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parsecontroller.cpp
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/* @file parsecontroller.cpp
* @brief Parse a mail and decrypt / verify accordingly
*
* Copyright (C) 2016 by Bundesamt für Sicherheit in der Informationstechnik
* Software engineering by Intevation GmbH
*
* This file is part of GpgOL.
*
* GpgOL 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.
*
* GpgOL 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 program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "parsecontroller.h"
#include "attachment.h"
#include "mimedataprovider.h"
#include <gpgme++/context.h>
#include <gpgme++/decryptionresult.h>
#include <gpgme++/key.h>
#include <sstream>
#ifdef HAVE_W32_SYSTEM
#include "common.h"
/* We use UTF-8 internally. */
#undef _
# define _(a) utf8_gettext (a)
#else
# define _(a) a
#endif
const char decrypt_template_html[] = {
"<html><head></head><body>"
"<table border=\"0\" width=\"100%%\" cellspacing=\"1\" cellpadding=\"1\" bgcolor=\"#0069cc\">"
"<tr>"
"<td bgcolor=\"#0080ff\">"
"<p><span style=\"font-weight:600; background-color:#0080ff;\"><center>%s %s</center><span></p></td></tr>"
"<tr>"
"<td bgcolor=\"#e0f0ff\">"
"<center>"
"<br/>%s"
"</td></tr>"
"</table></body></html>"};
const char decrypt_template[] = {"%s %s\n\n%s"};
using namespace GpgME;
static bool
expect_no_headers (msgtype_t type)
{
return type != MSGTYPE_GPGOL_MULTIPART_SIGNED;
}
static bool
expect_no_mime (msgtype_t type)
{
return type == MSGTYPE_GPGOL_PGP_MESSAGE ||
type == MSGTYPE_GPGOL_CLEAR_SIGNED;
}
#ifdef HAVE_W32_SYSTEM
ParseController::ParseController(LPSTREAM instream, msgtype_t type):
m_inputprovider (new MimeDataProvider(instream,
expect_no_headers(type))),
m_outputprovider (new MimeDataProvider(expect_no_mime(type))),
m_type (type)
{
log_mime_parser ("%s:%s: Creating parser for stream: %p of type %i"
" expect no headers: %i expect no mime: %i",
SRCNAME, __func__, instream, type,
expect_no_headers (type), expect_no_mime (type));
}
#endif
ParseController::ParseController(FILE *instream, msgtype_t type):
m_inputprovider (new MimeDataProvider(instream,
expect_no_headers(type))),
m_outputprovider (new MimeDataProvider(expect_no_mime(type))),
m_type (type)
{
log_mime_parser ("%s:%s: Creating parser for stream: %p of type %i",
SRCNAME, __func__, instream, type);
}
ParseController::~ParseController()
{
log_debug ("%s:%s", SRCNAME, __func__);
delete m_inputprovider;
delete m_outputprovider;
}
static void
operation_for_type(msgtype_t type, bool *decrypt,
bool *verify)
{
*decrypt = false;
*verify = false;
switch (type)
{
case MSGTYPE_GPGOL_MULTIPART_ENCRYPTED:
case MSGTYPE_GPGOL_PGP_MESSAGE:
*decrypt = true;
break;
case MSGTYPE_GPGOL_MULTIPART_SIGNED:
case MSGTYPE_GPGOL_CLEAR_SIGNED:
*verify = true;
break;
case MSGTYPE_GPGOL_OPAQUE_SIGNED:
*verify = true;
break;
case MSGTYPE_GPGOL_OPAQUE_ENCRYPTED:
*decrypt = true;
break;
default:
log_error ("%s:%s: Unknown data type: %i",
SRCNAME, __func__, type);
}
}
static bool
is_smime (Data &data)
{
data.seek (0, SEEK_SET);
auto id = data.type();
data.seek (0, SEEK_SET);
return id == Data::CMSSigned || id == Data::CMSEncrypted;
}
static std::string
format_recipients(GpgME::DecryptionResult result, Protocol protocol)
{
std::string msg;
for (const auto recipient: result.recipients())
{
auto ctx = Context::createForProtocol(protocol);
Error e;
if (!ctx) {
/* Can't happen */
TRACEPOINT;
continue;
}
const auto key = ctx->key(recipient.keyID(), e, false);
delete ctx;
if (!key.isNull() && key.numUserIDs() && !e) {
msg += std::string("<br/>") + key.userIDs()[0].id() + " (0x" + recipient.keyID() + ")";
continue;
}
