diff options
Diffstat (limited to 'libssh/src/bignum.c')
-rw-r--r-- | libssh/src/bignum.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/libssh/src/bignum.c b/libssh/src/bignum.c new file mode 100644 index 00000000..14b5aa54 --- /dev/null +++ b/libssh/src/bignum.c @@ -0,0 +1,96 @@ +/* + * This file is part of the SSH Library + * + * Copyright (c) 2014 by Aris Adamantiadis <aris@badcode.be> + * + * The SSH Library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The SSH Library 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 Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the SSH Library; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#include <stdio.h> + +#include "libssh/priv.h" +#include "libssh/bignum.h" +#include "libssh/string.h" + +ssh_string make_bignum_string(bignum num) { + ssh_string ptr = NULL; + int pad = 0; + unsigned int len = bignum_num_bytes(num); + unsigned int bits = bignum_num_bits(num); + + if (len == 0) { + return NULL; + } + + /* If the first bit is set we have a negative number */ + if (!(bits % 8) && bignum_is_bit_set(num, bits - 1)) { + pad++; + } + +#ifdef DEBUG_CRYPTO + fprintf(stderr, "%d bits, %d bytes, %d padding\n", bits, len, pad); +#endif /* DEBUG_CRYPTO */ + + ptr = ssh_string_new(len + pad); + if (ptr == NULL) { + return NULL; + } + + /* We have a negative number so we need a leading zero */ + if (pad) { + ptr->data[0] = 0; + } + +#ifdef HAVE_LIBGCRYPT + bignum_bn2bin(num, len, ptr->data + pad); +#elif HAVE_LIBCRYPTO + bignum_bn2bin(num, ptr->data + pad); +#endif + + return ptr; +} + +bignum make_string_bn(ssh_string string){ + bignum bn = NULL; + unsigned int len = ssh_string_len(string); + +#ifdef DEBUG_CRYPTO + fprintf(stderr, "Importing a %d bits, %d bytes object ...\n", + len * 8, len); +#endif /* DEBUG_CRYPTO */ + +#ifdef HAVE_LIBGCRYPT + bignum_bin2bn(string->data, len, &bn); +#elif defined HAVE_LIBCRYPTO + bn = bignum_bin2bn(string->data, len, NULL); +#endif + + return bn; +} + +/* prints the bignum on stderr */ +void ssh_print_bignum(const char *which, bignum num) { +#ifdef HAVE_LIBGCRYPT + unsigned char *hex = NULL; + bignum_bn2hex(num, &hex); +#elif defined HAVE_LIBCRYPTO + char *hex = NULL; + hex = bignum_bn2hex(num); +#endif + fprintf(stderr, "%s value: ", which); + fprintf(stderr, "%s\n", (hex == NULL) ? "(null)" : (char *) hex); + SAFE_FREE(hex); +} |