Update head to match stable 1.0
[gnupg.git] / g10 / seckey-cert.c
index f963fd6..01f4c7b 100644 (file)
@@ -1,14 +1,14 @@
-/* seckey-cert.c -  secret key certifucate packet handling
- *     Copyright (C) 1998 Free Software Foundation, Inc.
+/* 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.
+ * This file is part of GnuPG.
  *
- * GNUPG is free software; you can redistribute it and/or modify
+ * 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,
+ * 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.
 #include "mpi.h"
 #include "keydb.h"
 #include "cipher.h"
-
-#if  BLOWFISH_BLOCKSIZE != 8
-  #error unsupportted blocksize
-#endif
-
-static u16
-checksum_u16( unsigned n )
-{
-    u16 a;
-
-    a  = (n >> 8) & 0xff;
-    a |= n & 0xff;
-    return a;
-}
-
-static u16
-checksum( byte *p, unsigned n )
-{
-    u16 a;
-
-    for(a=0; n; n-- )
-       a += *p++;
-    return a;
-}
-
+#include "main.h"
+#include "options.h"
+#include "i18n.h"
+#include "status.h"
 
 
 static int
-check_elg( PKT_secret_cert *cert )
+do_check( PKT_secret_key *sk, const char *tryagain_text )
 {
     byte *buffer;
     u16 csum=0;
-    int res;
+    int i, res;
     unsigned nbytes;
-    u32 keyid[2];
-    ELG_secret_key skey;
-    char save_iv[8];
 
-    if( cert->d.elg.is_protected ) { /* remove the protection */
+    if( sk->is_protected ) { /* remove the protection */
        DEK *dek = NULL;
-       MPI test_x;
-       BLOWFISH_context *blowfish_ctx=NULL;
+       u32 keyid[4]; /* 4! because we need two of them */
+       CIPHER_HANDLE cipher_hd=NULL;
+       PKT_secret_key *save_sk;
 
