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gnupg/kbx/backend-support.c
Werner Koch c7293a4d12
kbx: Add first version of STORE command to keyboxd.
* kbx/Makefile.am (keyboxd_CFLAGS): -DKEYBOX_WITH_X509.
(keyboxd_LDADD): Add libksba.
* kbx/kbxserver.c (cmd_store): New.
* kbx/frontend.c (kbxd_store): New.
* kbx/backend-support.c (is_x509_blob): New.
(be_fingerprint_from_blob): New.
* kbx/backend-kbx.c (be_kbx_seek): Add args FPR and FPRLEN.
(be_kbx_insert): New.

Signed-off-by: Werner Koch <wk@gnupg.org>
2019-10-01 20:09:42 +02:00

277 lines
7.6 KiB
C

/* backend-support.c - Supporting functions for the backend.
* 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+
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include "keyboxd.h"
#include "../common/i18n.h"
#include "../common/asshelp.h"
#include "../common/tlv.h"
#include "backend.h"
#include "keybox-defs.h"
/* Common definition part of all backend handle. All definitions of
* this structure must start with these fields. */
struct backend_handle_s
{
enum database_types db_type;
unsigned int backend_id;
};
/* Return a string with the name of the database type T. */
const char *
strdbtype (enum database_types t)
{
switch (t)
{
case DB_TYPE_NONE: return "none";
case DB_TYPE_CACHE:return "cache";
case DB_TYPE_KBX: return "keybox";
}
return "?";
}
/* Return a new backend ID. Backend IDs are used to identify backends
* without using the actual object. The number of backend resources
* is limited because they are specified in the config file. Thus an
* overflow check is not required. */
unsigned int
be_new_backend_id (void)
{
static unsigned int last;
return ++last;
}
/* Release the backend described by HD. This is a generic function
* which dispatches to the the actual backend. */
void
be_generic_release_backend (ctrl_t ctrl, backend_handle_t hd)
{
if (!hd)
return;
switch (hd->db_type)
{
case DB_TYPE_NONE:
xfree (hd);
break;
case DB_TYPE_CACHE:
be_cache_release_resource (ctrl, hd);
break;
case DB_TYPE_KBX:
be_kbx_release_resource (ctrl, hd);
break;
default:
log_error ("%s: faulty backend handle of type %d given\n",
__func__, hd->db_type);
}
}
/* Release the request object REQ. */
void
be_release_request (db_request_t req)
{
db_request_part_t part, partn;
if (!req)
return;
for (part = req->part; part; part = partn)
{
partn = part->next;
be_kbx_release_kbx_hd (part->kbx_hd);
xfree (part);
}
}
/* Given the backend handle BACKEND_HD and the REQUEST find or
* allocate a request part for that backend and store it at R_PART.
* On error R_PART is set to NULL and an error returned. */
gpg_error_t
be_find_request_part (backend_handle_t backend_hd, db_request_t request,
db_request_part_t *r_part)
{
gpg_error_t err;
db_request_part_t part;
for (part = request->part; part; part = part->next)
if (part->backend_id == backend_hd->backend_id)
break;
if (!part)
{
part = xtrycalloc (1, sizeof *part);
if (!part)
return gpg_error_from_syserror ();
part->backend_id = backend_hd->backend_id;
if (backend_hd->db_type == DB_TYPE_KBX)
{
err = be_kbx_init_request_part (backend_hd, part);
if (err)
{
xfree (part);
return err;
}
}
part->next = request->part;
request->part = part;
}
*r_part = part;
return 0;
}
/* Return the public key (BUFFER,BUFLEN) which has the type
* PUBKEY_TYPE to the caller. */
gpg_error_t
be_return_pubkey (ctrl_t ctrl, const void *buffer, size_t buflen,
