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gnupg/kbx/backend-kbx.c

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/* backend-kbx.c - Keybox format backend for keyboxd
* Copyright (C) 2019 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-or-later
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include "keyboxd.h"
#include "../common/i18n.h"
#include "backend.h"
#include "keybox.h"
/* Our definition of the backend handle. */
struct backend_handle_s
{
enum database_types db_type; /* Always DB_TYPE_KBX. */
unsigned int backend_id; /* Always the id of the backend. */
void *token; /* Used to create a new KEYBOX_HANDLE. */
char filename[1];
};
/* Check that the file FILENAME is a valid keybox file which can be
* used here. Common return codes:
*
* 0 := Valid keybox file
* GPG_ERR_ENOENT := No such file
* GPG_ERR_NO_OBJ := File exists with size zero.
* GPG_ERR_INV_OBJ:= File exists but is not a keybox file.
*/
static gpg_error_t
check_kbx_file_magic (const char *filename)
{
gpg_error_t err;
u32 magic;
unsigned char verbuf[4];
estream_t fp;
fp = es_fopen (filename, "rb");
if (!fp)
return gpg_error_from_syserror ();
err = gpg_error (GPG_ERR_INV_OBJ);
if (es_fread (&magic, 4, 1, fp) == 1 )
{
if (es_fread (&verbuf, 4, 1, fp) == 1
&& verbuf[0] == 1
&& es_fread (&magic, 4, 1, fp) == 1
&& !memcmp (&magic, "KBXf", 4))
{
err = 0;
}
}
else /* Maybe empty: Let's create it. */
err = gpg_error (GPG_ERR_NO_OBJ);
es_fclose (fp);
return err;
}
/* Create new keybox file. This can also be used if the keybox
* already exists but has a length of zero. Do not use it in any
* other cases. */
static gpg_error_t
create_keybox (const char *filename)
{
gpg_error_t err;
dotlock_t lockhd = NULL;
estream_t fp;
/* To avoid races with other temporary instances of keyboxd trying
* to create or update the keybox, we do the next stuff in a locked
* state. */
lockhd = dotlock_create (filename, 0);
if (!lockhd)
{
err = gpg_error_from_syserror ();
/* A reason for this to fail is that the directory is not
* writable. However, this whole locking stuff does not make
* sense if this is the case. An empty non-writable directory
* with no keybox is not really useful at all. */
if (opt.verbose)
log_info ("can't allocate lock for '%s': %s\n",
filename, gpg_strerror (err));
return err;
}
if ( dotlock_take (lockhd, -1) )
{
err = gpg_error_from_syserror ();
/* This is something bad. Probably a stale lockfile. */
log_info ("can't lock '%s': %s\n", filename, gpg_strerror (err));
goto leave;
}
/* Make sure that at least one record is in a new keybox file, so
* that the detection magic will work the next time it is used.
