summaryrefslogtreecommitdiff
path: root/g10/seckey-cert.c
diff options
context:
space:
mode:
Diffstat (limited to 'g10/seckey-cert.c')
-rw-r--r--g10/seckey-cert.c427
1 files changed, 427 insertions, 0 deletions
diff --git a/g10/seckey-cert.c b/g10/seckey-cert.c
new file mode 100644
index 0000000..79cf22a
--- /dev/null
+++ b/g10/seckey-cert.c
@@ -0,0 +1,427 @@
+/* seckey-cert.c - secret key certificate packet handling
+ * Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include "util.h"
+#include "memory.h"
+#include "packet.h"
+#include "mpi.h"
+#include "keydb.h"
+#include "cipher.h"
+#include "main.h"
+#include "options.h"
+#include "i18n.h"
+#include "status.h"
+
+
+static int
+do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
+ int *canceled )
+{
+ byte *buffer;
+ u16 csum=0;
+ int i, res;
+ unsigned nbytes;
+
+ if( sk->is_protected ) { /* remove the protection */
+ DEK *dek = NULL;
+ u32 keyid[4]; /* 4! because we need two of them */
+ CIPHER_HANDLE cipher_hd=NULL;
+ PKT_secret_key *save_sk;
+
+ if( sk->protect.s2k.mode == 1001 ) {
+ log_info(_("secret key parts are not available\n"));
+ return G10ERR_GENERAL;
+ }
+ if( sk->protect.algo == CIPHER_ALGO_NONE )
+ BUG();
+ if( check_cipher_algo( sk->protect.algo ) ) {
+ log_info(_("protection algorithm %d%s is not supported\n"),
+ sk->protect.algo,sk->protect.algo==1?" (IDEA)":"" );
+ if (sk->protect.algo==CIPHER_ALGO_IDEA)
+ {
+ write_status (STATUS_RSA_OR_IDEA);
+ idea_cipher_warn (0);
+ }
+ return G10ERR_CIPHER_ALGO;
+ }
+ if(check_digest_algo(sk->protect.s2k.hash_algo))
+ {
+ log_info(_("protection digest %d is not supported\n"),
+ sk->protect.s2k.hash_algo);
+ return G10ERR_DIGEST_ALGO;
+ }
+ keyid_from_sk( sk, keyid );
+ keyid[2] = keyid[3] = 0;
+ if( !sk->is_primary ) {
+ keyid[2] = sk->main_keyid[0];
+ keyid[3] = sk->main_keyid[1];
+ }
+ dek = passphrase_to_dek( keyid, sk->pubkey_algo, sk->protect.algo,
+ &sk->protect.s2k, mode,
+ tryagain_text, canceled );
+ if (!dek && canceled && *canceled)
+ return G10ERR_GENERAL;
+
+ cipher_hd = cipher_open( sk->protect.algo,
+ CIPHER_MODE_AUTO_CFB, 1);
+ cipher_setkey( cipher_hd, dek->key, dek->keylen );
+ xfree(dek);
+ save_sk = copy_secret_key( NULL, sk );
+ cipher_setiv( cipher_hd, sk->protect.iv, sk->protect.ivlen );
+ csum = 0;
+ if( sk->version >= 4 ) {
+ unsigned int ndata;
+ byte *p, *data;
+ u16 csumc = 0;
+
+ i = pubkey_get_npkey(sk->pubkey_algo);
+ assert( mpi_is_opaque( sk->skey[i] ) );
+ p = mpi_get_opaque( sk->skey[i], &ndata );
+ if ( ndata > 1 )
+ csumc = p[ndata-2] << 8 | p[ndata-1];
+ data = xmalloc_secure( ndata );
+ cipher_decrypt( cipher_hd, data, p, ndata );
+ mpi_free( sk->skey[i] ); sk->skey[i] = NULL ;
+ p = data;
+ if (sk->protect.sha1chk) {
+ /* This is the new SHA1 checksum method to detect
+ tampering with the key as used by the Klima/Rosa
+ attack */
+ sk->csum = 0;
+ csum = 1;
+ if( ndata < 20 )
+ log_error("not enough bytes for SHA-1 checksum\n");
+ else {
+ MD_HANDLE h = md_open (DIGEST_ALGO_SHA1, 1);
+ if (!h)
+ BUG(); /* algo not available */
+ md_write (h, data, ndata - 20);
+ md_final (h);
+ if (!memcmp (md_read (h, DIGEST_ALGO_SHA1),
+ data + ndata - 20, 20) ) {
+ /* digest does match. We have to keep the old
+ style checksum in sk->csum, so that the
+ test used for unprotected keys does work.
