usr.bin/ssh/ssh-keygen.c

/* $OpenBSD: ssh-keygen.c,v 1.271 2015/04/27 01:52:30 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 <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <openssl/evp.h>
#include <openssl/pem.h>

#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

#include "xmalloc.h"
#include "sshkey.h"
#include "rsa.h"
#include "authfile.h"
#include "uuencode.h"
#include "sshbuf.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 "ssherr.h"
#include "atomicio.h"
#include "krl.h"
#include "digest.h"

#ifdef ENABLE_PKCS11
#include "ssh-pkcs11.h"
#endif

/* 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;

/* Hash algorithm to use for fingerprints. */
int fingerprint_hash = SSH_FP_HASH_DEFAULT;

/* 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;

/* Use new OpenSSH private key format when writing SSH2 keys instead of PEM */
int use_new_format = 0;

/* Cipher for new-format private keys */
char *new_format_cipher = NULL;

/*
 * Number of KDF rounds to derive new format keys /
 * number of primality trials when screening moduli.
 */
int rounds = 0;

/* argv0 */
extern char *__progname;

char hostname[NI_MAXHOST];

/* 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, const char *name, u_int32_t *bitsp)
{
#ifdef WITH_OPENSSL
	u_int maxbits, nid;
#endif

	if (type == KEY_UNSPEC)
		fatal("unknown key type %s", key_type_name);
	if (*bitsp == 0) {
#ifdef WITH_OPENSSL
		if (type == KEY_DSA)
			*bitsp = DEFAULT_BITS_DSA;
		else if (type == KEY_ECDSA) {
			if (name != NULL &&
			    (nid = sshkey_ecdsa_nid_from_name(name)) > 0)
				*bitsp = sshkey_curve_nid_to_bits(nid);
			if (*bitsp == 0)
				*bitsp = DEFAULT_BITS_ECDSA;
		}
		else
#endif
			*bitsp = DEFAULT_BITS;
	}
#ifdef WITH_OPENSSL
	maxbits = (type == KEY_DSA) ?
	    OPENSSL_DSA_MAX_MODULUS_BITS : OPENSSL_RSA_MAX_MODULUS_BITS;
	if (*bitsp > maxbits)
		fatal("key bits exceeds maximum %d", maxbits);
	if (type == KEY_DSA && *bitsp != 1024)
		fatal("DSA keys must be 1024 bits");
	else if (type != KEY_ECDSA && type != KEY_ED25519 && *bitsp < 768)
		fatal("Key must at least be 768 bits");
	else if (type == KEY_ECDSA && sshkey_ecdsa_bits_to_nid(*bitsp) == -1)
		fatal("Invalid ECDSA key length - valid lengths are "
		    "256, 384 or 521 bits");
#endif
}

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 (sshkey_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;
		case KEY_ECDSA_CERT:
		case KEY_ECDSA:
			name = _PATH_SSH_CLIENT_ID_ECDSA;
			break;
		case KEY_RSA_CERT:
		case KEY_RSA_CERT_V00:
		case KEY_RSA:
			name = _PATH_SSH_CLIENT_ID_RSA;
			break;
		case KEY_ED25519:
		case KEY_ED25519_CERT:
			name = _PATH_SSH_CLIENT_ID_ED25519;
			break;
		default:
			fatal("bad key type");
		}
	}
	snprintf(identity_file, sizeof(identity_file),
	    "%s/%s", pw->pw_dir, name);
	printf("%s (%s): ", prompt, identity_file);
	fflush(stdout);
	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 struct sshkey *
load_identity(char *filename)
{
	char *pass;
	struct sshkey *prv;
	int r;

	if ((r = sshkey_load_private(filename, "", &prv, NULL)) == 0)
		return prv;
	if (r != SSH_ERR_KEY_WRONG_PASSPHRASE)
		fatal("Load key \"%s\": %s", filename, ssh_err(r));
	if (identity_passphrase)
		pass = xstrdup(identity_passphrase);
	else
		pass = read_passphrase("Enter passphrase: ", RP_ALLOW_STDIN);
	r = sshkey_load_private(filename, pass, &prv, NULL);
	explicit_bzero(pass, strlen(pass));
	free(pass);
	if (r != 0)
		fatal("Load key \"%s\": %s", filename, ssh_err(r));
	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

#ifdef WITH_OPENSSL
static void
do_convert_to_ssh2(struct passwd *pw, struct sshkey *k)
{
	size_t len;
	u_char *blob;
	char comment[61];
	int r;

	if (k->type == KEY_RSA1)
		fatal("version 1 keys are not supported");
	if ((r = sshkey_to_blob(k, &blob, &len)) != 0)
		fatal("key_to_blob failed: %s", ssh_err(r));
	/* 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",
	    sshkey_size(k), sshkey_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);
	sshkey_free(k);
	free(blob);
	exit(0);
}

static void
do_convert_to_pkcs8(struct sshkey *k)
{
	switch (sshkey_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;
	case KEY_ECDSA:
		if (!PEM_write_EC_PUBKEY(stdout, k->ecdsa))
			fatal("PEM_write_EC_PUBKEY failed");
		break;
	default:
		fatal("%s: unsupported key type %s", __func__, sshkey_type(k));
	}
	exit(0);
}

static void
do_convert_to_pem(struct sshkey *k)
{
	switch (sshkey_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__, sshkey_type(k));
	}
	exit(0);
}

static void
do_convert_to(struct passwd *pw)
{
	struct sshkey *k;
	struct stat st;
	int r;

	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 ((r = sshkey_load_public(identity_file, &k, NULL)) != 0)
		k = load_identity(identity_file);
	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);
}

