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![Jakub Jelen](/assets/img/avatar_default.png)
* agent/command.c (cmd_genkey): Use goto instead of return. * agent/cvt-openpgp.c (convert_from_openpgp_main): Ditto. * agent/genkey.c (agent_ask_new_passphrase): Fix typo to free correct pointer (agent_genkey): Release memory * agent/gpg-agent.c (check_own_socket): Free sockname * agent/protect-tool.c (read_key): Free buf. (agent_askpin): Free passphrase -- Signed-off-by: Jakub Jelen <jjelen@redhat.com> Changed original patch to not add a free before a GPG_ERR_BUG. Signed-off-by: Werner Koch <wk@gnupg.org> GnuPG-bug-id: 5393
389 lines
10 KiB
C
389 lines
10 KiB
C
/* tlv-builder.c - Build DER encoded objects
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* Copyright (C) 2020 g10 Code GmbH
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*
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* This file is part of GnuPG.
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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* SPDX-License-Identifier: LGPL-2.1-or-later
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <gpg-error.h>
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#include "util.h"
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#include "tlv.h"
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struct item_s
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{
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int class;
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int tag;
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unsigned int is_constructed:1; /* This is a constructed element. */
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unsigned int is_stop:1; /* This is a STOP item. */
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const void *value;
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size_t valuelen;
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char *buffer; /* Malloced space or NULL. */
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};
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struct tlv_builder_s
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{
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gpg_error_t error; /* Last error. */
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int use_secure; /* Use secure memory for the result. */
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size_t nallocateditems; /* Number of allocated items. */
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size_t nitems; /* Number of used items. */
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struct item_s *items; /* Array of items. */
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int laststop; /* Used as return value of compute_length. */
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};
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/* Allocate a new TLV Builder instance. Returns NULL on error. If
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* SECURE is set the final object is stored in secure memory. */
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tlv_builder_t
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tlv_builder_new (int secure)
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{
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tlv_builder_t tb;
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tb = xtrycalloc (1, sizeof *tb);
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if (tb && secure)
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tb->use_secure = 1;
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return tb;
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}
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/* Make sure the array of items is large enough for one new item.
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* Records any error in TB and returns true in that case. */
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static int
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ensure_space (tlv_builder_t tb)
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{
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struct item_s *newitems;
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if (!tb || tb->error)
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return 1;
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if (tb->nitems == tb->nallocateditems)
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{
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tb->nallocateditems += 32;
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newitems = gpgrt_reallocarray (tb->items, tb->nitems,
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tb->nallocateditems, sizeof *newitems);
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if (!newitems)
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tb->error = gpg_error_from_syserror ();
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else
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tb->items = newitems;
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}
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return !!tb->error;
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}
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/* Add a new primitive element to the builder instance TB. The
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* element is described by CLASS, TAG, VALUE, and VALUEEN. CLASS and
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* TAG must describe a primitive element and (VALUE,VALUELEN) specify
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* its value. The value is a pointer and its object must not be
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* changed as long as the instance TB exists. For a TAG_NULL no vlaue
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* is expected. Errors are not returned but recorded for later
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* retrieval. */
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void
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tlv_builder_add_ptr (tlv_builder_t tb, int class, int tag,
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void *value, size_t valuelen)
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{
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if (ensure_space (tb))
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return;
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tb->items[tb->nitems].class = class;
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tb->items[tb->nitems].tag = tag;
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tb->items[tb->nitems].value = value;
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tb->items[tb->nitems].valuelen = valuelen;
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tb->nitems++;
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}
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/* This is the same as tlv_builder_add_ptr but it takes a copy of the
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* value and thus the caller does not need to care about it. */
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void
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tlv_builder_add_val (tlv_builder_t tb, int class, int tag,
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const void *value, size_t valuelen)
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{
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void *p;
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if (ensure_space (tb))
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return;
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if (!value || !valuelen)
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{
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tb->error = gpg_error (GPG_ERR_INV_VALUE);
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return;
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}
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p = tb->use_secure? xtrymalloc_secure (valuelen) : xtrymalloc (valuelen);
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if (!p)
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{
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tb->error = gpg_error_from_syserror ();
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return;
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}
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memcpy (p, value, valuelen);
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tb->items[tb->nitems].buffer = p;