+ This test gets used when we are adding new
+ keys. */
+ sk->csum = csum = checksum (data, ndata-20);
+ }
+ md_close (h);
+ }
+ }
+ else {
+ if( ndata < 2 ) {
+ log_error("not enough bytes for checksum\n");
+ sk->csum = 0;
+ csum = 1;
+ }
+ else {
+ csum = checksum( data, ndata-2);
+ sk->csum = data[ndata-2] << 8 | data[ndata-1];
+ if ( sk->csum != csum ) {
+ /* This is a PGP 7.0.0 workaround */
+ sk->csum = csumc; /* take the encrypted one */
+ }
+ }
+ }
+
+ /* Must check it here otherwise the mpi_read_xx would fail
+ because the length may have an arbitrary value */
+ if( sk->csum == csum ) {
+ for( ; i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
+ nbytes = ndata;
+ sk->skey[i] = mpi_read_from_buffer(p, &nbytes, 1 );
+ if (!sk->skey[i])
+ {
+ /* Checksum was okay, but not correctly
+ decrypted. */
+ sk->csum = 0;
+ csum = 1;
+ break;
+ }
+ ndata -= nbytes;
+ p += nbytes;
+ }
+ /* Note: at this point ndata should be 2 for a simple
+ checksum or 20 for the sha1 digest */
+ }
+ xfree(data);
+ }
+ else {
+ for(i=pubkey_get_npkey(sk->pubkey_algo);
+ i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
+ byte *p;
+ unsigned int ndata;
+
+ assert (mpi_is_opaque (sk->skey[i]));
+ p = mpi_get_opaque (sk->skey[i], &ndata);
+ assert (ndata >= 2);
+ assert (ndata == ((p[0] << 8 | p[1]) + 7)/8 + 2);
+ buffer = xmalloc_secure (ndata);
+ cipher_sync (cipher_hd);
+ buffer[0] = p[0];
+ buffer[1] = p[1];
+ cipher_decrypt (cipher_hd, buffer+2, p+2, ndata-2);
+ csum += checksum (buffer, ndata);
+ mpi_free (sk->skey[i]);
+ sk->skey[i] = mpi_read_from_buffer (buffer, &ndata, 1);
+ xfree (buffer);
+ if (!sk->skey[i])
+ {
+ /* Checksum was okay, but not correctly
+ decrypted. */
+ sk->csum = 0;
+ csum = 1;
+ break;
+ }
+/* csum += checksum_mpi (sk->skey[i]); */
+ }
+ }
+ cipher_close( cipher_hd );
+ /* now let's see whether we have used the right passphrase */
+ if( csum != sk->csum ) {
+ copy_secret_key( sk, save_sk );
+ passphrase_clear_cache ( keyid, NULL, sk->pubkey_algo );
+ free_secret_key( save_sk );
+ return G10ERR_BAD_PASS;
+ }
+ /* the checksum may fail, so we also check the key itself */
+ res = pubkey_check_secret_key( sk->pubkey_algo, sk->skey );
+ if( res ) {
+ copy_secret_key( sk, save_sk );
+ passphrase_clear_cache ( keyid, NULL, sk->pubkey_algo );
+ free_secret_key( save_sk );
+ return G10ERR_BAD_PASS;
+ }
+ free_secret_key( save_sk );
+ sk->is_protected = 0;
+ }
+ else { /* not protected, assume it is okay if the checksum is okay */
+ csum = 0;
+ for(i=pubkey_get_npkey(sk->pubkey_algo);
+ i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
