gpg: Improve function documentation and some comments.
[gnupg.git] / g10 / seckey-cert.c
index a8fae04..02dbb48 100644 (file)
@@ -1,11 +1,12 @@
-/* seckey-cert.c -  secret key certificate packet handling
- *     Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+/* seckey-cert.c - Not anymore used
+ * Copyright (C) 1998, 1999, 2000, 2001, 2002,
+ *               2006, 2009 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
+ * 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,
  * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+#error Not anymore used - only kept for reference in the repository.
+
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+
+#include "gpg.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"
-
+#include "pkglue.h"
 
 static int
-do_check( PKT_secret_key *sk )
+xxxx_do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
+               int *canceled )
 {
+    gpg_error_t err;
     byte *buffer;
     u16 csum=0;
     int i, res;
-    unsigned nbytes;
+    size_t 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;
+       gcry_cipher_hd_t cipher_hd=NULL;
        PKT_secret_key *save_sk;
 
+       if( sk->protect.s2k.mode == 1001 ) {
+           log_info(_("secret key parts are not available\n"));
+           return GPG_ERR_UNUSABLE_SECKEY;
+       }
        if( sk->protect.algo == CIPHER_ALGO_NONE )
            BUG();
-       if( check_cipher_algo( sk->protect.algo ) ) {
-           log_info(_("protection algorithm %d is not supported\n"),
-                       sk->protect.algo );
-           return G10ERR_CIPHER_ALGO;
+       if( openpgp_cipher_test_algo( sk->protect.algo ) ) {
+           log_info(_("protection algorithm %d%s is not supported\n"),
+                       sk->protect.algo,sk->protect.algo==1?" (IDEA)":"" );
+           return GPG_ERR_CIPHER_ALGO;
        }
+       if(gcry_md_test_algo (sk->protect.s2k.hash_algo))
+         {
+           log_info(_("protection digest %d is not supported\n"),
+                    sk->protect.s2k.hash_algo);
+           return GPG_ERR_DIGEST_ALGO;
+         }
        keyid_from_sk( sk, keyid );
        keyid[2] = keyid[3] = 0;
-       if( !sk->is_primary ) {
-           PKT_secret_key *sk2 = m_alloc_clear( sizeof *sk2 );
-           if( !get_primary_seckey( sk2, keyid ) )
-               keyid_from_sk( sk2, keyid+2 );
-           free_secret_key( sk2 );
-       }
+       if (!sk->flags.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, 0 );
-       cipher_hd = cipher_open( sk->protect.algo,
-                                CIPHER_MODE_AUTO_CFB, 1);
-       cipher_setkey( cipher_hd, dek->key, dek->keylen );
-       m_free(dek);
+                                &sk->protect.s2k, mode,
+                                 tryagain_text, canceled );
+        if (!dek && canceled && *canceled)
+           return GPG_ERR_CANCELED;
+
+
+       err = openpgp_cipher_open (&cipher_hd, sk->protect.algo,
+                                  GCRY_CIPHER_MODE_CFB,
+                                  (GCRY_CIPHER_SECURE
+                                   | (sk->protect.algo >= 100 ?
+                                      0 : GCRY_CIPHER_ENABLE_SYNC)));
+        if (err)
+          log_fatal ("cipher open failed: %s\n", gpg_strerror (err) );
+
+       err = gcry_cipher_setkey (cipher_hd, dek->key, dek->keylen);
+        if (err)
+          log_fatal ("set key failed: %s\n", gpg_strerror (err) );
+
+       xfree(dek);
        save_sk = copy_secret_key( NULL, sk );
-       cipher_setiv( cipher_hd, sk->protect.iv, sk->protect.ivlen );
+
+       gcry_cipher_setiv ( cipher_hd, sk->protect.iv, sk->protect.ivlen );
+
        csum = 0;
        if( sk->version >= 4 ) {
-           int ndata;
+            int ndata;
+           unsigned int ndatabits;
            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 );
-           data = m_alloc_secure( ndata );
-           cipher_decrypt( cipher_hd, data, p, ndata );
-           mpi_free( sk->skey[i] ); sk->skey[i] = NULL ;
+
+            assert ( gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE ));
+            p = gcry_mpi_get_opaque ( sk->skey[i], &ndatabits );
+            ndata = (ndatabits+7)/8;
+
+            if ( ndata > 1 )
+              csumc = buf16_to_u16 (p+ndata-2);
+           data = xmalloc_secure ( ndata );
+           gcry_cipher_decrypt ( cipher_hd, data, ndata, p, ndata );
+           gcry_mpi_release (sk->skey[i]); sk->skey[i] = NULL ;
+
            p = data;
-           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];
-           }
-           /* must check it here otherwise the mpi_read_xx would fail
-            * because the length das an abritary 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 );
-                   ndata -= nbytes;
-                   p += nbytes;
-               }
-           }
-           m_free(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 {
+                    gcry_md_hd_t h;
+
+                    if ( gcry_md_open (&h, DIGEST_ALGO_SHA1, 1))
+                        BUG(); /* Algo not available. */
+                    gcry_md_write (h, data, ndata - 20);
+                    gcry_md_final (h);
+                    if (!memcmp (gcry_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);
+                      }
+                    gcry_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++ ) {
+                    if ( gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP,
+                                        p, ndata, &nbytes))
+                      {
+                        /* 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++ ) {
-               buffer = mpi_get_secure_buffer( sk->skey[i], &nbytes, NULL );
-               cipher_sync( cipher_hd );
-               assert( mpi_is_protected(sk->skey[i]) );
-               cipher_decrypt( cipher_hd, buffer, buffer, nbytes );
-               mpi_set_buffer( sk->skey[i], buffer, nbytes, 0 );
-               mpi_clear_protect_flag( sk->skey[i] );
-               csum += checksum_mpi( sk->skey[i] );
-               m_free( buffer );
-           }
-           if( opt.emulate_bugs & EMUBUG_GPGCHKSUM ) {
-              csum = sk->csum;
+                byte *p;
+                size_t ndata;
+                unsigned int ndatabits;
+
+                assert (gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE));
+                p = gcry_mpi_get_opaque (sk->skey[i], &ndatabits);
+                ndata = (ndatabits+7)/8;
+                assert (ndata >= 2);
+                assert (ndata == ((p[0] << 8 | p[1]) + 7)/8 + 2);
+                buffer = xmalloc_secure (ndata);
+               gcry_cipher_sync (cipher_hd);
+                buffer[0] = p[0];
+                buffer[1] = p[1];
+                gcry_cipher_decrypt (cipher_hd, buffer+2, ndata-2,
+                                     p+2, ndata-2);
+                csum += checksum (buffer, ndata);
+                gcry_mpi_release (sk->skey[i]);
+
+               err = gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP,
+                                    buffer, ndata, &ndata );
+               xfree (buffer);
+                if (err)
+                  {
+                    /* 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 */
+       gcry_cipher_close ( cipher_hd );
+
+       /* Now let's see whether we have used the correct 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;
+           return gpg_error (GPG_ERR_BAD_PASSPHRASE);
        }
-       /* the checksum may fail, so we also check the key itself */
-       res = pubkey_check_secret_key( sk->pubkey_algo, sk->skey );
+
+       /* The checksum may fail, so we also check the key itself. */
+       res = pk_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;
+           return gpg_error (GPG_ERR_BAD_PASSPHRASE);
        }
        free_secret_key( save_sk );
        sk->is_protected = 0;
@@ -145,158 +249,8 @@ do_check( PKT_secret_key *sk )
            csum += checksum_mpi( sk->skey[i] );
        }
        if( csum != sk->csum )
-           return G10ERR_CHECKSUM;
+           return GPG_ERR_CHECKSUM;
     }
 
