[openssh.git] / authfile.c

/*
 *
 * authfile.c
 *
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 *
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * Created: Mon Mar 27 03:52:05 1995 ylo
 *
 * This file contains functions for reading and writing identity files, and
 * for reading the passphrase from the user.
 *
 */

#include "includes.h"
RCSID("$OpenBSD: authfile.c,v 1.17 2000/06/20 01:39:38 markus Exp $");

#include <openssl/bn.h>
#include <openssl/dsa.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>

#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"
#include "cipher.h"
#include "ssh.h"
#include "key.h"

/* Version identification string for identity files. */
#define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n"

/*
 * Saves the authentication (private) key in a file, encrypting it with
 * passphrase.  The identification of the file (lowest 64 bits of n) will
 * precede the key to provide identification of the key without needing a
 * passphrase.
 */

int
save_private_key_rsa(const char *filename, const char *passphrase,
    RSA *key, const char *comment)
{
	Buffer buffer, encrypted;
	char buf[100], *cp;
	int fd, i;
	CipherContext cipher;
	int cipher_type;
	u_int32_t rand;

	/*
	 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
	 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
	 */
	if (strcmp(passphrase, "") == 0)
		cipher_type = SSH_CIPHER_NONE;
	else
		cipher_type = SSH_AUTHFILE_CIPHER;

	/* This buffer is used to built the secret part of the private key. */
	buffer_init(&buffer);

	/* Put checkbytes for checking passphrase validity. */
	rand = arc4random();
	buf[0] = rand & 0xff;
	buf[1] = (rand >> 8) & 0xff;
	buf[2] = buf[0];
	buf[3] = buf[1];
	buffer_append(&buffer, buf, 4);

	/*
	 * Store the private key (n and e will not be stored because they
	 * will be stored in plain text, and storing them also in encrypted
	 * format would just give known plaintext).
	 */
	buffer_put_bignum(&buffer, key->d);
	buffer_put_bignum(&buffer, key->iqmp);
	buffer_put_bignum(&buffer, key->q);	/* reverse from SSL p */
	buffer_put_bignum(&buffer, key->p);	/* reverse from SSL q */

	/* Pad the part to be encrypted until its size is a multiple of 8. */
	while (buffer_len(&buffer) % 8 != 0)
		buffer_put_char(&buffer, 0);

	/* This buffer will be used to contain the data in the file. */
	buffer_init(&encrypted);

	/* First store keyfile id string. */
	cp = AUTHFILE_ID_STRING;
	for (i = 0; cp[i]; i++)
		buffer_put_char(&encrypted, cp[i]);
	buffer_put_char(&encrypted, 0);

	/* Store cipher type. */
	buffer_put_char(&encrypted, cipher_type);
	buffer_put_int(&encrypted, 0);	/* For future extension */

	/* Store public key.  This will be in plain text. */
	buffer_put_int(&encrypted, BN_num_bits(key->n));
	buffer_put_bignum(&encrypted, key->n);
	buffer_put_bignum(&encrypted, key->e);
	buffer_put_string(&encrypted, comment, strlen(comment));

	/* Allocate space for the private part of the key in the buffer. */
	buffer_append_space(&encrypted, &cp, buffer_len(&buffer));

	cipher_set_key_string(&cipher, cipher_type, passphrase);
	cipher_encrypt(&cipher, (unsigned char *) cp,
		       (unsigned char *) buffer_ptr(&buffer),
		       buffer_len(&buffer));
	memset(&cipher, 0, sizeof(cipher));

	/* Destroy temporary data. */
	memset(buf, 0, sizeof(buf));
	buffer_free(&buffer);

	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
	if (fd < 0)
		return 0;
	if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
	    buffer_len(&encrypted)) {
		debug("Write to key file %.200s failed: %.100s", filename,
		      strerror(errno));
		buffer_free(&encrypted);
		close(fd);
		remove(filename);
		return 0;
	}
	close(fd);
	buffer_free(&encrypted);
	return 1;
}