/*
 * This is almost exactly the bignum1 encoding, but with 32 bit for length
 * instead of 16.
 */
static void
buffer_get_bignum_bits(struct sshbuf *b, BIGNUM *value)
{
	u_int bytes, bignum_bits;
	int r;

	if ((r = sshbuf_get_u32(b, &bignum_bits)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));
	bytes = (bignum_bits + 7) / 8;
	if (sshbuf_len(b) < bytes)
		fatal("%s: input buffer too small: need %d have %zu",
		    __func__, bytes, sshbuf_len(b));
	if (BN_bin2bn(sshbuf_ptr(b), bytes, value) == NULL)
		fatal("%s: BN_bin2bn failed", __func__);
	if ((r = sshbuf_consume(b, bytes)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));
}

static struct sshkey *
do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
{
	struct sshbuf *b;
	struct sshkey *key = NULL;
	char *type, *cipher;
	u_char e1, e2, e3, *sig = NULL, data[] = "abcde12345";
	int r, rlen, ktype;
	u_int magic, i1, i2, i3, i4;
	size_t slen;
	u_long e;

	if ((b = sshbuf_from(blob, blen)) == NULL)
		fatal("%s: sshbuf_from failed", __func__);
	if ((r = sshbuf_get_u32(b, &magic)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));

	if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
		error("bad magic 0x%x != 0x%x", magic,
		    SSH_COM_PRIVATE_KEY_MAGIC);
		sshbuf_free(b);
		return NULL;
	}
	if ((r = sshbuf_get_u32(b, &i1)) != 0 ||
	    (r = sshbuf_get_cstring(b, &type, NULL)) != 0 ||
	    (r = sshbuf_get_cstring(b, &cipher, NULL)) != 0 ||
	    (r = sshbuf_get_u32(b, &i2)) != 0 ||
	    (r = sshbuf_get_u32(b, &i3)) != 0 ||
	    (r = sshbuf_get_u32(b, &i4)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));
	debug("ignore (%d %d %d %d)", i1, i2, i3, i4);
	if (strcmp(cipher, "none") != 0) {
		error("unsupported cipher %s", cipher);
		free(cipher);
		sshbuf_free(b);
		free(type);
		return NULL;
	}
	free(cipher);

	if (strstr(type, "dsa")) {
		ktype = KEY_DSA;
	} else if (strstr(type, "rsa")) {
		ktype = KEY_RSA;
	} else {
		sshbuf_free(b);
		free(type);
		return NULL;
	}
	if ((key = sshkey_new_private(ktype)) == NULL)
		fatal("key_new_private failed");
	free(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:
		if ((r = sshbuf_get_u8(b, &e1)) != 0 ||
		    (e1 < 30 && (r = sshbuf_get_u8(b, &e2)) != 0) ||
		    (e1 < 30 && (r = sshbuf_get_u8(b, &e3)) != 0))
			fatal("%s: buffer error: %s", __func__, ssh_err(r));
		e = e1;
		debug("e %lx", e);
		if (e < 30) {
			e <<= 8;
			e += e2;
			debug("e %lx", e);
			e <<= 8;
			e += e3;
			debug("e %lx", e);
		}
		if (!BN_set_word(key->rsa->e, e)) {
			sshbuf_free(b);
			sshkey_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);
		if ((r = rsa_generate_additional_parameters(key->rsa)) != 0)
			fatal("generate RSA parameters failed: %s", ssh_err(r));
		break;
	}
	rlen = sshbuf_len(b);
	if (rlen != 0)
		error("do_convert_private_ssh2_from_blob: "
		    "remaining bytes in key blob %d", rlen);
	sshbuf_free(b);

	/* try the key */
	if (sshkey_sign(key, &sig, &slen, data, sizeof(data), 0) != 0 ||
	    sshkey_verify(key, sig, slen, data, sizeof(data), 0) != 0) {
		sshkey_free(key);
		free(sig);
		return NULL;
	}
	free(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)
			fatal("input line too long.");
		switch (c) {
		case '\r':
			c = fgetc(fp);
			if (c != EOF && c != '\n' && ungetc(c, fp) == EOF)
				fatal("unget: %s", strerror(errno));
			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, struct sshkey **k, int *private)
{
	int r, blen, escaped = 0;
	u_int len;
	char line[1024];
	u_char blob[8096];
	char encoded[8096];
	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 (blen > 0 && 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)
		fatal("uudecode failed.");
	if (*private)
		*k = do_convert_private_ssh2_from_blob(blob, blen);
	else if ((r = sshkey_from_blob(blob, blen, k)) != 0)
		fatal("decode blob failed: %s", ssh_err(r));
	fclose(fp);
}

static void
do_convert_from_pkcs8(struct sshkey **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:
		if ((*k = sshkey_new(KEY_UNSPEC)) == NULL)
			fatal("sshkey_new failed");
		(*k)->type = KEY_RSA;
		(*k)->rsa = EVP_PKEY_get1_RSA(pubkey);
		break;
	case EVP_PKEY_DSA:
		if ((*k = sshkey_new(KEY_UNSPEC)) == NULL)
			fatal("sshkey_new failed");
		(*k)->type = KEY_DSA;
		(*k)->dsa = EVP_PKEY_get1_DSA(pubkey);
		break;
	case EVP_PKEY_EC:
		if ((*k = sshkey_new(KEY_UNSPEC)) == NULL)
			fatal("sshkey_new failed");
		(*k)->type = KEY_ECDSA;
		(*k)->ecdsa = EVP_PKEY_get1_EC_KEY(pubkey);
		(*k)->ecdsa_nid = sshkey_ecdsa_key_to_nid((*k)->ecdsa);
		break;
	default:
		fatal("%s: unsupported pubkey type %d", __func__,
		    EVP_PKEY_type(pubkey->type));
	}
	EVP_PKEY_free(pubkey);
	return;
}

