src/journal-remote/microhttpd-util.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2012 Lennart Poettering
   7   Copyright 2012 Zbigniew Jędrzejewski-Szmek
   8
   9   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
  11   the Free Software Foundation; either version 2.1 of the License, or
  12   (at your option) any later version.
  13
  14   systemd is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   Lesser General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  21 ***/
  22
  23 #include <stddef.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 #include "microhttpd-util.h"
  28 #include "log.h"
  29 #include "macro.h"
  30 #include "util.h"
  31 #include "strv.h"
  32
  33 #ifdef HAVE_GNUTLS
  34 #include <gnutls/gnutls.h>
  35 #include <gnutls/x509.h>
  36 #endif
  37
  38 void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
  39         char *f;
  40
  41         f = strjoina("microhttpd: ", fmt);
  42
  43         DISABLE_WARNING_FORMAT_NONLITERAL;
  44         log_internalv(LOG_INFO, 0, NULL, 0, NULL, f, ap);
  45         REENABLE_WARNING;
  46 }
  47
  48
  49 static int mhd_respond_internal(struct MHD_Connection *connection,
  50                                 enum MHD_RequestTerminationCode code,
  51                                 char *buffer,
  52                                 size_t size,
  53                                 enum MHD_ResponseMemoryMode mode) {
  54         struct MHD_Response *response;
  55         int r;
  56
  57         assert(connection);
  58
  59         response = MHD_create_response_from_buffer(size, buffer, mode);
  60         if (!response)
  61                 return MHD_NO;
  62
  63         log_debug("Queing response %u: %s", code, buffer);
  64         MHD_add_response_header(response, "Content-Type", "text/plain");
  65         r = MHD_queue_response(connection, code, response);
  66         MHD_destroy_response(response);
  67
  68         return r;
  69 }
  70
  71 int mhd_respond(struct MHD_Connection *connection,
  72                 enum MHD_RequestTerminationCode code,
  73                 const char *message) {
  74
  75         return mhd_respond_internal(connection, code,
  76                                     (char*) message, strlen(message),
  77                                     MHD_RESPMEM_PERSISTENT);
  78 }
  79
  80 int mhd_respond_oom(struct MHD_Connection *connection) {
  81         return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE,  "Out of memory.\n");
  82 }
  83
  84 int mhd_respondf(struct MHD_Connection *connection,
  85                  enum MHD_RequestTerminationCode code,
  86                  const char *format, ...) {
  87
  88         char *m;
  89         int r;
  90         va_list ap;
  91
  92         assert(connection);
  93         assert(format);
  94
  95         va_start(ap, format);
  96         r = vasprintf(&m, format, ap);
  97         va_end(ap);
  98
  99         if (r < 0)
 100                 return respond_oom(connection);
 101
 102         return mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
 103 }
 104
 105 #ifdef HAVE_GNUTLS
 106
 107 static struct {
 108         const char *const names[4];
 109         int level;
 110         bool enabled;
 111 } gnutls_log_map[] = {
 112         { {"0"},                  LOG_DEBUG },
 113         { {"1", "audit"},         LOG_WARNING, true}, /* gnutls session audit */
 114         { {"2", "assert"},        LOG_DEBUG },        /* gnutls assert log */
 115         { {"3", "hsk", "ext"},    LOG_DEBUG },        /* gnutls handshake log */
 116         { {"4", "rec"},           LOG_DEBUG },        /* gnutls record log */
 117         { {"5", "dtls"},          LOG_DEBUG },        /* gnutls DTLS log */
 118         { {"6", "buf"},           LOG_DEBUG },
 119         { {"7", "write", "read"}, LOG_DEBUG },
 120         { {"8"},                  LOG_DEBUG },
 121         { {"9", "enc", "int"},    LOG_DEBUG },
 122 };
 123
 124 void log_func_gnutls(int level, const char *message) {
 125         assert_se(message);
 126
 127         if (0 <= level && level < (int) ELEMENTSOF(gnutls_log_map)) {
 128                 if (gnutls_log_map[level].enabled)
 129                         log_internal(gnutls_log_map[level].level, 0, NULL, 0, NULL, "gnutls %d/%s: %s", level, gnutls_log_map[level].names[1], message);
 130         } else {
 131                 log_debug("Received GNUTLS message with unknown level %d.", level);
 132                 log_internal(LOG_DEBUG, 0, NULL, 0, NULL, "gnutls: %s", message);
 133         }
 134 }
 135
 136 int log_enable_gnutls_category(const char *cat) {
 137         unsigned i;
 138
 139         if (streq(cat, "all")) {
 140                 for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
 141                         gnutls_log_map[i].enabled = true;
 142                 log_reset_gnutls_level();
 143                 return 0;
 144         } else
 145                 for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
 146                         if (strv_contains((char**)gnutls_log_map[i].names, cat)) {
 147                                 gnutls_log_map[i].enabled = true;
 148                                 log_reset_gnutls_level();
 149                                 return 0;
 150                         }
