULL, 0, NULL, f, ap);
REENABLE_WARNING;
}
static int mhd_respond_internal(struct MHD_Connection *connection,
enum MHD_RequestTerminationCode code,
char *buffer,
size_t size,
enum MHD_ResponseMemoryMode mode) {
struct MHD_Response *response;
int r;
assert(connection);
response = MHD_create_response_from_buffer(size, buffer, mode);
if (!response)
return MHD_NO;
log_debug("Queueing response %u: %s", code, buffer);
MHD_add_response_header(response, "Content-Type", "text/plain");
r = MHD_queue_response(connection, code, response);
MHD_destroy_response(response);
return r;
}
int mhd_respond(struct MHD_Connection *connection,
enum MHD_RequestTerminationCode code,
const char *message) {
return mhd_respond_internal(connection, code,
(char*) message, strlen(message),
MHD_RESPMEM_PERSISTENT);
}
int mhd_respond_oom(struct MHD_Connection *connection) {
return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE, "Out of memory.\n");
}
int mhd_respondf(struct MHD_Connection *connection,
enum MHD_RequestTerminationCode code,
const char *format, ...) {
char *m;
int r;
va_list ap;
assert(connection);
assert(format);
va_start(ap, format);
r = vasprintf(&m, format, ap);
va_end(ap);
if (r < 0)
return respond_oom(connection);
return mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
}
#ifdef HAVE_GNUTLS
static struct {
const char *const names[4];
int level;
bool enabled;
} gnutls_log_map[] = {
{ {"0"}, LOG_DEBUG },
{ {"1", "audit"}, LOG_WARNING, true}, /* gnutls session audit */
{ {"2", "assert"}, LOG_DEBUG }, /* gnutls assert log */
{ {"3", "hsk", "ext"}, LOG_DEBUG }, /* gnutls handshake log */
{ {"4", "rec"}, LOG_DEBUG }, /* gnutls record log */
{ {"5", "dtls"}, LOG_DEBUG }, /* gnutls DTLS log */
{ {"6", "buf"}, LOG_DEBUG },
{ {"7", "write", "read"}, LOG_DEBUG },
{ {"8"}, LOG_DEBUG },
{ {"9", "enc", "int"}, LOG_DEBUG },
};
static void log_func_gnutls(int level, const char *message) {
assert_se(message);
if (0 <= level && level < (int) ELEMENTSOF(gnutls_log_map)) {
if (gnutls_log_map[level].enabled)
log_internal(gnutls_log_map[level].level, 0, NULL, 0, NULL, "gnutls %d/%s: %s", level, gnutls_log_map[level].names[1], message);
} else {
log_debug("Received GNUTLS message with unknown level %d.", level);
log_internal(LOG_DEBUG, 0, NULL, 0, NULL, "gnutls: %s", message);
}
}
static void log_reset_gnutls_level(void) {
int i;
for (i = ELEMENTSOF(gnutls_log_map) - 1; i >= 0; i--)
if (gnutls_log_map[i].enabled) {
log_debug("Setting gnutls log level to %d", i);
gnutls_global_set_log_level(i);
break;
}
}
static int log_enable_gnutls_category(const char *cat) {
unsigned i;
if (streq(cat, "all")) {
for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
gnutls_log_map[i].enabled = true;
log_reset_gnutls_level();
return 0;
} else
for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
if (strv_contains((char**)gnutls_log_map[i].names, cat)) {
gnutls_log_map[i].enabled = true;
log_reset_gnutls_level();
return 0;
}
log_error("No such log category: %s", cat);
return -EINVAL;
}
int setup_gnutls_logger(char **categories) {
char **cat;
int r;
gnutls_global_set_log_function(log_func_gnutls);
if (categories) {
STRV_FOREACH(cat, categories) {
r = log_enable_gnutls_category(*cat);
if (r < 0)
return r;
}
} else
log_reset_gnutls_level();
return 0;
}
static int verify_cert_authorized(gnutls_session_t session) {
unsigned status;
gnutls_certificate_type_t type;
gnutls_datum_t out;
int r;
r = gnutls_certificate_verify_peers2(session, &status);
if (r < 0)
return log_error_errno(r, "gnutls_certificate_verify_peers2 failed: %m");
type = gnutls_certificate_type_get(session);
r = gnutls_certificate_verification_status_print(status, type, &out, 0);
if (r < 0)
return log_error_errno(r, "gnutls_certificate_verification_status_print failed: %m");
log_debug("Certificate status: %s", out.data);
gnutls_free(out.data);
return status == 0 ? 0 : -EPERM;
}
static int get_client_cert(gnutls_session_t session, gnutls_x509_crt_t *client_cert) {
const gnutls_datum_t *pcert;
unsigned listsize;
gnutls_x509_crt_t cert;
int r;
assert(session);
assert(client_cert);
pcert = gnutls_certificate_get_peers(session, &listsize);
if (!pcert || !listsize) {
log_error("Failed to retrieve certificate chain");
return -EINVAL;
}
r = gnutls_x509_crt_init(&cert);
if (r < 0) {
log_error("Failed to initialize client certificate");
return r;
}
/* Note that by passing values between 0 and listsize here, you
can get access to the CA's certs */
r = gnutls_x509_crt_import(cert, &pcert[0], GNUTLS_X509_FMT_DER);
if (r < 0) {
log_error("Failed to import client certificate");
gnutls_x509_crt_deinit(cert);
return r;
}
*client_cert = cert;
return 0;
}
static int get_auth_dn(gnutls_x509_crt_t client_cert, char **buf) {
size_t len = 0;
int r;
assert(buf);
assert(*buf == NULL);
r = gnutls_x509_crt_get_dn(client_cert, NULL, &len);
if (r != GNUTLS_E_SHORT_MEMORY_BUFFER) {
log_error("gnutls_x509_crt_get_dn failed");
return r;
}
*buf = malloc(len);
if (!*buf)
return log_oom();
gnutls_x509_crt_get_dn(client_cert, *buf, &len);
return 0;
}
static inline void gnutls_x509_crt_deinitp(gnutls_x509_crt_t *p) {
gnutls_x509_crt_deinit(*p);
}
int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
const union MHD_ConnectionInfo *ci;
gnutls_session_t session;
_cleanup_(gnutls_x509_crt_deinitp) gnutls_x509_crt_t client_cert = NULL;
_cleanup_free_ char *buf = NULL;
int r;
assert(connection);
assert(code);
*code = 0;
ci = MHD_get_connection_info(connection,
MHD_CONNECTION_INFO_GNUTLS_SESSION);
if (!ci) {
log_error("MHD_get_connection_info failed: session is unencrypted");
*code = mhd_respond(connection, MHD_HTTP_FORBIDDEN,
"Encrypted connection is required");
return -EPERM;
}
session = ci->tls_session;
assert(session);
r = get_client_cert(session, &client_cert);
if (r < 0) {
*code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
"Authorization through certificate is required");
return -EPERM;
}
r = get_auth_dn(client_cert, &buf);
if (r < 0) {
*code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
"Failed to determine distinguished name from certificate");
return -EPERM;
}
log_debug("Connection from %s", buf);
if (hostname) {
*hostname = buf;
buf = NULL;
}
r = verify_cert_authorized(session);
if (r < 0) {
log_warning("Client is not authorized");
*code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
"Client certificate not signed by recognized authority");
}
return r;
}
#else
int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
return -EPERM;
}
int setup_gnutls_logger(char **categories) {
if (categories)
log_notice("Ignoring specified gnutls logging categories — gnutls not available.");
return 0;
}
#endif
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