mirror of
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6502bb0d2a
* common/compliance.c (gnupg_pk_is_allowed): Rework to always allow verification. * g10/mainproc.c (check_sig_and_print): Print a con-compliant warning. * g10/sig-check.c (check_signature2): Use log_error instead of log_info. -- We should be able to verify all signatures. So we only print a warning. That is the same beheavour as for untrusted keys etc. GnuPG-bug-id: 3311 Signed-off-by: Werner Koch <wk@gnupg.org>
591 lines
15 KiB
C
591 lines
15 KiB
C
/* compliance.c - Functions for compliance modi
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* Copyright (C) 2017 g10 Code GmbH
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* Copyright (C) 2017 Bundesamt für Sicherheit in der Informationstechnik
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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 either
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*
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* - the GNU Lesser General Public License as published by the Free
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* Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* or
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*
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* - the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* or both in parallel, as here.
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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 General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <gcrypt.h>
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#include "openpgpdefs.h"
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#include "logging.h"
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#include "util.h"
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#include "i18n.h"
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#include "compliance.h"
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static int initialized;
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static int module;
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/* Initializes the module. Must be called with the current
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* GNUPG_MODULE_NAME. Checks a few invariants, and tunes the policies
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* for the given module. */
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void
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gnupg_initialize_compliance (int gnupg_module_name)
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{
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log_assert (! initialized);
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/* We accept both OpenPGP-style and gcrypt-style algorithm ids.
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* Assert that they are compatible. */
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log_assert ((int) GCRY_PK_RSA == (int) PUBKEY_ALGO_RSA);
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log_assert ((int) GCRY_PK_RSA_E == (int) PUBKEY_ALGO_RSA_E);
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log_assert ((int) GCRY_PK_RSA_S == (int) PUBKEY_ALGO_RSA_S);
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log_assert ((int) GCRY_PK_ELG_E == (int) PUBKEY_ALGO_ELGAMAL_E);
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log_assert ((int) GCRY_PK_DSA == (int) PUBKEY_ALGO_DSA);
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log_assert ((int) GCRY_PK_ECC == (int) PUBKEY_ALGO_ECDH);
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log_assert ((int) GCRY_PK_ELG == (int) PUBKEY_ALGO_ELGAMAL);
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log_assert ((int) GCRY_CIPHER_NONE == (int) CIPHER_ALGO_NONE);
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log_assert ((int) GCRY_CIPHER_IDEA == (int) CIPHER_ALGO_IDEA);
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log_assert ((int) GCRY_CIPHER_3DES == (int) CIPHER_ALGO_3DES);
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log_assert ((int) GCRY_CIPHER_CAST5 == (int) CIPHER_ALGO_CAST5);
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log_assert ((int) GCRY_CIPHER_BLOWFISH == (int) CIPHER_ALGO_BLOWFISH);
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log_assert ((int) GCRY_CIPHER_AES == (int) CIPHER_ALGO_AES);
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log_assert ((int) GCRY_CIPHER_AES192 == (int) CIPHER_ALGO_AES192);
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log_assert ((int) GCRY_CIPHER_AES256 == (int) CIPHER_ALGO_AES256);
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log_assert ((int) GCRY_CIPHER_TWOFISH == (int) CIPHER_ALGO_TWOFISH);
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log_assert ((int) GCRY_MD_MD5 == (int) DIGEST_ALGO_MD5);
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log_assert ((int) GCRY_MD_SHA1 == (int) DIGEST_ALGO_SHA1);
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log_assert ((int) GCRY_MD_RMD160 == (int) DIGEST_ALGO_RMD160);
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log_assert ((int) GCRY_MD_SHA256 == (int) DIGEST_ALGO_SHA256);
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log_assert ((int) GCRY_MD_SHA384 == (int) DIGEST_ALGO_SHA384);
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log_assert ((int) GCRY_MD_SHA512 == (int) DIGEST_ALGO_SHA512);
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log_assert ((int) GCRY_MD_SHA224 == (int) DIGEST_ALGO_SHA224);
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switch (gnupg_module_name)
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{
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case GNUPG_MODULE_NAME_GPGSM:
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case GNUPG_MODULE_NAME_GPG:
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break;
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default:
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log_assert (!"no policies for this module");
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}
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module = gnupg_module_name;
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initialized = 1;
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}
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/* Return true if ALGO with a key of KEYLENGTH is compliant to the
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* given COMPLIANCE mode. If KEY is not NULL, various bits of
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* information will be extracted from it. If CURVENAME is not NULL, it
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* is assumed to be the already computed. ALGO may be either an
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* OpenPGP-style pubkey_algo_t, or a gcrypt-style enum gcry_pk_algos,
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* both are compatible from the point of view of this function. */
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int
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gnupg_pk_is_compliant (enum gnupg_compliance_mode compliance, int algo,
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gcry_mpi_t key[], unsigned int keylength,
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const char *curvename)
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{
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enum { is_rsa, is_dsa, is_elg, is_ecc } algotype;
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int result = 0;
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if (! initialized)
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return 0;
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switch (algo)
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{
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case PUBKEY_ALGO_RSA:
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case PUBKEY_ALGO_RSA_E:
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case PUBKEY_ALGO_RSA_S:
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algotype = is_rsa;
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break;
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case PUBKEY_ALGO_DSA:
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algotype = is_dsa;
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break;
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case PUBKEY_ALGO_ELGAMAL_E:
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algotype = is_elg;
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break;
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case PUBKEY_ALGO_ECDH:
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case PUBKEY_ALGO_ECDSA:
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case PUBKEY_ALGO_EDDSA:
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algotype = is_ecc;
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break;
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case PUBKEY_ALGO_ELGAMAL:
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return 0; /* Signing with Elgamal is not at all supported. */
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default: /* Unknown. */
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return 0;
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}
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if (compliance == CO_DE_VS)
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{
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char *curve = NULL;
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switch (algotype)
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{