static void
do_convert_from_pem(struct sshkey **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) {
		if ((*k = sshkey_new(KEY_UNSPEC)) == NULL)
			fatal("sshkey_new failed");
		(*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) {
		if ((*k = sshkey_new(KEY_UNSPEC)) == NULL)
			fatal("sshkey_new failed");
		(*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)
{
	struct sshkey *k = NULL;
	int r, 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) {
		if ((r = sshkey_write(k, stdout)) == 0)
			ok = 1;
		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;
		case KEY_ECDSA:
			ok = PEM_write_ECPrivateKey(stdout, k->ecdsa, NULL,
			    NULL, 0, NULL, NULL);
			break;
		case KEY_RSA:
			ok = PEM_write_RSAPrivateKey(stdout, k->rsa, NULL,
			    NULL, 0, NULL, NULL);
			break;
		default:
			fatal("%s: unsupported key type %s", __func__,
			    sshkey_type(k));
		}
	}

	if (!ok)
		fatal("key write failed");
	sshkey_free(k);
	exit(0);
}
#endif

static void
do_print_public(struct passwd *pw)
{
	struct sshkey *prv;
	struct stat st;
	int r;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0)
		fatal("%s: %s", identity_file, strerror(errno));
	prv = load_identity(identity_file);
	if ((r = sshkey_write(prv, stdout)) != 0)
		error("key_write failed: %s", ssh_err(r));
	sshkey_free(prv);
	fprintf(stdout, "\n");
	exit(0);
}

static void
do_download(struct passwd *pw)
{
#ifdef ENABLE_PKCS11
	struct sshkey **keys = NULL;
	int i, nkeys;
	enum sshkey_fp_rep rep;
	int fptype;
	char *fp, *ra;

	fptype = print_bubblebabble ? SSH_DIGEST_SHA1 : fingerprint_hash;
	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_DEFAULT;

	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 = sshkey_fingerprint(keys[i], fptype, rep);
			ra = sshkey_fingerprint(keys[i], fingerprint_hash,
			    SSH_FP_RANDOMART);
			if (fp == NULL || ra == NULL)
				fatal("%s: sshkey_fingerprint fail", __func__);
			printf("%u %s %s (PKCS11 key)\n", sshkey_size(keys[i]),
			    fp, sshkey_type(keys[i]));
			if (log_level >= SYSLOG_LEVEL_VERBOSE)
				printf("%s\n", ra);
			free(ra);
			free(fp);
		} else {
			(void) sshkey_write(keys[i], stdout); /* XXX check */
			fprintf(stdout, "\n");
		}
		sshkey_free(keys[i]);
	}
	free(keys);
	pkcs11_terminate();
	exit(0);
#else
	fatal("no pkcs11 support");
#endif /* ENABLE_PKCS11 */
}

static void
do_fingerprint(struct passwd *pw)
{
	FILE *f;
	struct sshkey *public;
	char *comment = NULL, *cp, *ep, line[16*1024], *fp, *ra;
	int r, i, skip = 0, num = 0, invalid = 1;
	enum sshkey_fp_rep rep;
	int fptype;
	struct stat st;

	fptype = print_bubblebabble ? SSH_DIGEST_SHA1 : fingerprint_hash;
	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_DEFAULT;
	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0)
		fatal("%s: %s", identity_file, strerror(errno));
	if ((r = sshkey_load_public(identity_file, &public, &comment)) != 0)
		debug2("Error loading public key \"%s\": %s",
		    identity_file, ssh_err(r));
	else {
		fp = sshkey_fingerprint(public, fptype, rep);
		ra = sshkey_fingerprint(public, fingerprint_hash,
		    SSH_FP_RANDOMART);
		if (fp == NULL || ra == NULL)
			fatal("%s: sshkey_fingerprint fail", __func__);
		printf("%u %s %s (%s)\n", sshkey_size(public), fp, comment,
		    sshkey_type(public));
		if (log_level >= SYSLOG_LEVEL_VERBOSE)
			printf("%s\n", ra);
		sshkey_free(public);
		free(comment);
		free(ra);
		free(fp);
		exit(0);
	}
	if (comment) {
		free(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;
		if ((public = sshkey_new(KEY_RSA1)) == NULL)
			fatal("sshkey_new failed");
		if ((r = sshkey_read(public, &cp)) != 0) {
			cp = ep;
			sshkey_free(public);
			if ((public = sshkey_new(KEY_UNSPEC)) == NULL)
				fatal("sshkey_new failed");
			if ((r = sshkey_read(public, &cp)) != 0) {
				sshkey_free(public);
				continue;
			}
		}
		comment = *cp ? cp : comment;
		fp = sshkey_fingerprint(public, fptype, rep);
		ra = sshkey_fingerprint(public, fingerprint_hash,
		    SSH_FP_RANDOMART);
		if (fp == NULL || ra == NULL)
			fatal("%s: sshkey_fingerprint fail", __func__);
		printf("%u %s %s (%s)\n", sshkey_size(public), fp,
		    comment ? comment : "no comment", sshkey_type(public));
		if (log_level >= SYSLOG_LEVEL_VERBOSE)
			printf("%s\n", ra);
		free(ra);
		free(fp);
		sshkey_free(public);
		invalid = 0;
	}
	fclose(f);