/* save DSA key in OpenSSL PEM format */

int
save_private_key_dsa(const char *filename, const char *passphrase,
    DSA *dsa, const char *comment)
{
	FILE *fp;
	int fd;
	int success = 1;
	int len = strlen(passphrase);

	if (len > 0 && len <= 4) {
		error("passphrase too short: %d bytes", len);
		errno = 0;
		return 0;
	}
	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
	if (fd < 0) {
		debug("open %s failed", filename);
		return 0;
	}
	fp = fdopen(fd, "w");
	if (fp == NULL ) {
		debug("fdopen %s failed", filename);
		close(fd);
		return 0;
	}
	if (len > 0) {
		if (!PEM_write_DSAPrivateKey(fp, dsa, EVP_des_ede3_cbc(),
		    (char *)passphrase, strlen(passphrase), NULL, NULL))
			success = 0;
	} else {
		if (!PEM_write_DSAPrivateKey(fp, dsa, NULL,
		    NULL, 0, NULL, NULL))
			success = 0;
	}
	fclose(fp);
	return success;
}

int
save_private_key(const char *filename, const char *passphrase, Key *key,
    const char *comment)
{
	switch (key->type) {
	case KEY_RSA:
		return save_private_key_rsa(filename, passphrase, key->rsa, comment);
		break;
	case KEY_DSA:
		return save_private_key_dsa(filename, passphrase, key->dsa, comment);
		break;
	default:
		break;
	}
	return 0;
}

/*
 * Loads the public part of the key file.  Returns 0 if an error was
 * encountered (the file does not exist or is not readable), and non-zero
 * otherwise.
 */

int
load_public_key_rsa(const char *filename, RSA * pub, char **comment_return)
{
	int fd, i;
	off_t len;
	Buffer buffer;
	char *cp;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return 0;
	len = lseek(fd, (off_t) 0, SEEK_END);
	lseek(fd, (off_t) 0, SEEK_SET);

	buffer_init(&buffer);
	buffer_append_space(&buffer, &cp, len);

	if (read(fd, cp, (size_t) len) != (size_t) len) {
		debug("Read from key file %.200s failed: %.100s", filename,
		    strerror(errno));
		buffer_free(&buffer);
		close(fd);
		return 0;
	}
	close(fd);

	/* Check that it is at least big enought to contain the ID string. */
	if (len < strlen(AUTHFILE_ID_STRING) + 1) {
		debug("Bad key file %.200s.", filename);
		buffer_free(&buffer);
		return 0;
	}
	/*
	 * Make sure it begins with the id string.  Consume the id string
	 * from the buffer.
	 */
	for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++)
		if (buffer_get_char(&buffer) != (u_char) AUTHFILE_ID_STRING[i]) {
			debug("Bad key file %.200s.", filename);
			buffer_free(&buffer);
			return 0;
		}
	/* Skip cipher type and reserved data. */
	(void) buffer_get_char(&buffer);	/* cipher type */
	(void) buffer_get_int(&buffer);		/* reserved */

	/* Read the public key from the buffer. */
	buffer_get_int(&buffer);
	/* XXX alloc */
	if (pub->n == NULL)
		pub->n = BN_new();
	buffer_get_bignum(&buffer, pub->n);
	/* XXX alloc */
	if (pub->e == NULL)
		pub->e = BN_new();
	buffer_get_bignum(&buffer, pub->e);
	if (comment_return)
		*comment_return = buffer_get_string(&buffer, NULL);
	/* The encrypted private part is not parsed by this function. */

	buffer_free(&buffer);

	return 1;
}

int
load_public_key(const char *filename, Key * key, char **comment_return)
{
	switch (key->type) {
	case KEY_RSA:
		return load_public_key_rsa(filename, key->rsa, comment_return);
		break;
	case KEY_DSA:
	default:
		break;
	}
	return 0;
}

/*
 * Loads the private key from the file.  Returns 0 if an error is encountered
 * (file does not exist or is not readable, or passphrase is bad). This
 * initializes the private key.
 * Assumes we are called under uid of the owner of the file.
 */

int
load_private_key_rsa(int fd, const char *filename,
    const char *passphrase, RSA * prv, char **comment_return)
{
	int i, check1, check2, cipher_type;
	off_t len;
	Buffer buffer, decrypted;
	char *cp;
	CipherContext cipher;
	BN_CTX *ctx;
	BIGNUM *aux;

	len = lseek(fd, (off_t) 0, SEEK_END);
	lseek(fd, (off_t) 0, SEEK_SET);

	buffer_init(&buffer);
	buffer_append_space(&buffer, &cp, len);

	if (read(fd, cp, (size_t) len) != (size_t) len) {
		debug("Read from key file %.200s failed: %.100s", filename,
		      strerror(errno));
		buffer_free(&buffer);
		close(fd);
		return 0;
	}
	close(fd);