+ csum += checksum_mpi( sk->skey[i] );
+ }
+ if( csum != sk->csum )
+ return G10ERR_CHECKSUM;
+ }
+
+ return 0;
+}
+
+
+
+/****************
+ * Check the secret key
+ * Ask up to 3 (or n) times for a correct passphrase
+ * If n is negative, disable the key info prompt and make n=abs(n)
+ */
+int
+check_secret_key( PKT_secret_key *sk, int n )
+{
+ int rc = G10ERR_BAD_PASS;
+ int i,mode;
+
+ if (sk && sk->is_protected && sk->protect.s2k.mode == 1002)
+ return 0; /* Let the card support stuff handle this. */
+
+ if(n<0)
+ {
+ n=abs(n);
+ mode=1;
+ }
+ else
+ mode=0;
+
+ if( n < 1 )
+ n = (opt.batch && !opt.use_agent)? 1 : 3; /* use the default value */
+
+ for(i=0; i < n && rc == G10ERR_BAD_PASS; i++ ) {
+ int canceled = 0;
+ const char *tryagain = NULL;
+ if (i) {
+ tryagain = N_("Invalid passphrase; please try again");
+ log_info (_("%s ...\n"), _(tryagain));
+ }
+ rc = do_check( sk, tryagain, mode, &canceled );
+ if( rc == G10ERR_BAD_PASS && is_status_enabled() ) {
+ u32 kid[2];
+ char buf[50];
+
+ keyid_from_sk( sk, kid );
+ sprintf(buf, "%08lX%08lX", (ulong)kid[0], (ulong)kid[1]);
+ write_status_text( STATUS_BAD_PASSPHRASE, buf );
+ }
+ if( have_static_passphrase() || canceled)
+ break;
+ }
+
+ if( !rc )
+ write_status( STATUS_GOOD_PASSPHRASE );
+
+ return rc;
+}
+
+/****************
+ * check whether the secret key is protected.
+ * Returns: 0 not protected, -1 on error or the protection algorithm
+ * -2 indicates a card stub.
+ * -3 indicates a not-online stub.
+ */
+int
+is_secret_key_protected( PKT_secret_key *sk )
+{
+ return sk->is_protected?
+ sk->protect.s2k.mode == 1002? -2 :
+ sk->protect.s2k.mode == 1001? -3 : sk->protect.algo : 0;
+}
+
+
+
+/****************
+ * Protect the secret key with the passphrase from DEK
+ */
+int
+protect_secret_key( PKT_secret_key *sk, DEK *dek )
+{
+ int i,j, rc = 0;
+ byte *buffer;
+ unsigned nbytes;
+ u16 csum;
+
+ if( !dek )
+ return 0;
+
+ if( !sk->is_protected ) { /* okay, apply the protection */
+ CIPHER_HANDLE cipher_hd=NULL;
+
+ if( check_cipher_algo( sk->protect.algo ) )
+ rc = G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
+ else {
+ print_cipher_algo_note( sk->protect.algo );
+ cipher_hd = cipher_open( sk->protect.algo,
+ CIPHER_MODE_AUTO_CFB, 1 );
+ if( cipher_setkey( cipher_hd, dek->key, dek->keylen ) )
+ log_info(_("WARNING: Weak key detected"
+ " - please change passphrase again.\n"));
+ sk->protect.ivlen = cipher_get_blocksize( sk->protect.algo );
+ assert( sk->protect.ivlen <= DIM(sk->protect.iv) );
+ if( sk->protect.ivlen != 8 && sk->protect.ivlen != 16 )
+ BUG(); /* yes, we are very careful */
