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author | Kibum Kim <kb0929.kim@samsung.com> | 2012-01-07 00:46:38 +0900 |
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committer | Kibum Kim <kb0929.kim@samsung.com> | 2012-01-07 00:46:38 +0900 |
commit | f5660c6460a863b19f9ef745575780e37cc192a9 (patch) | |
tree | 0b478679da32d706de7b0de546d2e4daf03b160c /g10/seckey-cert.c | |
parent | 06b9124a4f9d38acc78e6af686bc49a06f6354f8 (diff) | |
download | gnupg-f5660c6460a863b19f9ef745575780e37cc192a9.tar.gz gnupg-f5660c6460a863b19f9ef745575780e37cc192a9.tar.bz2 gnupg-f5660c6460a863b19f9ef745575780e37cc192a9.zip |
Diffstat (limited to 'g10/seckey-cert.c')
-rw-r--r-- | g10/seckey-cert.c | 427 |
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; +} + |