/* keygen.c - generate a key pair * Copyright (c) 1997 by Werner Koch (dd9jn) * * This file is part of G10. * * G10 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. * * G10 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #include #include #include #include #include #include #include "util.h" #include "main.h" #include "packet.h" #include "cipher.h" #include "ttyio.h" #include "options.h" #include "keydb.h" #if 0 #define TEST_ALGO 1 #define TEST_NBITS 256 #define TEST_UID "Karl Test" #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; } static u16 checksum_mpi( MPI a ) { u16 csum; byte *buffer; unsigned nbytes; buffer = mpi_get_buffer( a, &nbytes, NULL ); csum = checksum_u16( nbytes*8 ); csum += checksum( buffer, nbytes ); m_free( buffer ); return csum; } static void write_uid( KBNODE root, const char *s ) { PACKET *pkt = m_alloc_clear(sizeof *pkt ); size_t n = strlen(s); pkt->pkttype = PKT_USER_ID; pkt->pkt.user_id = m_alloc( sizeof *pkt->pkt.user_id + n - 1 ); pkt->pkt.user_id->len = n; strcpy(pkt->pkt.user_id->name, s); add_kbnode( root, new_kbnode( pkt ) ); } static int write_selfsig( KBNODE root, KBNODE pub_root, PKT_secret_cert *skc ) { PACKET *pkt; PKT_signature *sig; PKT_user_id *uid; int rc=0; KBNODE kbctx, node; PKT_public_cert *pkc; if( opt.verbose ) log_info("writing self signature\n"); /* get the uid packet from the tree */ for( kbctx=NULL; (node=walk_kbtree( root, &kbctx)) ; ) { if( node->pkt->pkttype == PKT_USER_ID ) break; } if( !node ) log_bug(NULL); /* no user id packet in tree */ uid = node->pkt->pkt.user_id; /* get the pkc packet from the pub_tree */ for( kbctx=NULL; (node=walk_kbtree( pub_root, &kbctx)) ; ) { if( node->pkt->pkttype == PKT_PUBLIC_CERT ) break; } if( !node ) log_bug(NULL); pkc = node->pkt->pkt.public_cert; /* and make the signature */ rc = make_keysig_packet( &sig, pkc, uid, skc, 0x13, DIGEST_ALGO_RMD160 ); if( rc ) { log_error("make_keysig_packet failed: %s\n", g10_errstr(rc) ); return rc; } pkt = m_alloc_clear( sizeof *pkt ); pkt->pkttype = PKT_SIGNATURE; pkt->pkt.signature = sig; add_kbnode( root, new_kbnode( pkt ) ); return rc; } static int gen_elg(unsigned nbits, KBNODE pub_root, KBNODE sec_root, DEK *dek, PKT_secret_cert **ret_skc ) { int rc; PACKET *pkt; PKT_secret_cert *skc; PKT_public_cert *pkc; ELG_public_key pk; ELG_secret_key sk; unsigned nbytes; elg_generate( &pk, &sk, nbits ); skc = m_alloc( sizeof *skc ); pkc = m_alloc( sizeof *pkc ); skc->timestamp = pkc->timestamp = make_timestamp(); skc->valid_days = pkc->valid_days = 0; /* fixme: make it configurable*/ skc->pubkey_algo = pkc->pubkey_algo = PUBKEY_ALGO_ELGAMAL; memset(&pkc->mfx, 0, sizeof pkc->mfx); pkc->d.elg.p = pk.p; pkc->d.elg.g = pk.g; pkc->d.elg.y = pk.y; skc->d.elg.p = sk.p; skc->d.elg.g = sk.g; skc->d.elg.y = sk.y; skc->d.elg.x = sk.x; skc->d.elg.is_protected = 0; skc->d.elg.protect_algo = 0; skc->d.elg.csum = checksum_mpi( skc->d.elg.x ); /* return an unprotected version of the skc */ *ret_skc = copy_secret_cert( NULL, skc ); if( dek ) { skc->d.elg.protect_algo = CIPHER_ALGO_BLOWFISH; randomize_buffer(skc->d.elg.protect.blowfish.iv, 8, 1); rc = protect_secret_key( skc, dek ); if( rc ) { log_error("protect_secret_key failed: %s\n", g10_errstr(rc) ); free_public_cert(pkc); free_secret_cert(skc); return rc; } } pkt = m_alloc_clear(sizeof *pkt); pkt->pkttype = PKT_PUBLIC_CERT; pkt->pkt.public_cert = pkc; add_kbnode(pub_root, new_kbnode( pkt )); pkt = m_alloc_clear(sizeof *pkt); pkt->pkttype = PKT_SECRET_CERT; pkt->pkt.secret_cert = skc; add_kbnode(sec_root, new_kbnode( pkt )); return 0; } #ifdef HAVE_RSA_CIPHER static int gen_rsa(unsigned nbits, IOBUF pub_io, IOBUF sec_io, DEK *dek, PKT_public_cert **ret_pkc, PKT_secret_cert **ret_skc ) { int rc; PACKET pkt1, pkt2; PKT_secret_cert *skc; PKT_public_cert *pkc; RSA_public_key pk; RSA_secret_key sk; init_packet(&pkt1); init_packet(&pkt2); rsa_generate( &pk, &sk, nbits ); skc = m_alloc( sizeof *skc ); pkc = m_alloc( sizeof *pkc ); skc->timestamp = pkc->timestamp = make_timestamp(); skc->valid_days = pkc->valid_days = 0; /* fixme: make it configurable*/ skc->pubkey_algo = pkc->pubkey_algo = PUBKEY_ALGO_RSA; memset(&pkc->mfx, 0, sizeof pkc->mfx); pkc->d.rsa.rsa_n = pk.n; pkc->d.rsa.rsa_e = pk.e; skc->d.rsa.rsa_n = sk.n; skc->d.rsa.rsa_e = sk.e; skc->d.rsa.rsa_d = sk.d; skc->d.rsa.rsa_p = sk.p; skc->d.rsa.rsa_q = sk.q; skc->d.rsa.rsa_u = sk.u; skc->d.rsa.csum = checksum_mpi( skc->d.rsa.rsa_d ); skc->d.rsa.csum += checksum_mpi( skc->d.rsa.rsa_p ); skc->d.rsa.csum += checksum_mpi( skc->d.rsa.rsa_q ); skc->d.rsa.csum += checksum_mpi( skc->d.rsa.rsa_u ); if( !dek ) { skc->d.rsa.is_protected = 0; skc->d.rsa.protect_algo = 0; } else { skc->d.rsa.is_protected = 1; skc->d.rsa.protect_algo = CIPHER_ALGO_BLOWFISH; randomize_buffer( skc->d.rsa.protect.blowfish.iv, 8, 1); skc->d.rsa.csum += checksum( skc->d.rsa.protect.blowfish.iv, 8 ); rc = protect_secret_key( skc, dek ); if( rc ) { log_error("protect_secret_key failed: %s\n", g10_errstr(rc) ); goto leave; } } pkt1.pkttype = PKT_PUBLIC_CERT; pkt1.pkt.public_cert = pkc; pkt2.pkttype = PKT_SECRET_CERT; pkt2.pkt.secret_cert = skc; if( (rc = build_packet( pub_io, &pkt1 )) ) { log_error("build public_cert packet failed: %s\n", g10_errstr(rc) ); goto leave; } if( (rc = build_packet( sec_io, &pkt2 )) ) { log_error("build secret_cert packet failed: %s\n", g10_errstr(rc) ); goto leave; } *ret_pkc = pkt1.pkt.public_cert; pkt1.pkt.public_cert = NULL; *ret_skc = pkt1.pkt.secret_cert; pkt1.pkt.secret_cert = NULL; leave: free_packet(&pkt1); free_packet(&pkt2); return rc; } #endif /*HAVE_RSA_CIPHER*/ static int gen_dsa(unsigned nbits, KBNODE pub_root, KBNODE sec_root, DEK *dek, PKT_secret_cert **ret_skc ) { return G10ERR_GENERAL; } /**************** * Generate a keypair */ void generate_keypair() { char *answer; unsigned nbits; char *pub_fname = NULL; char *sec_fname = NULL; char *uid = NULL; IOBUF pub_io = NULL; IOBUF sec_io = NULL; KBNODE pub_root = NULL; KBNODE sec_root = NULL; PKT_secret_cert *skc = NULL; DEK *dek = NULL; int rc; int algo; const char *algo_name; #ifndef TEST_ALGO if( opt.batch || opt.answer_yes || opt.answer_no ) log_fatal("Key generation can only be used in interactive mode\n"); tty_printf("Please select the algorithm to use:\n" " (1) ElGamal is the suggested one.\n" #ifdef HAVE_RSA_CIPHER " (2) RSA cannot be used in the U.S.\n" #endif " (3) DSA can only be used for signatures.