text: /* $OpenBSD: ssh-keygen.c,v 1.225 2013/02/10 23:32:10 djm Exp $ */
  /*
   * Author: Tatu Ylonen <ylo@cs.hut.fi>
   * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   *                    All rights reserved
   * Identity and host key generation and maintenance.
   *
   * 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".
   */
  
  #include "includes.h"
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/stat.h>
  #include <sys/param.h>
  
  #include <openssl/evp.h>
  #include <openssl/pem.h>
  #include "openbsd-compat/openssl-compat.h"
  
  #include <errno.h>
  #include <fcntl.h>
  #include <netdb.h>
  #ifdef HAVE_PATHS_H
  # include <paths.h>
  #endif
  #include <pwd.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include "xmalloc.h"
  #include "key.h"
  #include "rsa.h"
  #include "authfile.h"
  #include "uuencode.h"
  #include "buffer.h"
  #include "pathnames.h"
  #include "log.h"
  #include "misc.h"
  #include "match.h"
  #include "hostfile.h"
  #include "dns.h"
  #include "ssh.h"
  #include "ssh2.h"
  #include "ssh-pkcs11.h"
  #include "atomicio.h"
  #include "krl.h"
  
  /* Number of bits in the RSA/DSA key.  This value can be set on the command line. */
  #define DEFAULT_BITS		2048
  #define DEFAULT_BITS_DSA	1024
  #define DEFAULT_BITS_ECDSA	256
  u_int32_t bits = 0;
  
  /*
   * Flag indicating that we just want to change the passphrase.  This can be
   * set on the command line.
   */
  int change_passphrase = 0;
  
  /*
   * Flag indicating that we just want to change the comment.  This can be set
   * on the command line.
   */
  int change_comment = 0;
  
  int quiet = 0;
  
  int log_level = SYSLOG_LEVEL_INFO;
  
  /* Flag indicating that we want to hash a known_hosts file */
  int hash_hosts = 0;
  /* Flag indicating that we want lookup a host in known_hosts file */
  int find_host = 0;
  /* Flag indicating that we want to delete a host from a known_hosts file */
  int delete_host = 0;
  
  /* Flag indicating that we want to show the contents of a certificate */
  int show_cert = 0;
  
  /* Flag indicating that we just want to see the key fingerprint */
  int print_fingerprint = 0;
  int print_bubblebabble = 0;
  
  /* The identity file name, given on the command line or entered by the user. */
  char identity_file[1024];
  int have_identity = 0;
  
  /* This is set to the passphrase if given on the command line. */
  char *identity_passphrase = NULL;
  
  /* This is set to the new passphrase if given on the command line. */
  char *identity_new_passphrase = NULL;
  
  /* This is set to the new comment if given on the command line. */
  char *identity_comment = NULL;
  
  /* Path to CA key when certifying keys. */
  char *ca_key_path = NULL;
  
  /* Certificate serial number */
  unsigned long long cert_serial = 0;
  
  /* Key type when certifying */
  u_int cert_key_type = SSH2_CERT_TYPE_USER;
  
  /* "key ID" of signed key */
  char *cert_key_id = NULL;
  
  /* Comma-separated list of principal names for certifying keys */
  char *cert_principals = NULL;
  
  /* Validity period for certificates */
  u_int64_t cert_valid_from = 0;
  u_int64_t cert_valid_to = ~0ULL;
  
  /* Certificate options */
  #define CERTOPT_X_FWD	(1)
  #define CERTOPT_AGENT_FWD	(1<<1)
  #define CERTOPT_PORT_FWD	(1<<2)
  #define CERTOPT_PTY		(1<<3)
  #define CERTOPT_USER_RC	(1<<4)
  #define CERTOPT_DEFAULT	(CERTOPT_X_FWD|CERTOPT_AGENT_FWD| \
  			 CERTOPT_PORT_FWD|CERTOPT_PTY|CERTOPT_USER_RC)
  u_int32_t certflags_flags = CERTOPT_DEFAULT;
  char *certflags_command = NULL;
  char *certflags_src_addr = NULL;
  
  /* Conversion to/from various formats */
  int convert_to = 0;
  int convert_from = 0;
  enum {
  	FMT_RFC4716,
  	FMT_PKCS8,
  	FMT_PEM
  } convert_format = FMT_RFC4716;
  int print_public = 0;
  int print_generic = 0;
  
  char *key_type_name = NULL;
  
  /* Load key from this PKCS#11 provider */
  char *pkcs11provider = NULL;
  
  /* argv0 */
  extern char *__progname;
  
  char hostname[MAXHOSTNAMELEN];
  
  /* moduli.c */
  int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
  int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long,
      unsigned long);
  
  static void
  type_bits_valid(int type, u_int32_t *bitsp)
  {
  	u_int maxbits;
  
  	if (type == KEY_UNSPEC) {
  		fprintf(stderr, "unknown key type %s\n", key_type_name);
  		exit(1);
  	}
  	if (*bitsp == 0) {
  		if (type == KEY_DSA)
  			*bitsp = DEFAULT_BITS_DSA;
  		else if (type == KEY_ECDSA)
  			*bitsp = DEFAULT_BITS_ECDSA;
  		else
  			*bitsp = DEFAULT_BITS;
  	}
  	maxbits = (type == KEY_DSA) ?
  	    OPENSSL_DSA_MAX_MODULUS_BITS : OPENSSL_RSA_MAX_MODULUS_BITS;
  	if (*bitsp > maxbits) {
  		fprintf(stderr, "key bits exceeds maximum %d\n", maxbits);
  		exit(1);
  	}
  	if (type == KEY_DSA && *bitsp != 1024)
  		fatal("DSA keys must be 1024 bits");
  	else if (type != KEY_ECDSA && *bitsp < 768)
  		fatal("Key must at least be 768 bits");
  	else if (type == KEY_ECDSA && key_ecdsa_bits_to_nid(*bitsp) == -1)
  		fatal("Invalid ECDSA key length - valid lengths are "
  		    "256, 384 or 521 bits");
  }
  
  static void
  ask_filename(struct passwd *pw, const char *prompt)
  {
  	char buf[1024];
  	char *name = NULL;
  
  	if (key_type_name == NULL)
  		name = _PATH_SSH_CLIENT_ID_RSA;
  	else {
  		switch (key_type_from_name(key_type_name)) {
  		case KEY_RSA1:
  			name = _PATH_SSH_CLIENT_IDENTITY;
  			break;
  		case KEY_DSA_CERT:
  		case KEY_DSA_CERT_V00:
  		case KEY_DSA:
  			name = _PATH_SSH_CLIENT_ID_DSA;
  			break;
  #ifdef OPENSSL_HAS_ECC
  		case KEY_ECDSA_CERT:
  		case KEY_ECDSA:
  			name = _PATH_SSH_CLIENT_ID_ECDSA;
  			break;
  #endif
  		case KEY_RSA_CERT:
  		case KEY_RSA_CERT_V00:
  		case KEY_RSA:
  			name = _PATH_SSH_CLIENT_ID_RSA;
  			break;
  		default:
  			fprintf(stderr, "bad key type\n");
  			exit(1);
  			break;
  		}
  	}
  	snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
  	fprintf(stderr, "%s (%s): ", prompt, identity_file);
  	if (fgets(buf, sizeof(buf), stdin) == NULL)
  		exit(1);
  	buf[strcspn(buf, "\n")] = '\0';
  	if (strcmp(buf, "") != 0)
  		strlcpy(identity_file, buf, sizeof(identity_file));
  	have_identity = 1;
  }
  
  static Key *
  load_identity(char *filename)
  {
  	char *pass;
  	Key *prv;
  
  	prv = key_load_private(filename, "", NULL);
  	if (prv == NULL) {
  		if (identity_passphrase)
  			pass = xstrdup(identity_passphrase);
  		else
  			pass = read_passphrase("Enter passphrase: ",
  			    RP_ALLOW_STDIN);
  		prv = key_load_private(filename, pass, NULL);
  		memset(pass, 0, strlen(pass));
  		xfree(pass);
  	}
  	return prv;
  }
  
  #define SSH_COM_PUBLIC_BEGIN		"---- BEGIN SSH2 PUBLIC KEY ----"
  #define SSH_COM_PUBLIC_END		"---- END SSH2 PUBLIC KEY ----"
  #define SSH_COM_PRIVATE_BEGIN		"---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
  #define	SSH_COM_PRIVATE_KEY_MAGIC	0x3f6ff9eb
  
  static void
  do_convert_to_ssh2(struct passwd *pw, Key *k)
  {
  	u_int len;
  	u_char *blob;
  	char comment[61];
  
  	if (k->type == KEY_RSA1) {
  		fprintf(stderr, "version 1 keys are not supported\n");
  		exit(1);
  	}
  	if (key_to_blob(k, &blob, &len) <= 0) {
  		fprintf(stderr, "key_to_blob failed\n");
  		exit(1);
  	}
  	/* Comment + surrounds must fit into 72 chars (RFC 4716 sec 3.3) */
  	snprintf(comment, sizeof(comment),
  	    "%u-bit %s, converted by %s@%s from OpenSSH",
  	    key_size(k), key_type(k),
  	    pw->pw_name, hostname);
  
  	fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
  	fprintf(stdout, "Comment: \"%s\"\n", comment);
  	dump_base64(stdout, blob, len);
  	fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
  	key_free(k);
  	xfree(blob);
  	exit(0);
  }
  
  static void
  do_convert_to_pkcs8(Key *k)
  {
  	switch (key_type_plain(k->type)) {
  	case KEY_RSA1:
  	case KEY_RSA:
  		if (!PEM_write_RSA_PUBKEY(stdout, k->rsa))
  			fatal("PEM_write_RSA_PUBKEY failed");
  		break;
  	case KEY_DSA:
  		if (!PEM_write_DSA_PUBKEY(stdout, k->dsa))
  			fatal("PEM_write_DSA_PUBKEY failed");
  		break;
  #ifdef OPENSSL_HAS_ECC
  	case KEY_ECDSA:
  		if (!PEM_write_EC_PUBKEY(stdout, k->ecdsa))
  			fatal("PEM_write_EC_PUBKEY failed");
  		break;
  #endif
  	default:
  		fatal("%s: unsupported key type %s", __func__, key_type(k));
  	}
  	exit(0);
  }
  
  static void
  do_convert_to_pem(Key *k)
  {
  	switch (key_type_plain(k->type)) {
  	case KEY_RSA1:
  	case KEY_RSA:
  		if (!PEM_write_RSAPublicKey(stdout, k->rsa))
  			fatal("PEM_write_RSAPublicKey failed");
  		break;
  #if notyet /* OpenSSH 0.9.8 lacks this function */
  	case KEY_DSA:
  		if (!PEM_write_DSAPublicKey(stdout, k->dsa))
  			fatal("PEM_write_DSAPublicKey failed");
  		break;
  #endif
  	/* XXX ECDSA? */
  	default:
  		fatal("%s: unsupported key type %s", __func__, key_type(k));
  	}
  	exit(0);
  }
  
  static void
  do_convert_to(struct passwd *pw)
  {
  	Key *k;
  	struct stat st;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  	if ((k = key_load_public(identity_file, NULL)) == NULL) {
  		if ((k = load_identity(identity_file)) == NULL) {
  			fprintf(stderr, "load failed\n");
  			exit(1);
  		}
  	}
  