msg += std::string("<br/>") + _("Unknown Key:") + " 0x" + recipient.keyID();
}
return msg;
}
static std::string
format_error(GpgME::DecryptionResult result, Protocol protocol)
{
char *buf;
bool no_sec = false;
std::string msg;
if (result.error ().isCanceled () ||
result.error ().code () == GPG_ERR_NO_SECKEY)
{
msg = _("Decryption canceled or timed out.");
}
if (result.error ().code () == GPG_ERR_DECRYPT_FAILED)
{
no_sec = true;
for (const auto &recipient: result.recipients ()) {
no_sec &= (recipient.status ().code () == GPG_ERR_NO_SECKEY);
}
}
if (no_sec)
{
msg = _("No secret key found to decrypt the message. "
"It is encrypted to the following keys:");
msg += format_recipients (result, protocol);
}
else
{
msg = _("Could not decrypt the data: ");
if (result.isNull ())
{
msg += _("Failed to parse the mail.");
}
else
{
msg += result.error().asString();
}
}
if (gpgrt_asprintf (&buf, opt.prefer_html ? decrypt_template_html :
decrypt_template,
protocol == OpenPGP ? "OpenPGP" : "S/MIME",
_("Encrypted message (decryption not possible)"),
msg.c_str()) == -1)
{
log_error ("%s:%s:Failed to Format error.",
SRCNAME, __func__);
return "Failed to Format error.";
}
msg = buf;
return msg;
}
void
ParseController::setSender(const std::string &sender)
{
m_sender = sender;
}
void
ParseController::parse()
{
// Wrap the input stream in an attachment / GpgME Data
Protocol protocol;
bool decrypt, verify;
Data input (m_inputprovider);
auto inputType = input.type ();
if (inputType == Data::Type::PGPSigned)
{
verify = true;
decrypt = false;
}
else
{
operation_for_type (m_type, &decrypt, &verify);
}
if ((m_inputprovider->signature() && is_smime (*m_inputprovider->signature())) ||
is_smime (input))
{
protocol = Protocol::CMS;
}
else
{
protocol = Protocol::OpenPGP;
}
auto ctx = Context::createForProtocol (protocol);
if (!ctx)
{
log_error ("%s:%s:Failed to create context. Installation broken.",
SRCNAME, __func__);
char *buf;
const char *proto = protocol == OpenPGP ? "OpenPGP" : "S/MIME";
if (gpgrt_asprintf (&buf, opt.prefer_html ? decrypt_template_html :
decrypt_template,
proto,
_("Encrypted message (decryption not possible)"),
_("Failed to find GnuPG please ensure that GnuPG or "
"Gpg4win is properly installed.")) == -1)
{
log_error ("%s:%s:Failed format error.",
SRCNAME, __func__);
/* Should never happen */
m_error = std::string("Bad installation");
}
m_error = buf;
xfree (buf);
return;
}
ctx->setArmor(true);
if (!m_sender.empty())
{
ctx->setSender(m_sender.c_str());
}
Data output (m_outputprovider);
log_debug ("%s:%s:%p decrypt: %i verify: %i with protocol: %s sender: %s type: %i",
SRCNAME, __func__, this,
decrypt, verify,
protocol == OpenPGP ? "OpenPGP" :
protocol == CMS ? "CMS" : "Unknown",
m_sender.empty() ? "none" : m_sender.c_str(), inputType);
if (decrypt)
{
input.seek (0, SEEK_SET);
auto combined_result = ctx->decryptAndVerify(input, output);
log_debug ("%s:%s:%p decrypt / verify done.",
SRCNAME, __func__, this);
m_decrypt_result = combined_result.first;
m_verify_result = combined_result.second;
if ((!m_decrypt_result.error () &&
m_verify_result.signatures ().empty() &&
m_outputprovider->signature ()) ||
is_smime (output) ||
output.type() == Data::Type::PGPSigned)
{
/* There is a signature in the output. So we have
to verify it now as an extra step. */
input = Data (m_outputprovider);
delete m_inputprovider;
m_inputprovider = m_outputprovider;
m_outputprovider = new MimeDataProvider();
output = Data(m_outputprovider);
verify = true;
}
else
{
verify = false;
}
if (m_decrypt_result.error () || m_decrypt_result.isNull ())
{
m_error = format_error (m_decrypt_result, protocol);
}
}
if (verify)
{
const auto sig = m_inputprovider->signature();