	/* Check that it is at least big enought to contain the ID string. */
	if (len < strlen(AUTHFILE_ID_STRING) + 1) {
		debug("Bad key file %.200s.", filename);
		buffer_free(&buffer);
		return 0;
	}
	/*
	 * Make sure it begins with the id string.  Consume the id string
	 * from the buffer.
	 */
	for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++)
		if (buffer_get_char(&buffer) != (unsigned char) AUTHFILE_ID_STRING[i]) {
			debug("Bad key file %.200s.", filename);
			buffer_free(&buffer);
			return 0;
		}
	/* Read cipher type. */
	cipher_type = buffer_get_char(&buffer);
	(void) buffer_get_int(&buffer);	/* Reserved data. */

	/* Read the public key from the buffer. */
	buffer_get_int(&buffer);
	prv->n = BN_new();
	buffer_get_bignum(&buffer, prv->n);
	prv->e = BN_new();
	buffer_get_bignum(&buffer, prv->e);
	if (comment_return)
		*comment_return = buffer_get_string(&buffer, NULL);
	else
		xfree(buffer_get_string(&buffer, NULL));

	/* Check that it is a supported cipher. */
	if (((cipher_mask1() | SSH_CIPHER_NONE | SSH_AUTHFILE_CIPHER) &
	     (1 << cipher_type)) == 0) {
		debug("Unsupported cipher %.100s used in key file %.200s.",
		      cipher_name(cipher_type), filename);
		buffer_free(&buffer);
		goto fail;
	}
	/* Initialize space for decrypted data. */
	buffer_init(&decrypted);
	buffer_append_space(&decrypted, &cp, buffer_len(&buffer));

	/* Rest of the buffer is encrypted.  Decrypt it using the passphrase. */
	cipher_set_key_string(&cipher, cipher_type, passphrase);
	cipher_decrypt(&cipher, (unsigned char *) cp,
		       (unsigned char *) buffer_ptr(&buffer),
		       buffer_len(&buffer));

	buffer_free(&buffer);

	check1 = buffer_get_char(&decrypted);
	check2 = buffer_get_char(&decrypted);
	if (check1 != buffer_get_char(&decrypted) ||
	    check2 != buffer_get_char(&decrypted)) {
		if (strcmp(passphrase, "") != 0)
			debug("Bad passphrase supplied for key file %.200s.", filename);
		/* Bad passphrase. */
		buffer_free(&decrypted);
fail:
		BN_clear_free(prv->n);
		prv->n = NULL;
		BN_clear_free(prv->e);
		prv->e = NULL;
		if (comment_return)
			xfree(*comment_return);
		return 0;
	}
	/* Read the rest of the private key. */
	prv->d = BN_new();
	buffer_get_bignum(&decrypted, prv->d);
	prv->iqmp = BN_new();
	buffer_get_bignum(&decrypted, prv->iqmp);	/* u */
	/* in SSL and SSH p and q are exchanged */
	prv->q = BN_new();
	buffer_get_bignum(&decrypted, prv->q);		/* p */
	prv->p = BN_new();
	buffer_get_bignum(&decrypted, prv->p);		/* q */

	ctx = BN_CTX_new();
	aux = BN_new();

	BN_sub(aux, prv->q, BN_value_one());
	prv->dmq1 = BN_new();
	BN_mod(prv->dmq1, prv->d, aux, ctx);

	BN_sub(aux, prv->p, BN_value_one());
	prv->dmp1 = BN_new();
	BN_mod(prv->dmp1, prv->d, aux, ctx);

	BN_clear_free(aux);
	BN_CTX_free(ctx);

	buffer_free(&decrypted);

	return 1;
}

int
load_private_key_dsa(int fd, const char *passphrase, Key *k, char **comment_return)
{
	DSA *dsa;
	BIO *in;
	FILE *fp;