  	switch (convert_format) {
  	case FMT_RFC4716:
  		do_convert_to_ssh2(pw, k);
  		break;
  	case FMT_PKCS8:
  		do_convert_to_pkcs8(k);
  		break;
  	case FMT_PEM:
  		do_convert_to_pem(k);
  		break;
  	default:
  		fatal("%s: unknown key format %d", __func__, convert_format);
  	}
  	exit(0);
  }
  
  static void
  buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
  {
  	u_int bignum_bits = buffer_get_int(b);
  	u_int bytes = (bignum_bits + 7) / 8;
  
  	if (buffer_len(b) < bytes)
  		fatal("buffer_get_bignum_bits: input buffer too small: "
  		    "need %d have %d", bytes, buffer_len(b));
  	if (BN_bin2bn(buffer_ptr(b), bytes, value) == NULL)
  		fatal("buffer_get_bignum_bits: BN_bin2bn failed");
  	buffer_consume(b, bytes);
  }
  
  static Key *
  do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
  {
  	Buffer b;
  	Key *key = NULL;
  	char *type, *cipher;
  	u_char *sig, data[] = "abcde12345";
  	int magic, rlen, ktype, i1, i2, i3, i4;
  	u_int slen;
  	u_long e;
  
  	buffer_init(&b);
  	buffer_append(&b, blob, blen);
  
  	magic = buffer_get_int(&b);
  	if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
  		error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
  		buffer_free(&b);
  		return NULL;
  	}
  	i1 = buffer_get_int(&b);
  	type   = buffer_get_string(&b, NULL);
  	cipher = buffer_get_string(&b, NULL);
  	i2 = buffer_get_int(&b);
  	i3 = buffer_get_int(&b);
  	i4 = buffer_get_int(&b);
  	debug("ignore (%d %d %d %d)", i1, i2, i3, i4);
  	if (strcmp(cipher, "none") != 0) {
  		error("unsupported cipher %s", cipher);
  		xfree(cipher);
  		buffer_free(&b);
  		xfree(type);
  		return NULL;
  	}
  	xfree(cipher);
  
  	if (strstr(type, "dsa")) {
  		ktype = KEY_DSA;
  	} else if (strstr(type, "rsa")) {
  		ktype = KEY_RSA;
  	} else {
  		buffer_free(&b);
  		xfree(type);
  		return NULL;
  	}
  	key = key_new_private(ktype);
  	xfree(type);
  
  	switch (key->type) {
  	case KEY_DSA:
  		buffer_get_bignum_bits(&b, key->dsa->p);
  		buffer_get_bignum_bits(&b, key->dsa->g);
  		buffer_get_bignum_bits(&b, key->dsa->q);
  		buffer_get_bignum_bits(&b, key->dsa->pub_key);
  		buffer_get_bignum_bits(&b, key->dsa->priv_key);
  		break;
  	case KEY_RSA:
  		e = buffer_get_char(&b);
  		debug("e %lx", e);
  		if (e < 30) {
  			e <<= 8;
  			e += buffer_get_char(&b);
  			debug("e %lx", e);
  			e <<= 8;
  			e += buffer_get_char(&b);
  			debug("e %lx", e);
  		}
  		if (!BN_set_word(key->rsa->e, e)) {
  			buffer_free(&b);
  			key_free(key);
  			return NULL;
  		}
  		buffer_get_bignum_bits(&b, key->rsa->d);
  		buffer_get_bignum_bits(&b, key->rsa->n);
  		buffer_get_bignum_bits(&b, key->rsa->iqmp);
  		buffer_get_bignum_bits(&b, key->rsa->q);
  		buffer_get_bignum_bits(&b, key->rsa->p);
  		rsa_generate_additional_parameters(key->rsa);
  		break;
  	}
  	rlen = buffer_len(&b);
  	if (rlen != 0)
  		error("do_convert_private_ssh2_from_blob: "
  		    "remaining bytes in key blob %d", rlen);
  	buffer_free(&b);
  
  	/* try the key */
  	key_sign(key, &sig, &slen, data, sizeof(data));
  	key_verify(key, sig, slen, data, sizeof(data));
  	xfree(sig);
  	return key;
  }
  
  static int
  get_line(FILE *fp, char *line, size_t len)
  {
  	int c;
  	size_t pos = 0;
  
  	line[0] = '\0';
  	while ((c = fgetc(fp)) != EOF) {
  		if (pos >= len - 1) {
  			fprintf(stderr, "input line too long.\n");
  			exit(1);
  		}
  		switch (c) {
  		case '\r':
  			c = fgetc(fp);
  			if (c != EOF && c != '\n' && ungetc(c, fp) == EOF) {
  				fprintf(stderr, "unget: %s\n", strerror(errno));
  				exit(1);
  			}
  			return pos;
  		case '\n':
  			return pos;
  		}
  		line[pos++] = c;
  		line[pos] = '\0';
  	}
  	/* We reached EOF */
  	return -1;
  }
  
  static void
  do_convert_from_ssh2(struct passwd *pw, Key **k, int *private)
  {
  	int blen;
  	u_int len;
  	char line[1024];
  	u_char blob[8096];
  	char encoded[8096];
  	int escaped = 0;
  	FILE *fp;
  
  	if ((fp = fopen(identity_file, "r")) == NULL)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  	encoded[0] = '\0';
  	while ((blen = get_line(fp, line, sizeof(line))) != -1) {
  		if (line[blen - 1] == '\\')
  			escaped++;
  		if (strncmp(line, "----", 4) == 0 ||
  		    strstr(line, ": ") != NULL) {
  			if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
  				*private = 1;
  			if (strstr(line, " END ") != NULL) {
  				break;
  			}
  			/* fprintf(stderr, "ignore: %s", line); */
  			continue;
  		}
  		if (escaped) {
  			escaped--;
  			/* fprintf(stderr, "escaped: %s", line); */
  			continue;
  		}
  		strlcat(encoded, line, sizeof(encoded));
  	}
  	len = strlen(encoded);
  	if (((len % 4) == 3) &&
  	    (encoded[len-1] == '=') &&
  	    (encoded[len-2] == '=') &&
  	    (encoded[len-3] == '='))
  		encoded[len-3] = '\0';
  	blen = uudecode(encoded, blob, sizeof(blob));
  	if (blen < 0) {
  		fprintf(stderr, "uudecode failed.\n");
  		exit(1);
  	}
  	*k = *private ?
  	    do_convert_private_ssh2_from_blob(blob, blen) :
  	    key_from_blob(blob, blen);
  	if (*k == NULL) {
  		fprintf(stderr, "decode blob failed.\n");
  		exit(1);
  	}
  	fclose(fp);
  }
  
  static void
  do_convert_from_pkcs8(Key **k, int *private)
  {
  	EVP_PKEY *pubkey;
  	FILE *fp;
  
  	if ((fp = fopen(identity_file, "r")) == NULL)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  	if ((pubkey = PEM_read_PUBKEY(fp, NULL, NULL, NULL)) == NULL) {
  		fatal("%s: %s is not a recognised public key format", __func__,
  		    identity_file);
  	}
  	fclose(fp);
  	switch (EVP_PKEY_type(pubkey->type)) {
  	case EVP_PKEY_RSA:
  		*k = key_new(KEY_UNSPEC);
  		(*k)->type = KEY_RSA;
  		(*k)->rsa = EVP_PKEY_get1_RSA(pubkey);
  		break;
  	case EVP_PKEY_DSA:
  		*k = key_new(KEY_UNSPEC);
  		(*k)->type = KEY_DSA;
  		(*k)->dsa = EVP_PKEY_get1_DSA(pubkey);
  		break;
  #ifdef OPENSSL_HAS_ECC
  	case EVP_PKEY_EC:
  		*k = key_new(KEY_UNSPEC);
  		(*k)->type = KEY_ECDSA;
  		(*k)->ecdsa = EVP_PKEY_get1_EC_KEY(pubkey);
  		(*k)->ecdsa_nid = key_ecdsa_key_to_nid((*k)->ecdsa);
  		break;
  #endif
  	default:
  		fatal("%s: unsupported pubkey type %d", __func__,
  		    EVP_PKEY_type(pubkey->type));
  	}
  	EVP_PKEY_free(pubkey);
  	return;
  }
  
  static void
  do_convert_from_pem(Key **k, int *private)
  {
  	FILE *fp;
  	RSA *rsa;
  #ifdef notyet
  	DSA *dsa;
  #endif
  
  	if ((fp = fopen(identity_file, "r")) == NULL)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  	if ((rsa = PEM_read_RSAPublicKey(fp, NULL, NULL, NULL)) != NULL) {
  		*k = key_new(KEY_UNSPEC);
  		(*k)->type = KEY_RSA;
  		(*k)->rsa = rsa;
  		fclose(fp);
  		return;
  	}
  #if notyet /* OpenSSH 0.9.8 lacks this function */
  	rewind(fp);
  	if ((dsa = PEM_read_DSAPublicKey(fp, NULL, NULL, NULL)) != NULL) {
  		*k = key_new(KEY_UNSPEC);
  		(*k)->type = KEY_DSA;
  		(*k)->dsa = dsa;
  		fclose(fp);
  		return;
  	}
  	/* XXX ECDSA */
  #endif
  	fatal("%s: unrecognised raw private key format", __func__);
  }
  
  static void
  do_convert_from(struct passwd *pw)
  {
  	Key *k = NULL;
  	int private = 0, ok = 0;
  	struct stat st;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  
  	switch (convert_format) {
  	case FMT_RFC4716:
  		do_convert_from_ssh2(pw, &k, &private);
  		break;
  	case FMT_PKCS8:
  		do_convert_from_pkcs8(&k, &private);
  		break;
  	case FMT_PEM:
  		do_convert_from_pem(&k, &private);
  		break;
  	default:
  		fatal("%s: unknown key format %d", __func__, convert_format);
  	}
  
  	if (!private)
  		ok = key_write(k, stdout);
  		if (ok)
  			fprintf(stdout, "\n");
  	else {
  		switch (k->type) {
  		case KEY_DSA:
  			ok = PEM_write_DSAPrivateKey(stdout, k->dsa, NULL,
  			    NULL, 0, NULL, NULL);
  			break;
  #ifdef OPENSSL_HAS_ECC
  		case KEY_ECDSA:
  			ok = PEM_write_ECPrivateKey(stdout, k->ecdsa, NULL,
  			    NULL, 0, NULL, NULL);
  			break;
  #endif
  		case KEY_RSA:
  			ok = PEM_write_RSAPrivateKey(stdout, k->rsa, NULL,
  			    NULL, 0, NULL, NULL);
  			break;
  		default:
  			fatal("%s: unsupported key type %s", __func__,
  			    key_type(k));
  		}
  	}
  
  	if (!ok) {
  		fprintf(stderr, "key write failed\n");
  		exit(1);
  	}
  	key_free(k);
  	exit(0);
  }
  
  static void
  do_print_public(struct passwd *pw)
  {
  	Key *prv;
  	struct stat st;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0) {
  		perror(identity_file);
  		exit(1);
  	}
  	prv = load_identity(identity_file);
  	if (prv == NULL) {
  		fprintf(stderr, "load failed\n");
  		exit(1);
  	}
  	if (!key_write(prv, stdout))
  		fprintf(stderr, "key_write failed");
  	key_free(prv);
  	fprintf(stdout, "\n");
  	exit(0);
  }
  