-       switch( cert->d.elg.protect.algo ) {
-         case CIPHER_ALGO_NONE: BUG(); break;
-         case CIPHER_ALGO_BLOWFISH:
-           keyid_from_skc( cert, keyid );
-           if( cert->d.elg.protect.s2k == 1
-               || cert->d.elg.protect.s2k == 3 )
-               dek = get_passphrase_hash( keyid, NULL,
-                                                cert->d.elg.protect.salt );
-           else
-               dek = get_passphrase_hash( keyid, NULL, NULL );
-
-           blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
-           blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
-           m_free(dek); /* pw is in secure memory, so m_free() burns it */
-           blowfish_setiv( blowfish_ctx, NULL );
-           memcpy(save_iv, cert->d.elg.protect.iv, 8 );
-           blowfish_decode_cfb( blowfish_ctx,
-                                cert->d.elg.protect.iv,
-                                cert->d.elg.protect.iv, 8 );
-           mpi_set_secure(cert->d.elg.x );
-           /*fixme: maybe it is better to set the buffer secure with a
-            * new get_buffer_secure() function */
-           buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
-           csum = checksum_u16( nbytes*8 );
-           blowfish_decode_cfb( blowfish_ctx, buffer, buffer, nbytes );
-           csum += checksum( buffer, nbytes );
-           test_x = mpi_alloc_secure( mpi_get_nlimbs(cert->d.elg.x) );
-           mpi_set_buffer( test_x, buffer, nbytes, 0 );
-           m_free( buffer );
-           m_free( blowfish_ctx );
-           /* now let's see wether we have used the right passphrase */
-           if( csum != cert->d.elg.csum ) {
-               mpi_free(test_x);
-               memcpy( cert->d.elg.protect.iv, save_iv, 8 );
-               return G10ERR_BAD_PASS;
+       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)":"" );
+           idea_cipher_warn(0);
+           return G10ERR_CIPHER_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, 0, tryagain_text );
+       cipher_hd = cipher_open( sk->protect.algo,
+                                CIPHER_MODE_AUTO_CFB, 1);
+       cipher_setkey( cipher_hd, dek->key, dek->keylen );
+       m_free(dek);
+       save_sk = copy_secret_key( NULL, sk );
+       cipher_setiv( cipher_hd, sk->protect.iv, sk->protect.ivlen );
+       csum = 0;
+       if( sk->version >= 4 ) {
+           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 = m_alloc_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 );
+                    ndata -= nbytes;
+                    p += nbytes;
+                }
+                /* Note: at this point ndata should be 2 for a simple
+                   checksum or 20 for the sha1 digest */
+            }
+           m_free(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 );
            }
-
-           skey.p = cert->d.elg.p;
-           skey.g = cert->d.elg.g;
-           skey.y = cert->d.elg.y;
-           skey.x = test_x;
-           res = elg_check_secret_key( &skey );
-           memset( &skey, 0, sizeof skey );
-           if( !res ) {
-               mpi_free(test_x);
-               memcpy( cert->d.elg.protect.iv, save_iv, 8 );
-               return G10ERR_BAD_PASS;
+           if( opt.emulate_bugs & EMUBUG_GPGCHKSUM ) {
+              csum = sk->csum;
            }
-           mpi_set(cert->d.elg.x, test_x);
-           mpi_free(test_x);
-           cert->d.elg.is_protected = 0;
-           break;
-
-         default:
-           return G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
        }
-    }
-    else { /* not protected */
-       buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
-       csum = checksum_u16( nbytes*8 );
-       csum += checksum( buffer, nbytes );
-       m_free( buffer );
-       if( csum != cert->d.elg.csum )
-           return G10ERR_CHECKSUM;
-    }
-
-    return 0;
-}
-
-static int
-protect_elg( PKT_secret_cert *cert, DEK *dek )
-{
-    byte *buffer;
-    unsigned nbytes;
-
-    if( !cert->d.elg.is_protected ) { /* add the protection */
-       BLOWFISH_context *blowfish_ctx=NULL;
-
-       switch( cert->d.elg.protect.algo ) {
-         case CIPHER_ALGO_NONE: BUG(); break;
-         case CIPHER_ALGO_BLOWFISH:
-           blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
-           blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
-           blowfish_setiv( blowfish_ctx, NULL );
-           blowfish_encode_cfb( blowfish_ctx,
-                                cert->d.elg.protect.iv,
-                                cert->d.elg.protect.iv, 8 );
-           buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
-           blowfish_encode_cfb( blowfish_ctx, buffer, buffer, nbytes );
-           mpi_set_buffer( cert->d.elg.x, buffer, nbytes, 0 );
-           m_free( buffer );
-           m_free( blowfish_ctx );
-           cert->d.elg.is_protected = 1;
-           break;
-
-         default:
-           return G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
+       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, sk->pubkey_algo );
+           free_secret_key( save_sk );
+           return G10ERR_BAD_PASS;
        }
-    }
-    return 0;
-}
-
-
-#ifdef HAVE_RSA_CIPHER
-static int
-check_rsa( PKT_secret_cert *cert )
-{
-    byte *buffer;
-    u16 csum=0;
-    int res;
-    unsigned nbytes;
-    u32 keyid[2];
-    RSA_secret_key skey;
-
-    if( cert->d.rsa.is_protected ) { /* remove the protection */
-       DEK *dek = NULL;
-       BLOWFISH_context *blowfish_ctx=NULL;
-
-       switch( cert->d.rsa.protect_algo ) {
-           /* FIXME: use test variables to check for the correct key */
-         case CIPHER_ALGO_NONE: BUG(); break;
-         case CIPHER_ALGO_BLOWFISH:
-           keyid_from_skc( cert, keyid );
-           dek = get_passphrase_hash( keyid, NULL );
-           blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
-           blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
-           m_free(dek); /* pw is in secure memory, so m_free() burns it */
-           blowfish_setiv( blowfish_ctx, NULL );
-           blowfish_decode_cfb( blowfish_ctx,
-                                cert->d.rsa.protect.blowfish.iv,
-                                cert->d.rsa.protect.blowfish.iv, 8 );
-           csum = 0;
-           #define X(a) do { \
-               mpi_set_secure(cert->d.rsa.rsa_##a); \
-               buffer = mpi_get_buffer( cert->d.rsa.rsa_##a, &nbytes, NULL );\
-               csum += checksum_u16( nbytes*8 );                            \
-               blowfish_decode_cfb( blowfish_ctx, buffer, buffer, nbytes ); \
-               csum += checksum( buffer, nbytes );                          \
-               mpi_set_buffer(cert->d.rsa.rsa_##a, buffer, nbytes, 0 );     \
-               m_free( buffer );                                            \
-              } while(0)
-           X(d);
-           X(p);
-           X(q);
-           X(u);
-           #undef X
-           cert->d.rsa.is_protected = 0;
-           m_free( blowfish_ctx );
-           /* now let's see wether we have used the right passphrase */
-           if( csum != cert->d.rsa.csum )
-               return G10ERR_BAD_PASS;
-
-           skey.d = cert->d.rsa.rsa_d;
-           skey.p = cert->d.rsa.rsa_p;
-           skey.q = cert->d.rsa.rsa_q;
-           skey.u = cert->d.rsa.rsa_u;
-           res = rsa_check_secret_key( &skey );
-           memset( &skey, 0, sizeof skey );
-           if( !res )
-               return G10ERR_BAD_PASS;
-           break;
-
-         default:
-           return G10ERR_CIPHER_ALGO; /* unsupported protection algorithm */
+       /* 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, sk->pubkey_algo );
+           free_secret_key( save_sk );
+           return G10ERR_BAD_PASS;
        }
+       free_secret_key( save_sk );
+       sk->is_protected = 0;
     }
-    else { /* not protected */
-       csum =0;
-       buffer = mpi_get_buffer( cert->d.rsa.rsa_d, &nbytes, NULL );
-       csum += checksum_u16( nbytes*8 );
-       csum += checksum( buffer, nbytes );
-       m_free( buffer );
-       buffer = mpi_get_buffer( cert->d.rsa.rsa_p, &nbytes, NULL );
-       csum += checksum_u16( nbytes*8 );
-       csum += checksum( buffer, nbytes );
-       m_free( buffer );
-       buffer = mpi_get_buffer( cert->d.rsa.rsa_q, &nbytes, NULL );
-       csum += checksum_u16( nbytes*8 );
-       csum += checksum( buffer, nbytes );
-       m_free( buffer );
-       buffer = mpi_get_buffer( cert->d.rsa.rsa_u, &nbytes, NULL );
-       csum += checksum_u16( nbytes*8 );
-       csum += checksum( buffer, nbytes );
-       m_free( buffer );
-       if( csum != cert->d.rsa.csum )
+    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;
 }
-#endif /*HAVE_RSA_CIPHER*/
-
 
