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gnupg/tools/gpg-wks-client.c

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/* gpg-wks-client.c - A client for the Web Key Service protocols.
* Copyright (C) 2016 Werner Koch
*
* 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/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
#include "i18n.h"
#include "sysutils.h"
#include "init.h"
#include "asshelp.h"
#include "userids.h"
#include "ccparray.h"
#include "exectool.h"
#include "mbox-util.h"
#include "name-value.h"
#include "call-dirmngr.h"
#include "mime-maker.h"
#include "send-mail.h"
#include "gpg-wks.h"
/* Constants to identify the commands and options. */
enum cmd_and_opt_values
{
aNull = 0,
oQuiet = 'q',
oVerbose = 'v',
oOutput = 'o',
oDebug = 500,
aSupported,
aCreate,
aReceive,
aRead,
oGpgProgram,
oSend,
oFakeSubmissionAddr,
oDummy
};
/* The list of commands and options. */
static ARGPARSE_OPTS opts[] = {
ARGPARSE_group (300, ("@Commands:\n ")),
ARGPARSE_c (aSupported, "supported",
("check whether provider supports WKS")),
ARGPARSE_c (aCreate, "create",
("create a publication request")),
ARGPARSE_c (aReceive, "receive",
("receive a MIME confirmation request")),
ARGPARSE_c (aRead, "read",
("receive a plain text confirmation request")),
ARGPARSE_group (301, ("@\nOptions:\n ")),
ARGPARSE_s_n (oVerbose, "verbose", ("verbose")),
ARGPARSE_s_n (oQuiet, "quiet", ("be somewhat more quiet")),
ARGPARSE_s_s (oDebug, "debug", "@"),
ARGPARSE_s_s (oGpgProgram, "gpg", "@"),
ARGPARSE_s_n (oSend, "send", "send the mail using sendmail"),
ARGPARSE_s_s (oOutput, "output", "|FILE|write the mail to FILE"),
ARGPARSE_s_s (oFakeSubmissionAddr, "fake-submission-addr", "@"),
ARGPARSE_end ()
};
/* The list of supported debug flags. */
static struct debug_flags_s debug_flags [] =
{
{ DBG_MIME_VALUE , "mime" },
{ DBG_PARSER_VALUE , "parser" },
{ DBG_CRYPTO_VALUE , "crypto" },
{ DBG_MEMORY_VALUE , "memory" },
{ DBG_MEMSTAT_VALUE, "memstat" },
{ DBG_IPC_VALUE , "ipc" },
{ DBG_EXTPROG_VALUE, "extprog" },
{ 0, NULL }
};
/* Value of the option --fake-submission-addr. */
const char *fake_submission_addr;
static void wrong_args (const char *text) GPGRT_ATTR_NORETURN;
static gpg_error_t command_supported (char *userid);
static gpg_error_t command_send (const char *fingerprint, char *userid);
static gpg_error_t encrypt_response (estream_t *r_output, estream_t input,
const char *addrspec);
static gpg_error_t read_confirmation_request (estream_t msg);
static gpg_error_t command_receive_cb (void *opaque,
const char *mediatype, estream_t fp,
unsigned int flags);
/* Print usage information and and provide strings for help. */
static const char *
my_strusage( int level )
{
const char *p;
switch (level)
{
case 11: p = "gpg-wks-client (@GNUPG@)";
break;
case 13: p = VERSION; break;
case 17: p = PRINTABLE_OS_NAME; break;
case 19: p = ("Please report bugs to <@EMAIL@>.\n"); break;
case 1:
case 40:
p = ("Usage: gpg-wks-client [command] [options] [args] (-h for help)");
break;
case 41:
p = ("Syntax: gpg-wks-client [command] [options] [args]\n"
"Client for the Web Key Service\n");
break;
default: p = NULL; break;
}
return p;
}
static void
wrong_args (const char *text)
{
es_fprintf (es_stderr, _("usage: %s [options] %s\n"), strusage (11), text);
exit (2);
}
/* Command line parsing. */
static enum cmd_and_opt_values
