+++ /dev/null
-/* -*-c-*-
- *
- * $Id$
- *
- * Encrypting keys with passphrases
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb 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 Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <mLib/dstr.h>
-
-#include "key-data.h"
-#include "paranoia.h"
-#include "passphrase.h"
-#include "rand.h"
-
-#include "blowfish-cbc.h"
-#include "rmd160.h"
-#include "rmd160-mgf.h"
-#include "rmd160-hmac.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- Format --- *
- *
- * Choose a random 160-bit string %$R$%. Take the passphrase %$P$%, and
- * the message %$m$%. Now, compute %$K_E \cat K_T = H(R \cat P)$%,
- * %$y_0 = E_{K_E}(m)$% and %$\tau = T_{K_T}(y_0)$%. The ciphertext is
- * %$y = N \cat \tau \cat y_0$%.
- *
- * This is not the original format. The original format was insecure, and
- * has been replaced incompatibly.
- */
-
-/* --- @key_lock@ --- *
- *
- * Arguments: @key_data **kt@ = where to store the destination pointer
- * @key_data *k@ = source key data block or null to use @*kt@
- * @const void *e@ = secret to encrypt key with
- * @size_t esz@ = size of the secret
- *
- * Returns: ---
- *
- * Use: Encrypts a key data block using a secret.
- */
-
-void key_lock(key_data **kt, key_data *k, const void *e, size_t esz)
-{
- dstr d = DSTR_INIT;
- octet b[RMD160_HASHSZ * 2];
- octet *m;
- size_t msz;
- rmd160_mgfctx r;
- blowfish_cbcctx c;
- rmd160_mackey mk;
- rmd160_macctx mc;
-
- /* --- Sanity check --- */
-
- if (k) key_incref(k); else k = *kt;
- assert(((void)"Key data is already encrypted",
- (k->e & KF_ENCMASK) != KENC_ENCRYPT));
-
- /* --- Format the stuff in the buffer --- */
-
- DENSURE(&d, RMD160_HASHSZ * 2);
- rand_get(RAND_GLOBAL, d.buf, RMD160_HASHSZ);
- d.len += RMD160_HASHSZ * 2;
- key_encode(k, &d, 0);
- m = (octet *)d.buf + RMD160_HASHSZ * 2;
- msz = d.len - RMD160_HASHSZ * 2;
-
- /* --- Hash the passphrase to make a key --- */
-
- rmd160_mgfkeybegin(&r);
- rmd160_mgfkeyadd(&r, d.buf, RMD160_HASHSZ);
- rmd160_mgfkeyadd(&r, e, esz);
- rmd160_mgfencrypt(&r, 0, b, sizeof(b));
- BURN(r);
-
- /* --- Encrypt the plaintext --- */
-
- blowfish_cbcinit(&c, b, RMD160_HASHSZ, 0);
- blowfish_cbcencrypt(&c, m, m, msz);
- BURN(c);
-
- /* --- MAC the ciphertext --- */
-
- rmd160_hmacinit(&mk, b + RMD160_HASHSZ, RMD160_HASHSZ);
- rmd160_macinit(&mc, &mk);
- rmd160_machash(&mc, m, msz);
- rmd160_macdone(&mc, d.buf + RMD160_HASHSZ);
- BURN(mk);
- BURN(mc);
-
- /* --- Done --- */
-
- BURN(b);
- *kt = key_newencrypted(0, d.buf, d.len);
- key_drop(k);
- dstr_destroy(&d);
-}
-
-/* --- @key_unlock@ --- *
- *
- * Arguments: @key_data **kt@ = where to store the destination pointer
- * @key_data *k@ = source key data block or null to use @*kt@
- * @const void *e@ = secret to decrypt the block with
- * @size_t esz@ = size of the secret
- *
- * Returns: Zero for success, or a @KERR_@ error code.
- *
- * Use: Unlocks a key using a secret.