     return 0;
 }
-
-
-
-/****************
- * Check the secret key
- * Ask up to 3 (or n) times for a correct passphrase
- */
-int
-check_secret_key( PKT_secret_key *sk, int n )
-{
-    int rc = G10ERR_BAD_PASS;
-    int i;
-
-    if( n < 1 )
-       n = opt.batch? 1 : 3; /* use the default value */
-
-    for(i=0; i < n && rc == G10ERR_BAD_PASS; i++ ) {
-       if( i )
-           log_info(_("Invalid passphrase; please try again ...\n"));
-       rc = do_check( sk );
-       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() )
-           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
- */
-int
-is_secret_key_protected( PKT_secret_key *sk )
-{
-    return sk->is_protected? 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 ) {
-             #define NMPIS (PUBKEY_MAX_NSKEY - PUBKEY_MAX_NPKEY)
-               byte *bufarr[NMPIS];
-               unsigned narr[NMPIS];
-               unsigned nbits[NMPIS];
-               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 < NMPIS; j++ )
-                   bufarr[j] = NULL;
-               ndata += 2; /* for checksum */
-
-               data = m_alloc_secure( ndata );
-               p = data;
-               for(j=0; j < NMPIS && bufarr[j]; j++ ) {
-                   p[0] = nbits[j] >> 8 ;
-                   p[1] = nbits[j];
-                   p += 2;
-                   memcpy(p, bufarr[j], narr[j] );
-                   p += narr[j];
-                   m_free(bufarr[j]);
-               }
-             #undef NMPIS
-               csum = checksum( data, ndata-2);
-               sk->csum = csum;
-               *p++ =  csum >> 8;
-               *p++ =  csum;
-               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 {
-               /* NOTE: we always recalculate the checksum because there
-                * are some test releases which calculated it wrong */
-               csum = 0;
-               for(i=pubkey_get_npkey(sk->pubkey_algo);
-                       i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
-                   csum += checksum_mpi_counted_nbits( sk->skey[i] );
-                   buffer = mpi_get_buffer( sk->skey[i], &nbytes, NULL );
-                   cipher_sync( cipher_hd );
-                   assert( !mpi_is_protected(sk->skey[i]) );
-                   cipher_encrypt( cipher_hd, buffer, buffer, nbytes );
-                   mpi_set_buffer( sk->skey[i], buffer, nbytes, 0 );
-                   mpi_set_protect_flag( sk->skey[i] );
-                   m_free( buffer );
-               }
-               sk->csum = csum;
-           }
-           sk->is_protected = 1;
-           cipher_close( cipher_hd );
-       }
-    }
-    return rc;
-}
-