 
 
 /****************
- * Check the secret key certificate
- * Ask up to 3 time for a correct passphrase
+ * Check the secret key
+ * Ask up to 3 (or n) times for a correct passphrase
  */
 int
-check_secret_key( PKT_secret_cert *cert )
+check_secret_key( PKT_secret_key *sk, int n )
 {
     int rc = G10ERR_BAD_PASS;
     int i;
 
-    for(i=0; i < 3 && rc == G10ERR_BAD_PASS; i++ ) {
-       if( i )
-           log_error("Invalid passphrase; please try again ...\n");
-       if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
-           rc = check_elg( cert );
-      #ifdef HAVE_RSA_CIPHER
-       else if( cert->pubkey_algo == PUBKEY_ALGO_RSA )
-           rc = check_rsa( cert );
-      #endif
-       else
-           rc = G10ERR_PUBKEY_ALGO;
-       if( get_passphrase_fd() != -1 )
+    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++ ) {
+        const char *tryagain = NULL;
+       if (i) {
+            tryagain = _("Invalid passphrase; please try again");
+            log_info (_("%s ...\n"), tryagain);
+        }
+       rc = do_check( sk, tryagain );
+       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 wether the secret key is protected.
+ * 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_cert *cert )
+is_secret_key_protected( PKT_secret_key *sk )
 {
-    if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
-       return cert->d.elg.is_protected? cert->d.elg.protect.algo : 0;
-  #ifdef HAVE_RSA_CIPHER
-    else if( cert->pubkey_algo == PUBKEY_ALGO_RSA )
-       return cert->d.rsa.is_protected? cert->d.rsa.protect_algo : 0;
-  #endif
-    else
-       return -1; /* unsupported */
+    return sk->is_protected? sk->protect.algo : 0;
 }
 
 
+
 /****************
- * Protect the secret key certificate with the passphrase from DEK
+ * Protect the secret key with the passphrase from DEK
  */
 int
-protect_secret_key( PKT_secret_cert *cert, DEK *dek )
+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( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
-       return protect_elg( cert, dek );
-    else
-       return G10ERR_PUBKEY_ALGO;
+    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 = m_alloc_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];
+                   m_free(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 {
+               /* 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;
 }