	if (invalid)
		fatal("%s is not a public key file.", identity_file);
	exit(0);
}

static void
do_gen_all_hostkeys(struct passwd *pw)
{
	struct {
		char *key_type;
		char *key_type_display;
		char *path;
	} key_types[] = {
#ifdef WITH_OPENSSL
#ifdef WITH_SSH1
		{ "rsa1", "RSA1", _PATH_HOST_KEY_FILE },
#endif /* WITH_SSH1 */
		{ "rsa", "RSA" ,_PATH_HOST_RSA_KEY_FILE },
		{ "dsa", "DSA", _PATH_HOST_DSA_KEY_FILE },
		{ "ecdsa", "ECDSA",_PATH_HOST_ECDSA_KEY_FILE },
#endif /* WITH_OPENSSL */
		{ "ed25519", "ED25519",_PATH_HOST_ED25519_KEY_FILE },
		{ NULL, NULL, NULL }
	};

	int first = 0;
	struct stat st;
	struct sshkey *private, *public;
	char comment[1024];
	int i, type, fd, r;
	FILE *f;

	for (i = 0; key_types[i].key_type; i++) {
		if (stat(key_types[i].path, &st) == 0)
			continue;
		if (errno != ENOENT) {
			error("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);
		type = sshkey_type_from_name(key_types[i].key_type);
		strlcpy(identity_file, key_types[i].path, sizeof(identity_file));
		bits = 0;
		type_bits_valid(type, NULL, &bits);
		if ((r = sshkey_generate(type, bits, &private)) != 0) {
			error("key_generate failed: %s", ssh_err(r));
			first = 0;
			continue;
		}
		if ((r = sshkey_from_private(private, &public)) != 0)
			fatal("sshkey_from_private failed: %s", ssh_err(r));
		snprintf(comment, sizeof comment, "%s@%s", pw->pw_name,
		    hostname);
		if ((r = sshkey_save_private(private, identity_file, "",
		    comment, use_new_format, new_format_cipher, rounds)) != 0) {
			error("Saving key \"%s\" failed: %s",
			    identity_file, ssh_err(r));
			sshkey_free(private);
			sshkey_free(public);
			first = 0;
			continue;
		}
		sshkey_free(private);
		strlcat(identity_file, ".pub", sizeof(identity_file));
		fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
		if (fd == -1) {
			error("Could not save your public key in %s",
			    identity_file);
			sshkey_free(public);
			first = 0;
			continue;
		}
		f = fdopen(fd, "w");
		if (f == NULL) {
			error("fdopen %s failed", identity_file);
			close(fd);
			sshkey_free(public);
			first = 0;
			continue;
		}
		if ((r = sshkey_write(public, f)) != 0) {
			error("write key failed: %s", ssh_err(r));
			fclose(f);
			sshkey_free(public);
			first = 0;
			continue;
		}
		fprintf(f, " %s\n", comment);
		fclose(f);
		sshkey_free(public);

	}
	if (first != 0)
		printf("\n");
}

struct known_hosts_ctx {
	const char *host;	/* Hostname searched for in find/delete case */
	FILE *out;		/* Output file, stdout for find_hosts case */
	int has_unhashed;	/* When hashing, original had unhashed hosts */
	int found_key;		/* For find/delete, host was found */
	int invalid;		/* File contained invalid items; don't delete */
};

static int
known_hosts_hash(struct hostkey_foreach_line *l, void *_ctx)
{
	struct known_hosts_ctx *ctx = (struct known_hosts_ctx *)_ctx;
	char *hashed, *cp, *hosts, *ohosts;
	int has_wild = l->hosts && strcspn(l->hosts, "*?!") != strlen(l->hosts);

	switch (l->status) {
	case HKF_STATUS_OK:
	case HKF_STATUS_MATCHED:
		/*
		 * Don't hash hosts already already hashed, with wildcard
		 * characters or a CA/revocation marker.
		 */
		if ((l->match & HKF_MATCH_HOST_HASHED) != 0 ||
		    has_wild || l->marker != MRK_NONE) {
			fprintf(ctx->out, "%s\n", l->line);
			if (has_wild && !find_host) {
				logit("%s:%ld: ignoring host name "
				    "with wildcard: %.64s", l->path,
				    l->linenum, l->hosts);
			}
			return 0;
		}
		/*
		 * Split any comma-separated hostnames from the host list,
		 * hash and store separately.
		 */
		ohosts = hosts = xstrdup(l->hosts);
		while ((cp = strsep(&hosts, ",")) != NULL && *cp != '\0') {
			if ((hashed = host_hash(cp, NULL, 0)) == NULL)
				fatal("hash_host failed");
			fprintf(ctx->out, "%s %s\n", hashed, l->rawkey);
			ctx->has_unhashed = 1;
		}
		free(ohosts);
		return 0;
	case HKF_STATUS_INVALID:
		/* Retain invalid lines, but mark file as invalid. */
		ctx->invalid = 1;
		logit("%s:%ld: invalid line", l->path, l->linenum);
		/* FALLTHROUGH */
	default:
		fprintf(ctx->out, "%s\n", l->line);
		return 0;
	}
	/* NOTREACHED */
	return -1;
}

static int
known_hosts_find_delete(struct hostkey_foreach_line *l, void *_ctx)
{
	struct known_hosts_ctx *ctx = (struct known_hosts_ctx *)_ctx;