  static void
  do_download(struct passwd *pw)
  {
  #ifdef ENABLE_PKCS11
  	Key **keys = NULL;
  	int i, nkeys;
  	enum fp_rep rep;
  	enum fp_type fptype;
  	char *fp, *ra;
  
  	fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
  	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
  
  	pkcs11_init(0);
  	nkeys = pkcs11_add_provider(pkcs11provider, NULL, &keys);
  	if (nkeys <= 0)
  		fatal("cannot read public key from pkcs11");
  	for (i = 0; i < nkeys; i++) {
  		if (print_fingerprint) {
  			fp = key_fingerprint(keys[i], fptype, rep);
  			ra = key_fingerprint(keys[i], SSH_FP_MD5,
  			    SSH_FP_RANDOMART);
  			printf("%u %s %s (PKCS11 key)\n", key_size(keys[i]),
  			    fp, key_type(keys[i]));
  			if (log_level >= SYSLOG_LEVEL_VERBOSE)
  				printf("%s\n", ra);
  			xfree(ra);
  			xfree(fp);
  		} else {
  			key_write(keys[i], stdout);
  			fprintf(stdout, "\n");
  		}
  		key_free(keys[i]);
  	}
  	xfree(keys);
  	pkcs11_terminate();
  	exit(0);
  #else
  	fatal("no pkcs11 support");
  #endif /* ENABLE_PKCS11 */
  }
  
  static void
  do_fingerprint(struct passwd *pw)
  {
  	FILE *f;
  	Key *public;
  	char *comment = NULL, *cp, *ep, line[16*1024], *fp, *ra;
  	int i, skip = 0, num = 0, invalid = 1;
  	enum fp_rep rep;
  	enum fp_type fptype;
  	struct stat st;
  
  	fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
  	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0) {
  		perror(identity_file);
  		exit(1);
  	}
  	public = key_load_public(identity_file, &comment);
  	if (public != NULL) {
  		fp = key_fingerprint(public, fptype, rep);
  		ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
  		printf("%u %s %s (%s)\n", key_size(public), fp, comment,
  		    key_type(public));
  		if (log_level >= SYSLOG_LEVEL_VERBOSE)
  			printf("%s\n", ra);
  		key_free(public);
  		xfree(comment);
  		xfree(ra);
  		xfree(fp);
  		exit(0);
  	}
  	if (comment) {
  		xfree(comment);
  		comment = NULL;
  	}
  
  	if ((f = fopen(identity_file, "r")) == NULL)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  
  	while (fgets(line, sizeof(line), f)) {
  		if ((cp = strchr(line, '\n')) == NULL) {
  			error("line %d too long: %.40s...",
  			    num + 1, line);
  			skip = 1;
  			continue;
  		}
  		num++;
  		if (skip) {
  			skip = 0;
  			continue;
  		}
  		*cp = '\0';
  
  		/* Skip leading whitespace, empty and comment lines. */
  		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
  			;
  		if (!*cp || *cp == '\n' || *cp == '#')
  			continue;
  		i = strtol(cp, &ep, 10);
  		if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
  			int quoted = 0;
  			comment = cp;
  			for (; *cp && (quoted || (*cp != ' ' &&
  			    *cp != '\t')); cp++) {
  				if (*cp == '\\' && cp[1] == '"')
  					cp++;	/* Skip both */
  				else if (*cp == '"')
  					quoted = !quoted;
  			}
  			if (!*cp)
  				continue;
  			*cp++ = '\0';
  		}
  		ep = cp;
  		public = key_new(KEY_RSA1);
  		if (key_read(public, &cp) != 1) {
  			cp = ep;
  			key_free(public);
  			public = key_new(KEY_UNSPEC);
  			if (key_read(public, &cp) != 1) {
  				key_free(public);
  				continue;
  			}
  		}
  		comment = *cp ? cp : comment;
  		fp = key_fingerprint(public, fptype, rep);
  		ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
  		printf("%u %s %s (%s)\n", key_size(public), fp,
  		    comment ? comment : "no comment", key_type(public));
  		if (log_level >= SYSLOG_LEVEL_VERBOSE)
  			printf("%s\n", ra);
  		xfree(ra);
  		xfree(fp);
  		key_free(public);
  		invalid = 0;
  	}
  	fclose(f);
  
  	if (invalid) {
  		printf("%s is not a public key file.\n", identity_file);
  		exit(1);
  	}
  	exit(0);
  }
  
  static void
  do_gen_all_hostkeys(struct passwd *pw)
  {
  	struct {
  		char *key_type;
  		char *key_type_display;
  		char *path;
  	} key_types[] = {
  		{ "rsa1", "RSA1", _PATH_HOST_KEY_FILE },
  		{ "rsa", "RSA" ,_PATH_HOST_RSA_KEY_FILE },
  		{ "dsa", "DSA", _PATH_HOST_DSA_KEY_FILE },
  #ifdef OPENSSL_HAS_ECC
  		{ "ecdsa", "ECDSA",_PATH_HOST_ECDSA_KEY_FILE },
  #endif
  		{ NULL, NULL, NULL }
  	};
  
  	int first = 0;
  	struct stat st;
  	Key *private, *public;
  	char comment[1024];
  	int i, type, fd;
  	FILE *f;
  
  	for (i = 0; key_types[i].key_type; i++) {
  		if (stat(key_types[i].path, &st) == 0)
  			continue;
  		if (errno != ENOENT) {
  			printf("Could not stat %s: %s", key_types[i].path,
  			    strerror(errno));
  			first = 0;
  			continue;
  		}
  
  		if (first == 0) {
  			first = 1;
  			printf("%s: generating new host keys: ", __progname);
  		}
  		printf("%s ", key_types[i].key_type_display);
  		fflush(stdout);
  		arc4random_stir();
  		type = key_type_from_name(key_types[i].key_type);
  		strlcpy(identity_file, key_types[i].path, sizeof(identity_file));
  		bits = 0;
  		type_bits_valid(type, &bits);
  		private = key_generate(type, bits);
  		if (private == NULL) {
  			fprintf(stderr, "key_generate failed\n");
  			first = 0;
  			continue;
  		}
  		public  = key_from_private(private);
  		snprintf(comment, sizeof comment, "%s@%s", pw->pw_name,
  		    hostname);
  		if (!key_save_private(private, identity_file, "", comment)) {
  			printf("Saving the key failed: %s.\n", identity_file);
  			key_free(private);
  			key_free(public);
  			first = 0;
  			continue;
  		}
  		key_free(private);
  		arc4random_stir();
  		strlcat(identity_file, ".pub", sizeof(identity_file));
  		fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
  		if (fd == -1) {
  			printf("Could not save your public key in %s\n",
  			    identity_file);
  			key_free(public);
  			first = 0;
  			continue;
  		}
  		f = fdopen(fd, "w");
  		if (f == NULL) {
  			printf("fdopen %s failed\n", identity_file);
  			key_free(public);
  			first = 0;
  			continue;
  		}
  		if (!key_write(public, f)) {
  			fprintf(stderr, "write key failed\n");
  			key_free(public);
  			first = 0;
  			continue;
  		}
  		fprintf(f, " %s\n", comment);
  		fclose(f);
  		key_free(public);
  
  	}
  	if (first != 0)
  		printf("\n");
  }
  
  static void
  printhost(FILE *f, const char *name, Key *public, int ca, int hash)
  {
  	if (print_fingerprint) {
  		enum fp_rep rep;
  		enum fp_type fptype;
  		char *fp, *ra;
  
  		fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
  		rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
  		fp = key_fingerprint(public, fptype, rep);
  		ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
  		printf("%u %s %s (%s)\n", key_size(public), fp, name,
  		    key_type(public));
  		if (log_level >= SYSLOG_LEVEL_VERBOSE)
  			printf("%s\n", ra);
  		xfree(ra);
  		xfree(fp);
  	} else {
  		if (hash && (name = host_hash(name, NULL, 0)) == NULL)
  			fatal("hash_host failed");
  		fprintf(f, "%s%s%s ", ca ? CA_MARKER : "", ca ? " " : "", name);
  		if (!key_write(public, f))
  			fatal("key_write failed");
  		fprintf(f, "\n");
  	}
  }
  
  static void
  do_known_hosts(struct passwd *pw, const char *name)
  {
  	FILE *in, *out = stdout;
  	Key *pub;
  	char *cp, *cp2, *kp, *kp2;
  	char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
  	int c, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;
  	int ca;
  
  	if (!have_identity) {
  		cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
  		if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
  		    sizeof(identity_file))
  			fatal("Specified known hosts path too long");
  		xfree(cp);
  		have_identity = 1;
  	}
  	if ((in = fopen(identity_file, "r")) == NULL)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  
  	/*
  	 * Find hosts goes to stdout, hash and deletions happen in-place
  	 * A corner case is ssh-keygen -HF foo, which should go to stdout
  	 */
  	if (!find_host && (hash_hosts || delete_host)) {
  		if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
  		    strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
  		    strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
  		    strlcat(old, ".old", sizeof(old)) >= sizeof(old))
  			fatal("known_hosts path too long");
  		umask(077);
  		if ((c = mkstemp(tmp)) == -1)
  			fatal("mkstemp: %s", strerror(errno));
  		if ((out = fdopen(c, "w")) == NULL) {
  			c = errno;
  			unlink(tmp);
  			fatal("fdopen: %s", strerror(c));
  		}
  		inplace = 1;
  	}
  
  	while (fgets(line, sizeof(line), in)) {
  		if ((cp = strchr(line, '\n')) == NULL) {
  			error("line %d too long: %.40s...", num + 1, line);
  			skip = 1;
  			invalid = 1;
  			continue;
  		}
  		num++;
  		if (skip) {
  			skip = 0;
  			continue;
  		}
  		*cp = '\0';
  
  		/* Skip leading whitespace, empty and comment lines. */
  		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
  			;
  		if (!*cp || *cp == '\n' || *cp == '#') {
  			if (inplace)
  				fprintf(out, "%s\n", cp);
  			continue;
  		}
  		/* Check whether this is a CA key */
  		if (strncasecmp(cp, CA_MARKER, sizeof(CA_MARKER) - 1) == 0 &&
  		    (cp[sizeof(CA_MARKER) - 1] == ' ' ||
  		    cp[sizeof(CA_MARKER) - 1] == '\t')) {
  			ca = 1;
  			cp += sizeof(CA_MARKER);
  		} else
  			ca = 0;
  