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case is_elg:
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result = 0;
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break;
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case is_rsa:
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result = (keylength == 2048
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|| keylength == 3072
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|| keylength == 4096);
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break;
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case is_dsa:
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if (key)
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{
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size_t P = gcry_mpi_get_nbits (key[0]);
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size_t Q = gcry_mpi_get_nbits (key[1]);
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result = (Q == 256
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&& (P == 2048 || P == 3072));
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}
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break;
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case is_ecc:
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if (!curvename && key)
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{
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curve = openpgp_oid_to_str (key[0]);
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curvename = openpgp_oid_to_curve (curve, 0);
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if (!curvename)
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curvename = curve;
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}
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result = (curvename
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&& (algo == PUBKEY_ALGO_ECDH
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|| algo == PUBKEY_ALGO_ECDSA)
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&& (!strcmp (curvename, "brainpoolP256r1")
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|| !strcmp (curvename, "brainpoolP384r1")
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|| !strcmp (curvename, "brainpoolP512r1")));
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break;
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default:
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result = 0;
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}
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xfree (curve);
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}
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else
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{
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result = 1; /* Assume compliance. */
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}
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return result;
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}
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/* Return true if ALGO with the given KEYLENGTH is allowed in the
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* given COMPLIANCE mode. USE specifies for which use case the
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* predicate is evaluated. This way policies can be strict in what
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* they produce, and liberal in what they accept. */
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int
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gnupg_pk_is_allowed (enum gnupg_compliance_mode compliance,
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enum pk_use_case use, int algo, gcry_mpi_t key[],
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unsigned int keylength, const char *curvename)
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{
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int result = 0;
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if (! initialized)
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return 1;
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switch (compliance)
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{
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case CO_DE_VS:
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switch (algo)
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{
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case PUBKEY_ALGO_RSA:
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case PUBKEY_ALGO_RSA_E:
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case PUBKEY_ALGO_RSA_S:
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switch (use)
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{
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case PK_USE_DECRYPTION:
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case PK_USE_VERIFICATION:
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result = 1;
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break;
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case PK_USE_ENCRYPTION:
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case PK_USE_SIGNING:
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result = (keylength == 2048
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|| keylength == 3072
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|| keylength == 4096);
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break;
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default:
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log_assert (!"reached");
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}
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break;
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case PUBKEY_ALGO_DSA:
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if (use == PK_USE_VERIFICATION)
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result = 1;
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else if (use == PK_USE_SIGNING && key)
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{
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size_t P = gcry_mpi_get_nbits (key[0]);
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size_t Q = gcry_mpi_get_nbits (key[1]);
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result = (Q == 256 && (P == 2048 || P == 3072));
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}
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break;
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case PUBKEY_ALGO_ELGAMAL:
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case PUBKEY_ALGO_ELGAMAL_E:
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result = (use == PK_USE_DECRYPTION);
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break;
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case PUBKEY_ALGO_ECDH:
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if (use == PK_USE_DECRYPTION)
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result = 1;
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else if (use == PK_USE_ENCRYPTION)
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{
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char *curve = NULL;
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if (!curvename && key)
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{
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curve = openpgp_oid_to_str (key[0]);
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curvename = openpgp_oid_to_curve (curve, 0);
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if (!curvename)
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curvename = curve;
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}
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result = (curvename
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&& (!strcmp (curvename, "brainpoolP256r1")
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|| !strcmp (curvename, "brainpoolP384r1")
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|| !strcmp (curvename, "brainpoolP512r1")));
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xfree (curve);
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}
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break;
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case PUBKEY_ALGO_ECDSA:
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if (use == PK_USE_VERIFICATION)
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result = 1;
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else
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{
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char *curve = NULL;
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if (! curvename && key)
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{
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curve = openpgp_oid_to_str (key[0]);
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curvename = openpgp_oid_to_curve (curve, 0);
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if (!curvename)
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curvename = curve;
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}
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result = (use == PK_USE_SIGNING
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&& curvename
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&& (!strcmp (curvename, "brainpoolP256r1")
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|| !strcmp (curvename, "brainpoolP384r1")
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|| !strcmp (curvename, "brainpoolP512r1")));