+ randomize_buffer(sk->protect.iv, sk->protect.ivlen, 1);
+ cipher_setiv( cipher_hd, sk->protect.iv, sk->protect.ivlen );
+ if( sk->version >= 4 ) {
+ byte *bufarr[PUBKEY_MAX_NSKEY];
+ unsigned narr[PUBKEY_MAX_NSKEY];
+ unsigned nbits[PUBKEY_MAX_NSKEY];
+ int ndata=0;
+ byte *p, *data;
+
+ for(j=0, i = pubkey_get_npkey(sk->pubkey_algo);
+ i < pubkey_get_nskey(sk->pubkey_algo); i++, j++ ) {
+ assert( !mpi_is_opaque( sk->skey[i] ) );
+ bufarr[j] = mpi_get_buffer( sk->skey[i], &narr[j], NULL );
+ nbits[j] = mpi_get_nbits( sk->skey[i] );
+ ndata += narr[j] + 2;
+ }
+ for( ; j < PUBKEY_MAX_NSKEY; j++ )
+ bufarr[j] = NULL;
+ ndata += opt.simple_sk_checksum? 2 : 20; /* for checksum */
+
+ data = xmalloc_secure( ndata );
+ p = data;
+ for(j=0; j < PUBKEY_MAX_NSKEY && bufarr[j]; j++ ) {
+ p[0] = nbits[j] >> 8 ;
+ p[1] = nbits[j];
+ p += 2;
+ memcpy(p, bufarr[j], narr[j] );
+ p += narr[j];
+ xfree(bufarr[j]);
+ }
+
+ if (opt.simple_sk_checksum) {
+ log_info (_("generating the deprecated 16-bit checksum"
+ " for secret key protection\n"));
+ csum = checksum( data, ndata-2);
+ sk->csum = csum;
+ *p++ = csum >> 8;
+ *p++ = csum;
+ sk->protect.sha1chk = 0;
+ }
+ else {
+ MD_HANDLE h = md_open (DIGEST_ALGO_SHA1, 1);
+ if (!h)
+ BUG(); /* algo not available */
+ md_write (h, data, ndata - 20);
+ md_final (h);
+ memcpy (p, md_read (h, DIGEST_ALGO_SHA1), 20);
+ p += 20;
+ md_close (h);
+ sk->csum = csum = 0;
+ sk->protect.sha1chk = 1;
+ }
+ assert( p == data+ndata );
+
+ cipher_encrypt( cipher_hd, data, data, ndata );
+ for(i = pubkey_get_npkey(sk->pubkey_algo);
+ i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
+ mpi_free( sk->skey[i] );
+ sk->skey[i] = NULL;
+ }
+ i = pubkey_get_npkey(sk->pubkey_algo);
+ sk->skey[i] = mpi_set_opaque(NULL, data, ndata );
+ }
+ else {
+ csum = 0;
+ for(i=pubkey_get_npkey(sk->pubkey_algo);
+ i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
+ byte *data;
+ unsigned int nbits;
+
+ csum += checksum_mpi (sk->skey[i]);
+ buffer = mpi_get_buffer( sk->skey[i], &nbytes, NULL );
+ cipher_sync (cipher_hd);
+ assert ( !mpi_is_opaque (sk->skey[i]) );
+ data = xmalloc (nbytes+2);
+ nbits = mpi_get_nbits (sk->skey[i]);
+ assert (nbytes == (nbits + 7)/8);
+ data[0] = nbits >> 8;
+ data[1] = nbits;
+ cipher_encrypt (cipher_hd, data+2, buffer, nbytes);
+ xfree( buffer );
+
+ mpi_free (sk->skey[i]);
+ sk->skey[i] = mpi_set_opaque (NULL, data, nbytes+2);
+ }
+ sk->csum = csum;
+ }
+ sk->is_protected = 1;
+ cipher_close( cipher_hd );
+ }
+ }
+ return rc;
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 19:32:19 +0000