  		/* Find the end of the host name portion. */
  		for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
  			;
  
  		if (*kp == '\0' || *(kp + 1) == '\0') {
  			error("line %d missing key: %.40s...",
  			    num, line);
  			invalid = 1;
  			continue;
  		}
  		*kp++ = '\0';
  		kp2 = kp;
  
  		pub = key_new(KEY_RSA1);
  		if (key_read(pub, &kp) != 1) {
  			kp = kp2;
  			key_free(pub);
  			pub = key_new(KEY_UNSPEC);
  			if (key_read(pub, &kp) != 1) {
  				error("line %d invalid key: %.40s...",
  				    num, line);
  				key_free(pub);
  				invalid = 1;
  				continue;
  			}
  		}
  
  		if (*cp == HASH_DELIM) {
  			if (find_host || delete_host) {
  				cp2 = host_hash(name, cp, strlen(cp));
  				if (cp2 == NULL) {
  					error("line %d: invalid hashed "
  					    "name: %.64s...", num, line);
  					invalid = 1;
  					continue;
  				}
  				c = (strcmp(cp2, cp) == 0);
  				if (find_host && c) {
  					printf("# Host %s found: "
  					    "line %d type %s%s\n", name,
  					    num, key_type(pub),
  					    ca ? " (CA key)" : "");
  					printhost(out, cp, pub, ca, 0);
  				}
  				if (delete_host) {
  					if (!c && !ca)
  						printhost(out, cp, pub, ca, 0);
  					else
  						printf("# Host %s found: "
  						    "line %d type %s\n", name,
  						    num, key_type(pub));
  				}
  			} else if (hash_hosts)
  				printhost(out, cp, pub, ca, 0);
  		} else {
  			if (find_host || delete_host) {
  				c = (match_hostname(name, cp,
  				    strlen(cp)) == 1);
  				if (find_host && c) {
  					printf("# Host %s found: "
  					    "line %d type %s%s\n", name,
  					    num, key_type(pub),
  					    ca ? " (CA key)" : "");
  					printhost(out, name, pub,
  					    ca, hash_hosts && !ca);
  				}
  				if (delete_host) {
  					if (!c && !ca)
  						printhost(out, cp, pub, ca, 0);
  					else
  						printf("# Host %s found: "
  						    "line %d type %s\n", name,
  						    num, key_type(pub));
  				}
  			} else if (hash_hosts) {
  				for (cp2 = strsep(&cp, ",");
  				    cp2 != NULL && *cp2 != '\0';
  				    cp2 = strsep(&cp, ",")) {
  					if (ca) {
  						fprintf(stderr, "Warning: "
  						    "ignoring CA key for host: "
  						    "%.64s\n", cp2);
  						printhost(out, cp2, pub, ca, 0);
  					} else if (strcspn(cp2, "*?!") !=
  					    strlen(cp2)) {
  						fprintf(stderr, "Warning: "
  						    "ignoring host name with "
  						    "metacharacters: %.64s\n",
  						    cp2);
  						printhost(out, cp2, pub, ca, 0);
  					} else
  						printhost(out, cp2, pub, ca, 1);
  				}
  				has_unhashed = 1;
  			}
  		}
  		key_free(pub);
  	}
  	fclose(in);
  
  	if (invalid) {
  		fprintf(stderr, "%s is not a valid known_hosts file.\n",
  		    identity_file);
  		if (inplace) {
  			fprintf(stderr, "Not replacing existing known_hosts "
  			    "file because of errors\n");
  			fclose(out);
  			unlink(tmp);
  		}
  		exit(1);
  	}
  
  	if (inplace) {
  		fclose(out);
  
  		/* Backup existing file */
  		if (unlink(old) == -1 && errno != ENOENT)
  			fatal("unlink %.100s: %s", old, strerror(errno));
  		if (link(identity_file, old) == -1)
  			fatal("link %.100s to %.100s: %s", identity_file, old,
  			    strerror(errno));
  		/* Move new one into place */
  		if (rename(tmp, identity_file) == -1) {
  			error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
  			    strerror(errno));
  			unlink(tmp);
  			unlink(old);
  			exit(1);
  		}
  
  		fprintf(stderr, "%s updated.\n", identity_file);
  		fprintf(stderr, "Original contents retained as %s\n", old);
  		if (has_unhashed) {
  			fprintf(stderr, "WARNING: %s contains unhashed "
  			    "entries\n", old);
  			fprintf(stderr, "Delete this file to ensure privacy "
  			    "of hostnames\n");
  		}
  	}
  
  	exit(0);
  }
  
  /*
   * Perform changing a passphrase.  The argument is the passwd structure
   * for the current user.
   */
  static void
  do_change_passphrase(struct passwd *pw)
  {
  	char *comment;
  	char *old_passphrase, *passphrase1, *passphrase2;
  	struct stat st;
  	Key *private;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0) {
  		perror(identity_file);
  		exit(1);
  	}
  	/* Try to load the file with empty passphrase. */
  	private = key_load_private(identity_file, "", &comment);
  	if (private == NULL) {
  		if (identity_passphrase)
  			old_passphrase = xstrdup(identity_passphrase);
  		else
  			old_passphrase =
  			    read_passphrase("Enter old passphrase: ",
  			    RP_ALLOW_STDIN);
  		private = key_load_private(identity_file, old_passphrase,
  		    &comment);
  		memset(old_passphrase, 0, strlen(old_passphrase));
  		xfree(old_passphrase);
  		if (private == NULL) {
  			printf("Bad passphrase.\n");
  			exit(1);
  		}
  	}
  	printf("Key has comment '%s'\n", comment);
  
  	/* Ask the new passphrase (twice). */
  	if (identity_new_passphrase) {
  		passphrase1 = xstrdup(identity_new_passphrase);
  		passphrase2 = NULL;
  	} else {
  		passphrase1 =
  			read_passphrase("Enter new passphrase (empty for no "
  			    "passphrase): ", RP_ALLOW_STDIN);
  		passphrase2 = read_passphrase("Enter same passphrase again: ",
  		    RP_ALLOW_STDIN);
  
  		/* Verify that they are the same. */
  		if (strcmp(passphrase1, passphrase2) != 0) {
  			memset(passphrase1, 0, strlen(passphrase1));
  			memset(passphrase2, 0, strlen(passphrase2));
  			xfree(passphrase1);
  			xfree(passphrase2);
  			printf("Pass phrases do not match.  Try again.\n");
  			exit(1);
  		}
  		/* Destroy the other copy. */
  		memset(passphrase2, 0, strlen(passphrase2));
  		xfree(passphrase2);
  	}
  
  	/* Save the file using the new passphrase. */
  	if (!key_save_private(private, identity_file, passphrase1, comment)) {
  		printf("Saving the key failed: %s.\n", identity_file);
  		memset(passphrase1, 0, strlen(passphrase1));
  		xfree(passphrase1);
  		key_free(private);
  		xfree(comment);
  		exit(1);
  	}
  	/* Destroy the passphrase and the copy of the key in memory. */
  	memset(passphrase1, 0, strlen(passphrase1));
  	xfree(passphrase1);
  	key_free(private);		 /* Destroys contents */
  	xfree(comment);
  
  	printf("Your identification has been saved with the new passphrase.\n");
  	exit(0);
  }
  
  /*
   * Print the SSHFP RR.
   */
  static int
  do_print_resource_record(struct passwd *pw, char *fname, char *hname)
  {
  	Key *public;
  	char *comment = NULL;
  	struct stat st;
  
  	if (fname == NULL)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(fname, &st) < 0) {
  		if (errno == ENOENT)
  			return 0;
  		perror(fname);
  		exit(1);
  	}
  	public = key_load_public(fname, &comment);
  	if (public != NULL) {
  		export_dns_rr(hname, public, stdout, print_generic);
  		key_free(public);
  		xfree(comment);
  		return 1;
  	}
  	if (comment)
  		xfree(comment);
  
  	printf("failed to read v2 public key from %s.\n", fname);
  	exit(1);
  }
  
  /*
   * Change the comment of a private key file.
   */
  static void
  do_change_comment(struct passwd *pw)
  {
  	char new_comment[1024], *comment, *passphrase;
  	Key *private;
  	Key *public;
  	struct stat st;
  	FILE *f;
  	int fd;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0) {
  		perror(identity_file);
  		exit(1);
  	}
  	private = key_load_private(identity_file, "", &comment);
  	if (private == NULL) {
  		if (identity_passphrase)
  			passphrase = xstrdup(identity_passphrase);
  		else if (identity_new_passphrase)
  			passphrase = xstrdup(identity_new_passphrase);
  		else
  			passphrase = read_passphrase("Enter passphrase: ",
  			    RP_ALLOW_STDIN);
  		/* Try to load using the passphrase. */
  		private = key_load_private(identity_file, passphrase, &comment);
  		if (private == NULL) {
  			memset(passphrase, 0, strlen(passphrase));
  			xfree(passphrase);
  			printf("Bad passphrase.\n");
  			exit(1);
  		}
  	} else {
  		passphrase = xstrdup("");
  	}
  	if (private->type != KEY_RSA1) {
  		fprintf(stderr, "Comments are only supported for RSA1 keys.\n");
  		key_free(private);
  		exit(1);
  	}
  	printf("Key now has comment '%s'\n", comment);
  
  	if (identity_comment) {
  		strlcpy(new_comment, identity_comment, sizeof(new_comment));
  	} else {
  		printf("Enter new comment: ");
  		fflush(stdout);
  		if (!fgets(new_comment, sizeof(new_comment), stdin)) {
  			memset(passphrase, 0, strlen(passphrase));
  			key_free(private);
  			exit(1);
  		}
  		new_comment[strcspn(new_comment, "\n")] = '\0';
  	}
  
  	/* Save the file using the new passphrase. */
  	if (!key_save_private(private, identity_file, passphrase, new_comment)) {
  		printf("Saving the key failed: %s.\n", identity_file);
  		memset(passphrase, 0, strlen(passphrase));
  		xfree(passphrase);
  		key_free(private);
  		xfree(comment);
  		exit(1);
  	}
  	memset(passphrase, 0, strlen(passphrase));
  	xfree(passphrase);
  	public = key_from_private(private);
  	key_free(private);
  
  	strlcat(identity_file, ".pub", sizeof(identity_file));
  	fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
  	if (fd == -1) {
  		printf("Could not save your public key in %s\n", identity_file);
  		exit(1);
  	}
  	f = fdopen(fd, "w");
  	if (f == NULL) {
  		printf("fdopen %s failed\n", identity_file);
  		exit(1);
  	}
  	if (!key_write(public, f))
  		fprintf(stderr, "write key failed\n");
  	key_free(public);
  	fprintf(f, " %s\n", new_comment);
  	fclose(f);
  
  	xfree(comment);
  
  	printf("The comment in your key file has been changed.\n");
  	exit(0);
  }
  
  static const char *
  fmt_validity(u_int64_t valid_from, u_int64_t valid_to)
  {
  	char from[32], to[32];
  	static char ret[64];
  	time_t tt;
  	struct tm *tm;
  