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xfree (curve);
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}
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break;
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case PUBKEY_ALGO_EDDSA:
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break;
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default:
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break;
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}
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break;
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default:
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/* The default policy is to allow all algorithms. */
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result = 1;
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}
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return result;
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}
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/* Return true if (CIPHER, MODE) is compliant to the given COMPLIANCE mode. */
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int
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gnupg_cipher_is_compliant (enum gnupg_compliance_mode compliance,
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cipher_algo_t cipher,
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enum gcry_cipher_modes mode)
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{
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if (! initialized)
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return 0;
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switch (compliance)
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{
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case CO_DE_VS:
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switch (cipher)
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{
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case CIPHER_ALGO_AES:
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case CIPHER_ALGO_AES192:
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case CIPHER_ALGO_AES256:
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case CIPHER_ALGO_3DES:
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switch (module)
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{
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case GNUPG_MODULE_NAME_GPG:
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return mode == GCRY_CIPHER_MODE_CFB;
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case GNUPG_MODULE_NAME_GPGSM:
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return mode == GCRY_CIPHER_MODE_CBC;
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}
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log_assert (!"reached");
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default:
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return 0;
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}
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log_assert (!"reached");
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default:
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return 0;
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}
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log_assert (!"reached");
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}
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/* Return true if CIPHER is allowed in the given COMPLIANCE mode. If
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* PRODUCER is true, the predicate is evaluated for the producer, if
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* false for the consumer. This way policies can be strict in what
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* they produce, and liberal in what they accept. */
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int
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gnupg_cipher_is_allowed (enum gnupg_compliance_mode compliance, int producer,
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cipher_algo_t cipher,
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enum gcry_cipher_modes mode)
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{
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if (! initialized)
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return 1;
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switch (compliance)
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{
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case CO_DE_VS:
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switch (cipher)
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{
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case CIPHER_ALGO_AES:
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case CIPHER_ALGO_AES192:
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case CIPHER_ALGO_AES256:
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case CIPHER_ALGO_3DES:
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switch (module)
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{
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case GNUPG_MODULE_NAME_GPG:
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return (mode == GCRY_CIPHER_MODE_NONE
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|| mode == GCRY_CIPHER_MODE_CFB);
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case GNUPG_MODULE_NAME_GPGSM:
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return (mode == GCRY_CIPHER_MODE_NONE
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|| mode == GCRY_CIPHER_MODE_CBC);
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}
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log_assert (!"reached");
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case CIPHER_ALGO_BLOWFISH:
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case CIPHER_ALGO_CAMELLIA128:
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case CIPHER_ALGO_CAMELLIA192:
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case CIPHER_ALGO_CAMELLIA256:
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case CIPHER_ALGO_CAST5:
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case CIPHER_ALGO_IDEA:
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case CIPHER_ALGO_TWOFISH:
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return (module == GNUPG_MODULE_NAME_GPG
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&& (mode == GCRY_CIPHER_MODE_NONE
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|| mode == GCRY_CIPHER_MODE_CFB)
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&& ! producer);
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default:
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return 0;
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}
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log_assert (!"reached");
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default:
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/* The default policy is to allow all algorithms. */
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return 1;
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}
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log_assert (!"reached");
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}
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/* Return true if DIGEST is compliant to the given COMPLIANCE mode. */
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int
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gnupg_digest_is_compliant (enum gnupg_compliance_mode compliance,
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digest_algo_t digest)
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{
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if (! initialized)
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return 0;
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switch (compliance)
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{
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case CO_DE_VS:
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switch (digest)
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{
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case DIGEST_ALGO_SHA256:
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case DIGEST_ALGO_SHA384:
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case DIGEST_ALGO_SHA512:
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return 1;
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default:
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return 0;
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}
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log_assert (!"reached");
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default:
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return 0;
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}
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log_assert (!"reached");
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}
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/* Return true if DIGEST is allowed in the given COMPLIANCE mode. If
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* PRODUCER is true, the predicate is evaluated for the producer, if
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* false for the consumer. This way policies can be strict in what
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* they produce, and liberal in what they accept. */
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int
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gnupg_digest_is_allowed (enum gnupg_compliance_mode compliance, int producer,
