notmuch/util/crypto.c

222 lines
6.4 KiB
C
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/* notmuch - Not much of an email program, (just index and search)
*
* Copyright © 2012 Jameson Rollins
*
* This program 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.
*
* This program 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/ .
*
* Authors: Jameson Rollins <jrollins@finestructure.net>
*/
#include "crypto.h"
#include <strings.h>
#define unused(x) x __attribute__ ((unused))
#define ARRAY_SIZE(arr) (sizeof (arr) / sizeof (arr[0]))
#if (GMIME_MAJOR_VERSION < 3)
/* Create or pass on a GPG context (GMime 2.6) */
static notmuch_status_t
get_gpg_context (_notmuch_crypto_t *crypto, GMimeCryptoContext **ctx)
{
if (ctx == NULL || crypto == NULL)
return NOTMUCH_STATUS_NULL_POINTER;
if (crypto->gpgctx) {
*ctx = crypto->gpgctx;
return NOTMUCH_STATUS_SUCCESS;
}
/* TODO: GMimePasswordRequestFunc */
crypto->gpgctx = g_mime_gpg_context_new (NULL, crypto->gpgpath ? crypto->gpgpath : "gpg");
if (! crypto->gpgctx) {
return NOTMUCH_STATUS_FAILED_CRYPTO_CONTEXT_CREATION;
}
g_mime_gpg_context_set_use_agent ((GMimeGpgContext *) crypto->gpgctx, true);
g_mime_gpg_context_set_always_trust ((GMimeGpgContext *) crypto->gpgctx, false);
*ctx = crypto->gpgctx;
return NOTMUCH_STATUS_SUCCESS;
}
/* Create or pass on a PKCS7 context (GMime 2.6) */
static notmuch_status_t
get_pkcs7_context (_notmuch_crypto_t *crypto, GMimeCryptoContext **ctx)
{
if (ctx == NULL || crypto == NULL)
return NOTMUCH_STATUS_NULL_POINTER;
if (crypto->pkcs7ctx) {
*ctx = crypto->pkcs7ctx;
return NOTMUCH_STATUS_SUCCESS;
}
/* TODO: GMimePasswordRequestFunc */
crypto->pkcs7ctx = g_mime_pkcs7_context_new (NULL);
if (! crypto->pkcs7ctx) {
return NOTMUCH_STATUS_FAILED_CRYPTO_CONTEXT_CREATION;
}
g_mime_pkcs7_context_set_always_trust ((GMimePkcs7Context *) crypto->pkcs7ctx,
false);
*ctx = crypto->pkcs7ctx;
return NOTMUCH_STATUS_SUCCESS;
}
static const struct {
const char *protocol;
notmuch_status_t (*get_context) (_notmuch_crypto_t *crypto, GMimeCryptoContext **ctx);
} protocols[] = {
{
.protocol = "application/pgp-signature",
.get_context = get_gpg_context,
},
{
.protocol = "application/pgp-encrypted",
.get_context = get_gpg_context,
},
{
.protocol = "application/pkcs7-signature",
.get_context = get_pkcs7_context,
},
{
.protocol = "application/x-pkcs7-signature",
.get_context = get_pkcs7_context,
},
};
/* for the specified protocol return the context pointer (initializing
* if needed) */
notmuch_status_t
_notmuch_crypto_get_gmime_ctx_for_protocol (_notmuch_crypto_t *crypto,
const char *protocol,
GMimeCryptoContext **ctx)
{
if (! protocol)
return NOTMUCH_STATUS_MALFORMED_CRYPTO_PROTOCOL;
/* As per RFC 1847 section 2.1: "the [protocol] value token is
* comprised of the type and sub-type tokens of the Content-Type".
* As per RFC 1521 section 2: "Content-Type values, subtypes, and
* parameter names as defined in this document are
* case-insensitive." Thus, we use strcasecmp for the protocol.
*/
for (size_t i = 0; i < ARRAY_SIZE (protocols); i++) {
if (strcasecmp (protocol, protocols[i].protocol) == 0)
return protocols[i].get_context (crypto, ctx);
}
return NOTMUCH_STATUS_UNKNOWN_CRYPTO_PROTOCOL;
}
void
_notmuch_crypto_cleanup (_notmuch_crypto_t *crypto)
{
if (crypto->gpgctx) {
g_object_unref (crypto->gpgctx);
crypto->gpgctx = NULL;
}
if (crypto->pkcs7ctx) {
g_object_unref (crypto->pkcs7ctx);
crypto->pkcs7ctx = NULL;
}
}
#else
void _notmuch_crypto_cleanup (unused(_notmuch_crypto_t *crypto))
{
}
#endif
GMimeObject *
_notmuch_crypto_decrypt (bool *attempted,
notmuch_decryption_policy_t decrypt,
notmuch_message_t *message,
g_mime_3_unused(GMimeCryptoContext* crypto_ctx),
GMimeMultipartEncrypted *part,
GMimeDecryptResult **decrypt_result,
GError **err)
{
GMimeObject *ret = NULL;
if (decrypt == NOTMUCH_DECRYPT_FALSE)
return NULL;
/* the versions of notmuch that can support session key decryption */
#if HAVE_GMIME_SESSION_KEYS
if (message) {
notmuch_message_properties_t *list = NULL;
for (list = notmuch_message_get_properties (message, "session-key", TRUE);
notmuch_message_properties_valid (list); notmuch_message_properties_move_to_next (list)) {
if (err && *err) {
g_error_free (*err);
*err = NULL;
}
if (attempted)
*attempted = true;
#if (GMIME_MAJOR_VERSION < 3)
ret = g_mime_multipart_encrypted_decrypt_session (part,
crypto_ctx,
notmuch_message_properties_value (list),
decrypt_result, err);
#else
ret = g_mime_multipart_encrypted_decrypt (part,
GMIME_DECRYPT_NONE,
notmuch_message_properties_value (list),
decrypt_result, err);
#endif
if (ret)
break;
}
if (list)
notmuch_message_properties_destroy (list);
if (ret)
return ret;
}
#endif
if (err && *err) {
g_error_free (*err);
*err = NULL;
}
if (decrypt == NOTMUCH_DECRYPT_AUTO)
return ret;
if (attempted)
*attempted = true;
#if (GMIME_MAJOR_VERSION < 3)
#if HAVE_GMIME_SESSION_KEYS
gboolean oldgetsk = g_mime_crypto_context_get_retrieve_session_key (crypto_ctx);
gboolean newgetsk = (decrypt == NOTMUCH_DECRYPT_TRUE && decrypt_result);
if (newgetsk != oldgetsk)
/* This could return an error, but we can't do anything about it, so ignore it */
g_mime_crypto_context_set_retrieve_session_key (crypto_ctx, newgetsk, NULL);
#endif
ret = g_mime_multipart_encrypted_decrypt(part, crypto_ctx,
decrypt_result, err);
#if HAVE_GMIME_SESSION_KEYS
if (newgetsk != oldgetsk)
g_mime_crypto_context_set_retrieve_session_key (crypto_ctx, oldgetsk, NULL);
#endif
#else
GMimeDecryptFlags flags = GMIME_DECRYPT_NONE;
if (decrypt == NOTMUCH_DECRYPT_TRUE && decrypt_result)
flags |= GMIME_DECRYPT_EXPORT_SESSION_KEY;
ret = g_mime_multipart_encrypted_decrypt(part, flags, NULL,
decrypt_result, err);
#endif
return ret;
}