diff options
Diffstat (limited to 'cipher/pubkey.c')
| -rw-r--r-- | cipher/pubkey.c | 618 |
1 files changed, 618 insertions, 0 deletions
diff --git a/cipher/pubkey.c b/cipher/pubkey.c new file mode 100644 index 000000000..9136fa544 --- /dev/null +++ b/cipher/pubkey.c @@ -0,0 +1,618 @@ +/* pubkey.c - pubkey dispatcher + * Copyright (C) 1998, 1999, 2000, 2001 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <assert.h> +#include "util.h" +#include "errors.h" +#include "mpi.h" +#include "cipher.h" +#include "elgamal.h" +#include "dsa.h" +#include "rsa.h" +#include "dynload.h" + + +#define TABLE_SIZE 10 + +struct pubkey_table_s { + const char *name; + int algo; + int npkey; + int nskey; + int nenc; + int nsig; + int use; + int (*generate)( int algo, unsigned nbits, MPI *skey, MPI **retfactors ); + int (*check_secret_key)( int algo, MPI *skey ); + int (*encrypt)( int algo, MPI *resarr, MPI data, MPI *pkey ); + int (*decrypt)( int algo, MPI *result, MPI *data, MPI *skey ); + int (*sign)( int algo, MPI *resarr, MPI data, MPI *skey ); + int (*verify)( int algo, MPI hash, MPI *data, MPI *pkey, + int (*cmp)(void *, MPI), void *opaquev ); + unsigned (*get_nbits)( int algo, MPI *pkey ); +}; + +static struct pubkey_table_s pubkey_table[TABLE_SIZE]; +static int disabled_algos[TABLE_SIZE]; + + +static int +dummy_generate( int algo, unsigned nbits, MPI *skey, MPI **retfactors ) +{ log_bug("no generate() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static int +dummy_check_secret_key( int algo, MPI *skey ) +{ log_bug("no check_secret_key() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static int +dummy_encrypt( int algo, MPI *resarr, MPI data, MPI *pkey ) +{ log_bug("no encrypt() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static int +dummy_decrypt( int algo, MPI *result, MPI *data, MPI *skey ) +{ log_bug("no decrypt() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static int +dummy_sign( int algo, MPI *resarr, MPI data, MPI *skey ) +{ log_bug("no sign() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static int +dummy_verify( int algo, MPI hash, MPI *data, MPI *pkey, + int (*cmp)(void *, MPI), void *opaquev ) +{ log_bug("no verify() for %d\n", algo ); return G10ERR_PUBKEY_ALGO; } + +static unsigned +dummy_get_nbits( int algo, MPI *pkey ) +{ log_bug("no get_nbits() for %d\n", algo ); return 0; } + + +/**************** + * Put the static entries into the table. + * This is out constructor function which fill the table + * of algorithms with the one we have statically linked. + */ +static void +setup_pubkey_table(void) +{ + int i; + + i = 0; + pubkey_table[i].algo = PUBKEY_ALGO_ELGAMAL; + pubkey_table[i].name = elg_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = elg_generate; + pubkey_table[i].check_secret_key = elg_check_secret_key; + pubkey_table[i].encrypt = elg_encrypt; + pubkey_table[i].decrypt = elg_decrypt; + pubkey_table[i].sign = elg_sign; + pubkey_table[i].verify = elg_verify; + pubkey_table[i].get_nbits = elg_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + pubkey_table[i].algo = PUBKEY_ALGO_ELGAMAL_E; + pubkey_table[i].name = elg_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = elg_generate; + pubkey_table[i].check_secret_key = elg_check_secret_key; + pubkey_table[i].encrypt = elg_encrypt; + pubkey_table[i].decrypt = elg_decrypt; + pubkey_table[i].sign = elg_sign; + pubkey_table[i].verify = elg_verify; + pubkey_table[i].get_nbits = elg_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + pubkey_table[i].algo = PUBKEY_ALGO_DSA; + pubkey_table[i].name = dsa_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = dsa_generate; + pubkey_table[i].check_secret_key = dsa_check_secret_key; + pubkey_table[i].encrypt = dummy_encrypt; + pubkey_table[i].decrypt = dummy_decrypt; + pubkey_table[i].sign = dsa_sign; + pubkey_table[i].verify = dsa_verify; + pubkey_table[i].get_nbits = dsa_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + + pubkey_table[i].algo = PUBKEY_ALGO_RSA; + pubkey_table[i].name = rsa_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = rsa_generate; + pubkey_table[i].check_secret_key = rsa_check_secret_key; + pubkey_table[i].encrypt = rsa_encrypt; + pubkey_table[i].decrypt = rsa_decrypt; + pubkey_table[i].sign = rsa_sign; + pubkey_table[i].verify = rsa_verify; + pubkey_table[i].get_nbits = rsa_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + pubkey_table[i].algo = PUBKEY_ALGO_RSA_E; + pubkey_table[i].name = rsa_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = rsa_generate; + pubkey_table[i].check_secret_key = rsa_check_secret_key; + pubkey_table[i].encrypt = rsa_encrypt; + pubkey_table[i].decrypt = rsa_decrypt; + pubkey_table[i].sign = dummy_sign; + pubkey_table[i].verify = dummy_verify; + pubkey_table[i].get_nbits = rsa_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + pubkey_table[i].algo = PUBKEY_ALGO_RSA_S; + pubkey_table[i].name = rsa_get_info( pubkey_table[i].algo, + &pubkey_table[i].npkey, + &pubkey_table[i].nskey, + &pubkey_table[i].nenc, + &pubkey_table[i].nsig, + &pubkey_table[i].use ); + pubkey_table[i].generate = rsa_generate; + pubkey_table[i].check_secret_key = rsa_check_secret_key; + pubkey_table[i].encrypt = dummy_encrypt; + pubkey_table[i].decrypt = dummy_decrypt; + pubkey_table[i].sign = rsa_sign; + pubkey_table[i].verify = rsa_verify; + pubkey_table[i].get_nbits = rsa_get_nbits; + if( !pubkey_table[i].name ) + BUG(); + i++; + + for( ; i < TABLE_SIZE; i++ ) + pubkey_table[i].name = NULL; +} + + +/**************** + * Try to load all modules and return true if new modules are available + */ +static int +load_pubkey_modules(void) +{ + static int initialized = 0; + static int done = 0; + void *context = NULL; + struct pubkey_table_s *ct; + int ct_idx; + int i; + const char *name; + int any = 0; + + + if( !initialized ) { + cipher_modules_constructor(); + setup_pubkey_table(); + initialized = 1; + return 1; + } + if( done ) + return 0; + done = 1; + for(ct_idx=0, ct = pubkey_table; ct_idx < TABLE_SIZE; ct_idx++,ct++ ) { + if( !ct->name ) + break; + } + if( ct_idx >= TABLE_SIZE-1 ) + BUG(); /* table already full */ + /* now load all extensions */ + while( (name = enum_gnupgext_pubkeys( &context, &ct->algo, + &ct->npkey, &ct->nskey, &ct->nenc, + &ct->nsig, &ct->use, + &ct->generate, + &ct->check_secret_key, + &ct->encrypt, + &ct->decrypt, + &ct->sign, + &ct->verify, + &ct->get_nbits )) ) { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == ct->algo ) + break; + if( pubkey_table[i].name ) { + log_info("skipping pubkey %d: already loaded\n", ct->algo ); + continue; + } + + if( !ct->generate ) ct->generate = dummy_generate; + if( !ct->check_secret_key ) ct->check_secret_key = + dummy_check_secret_key; + if( !ct->encrypt ) ct->encrypt = dummy_encrypt; + if( !ct->decrypt ) ct->decrypt = dummy_decrypt; + if( !ct->sign ) ct->sign = dummy_sign; + if( !ct->verify ) ct->verify = dummy_verify; + if( !ct->get_nbits ) ct->get_nbits= dummy_get_nbits; + /* put it into the table */ + if( g10_opt_verbose > 1 ) + log_info("loaded pubkey %d (%s)\n", ct->algo, name); + ct->name = name; + ct_idx++; + ct++; + any = 1; + /* check whether there are more available table slots */ + if( ct_idx >= TABLE_SIZE-1 ) { + log_info("pubkey