  	*from = *to = '\0';
  	if (valid_from == 0 && valid_to == 0xffffffffffffffffULL)
  		return "forever";
  
  	if (valid_from != 0) {
  		/* XXX revisit INT_MAX in 2038 :) */
  		tt = valid_from > INT_MAX ? INT_MAX : valid_from;
  		tm = localtime(&tt);
  		strftime(from, sizeof(from), "%Y-%m-%dT%H:%M:%S", tm);
  	}
  	if (valid_to != 0xffffffffffffffffULL) {
  		/* XXX revisit INT_MAX in 2038 :) */
  		tt = valid_to > INT_MAX ? INT_MAX : valid_to;
  		tm = localtime(&tt);
  		strftime(to, sizeof(to), "%Y-%m-%dT%H:%M:%S", tm);
  	}
  
  	if (valid_from == 0) {
  		snprintf(ret, sizeof(ret), "before %s", to);
  		return ret;
  	}
  	if (valid_to == 0xffffffffffffffffULL) {
  		snprintf(ret, sizeof(ret), "after %s", from);
  		return ret;
  	}
  
  	snprintf(ret, sizeof(ret), "from %s to %s", from, to);
  	return ret;
  }
  
  static void
  add_flag_option(Buffer *c, const char *name)
  {
  	debug3("%s: %s", __func__, name);
  	buffer_put_cstring(c, name);
  	buffer_put_string(c, NULL, 0);
  }
  
  static void
  add_string_option(Buffer *c, const char *name, const char *value)
  {
  	Buffer b;
  
  	debug3("%s: %s=%s", __func__, name, value);
  	buffer_init(&b);
  	buffer_put_cstring(&b, value);
  
  	buffer_put_cstring(c, name);
  	buffer_put_string(c, buffer_ptr(&b), buffer_len(&b));
  
  	buffer_free(&b);
  }
  
  #define OPTIONS_CRITICAL	1
  #define OPTIONS_EXTENSIONS	2
  static void
  prepare_options_buf(Buffer *c, int which)
  {
  	buffer_clear(c);
  	if ((which & OPTIONS_CRITICAL) != 0 &&
  	    certflags_command != NULL)
  		add_string_option(c, "force-command", certflags_command);
  	if ((which & OPTIONS_EXTENSIONS) != 0 &&
  	    (certflags_flags & CERTOPT_X_FWD) != 0)
  		add_flag_option(c, "permit-X11-forwarding");
  	if ((which & OPTIONS_EXTENSIONS) != 0 &&
  	    (certflags_flags & CERTOPT_AGENT_FWD) != 0)
  		add_flag_option(c, "permit-agent-forwarding");
  	if ((which & OPTIONS_EXTENSIONS) != 0 &&
  	    (certflags_flags & CERTOPT_PORT_FWD) != 0)
  		add_flag_option(c, "permit-port-forwarding");
  	if ((which & OPTIONS_EXTENSIONS) != 0 &&
  	    (certflags_flags & CERTOPT_PTY) != 0)
  		add_flag_option(c, "permit-pty");
  	if ((which & OPTIONS_EXTENSIONS) != 0 &&
  	    (certflags_flags & CERTOPT_USER_RC) != 0)
  		add_flag_option(c, "permit-user-rc");
  	if ((which & OPTIONS_CRITICAL) != 0 &&
  	    certflags_src_addr != NULL)
  		add_string_option(c, "source-address", certflags_src_addr);
  }
  
  static Key *
  load_pkcs11_key(char *path)
  {
  #ifdef ENABLE_PKCS11
  	Key **keys = NULL, *public, *private = NULL;
  	int i, nkeys;
  
  	if ((public = key_load_public(path, NULL)) == NULL)
  		fatal("Couldn't load CA public key \"%s\"", path);
  
  	nkeys = pkcs11_add_provider(pkcs11provider, identity_passphrase, &keys);
  	debug3("%s: %d keys", __func__, nkeys);
  	if (nkeys <= 0)
  		fatal("cannot read public key from pkcs11");
  	for (i = 0; i < nkeys; i++) {
  		if (key_equal_public(public, keys[i])) {
  			private = keys[i];
  			continue;
  		}
  		key_free(keys[i]);
  	}
  	xfree(keys);
  	key_free(public);
  	return private;
  #else
  	fatal("no pkcs11 support");
  #endif /* ENABLE_PKCS11 */
  }
  
  static void
  do_ca_sign(struct passwd *pw, int argc, char **argv)
  {
  	int i, fd;
  	u_int n;
  	Key *ca, *public;
  	char *otmp, *tmp, *cp, *out, *comment, **plist = NULL;
  	FILE *f;
  	int v00 = 0; /* legacy keys */
  
  	if (key_type_name != NULL) {
  		switch (key_type_from_name(key_type_name)) {
  		case KEY_RSA_CERT_V00:
  		case KEY_DSA_CERT_V00:
  			v00 = 1;
  			break;
  		case KEY_UNSPEC:
  			if (strcasecmp(key_type_name, "v00") == 0) {
  				v00 = 1;
  				break;
  			} else if (strcasecmp(key_type_name, "v01") == 0)
  				break;
  			/* FALLTHROUGH */
  		default:
  			fprintf(stderr, "unknown key type %s\n", key_type_name);
  			exit(1);
  		}
  	}
  
  	pkcs11_init(1);
  	tmp = tilde_expand_filename(ca_key_path, pw->pw_uid);
  	if (pkcs11provider != NULL) {
  		if ((ca = load_pkcs11_key(tmp)) == NULL)
  			fatal("No PKCS#11 key matching %s found", ca_key_path);
  	} else if ((ca = load_identity(tmp)) == NULL)
  		fatal("Couldn't load CA key \"%s\"", tmp);
  	xfree(tmp);
  
  	for (i = 0; i < argc; i++) {
  		/* Split list of principals */
  		n = 0;
  		if (cert_principals != NULL) {
  			otmp = tmp = xstrdup(cert_principals);
  			plist = NULL;
  			for (; (cp = strsep(&tmp, ",")) != NULL; n++) {
  				plist = xrealloc(plist, n + 1, sizeof(*plist));
  				if (*(plist[n] = xstrdup(cp)) == '\0')
  					fatal("Empty principal name");
  			}
  			xfree(otmp);
  		}
  	
  		tmp = tilde_expand_filename(argv[i], pw->pw_uid);
  		if ((public = key_load_public(tmp, &comment)) == NULL)
  			fatal("%s: unable to open \"%s\"", __func__, tmp);
  		if (public->type != KEY_RSA && public->type != KEY_DSA &&
  		    public->type != KEY_ECDSA)
  			fatal("%s: key \"%s\" type %s cannot be certified",
  			    __func__, tmp, key_type(public));
  
  		/* Prepare certificate to sign */
  		if (key_to_certified(public, v00) != 0)
  			fatal("Could not upgrade key %s to certificate", tmp);
  		public->cert->type = cert_key_type;
  		public->cert->serial = (u_int64_t)cert_serial;
  		public->cert->key_id = xstrdup(cert_key_id);
  		public->cert->nprincipals = n;
  		public->cert->principals = plist;
  		public->cert->valid_after = cert_valid_from;
  		public->cert->valid_before = cert_valid_to;
  		if (v00) {
  			prepare_options_buf(&public->cert->critical,
  			    OPTIONS_CRITICAL|OPTIONS_EXTENSIONS);
  		} else {
  			prepare_options_buf(&public->cert->critical,
  			    OPTIONS_CRITICAL);
  			prepare_options_buf(&public->cert->extensions,
  			    OPTIONS_EXTENSIONS);
  		}
  		public->cert->signature_key = key_from_private(ca);
  
  		if (key_certify(public, ca) != 0)
  			fatal("Couldn't not certify key %s", tmp);
  
  		if ((cp = strrchr(tmp, '.')) != NULL && strcmp(cp, ".pub") == 0)
  			*cp = '\0';
  		xasprintf(&out, "%s-cert.pub", tmp);
  		xfree(tmp);
  
  		if ((fd = open(out, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
  			fatal("Could not open \"%s\" for writing: %s", out,
  			    strerror(errno));
  		if ((f = fdopen(fd, "w")) == NULL)
  			fatal("%s: fdopen: %s", __func__, strerror(errno));
  		if (!key_write(public, f))
  			fatal("Could not write certified key to %s", out);
  		fprintf(f, " %s\n", comment);
  		fclose(f);
  
  		if (!quiet) {
  			logit("Signed %s key %s: id \"%s\" serial %llu%s%s "
  			    "valid %s", key_cert_type(public), 
  			    out, public->cert->key_id,
  			    (unsigned long long)public->cert->serial,
  			    cert_principals != NULL ? " for " : "",
  			    cert_principals != NULL ? cert_principals : "",
  			    fmt_validity(cert_valid_from, cert_valid_to));
  		}
  
  		key_free(public);
  		xfree(out);
  	}
  	pkcs11_terminate();
  	exit(0);
  }
  
  static u_int64_t
  parse_relative_time(const char *s, time_t now)
  {
  	int64_t mul, secs;
  
  	mul = *s == '-' ? -1 : 1;
  
  	if ((secs = convtime(s + 1)) == -1)
  		fatal("Invalid relative certificate time %s", s);
  	if (mul == -1 && secs > now)
  		fatal("Certificate time %s cannot be represented", s);
  	return now + (u_int64_t)(secs * mul);
  }
  
  static u_int64_t
  parse_absolute_time(const char *s)
  {
  	struct tm tm;
  	time_t tt;
  	char buf[32], *fmt;
  
  	/*
  	 * POSIX strptime says "The application shall ensure that there 
  	 * is white-space or other non-alphanumeric characters between
  	 * any two conversion specifications" so arrange things this way.
  	 */
  	switch (strlen(s)) {
  	case 8:
  		fmt = "%Y-%m-%d";
  		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6);
  		break;
  	case 14:
  		fmt = "%Y-%m-%dT%H:%M:%S";
  		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s",
  		    s, s + 4, s + 6, s + 8, s + 10, s + 12);
  		break;
  	default:
  		fatal("Invalid certificate time format %s", s);
  	}
  
  	bzero(&tm, sizeof(tm));
  	if (strptime(buf, fmt, &tm) == NULL)
  		fatal("Invalid certificate time %s", s);
  	if ((tt = mktime(&tm)) < 0)
  		fatal("Certificate time %s cannot be represented", s);
  	return (u_int64_t)tt;
  }
  
  static void
  parse_cert_times(char *timespec)
  {
  	char *from, *to;
  	time_t now = time(NULL);
  	int64_t secs;
  
  	/* +timespec relative to now */
  	if (*timespec == '+' && strchr(timespec, ':') == NULL) {
  		if ((secs = convtime(timespec + 1)) == -1)
  			fatal("Invalid relative certificate life %s", timespec);
  		cert_valid_to = now + secs;
  		/*
  		 * Backdate certificate one minute to avoid problems on hosts
  		 * with poorly-synchronised clocks.
  		 */
  		cert_valid_from = ((now - 59)/ 60) * 60;
  		return;
  	}
  