parse_arguments (ARGPARSE_ARGS *pargs, ARGPARSE_OPTS *popts)
{
enum cmd_and_opt_values cmd = 0;
int no_more_options = 0;
while (!no_more_options && optfile_parse (NULL, NULL, NULL, pargs, popts))
{
switch (pargs->r_opt)
{
case oQuiet: opt.quiet = 1; break;
case oVerbose: opt.verbose++; break;
case oDebug:
if (parse_debug_flag (pargs->r.ret_str, &opt.debug, debug_flags))
{
pargs->r_opt = ARGPARSE_INVALID_ARG;
pargs->err = ARGPARSE_PRINT_ERROR;
}
break;
case oGpgProgram:
opt.gpg_program = pargs->r.ret_str;
break;
case oSend:
opt.use_sendmail = 1;
break;
case oOutput:
opt.output = pargs->r.ret_str;
break;
case oFakeSubmissionAddr:
fake_submission_addr = pargs->r.ret_str;
break;
case aSupported:
case aCreate:
case aReceive:
case aRead:
cmd = pargs->r_opt;
break;
default: pargs->err = 2; break;
}
}
return cmd;
}
/* gpg-wks-client main. */
int
main (int argc, char **argv)
{
gpg_error_t err;
ARGPARSE_ARGS pargs;
enum cmd_and_opt_values cmd;
gnupg_reopen_std ("gpg-wks-client");
set_strusage (my_strusage);
log_set_prefix ("gpg-wks-client", GPGRT_LOG_WITH_PREFIX);
/* Make sure that our subsystems are ready. */
i18n_init();
init_common_subsystems (&argc, &argv);
assuan_set_gpg_err_source (GPG_ERR_SOURCE_DEFAULT);
setup_libassuan_logging (&opt.debug, NULL);
/* Parse the command line. */
pargs.argc = &argc;
pargs.argv = &argv;
pargs.flags = ARGPARSE_FLAG_KEEP;
cmd = parse_arguments (&pargs, opts);
if (log_get_errorcount (0))
exit (2);
/* Print a warning if an argument looks like an option. */
if (!opt.quiet && !(pargs.flags & ARGPARSE_FLAG_STOP_SEEN))
{
int i;
for (i=0; i < argc; i++)
if (argv[i][0] == '-' && argv[i][1] == '-')
log_info (("NOTE: '%s' is not considered an option\n"), argv[i]);
}
/* Set defaults for non given options. */
if (!opt.gpg_program)
opt.gpg_program = gnupg_module_name (GNUPG_MODULE_NAME_GPG);
/* Tell call-dirmngr what options we want. */
set_dirmngr_options (opt.verbose, (opt.debug & DBG_IPC_VALUE), 1);
/* Run the selected command. */
switch (cmd)
{
case aSupported:
if (argc != 1)
wrong_args ("--supported USER-ID");
err = command_supported (argv[0]);
if (err && gpg_err_code (err) != GPG_ERR_FALSE)
log_error ("checking support failed: %s\n", gpg_strerror (err));
break;
case aCreate:
if (argc != 2)
wrong_args ("--create FINGERPRINT USER-ID");
err = command_send (argv[0], argv[1]);
if (err)
log_error ("creating request failed: %s\n", gpg_strerror (err));
break;
case aReceive:
if (argc)
wrong_args ("--receive < MIME-DATA");
err = wks_receive (es_stdin, command_receive_cb, NULL);
if (err)
log_error ("processing mail failed: %s\n", gpg_strerror (err));
break;
case aRead:
if (argc)
wrong_args ("--read < WKS-DATA");
err = read_confirmation_request (es_stdin);
if (err)
log_error ("processing mail failed: %s\n", gpg_strerror (err));
break;
default:
usage (1);
break;
}
return log_get_errorcount (0)? 1:0;
}
struct get_key_status_parm_s
{
const char *fpr;
int found;
int count;
};
static void
get_key_status_cb (void *opaque, const char *keyword, char *args)
{
struct get_key_status_parm_s *parm = opaque;
/*log_debug ("%s: %s\n", keyword, args);*/
if (!strcmp (keyword, "EXPORTED"))
{
parm->count++;
if (!ascii_strcasecmp (args, parm->fpr))
parm->found = 1;
}
}
/* Get a key by fingerprint from gpg's keyring and make sure that the
* mail address ADDRSPEC is included in the key. The key is returned
* as a new memory stream at R_KEY.