	in = BIO_new(BIO_s_file());
	if (in == NULL) {
		error("BIO_new failed");
		return 0;
	}
	fp = fdopen(fd, "r");
	if (fp == NULL) {
		error("fdopen failed");
		return 0;
	}
	BIO_set_fp(in, fp, BIO_NOCLOSE);
	dsa = PEM_read_bio_DSAPrivateKey(in, NULL, NULL, (char *)passphrase);
	if (dsa == NULL) {
		debug("PEM_read_bio_DSAPrivateKey failed");
	} else {
		/* replace k->dsa with loaded key */
		DSA_free(k->dsa);
		k->dsa = dsa;
	}
	BIO_free(in);
	fclose(fp);
	if (comment_return)
		*comment_return = xstrdup("dsa w/o comment");
	debug("read DSA private key done");
#ifdef DEBUG_DSS
	DSA_print_fp(stderr, dsa, 8);
#endif
	return dsa != NULL ? 1 : 0;
}

int
load_private_key(const char *filename, const char *passphrase, Key *key,
    char **comment_return)
{
	int fd;
	int ret = 0;
	struct stat st;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return 0;

#ifndef HAVE_CYGWIN
	/*
	 * check owner and modes.
	 * This won't work on Windows under all circumstances so we drop
	 * that check for now.
	 */
	if (fstat(fd, &st) < 0 ||
	    (st.st_uid != 0 && st.st_uid != getuid()) ||
	    (st.st_mode & 077) != 0) {
		close(fd);
		error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
		error("@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @");
		error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
		error("Bad ownership or mode(0%3.3o) for '%s'.",
		      st.st_mode & 0777, filename);
		error("It is recommended that your private key files are NOT accessible by others.");
		return 0;
	}
#endif
	switch (key->type) {
	case KEY_RSA:
		if (key->rsa->e != NULL) {
			BN_clear_free(key->rsa->e);
			key->rsa->e = NULL;
		}
		if (key->rsa->n != NULL) {
			BN_clear_free(key->rsa->n);
			key->rsa->n = NULL;
		}
		ret = load_private_key_rsa(fd, filename, passphrase,
		     key->rsa, comment_return);
		break;
	case KEY_DSA:
		ret = load_private_key_dsa(fd, passphrase, key, comment_return);
	default:
		break;
	}
	close(fd);
	return ret;
}
Commit	Line	Data
8efc0c15	1	/*
6ae2364d	2	*
5260325f	3	* authfile.c
6ae2364d	4	*
5260325f	5	* Author: Tatu Ylonen <ylo@cs.hut.fi>
6ae2364d	6	*
5260325f	7	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	8	* All rights reserved
6ae2364d	9	*
5260325f	10	* Created: Mon Mar 27 03:52:05 1995 ylo
6ae2364d	11	*
5260325f	12	* This file contains functions for reading and writing identity files, and
5260325f	13	* for reading the passphrase from the user.
6ae2364d	14	*
5260325f	15	*/
8efc0c15	16
8efc0c15	17	#include "includes.h"
74fc9186	18	RCSID("$OpenBSD: authfile.c,v 1.17 2000/06/20 01:39:38 markus Exp $");
8efc0c15	19
8efc0c15	20	#include <openssl/bn.h>
a306f2dd	21	#include <openssl/dsa.h>
	22	#include <openssl/rsa.h>
	23	#include <openssl/pem.h>
	24	#include <openssl/evp.h>
	25
8efc0c15	26	#include "xmalloc.h"
	27	#include "buffer.h"
	28	#include "bufaux.h"
	29	#include "cipher.h"
	30	#include "ssh.h"
a306f2dd	31	#include "key.h"
8efc0c15	32
	33	/* Version identification string for identity files. */
	34	#define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n"
	35
aa3378df	36	/*
	37	* Saves the authentication (private) key in a file, encrypting it with
	38	* passphrase. The identification of the file (lowest 64 bits of n) will
	39	* precede the key to provide identification of the key without needing a
	40	* passphrase.
	41	*/
8efc0c15	42
8efc0c15	43	int
a306f2dd	44	save_private_key_rsa(const char filename, const char passphrase,
a306f2dd	45	RSA key, const char comment)
8efc0c15	46	{
