1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467
|
/* kbx-client-util.c - Utility functions to implement a keyboxd client
* Copyright (C) 2020 g10 Code GmbH
*
* This file is part of GnuPG.
*
* GnuPG 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.
*
* GnuPG 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 <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: GPL-3.0+
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <npth.h>
#include <assuan.h>
#include "../common/util.h"
#include "../common/membuf.h"
#include "../common/i18n.h"
#include "../common/asshelp.h"
#include "../common/exechelp.h"
#include "../common/sysutils.h"
#include "../common/host2net.h"
#include "kbx-client-util.h"
#define MAX_DATABLOB_SIZE (16*1024*1024)
/* This object is used to implement a client to the keyboxd. */
struct kbx_client_data_s
{
/* The used assuan context. */
assuan_context_t ctx;
/* A stream used to receive data. If this is NULL D-lines are used
* to receive the data. */
estream_t fp;
/* Condition variable to sync the datastream with the command. */
npth_mutex_t mutex;
npth_cond_t cond;
/* The data received from the keyboxd and an error code if there was
* a problem (in which case DATA is also set to NULL. This is only
* used if FP is not NULL. */
char *data;
size_t datalen;
gpg_error_t dataerr;
/* Helper variables in case D-lines are used (FP is NULL) */
char *dlinedata;
size_t dlinedatalen;
gpg_error_t dlineerr;
};
static void *datastream_thread (void *arg);
static void
lock_datastream (kbx_client_data_t kcd)
{
int rc = npth_mutex_lock (&kcd->mutex);
if (rc)
log_fatal ("%s: failed to acquire mutex: %s\n", __func__,
gpg_strerror (gpg_error_from_errno (rc)));
}
static void
unlock_datastream (kbx_client_data_t kcd)
{
int rc = npth_mutex_unlock (&kcd->mutex);
if (rc)
log_fatal ("%s: failed to release mutex: %s\n", __func__,
gpg_strerror (gpg_error_from_errno (rc)));
}
/* Setup the pipe used for receiving data from the keyboxd. Store the
* info on KCD. */
static gpg_error_t
prepare_data_pipe (kbx_client_data_t kcd)
{
gpg_error_t err;
int rc;
int inpipe[2];
estream_t infp;
npth_t thread;
npth_attr_t tattr;
kcd->fp = NULL;
kcd->data = NULL;
kcd->datalen = 0;
kcd->dataerr = 0;
err = gnupg_create_inbound_pipe (inpipe, &infp, 0);
if (err)
{
log_error ("error creating inbound pipe: %s\n", gpg_strerror (err));
return err; /* That should not happen. */
}
err = assuan_sendfd (kcd->ctx, INT2FD (inpipe[1]));
if (err)
{
log_error ("sending sending fd %d to keyboxd: %s <%s>\n",
inpipe[1], gpg_strerror (err), gpg_strsource (err));
es_fclose (infp);
gnupg_close_pipe (inpipe[1]);
return 0; /* Server may not support fd-passing. */
}
err = assuan_transact (kcd->ctx, "OUTPUT FD",
NULL, NULL, NULL, NULL, NULL, NULL);
if (err)
{
log_info ("keyboxd does not accept our fd: %s <%s>\n",
gpg_strerror (err), gpg_strsource (err));
es_fclose (infp);
return 0;
}
kcd->fp = infp;
rc = npth_attr_init (&tattr);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("error preparing thread for keyboxd: %s\n",gpg_strerror (err));
es_fclose (infp);
kcd->fp = NULL;
return err;
}
npth_attr_setdetachstate (&tattr, NPTH_CREATE_DETACHED);
rc = npth_create (&thread, &tattr, datastream_thread, kcd);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("error spawning thread for keyboxd: %s\n", gpg_strerror (err));
npth_attr_destroy (&tattr);
es_fclose (infp);
kcd->fp = NULL;
return err;
}
return 0;
}
/* The thread used to read from the data stream. This is running as
* long as the connection and its datastream exists. */
static void *
datastream_thread (void *arg)
{