\n" ); #endif for(;;) { #ifdef TEST_ALGO algo = TEST_ALGO; #else answer = tty_get("Your selection? (1" #ifdef HAVE_RSA_CIPHER ",2" #endif ",3) "); tty_kill_prompt(); algo = *answer? atoi(answer): 1; m_free(answer); #endif if( algo == 1 ) { algo = PUBKEY_ALGO_ELGAMAL; algo_name = "ElGamal"; break; } #ifdef HAVE_RSA_CIPHER else if( algo == 2 ) { algo = PUBKEY_ALGO_RSA; algo_name = "RSA"; break; } #endif else if( algo == 3 ) { algo = PUBKEY_ALGO_DSA; algo_name = "DSA"; tty_printf("Sorry; DSA is not yet supported.\n"); } } tty_printf("About to generate a new %s keypair.\n" #ifndef TEST_NBITS " minimum keysize is 768 bits\n" " default keysize is 1024 bits\n" " highest suggested keysize is 2048 bits\n" #endif , algo_name ); for(;;) { #ifdef TEST_NBITS nbits = TEST_NBITS; #else answer = tty_get("What keysize do you want? (1024) "); tty_kill_prompt(); nbits = *answer? atoi(answer): 1024; m_free(answer); #endif if( algo == PUBKEY_ALGO_DSA && (nbits < 512 || nbits > 1024) ) tty_printf("DSA does only allow keysizes from 512 to 1024\n"); else if( nbits < 768 ) tty_printf("keysize too small; 768 is smallest value allowed.\n"); else if( nbits > 2048 ) { tty_printf("Keysizes larger than 2048 are not suggested, because " "computations take REALLY long!\n"); answer = tty_get("Are you sure, that you want this keysize? "); tty_kill_prompt(); if( answer_is_yes(answer) ) { m_free(answer); tty_printf("Okay, but keep in mind that your monitor " "and keyboard radiation is also very vulnerable " "to attacks!\n"); break; } m_free(answer); } else break; } tty_printf("Requested keysize is %u bits\n", nbits ); if( algo == PUBKEY_ALGO_DSA && (nbits % 64) ) { nbits = ((nbits + 63) / 64) * 64; tty_printf("rounded up to %u bits\n", nbits ); } else if( (nbits % 32) ) { nbits = ((nbits + 31) / 32) * 32; tty_printf("rounded up to %u bits\n", nbits ); } #ifdef TEST_UID uid = m_alloc(strlen(TEST_UID)+1); strcpy(uid, TEST_UID); #else tty_printf( "\nYou need a User-ID to identify your key; please use your name and your\n" "email address in this suggested format:\n" " \"Heinrich Heine \n" ); uid = NULL; for(;;) { m_free(uid); tty_printf("\n"); uid = tty_get("Your User-ID: "); tty_kill_prompt(); if( strlen(uid) < 5 ) tty_printf("Please enter a string of at least 5 characters\n"); else { tty_printf("You selected this USER-ID:\n \"%s\"\n\n", uid); answer = tty_get("Is this correct? "); tty_kill_prompt(); if( answer_is_yes(answer) ) { m_free(answer); break; } m_free(answer); } } #endif tty_printf( "You need a Passphrase to protect your secret key.\n\n" ); dek = m_alloc_secure( sizeof *dek ); for(;;) { dek->algo = CIPHER_ALGO_BLOWFISH; rc = make_dek_from_passphrase( dek , 2 ); if( rc == -1 ) { m_free(dek); dek = NULL; tty_printf( "You don't what a passphrase - this is probably a *bad* idea!\n" "I will do it anyway. You can change your passphrase at anytime,\n" "using this program with the option \"--change-passphrase\"\n\n" ); break; } else if( rc == G10ERR_PASSPHRASE ) { tty_printf("passphrase not correctly repeated; try again.