  	/*
  	 * from:to, where
  	 * from := [+-]timespec | YYYYMMDD | YYYYMMDDHHMMSS
  	 *   to := [+-]timespec | YYYYMMDD | YYYYMMDDHHMMSS
  	 */
  	from = xstrdup(timespec);
  	to = strchr(from, ':');
  	if (to == NULL || from == to || *(to + 1) == '\0')
  		fatal("Invalid certificate life specification %s", timespec);
  	*to++ = '\0';
  
  	if (*from == '-' || *from == '+')
  		cert_valid_from = parse_relative_time(from, now);
  	else
  		cert_valid_from = parse_absolute_time(from);
  
  	if (*to == '-' || *to == '+')
  		cert_valid_to = parse_relative_time(to, cert_valid_from);
  	else
  		cert_valid_to = parse_absolute_time(to);
  
  	if (cert_valid_to <= cert_valid_from)
  		fatal("Empty certificate validity interval");
  	xfree(from);
  }
  
  static void
  add_cert_option(char *opt)
  {
  	char *val;
  
  	if (strcasecmp(opt, "clear") == 0)
  		certflags_flags = 0;
  	else if (strcasecmp(opt, "no-x11-forwarding") == 0)
  		certflags_flags &= ~CERTOPT_X_FWD;
  	else if (strcasecmp(opt, "permit-x11-forwarding") == 0)
  		certflags_flags |= CERTOPT_X_FWD;
  	else if (strcasecmp(opt, "no-agent-forwarding") == 0)
  		certflags_flags &= ~CERTOPT_AGENT_FWD;
  	else if (strcasecmp(opt, "permit-agent-forwarding") == 0)
  		certflags_flags |= CERTOPT_AGENT_FWD;
  	else if (strcasecmp(opt, "no-port-forwarding") == 0)
  		certflags_flags &= ~CERTOPT_PORT_FWD;
  	else if (strcasecmp(opt, "permit-port-forwarding") == 0)
  		certflags_flags |= CERTOPT_PORT_FWD;
  	else if (strcasecmp(opt, "no-pty") == 0)
  		certflags_flags &= ~CERTOPT_PTY;
  	else if (strcasecmp(opt, "permit-pty") == 0)
  		certflags_flags |= CERTOPT_PTY;
  	else if (strcasecmp(opt, "no-user-rc") == 0)
  		certflags_flags &= ~CERTOPT_USER_RC;
  	else if (strcasecmp(opt, "permit-user-rc") == 0)
  		certflags_flags |= CERTOPT_USER_RC;
  	else if (strncasecmp(opt, "force-command=", 14) == 0) {
  		val = opt + 14;
  		if (*val == '\0')
  			fatal("Empty force-command option");
  		if (certflags_command != NULL)
  			fatal("force-command already specified");
  		certflags_command = xstrdup(val);
  	} else if (strncasecmp(opt, "source-address=", 15) == 0) {
  		val = opt + 15;
  		if (*val == '\0')
  			fatal("Empty source-address option");
  		if (certflags_src_addr != NULL)
  			fatal("source-address already specified");
  		if (addr_match_cidr_list(NULL, val) != 0)
  			fatal("Invalid source-address list");
  		certflags_src_addr = xstrdup(val);
  	} else
  		fatal("Unsupported certificate option \"%s\"", opt);
  }
  
  static void
  show_options(const Buffer *optbuf, int v00, int in_critical)
  {
  	u_char *name, *data;
  	u_int dlen;
  	Buffer options, option;
  
  	buffer_init(&options);
  	buffer_append(&options, buffer_ptr(optbuf), buffer_len(optbuf));
  
  	buffer_init(&option);
  	while (buffer_len(&options) != 0) {
  		name = buffer_get_string(&options, NULL);
  		data = buffer_get_string_ptr(&options, &dlen);
  		buffer_append(&option, data, dlen);
  		printf("                %s", name);
  		if ((v00 || !in_critical) && 
  		    (strcmp(name, "permit-X11-forwarding") == 0 ||
  		    strcmp(name, "permit-agent-forwarding") == 0 ||
  		    strcmp(name, "permit-port-forwarding") == 0 ||
  		    strcmp(name, "permit-pty") == 0 ||
  		    strcmp(name, "permit-user-rc") == 0))
  			printf("\n");
  		else if ((v00 || in_critical) &&
  		    (strcmp(name, "force-command") == 0 ||
  		    strcmp(name, "source-address") == 0)) {
  			data = buffer_get_string(&option, NULL);
  			printf(" %s\n", data);
  			xfree(data);
  		} else {
  			printf(" UNKNOWN OPTION (len %u)\n",
  			    buffer_len(&option));
  			buffer_clear(&option);
  		}
  		xfree(name);
  		if (buffer_len(&option) != 0)
  			fatal("Option corrupt: extra data at end");
  	}
  	buffer_free(&option);
  	buffer_free(&options);
  }
  
  static void
  do_show_cert(struct passwd *pw)
  {
  	Key *key;
  	struct stat st;
  	char *key_fp, *ca_fp;
  	u_int i, v00;
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which the key is");
  	if (stat(identity_file, &st) < 0)
  		fatal("%s: %s: %s", __progname, identity_file, strerror(errno));
  	if ((key = key_load_public(identity_file, NULL)) == NULL)
  		fatal("%s is not a public key", identity_file);
  	if (!key_is_cert(key))
  		fatal("%s is not a certificate", identity_file);
  	v00 = key->type == KEY_RSA_CERT_V00 || key->type == KEY_DSA_CERT_V00;
  
  	key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
  	ca_fp = key_fingerprint(key->cert->signature_key,
  	    SSH_FP_MD5, SSH_FP_HEX);
  
  	printf("%s:\n", identity_file);
  	printf("        Type: %s %s certificate\n", key_ssh_name(key),
  	    key_cert_type(key));
  	printf("        Public key: %s %s\n", key_type(key), key_fp);
  	printf("        Signing CA: %s %s\n",
  	    key_type(key->cert->signature_key), ca_fp);
  	printf("        Key ID: \"%s\"\n", key->cert->key_id);
  	if (!v00) {
  		printf("        Serial: %llu\n",
  		    (unsigned long long)key->cert->serial);
  	}
  	printf("        Valid: %s\n",
  	    fmt_validity(key->cert->valid_after, key->cert->valid_before));
  	printf("        Principals: ");
  	if (key->cert->nprincipals == 0)
  		printf("(none)\n");
  	else {
  		for (i = 0; i < key->cert->nprincipals; i++)
  			printf("\n                %s",
  			    key->cert->principals[i]);
  		printf("\n");
  	}
  	printf("        Critical Options: ");
  	if (buffer_len(&key->cert->critical) == 0)
  		printf("(none)\n");
  	else {
  		printf("\n");
  		show_options(&key->cert->critical, v00, 1);
  	}
  	if (!v00) {
  		printf("        Extensions: ");
  		if (buffer_len(&key->cert->extensions) == 0)
  			printf("(none)\n");
  		else {
  			printf("\n");
  			show_options(&key->cert->extensions, v00, 0);
  		}
  	}
  	exit(0);
  }
  
  static void
  load_krl(const char *path, struct ssh_krl **krlp)
  {
  	Buffer krlbuf;
  	int fd;
  
  	buffer_init(&krlbuf);
  	if ((fd = open(path, O_RDONLY)) == -1)
  		fatal("open %s: %s", path, strerror(errno));
  	if (!key_load_file(fd, path, &krlbuf))
  		fatal("Unable to load KRL");
  	close(fd);
  	/* XXX check sigs */
  	if (ssh_krl_from_blob(&krlbuf, krlp, NULL, 0) != 0 ||
  	    *krlp == NULL)
  		fatal("Invalid KRL file");
  	buffer_free(&krlbuf);
  }
  
  static void
  update_krl_from_file(struct passwd *pw, const char *file, const Key *ca,
      struct ssh_krl *krl)
  {
  	Key *key = NULL;
  	u_long lnum = 0;
  	char *path, *cp, *ep, line[SSH_MAX_PUBKEY_BYTES];
  	unsigned long long serial, serial2;
  	int i, was_explicit_key, was_sha1, r;
  	FILE *krl_spec;
  
  	path = tilde_expand_filename(file, pw->pw_uid);
  	if (strcmp(path, "-") == 0) {
  		krl_spec = stdin;
  		free(path);
  		path = xstrdup("(standard input)");
  	} else if ((krl_spec = fopen(path, "r")) == NULL)
  		fatal("fopen %s: %s", path, strerror(errno));
  
  	if (!quiet)
  		printf("Revoking from %s\n", path);
  	while (read_keyfile_line(krl_spec, path, line, sizeof(line),
  	    &lnum) == 0) {
  		was_explicit_key = was_sha1 = 0;
  		cp = line + strspn(line, " \t");
  		/* Trim trailing space, comments and strip \n */
  		for (i = 0, r = -1; cp[i] != '\0'; i++) {
  			if (cp[i] == '#' || cp[i] == '\n') {
  				cp[i] = '\0';
  				break;
  			}
  			if (cp[i] == ' ' || cp[i] == '\t') {
  				/* Remember the start of a span of whitespace */
  				if (r == -1)
  					r = i;
  			} else
  				r = -1;
  		}
  		if (r != -1)
  			cp[r] = '\0';
  		if (*cp == '\0')
  			continue;
  		if (strncasecmp(cp, "serial:", 7) == 0) {
  			if (ca == NULL) {
  				fatal("revoking certificated by serial number "
  				    "requires specification of a CA key");
  			}
  			cp += 7;
  			cp = cp + strspn(cp, " \t");
  			errno = 0;
  			serial = strtoull(cp, &ep, 0);
  			if (*cp == '\0' || (*ep != '\0' && *ep != '-'))
  				fatal("%s:%lu: invalid serial \"%s\"",
  				    path, lnum, cp);
  			if (errno == ERANGE && serial == ULLONG_MAX)
  				fatal("%s:%lu: serial out of range",
  				    path, lnum);
  			serial2 = serial;
  			if (*ep == '-') {
  				cp = ep + 1;
  				errno = 0;
  				serial2 = strtoull(cp, &ep, 0);
  				if (*cp == '\0' || *ep != '\0')
  					fatal("%s:%lu: invalid serial \"%s\"",
  					    path, lnum, cp);
  				if (errno == ERANGE && serial2 == ULLONG_MAX)
  					fatal("%s:%lu: serial out of range",
  					    path, lnum);
  				if (serial2 <= serial)
  					fatal("%s:%lu: invalid serial range "
  					    "%llu:%llu", path, lnum,
  					    (unsigned long long)serial,
  					    (unsigned long long)serial2);
  			}
  			if (ssh_krl_revoke_cert_by_serial_range(krl,
  			    ca, serial, serial2) != 0) {
  				fatal("%s: revoke serial failed",
  				    __func__);
  			}
  		} else if (strncasecmp(cp, "id:", 3) == 0) {
  			if (ca == NULL) {
  				fatal("revoking certificated by key ID "
  				    "requires specification of a CA key");
  			}
  			cp += 3;
  			cp = cp + strspn(cp, " \t");
  			if (ssh_krl_revoke_cert_by_key_id(krl, ca, cp) != 0)
  				fatal("%s: revoke key ID failed", __func__);
  		} else {
  			if (strncasecmp(cp, "key:", 4) == 0) {
  				cp += 4;
  				cp = cp + strspn(cp, " \t");
  				was_explicit_key = 1;
  			} else if (strncasecmp(cp, "sha1:", 5) == 0) {
  				cp += 5;
  				cp = cp + strspn(cp, " \t");
  				was_sha1 = 1;
  			} else {
  				/*
  				 * Just try to process the line as a key.
  				 * Parsing will fail if it isn't.
  				 */
  			}
  			if ((key = key_new(KEY_UNSPEC)) == NULL)
  				fatal("key_new");
  			if (key_read(key, &cp) != 1)
  				fatal("%s:%lu: invalid key", path, lnum);
  			if (was_explicit_key)
  				r = ssh_krl_revoke_key_explicit(krl, key);
  			else if (was_sha1)
  				r = ssh_krl_revoke_key_sha1(krl, key);
  			else
  				r = ssh_krl_revoke_key(krl, key);
  			if (r != 0)
  				fatal("%s: revoke key failed", __func__);
  			key_free(key);
  		}
  	}
  	if (strcmp(path, "-") != 0)
  		fclose(krl_spec);
  }
  