	if (l->status == HKF_STATUS_MATCHED) {
		if (delete_host) {
			if (l->marker != MRK_NONE) {
				/* Don't remove CA and revocation lines */
				fprintf(ctx->out, "%s\n", l->line);
			} else {
				/*
				 * Hostname matches and has no CA/revoke
				 * marker, delete it by *not* writing the
				 * line to ctx->out.
				 */
				ctx->found_key = 1;
				if (!quiet)
					printf("# Host %s found: line %ld\n",
					    ctx->host, l->linenum);
			}
			return 0;
		} else if (find_host) {
			ctx->found_key = 1;
			if (!quiet) {
				printf("# Host %s found: line %ld %s\n",
				    ctx->host,
				    l->linenum, l->marker == MRK_CA ? "CA" :
				    (l->marker == MRK_REVOKE ? "REVOKED" : ""));
			}
			if (hash_hosts)
				known_hosts_hash(l, ctx);
			else
				fprintf(ctx->out, "%s\n", l->line);
			return 0;
		}
	} else if (delete_host) {
		/* Retain non-matching hosts when deleting */
		if (l->status == HKF_STATUS_INVALID) {
			ctx->invalid = 1;
			logit("%s:%ld: invalid line", l->path, l->linenum);
		}
		fprintf(ctx->out, "%s\n", l->line);
	}
	return 0;
}

static void
do_known_hosts(struct passwd *pw, const char *name)
{
	char *cp, tmp[PATH_MAX], old[PATH_MAX];
	int r, fd, oerrno, inplace = 0;
	struct known_hosts_ctx ctx;

	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");
		free(cp);
		have_identity = 1;
	}

	memset(&ctx, 0, sizeof(ctx));
	ctx.out = stdout;
	ctx.host = name;

	/*
	 * 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 ((fd = mkstemp(tmp)) == -1)
			fatal("mkstemp: %s", strerror(errno));
		if ((ctx.out = fdopen(fd, "w")) == NULL) {
			oerrno = errno;
			unlink(tmp);
			fatal("fdopen: %s", strerror(oerrno));
		}
		inplace = 1;
	}

	/* XXX support identity_file == "-" for stdin */
	if ((r = hostkeys_foreach(identity_file,
	    hash_hosts ? known_hosts_hash : known_hosts_find_delete, &ctx,
	    name, NULL, find_host ? HKF_WANT_MATCH : 0)) != 0)
		fatal("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));

	if (inplace)
		fclose(ctx.out);

	if (ctx.invalid) {
		error("%s is not a valid known_hosts file.", identity_file);
		if (inplace) {
			error("Not replacing existing known_hosts "
			    "file because of errors");
			unlink(tmp);
		}
		exit(1);
	} else if (delete_host && !ctx.found_key) {
		logit("Host %s not found in %s", name, identity_file);
		unlink(tmp);
	} else if (inplace) {
		/* 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);
		}

		printf("%s updated.\n", identity_file);
		printf("Original contents retained as %s\n", old);
		if (ctx.has_unhashed) {
			logit("WARNING: %s contains unhashed entries", old);
			logit("Delete this file to ensure privacy "
			    "of hostnames");
		}
	}

	exit (find_host && !ctx.found_key);
}

/*
 * 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;
	struct sshkey *private;
	int r;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0)
		fatal("%s: %s", identity_file, strerror(errno));
	/* Try to load the file with empty passphrase. */
	r = sshkey_load_private(identity_file, "", &private, &comment);
	if (r == SSH_ERR_KEY_WRONG_PASSPHRASE) {
		if (identity_passphrase)
			old_passphrase = xstrdup(identity_passphrase);
		else
			old_passphrase =
			    read_passphrase("Enter old passphrase: ",
			    RP_ALLOW_STDIN);
		r = sshkey_load_private(identity_file, old_passphrase,
		    &private, &comment);
		explicit_bzero(old_passphrase, strlen(old_passphrase));
		free(old_passphrase);
		if (r != 0)
			goto badkey;
	} else if (r != 0) {
 badkey:
		fatal("Failed to load key %s: %s", identity_file, ssh_err(r));
	}
	if (comment)
		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) {
			explicit_bzero(passphrase1, strlen(passphrase1));
			explicit_bzero(passphrase2, strlen(passphrase2));
			free(passphrase1);
			free(passphrase2);
			printf("Pass phrases do not match.  Try again.\n");
			exit(1);
		}
		/* Destroy the other copy. */
		explicit_bzero(passphrase2, strlen(passphrase2));
		free(passphrase2);
	}

	/* Save the file using the new passphrase. */
	if ((r = sshkey_save_private(private, identity_file, passphrase1,
	    comment, use_new_format, new_format_cipher, rounds)) != 0) {
		error("Saving key \"%s\" failed: %s.",
		    identity_file, ssh_err(r));
		explicit_bzero(passphrase1, strlen(passphrase1));
		free(passphrase1);
		sshkey_free(private);
		free(comment);
		exit(1);
	}
	/* Destroy the passphrase and the copy of the key in memory. */
	explicit_bzero(passphrase1, strlen(passphrase1));
	free(passphrase1);
	sshkey_free(private);		 /* Destroys contents */
	free(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)
{
	struct sshkey *public;
	char *comment = NULL;
	struct stat st;
	int r;

	if (fname == NULL)
		fatal("%s: no filename", __func__);
	if (stat(fname, &st) < 0) {
		if (errno == ENOENT)
			return 0;
		fatal("%s: %s", fname, strerror(errno));
	}
	if ((r = sshkey_load_public(fname, &public, &comment)) != 0)
		fatal("Failed to read v2 public key from \"%s\": %s.",
		    fname, ssh_err(r));
	export_dns_rr(hname, public, stdout, print_generic);
	sshkey_free(public);
	free(comment);
	return 1;
}