* We always set the OpenPGP blobs maybe available flag. */
fp = es_fopen (filename, "w+b,mode=-rw-------");
if (!fp)
{
err = gpg_error_from_syserror ();
log_error (_("error creating keybox '%s': %s\n"),
filename, gpg_strerror (err));
goto leave;
}
err = _keybox_write_header_blob (NULL, fp, 1);
es_fclose (fp);
if (err)
{
log_error (_("error creating keybox '%s': %s\n"),
filename, gpg_strerror (err));
goto leave;
}
if (!opt.quiet)
log_info (_("keybox '%s' created\n"), filename);
err = 0;
leave:
if (lockhd)
{
dotlock_release (lockhd);
dotlock_destroy (lockhd);
}
return err;
}
/* Install a new resource and return a handle for that backend. */
gpg_error_t
be_kbx_add_resource (ctrl_t ctrl, backend_handle_t *r_hd,
const char *filename, int readonly)
{
gpg_error_t err;
backend_handle_t hd;
void *token;
(void)ctrl;
*r_hd = NULL;
hd = xtrycalloc (1, sizeof *hd + strlen (filename));
if (!hd)
return gpg_error_from_syserror ();
hd->db_type = DB_TYPE_KBX;
strcpy (hd->filename, filename);
err = check_kbx_file_magic (filename);
switch (gpg_err_code (err))
{
case 0:
break;
case GPG_ERR_ENOENT:
case GPG_ERR_NO_OBJ:
if (readonly)
{
err = gpg_error (GPG_ERR_ENOENT);
goto leave;
}
err = create_keybox (filename);
if (err)
goto leave;
break;
default:
goto leave;
}
err = keybox_register_file (filename, 0, &token);
if (err)
goto leave;
hd->backend_id = be_new_backend_id ();
hd->token = token;
*r_hd = hd;
hd = NULL;
leave:
xfree (hd);
return err;
}
/* Release the backend handle HD and all its resources. HD is not
* valid after a call to this function. */
void
be_kbx_release_resource (ctrl_t ctrl, backend_handle_t hd)
{
(void)ctrl;
if (!hd)
return;
hd->db_type = DB_TYPE_NONE;
xfree (hd);
}
void
be_kbx_release_kbx_hd (KEYBOX_HANDLE kbx_hd)
{
keybox_release (kbx_hd);
}
/* Helper for be_find_request_part to initialize a kbx request part. */
gpg_error_t
be_kbx_init_request_part (backend_handle_t backend_hd, db_request_part_t part)
{
part->kbx_hd = keybox_new_openpgp (backend_hd->token, 0);
if (!part->kbx_hd)
return gpg_error_from_syserror ();
return 0;
}
/* Search for the keys described by (DESC,NDESC) and return them to
* the caller. BACKEND_HD is the handle for this backend and REQUEST
* is the current database request object. */
gpg_error_t
be_kbx_search (ctrl_t ctrl, backend_handle_t backend_hd, db_request_t request,
KEYDB_SEARCH_DESC *desc, unsigned int ndesc)
{
gpg_error_t err;
db_request_part_t part;
size_t descindex;
unsigned long skipped_long_blobs;
log_assert (backend_hd && backend_hd->db_type == DB_TYPE_KBX);
log_assert (request);
/* Find the specific request part or allocate it. */
err = be_find_request_part (backend_hd, request, &part);
if (err)
goto leave;
if (!desc)
err = keybox_search_reset (part->kbx_hd);
else
err = keybox_search (part->kbx_hd, desc, ndesc, KEYBOX_BLOBTYPE_PGP,
&descindex, &skipped_long_blobs);
if (err == -1)
err = gpg_error (GPG_ERR_EOF);
if (desc && !err)
{
/* Successful search operation. */
void *buffer;
size_t buflen;
enum pubkey_types pubkey_type;
unsigned char ubid[UBID_LEN];
err = keybox_get_data (part->kbx_hd, &buffer, &buflen,
&pubkey_type, ubid);
if (err)
goto leave;
err = be_return_pubkey (ctrl, buffer, buflen, pubkey_type, ubid);
if (!err)
be_cache_pubkey (ctrl, ubid, buffer, buflen, pubkey_type);
xfree (buffer);
}
leave:
return err;
}
/* Seek in the keybox to the given UBID (if UBID is not NULL) or to
* the primary fingerprint specified by (FPR,FPRLEN). BACKEND_HD is
* the handle for this backend and REQUEST is the current database
* request object. This does a dummy read so that the next search
* operation starts right after that UBID. */
gpg_error_t
be_kbx_seek (ctrl_t ctrl, backend_handle_t backend_hd,