5260325f	47	Buffer buffer, encrypted;
5260325f	48	char buf[100], *cp;
a408af76	49	int fd, i;
5260325f	50	CipherContext cipher;
	51	int cipher_type;
	52	u_int32_t rand;
	53
aa3378df	54	/*
	55	* If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
	56	* to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
	57	*/
5260325f	58	if (strcmp(passphrase, "") == 0)
	59	cipher_type = SSH_CIPHER_NONE;
	60	else
	61	cipher_type = SSH_AUTHFILE_CIPHER;
	62
	63	/* This buffer is used to built the secret part of the private key. */
	64	buffer_init(&buffer);
	65
	66	/* Put checkbytes for checking passphrase validity. */
	67	rand = arc4random();
	68	buf[0] = rand & 0xff;
	69	buf[1] = (rand >> 8) & 0xff;
	70	buf[2] = buf[0];
	71	buf[3] = buf[1];
	72	buffer_append(&buffer, buf, 4);
	73
aa3378df	74	/*
	75	* Store the private key (n and e will not be stored because they
	76	* will be stored in plain text, and storing them also in encrypted
	77	* format would just give known plaintext).
	78	*/
5260325f	79	buffer_put_bignum(&buffer, key->d);
	80	buffer_put_bignum(&buffer, key->iqmp);
	81	buffer_put_bignum(&buffer, key->q); /* reverse from SSL p */
	82	buffer_put_bignum(&buffer, key->p); /* reverse from SSL q */
	83
	84	/* Pad the part to be encrypted until its size is a multiple of 8. */
	85	while (buffer_len(&buffer) % 8 != 0)
	86	buffer_put_char(&buffer, 0);
	87
	88	/* This buffer will be used to contain the data in the file. */
	89	buffer_init(&encrypted);
	90
	91	/* First store keyfile id string. */
	92	cp = AUTHFILE_ID_STRING;
	93	for (i = 0; cp[i]; i++)
	94	buffer_put_char(&encrypted, cp[i]);
	95	buffer_put_char(&encrypted, 0);
	96
	97	/* Store cipher type. */
	98	buffer_put_char(&encrypted, cipher_type);
	99	buffer_put_int(&encrypted, 0); /* For future extension */
	100
	101	/* Store public key. This will be in plain text. */
	102	buffer_put_int(&encrypted, BN_num_bits(key->n));
	103	buffer_put_bignum(&encrypted, key->n);
	104	buffer_put_bignum(&encrypted, key->e);
	105	buffer_put_string(&encrypted, comment, strlen(comment));
	106
	107	/* Allocate space for the private part of the key in the buffer. */
	108	buffer_append_space(&encrypted, &cp, buffer_len(&buffer));
	109
8ce64345	110	cipher_set_key_string(&cipher, cipher_type, passphrase);
5260325f	111	cipher_encrypt(&cipher, (unsigned char *) cp,
	112	(unsigned char *) buffer_ptr(&buffer),
	113	buffer_len(&buffer));
	114	memset(&cipher, 0, sizeof(cipher));
	115
	116	/* Destroy temporary data. */
	117	memset(buf, 0, sizeof(buf));
	118	buffer_free(&buffer);
	119
a408af76	120	fd = open(filename, O_WRONLY \| O_CREAT \| O_TRUNC, 0600);
a408af76	121	if (fd < 0)
5260325f	122	return 0;
a408af76	123	if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
5260325f	124	buffer_len(&encrypted)) {
	125	debug("Write to key file %.200s failed: %.100s", filename,
	126	strerror(errno));
	127	buffer_free(&encrypted);
a408af76	128	close(fd);
5260325f	129	remove(filename);
	130	return 0;
	131	}
a408af76	132	close(fd);
5260325f	133	buffer_free(&encrypted);
5260325f	134	return 1;
8efc0c15	135	}
8efc0c15	136
a306f2dd	137	/* save DSA key in OpenSSL PEM format */
	138
	139	int
	140	save_private_key_dsa(const char filename, const char passphrase,
	141	DSA dsa, const char comment)
	142	{
	143	FILE *fp;
	144	int fd;
	145	int success = 1;
	146	int len = strlen(passphrase);
	147
	148	if (len > 0 && len <= 4) {
	149	error("passphrase too short: %d bytes", len);
	150	errno = 0;
	151	return 0;
	152	}