/*
 * Change the comment of a private key file.
 */
static void
do_change_comment(struct passwd *pw)
{
	char new_comment[1024], *comment, *passphrase;
	struct sshkey *private;
	struct sshkey *public;
	struct stat st;
	FILE *f;
	int r, fd;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0)
		fatal("%s: %s", identity_file, strerror(errno));
	if ((r = sshkey_load_private(identity_file, "",
	    &private, &comment)) == 0)
		passphrase = xstrdup("");
	else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE)
		fatal("Cannot load private key \"%s\": %s.",
		    identity_file, ssh_err(r));
	else {
		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. */
		if ((r = sshkey_load_private(identity_file, passphrase,
		    &private, &comment)) != 0) {
			explicit_bzero(passphrase, strlen(passphrase));
			free(passphrase);
			fatal("Cannot load private key \"%s\": %s.",
			    identity_file, ssh_err(r));
		}
	}
	/* XXX what about new-format keys? */
	if (private->type != KEY_RSA1) {
		error("Comments are only supported for RSA1 keys.");
		explicit_bzero(passphrase, strlen(passphrase));
		sshkey_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)) {
			explicit_bzero(passphrase, strlen(passphrase));
			sshkey_free(private);
			exit(1);
		}
		new_comment[strcspn(new_comment, "\n")] = '\0';
	}

	/* Save the file using the new passphrase. */
	if ((r = sshkey_save_private(private, identity_file, passphrase,
	    new_comment, use_new_format, new_format_cipher, rounds)) != 0) {
		error("Saving key \"%s\" failed: %s",
		    identity_file, ssh_err(r));
		explicit_bzero(passphrase, strlen(passphrase));
		free(passphrase);
		sshkey_free(private);
		free(comment);
		exit(1);
	}
	explicit_bzero(passphrase, strlen(passphrase));
	free(passphrase);
	if ((r = sshkey_from_private(private, &public)) != 0)
		fatal("key_from_private failed: %s", ssh_err(r));
	sshkey_free(private);

	strlcat(identity_file, ".pub", sizeof(identity_file));
	fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
	if (fd == -1)
		fatal("Could not save your public key in %s", identity_file);
	f = fdopen(fd, "w");
	if (f == NULL)
		fatal("fdopen %s failed: %s", identity_file, strerror(errno));
	if ((r = sshkey_write(public, f)) != 0)
		fatal("write key failed: %s", ssh_err(r));
	sshkey_free(public);
	fprintf(f, " %s\n", new_comment);
	fclose(f);

	free(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(struct sshbuf *c, const char *name)
{
	int r;

	debug3("%s: %s", __func__, name);
	if ((r = sshbuf_put_cstring(c, name)) != 0 ||
	    (r = sshbuf_put_string(c, NULL, 0)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));
}

static void
add_string_option(struct sshbuf *c, const char *name, const char *value)
{
	struct sshbuf *b;
	int r;

	debug3("%s: %s=%s", __func__, name, value);
	if ((b = sshbuf_new()) == NULL)
		fatal("%s: sshbuf_new failed", __func__);
	if ((r = sshbuf_put_cstring(b, value)) != 0 ||
	    (r = sshbuf_put_cstring(c, name)) != 0 ||
	    (r = sshbuf_put_stringb(c, b)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));

	sshbuf_free(b);
}

#define OPTIONS_CRITICAL	1
#define OPTIONS_EXTENSIONS	2
static void
prepare_options_buf(struct sshbuf *c, int which)
{
	sshbuf_reset(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 struct sshkey *
load_pkcs11_key(char *path)
{
#ifdef ENABLE_PKCS11
	struct sshkey **keys = NULL, *public, *private = NULL;
	int r, i, nkeys;

	if ((r = sshkey_load_public(path, &public, NULL)) != 0)
		fatal("Couldn't load CA public key \"%s\": %s",
		    path, ssh_err(r));

	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 (sshkey_equal_public(public, keys[i])) {
			private = keys[i];
			continue;
		}
		sshkey_free(keys[i]);
	}
	free(keys);
	sshkey_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 r, i, fd;
	u_int n;
	struct sshkey *ca, *public;
	char *otmp, *tmp, *cp, *out, *comment, **plist = NULL;
	FILE *f;
	int v00 = 0; /* legacy keys */

	if (key_type_name != NULL) {
		switch (sshkey_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:
			fatal("unknown key type %s", key_type_name);
		}
	}

#ifdef ENABLE_PKCS11
	pkcs11_init(1);
#endif
	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
		ca = load_identity(tmp);
	free(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 = xreallocarray(plist, n + 1, sizeof(*plist));
				if (*(plist[n] = xstrdup(cp)) == '\0')
					fatal("Empty principal name");
			}
			free(otmp);
		}

		tmp = tilde_expand_filename(argv[i], pw->pw_uid);
		if ((r = sshkey_load_public(tmp, &public, &comment)) != 0)
			fatal("%s: unable to open \"%s\": %s",
			    __func__, tmp, ssh_err(r));
		if (public->type != KEY_RSA && public->type != KEY_DSA &&
		    public->type != KEY_ECDSA && public->type != KEY_ED25519)
			fatal("%s: key \"%s\" type %s cannot be certified",
			    __func__, tmp, sshkey_type(public));