kbx_client_data_t kcd = arg;
gpg_error_t err;
int rc;
unsigned char lenbuf[4];
size_t nread, datalen;
char *data = NULL;
char *tmpdata;
/* log_debug ("%s: started\n", __func__); */
while (kcd->fp)
{
/* log_debug ("%s: waiting ...\n", __func__); */
if (es_read (kcd->fp, lenbuf, 4, &nread))
{
err = gpg_error_from_syserror ();
if (gpg_err_code (err) == GPG_ERR_EAGAIN)
continue;
log_error ("error reading data length from keyboxd: %s\n",
gpg_strerror (err));
gnupg_sleep (1);
continue;
}
if (nread != 4)
{
err = gpg_error (GPG_ERR_EIO);
log_error ("error reading data length from keyboxd: %s\n",
"short read");
continue;
}
datalen = buf32_to_size_t (lenbuf);
/* log_debug ("keyboxd announced %zu bytes\n", datalen); */
if (!datalen)
{
log_info ("ignoring empty blob received from keyboxd\n");
continue;
}
if (datalen > MAX_DATABLOB_SIZE)
{
err = gpg_error (GPG_ERR_TOO_LARGE);
/* Drop connection or what shall we do? */
}
else if (!(data = xtrymalloc (datalen+1)))
{
err = gpg_error_from_syserror ();
}
else if (es_read (kcd->fp, data, datalen, &nread))
{
err = gpg_error_from_syserror ();
}
else if (datalen != nread)
{
err = gpg_error (GPG_ERR_TOO_SHORT);
}
else
err = 0;
if (err)
{
log_error ("error reading data from keyboxd: %s <%s>\n",
gpg_strerror (err), gpg_strsource (err));
xfree (data);
data = NULL;
datalen = 0;
}
else
{
/* log_debug ("parsing datastream succeeded\n"); */
}
/* Thread-safe assignment to the result var: */
tmpdata = kcd->data;
kcd->data = data;
kcd->datalen = datalen;
kcd->dataerr = err;
xfree (tmpdata);
data = NULL;
/* Tell the main thread. */
lock_datastream (kcd);
rc = npth_cond_signal (&kcd->cond);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("%s: signaling condition failed: %s\n",
__func__, gpg_strerror (err));
}
unlock_datastream (kcd);
}
/* log_debug ("%s: finished\n", __func__); */
return NULL;
}
/* Create a new keyboxd client data object and return it at R_KCD.
* CTX is the assuan context to be used for connecting the keyboxd.
* If dlines is set, communication is done without fd passing via
* D-lines. */
gpg_error_t
kbx_client_data_new (kbx_client_data_t *r_kcd, assuan_context_t ctx,
int dlines)
{
kbx_client_data_t kcd;
int rc;
gpg_error_t err;
kcd = xtrycalloc (1, sizeof *kcd);
if (!kcd)
return gpg_error_from_syserror ();
kcd->ctx = ctx;
if (dlines)
goto leave;
rc = npth_mutex_init (&kcd->mutex, NULL);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("error initializing mutex: %s\n", gpg_strerror (err));
xfree (kcd);
return err;
}
rc = npth_cond_init (&kcd->cond, NULL);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("error initializing condition: %s\n", gpg_strerror (err));
npth_mutex_destroy (&kcd->mutex);
xfree (kcd);
return err;
}
err = prepare_data_pipe (kcd);
if (err)
{
npth_cond_destroy (&kcd->cond);
npth_mutex_destroy (&kcd->mutex);
xfree (kcd);
return err;
}
leave:
*r_kcd = kcd;
return 0;
}
void
kbx_client_data_release (kbx_client_data_t kcd)
{
estream_t fp;
if (!kcd)
return;
fp = kcd->fp;
kcd->fp = NULL;
es_fclose (fp); /* That close should let the thread run into an error. */
/* FIXME: Make thread killing explicit. Otherwise we run in a
* log_fatal due to the destroyed mutex. */
npth_cond_destroy (&kcd->cond);
npth_mutex_destroy (&kcd->mutex);
xfree (kcd);
}
/* Send a simple Assuan command to the server. */
gpg_error_t
kbx_client_data_simple (kbx_client_data_t kcd, const char *command)
{
/* log_debug ("%s: sending command '%s'\n", __func__, command); */
return assuan_transact (kcd->ctx, command,
NULL, NULL, NULL, NULL, NULL, NULL);
}
/* Send the COMMAND down to the keyboxd associated with KCD.