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digest_algo_t digest)
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{
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if (! initialized)
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return 1;
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switch (compliance)
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{
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case CO_DE_VS:
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switch (digest)
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{
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case DIGEST_ALGO_SHA256:
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case DIGEST_ALGO_SHA384:
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case DIGEST_ALGO_SHA512:
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return 1;
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case DIGEST_ALGO_SHA1:
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case DIGEST_ALGO_SHA224:
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case DIGEST_ALGO_RMD160:
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return ! producer;
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case DIGEST_ALGO_MD5:
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return ! producer && module == GNUPG_MODULE_NAME_GPGSM;
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default:
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return 0;
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}
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log_assert (!"reached");
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default:
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/* The default policy is to allow all algorithms. */
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return 1;
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}
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log_assert (!"reached");
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}
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/* Return True if the random number generator is compliant in
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* COMPLIANCE mode. */
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int
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gnupg_rng_is_compliant (enum gnupg_compliance_mode compliance)
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{
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static int result = -1;
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if (result != -1)
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; /* Use cached result. */
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else if (compliance == CO_DE_VS)
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{
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/* In DE_VS mode under Windows we require that the JENT RNG
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* is active. */
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#ifdef HAVE_W32_SYSTEM
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# if GCRYPT_VERSION_NUMBER >= 0x010800
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char *buf;
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char *fields[5];
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buf = gcry_get_config (0, "rng-type");
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if (buf
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&& split_fields_colon (buf, fields, DIM (fields)) >= 5
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&& atoi (fields[4]) > 0)
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result = 1;
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else
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result = 0;
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gcry_free (buf);
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# else
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result = 0; /* No JENT - can't be compliant. */
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# endif
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#else /*!HAVE_W32_SYSTEM*/
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result = 1; /* Not Windows - RNG is good. */
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#endif /*!HAVE_W32_SYSTEM*/
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}
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else
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result = 1;
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return result;
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}
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const char *
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gnupg_status_compliance_flag (enum gnupg_compliance_mode compliance)
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{
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switch (compliance)
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{
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case CO_GNUPG:
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return "8";
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case CO_RFC4880:
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case CO_RFC2440:
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case CO_PGP6:
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case CO_PGP7:
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case CO_PGP8:
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log_assert (!"no status code assigned for this compliance mode");
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case CO_DE_VS:
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return "23";
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}
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log_assert (!"invalid compliance mode");
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}
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/* Parse the value of --compliance. Returns the value corresponding
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* to the given STRING according to OPTIONS of size LENGTH, or -1
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* indicating that the lookup was unsuccessful, or the list of options
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* was printed. If quiet is false, an additional hint to use 'help'
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* is printed on unsuccessful lookups. */
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int
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gnupg_parse_compliance_option (const char *string,
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struct gnupg_compliance_option options[],
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size_t length,
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int quiet)
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{
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size_t i;
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|
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if (! ascii_strcasecmp (string, "help"))
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{
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log_info (_("valid values for option '%s':\n"), "--compliance");
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for (i = 0; i < length; i++)
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log_info (" %s\n", options[i].keyword);
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|
return -1;
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}
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|
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for (i = 0; i < length; i++)
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if (! ascii_strcasecmp (string, options[i].keyword))
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return options[i].value;
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|
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log_error (_("invalid value for option '%s'\n"), "--compliance");
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if (! quiet)
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log_info (_("(use \"help\" to list choices)\n"));
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return -1;
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}
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|
|
|
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/* Return the command line option for the given COMPLIANCE mode. */
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|
const char *
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|
gnupg_compliance_option_string (enum gnupg_compliance_mode compliance)
|
|
{
|
|
switch (compliance)
|
|
{
|
|
case CO_GNUPG: return "--compliance=gnupg";
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|
case CO_RFC4880: return "--compliance=openpgp";
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|
case CO_RFC2440: return "--compliance=rfc2440";
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|
case CO_PGP6: return "--compliance=pgp6";
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|
case CO_PGP7: return "--compliance=pgp7";
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|
case CO_PGP8: return "--compliance=pgp8";
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|
case CO_DE_VS: return "--compliance=de-vs";
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|
}
|
|
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log_assert (!"invalid compliance mode");
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|
}
|