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Diffstat (limited to 'g10/seckey-cert.c')
| -rw-r--r-- | g10/seckey-cert.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/g10/seckey-cert.c b/g10/seckey-cert.c new file mode 100644 index 000000000..3cae571ab --- /dev/null +++ b/g10/seckey-cert.c @@ -0,0 +1,157 @@ +/* seckey-cert.c - secret key certifucate packet handling + * 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 <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" + + +static u16 +checksum( byte *p ) +{ + u16 n, a; + + n = *p++ << 8; + n |= *p++; + for(a=0; n; n-- ) + a += *p++; + return a; +} + + +/**************** + * Check the secret key certificate + */ +int +check_secret_key( PKT_seckey_cert *cert ) +{ + IDEA_context idea_ctx; /* FIXME: allocate this in secure space ! */ + byte iv[8]; + byte *mpibuf; + u16 n; + MPI temp_mpi; + int res; + u32 keyid[2]; + +#if IDEA_BLOCKSIZE != 8 || BLOWFISH_BLOCKSIZE != 8 + #error unsupportted blocksize +#endif + + if( cert->pubkey_algo != PUBKEY_ALGO_RSA ) + return G10ERR_PUBKEY_ALGO; /* unsupport algorithm */ + + if( cert->d.rsa.is_protected ) { /* remove the protection */ + DEK *dek = NULL; + BLOWFISH_context *blowfish_ctx=NULL; + + switch( cert->d.rsa.protect_algo ) { + case CIPHER_ALGO_NONE: + log_bug("unprotect seckey_cert is flagged protected\n"); + break; + case CIPHER_ALGO_IDEA: + case CIPHER_ALGO_BLOWFISH: + mpi_get_keyid( cert->d.rsa.rsa_n , keyid ); + dek = get_passphrase_hash( keyid, NULL ); + + /* idea_setkey( &idea_ctx, dpw );*/ + m_free(dek); /* pw is in secure memory, so m_free() burns it */ + memset( iv, 0, BLOWFISH_BLOCKSIZE ); + if( cert->d.rsa.protect_algo == CIPHER_ALGO_IDEA ) { + idea_setiv( &idea_ctx, iv ); + /* fixme: is it save to leave the IV unencrypted in the + * certificate or should we move it to secure storage? */ + idea_decode_cfb( &idea_ctx, cert->d.rsa.protect.idea.iv, + cert->d.rsa.protect.idea.iv, 8 ); + } + else { + blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx ); + blowfish_setiv( blowfish_ctx, iv ); + blowfish_decode_cfb( blowfish_ctx, + cert->d.rsa.protect.blowfish.iv, + cert->d.rsa.protect.blowfish.iv, 8 ); + } + cert->d.rsa.calc_csum = 0; + #define X(a) do { \ + mpibuf = (byte*)cert->d.rsa.rsa_##a; \ + n = ((mpibuf[0] << 8) | mpibuf[1])-2; \ + if( blowfish_ctx ) \ + blowfish_decode_cfb( blowfish_ctx, \ + mpibuf+4, mpibuf+4, n ); \ + else \ + idea_decode_cfb( &idea_ctx, mpibuf+4, mpibuf+4, n );\ + cert->d.rsa.calc_csum += checksum( mpibuf ); \ + cert->d.rsa.rsa_##a = mpi_decode_buffer( mpibuf ); \ + m_free( mpibuf ); \ + } while(0) + X(d); + X(p); + X(q); + X(u); + #undef X + m_free( blowfish_ctx ); + cert->d.rsa.is_protected = 0; + #if 0 + #define X(a) do { printf("\tRSA " #a ": "); \ + mpi_print(stdout, cert->d.rsa.rsa_##a, 1 ); \ + putchar('\n'); \ + } while(0) + X(n); + X(e); + X(d); + X(p); + X(q); + X(u); + #undef X + #endif + /* now let's see wether we have used the right passphrase */ + if( cert->d.rsa.calc_csum != cert->d.rsa.csum ) + return G10ERR_BAD_PASS; + temp_mpi = mpi_alloc(40); + mpi_mul(temp_mpi, cert->d.rsa.rsa_p, cert->d.rsa.rsa_q ); + res = mpi_cmp( temp_mpi, cert->d.rsa.rsa_n ); + mpi_free(temp_mpi); + if( res ) + return G10ERR_BAD_PASS; + break; + + default: + return G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */ + } + } + /* must check the checksum here, because we didn't do it when + * parsing an unprotected certificate */ + if( cert->d.rsa.calc_csum != cert->d.rsa.csum ) { + log_error("checksum in secret key certificate is wrong\n"); + log_debug("stored csum=%04hx calculated csum=%04hx\n", + cert->d.rsa.csum, cert->d.rsa.calc_csum ); + return G10ERR_CHECKSUM; + } + return 0; +} + + |