 151         log_error("No such log category: %s", cat);
 152         return -EINVAL;
 153 }
 154
 155 void log_reset_gnutls_level(void) {
 156         int i;
 157
 158         for (i = ELEMENTSOF(gnutls_log_map) - 1; i >= 0; i--)
 159                 if (gnutls_log_map[i].enabled) {
 160                         log_debug("Setting gnutls log level to %d", i);
 161                         gnutls_global_set_log_level(i);
 162                         break;
 163                 }
 164 }
 165
 166 static int verify_cert_authorized(gnutls_session_t session) {
 167         unsigned status;
 168         gnutls_certificate_type_t type;
 169         gnutls_datum_t out;
 170         int r;
 171
 172         r = gnutls_certificate_verify_peers2(session, &status);
 173         if (r < 0)
 174                 return log_error_errno(r, "gnutls_certificate_verify_peers2 failed: %m");
 175
 176         type = gnutls_certificate_type_get(session);
 177         r = gnutls_certificate_verification_status_print(status, type, &out, 0);
 178         if (r < 0)
 179                 return log_error_errno(r, "gnutls_certificate_verification_status_print failed: %m");
 180
 181         log_info("Certificate status: %s", out.data);
 182         gnutls_free(out.data);
 183
 184         return status == 0 ? 0 : -EPERM;
 185 }
 186
 187 static int get_client_cert(gnutls_session_t session, gnutls_x509_crt_t *client_cert) {
 188         const gnutls_datum_t *pcert;
 189         unsigned listsize;
 190         gnutls_x509_crt_t cert;
 191         int r;
 192
 193         assert(session);
 194         assert(client_cert);
 195
 196         pcert = gnutls_certificate_get_peers(session, &listsize);
 197         if (!pcert || !listsize) {
 198                 log_error("Failed to retrieve certificate chain");
 199                 return -EINVAL;
 200         }
 201
 202         r = gnutls_x509_crt_init(&cert);
 203         if (r < 0) {
 204                 log_error("Failed to initialize client certificate");
 205                 return r;
 206         }
 207
 208         /* Note that by passing values between 0 and listsize here, you
 209            can get access to the CA's certs */
 210         r = gnutls_x509_crt_import(cert, &pcert[0], GNUTLS_X509_FMT_DER);
 211         if (r < 0) {
 212                 log_error("Failed to import client certificate");
 213                 gnutls_x509_crt_deinit(cert);
 214                 return r;
 215         }
 216
 217         *client_cert = cert;
 218         return 0;
 219 }
 220
 221 static int get_auth_dn(gnutls_x509_crt_t client_cert, char **buf) {
 222         size_t len = 0;
 223         int r;
 224
 225         assert(buf);
 226         assert(*buf == NULL);
 227
 228         r = gnutls_x509_crt_get_dn(client_cert, NULL, &len);
 229         if (r != GNUTLS_E_SHORT_MEMORY_BUFFER) {
 230                 log_error("gnutls_x509_crt_get_dn failed");
 231                 return r;
 232         }
 233
 234         *buf = malloc(len);
 235         if (!*buf)
 236                 return log_oom();
 237
 238         gnutls_x509_crt_get_dn(client_cert, *buf, &len);
 239         return 0;
 240 }
 241
 242 int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
 243         const union MHD_ConnectionInfo *ci;
 244         gnutls_session_t session;
 245         gnutls_x509_crt_t client_cert;
 246         _cleanup_free_ char *buf = NULL;
 247         int r;
 248
 249         assert(connection);
 250         assert(code);
 251
 252         *code = 0;
 253
 254         ci = MHD_get_connection_info(connection,
 255                                      MHD_CONNECTION_INFO_GNUTLS_SESSION);
 256         if (!ci) {
 257                 log_error("MHD_get_connection_info failed: session is unencrypted");
 258                 *code = mhd_respond(connection, MHD_HTTP_FORBIDDEN,
 259                                     "Encrypted connection is required");
 260                 return -EPERM;
 261         }
 262         session = ci->tls_session;
 263         assert(session);
 264
 265         r = get_client_cert(session, &client_cert);
 266         if (r < 0) {
 267                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 268                                     "Authorization through certificate is required");
 269                 return -EPERM;
 270         }
 271
 272         r = get_auth_dn(client_cert, &buf);
 273         if (r < 0) {
 274                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 275                                     "Failed to determine distinguished name from certificate");
 276                 return -EPERM;
 277         }
 278
 279         log_info("Connection from %s", buf);
 280
 281         if (hostname) {
 282                 *hostname = buf;
 283                 buf = NULL;
 284         }
 285
 286         r = verify_cert_authorized(session);
 287         if (r < 0) {
 288                 log_warning("Client is not authorized");
 289                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 290                                     "Client certificate not signed by recognized authority");
 291         }
 292         return r;
 293 }
 294
 295 #else
 296 int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
 297         return -EPERM;
 298 }
 299 #endif