	153	fd = open(filename, O_WRONLY \| O_CREAT \| O_TRUNC, 0600);
	154	if (fd < 0) {
	155	debug("open %s failed", filename);
	156	return 0;
	157	}
	158	fp = fdopen(fd, "w");
	159	if (fp == NULL ) {
	160	debug("fdopen %s failed", filename);
	161	close(fd);
	162	return 0;
	163	}
	164	if (len > 0) {
	165	if (!PEM_write_DSAPrivateKey(fp, dsa, EVP_des_ede3_cbc(),
	166	(char *)passphrase, strlen(passphrase), NULL, NULL))
	167	success = 0;
	168	} else {
	169	if (!PEM_write_DSAPrivateKey(fp, dsa, NULL,
	170	NULL, 0, NULL, NULL))
	171	success = 0;
	172	}
	173	fclose(fp);
	174	return success;
	175	}
	176
	177	int
	178	save_private_key(const char filename, const char passphrase, Key *key,
	179	const char *comment)
	180	{
	181	switch (key->type) {
	182	case KEY_RSA:
	183	return save_private_key_rsa(filename, passphrase, key->rsa, comment);
	184	break;
	185	case KEY_DSA:
	186	return save_private_key_dsa(filename, passphrase, key->dsa, comment);
	187	break;
	188	default:
	189	break;
	190	}
	191	return 0;
	192	}
	193
aa3378df	194	/*
	195	* Loads the public part of the key file. Returns 0 if an error was
	196	* encountered (the file does not exist or is not readable), and non-zero
	197	* otherwise.
	198	*/
8efc0c15	199
8efc0c15	200	int
a306f2dd	201	load_public_key_rsa(const char filename, RSA pub, char **comment_return)
8efc0c15	202	{
a408af76	203	int fd, i;
5260325f	204	off_t len;
	205	Buffer buffer;
	206	char *cp;
	207
a408af76	208	fd = open(filename, O_RDONLY);
a408af76	209	if (fd < 0)
5260325f	210	return 0;
a408af76	211	len = lseek(fd, (off_t) 0, SEEK_END);
a408af76	212	lseek(fd, (off_t) 0, SEEK_SET);
5260325f	213
	214	buffer_init(&buffer);
	215	buffer_append_space(&buffer, &cp, len);
	216
a408af76	217	if (read(fd, cp, (size_t) len) != (size_t) len) {
5260325f	218	debug("Read from key file %.200s failed: %.100s", filename,
a306f2dd	219	strerror(errno));
5260325f	220	buffer_free(&buffer);
a408af76	221	close(fd);
5260325f	222	return 0;
5260325f	223	}
a408af76	224	close(fd);
5260325f	225
	226	/* Check that it is at least big enought to contain the ID string. */
	227	if (len < strlen(AUTHFILE_ID_STRING) + 1) {
	228	debug("Bad key file %.200s.", filename);
	229	buffer_free(&buffer);
	230	return 0;
	231	}
aa3378df	232	/*
	233	* Make sure it begins with the id string. Consume the id string
	234	* from the buffer.
	235	*/
5260325f	236	for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++)
a408af76	237	if (buffer_get_char(&buffer) != (u_char) AUTHFILE_ID_STRING[i]) {
5260325f	238	debug("Bad key file %.200s.", filename);
	239	buffer_free(&buffer);
	240	return 0;
	241	}
	242	/* Skip cipher type and reserved data. */
	243	(void) buffer_get_char(&buffer); /* cipher type */
	244	(void) buffer_get_int(&buffer); /* reserved */
	245
	246	/* Read the public key from the buffer. */
	247	buffer_get_int(&buffer);
a306f2dd	248	/* XXX alloc */
	249	if (pub->n == NULL)
	250	pub->n = BN_new();
5260325f	251	buffer_get_bignum(&buffer, pub->n);
a306f2dd	252	/* XXX alloc */
	253	if (pub->e == NULL)
	254	pub->e = BN_new();
5260325f	255	buffer_get_bignum(&buffer, pub->e);
	256	if (comment_return)
	257	*comment_return = buffer_get_string(&buffer, NULL);
	258	/* The encrypted private part is not parsed by this function. */
	259
8efc0c15	260	buffer_free(&buffer);
5260325f	261
5260325f	262	return 1;
8efc0c15	263	}
8efc0c15	264
a306f2dd	265	int
	266	load_public_key(const char filename, Key key, char **comment_return)
	267	{
	268	switch (key->type) {