*
* Fixme: After we have implemented import and export filters for gpg
* this function shall only return a key with just this user id. */
static gpg_error_t
get_key (estream_t *r_key, const char *fingerprint, const char *addrspec)
{
gpg_error_t err;
ccparray_t ccp;
const char **argv = NULL;
estream_t key = NULL;
struct get_key_status_parm_s parm;
char *filterexp = NULL;
memset (&parm, 0, sizeof parm);
*r_key = NULL;
key = es_fopenmem (0, "w+b");
if (!key)
{
err = gpg_error_from_syserror ();
log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
goto leave;
}
/* Prefix the key with the MIME content type. */
es_fputs ("Content-Type: application/pgp-keys\n"
"\n", key);
filterexp = es_bsprintf ("keep-uid=mbox = %s", addrspec);
if (!filterexp)
{
err = gpg_error_from_syserror ();
log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
goto leave;
}
ccparray_init (&ccp, 0);
ccparray_put (&ccp, "--no-options");
if (!opt.verbose)
ccparray_put (&ccp, "--quiet");
else if (opt.verbose > 1)
ccparray_put (&ccp, "--verbose");
ccparray_put (&ccp, "--batch");
ccparray_put (&ccp, "--status-fd=2");
ccparray_put (&ccp, "--always-trust");
ccparray_put (&ccp, "--armor");
ccparray_put (&ccp, "--export-options=export-minimal");
ccparray_put (&ccp, "--export-filter");
ccparray_put (&ccp, filterexp);
ccparray_put (&ccp, "--export");
ccparray_put (&ccp, "--");
ccparray_put (&ccp, fingerprint);
ccparray_put (&ccp, NULL);
argv = ccparray_get (&ccp, NULL);
if (!argv)
{
err = gpg_error_from_syserror ();
goto leave;
}
parm.fpr = fingerprint;
err = gnupg_exec_tool_stream (opt.gpg_program, argv, NULL,
NULL, key,
get_key_status_cb, &parm);
if (!err && parm.count > 1)
err = gpg_error (GPG_ERR_TOO_MANY);
else if (!err && !parm.found)
err = gpg_error (GPG_ERR_NOT_FOUND);
if (err)
{
log_error ("export failed: %s\n", gpg_strerror (err));
goto leave;
}
es_rewind (key);
*r_key = key;
key = NULL;
leave:
es_fclose (key);
xfree (argv);
xfree (filterexp);
return err;
}
static void
decrypt_stream_status_cb (void *opaque, const char *keyword, char *args)
{
(void)opaque;
if (DBG_CRYPTO)
log_debug ("gpg status: %s %s\n", keyword, args);
}
/* Decrypt the INPUT stream to a new stream which is stored at success
* at R_OUTPUT. */
static gpg_error_t
decrypt_stream (estream_t *r_output, estream_t input)
{
gpg_error_t err;
ccparray_t ccp;
const char **argv;
estream_t output;
*r_output = NULL;
output = es_fopenmem (0, "w+b");
if (!output)
{
err = gpg_error_from_syserror ();
log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
return err;
}
ccparray_init (&ccp, 0);
ccparray_put (&ccp, "--no-options");
/* We limit the output to 64 KiB to avoid DoS using compression
* tricks. A regular client will anyway only send a minimal key;
* that is one w/o key signatures and attribute packets. */
ccparray_put (&ccp, "--max-output=0x10000");
if (!opt.verbose)
ccparray_put (&ccp, "--quiet");
else if (opt.verbose > 1)
ccparray_put (&ccp, "--verbose");
ccparray_put (&ccp, "--batch");
ccparray_put (&ccp, "--status-fd=2");
ccparray_put (&ccp, "--decrypt");
ccparray_put (&ccp, "--");
ccparray_put (&ccp, NULL);
argv = ccparray_get (&ccp, NULL);
if (!argv)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = gnupg_exec_tool_stream (opt.gpg_program, argv, input,
NULL, output,
decrypt_stream_status_cb, NULL);
if (err)
{
log_error ("decryption failed: %s\n", gpg_strerror (err));
goto leave;
}
else if (opt.verbose)
log_info ("decryption succeeded\n");
es_rewind (output);
*r_output = output;
output = NULL;
leave:
es_fclose (output);
xfree (argv);
return err;
}
/* Check whether the provider supports the WKS protocol. */
static gpg_error_t
command_supported (char *userid)
{
gpg_error_t err;
char *addrspec = NULL;
char *submission_to = NULL;
addrspec = mailbox_from_userid (userid);
if (!addrspec)
{
log_error (_("\"%s\" is not a proper mail address\n"), userid);
err = gpg_error (GPG_ERR_INV_USER_ID);
goto leave;
}