		/* Prepare certificate to sign */
		if ((r = sshkey_to_certified(public, v00)) != 0)
			fatal("Could not upgrade key %s to certificate: %s",
			    tmp, ssh_err(r));
		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);
		}
		if ((r = sshkey_from_private(ca,
		    &public->cert->signature_key)) != 0)
			fatal("key_from_private (ca key): %s", ssh_err(r));

		if (sshkey_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);
		free(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 ((r = sshkey_write(public, f)) != 0)
			fatal("Could not write certified key to %s: %s",
			    out, ssh_err(r));
		fprintf(f, " %s\n", comment);
		fclose(f);

		if (!quiet) {
			logit("Signed %s key %s: id \"%s\" serial %llu%s%s "
			    "valid %s", sshkey_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));
		}

		sshkey_free(public);
		free(out);
	}
#ifdef ENABLE_PKCS11
	pkcs11_terminate();
#endif
	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);
	}

	memset(&tm, 0, 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, now);
	else
		cert_valid_to = parse_absolute_time(to);

	if (cert_valid_to <= cert_valid_from)
		fatal("Empty certificate validity interval");
	free(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(struct sshbuf *optbuf, int v00, int in_critical)
{
	char *name, *arg;
	struct sshbuf *options, *option = NULL;
	int r;

	if ((options = sshbuf_fromb(optbuf)) == NULL)
		fatal("%s: sshbuf_fromb failed", __func__);
	while (sshbuf_len(options) != 0) {
		sshbuf_free(option);
		option = NULL;
		if ((r = sshbuf_get_cstring(options, &name, NULL)) != 0 ||
		    (r = sshbuf_froms(options, &option)) != 0)
			fatal("%s: buffer error: %s", __func__, ssh_err(r));
		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)) {
			if ((r = sshbuf_get_cstring(option, &arg, NULL)) != 0)
				fatal("%s: buffer error: %s",
				    __func__, ssh_err(r));
			printf(" %s\n", arg);
			free(arg);
		} else {
			printf(" UNKNOWN OPTION (len %zu)\n",
			    sshbuf_len(option));
			sshbuf_reset(option);
		}
		free(name);
		if (sshbuf_len(option) != 0)
			fatal("Option corrupt: extra data at end");
	}
	sshbuf_free(option);
	sshbuf_free(options);
}

static void
do_show_cert(struct passwd *pw)
{
	struct sshkey *key;
	struct stat st;
	char *key_fp, *ca_fp;
	u_int i, v00;
	int r;

	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 ((r = sshkey_load_public(identity_file, &key, NULL)) != 0)
		fatal("Cannot load public key \"%s\": %s",
		    identity_file, ssh_err(r));
	if (!sshkey_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 = sshkey_fingerprint(key, fingerprint_hash, SSH_FP_DEFAULT);
	ca_fp = sshkey_fingerprint(key->cert->signature_key,
	    fingerprint_hash, SSH_FP_DEFAULT);
	if (key_fp == NULL || ca_fp == NULL)
		fatal("%s: sshkey_fingerprint fail", __func__);

	printf("%s:\n", identity_file);
	printf("        Type: %s %s certificate\n", sshkey_ssh_name(key),
	    sshkey_cert_type(key));
	printf("        Public key: %s %s\n", sshkey_type(key), key_fp);
	printf("        Signing CA: %s %s\n",
	    sshkey_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 (sshbuf_len(key->cert->critical) == 0)
		printf("(none)\n");
	else {
		printf("\n");
		show_options(key->cert->critical, v00, 1);
	}
	if (!v00) {
		printf("        Extensions: ");
		if (sshbuf_len(key->cert->extensions) == 0)
			printf("(none)\n");
		else {
			printf("\n");
			show_options(key->cert->extensions, v00, 0);
		}
	}
	exit(0);
}

#ifdef WITH_OPENSSL
static void
load_krl(const char *path, struct ssh_krl **krlp)
{
	struct sshbuf *krlbuf;
	int r, fd;

	if ((krlbuf = sshbuf_new()) == NULL)
		fatal("sshbuf_new failed");
	if ((fd = open(path, O_RDONLY)) == -1)
		fatal("open %s: %s", path, strerror(errno));
	if ((r = sshkey_load_file(fd, krlbuf)) != 0)
		fatal("Unable to load KRL: %s", ssh_err(r));
	close(fd);
	/* XXX check sigs */
	if ((r = ssh_krl_from_blob(krlbuf, krlp, NULL, 0)) != 0 ||
	    *krlp == NULL)
		fatal("Invalid KRL file: %s", ssh_err(r));
	sshbuf_free(krlbuf);
}

static void
update_krl_from_file(struct passwd *pw, const char *file, int wild_ca,
    const struct sshkey *ca, struct ssh_krl *krl)
{
	struct sshkey *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 && !wild_ca) {
				fatal("revoking certificates 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 && !wild_ca) {
				fatal("revoking certificates 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 = sshkey_new(KEY_UNSPEC)) == NULL)
				fatal("key_new");
			if ((r = sshkey_read(key, &cp)) != 0)
				fatal("%s:%lu: invalid key: %s",
				    path, lnum, ssh_err(r));
			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: %s",
				    __func__, ssh_err(r));
			sshkey_free(key);
		}
	}
	if (strcmp(path, "-") != 0)
		fclose(krl_spec);
	free(path);
}

static void
do_gen_krl(struct passwd *pw, int updating, int argc, char **argv)
{
	struct ssh_krl *krl;
	struct stat sb;
	struct sshkey *ca = NULL;
	int fd, i, r, wild_ca = 0;
	char *tmp;
	struct sshbuf *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) {
		if (strcasecmp(ca_key_path, "none") == 0)
			wild_ca = 1;
		else {
			tmp = tilde_expand_filename(ca_key_path, pw->pw_uid);
			if ((r = sshkey_load_public(tmp, &ca, NULL)) != 0)
				fatal("Cannot load CA public key %s: %s",
				    tmp, ssh_err(r));
			free(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], wild_ca, ca, krl);

	if ((kbuf = sshbuf_new()) == NULL)
		fatal("sshbuf_new failed");
	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, (void *)sshbuf_ptr(kbuf), sshbuf_len(kbuf)) !=
	    sshbuf_len(kbuf))
		fatal("write %s: %s", identity_file, strerror(errno));
	close(fd);
	sshbuf_free(kbuf);
	ssh_krl_free(krl);
	if (ca != NULL)
		sshkey_free(ca);
}