input.seek (0, SEEK_SET);
if (sig)
{
sig->seek (0, SEEK_SET);
m_verify_result = ctx->verifyDetachedSignature(*sig, input);
log_debug ("%s:%s:%p verify done.",
SRCNAME, __func__, this);
/* Copy the input to output to do a mime parsing. */
char buf[4096];
input.seek (0, SEEK_SET);
output.seek (0, SEEK_SET);
size_t nread;
while ((nread = input.read (buf, 4096)) > 0)
{
output.write (buf, nread);
}
}
else
{
m_verify_result = ctx->verifyOpaqueSignature(input, output);
}
}
delete ctx;
log_debug ("%s:%s:%p: decrypt err: %i verify err: %i",
SRCNAME, __func__, this, m_decrypt_result.error().code(),
m_verify_result.error().code());
TRACEPOINT;
/* Ensure that the Keys for the signatures are available */
for (const auto sig: m_verify_result.signatures())
{
sig.key(true, true);
if (sig.validity() == Signature::Validity::Full ||
sig.validity() == Signature::Validity::Ultimate)
{
/* Ensure that we have the keys with ultimate
trust cached for the ui. */
get_ultimate_keys ();
}
}
if (opt.enable_debug)
{
std::stringstream ss;
ss << m_decrypt_result << '\n' << m_verify_result;
for (const auto sig: m_verify_result.signatures())
{
ss << '\n' << sig.key();
}
log_debug ("Decrypt / Verify result: %s", ss.str().c_str());
}
TRACEPOINT;
return;
}
const std::string
ParseController::get_html_body() const
{
if (m_outputprovider)
{
return m_outputprovider->get_html_body();
}
else
{
return std::string();
}
}
const std::string
ParseController::get_body() const
{
if (m_outputprovider)
{
return m_outputprovider->get_body();
}
else
{
return std::string();
}
}
const std::string
ParseController::get_body_charset() const
{
if (m_outputprovider)
{
return m_outputprovider->get_body_charset();
}
else
{
return std::string();
}
}
const std::string
ParseController::get_html_charset() const
{
if (m_outputprovider)
{
return m_outputprovider->get_html_charset();
}
else
{
return std::string();
}
}
std::vector<std::shared_ptr<Attachment> >
ParseController::get_attachments() const
{
if (m_outputprovider)
{
return m_outputprovider->get_attachments();
}
else
{
return std::vector<std::shared_ptr<Attachment> >();
}
}
GPGRT_LOCK_DEFINE(keylist_lock);
/* static */
std::vector<Key>
ParseController::get_ultimate_keys()
{
static bool s_keys_listed;
static std::vector<Key> s_ultimate_keys;
gpgrt_lock_lock (&keylist_lock);
if (s_keys_listed)
{
gpgrt_lock_unlock (&keylist_lock);
return s_ultimate_keys;
}
log_debug ("%s:%s: Starting keylisting.",
SRCNAME, __func__);
auto ctx = Context::createForProtocol (OpenPGP);
if (!ctx)
{
/* Maybe PGP broken and not S/MIME */
log_error ("%s:%s: broken installation no ctx.",
SRCNAME, __func__);
gpgrt_lock_unlock (&keylist_lock);
return s_ultimate_keys;
}
ctx->setKeyListMode (KeyListMode::Local);
Error err;
TRACEPOINT;
if ((err = ctx->startKeyListing ()))
{
log_error ("%s:%s: Failed to start keylisting err: %i: %s",
SRCNAME, __func__, err.code (), err.asString());
delete ctx;
gpgrt_lock_unlock (&keylist_lock);
return s_ultimate_keys;
}
TRACEPOINT;
while (!err)
{
const auto key = ctx->nextKey(err);
if (err || key.isNull())
{
TRACEPOINT;
break;
}
if (key.isInvalid ())
{
log_debug ("%s:%s: skipping invalid key.",
SRCNAME, __func__);
continue;
}
for (const auto uid: key.userIDs())
{
if (uid.validity() == UserID::Validity::Ultimate &&
uid.id())
{
s_ultimate_keys.push_back (key);
log_debug ("%s:%s: Adding ultimate uid.",
SRCNAME, __func__);
log_mime_parser ("%s:%s: Added uid %s.",
SRCNAME, __func__, uid.id());
break;
}
}
}
TRACEPOINT;
delete ctx;
log_debug ("%s:%s: keylisting done.",
SRCNAME, __func__);
s_keys_listed = true;
gpgrt_lock_unlock (&keylist_lock);
return s_ultimate_keys;
}

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