/* Get the submission address. */
err = wkd_get_submission_address (addrspec, &submission_to);
if (err)
{
if (gpg_err_code (err) == GPG_ERR_NO_DATA
|| gpg_err_code (err) == GPG_ERR_UNKNOWN_HOST)
{
if (opt.verbose)
log_info ("provider for '%s' does NOT support WKS (%s)\n",
addrspec, gpg_strerror (err));
err = gpg_error (GPG_ERR_FALSE);
log_inc_errorcount ();
}
goto leave;
}
if (opt.verbose)
log_info ("provider for '%s' supports WKS\n", addrspec);
leave:
xfree (submission_to);
xfree (addrspec);
return err;
}
/* Locate the key by fingerprint and userid and send a publication
* request. */
static gpg_error_t
command_send (const char *fingerprint, char *userid)
{
gpg_error_t err;
KEYDB_SEARCH_DESC desc;
char *addrspec = NULL;
estream_t key = NULL;
estream_t keyenc = NULL;
char *submission_to = NULL;
mime_maker_t mime = NULL;
struct policy_flags_s policy;
memset (&policy, 0, sizeof policy);
if (classify_user_id (fingerprint, &desc, 1)
|| !(desc.mode == KEYDB_SEARCH_MODE_FPR
|| desc.mode == KEYDB_SEARCH_MODE_FPR20))
{
log_error (_("\"%s\" is not a fingerprint\n"), fingerprint);
err = gpg_error (GPG_ERR_INV_NAME);
goto leave;
}
addrspec = mailbox_from_userid (userid);
if (!addrspec)
{
log_error (_("\"%s\" is not a proper mail address\n"), userid);
err = gpg_error (GPG_ERR_INV_USER_ID);
goto leave;
}
err = get_key (&key, fingerprint, addrspec);
if (err)
goto leave;
/* Get the submission address. */
if (fake_submission_addr)
{
submission_to = xstrdup (fake_submission_addr);
err = 0;
}
else
err = wkd_get_submission_address (addrspec, &submission_to);
if (err)
goto leave;
log_info ("submitting request to '%s'\n", submission_to);
/* Get the policy flags. */
if (!fake_submission_addr)
{
estream_t mbuf;
err = wkd_get_policy_flags (addrspec, &mbuf);
if (err)
{
log_error ("error reading policy flags for '%s': %s\n",
submission_to, gpg_strerror (err));
goto leave;
}
if (mbuf)
{
err = wks_parse_policy (&policy, mbuf, 1);
es_fclose (mbuf);
if (err)
goto leave;
}
}
if (policy.auth_submit)
log_info ("no confirmation required for '%s'\n", addrspec);
/* Encrypt the key part. */
es_rewind (key);
err = encrypt_response (&keyenc, key, submission_to);
if (err)
goto leave;
es_fclose (key);
key = NULL;
/* Send the key. */
err = mime_maker_new (&mime, NULL);
if (err)
goto leave;
err = mime_maker_add_header (mime, "From", addrspec);
if (err)
goto leave;
err = mime_maker_add_header (mime, "To", submission_to);
if (err)
goto leave;
err = mime_maker_add_header (mime, "Subject", "Key publishing request");
if (err)
goto leave;
/* Tell server that we support draft version 3. */
err = mime_maker_add_header (mime, "Wks-Draft-Version", "3");
if (err)
goto leave;
err = mime_maker_add_header (mime, "Content-Type",
"multipart/encrypted; "
"protocol=\"application/pgp-encrypted\"");
if (err)
goto leave;
err = mime_maker_add_container (mime);
if (err)
goto leave;
err = mime_maker_add_header (mime, "Content-Type",
"application/pgp-encrypted");
if (err)
goto leave;
err = mime_maker_add_body (mime, "Version: 1\n");
if (err)
goto leave;
err = mime_maker_add_header (mime, "Content-Type",
"application/octet-stream");
if (err)
goto leave;
err = mime_maker_add_stream (mime, &keyenc);
if (err)
goto leave;
err = wks_send_mime (mime);
leave:
mime_maker_release (mime);
xfree (submission_to);
es_fclose (keyenc);
es_fclose (key);
xfree (addrspec);
return err;
}
static void
encrypt_response_status_cb (void *opaque, const char *keyword, char *args)
{
gpg_error_t *failure = opaque;
char *fields[2];
if (DBG_CRYPTO)
log_debug ("gpg status: %s %s\n", keyword, args);
if (!strcmp (keyword, "FAILURE"))
{
if (split_fields (args, fields, DIM (fields)) >= 2
&& !strcmp (fields[0], "encrypt"))
*failure = strtoul (fields[1], NULL, 10);
}
}
/* Encrypt the INPUT stream to a new stream which is stored at success
* at R_OUTPUT. Encryption is done for ADDRSPEC. We currently
* retrieve that key from the WKD, DANE, or from "local". "local" is