  static void
  do_gen_krl(struct passwd *pw, int updating, int argc, char **argv)
  {
  	struct ssh_krl *krl;
  	struct stat sb;
  	Key *ca = NULL;
  	int fd, i;
  	char *tmp;
  	Buffer kbuf;
  
  	if (*identity_file == '\0')
  		fatal("KRL generation requires an output file");
  	if (stat(identity_file, &sb) == -1) {
  		if (errno != ENOENT)
  			fatal("Cannot access KRL \"%s\": %s",
  			    identity_file, strerror(errno));
  		if (updating)
  			fatal("KRL \"%s\" does not exist", identity_file);
  	}
  	if (ca_key_path != NULL) {
  		tmp = tilde_expand_filename(ca_key_path, pw->pw_uid);
  		if ((ca = key_load_public(tmp, NULL)) == NULL)
  			fatal("Cannot load CA public key %s", tmp);
  		xfree(tmp);
  	}
  
  	if (updating)
  		load_krl(identity_file, &krl);
  	else if ((krl = ssh_krl_init()) == NULL)
  		fatal("couldn't create KRL");
  
  	if (cert_serial != 0)
  		ssh_krl_set_version(krl, cert_serial);
  	if (identity_comment != NULL)
  		ssh_krl_set_comment(krl, identity_comment);
  
  	for (i = 0; i < argc; i++)
  		update_krl_from_file(pw, argv[i], ca, krl);
  
  	buffer_init(&kbuf);
  	if (ssh_krl_to_blob(krl, &kbuf, NULL, 0) != 0)
  		fatal("Couldn't generate KRL");
  	if ((fd = open(identity_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
  		fatal("open %s: %s", identity_file, strerror(errno));
  	if (atomicio(vwrite, fd, buffer_ptr(&kbuf), buffer_len(&kbuf)) !=
  	    buffer_len(&kbuf))
  		fatal("write %s: %s", identity_file, strerror(errno));
  	close(fd);
  	buffer_free(&kbuf);
  	ssh_krl_free(krl);
  }
  
  static void
  do_check_krl(struct passwd *pw, int argc, char **argv)
  {
  	int i, r, ret = 0;
  	char *comment;
  	struct ssh_krl *krl;
  	Key *k;
  
  	if (*identity_file == '\0')
  		fatal("KRL checking requires an input file");
  	load_krl(identity_file, &krl);
  	for (i = 0; i < argc; i++) {
  		if ((k = key_load_public(argv[i], &comment)) == NULL)
  			fatal("Cannot load public key %s", argv[i]);
  		r = ssh_krl_check_key(krl, k);
  		printf("%s%s%s%s: %s\n", argv[i],
  		    *comment ? " (" : "", comment, *comment ? ")" : "",
  		    r == 0 ? "ok" : "REVOKED");
  		if (r != 0)
  			ret = 1;
  		key_free(k);
  		free(comment);
  	}
  	ssh_krl_free(krl);
  	exit(ret);
  }
  
  static void
  usage(void)
  {
  	fprintf(stderr, "usage: %s [options]\n", __progname);
  	fprintf(stderr, "Options:\n");
  	fprintf(stderr, "  -A          Generate non-existent host keys for all key types.\n");
  	fprintf(stderr, "  -a trials   Number of trials for screening DH-GEX moduli.\n");
  	fprintf(stderr, "  -B          Show bubblebabble digest of key file.\n");
  	fprintf(stderr, "  -b bits     Number of bits in the key to create.\n");
  	fprintf(stderr, "  -C comment  Provide new comment.\n");
  	fprintf(stderr, "  -c          Change comment in private and public key files.\n");
  #ifdef ENABLE_PKCS11
  	fprintf(stderr, "  -D pkcs11   Download public key from pkcs11 token.\n");
  #endif
  	fprintf(stderr, "  -e          Export OpenSSH to foreign format key file.\n");
  	fprintf(stderr, "  -F hostname Find hostname in known hosts file.\n");
  	fprintf(stderr, "  -f filename Filename of the key file.\n");
  	fprintf(stderr, "  -G file     Generate candidates for DH-GEX moduli.\n");
  	fprintf(stderr, "  -g          Use generic DNS resource record format.\n");
  	fprintf(stderr, "  -H          Hash names in known_hosts file.\n");
  	fprintf(stderr, "  -h          Generate host certificate instead of a user certificate.\n");
  	fprintf(stderr, "  -I key_id   Key identifier to include in certificate.\n");
  	fprintf(stderr, "  -i          Import foreign format to OpenSSH key file.\n");
  	fprintf(stderr, "  -J number   Screen this number of moduli lines.\n");
  	fprintf(stderr, "  -j number   Start screening moduli at specified line.\n");
  	fprintf(stderr, "  -K checkpt  Write checkpoints to this file.\n");
  	fprintf(stderr, "  -k          Generate a KRL file.\n");
  	fprintf(stderr, "  -L          Print the contents of a certificate.\n");
  	fprintf(stderr, "  -l          Show fingerprint of key file.\n");
  	fprintf(stderr, "  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.\n");
  	fprintf(stderr, "  -m key_fmt  Conversion format for -e/-i (PEM|PKCS8|RFC4716).\n");
  	fprintf(stderr, "  -N phrase   Provide new passphrase.\n");
  	fprintf(stderr, "  -n name,... User/host principal names to include in certificate\n");
  	fprintf(stderr, "  -O option   Specify a certificate option.\n");
  	fprintf(stderr, "  -P phrase   Provide old passphrase.\n");
  	fprintf(stderr, "  -p          Change passphrase of private key file.\n");
  	fprintf(stderr, "  -Q          Test whether key(s) are revoked in KRL.\n");
  	fprintf(stderr, "  -q          Quiet.\n");
  	fprintf(stderr, "  -R hostname Remove host from known_hosts file.\n");
  	fprintf(stderr, "  -r hostname Print DNS resource record.\n");
  	fprintf(stderr, "  -S start    Start point (hex) for generating DH-GEX moduli.\n");
  	fprintf(stderr, "  -s ca_key   Certify keys with CA key.\n");
  	fprintf(stderr, "  -T file     Screen candidates for DH-GEX moduli.\n");
  	fprintf(stderr, "  -t type     Specify type of key to create.\n");
  	fprintf(stderr, "  -u          Update KRL rather than creating a new one.\n");
  	fprintf(stderr, "  -V from:to  Specify certificate validity interval.\n");
  	fprintf(stderr, "  -v          Verbose.\n");
  	fprintf(stderr, "  -W gen      Generator to use for generating DH-GEX moduli.\n");
  	fprintf(stderr, "  -y          Read private key file and print public key.\n");
  	fprintf(stderr, "  -z serial   Specify a serial number.\n");
  
  	exit(1);
  }
  
  /*
   * Main program for key management.
   */
  int
  main(int argc, char **argv)
  {
  	char dotsshdir[MAXPATHLEN], comment[1024], *passphrase1, *passphrase2;
  	char *checkpoint = NULL;
  	char out_file[MAXPATHLEN], *ep, *rr_hostname = NULL;
  	Key *private, *public;
  	struct passwd *pw;
  	struct stat st;
  	int opt, type, fd;
  	u_int32_t memory = 0, generator_wanted = 0, trials = 100;
  	int do_gen_candidates = 0, do_screen_candidates = 0;
  	int gen_all_hostkeys = 0, gen_krl = 0, update_krl = 0, check_krl = 0;
  	unsigned long start_lineno = 0, lines_to_process = 0;
  	BIGNUM *start = NULL;
  	FILE *f;
  	const char *errstr;
  
  	extern int optind;
  	extern char *optarg;
  
  	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
  	sanitise_stdfd();
  
  	__progname = ssh_get_progname(argv[0]);
  
  	OpenSSL_add_all_algorithms();
  	log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
  
  	seed_rng();
  
  	/* we need this for the home * directory.  */
  	pw = getpwuid(getuid());
  	if (!pw) {
  		printf("You don't exist, go away!\n");
  		exit(1);
  	}
  	if (gethostname(hostname, sizeof(hostname)) < 0) {
  		perror("gethostname");
  		exit(1);
  	}
  
  	while ((opt = getopt(argc, argv, "ABHLQXceghiklpquvxy"
  	    "C:D:F:G:I:J:K:M:N:O:P:R:S:T:V:W:a:b:f:g:j:m:n:r:s:t:z:")) != -1) {
  		switch (opt) {
  		case 'A':
  			gen_all_hostkeys = 1;
  			break;
  		case 'b':
  			bits = (u_int32_t)strtonum(optarg, 256, 32768, &errstr);
  			if (errstr)
  				fatal("Bits has bad value %s (%s)",
  					optarg, errstr);
  			break;
  		case 'F':
  			find_host = 1;
  			rr_hostname = optarg;
  			break;
  		case 'H':
  			hash_hosts = 1;
  			break;
  		case 'I':
  			cert_key_id = optarg;
  			break;
  		case 'J':
  			lines_to_process = strtoul(optarg, NULL, 10);
                          break;
  		case 'j':
  			start_lineno = strtoul(optarg, NULL, 10);
                          break;
  		case 'R':
  			delete_host = 1;
  			rr_hostname = optarg;
  			break;
  		case 'L':
  			show_cert = 1;
  			break;
  		case 'l':
  			print_fingerprint = 1;
  			break;
  		case 'B':
  			print_bubblebabble = 1;
  			break;
  		case 'm':
  			if (strcasecmp(optarg, "RFC4716") == 0 ||
  			    strcasecmp(optarg, "ssh2") == 0) {
  				convert_format = FMT_RFC4716;
  				break;
  			}
  			if (strcasecmp(optarg, "PKCS8") == 0) {
  				convert_format = FMT_PKCS8;
  				break;
  			}
  			if (strcasecmp(optarg, "PEM") == 0) {
  				convert_format = FMT_PEM;
  				break;
  			}
  			fatal("Unsupported conversion format \"%s\"", optarg);
  		case 'n':
  			cert_principals = optarg;
  			break;
  		case 'p':
  			change_passphrase = 1;
  			break;
  		case 'c':
  			change_comment = 1;
  			break;
  		case 'f':
  			if (strlcpy(identity_file, optarg, sizeof(identity_file)) >=
  			    sizeof(identity_file))
  				fatal("Identity filename too long");
  			have_identity = 1;
  			break;
  		case 'g':
  			print_generic = 1;
  			break;
  		case 'P':
  			identity_passphrase = optarg;
  			break;
  		case 'N':
  			identity_new_passphrase = optarg;
  			break;
  		case 'Q':
  			check_krl = 1;
  			break;
  		case 'O':
  			add_cert_option(optarg);
  			break;
  		case 'C':
  			identity_comment = optarg;
  			break;
  		case 'q':
  			quiet = 1;
  			break;
  		case 'e':
  		case 'x':
  			/* export key */
  			convert_to = 1;
  			break;
  		case 'h':
  			cert_key_type = SSH2_CERT_TYPE_HOST;
  			certflags_flags = 0;
  			break;
  		case 'k':
  			gen_krl = 1;
  			break;
  		case 'i':
  		case 'X':
  			/* import key */
  			convert_from = 1;
  			break;
  		case 'y':
  			print_public = 1;
  			break;
  		case 's':
  			ca_key_path = optarg;
  			break;
  		case 't':
  			key_type_name = optarg;
  			break;
  		case 'D':
  			pkcs11provider = optarg;
  			break;
  		case 'u':
  			update_krl = 1;
  			break;
  		case 'v':
  			if (log_level == SYSLOG_LEVEL_INFO)
  				log_level = SYSLOG_LEVEL_DEBUG1;
  			else {
  				if (log_level >= SYSLOG_LEVEL_DEBUG1 &&
  				    log_level < SYSLOG_LEVEL_DEBUG3)
  					log_level++;
  			}
  			break;
  		case 'r':
  			rr_hostname = optarg;
  			break;
  		case 'W':
  			generator_wanted = (u_int32_t)strtonum(optarg, 1,
  			    UINT_MAX, &errstr);
  			if (errstr)
  				fatal("Desired generator has bad value: %s (%s)",
  					optarg, errstr);
  			break;
  		case 'a':
  			trials = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
  			if (errstr)
  				fatal("Invalid number of trials: %s (%s)",
  					optarg, errstr);
  			break;
  		case 'M':
  			memory = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
  			if (errstr)
  				fatal("Memory limit is %s: %s", errstr, optarg);
  			break;
  		case 'G':
  			do_gen_candidates = 1;
  			if (strlcpy(out_file, optarg, sizeof(out_file)) >=
  			    sizeof(out_file))
  				fatal("Output filename too long");
  			break;
  		case 'T':
  			do_screen_candidates = 1;
  			if (strlcpy(out_file, optarg, sizeof(out_file)) >=
  			    sizeof(out_file))
  				fatal("Output filename too long");
  			break;
  		case 'K':
  			if (strlen(optarg) >= MAXPATHLEN)
  				fatal("Checkpoint filename too long");
  			checkpoint = xstrdup(optarg);
  			break;
  		case 'S':
  			/* XXX - also compare length against bits */
  			if (BN_hex2bn(&start, optarg) == 0)
  				fatal("Invalid start point.");
  			break;
  		case 'V':
  			parse_cert_times(optarg);
  			break;
  		case 'z':
  			errno = 0;
  			cert_serial = strtoull(optarg, &ep, 10);
  			if (*optarg < '0' || *optarg > '9' || *ep != '\0' ||
  			    (errno == ERANGE && cert_serial == ULLONG_MAX))
  				fatal("Invalid serial number \"%s\"", optarg);
  			break;
  		case '?':
  		default:
  			usage();
  		}
  	}
  