\n"); } else if( rc ) { m_free(dek); dek = NULL; m_free(uid); log_error("Error getting the passphrase: %s\n", g10_errstr(rc) ); return; } else break; /* okay */ } /* now check wether we a are allowed to write to the keyrings */ pub_fname = make_filename("~/.g10", "pubring.g10", NULL ); sec_fname = make_filename("~/.g10", "secring.g10", NULL ); if( opt.verbose ) { tty_printf("writing public certificate to '%s'\n", pub_fname ); tty_printf("writing secret certificate to '%s'\n", sec_fname ); } /* we create the packets as a tree of kbnodes. Because the structure * we create is known in advance we simply generate a linked list * The first packet is a comment packet, followed by the userid and * the self signature. */ pub_root = make_comment_node("#created by G10 pre-release " VERSION ); sec_root = make_comment_node("#created by G10 pre-release " VERSION ); tty_printf( "We need to generate a lot of random bytes. It is a good idea to perform\n" "some other action (work in another window, move the mouse, utilize the\n" "network and the disks) during the prime generation; this gives the random\n" "number generator a better chance to gain enough entropy.\n" ); if( algo == PUBKEY_ALGO_ELGAMAL ) rc = gen_elg(nbits, pub_root, sec_root, dek, &skc ); #ifdef HAVE_RSA_CIPHER else if( algo == PUBKEY_ALGO_RSA ) rc = gen_rsa(nbits, pub_io, sec_io, dek, &skc ); #endif else if( algo == PUBKEY_ALGO_DSA ) rc = gen_dsa(nbits, pub_root, sec_root, dek, &skc ); else log_bug(NULL); if( !rc ) write_uid(pub_root, uid ); if( !rc ) write_uid(sec_root, uid ); if( !rc ) rc = write_selfsig(pub_root, pub_root, skc); if( !rc ) rc = write_selfsig(sec_root, pub_root, skc); if( !rc ) { KBPOS pub_kbpos; KBPOS sec_kbpos; int rc1 = -1; int rc2 = -1; /* we can now write the certificates */ /* FIXME: should we check wether the user-id already exists? */ if( get_keyblock_handle( pub_fname, &pub_kbpos ) ) { if( add_keyblock_resource( pub_fname, 1 ) ) { log_error("can add keyblock file '%s'\n", pub_fname ); rc = G10ERR_CREATE_FILE; } else if( get_keyblock_handle( pub_fname, &pub_kbpos ) ) { log_error("can get keyblock handle for '%s'\n", pub_fname ); rc = G10ERR_CREATE_FILE; } } if( rc ) ; else if( get_keyblock_handle( sec_fname, &sec_kbpos ) ) { if( add_keyblock_resource( sec_fname, 1 ) ) { log_error("can add keyblock file '%s'\n", sec_fname ); rc = G10ERR_CREATE_FILE; } else if( get_keyblock_handle( sec_fname, &sec_kbpos ) ) { log_error("can get keyblock handle for '%s'\n", sec_fname ); rc = G10ERR_CREATE_FILE; } } if( rc ) ; else if( (rc=rc1=lock_keyblock( &pub_kbpos )) ) log_error("can't lock public keyring: %s\n", g10_errstr(rc) ); else if( (rc=rc2=lock_keyblock( &sec_kbpos )) ) log_error("can't lock secret keyring: %s\n", g10_errstr(rc) ); else if( (rc=insert_keyblock( &pub_kbpos, pub_root )) ) log_error("can't write public key: %s\n", g10_errstr(rc) ); else if( (rc=insert_keyblock( &sec_kbpos, sec_root )) ) log_error("can't write secret key: %s\n", g10_errstr(rc) ); else { tty_printf("public and secret key created and signed.\n" ); } if( !rc1 ) unlock_keyblock( &pub_kbpos ); if( !rc2 ) unlock_keyblock( &sec_kbpos ); } if( rc ) tty_printf("Key generation failed: %s\n", g10_errstr(rc) ); release_kbnode( pub_root ); release_kbnode( sec_root ); if( skc ) /* the unprotected secret certificate */ free_secret_cert(skc); m_free(uid); m_free(dek); m_free(pub_fname); m_free(sec_fname); }