* last to prefer the latest key version but use a local copy in case
* we are working offline. It might be useful for the server to send
* the fingerprint of its encryption key - or even the entire key
* back. */
static gpg_error_t
encrypt_response (estream_t *r_output, estream_t input, const char *addrspec)
{
gpg_error_t err;
ccparray_t ccp;
const char **argv;
estream_t output;
gpg_error_t gpg_err = 0;
*r_output = NULL;
output = es_fopenmem (0, "w+b");
if (!output)
{
err = gpg_error_from_syserror ();
log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
return err;
}
ccparray_init (&ccp, 0);
ccparray_put (&ccp, "--no-options");
if (!opt.verbose)
ccparray_put (&ccp, "--quiet");
else if (opt.verbose > 1)
ccparray_put (&ccp, "--verbose");
ccparray_put (&ccp, "--batch");
ccparray_put (&ccp, "--status-fd=2");
ccparray_put (&ccp, "--always-trust");
ccparray_put (&ccp, "--armor");
if (fake_submission_addr)
ccparray_put (&ccp, "--auto-key-locate=clear,local");
else
ccparray_put (&ccp, "--auto-key-locate=clear,wkd,dane,local");
ccparray_put (&ccp, "--recipient");
ccparray_put (&ccp, addrspec);
ccparray_put (&ccp, "--encrypt");
ccparray_put (&ccp, "--");
ccparray_put (&ccp, NULL);
argv = ccparray_get (&ccp, NULL);
if (!argv)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = gnupg_exec_tool_stream (opt.gpg_program, argv, input,
NULL, output,
encrypt_response_status_cb, &gpg_err);
if (err)
{
if (gpg_err)
err = gpg_err;
log_error ("encryption failed: %s\n", gpg_strerror (err));
goto leave;
}
es_rewind (output);
*r_output = output;
output = NULL;
leave:
es_fclose (output);
xfree (argv);
return err;
}
static gpg_error_t
send_confirmation_response (const char *sender, const char *address,
const char *nonce, int encrypt)
{
gpg_error_t err;
estream_t body = NULL;
estream_t bodyenc = NULL;
mime_maker_t mime = NULL;
body = es_fopenmem (0, "w+b");
if (!body)
{
err = gpg_error_from_syserror ();
log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
return err;
}
/* It is fine to use 8 bit encoding because that is encrypted and
* only our client will see it. */
if (encrypt)
{
es_fputs ("Content-Type: application/vnd.gnupg.wks\n"
"Content-Transfer-Encoding: 8bit\n"
"\n",
body);
}
es_fprintf (body, ("type: confirmation-response\n"
"sender: %s\n"
"address: %s\n"
"nonce: %s\n"),
sender,
address,
nonce);
es_rewind (body);
if (encrypt)
{
err = encrypt_response (&bodyenc, body, sender);
if (err)
goto leave;
es_fclose (body);
body = NULL;
}
err = mime_maker_new (&mime, NULL);
if (err)
goto leave;
err = mime_maker_add_header (mime, "From", address);
if (err)
goto leave;
err = mime_maker_add_header (mime, "To", sender);
if (err)
goto leave;
err = mime_maker_add_header (mime, "Subject", "Key publication confirmation");
if (err)
goto leave;
if (encrypt)
{
err = mime_maker_add_header (mime, "Content-Type",
"multipart/encrypted; "
"protocol=\"application/pgp-encrypted\"");
if (err)
goto leave;
err = mime_maker_add_container (mime);
if (err)
goto leave;
err = mime_maker_add_header (mime, "Content-Type",
"application/pgp-encrypted");
if (err)
goto leave;
err = mime_maker_add_body (mime, "Version: 1\n");
if (err)
goto leave;
err = mime_maker_add_header (mime, "Content-Type",
"application/octet-stream");
if (err)
goto leave;
err = mime_maker_add_stream (mime, &bodyenc);
if (err)
goto leave;
}
else
{
err = mime_maker_add_header (mime, "Content-Type",
"application/vnd.gnupg.wks");
if (err)
goto leave;
err = mime_maker_add_stream (mime, &body);
if (err)
goto leave;
}
err = wks_send_mime (mime);
leave:
mime_maker_release (mime);
es_fclose (bodyenc);
es_fclose (body);
return err;
}
/* Reply to a confirmation request. The MSG has already been
* decrypted and we only need to send the nonce back. */
static gpg_error_t
process_confirmation_request (estream_t msg)
{
gpg_error_t err;
nvc_t nvc;
nve_t item;
const char *value, *sender, *address, *nonce;