table full; ignoring other extensions\n"); + break; + } + } + enum_gnupgext_pubkeys( &context, NULL, NULL, NULL, NULL, NULL, NULL, + NULL, NULL, NULL, NULL, NULL, NULL, NULL ); + return any; +} + + +/**************** + * Map a string to the pubkey algo + */ +int +string_to_pubkey_algo( const char *string ) +{ + int i; + const char *s; + + do { + for(i=0; (s=pubkey_table[i].name); i++ ) + if( !ascii_strcasecmp( s, string ) ) + return pubkey_table[i].algo; + } while( load_pubkey_modules() ); + return 0; +} + + +/**************** + * Map a pubkey algo to a string + */ +const char * +pubkey_algo_to_string( int algo ) +{ + int i; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return pubkey_table[i].name; + } while( load_pubkey_modules() ); + return NULL; +} + + +void +disable_pubkey_algo( int algo ) +{ + int i; + + for(i=0; i < DIM(disabled_algos); i++ ) { + if( !disabled_algos[i] || disabled_algos[i] == algo ) { + disabled_algos[i] = algo; + return; + } + } + log_fatal("can't disable pubkey algo %d: table full\n", algo ); +} + + +int +check_pubkey_algo( int algo ) +{ + return check_pubkey_algo2( algo, 0 ); +} + +/**************** + * a use of 0 means: don't care + */ +int +check_pubkey_algo2( int algo, unsigned use ) +{ + int i; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) { + if( (use & PUBKEY_USAGE_SIG) + && !(pubkey_table[i].use & PUBKEY_USAGE_SIG) ) + return G10ERR_WR_PUBKEY_ALGO; + if( (use & PUBKEY_USAGE_ENC) + && !(pubkey_table[i].use & PUBKEY_USAGE_ENC) ) + return G10ERR_WR_PUBKEY_ALGO; + + for(i=0; i < DIM(disabled_algos); i++ ) { + if( disabled_algos[i] == algo ) + return G10ERR_PUBKEY_ALGO; + } + return 0; /* okay */ + } + } while( load_pubkey_modules() ); + return G10ERR_PUBKEY_ALGO; +} + + + + +/**************** + * Return the number of public key material numbers + */ +int +pubkey_get_npkey( int algo ) +{ + int i; + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return pubkey_table[i].npkey; + } while( load_pubkey_modules() ); + return 0; +} + +/**************** + * Return the number of secret key material numbers + */ +int +pubkey_get_nskey( int algo ) +{ + int i; + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return pubkey_table[i].nskey; + } while( load_pubkey_modules() ); + if( is_RSA(algo) ) /* special hack, so that we are able to */ + return 6; /* see the RSA keyids */ + return 0; +} + +/**************** + * Return the number of signature material numbers + */ +int +pubkey_get_nsig( int algo ) +{ + int i; + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return pubkey_table[i].nsig; + } while( load_pubkey_modules() ); + if( is_RSA(algo) ) /* special hack, so that we are able to */ + return 1; /* see the RSA keyids */ + return 0; +} + +/**************** + * Return the number of encryption material numbers + */ +int +pubkey_get_nenc( int algo ) +{ + int i; + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return pubkey_table[i].nenc; + } while( load_pubkey_modules() ); + if( is_RSA(algo) ) /* special hack, so that we are able to */ + return 1; /* see the RSA keyids */ + return 0; +} + +/**************** + * Get the number of nbits from the public key + */ +unsigned +pubkey_nbits( int algo, MPI *pkey ) +{ + int i; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return (*pubkey_table[i].get_nbits)( algo, pkey ); + } while( load_pubkey_modules() ); + if( is_RSA(algo) ) /* we always wanna see the length of a key :-) */ + return mpi_get_nbits( pkey[0] ); + return 0; +} + + +int +pubkey_generate( int algo, unsigned nbits, MPI *skey, MPI **retfactors ) +{ + int i; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return (*pubkey_table[i].generate)( algo, nbits, + skey, retfactors ); + } while( load_pubkey_modules() ); + return G10ERR_PUBKEY_ALGO; +} + + +int +pubkey_check_secret_key( int algo, MPI *skey ) +{ + int i; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) + return (*pubkey_table[i].check_secret_key)( algo, skey ); + } while( load_pubkey_modules() ); + return G10ERR_PUBKEY_ALGO; +} + + +/**************** + * This is the interface to the public key encryption. + * Encrypt DATA with PKEY and put it into RESARR which + * should be an array of MPIs of size PUBKEY_MAX_NENC (or less if the + * algorithm allows this - check with pubkey_get_nenc() ) + */ +int +pubkey_encrypt( int algo, MPI *resarr, MPI data, MPI *pkey ) +{ + int i, rc; + + if( DBG_CIPHER ) { + log_debug("pubkey_encrypt: algo=%d\n", algo ); + for(i=0; i < pubkey_get_npkey(algo); i++ ) + log_mpidump(" pkey:", pkey[i] ); + log_mpidump(" data:", data ); + } + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) { + rc = (*pubkey_table[i].encrypt)( algo, resarr, data, pkey ); + goto ready; + } + } while( load_pubkey_modules() ); + rc = G10ERR_PUBKEY_ALGO; + ready: + if( !rc && DBG_CIPHER ) { + for(i=0; i < pubkey_get_nenc(algo); i++ ) + log_mpidump(" encr:", resarr[i] ); + } + return rc; +} + + + +/**************** + * This is the interface to the public key decryption. + * ALGO gives the algorithm to use and this implicitly determines + * the size of the arrays. + * result is a pointer to a mpi variable which will receive a + * newly allocated mpi or NULL in case of an error. + */ +int +pubkey_decrypt( int algo, MPI *result, MPI *data, MPI *skey ) +{ + int i, rc; + + *result = NULL; /* so the caller can always do an mpi_free */ + if( DBG_CIPHER ) { + log_debug("pubkey_decrypt: algo=%d\n", algo ); + for(i=0; i < pubkey_get_nskey(algo); i++ ) + log_mpidump(" skey:", skey[i] ); + for(i=0; i < pubkey_get_nenc(algo); i++ ) + log_mpidump(" data:", data[i] ); + } + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) { + rc = (*pubkey_table[i].decrypt)( algo, result, data, skey ); + goto ready; + } + } while( load_pubkey_modules() ); + rc = G10ERR_PUBKEY_ALGO; + ready: + if( !rc && DBG_CIPHER ) { + log_mpidump(" plain:", *result ); + } + return rc; +} + + +/**************** + * This is the interface to the public key signing. + * Sign data with skey and put the result into resarr which + * should be an array of MPIs of size PUBKEY_MAX_NSIG (or less if the + * algorithm allows this - check with pubkey_get_nsig() ) + */ +int +pubkey_sign( int algo, MPI *resarr, MPI data, MPI *skey ) +{ + int i, rc; + + if( DBG_CIPHER ) { + log_debug("pubkey_sign: algo=%d\n", algo ); + for(i=0; i < pubkey_get_nskey(algo); i++ ) + log_mpidump(" skey:", skey[i] ); + log_mpidump(" data:", data ); + } + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) { + rc = (*pubkey_table[i].sign)( algo, resarr, data, skey ); + goto ready; + } + } while( load_pubkey_modules() ); + rc = G10ERR_PUBKEY_ALGO; + ready: + if( !rc && DBG_CIPHER ) { + for(i=0; i < pubkey_get_nsig(algo); i++ ) + log_mpidump(" sig:", resarr[i] ); + } + return rc; +} + +/**************** + * Verify a public key signature. + * Return 0 if the signature is good + */ +int +pubkey_verify( int algo, MPI hash, MPI *data, MPI *pkey, + int (*cmp)(void *, MPI), void *opaquev ) +{ + int i, rc; + + do { + for(i=0; pubkey_table[i].name; i++ ) + if( pubkey_table[i].algo == algo ) { + rc = (*pubkey_table[i].verify)( algo, hash, data, pkey, + cmp, opaquev ); + goto ready; + } + } while( load_pubkey_modules() ); + rc = G10ERR_PUBKEY_ALGO; + ready: + return rc; +} + |