* STATUS_CB and STATUS_CB_VALUE are the usual status callback as used
* by assuan_transact. After this function has returned success
* kbx_client_data_wait needs to be called to actually return the
* data. */
gpg_error_t
kbx_client_data_cmd (kbx_client_data_t kcd, const char *command,
gpg_error_t (*status_cb)(void *opaque, const char *line),
void *status_cb_value)
{
gpg_error_t err;
xfree (kcd->dlinedata);
kcd->dlinedata = NULL;
kcd->dlinedatalen = 0;
kcd->dlineerr = 0;
if (kcd->fp)
{
/* log_debug ("%s: sending command '%s'\n", __func__, command); */
err = assuan_transact (kcd->ctx, command,
NULL, NULL,
NULL, NULL,
status_cb, status_cb_value);
if (err)
{
if (gpg_err_code (err) != GPG_ERR_NOT_FOUND
&& gpg_err_code (err) != GPG_ERR_NOTHING_FOUND)
log_debug ("%s: finished command with error: %s\n",
__func__, gpg_strerror (err));
/* Fixme: On unexpected errors we need a way to cancel the
* data stream. Probably it will be best to close and
* reopen it. */
}
}
else /* Slower D-line version if fd-passing is not available. */
{
membuf_t mb;
size_t len;
/* log_debug ("%s: sending command '%s' (no fd-passing)\n", */
/* __func__, command); */
init_membuf (&mb, 8192);
err = assuan_transact (kcd->ctx, command,
put_membuf_cb, &mb,
NULL, NULL,
status_cb, status_cb_value);
if (err)
{
/* if (gpg_err_code (err) != GPG_ERR_NOT_FOUND */
/* && gpg_err_code (err) != GPG_ERR_NOTHING_FOUND) */
/* log_debug ("%s: finished command with error: %s\n", */
/* __func__, gpg_strerror (err)); */
xfree (get_membuf (&mb, &len));
kcd->dlineerr = err;
goto leave;
}
kcd->dlinedata = get_membuf (&mb, &kcd->dlinedatalen);
if (!kcd->dlinedata)
{
err = gpg_error_from_syserror ();
goto leave;
}
}
leave:
return err;
}
/* Wait for the data from the server and on success return it at
* (R_DATA, R_DATALEN). */
gpg_error_t
kbx_client_data_wait (kbx_client_data_t kcd, char **r_data, size_t *r_datalen)
{
gpg_error_t err = 0;
int rc;
*r_data = NULL;
*r_datalen = 0;
if (kcd->fp)
{
lock_datastream (kcd);
if (!kcd->data && !kcd->dataerr)
{
/* log_debug ("%s: waiting on datastream_cond ...\n", __func__); */
rc = npth_cond_wait (&kcd->cond, &kcd->mutex);
if (rc)
{
err = gpg_error_from_errno (rc);
log_error ("%s: waiting on condition failed: %s\n",
__func__, gpg_strerror (err));
}
/* else */
/* log_debug ("%s: waiting on datastream.cond done\n", __func__); */
}
*r_data = kcd->data;
kcd->data = NULL;
*r_datalen = kcd->datalen;
err = err? err : kcd->dataerr;
unlock_datastream (kcd);
}
else
{
*r_data = kcd->dlinedata;
kcd->dlinedata = NULL;
*r_datalen = kcd->dlinedatalen;
err = kcd->dlineerr;
}
return err;
}
|