err = nvc_parse (&nvc, NULL, msg);
if (err)
{
log_error ("parsing the WKS message failed: %s\n", gpg_strerror (err));
goto leave;
}
if (DBG_MIME)
{
log_debug ("request follows:\n");
nvc_write (nvc, log_get_stream ());
}
/* Check that this is a confirmation request. */
if (!((item = nvc_lookup (nvc, "type:")) && (value = nve_value (item))
&& !strcmp (value, "confirmation-request")))
{
if (item && value)
log_error ("received unexpected wks message '%s'\n", value);
else
log_error ("received invalid wks message: %s\n", "'type' missing");
err = gpg_error (GPG_ERR_UNEXPECTED_MSG);
goto leave;
}
/* FIXME: Check that the fingerprint matches the key used to decrypt the
* message. */
/* Get the address. */
if (!((item = nvc_lookup (nvc, "address:")) && (value = nve_value (item))
&& is_valid_mailbox (value)))
{
log_error ("received invalid wks message: %s\n",
"'address' missing or invalid");
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
address = value;
/* FIXME: Check that the "address" matches the User ID we want to
* publish. Also get the "fingerprint" and compare that to our to
* be published key. Further we should make sure that we actually
* decrypted using that fingerprint (which is a bit problematic if
* --read is used). */
/* Get the sender. */
if (!((item = nvc_lookup (nvc, "sender:")) && (value = nve_value (item))
&& is_valid_mailbox (value)))
{
log_error ("received invalid wks message: %s\n",
"'sender' missing or invalid");
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
sender = value;
/* FIXME: Check that the "sender" matches the From: address. */
/* Get the nonce. */
if (!((item = nvc_lookup (nvc, "nonce:")) && (value = nve_value (item))
&& strlen (value) > 16))
{
log_error ("received invalid wks message: %s\n",
"'nonce' missing or too short");
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
nonce = value;
/* Send the confirmation. If no key was found, try again without
* encryption. */
err = send_confirmation_response (sender, address, nonce, 1);
if (gpg_err_code (err) == GPG_ERR_NO_PUBKEY)
{
log_info ("no encryption key found - sending response in the clear\n");
err = send_confirmation_response (sender, address, nonce, 0);
}
leave:
nvc_release (nvc);
return err;
}
/* Read a confirmation request and decrypt it if needed. This
* function may not be used with a mail or MIME message but only with
* the actual encrypted or plaintext WKS data. */
static gpg_error_t
read_confirmation_request (estream_t msg)
{
gpg_error_t err;
int c;
estream_t plaintext = NULL;
/* We take a really simple approach to check whether MSG is
* encrypted: We know that an encrypted message is always armored
* and thus starts with a few dashes. It is even sufficient to
* check for a single dash, because that can never be a proper first
* WKS data octet. We need to skip leading spaces, though. */
while ((c = es_fgetc (msg)) == ' ' || c == '\t' || c == '\r' || c == '\n')
;
if (c == EOF)
{
log_error ("can't process an empty message\n");
return gpg_error (GPG_ERR_INV_DATA);
}
if (es_ungetc (c, msg) != c)
{
log_error ("error ungetting octet from message\n");
return gpg_error (GPG_ERR_INTERNAL);
}
if (c != '-')
err = process_confirmation_request (msg);
else
{
err = decrypt_stream (&plaintext, msg);
if (err)
log_error ("decryption failed: %s\n", gpg_strerror (err));
else
err = process_confirmation_request (plaintext);
}
es_fclose (plaintext);
return err;
}
/* Called from the MIME receiver to process the plain text data in MSG. */
static gpg_error_t
command_receive_cb (void *opaque, const char *mediatype,
estream_t msg, unsigned int flags)
{
gpg_error_t err;
(void)opaque;
(void)flags;
if (!strcmp (mediatype, "application/vnd.gnupg.wks"))
err = read_confirmation_request (msg);
else
{
log_info ("ignoring unexpected message of type '%s'\n", mediatype);
err = gpg_error (GPG_ERR_UNEXPECTED_MSG);
}
return err;
}
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