enum pubkey_types pubkey_type, const unsigned char *ubid)
{
gpg_error_t err;
char hexubid[41];
bin2hex (ubid, 20, hexubid);
err = status_printf (ctrl, "PUBKEY_INFO", "%d %s", pubkey_type, hexubid);
if (err)
goto leave;
if (ctrl->no_data_return)
err = 0;
else
err = kbxd_write_data_line(ctrl, buffer, buflen);
leave:
return err;
}
/* Return true if (BLOB/BLOBLEN) seems to be an X509 certificate. */
static int
is_x509_blob (const unsigned char *blob, size_t bloblen)
{
const unsigned char *p;
size_t n, objlen, hdrlen;
int class, tag, cons, ndef;
/* An X.509 certificate can be identified by this DER encoding:
*
* 30 82 05 B8 30 82 04 A0 A0 03 02 01 02 02 07 15 46 A0 BF 30 07 39
* ----------- +++++++++++ ----- ++++++++ --------------------------
* SEQUENCE SEQUENCE [0] INTEGER INTEGER
* (tbs) (version) (s/n)
*
*/
p = blob;
n = bloblen;
if (parse_ber_header (&p, &n, &class, &tag, &cons, &ndef, &objlen, &hdrlen))
return 0; /* Not a proper BER object. */
if (!(class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE && cons))
return 0; /* Does not start with a sequence. */
if (parse_ber_header (&p, &n, &class, &tag, &cons, &ndef, &objlen, &hdrlen))
return 0; /* Not a proper BER object. */
if (!(class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE && cons))
return 0; /* No TBS sequence. */
if (n < 7 || objlen < 7)
return 0; /* Too short: [0], version and min. s/n required. */
if (parse_ber_header (&p, &n, &class, &tag, &cons, &ndef, &objlen, &hdrlen))
return 0; /* Not a proper BER object. */
if (!(class == CLASS_CONTEXT && tag == 0 && cons))
return 0; /* No context tag. */
if (parse_ber_header (&p, &n, &class, &tag, &cons, &ndef, &objlen, &hdrlen))
return 0; /* Not a proper BER object. */
if (!(class == CLASS_UNIVERSAL && tag == TAG_INTEGER
&& !cons && objlen == 1 && n && (*p == 1 || *p == 2)))
return 0; /* Unknown X.509 version. */
p++; /* Skip version number. */
n--;
if (parse_ber_header (&p, &n, &class, &tag, &cons, &ndef, &objlen, &hdrlen))
return 0; /* Not a proper BER object. */
if (!(class == CLASS_UNIVERSAL && tag == TAG_INTEGER && !cons))
return 0; /* No s/n. */
return 1; /* Looks like an X.509 certificate. */
}
/* Return the public key type and the (primary) fingerprint for
* (BLOB,BLOBLEN). R_FPR must point to a buffer of at least 32 bytes,
* it received the fi gerprint on success with the length of that
* fingerprint stored at R_FPRLEN. R_PKTYPE receives the public key
* type. */
gpg_error_t
be_fingerprint_from_blob (const void *blob, size_t bloblen,
enum pubkey_types *r_pktype,
char *r_fpr, unsigned int *r_fprlen)
{
gpg_error_t err;
if (is_x509_blob (blob, bloblen))
{
/* Although libksba has a dedicated function to compute the
* fingerprint we compute it here directly because we know that
* we have the entire certificate here (we checked the start of
* the blob and assume that the length is also okay). */
*r_pktype = PUBKEY_TYPE_X509;
gcry_md_hash_buffer (GCRY_MD_SHA1, r_fpr, blob, bloblen);
*r_fprlen = 20;
err = 0;
}
else
{
struct _keybox_openpgp_info info;
err = _keybox_parse_openpgp (blob, bloblen, NULL, &info);
if (err)
{
log_info ("error parsing OpenPGP blob: %s\n", gpg_strerror (err));
err = gpg_error (GPG_ERR_WRONG_BLOB_TYPE);
}
else
{
*r_pktype = PUBKEY_TYPE_OPGP;
log_assert (info.primary.fprlen <= 32);
memcpy (r_fpr, info.primary.fpr, info.primary.fprlen);
*r_fprlen = info.primary.fprlen;
_keybox_destroy_openpgp_info (&info);
}
}
return err;
}