db_request_t request, const unsigned char *ubid)
{
gpg_error_t err;
db_request_part_t part;
size_t descindex;
unsigned long skipped_long_blobs;
KEYDB_SEARCH_DESC desc;
(void)ctrl;
log_assert (backend_hd && backend_hd->db_type == DB_TYPE_KBX);
log_assert (request);
memset (&desc, 0, sizeof desc);
desc.mode = KEYDB_SEARCH_MODE_UBID;
memcpy (desc.u.ubid, ubid, UBID_LEN);
/* Find the specific request part or allocate it. */
err = be_find_request_part (backend_hd, request, &part);
if (err)
goto leave;
err = keybox_search_reset (part->kbx_hd);
if (!err)
err = keybox_search (part->kbx_hd, &desc, 1, 0,
&descindex, &skipped_long_blobs);
if (err == -1)
err = gpg_error (GPG_ERR_EOF);
leave:
return err;
}
/* Insert (BLOB,BLOBLEN) into the keybox. BACKEND_HD is the handle
* for this backend and REQUEST is the current database request
* object. */
gpg_error_t
be_kbx_insert (ctrl_t ctrl, backend_handle_t backend_hd,
db_request_t request, enum pubkey_types pktype,
const void *blob, size_t bloblen)
{
gpg_error_t err;
db_request_part_t part;
ksba_cert_t cert = NULL;
(void)ctrl;
log_assert (backend_hd && backend_hd->db_type == DB_TYPE_KBX);
log_assert (request);
/* Find the specific request part or allocate it. */
err = be_find_request_part (backend_hd, request, &part);
if (err)
goto leave;
if (pktype == PUBKEY_TYPE_OPGP)
err = keybox_insert_keyblock (part->kbx_hd, blob, bloblen);
else if (pktype == PUBKEY_TYPE_X509)
{
unsigned char sha1[20];
err = ksba_cert_new (&cert);
if (err)
goto leave;
err = ksba_cert_init_from_mem (cert, blob, bloblen);
if (err)
goto leave;
gcry_md_hash_buffer (GCRY_MD_SHA1, sha1, blob, bloblen);
err = keybox_insert_cert (part->kbx_hd, cert, sha1);
}
else
err = gpg_error (GPG_ERR_WRONG_BLOB_TYPE);
leave:
ksba_cert_release (cert);
return err;
}
/* Update (BLOB,BLOBLEN) in the keybox. BACKEND_HD is the handle for
* this backend and REQUEST is the current database request object. */
gpg_error_t
be_kbx_update (ctrl_t ctrl, backend_handle_t backend_hd,
db_request_t request, enum pubkey_types pktype,
const void *blob, size_t bloblen)
{
gpg_error_t err;
db_request_part_t part;
ksba_cert_t cert = NULL;
(void)ctrl;
log_assert (backend_hd && backend_hd->db_type == DB_TYPE_KBX);
log_assert (request);
/* Find the specific request part or allocate it. */
err = be_find_request_part (backend_hd, request, &part);
if (err)
goto leave;
/* FIXME: We make use of the fact that we know that the caller
* already did a keybox search. This needs to be made more
* explicit. */
if (pktype == PUBKEY_TYPE_OPGP)
{
err = keybox_update_keyblock (part->kbx_hd, blob, bloblen);
}
else if (pktype == PUBKEY_TYPE_X509)
{
unsigned char sha1[20];
err = ksba_cert_new (&cert);
if (err)
goto leave;
err = ksba_cert_init_from_mem (cert, blob, bloblen);
if (err)
goto leave;
gcry_md_hash_buffer (GCRY_MD_SHA1, sha1, blob, bloblen);
err = keybox_update_cert (part->kbx_hd, cert, sha1);
}
else
err = gpg_error (GPG_ERR_WRONG_BLOB_TYPE);
leave:
ksba_cert_release (cert);
return err;
}
/* Delete the blob from the keybox. BACKEND_HD is the handle for
* this backend and REQUEST is the current database request object. */
gpg_error_t
be_kbx_delete (ctrl_t ctrl, backend_handle_t backend_hd, db_request_t request)
{
gpg_error_t err;
db_request_part_t part;
(void)ctrl;
log_assert (backend_hd && backend_hd->db_type == DB_TYPE_KBX);
log_assert (request);
/* Find the specific request part or allocate it. */
err = be_find_request_part (backend_hd, request, &part);
if (err)
goto leave;
/* FIXME: We make use of the fact that we know that the caller
* already did a keybox search. This needs to be made more
* explicit. */
err = keybox_delete (part->kbx_hd);
leave:
return err;
}
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