- */
-
-int key_unlock(key_data **kt, key_data *k, const void *e, size_t esz)
-{
- octet b[RMD160_HASHSZ * 2];
- octet *p = 0;
- int rc;
- int drop = 0;
- key_data *kd;
- rmd160_mgfctx r;
- blowfish_cbcctx c;
- rmd160_mackey mk;
- rmd160_macctx mc;
- size_t sz;
-
- /* --- Sanity check --- */
-
- if (!k) { k = *kt; drop = 1; }
- assert(((void)"Key data isn't encrypted",
- (k->e & KF_ENCMASK) == KENC_ENCRYPT));
-
- /* --- Check the size --- */
-
- if (k->u.k.sz < RMD160_HASHSZ * 2)
- return (KERR_MALFORMED);
- sz = k->u.k.sz - RMD160_HASHSZ * 2;
-
- /* --- Hash the passphrase to make a key --- */
-
- rmd160_mgfkeybegin(&r);
- rmd160_mgfkeyadd(&r, k->u.k.k, RMD160_HASHSZ);
- rmd160_mgfkeyadd(&r, e, esz);
- rmd160_mgfencrypt(&r, 0, b, sizeof(b));
- BURN(r);
-
- /* --- Verify the MAC --- */
-
- rmd160_hmacinit(&mk, b + RMD160_HASHSZ, RMD160_HASHSZ);
- rmd160_macinit(&mc, &mk);
- rmd160_machash(&mc, k->u.k.k + RMD160_HASHSZ * 2, sz);
- rmd160_macdone(&mc, b + RMD160_HASHSZ);
- if (memcmp(b + RMD160_HASHSZ, k->u.k.k + RMD160_HASHSZ,
- RMD160_HASHSZ) != 0) {
- rc = KERR_BADPASS;
- goto fail;
- }
- BURN(mk);
- BURN(mc);
-
- /* --- Allocate a destination buffer --- */
-
- p = xmalloc(sz);
-
- /* --- Decrypt the key data --- */
-
- blowfish_cbcinit(&c, b, RMD160_HASHSZ, 0);
- blowfish_cbcdecrypt(&c, k->u.k.k + RMD160_HASHSZ * 2, p, sz);
- BURN(c);
-
- /* --- Decode the key data into the destination buffer --- */
-
- if ((kd = key_decode(p, sz)) == 0) {
- rc = KERR_MALFORMED;
- goto fail;
- }
- *kt = kd;
-
- /* --- Done --- */
-
- xfree(p);
- if (drop) key_drop(k);
- return (0);
-
- /* --- Tidy up if things went wrong --- */
-
-fail:
- BURN(b);
- xfree(p);
- return (rc);
-}
-
-/* --- @key_plock@ --- *
- *
- * Arguments: @key_data **kt@ = where to store the destination pointer
- * @key_data *k@ = source key data block or null to use @*kt@
- * @const char *tag@ = tag to use for passphrase
- *
- * Returns: Zero if successful, a @KERR@ error code on failure.
- *
- * Use: Locks a key by encrypting it with a passphrase.
- */
-
-int key_plock(key_data **kt, key_data *k, const char *tag)
-{
- char buf[256];
-
- if (passphrase_read(tag, PMODE_VERIFY, buf, sizeof(buf)))
- return (KERR_IO);
- key_lock(kt, k, buf, strlen(buf));
- BURN(buf);
- return (0);
-}
-
-/* --- @key_punlock@ --- *
- *
- * Arguments: @key_data **kt@ = where to store the destination pointer
- * @key_data *k@ = source key data block or null to use @*kt@
- * @const char *tag@ = tag to use for passphrase
- *
- * Returns: Zero if it worked, a @KERR_@ error code on failure.
- *
- * Use: Unlocks a passphrase-locked key.
- */
-
-int key_punlock(key_data **kt, key_data *k, const char *tag)
-{
- char buf[256];
- int rc;
-
- if (passphrase_read(tag, PMODE_READ, buf, sizeof(buf)))
- return (KERR_IO);
- rc = key_unlock(kt, k, buf, strlen(buf));
- BURN(buf);
- if (rc == KERR_BADPASS || !k)
- passphrase_cancel(tag);
- return (rc);
-}
-
-/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff