key.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * read_bignum():
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *
  * As far as I am concerned, the code I have written for this software
  * can be used freely for any purpose.  Any derived versions of this
  * software must be clearly marked as such, and if the derived work is
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  *
  *
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "includes.h"
 RCSID("$OpenBSD: key.c,v 1.17 2001/02/04 15:32:24 stevesk Exp $");

 #include <openssl/evp.h>

 #include "xmalloc.h"
 #include "key.h"
 #include "rsa.h"
 #include "ssh-dss.h"
 #include "ssh-rsa.h"
 #include "uuencode.h"
 #include "buffer.h"
 #include "bufaux.h"
 #include "log.h"

 Key *
 key_new(int type)
 {
 	Key *k;
 	RSA *rsa;
 	DSA *dsa;
 	k = xmalloc(sizeof(*k));
 	k->type = type;
 	k->dsa = NULL;
 	k->rsa = NULL;
 	switch (k->type) {
 	case KEY_RSA1:
 	case KEY_RSA:
 		rsa = RSA_new();
 		rsa->n = BN_new();
 		rsa->e = BN_new();
 		k->rsa = rsa;
 		break;
 	case KEY_DSA:
 		dsa = DSA_new();
 		dsa->p = BN_new();
 		dsa->q = BN_new();
 		dsa->g = BN_new();
 		dsa->pub_key = BN_new();
 		k->dsa = dsa;
 		break;
 	case KEY_UNSPEC:
 		break;
 	default:
 		fatal("key_new: bad key type %d", k->type);
 		break;
 	}
 	return k;
 }
 Key *
 key_new_private(int type)
 {
 	Key *k = key_new(type);
 	switch (k->type) {
 	case KEY_RSA1:
 	case KEY_RSA:
 		k->rsa->d = BN_new();
 		k->rsa->iqmp = BN_new();
 		k->rsa->q = BN_new();
 		k->rsa->p = BN_new();
 		k->rsa->dmq1 = BN_new();
 		k->rsa->dmp1 = BN_new();
 		break;
 	case KEY_DSA:
 		k->dsa->priv_key = BN_new();
 		break;
 	case KEY_UNSPEC:
 		break;
 	default:
 		break;
 	}
 	return k;
 }
 void
 key_free(Key *k)
 {
 	switch (k->type) {
 	case KEY_RSA1:
 	case KEY_RSA:
 		if (k->rsa != NULL)
 			RSA_free(k->rsa);
 		k->rsa = NULL;
 		break;
 	case KEY_DSA:
 		if (k->dsa != NULL)
 			DSA_free(k->dsa);
 		k->dsa = NULL;
 		break;
 	case KEY_UNSPEC:
 		break;
 	default:
 		fatal("key_free: bad key type %d", k->type);
 		break;
 	}
 	xfree(k);
 }
 int
 key_equal(Key *a, Key *b)
 {
 	if (a == NULL || b == NULL || a->type != b->type)
 		return 0;
 	switch (a->type) {
 	case KEY_RSA1:
 	case KEY_RSA:
 		return a->rsa != NULL && b->rsa != NULL &&
 		    BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
 		    BN_cmp(a->rsa->n, b->rsa->n) == 0;
 		break;
 	case KEY_DSA:
 		return a->dsa != NULL && b->dsa != NULL &&
 		    BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
 		    BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
 		    BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
 		    BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
 		break;
 	default:
 		fatal("key_equal: bad key type %d", a->type);
 		break;
 	}
 	return 0;
 }

 /*
  * Generate key fingerprint in ascii format.
  * Based on ideas and code from Bjoern Groenvall <bg@sics.se>
  */
 char *
 key_fingerprint(Key *k)
 {
 	static char retval[(EVP_MAX_MD_SIZE+1)*3];
 	u_char *blob = NULL;
 	int len = 0;
 	int nlen, elen;

 	retval[0] = '\0';
 	switch (k->type) {
 	case KEY_RSA1:
 		nlen = BN_num_bytes(k->rsa->n);
 		elen = BN_num_bytes(k->rsa->e);
 		len = nlen + elen;
 		blob = xmalloc(len);
 		BN_bn2bin(k->rsa->n, blob);
 		BN_bn2bin(k->rsa->e, blob + nlen);
 		break;
 	case KEY_DSA:
 	case KEY_RSA:
 		key_to_blob(k, &blob, &len);
 		break;
 	case KEY_UNSPEC:
 		return retval;
 		break;
 	default:
 		fatal("key_fingerprint: bad key type %d", k->type);
 		break;
 	}
 	if (blob != NULL) {
 		int i;
 		u_char digest[EVP_MAX_MD_SIZE];
 		EVP_MD *md = EVP_md5();
 		EVP_MD_CTX ctx;
 		EVP_DigestInit(&ctx, md);
 		EVP_DigestUpdate(&ctx, blob, len);
 		EVP_DigestFinal(&ctx, digest, NULL);
 		for(i = 0; i < md->md_size; i++) {
 			char hex[4];
 			snprintf(hex, sizeof(hex), "%02x:", digest[i]);
 			strlcat(retval, hex, sizeof(retval));
 		}
 		retval[strlen(retval) - 1] = '\0';
 		memset(blob, 0, len);
 		xfree(blob);
 	}
 	return retval;
 }

 /*
  * Reads a multiple-precision integer in decimal from the buffer, and advances
  * the pointer.  The integer must already be initialized.  This function is
  * permitted to modify the buffer.  This leaves *cpp to point just beyond the
  * last processed (and maybe modified) character.  Note that this may modify
  * the buffer containing the number.
  */
 int
 read_bignum(char **cpp, BIGNUM * value)
 {
 	char *cp = *cpp;
 	int old;

 	/* Skip any leading whitespace. */
 	for (; *cp == ' ' || *cp == '\t'; cp++)
 		;

 	/* Check that it begins with a decimal digit. */
 	if (*cp < '0' || *cp > '9')
 		return 0;

 	/* Save starting position. */
 	*cpp = cp;

 	/* Move forward until all decimal digits skipped. */
 	for (; *cp >= '0' && *cp <= '9'; cp++)
 		;

 	/* Save the old terminating character, and replace it by \0. */
 	old = *cp;
 	*cp = 0;

 	/* Parse the number. */
 	if (BN_dec2bn(&value, *cpp) == 0)
 		return 0;

 	/* Restore old terminating character. */
 	*cp = old;

 	/* Move beyond the number and return success. */
 	*cpp = cp;
 	return 1;
 }
 int
 write_bignum(FILE *f, BIGNUM *num)
 {
 	char *buf = BN_bn2dec(num);
 	if (buf == NULL) {
 		error("write_bignum: BN_bn2dec() failed");
 		return 0;
 	}
 	fprintf(f, " %s", buf);
 	xfree(buf);
 	return 1;
 }

 /* returns 1 ok, -1 error, 0 type mismatch */
 int
 key_read(Key *ret, char **cpp)
 {
 	Key *k;
 	int success = -1;
 	char *cp, *space;
 	int len, n, type;
 	u_int bits;
 	u_char *blob;

 	cp = *cpp;

 	switch(ret->type) {
 	case KEY_RSA1:
 		/* Get number of bits. */
 		if (*cp < '0' || *cp > '9')
 			return -1;	/* Bad bit count... */
 		for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
 			bits = 10 * bits + *cp - '0';
 		if (bits == 0)
 			return -1;
 		*cpp = cp;
 		/* Get public exponent, public modulus. */
 		if (!read_bignum(cpp, ret->rsa->e))
 			return -1;
 		if (!read_bignum(cpp, ret->rsa->n))
 			return -1;
 		success = 1;
 		break;
 	case KEY_UNSPEC:
 	case KEY_RSA:
 	case KEY_DSA:
 		space = strchr(cp, ' ');
 		if (space == NULL) {
 			debug3("key_read: no space");
 			return -1;
 		}
 		*space = '\0';
 		type = key_type_from_name(cp);
 		*space = ' ';
 		if (type == KEY_UNSPEC) {
 			debug3("key_read: no key found");
 			return -1;
 		}
 		cp = space+1;
 		if (*cp == '\0') {
 			debug3("key_read: short string");
 			return -1;
 		}
 		if (ret->type == KEY_UNSPEC) {
 			ret->type = type;
 		} else if (ret->type != type) {
 			/* is a key, but different type */
 			debug3("key_read: type mismatch");
 			return 0;
 		}
 		len = 2*strlen(cp);
 		blob = xmalloc(len);
 		n = uudecode(cp, blob, len);
 		if (n < 0) {
 			error("key_read: uudecode %s failed", cp);
 			return -1;
 		}
 		k = key_from_blob(blob, n);
 		if (k == NULL) {
 			error("key_read: key_from_blob %s failed", cp);
 			return -1;
 		}
 		xfree(blob);
 		if (k->type != type) {
 			error("key_read: type mismatch: encoding error");
 			key_free(k);
 			return -1;
 		}
 /*XXXX*/
 		if (ret->type == KEY_RSA) {
 			if (ret->rsa != NULL)
 				RSA_free(ret->rsa);
 			ret->rsa = k->rsa;
 			k->rsa = NULL;
 			success = 1;
 #ifdef DEBUG_PK
 			RSA_print_fp(stderr, ret->rsa, 8);
 #endif
 		} else {
 			if (ret->dsa != NULL)
 				DSA_free(ret->dsa);
 			ret->dsa = k->dsa;
 			k->dsa = NULL;
 			success = 1;
 #ifdef DEBUG_PK
 			DSA_print_fp(stderr, ret->dsa, 8);
 #endif
 		}
 /*XXXX*/
 		if (success != 1)
 			break;
 		key_free(k);
 		/* advance cp: skip whitespace and data */
 		while (*cp == ' ' || *cp == '\t')
 			cp++;
 		while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 			cp++;
 		*cpp = cp;
 		break;
 	default:
 		fatal("key_read: bad key type: %d", ret->type);
 		break;
 	}
 	return success;
 }
 int
 key_write(Key *key, FILE *f)
 {
 	int success = 0;
 	u_int bits = 0;

 	if (key->type == KEY_RSA1 && key->rsa != NULL) {
 		/* size of modulus 'n' */
 		bits = BN_num_bits(key->rsa->n);
 		fprintf(f, "%u", bits);
 		if (write_bignum(f, key->rsa->e) &&
 		    write_bignum(f, key->rsa->n)) {
 			success = 1;
 		} else {
 			error("key_write: failed for RSA key");
 		}
 	} else if ((key->type == KEY_DSA && key->dsa != NULL) ||
 	    (key->type == KEY_RSA && key->rsa != NULL)) {
 		int len, n;
 		u_char *blob, *uu;
 		key_to_blob(key, &blob, &len);
 		uu = xmalloc(2*len);
 		n = uuencode(blob, len, uu, 2*len);
 		if (n > 0) {
 			fprintf(f, "%s %s", key_ssh_name(key), uu);
 			success = 1;
 		}
 		xfree(blob);
 		xfree(uu);
 	}
 	return success;
 }
 char *
 key_type(Key *k)
 {
 	switch (k->type) {
 	case KEY_RSA1:
 		return "RSA1";
 		break;
 	case KEY_RSA:
 		return "RSA";
 		break;
 	case KEY_DSA:
 		return "DSA";
 		break;
 	}
 	return "unknown";
 }
 char *
 key_ssh_name(Key *k)
 {
 	switch (k->type) {
 	case KEY_RSA:
 		return "ssh-rsa";
 		break;
 	case KEY_DSA:
 		return "ssh-dss";
 		break;
 	}
 	return "ssh-unknown";
 }
 u_int
 key_size(Key *k){
 	switch (k->type) {
 	case KEY_RSA1:
 	case KEY_RSA:
 		return BN_num_bits(k->rsa->n);
 		break;
 	case KEY_DSA:
 		return BN_num_bits(k->dsa->p);
 		break;
 	}
 	return 0;
 }

 RSA *
 rsa_generate_private_key(u_int bits)
 {
 	RSA *private;
 	private = RSA_generate_key(bits, 35, NULL, NULL);
 	if (private == NULL)
 		fatal("rsa_generate_private_key: key generation failed.");
 	return private;
 }

 DSA*
 dsa_generate_private_key(u_int bits)
 {
 	DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
 	if (private == NULL)
 		fatal("dsa_generate_private_key: DSA_generate_parameters failed");
 	if (!DSA_generate_key(private))
 		fatal("dsa_generate_private_key: DSA_generate_key failed.");
 	if (private == NULL)
 		fatal("dsa_generate_private_key: NULL.");
 	return private;
 }

 Key *
 key_generate(int type, u_int bits)
 {
 	Key *k = key_new(KEY_UNSPEC);
 	switch (type) {
 	case KEY_DSA:
 		k->dsa = dsa_generate_private_key(bits);
 		break;
 	case KEY_RSA:
 	case KEY_RSA1:
 		k->rsa = rsa_generate_private_key(bits);
 		break;
 	default:
 		fatal("key_generate: unknown type %d", type);
 	}
 	k->type = type;
 	return k;
 }

 Key *
 key_from_private(Key *k)
 {
 	Key *n = NULL;
 	switch (k->type) {
 	case KEY_DSA:
 		n = key_new(k->type);
 		BN_copy(n->dsa->p, k->dsa->p);
 		BN_copy(n->dsa->q, k->dsa->q);
 		BN_copy(n->dsa->g, k->dsa->g);
 		BN_copy(n->dsa->pub_key, k->dsa->pub_key);
 		break;
 	case KEY_RSA:
 	case KEY_RSA1:
 		n = key_new(k->type);
 		BN_copy(n->rsa->n, k->rsa->n);
 		BN_copy(n->rsa->e, k->rsa->e);
 		break;
 	default:
 		fatal("key_from_private: unknown type %d", k->type);
 		break;
 	}
 	return n;
 }

 int
 key_type_from_name(char *name)
 {
 	if (strcmp(name, "rsa1") == 0){
 		return KEY_RSA1;
 	} else if (strcmp(name, "rsa") == 0){
 		return KEY_RSA;
 	} else if (strcmp(name, "dsa") == 0){
 		return KEY_DSA;
 	} else if (strcmp(name, "ssh-rsa") == 0){
 		return KEY_RSA;
 	} else if (strcmp(name, "ssh-dss") == 0){
 		return KEY_DSA;
 	}
 	debug("key_type_from_name: unknown key type '%s'", name);
 	return KEY_UNSPEC;
 }

 Key *
 key_from_blob(char *blob, int blen)
 {
 	Buffer b;
 	char *ktype;
 	int rlen, type;
 	Key *key = NULL;

 #ifdef DEBUG_PK
 	dump_base64(stderr, blob, blen);
 #endif
 	buffer_init(&b);
 	buffer_append(&b, blob, blen);
 	ktype = buffer_get_string(&b, NULL);
 	type = key_type_from_name(ktype);

 	switch(type){
 	case KEY_RSA:
 		key = key_new(type);
 		buffer_get_bignum2(&b, key->rsa->e);
 		buffer_get_bignum2(&b, key->rsa->n);
 #ifdef DEBUG_PK
 		RSA_print_fp(stderr, key->rsa, 8);
 #endif
 		break;
 	case KEY_DSA:
 		key = key_new(type);
 		buffer_get_bignum2(&b, key->dsa->p);
 		buffer_get_bignum2(&b, key->dsa->q);
 		buffer_get_bignum2(&b, key->dsa->g);
 		buffer_get_bignum2(&b, key->dsa->pub_key);
 #ifdef DEBUG_PK
 		DSA_print_fp(stderr, key->dsa, 8);
 #endif
 		break;
 	case KEY_UNSPEC:
 		key = key_new(type);
 		break;
 	default:
 		error("key_from_blob: cannot handle type %s", ktype);
 		break;
 	}
 	rlen = buffer_len(&b);
 	if (key != NULL && rlen != 0)
 		error("key_from_blob: remaining bytes in key blob %d", rlen);
 	xfree(ktype);
 	buffer_free(&b);
 	return key;
 }

 int
 key_to_blob(Key *key, u_char **blobp, u_int *lenp)
 {
 	Buffer b;
 	int len;
 	u_char *buf;

 	if (key == NULL) {
 		error("key_to_blob: key == NULL");
 		return 0;
 	}
 	buffer_init(&b);
 	switch(key->type){
 	case KEY_DSA:
 		buffer_put_cstring(&b, key_ssh_name(key));
 		buffer_put_bignum2(&b, key->dsa->p);
 		buffer_put_bignum2(&b, key->dsa->q);
 		buffer_put_bignum2(&b, key->dsa->g);
 		buffer_put_bignum2(&b, key->dsa->pub_key);
 		break;
 	case KEY_RSA:
 		buffer_put_cstring(&b, key_ssh_name(key));
 		buffer_put_bignum2(&b, key->rsa->e);
 		buffer_put_bignum2(&b, key->rsa->n);
 		break;
 	default:
 		error("key_to_blob: illegal key type %d", key->type);
 		break;
 	}
 	len = buffer_len(&b);
 	buf = xmalloc(len);
 	memcpy(buf, buffer_ptr(&b), len);
 	memset(buffer_ptr(&b), 0, len);
 	buffer_free(&b);
 	if (lenp != NULL)
 		*lenp = len;
 	if (blobp != NULL)
 		*blobp = buf;
 	return len;
 }

 int
 key_sign(
     Key *key,
     u_char **sigp, int *lenp,
     u_char *data, int datalen)
 {
 	switch(key->type){
 	case KEY_DSA:
 		return ssh_dss_sign(key, sigp, lenp, data, datalen);
 		break;
 	case KEY_RSA:
 		return ssh_rsa_sign(key, sigp, lenp, data, datalen);
 		break;
 	default:
 		error("key_sign: illegal key type %d", key->type);
 		return -1;
 		break;
 	}
 }

 int
 key_verify(
     Key *key,
     u_char *signature, int signaturelen,
     u_char *data, int datalen)
 {
 	switch(key->type){
 	case KEY_DSA:
 		return ssh_dss_verify(key, signature, signaturelen, data, datalen);
 		break;
 	case KEY_RSA:
 		return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
 		break;
 	default:
 		error("key_verify: illegal key type %d", key->type);
 		return -1;
 		break;
 	}
 }
	/*
	* read_bignum():
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	*
	* As far as I am concerned, the code I have written for this software
	* can be used freely for any purpose. Any derived versions of this
	* software must be clearly marked as such, and if the derived work is
	* incompatible with the protocol description in the RFC file, it must be
	* called by a name other than "ssh" or "Secure Shell".
	*
	*
	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	#include "includes.h"
	RCSID("$OpenBSD: key.c,v 1.17 2001/02/04 15:32:24 stevesk Exp $");

	#include <openssl/evp.h>

	#include "xmalloc.h"
	#include "key.h"
	#include "rsa.h"
	#include "ssh-dss.h"
	#include "ssh-rsa.h"
	#include "uuencode.h"
	#include "buffer.h"
	#include "bufaux.h"
	#include "log.h"

	Key *
	key_new(int type)
	{
	Key *k;
	RSA *rsa;
	DSA *dsa;
	k = xmalloc(sizeof(*k));
	k->type = type;
	k->dsa = NULL;
	k->rsa = NULL;
	switch (k->type) {
	case KEY_RSA1:
	case KEY_RSA:
	rsa = RSA_new();
	rsa->n = BN_new();
	rsa->e = BN_new();
	k->rsa = rsa;
	break;
	case KEY_DSA:
	dsa = DSA_new();
	dsa->p = BN_new();
	dsa->q = BN_new();
	dsa->g = BN_new();
	dsa->pub_key = BN_new();
	k->dsa = dsa;
	break;
	case KEY_UNSPEC:
	break;
	default:
	fatal("key_new: bad key type %d", k->type);
	break;
	}
	return k;
	}
	Key *
	key_new_private(int type)
	{
	Key *k = key_new(type);
	switch (k->type) {
	case KEY_RSA1:
	case KEY_RSA:
	k->rsa->d = BN_new();
	k->rsa->iqmp = BN_new();
	k->rsa->q = BN_new();
	k->rsa->p = BN_new();
	k->rsa->dmq1 = BN_new();
	k->rsa->dmp1 = BN_new();
	break;
	case KEY_DSA:
	k->dsa->priv_key = BN_new();
	break;
	case KEY_UNSPEC:
	break;
	default:
	break;
	}
	return k;
	}
	void
	key_free(Key *k)
	{
	switch (k->type) {
	case KEY_RSA1:
	case KEY_RSA:
	if (k->rsa != NULL)
	RSA_free(k->rsa);
	k->rsa = NULL;
	break;
	case KEY_DSA:
	if (k->dsa != NULL)
	DSA_free(k->dsa);
	k->dsa = NULL;
	break;
	case KEY_UNSPEC:
	break;
	default:
	fatal("key_free: bad key type %d", k->type);
	break;
	}
	xfree(k);
	}
	int
	key_equal(Key a, Key b)
	{
	if (a == NULL \|\| b == NULL \|\| a->type != b->type)
	return 0;
	switch (a->type) {
	case KEY_RSA1:
	case KEY_RSA:
	return a->rsa != NULL && b->rsa != NULL &&
	BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
	BN_cmp(a->rsa->n, b->rsa->n) == 0;
	break;
	case KEY_DSA:
	return a->dsa != NULL && b->dsa != NULL &&
	BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
	BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
	BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
	BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
	break;
	default:
	fatal("key_equal: bad key type %d", a->type);
	break;
	}
	return 0;
	}

	/*
	* Generate key fingerprint in ascii format.
	* Based on ideas and code from Bjoern Groenvall <bg@sics.se>
	*/
	char *
	key_fingerprint(Key *k)
	{
	static char retval[(EVP_MAX_MD_SIZE+1)*3];
	u_char *blob = NULL;
	int len = 0;
	int nlen, elen;

	retval[0] = '\0';
	switch (k->type) {
	case KEY_RSA1:
	nlen = BN_num_bytes(k->rsa->n);
	elen = BN_num_bytes(k->rsa->e);
	len = nlen + elen;
	blob = xmalloc(len);
	BN_bn2bin(k->rsa->n, blob);
	BN_bn2bin(k->rsa->e, blob + nlen);
	break;
	case KEY_DSA:
	case KEY_RSA:
	key_to_blob(k, &blob, &len);
	break;
	case KEY_UNSPEC:
	return retval;
	break;
	default:
	fatal("key_fingerprint: bad key type %d", k->type);
	break;
	}
	if (blob != NULL) {
	int i;
	u_char digest[EVP_MAX_MD_SIZE];
	EVP_MD *md = EVP_md5();
	EVP_MD_CTX ctx;
	EVP_DigestInit(&ctx, md);
	EVP_DigestUpdate(&ctx, blob, len);
	EVP_DigestFinal(&ctx, digest, NULL);
	for(i = 0; i < md->md_size; i++) {
	char hex[4];
	snprintf(hex, sizeof(hex), "%02x:", digest[i]);
	strlcat(retval, hex, sizeof(retval));
	}
	retval[strlen(retval) - 1] = '\0';
	memset(blob, 0, len);
	xfree(blob);
	}
	return retval;
	}

	/*
	* Reads a multiple-precision integer in decimal from the buffer, and advances
	* the pointer. The integer must already be initialized. This function is
	* permitted to modify the buffer. This leaves *cpp to point just beyond the
	* last processed (and maybe modified) character. Note that this may modify
	* the buffer containing the number.
	*/
	int
	read_bignum(char *cpp, BIGNUM value)
	{
	char cp = cpp;
	int old;

	/* Skip any leading whitespace. */
	for (; cp == ' ' \|\| cp == '\t'; cp++)
	;

	/* Check that it begins with a decimal digit. */
	if (cp < '0' \|\| cp > '9')
	return 0;

	/* Save starting position. */
	*cpp = cp;

	/* Move forward until all decimal digits skipped. */
	for (; cp >= '0' && cp <= '9'; cp++)
	;

	/* Save the old terminating character, and replace it by \0. */
	old = *cp;
	*cp = 0;

	/* Parse the number. */
	if (BN_dec2bn(&value, *cpp) == 0)
	return 0;

	/* Restore old terminating character. */
	*cp = old;

	/* Move beyond the number and return success. */
	*cpp = cp;
	return 1;
	}
	int
	write_bignum(FILE f, BIGNUM num)
	{
	char *buf = BN_bn2dec(num);
	if (buf == NULL) {
	error("write_bignum: BN_bn2dec() failed");
	return 0;
	}
	fprintf(f, " %s", buf);
	xfree(buf);
	return 1;
	}

	/* returns 1 ok, -1 error, 0 type mismatch */
	int
	key_read(Key ret, char *cpp)
	{
	Key *k;
	int success = -1;
	char cp, space;
	int len, n, type;
	u_int bits;
	u_char *blob;

	cp = *cpp;

	switch(ret->type) {
	case KEY_RSA1:
	/* Get number of bits. */
	if (cp < '0' \|\| cp > '9')
	return -1; /* Bad bit count... */
	for (bits = 0; cp >= '0' && cp <= '9'; cp++)
	bits = 10 * bits + *cp - '0';
	if (bits == 0)
	return -1;
	*cpp = cp;
	/* Get public exponent, public modulus. */
	if (!read_bignum(cpp, ret->rsa->e))
	return -1;
	if (!read_bignum(cpp, ret->rsa->n))
	return -1;
	success = 1;
	break;
	case KEY_UNSPEC:
	case KEY_RSA:
	case KEY_DSA:
	space = strchr(cp, ' ');
	if (space == NULL) {
	debug3("key_read: no space");
	return -1;
	}
	*space = '\0';
	type = key_type_from_name(cp);
	*space = ' ';
	if (type == KEY_UNSPEC) {
	debug3("key_read: no key found");
	return -1;
	}
	cp = space+1;
	if (*cp == '\0') {
	debug3("key_read: short string");
	return -1;
	}
	if (ret->type == KEY_UNSPEC) {
	ret->type = type;
	} else if (ret->type != type) {
	/* is a key, but different type */
	debug3("key_read: type mismatch");
	return 0;
	}
	len = 2*strlen(cp);
	blob = xmalloc(len);
	n = uudecode(cp, blob, len);
	if (n < 0) {
	error("key_read: uudecode %s failed", cp);
	return -1;
	}
	k = key_from_blob(blob, n);
	if (k == NULL) {
	error("key_read: key_from_blob %s failed", cp);
	return -1;
	}
	xfree(blob);
	if (k->type != type) {
	error("key_read: type mismatch: encoding error");
	key_free(k);
	return -1;
	}
	/XXXX/
	if (ret->type == KEY_RSA) {
	if (ret->rsa != NULL)
	RSA_free(ret->rsa);
	ret->rsa = k->rsa;
	k->rsa = NULL;
	success = 1;
	#ifdef DEBUG_PK
	RSA_print_fp(stderr, ret->rsa, 8);
	#endif
	} else {
	if (ret->dsa != NULL)
	DSA_free(ret->dsa);
	ret->dsa = k->dsa;
	k->dsa = NULL;
	success = 1;
	#ifdef DEBUG_PK
	DSA_print_fp(stderr, ret->dsa, 8);
	#endif
	}
	/XXXX/
	if (success != 1)
	break;
	key_free(k);
	/* advance cp: skip whitespace and data */
	while (cp == ' ' \|\| cp == '\t')
	cp++;
	while (cp != '\0' && cp != ' ' && *cp != '\t')
	cp++;
	*cpp = cp;
	break;
	default:
	fatal("key_read: bad key type: %d", ret->type);
	break;
	}
	return success;
	}
	int
	key_write(Key key, FILE f)
	{
	int success = 0;
	u_int bits = 0;

	if (key->type == KEY_RSA1 && key->rsa != NULL) {
	/* size of modulus 'n' */
	bits = BN_num_bits(key->rsa->n);
	fprintf(f, "%u", bits);
	if (write_bignum(f, key->rsa->e) &&
	write_bignum(f, key->rsa->n)) {
	success = 1;
	} else {
	error("key_write: failed for RSA key");
	}
	} else if ((key->type == KEY_DSA && key->dsa != NULL) \|\|
	(key->type == KEY_RSA && key->rsa != NULL)) {
	int len, n;
	u_char blob, uu;
	key_to_blob(key, &blob, &len);
	uu = xmalloc(2*len);
	n = uuencode(blob, len, uu, 2*len);
	if (n > 0) {
	fprintf(f, "%s %s", key_ssh_name(key), uu);
	success = 1;
	}
	xfree(blob);
	xfree(uu);
	}
	return success;
	}
	char *
	key_type(Key *k)
	{
	switch (k->type) {
	case KEY_RSA1:
	return "RSA1";
	break;
	case KEY_RSA:
	return "RSA";
	break;
	case KEY_DSA:
	return "DSA";
	break;
	}
	return "unknown";
	}
	char *
	key_ssh_name(Key *k)
	{
	switch (k->type) {
	case KEY_RSA:
	return "ssh-rsa";
	break;
	case KEY_DSA:
	return "ssh-dss";
	break;
	}
	return "ssh-unknown";
	}
	u_int
	key_size(Key *k){
	switch (k->type) {
	case KEY_RSA1:
	case KEY_RSA:
	return BN_num_bits(k->rsa->n);
	break;
	case KEY_DSA:
	return BN_num_bits(k->dsa->p);
	break;
	}
	return 0;
	}

	RSA *
	rsa_generate_private_key(u_int bits)
	{
	RSA *private;
	private = RSA_generate_key(bits, 35, NULL, NULL);
	if (private == NULL)
	fatal("rsa_generate_private_key: key generation failed.");
	return private;
	}

	DSA*
	dsa_generate_private_key(u_int bits)
	{
	DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
	if (private == NULL)
	fatal("dsa_generate_private_key: DSA_generate_parameters failed");
	if (!DSA_generate_key(private))
	fatal("dsa_generate_private_key: DSA_generate_key failed.");
	if (private == NULL)
	fatal("dsa_generate_private_key: NULL.");
	return private;
	}

	Key *
	key_generate(int type, u_int bits)
	{
	Key *k = key_new(KEY_UNSPEC);
	switch (type) {
	case KEY_DSA:
	k->dsa = dsa_generate_private_key(bits);
	break;
	case KEY_RSA:
	case KEY_RSA1:
	k->rsa = rsa_generate_private_key(bits);
	break;
	default:
	fatal("key_generate: unknown type %d", type);
	}
	k->type = type;
	return k;
	}

	Key *
	key_from_private(Key *k)
	{
	Key *n = NULL;
	switch (k->type) {
	case KEY_DSA:
	n = key_new(k->type);
	BN_copy(n->dsa->p, k->dsa->p);
	BN_copy(n->dsa->q, k->dsa->q);
	BN_copy(n->dsa->g, k->dsa->g);
	BN_copy(n->dsa->pub_key, k->dsa->pub_key);
	break;
	case KEY_RSA:
	case KEY_RSA1:
	n = key_new(k->type);
	BN_copy(n->rsa->n, k->rsa->n);
	BN_copy(n->rsa->e, k->rsa->e);
	break;
	default:
	fatal("key_from_private: unknown type %d", k->type);
	break;
	}
	return n;
	}

	int
	key_type_from_name(char *name)
	{
	if (strcmp(name, "rsa1") == 0){
	return KEY_RSA1;
	} else if (strcmp(name, "rsa") == 0){
	return KEY_RSA;
	} else if (strcmp(name, "dsa") == 0){
	return KEY_DSA;
	} else if (strcmp(name, "ssh-rsa") == 0){
	return KEY_RSA;
	} else if (strcmp(name, "ssh-dss") == 0){
	return KEY_DSA;
	}
	debug("key_type_from_name: unknown key type '%s'", name);
	return KEY_UNSPEC;
	}

	Key *
	key_from_blob(char *blob, int blen)
	{
	Buffer b;
	char *ktype;
	int rlen, type;
	Key *key = NULL;

	#ifdef DEBUG_PK
	dump_base64(stderr, blob, blen);
	#endif
	buffer_init(&b);
	buffer_append(&b, blob, blen);
	ktype = buffer_get_string(&b, NULL);
	type = key_type_from_name(ktype);

	switch(type){
	case KEY_RSA:
	key = key_new(type);
	buffer_get_bignum2(&b, key->rsa->e);
	buffer_get_bignum2(&b, key->rsa->n);
	#ifdef DEBUG_PK
	RSA_print_fp(stderr, key->rsa, 8);
	#endif
	break;
	case KEY_DSA:
	key = key_new(type);
	buffer_get_bignum2(&b, key->dsa->p);
	buffer_get_bignum2(&b, key->dsa->q);
	buffer_get_bignum2(&b, key->dsa->g);
	buffer_get_bignum2(&b, key->dsa->pub_key);
	#ifdef DEBUG_PK
	DSA_print_fp(stderr, key->dsa, 8);
	#endif
	break;
	case KEY_UNSPEC:
	key = key_new(type);
	break;
	default:
	error("key_from_blob: cannot handle type %s", ktype);
	break;
	}
	rlen = buffer_len(&b);
	if (key != NULL && rlen != 0)
	error("key_from_blob: remaining bytes in key blob %d", rlen);
	xfree(ktype);
	buffer_free(&b);
	return key;
	}

	int
	key_to_blob(Key key, u_char blobp, u_int lenp)
	{
	Buffer b;
	int len;
	u_char *buf;

	if (key == NULL) {
	error("key_to_blob: key == NULL");
	return 0;
	}
	buffer_init(&b);
	switch(key->type){
	case KEY_DSA:
	buffer_put_cstring(&b, key_ssh_name(key));
	buffer_put_bignum2(&b, key->dsa->p);
	buffer_put_bignum2(&b, key->dsa->q);
	buffer_put_bignum2(&b, key->dsa->g);
	buffer_put_bignum2(&b, key->dsa->pub_key);
	break;
	case KEY_RSA:
	buffer_put_cstring(&b, key_ssh_name(key));
	buffer_put_bignum2(&b, key->rsa->e);
	buffer_put_bignum2(&b, key->rsa->n);
	break;
	default:
	error("key_to_blob: illegal key type %d", key->type);
	break;
	}
	len = buffer_len(&b);
	buf = xmalloc(len);
	memcpy(buf, buffer_ptr(&b), len);
	memset(buffer_ptr(&b), 0, len);
	buffer_free(&b);
	if (lenp != NULL)
	*lenp = len;
	if (blobp != NULL)
	*blobp = buf;
	return len;
	}

	int
	key_sign(
	Key *key,
	u_char *sigp, int lenp,
	u_char *data, int datalen)
	{
	switch(key->type){
	case KEY_DSA:
	return ssh_dss_sign(key, sigp, lenp, data, datalen);
	break;
	case KEY_RSA:
	return ssh_rsa_sign(key, sigp, lenp, data, datalen);
	break;
	default:
	error("key_sign: illegal key type %d", key->type);
	return -1;
	break;
	}
	}

	int
	key_verify(
	Key *key,
	u_char *signature, int signaturelen,
	u_char *data, int datalen)
	{
	switch(key->type){
	case KEY_DSA:
	return ssh_dss_verify(key, signature, signaturelen, data, datalen);
	break;
	case KEY_RSA:
	return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
	break;
	default:
	error("key_verify: illegal key type %d", key->type);
	return -1;
	break;
	}
	}