	269	case KEY_RSA:
	270	return load_public_key_rsa(filename, key->rsa, comment_return);
	271	break;
	272	case KEY_DSA:
	273	default:
	274	break;
	275	}
	276	return 0;
	277	}
	278
aa3378df	279	/*
	280	* Loads the private key from the file. Returns 0 if an error is encountered
	281	* (file does not exist or is not readable, or passphrase is bad). This
	282	* initializes the private key.
	283	* Assumes we are called under uid of the owner of the file.
	284	*/
8efc0c15	285
8efc0c15	286	int
a306f2dd	287	load_private_key_rsa(int fd, const char *filename,
a306f2dd	288	const char passphrase, RSA prv, char **comment_return)
8efc0c15	289	{
a306f2dd	290	int i, check1, check2, cipher_type;
5260325f	291	off_t len;
	292	Buffer buffer, decrypted;
	293	char *cp;
	294	CipherContext cipher;
	295	BN_CTX *ctx;
	296	BIGNUM *aux;
5260325f	297
a408af76	298	len = lseek(fd, (off_t) 0, SEEK_END);
a408af76	299	lseek(fd, (off_t) 0, SEEK_SET);
5260325f	300
	301	buffer_init(&buffer);
	302	buffer_append_space(&buffer, &cp, len);
	303
a408af76	304	if (read(fd, cp, (size_t) len) != (size_t) len) {
5260325f	305	debug("Read from key file %.200s failed: %.100s", filename,
	306	strerror(errno));
	307	buffer_free(&buffer);
a408af76	308	close(fd);
5260325f	309	return 0;
5260325f	310	}
a408af76	311	close(fd);
5260325f	312
	313	/* Check that it is at least big enought to contain the ID string. */
	314	if (len < strlen(AUTHFILE_ID_STRING) + 1) {
	315	debug("Bad key file %.200s.", filename);
	316	buffer_free(&buffer);
	317	return 0;
	318	}
aa3378df	319	/*
	320	* Make sure it begins with the id string. Consume the id string
	321	* from the buffer.
	322	*/
5260325f	323	for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++)
	324	if (buffer_get_char(&buffer) != (unsigned char) AUTHFILE_ID_STRING[i]) {
	325	debug("Bad key file %.200s.", filename);
	326	buffer_free(&buffer);
	327	return 0;
	328	}
	329	/* Read cipher type. */
	330	cipher_type = buffer_get_char(&buffer);
	331	(void) buffer_get_int(&buffer); /* Reserved data. */
	332
	333	/* Read the public key from the buffer. */
	334	buffer_get_int(&buffer);
	335	prv->n = BN_new();
	336	buffer_get_bignum(&buffer, prv->n);
	337	prv->e = BN_new();
	338	buffer_get_bignum(&buffer, prv->e);
	339	if (comment_return)
	340	*comment_return = buffer_get_string(&buffer, NULL);
	341	else
	342	xfree(buffer_get_string(&buffer, NULL));
	343
	344	/* Check that it is a supported cipher. */
8ce64345	345	if (((cipher_mask1() \| SSH_CIPHER_NONE \| SSH_AUTHFILE_CIPHER) &
5260325f	346	(1 << cipher_type)) == 0) {
	347	debug("Unsupported cipher %.100s used in key file %.200s.",
	348	cipher_name(cipher_type), filename);
	349	buffer_free(&buffer);
	350	goto fail;
	351	}
	352	/* Initialize space for decrypted data. */
	353	buffer_init(&decrypted);
	354	buffer_append_space(&decrypted, &cp, buffer_len(&buffer));
	355
	356	/* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
8ce64345	357	cipher_set_key_string(&cipher, cipher_type, passphrase);
5260325f	358	cipher_decrypt(&cipher, (unsigned char *) cp,
	359	(unsigned char *) buffer_ptr(&buffer),
	360	buffer_len(&buffer));
	361
8efc0c15	362	buffer_free(&buffer);
5260325f	363
	364	check1 = buffer_get_char(&decrypted);
	365	check2 = buffer_get_char(&decrypted);
	366	if (check1 != buffer_get_char(&decrypted) \|\|
	367	check2 != buffer_get_char(&decrypted)) {
	368	if (strcmp(passphrase, "") != 0)
	369	debug("Bad passphrase supplied for key file %.200s.", filename);
	370	/* Bad passphrase. */