  	/* reinit */
  	log_init(argv[0], log_level, SYSLOG_FACILITY_USER, 1);
  
  	argv += optind;
  	argc -= optind;
  
  	if (ca_key_path != NULL) {
  		if (argc < 1 && !gen_krl) {
  			printf("Too few arguments.\n");
  			usage();
  		}
  	} else if (argc > 0 && !gen_krl && !check_krl) {
  		printf("Too many arguments.\n");
  		usage();
  	}
  	if (change_passphrase && change_comment) {
  		printf("Can only have one of -p and -c.\n");
  		usage();
  	}
  	if (print_fingerprint && (delete_host || hash_hosts)) {
  		printf("Cannot use -l with -H or -R.\n");
  		usage();
  	}
  	if (gen_krl) {
  		do_gen_krl(pw, update_krl, argc, argv);
  		return (0);
  	}
  	if (check_krl) {
  		do_check_krl(pw, argc, argv);
  		return (0);
  	}
  	if (ca_key_path != NULL) {
  		if (cert_key_id == NULL)
  			fatal("Must specify key id (-I) when certifying");
  		do_ca_sign(pw, argc, argv);
  	}
  	if (show_cert)
  		do_show_cert(pw);
  	if (delete_host || hash_hosts || find_host)
  		do_known_hosts(pw, rr_hostname);
  	if (pkcs11provider != NULL)
  		do_download(pw);
  	if (print_fingerprint || print_bubblebabble)
  		do_fingerprint(pw);
  	if (change_passphrase)
  		do_change_passphrase(pw);
  	if (change_comment)
  		do_change_comment(pw);
  	if (convert_to)
  		do_convert_to(pw);
  	if (convert_from)
  		do_convert_from(pw);
  	if (print_public)
  		do_print_public(pw);
  	if (rr_hostname != NULL) {
  		unsigned int n = 0;
  
  		if (have_identity) {
  			n = do_print_resource_record(pw,
  			    identity_file, rr_hostname);
  			if (n == 0) {
  				perror(identity_file);
  				exit(1);
  			}
  			exit(0);
  		} else {
  
  			n += do_print_resource_record(pw,
  			    _PATH_HOST_RSA_KEY_FILE, rr_hostname);
  			n += do_print_resource_record(pw,
  			    _PATH_HOST_DSA_KEY_FILE, rr_hostname);
  			n += do_print_resource_record(pw,
  			    _PATH_HOST_ECDSA_KEY_FILE, rr_hostname);
  
  			if (n == 0)
  				fatal("no keys found.");
  			exit(0);
  		}
  	}
  
  	if (do_gen_candidates) {
  		FILE *out = fopen(out_file, "w");
  
  		if (out == NULL) {
  			error("Couldn't open modulus candidate file \"%s\": %s",
  			    out_file, strerror(errno));
  			return (1);
  		}
  		if (bits == 0)
  			bits = DEFAULT_BITS;
  		if (gen_candidates(out, memory, bits, start) != 0)
  			fatal("modulus candidate generation failed");
  
  		return (0);
  	}
  
  	if (do_screen_candidates) {
  		FILE *in;
  		FILE *out = fopen(out_file, "a");
  
  		if (have_identity && strcmp(identity_file, "-") != 0) {
  			if ((in = fopen(identity_file, "r")) == NULL) {
  				fatal("Couldn't open modulus candidate "
  				    "file \"%s\": %s", identity_file,
  				    strerror(errno));
  			}
  		} else
  			in = stdin;
  
  		if (out == NULL) {
  			fatal("Couldn't open moduli file \"%s\": %s",
  			    out_file, strerror(errno));
  		}
  		if (prime_test(in, out, trials, generator_wanted, checkpoint,
  		    start_lineno, lines_to_process) != 0)
  			fatal("modulus screening failed");
  		return (0);
  	}
  
  	if (gen_all_hostkeys) {
  		do_gen_all_hostkeys(pw);
  		return (0);
  	}
  
  	arc4random_stir();
  
  	if (key_type_name == NULL)
  		key_type_name = "rsa";
  
  	type = key_type_from_name(key_type_name);
  	type_bits_valid(type, &bits);
  
  	if (!quiet)
  		printf("Generating public/private %s key pair.\n", key_type_name);
  	private = key_generate(type, bits);
  	if (private == NULL) {
  		fprintf(stderr, "key_generate failed\n");
  		exit(1);
  	}
  	public  = key_from_private(private);
  
  	if (!have_identity)
  		ask_filename(pw, "Enter file in which to save the key");
  
  	/* Create ~/.ssh directory if it doesn't already exist. */
  	snprintf(dotsshdir, sizeof dotsshdir, "%s/%s",
  	    pw->pw_dir, _PATH_SSH_USER_DIR);
  	if (strstr(identity_file, dotsshdir) != NULL) {
  		if (stat(dotsshdir, &st) < 0) {
  			if (errno != ENOENT) {
  				error("Could not stat %s: %s", dotsshdir,
  				    strerror(errno));
  			} else if (mkdir(dotsshdir, 0700) < 0) {
  				error("Could not create directory '%s': %s",
  				    dotsshdir, strerror(errno));
  			} else if (!quiet)
  				printf("Created directory '%s'.\n", dotsshdir);
  		}
  	}
  	/* If the file already exists, ask the user to confirm. */
  	if (stat(identity_file, &st) >= 0) {
  		char yesno[3];
  		printf("%s already exists.\n", identity_file);
  		printf("Overwrite (y/n)? ");
  		fflush(stdout);
  		if (fgets(yesno, sizeof(yesno), stdin) == NULL)
  			exit(1);
  		if (yesno[0] != 'y' && yesno[0] != 'Y')
  			exit(1);
  	}
  	/* Ask for a passphrase (twice). */
  	if (identity_passphrase)
  		passphrase1 = xstrdup(identity_passphrase);
  	else if (identity_new_passphrase)
  		passphrase1 = xstrdup(identity_new_passphrase);
  	else {
  passphrase_again:
  		passphrase1 =
  			read_passphrase("Enter passphrase (empty for no "
  			    "passphrase): ", RP_ALLOW_STDIN);
  		passphrase2 = read_passphrase("Enter same passphrase again: ",
  		    RP_ALLOW_STDIN);
  		if (strcmp(passphrase1, passphrase2) != 0) {
  			/*
  			 * The passphrases do not match.  Clear them and
  			 * retry.
  			 */
  			memset(passphrase1, 0, strlen(passphrase1));
  			memset(passphrase2, 0, strlen(passphrase2));
  			xfree(passphrase1);
  			xfree(passphrase2);
  			printf("Passphrases do not match.  Try again.\n");
  			goto passphrase_again;
  		}
  		/* Clear the other copy of the passphrase. */
  		memset(passphrase2, 0, strlen(passphrase2));
  		xfree(passphrase2);
  	}
  
  	if (identity_comment) {
  		strlcpy(comment, identity_comment, sizeof(comment));
  	} else {
  		/* Create default comment field for the passphrase. */
  		snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
  	}
  
  	/* Save the key with the given passphrase and comment. */
  	if (!key_save_private(private, identity_file, passphrase1, comment)) {
  		printf("Saving the key failed: %s.\n", identity_file);
  		memset(passphrase1, 0, strlen(passphrase1));
  		xfree(passphrase1);
  		exit(1);
  	}
  	/* Clear the passphrase. */
  	memset(passphrase1, 0, strlen(passphrase1));
  	xfree(passphrase1);
  
  	/* Clear the private key and the random number generator. */
  	key_free(private);
  	arc4random_stir();
  
  	if (!quiet)
  		printf("Your identification has been saved in %s.\n", identity_file);
  
  	strlcat(identity_file, ".pub", sizeof(identity_file));
  	fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
  	if (fd == -1) {
  		printf("Could not save your public key in %s\n", identity_file);
  		exit(1);
  	}
  	f = fdopen(fd, "w");
  	if (f == NULL) {
  		printf("fdopen %s failed\n", identity_file);
  		exit(1);
  	}
  	if (!key_write(public, f))
  		fprintf(stderr, "write key failed\n");
  	fprintf(f, " %s\n", comment);
  	fclose(f);
  
  	if (!quiet) {
  		char *fp = key_fingerprint(public, SSH_FP_MD5, SSH_FP_HEX);
  		char *ra = key_fingerprint(public, SSH_FP_MD5,
  		    SSH_FP_RANDOMART);
  		printf("Your public key has been saved in %s.\n",
  		    identity_file);
  		printf("The key fingerprint is:\n");
  		printf("%s %s\n", fp, comment);
  		printf("The key's randomart image is:\n");
  		printf("%s\n", ra);
  		xfree(ra);
  		xfree(fp);
  	}
  
  	key_free(public);
  	exit(0);
  }
  