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tb->items[tb->nitems].class = class;
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tb->items[tb->nitems].tag = tag;
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tb->items[tb->nitems].value = p;
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tb->items[tb->nitems].valuelen = valuelen;
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tb->nitems++;
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}
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/* Add a new constructed object to the builder instance TB. The
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* object is described by CLASS and TAG which must describe a
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* constructed object. The elements of the constructed objects are
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* added with more call to the add functions. To close a constructed
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* element a call to tlv_builer_add_end is required. Errors are not
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* returned but recorded for later retrieval. */
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void
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tlv_builder_add_tag (tlv_builder_t tb, int class, int tag)
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{
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if (ensure_space (tb))
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return;
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tb->items[tb->nitems].class = class;
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tb->items[tb->nitems].tag = tag;
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tb->items[tb->nitems].is_constructed = 1;
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tb->nitems++;
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}
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/* A call to this function closes a constructed element. This must be
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* called even for an empty constructed element. */
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void
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tlv_builder_add_end (tlv_builder_t tb)
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{
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if (ensure_space (tb))
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return;
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tb->items[tb->nitems].is_stop = 1;
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tb->nitems++;
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}
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/* Compute and set the length of all constructed elements in the item
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* array of TB starting at IDX up to the corresponding stop item. On
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* error tb->error is set. */
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static size_t
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compute_lengths (tlv_builder_t tb, int idx)
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{
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size_t total = 0;
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if (tb->error)
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return 0;
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for (; idx < tb->nitems; idx++)
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{
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if (tb->items[idx].is_stop)
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{
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tb->laststop = idx;
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break;
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}
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if (tb->items[idx].is_constructed)
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{
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tb->items[idx].valuelen = compute_lengths (tb, idx+1);
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if (tb->error)
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return 0;
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/* Note: The last processed IDX is stored at tb->LASTSTOP. */
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}
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total += get_tlv_length (tb->items[idx].class, tb->items[idx].tag,
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tb->items[idx].is_constructed,
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tb->items[idx].valuelen);
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if (tb->items[idx].is_constructed)
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idx = tb->laststop;
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}
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return total;
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}
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/* Return the constructed DER encoding and release this instance. On
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* success the object is stored at R_OBJ and its length at R_OBJLEN.
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* The caller needs to release that memory. On error NULL is stored
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* at R_OBJ and an error code is returned. Note than an error may
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* stem from any of the previous call made to this object or from
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* constructing the the DER object. */
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gpg_error_t
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tlv_builder_finalize (tlv_builder_t tb, void **r_obj, size_t *r_objlen)
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{
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gpg_error_t err;
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membuf_t mb;
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int mb_initialized = 0;
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int idx;
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*r_obj = NULL;
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*r_objlen = 0;
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if (!tb)
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return gpg_error (GPG_ERR_INTERNAL);
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if (tb->error)
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{
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err = tb->error;
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goto leave;
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}
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if (!tb->nitems || !tb->items[tb->nitems-1].is_stop)
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{
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err = gpg_error (GPG_ERR_NO_OBJ);
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goto leave;
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}
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compute_lengths (tb, 0);
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err = tb->error;
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if (err)
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goto leave;
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/* for (idx=0; idx < tb->nitems; idx++) */
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/* log_debug ("TLVB[%2d]: c=%d t=%2d %s p=%p l=%zu\n", */
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/* idx, */
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/* tb->items[idx].class, */
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/* tb->items[idx].tag, */
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/* tb->items[idx].is_stop? "stop": */
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/* tb->items[idx].is_constructed? "cons":"prim", */
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/* tb->items[idx].value, */
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/* tb->items[idx].valuelen); */
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if (tb->use_secure)
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init_membuf_secure (&mb, 512);
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else
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init_membuf (&mb, 512);
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mb_initialized = 1;