	371	buffer_free(&decrypted);
	372	fail:
	373	BN_clear_free(prv->n);
a306f2dd	374	prv->n = NULL;
5260325f	375	BN_clear_free(prv->e);
a306f2dd	376	prv->e = NULL;
5260325f	377	if (comment_return)
	378	xfree(*comment_return);
	379	return 0;
	380	}
	381	/* Read the rest of the private key. */
	382	prv->d = BN_new();
	383	buffer_get_bignum(&decrypted, prv->d);
	384	prv->iqmp = BN_new();
	385	buffer_get_bignum(&decrypted, prv->iqmp); /* u */
	386	/* in SSL and SSH p and q are exchanged */
	387	prv->q = BN_new();
	388	buffer_get_bignum(&decrypted, prv->q); /* p */
	389	prv->p = BN_new();
	390	buffer_get_bignum(&decrypted, prv->p); /* q */
	391
	392	ctx = BN_CTX_new();
	393	aux = BN_new();
	394
	395	BN_sub(aux, prv->q, BN_value_one());
	396	prv->dmq1 = BN_new();
	397	BN_mod(prv->dmq1, prv->d, aux, ctx);
	398
	399	BN_sub(aux, prv->p, BN_value_one());
	400	prv->dmp1 = BN_new();
	401	BN_mod(prv->dmp1, prv->d, aux, ctx);
	402
	403	BN_clear_free(aux);
	404	BN_CTX_free(ctx);
	405
	406	buffer_free(&decrypted);
	407
	408	return 1;
8efc0c15	409	}
a306f2dd	410
	411	int
	412	load_private_key_dsa(int fd, const char passphrase, Key k, char **comment_return)
	413	{
	414	DSA *dsa;
	415	BIO *in;
	416	FILE *fp;
	417
	418	in = BIO_new(BIO_s_file());
	419	if (in == NULL) {
	420	error("BIO_new failed");
	421	return 0;
	422	}
	423	fp = fdopen(fd, "r");
	424	if (fp == NULL) {
	425	error("fdopen failed");
	426	return 0;
	427	}
	428	BIO_set_fp(in, fp, BIO_NOCLOSE);
	429	dsa = PEM_read_bio_DSAPrivateKey(in, NULL, NULL, (char *)passphrase);
	430	if (dsa == NULL) {
	431	debug("PEM_read_bio_DSAPrivateKey failed");
	432	} else {
	433	/* replace k->dsa with loaded key */
	434	DSA_free(k->dsa);
	435	k->dsa = dsa;
	436	}
	437	BIO_free(in);
	438	fclose(fp);
	439	if (comment_return)
	440	*comment_return = xstrdup("dsa w/o comment");
	441	debug("read DSA private key done");
	442	#ifdef DEBUG_DSS
	443	DSA_print_fp(stderr, dsa, 8);
	444	#endif
	445	return dsa != NULL ? 1 : 0;
	446	}
	447
	448	int
	449	load_private_key(const char filename, const char passphrase, Key *key,
	450	char **comment_return)
	451	{
	452	int fd;
	453	int ret = 0;
	454	struct stat st;
	455
	456	fd = open(filename, O_RDONLY);
	457	if (fd < 0)
	458	return 0;
	459
3c62e7eb	460	#ifndef HAVE_CYGWIN
	461	/*
	462	* check owner and modes.
	463	* This won't work on Windows under all circumstances so we drop
	464	* that check for now.
	465	*/
a306f2dd	466	if (fstat(fd, &st) < 0 \|\|
	467	(st.st_uid != 0 && st.st_uid != getuid()) \|\|
	468	(st.st_mode & 077) != 0) {
	469	close(fd);
	470	error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
	471	error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
	472	error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
	473	error("Bad ownership or mode(0%3.3o) for '%s'.",
	474	st.st_mode & 0777, filename);
	475	error("It is recommended that your private key files are NOT accessible by others.");
	476	return 0;
	477	}
3c62e7eb	478	#endif
a306f2dd	479	switch (key->type) {
	480	case KEY_RSA:
	481	if (key->rsa->e != NULL) {
	482	BN_clear_free(key->rsa->e);
	483	key->rsa->e = NULL;
	484	}
	485	if (key->rsa->n != NULL) {
	486	BN_clear_free(key->rsa->n);
	487	key->rsa->n = NULL;
	488	}
	489	ret = load_private_key_rsa(fd, filename, passphrase,
	490	key->rsa, comment_return);
	491	break;
	492	case KEY_DSA:
	493	ret = load_private_key_dsa(fd, passphrase, key, comment_return);
	494	default:
	495	break;
	496	}
	497	close(fd);
	498	return ret;
	499	}