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for (idx=0; idx < tb->nitems; idx++)
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{
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if (tb->items[idx].is_stop)
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continue;
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put_tlv_to_membuf (&mb, tb->items[idx].class, tb->items[idx].tag,
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tb->items[idx].is_constructed,
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tb->items[idx].valuelen);
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if (tb->items[idx].value)
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put_membuf (&mb, tb->items[idx].value, tb->items[idx].valuelen);
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}
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*r_obj = get_membuf (&mb, r_objlen);
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if (!*r_obj)
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err = gpg_error_from_syserror ();
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mb_initialized = 0;
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leave:
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if (mb_initialized)
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xfree (get_membuf (&mb, NULL));
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for (idx=0; idx < tb->nitems; idx++)
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xfree (tb->items[idx].buffer);
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xfree (tb->items);
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xfree (tb);
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return err;
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}
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/* Write TAG of CLASS to MEMBUF. CONSTRUCTED is a flag telling
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* whether the value is constructed. LENGTH gives the length of the
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* value, if it is 0 undefinite length is assumed. LENGTH is ignored
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* for the NULL tag. TAG must be less that 0x1f. */
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void
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put_tlv_to_membuf (membuf_t *membuf, int class, int tag,
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int constructed, size_t length)
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{
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unsigned char buf[20];
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int buflen = 0;
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int i;
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if (tag < 0x1f)
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{
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*buf = (class << 6) | tag;
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if (constructed)
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*buf |= 0x20;
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buflen++;
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}
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else
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BUG ();
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if (!tag && !class)
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buf[buflen++] = 0; /* end tag */
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else if (tag == TAG_NULL && !class)
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buf[buflen++] = 0; /* NULL tag */
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else if (!length)
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buf[buflen++] = 0x80; /* indefinite length */
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else if (length < 128)
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buf[buflen++] = length;
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else
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{
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/* If we know the sizeof a size_t we could support larger
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* objects - however this is pretty ridiculous */
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i = (length <= 0xff ? 1:
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length <= 0xffff ? 2:
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length <= 0xffffff ? 3: 4);
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buf[buflen++] = (0x80 | i);
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if (i > 3)
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buf[buflen++] = length >> 24;
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if (i > 2)
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buf[buflen++] = length >> 16;
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if (i > 1)
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buf[buflen++] = length >> 8;
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buf[buflen++] = length;
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}
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put_membuf (membuf, buf, buflen);
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}
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/* Return the length of the to be constructed TLV. CONSTRUCTED is a
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* flag telling whether the value is constructed. LENGTH gives the
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* length of the value, if it is 0 undefinite length is assumed.
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* LENGTH is ignored for the NULL tag. TAG must be less that 0x1f. */
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size_t
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get_tlv_length (int class, int tag, int constructed, size_t length)
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{
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size_t buflen = 0;
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int i;
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(void)constructed; /* Not used, but passed for uniformity of such calls. */
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/* coverity[identical_branches] */
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if (tag < 0x1f)
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{
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buflen++;
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}
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else
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{
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buflen++; /* assume one and let the actual write function bail out */
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}
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if (!tag && !class)
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buflen++; /* end tag */
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else if (tag == TAG_NULL && !class)
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buflen++; /* NULL tag */
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else if (!length)
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buflen++; /* indefinite length */
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else if (length < 128)
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buflen++;
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else
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{
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i = (length <= 0xff ? 1:
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length <= 0xffff ? 2:
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length <= 0xffffff ? 3: 4);
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buflen++;
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if (i > 3)
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buflen++;
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if (i > 2)
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buflen++;
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if (i > 1)
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buflen++;
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buflen++;
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}
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return buflen + length;
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}
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