static void
do_check_krl(struct passwd *pw, int argc, char **argv)
{
	int i, r, ret = 0;
	char *comment;
	struct ssh_krl *krl;
	struct sshkey *k;

	if (*identity_file == '\0')
		fatal("KRL checking requires an input file");
	load_krl(identity_file, &krl);
	for (i = 0; i < argc; i++) {
		if ((r = sshkey_load_public(argv[i], &k, &comment)) != 0)
			fatal("Cannot load public key %s: %s",
			    argv[i], ssh_err(r));
		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;
		sshkey_free(k);
		free(comment);
	}
	ssh_krl_free(krl);
	exit(ret);
}
#endif

static void
usage(void)
{
	fprintf(stderr,
	    "usage: ssh-keygen [-q] [-b bits] [-t dsa | ecdsa | ed25519 | rsa | rsa1]\n"
	    "                  [-N new_passphrase] [-C comment] [-f output_keyfile]\n"
	    "       ssh-keygen -p [-P old_passphrase] [-N new_passphrase] [-f keyfile]\n"
	    "       ssh-keygen -i [-m key_format] [-f input_keyfile]\n"
	    "       ssh-keygen -e [-m key_format] [-f input_keyfile]\n"
	    "       ssh-keygen -y [-f input_keyfile]\n"
	    "       ssh-keygen -c [-P passphrase] [-C comment] [-f keyfile]\n"
	    "       ssh-keygen -l [-v] [-E fingerprint_hash] [-f input_keyfile]\n"
	    "       ssh-keygen -B [-f input_keyfile]\n");
#ifdef ENABLE_PKCS11
	fprintf(stderr,
	    "       ssh-keygen -D pkcs11\n");
#endif
	fprintf(stderr,
	    "       ssh-keygen -F hostname [-f known_hosts_file] [-l]\n"
	    "       ssh-keygen -H [-f known_hosts_file]\n"
	    "       ssh-keygen -R hostname [-f known_hosts_file]\n"
	    "       ssh-keygen -r hostname [-f input_keyfile] [-g]\n"
	    "       ssh-keygen -G output_file [-v] [-b bits] [-M memory] [-S start_point]\n"
	    "       ssh-keygen -T output_file -f input_file [-v] [-a rounds] [-J num_lines]\n"
	    "                  [-j start_line] [-K checkpt] [-W generator]\n"
	    "       ssh-keygen -s ca_key -I certificate_identity [-h] [-n principals]\n"
	    "                  [-O option] [-V validity_interval] [-z serial_number] file ...\n"
	    "       ssh-keygen -L [-f input_keyfile]\n"
	    "       ssh-keygen -A\n"
	    "       ssh-keygen -k -f krl_file [-u] [-s ca_public] [-z version_number]\n"
	    "                  file ...\n"
	    "       ssh-keygen -Q -f krl_file file ...\n");
	exit(1);
}

/*
 * Main program for key management.
 */
int
main(int argc, char **argv)
{
	char dotsshdir[PATH_MAX], comment[1024], *passphrase1, *passphrase2;
	char *checkpoint = NULL;
	char out_file[PATH_MAX], *rr_hostname = NULL, *ep, *fp, *ra;
	struct sshkey *private, *public;
	struct passwd *pw;
	struct stat st;
	int r, opt, type, fd;
	u_int32_t memory = 0, generator_wanted = 0;
	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();

	OpenSSL_add_all_algorithms();
	log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);

	/* we need this for the home * directory.  */
	pw = getpwuid(getuid());
	if (!pw)
		fatal("No user exists for uid %lu", (u_long)getuid());
	if (gethostname(hostname, sizeof(hostname)) < 0)
		fatal("gethostname: %s", strerror(errno));

	/* Remaining characters: UYdw */
	while ((opt = getopt(argc, argv, "ABHLQXceghiklopquvxy"
	    "C:D:E:F:G:I:J:K:M:N:O:P:R:S:T:V:W:Z:"
	    "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 'E':
			fingerprint_hash = ssh_digest_alg_by_name(optarg);
			if (fingerprint_hash == -1)
				fatal("Invalid hash algorithm \"%s\"", optarg);
			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 'o':
			use_new_format = 1;
			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 'Z':
			new_format_cipher = 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':
			rounds = (int)strtonum(optarg, 1, INT_MAX, &errstr);
			if (errstr)
				fatal("Invalid number: %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) >= PATH_MAX)
				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) {
			error("Too few arguments.");
			usage();
		}
	} else if (argc > 0 && !gen_krl && !check_krl) {
		error("Too many arguments.");
		usage();
	}
	if (change_passphrase && change_comment) {
		error("Can only have one of -p and -c.");
		usage();
	}
	if (print_fingerprint && (delete_host || hash_hosts)) {
		error("Cannot use -l with -H or -R.");
		usage();
	}
#ifdef WITH_OPENSSL
	if (gen_krl) {
		do_gen_krl(pw, update_krl, argc, argv);
		return (0);
	}
	if (check_krl) {
		do_check_krl(pw, argc, argv);
		return (0);
	}
#endif
	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);
#ifdef WITH_OPENSSL
	if (convert_to)
		do_convert_to(pw);
	if (convert_from)
		do_convert_from(pw);
#endif
	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)
				fatal("%s: %s", identity_file, strerror(errno));
			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);
			n += do_print_resource_record(pw,
			    _PATH_HOST_ED25519_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, rounds == 0 ? 100 : rounds,
		    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);
	}

	if (key_type_name == NULL)
		key_type_name = "rsa";

	type = sshkey_type_from_name(key_type_name);
	type_bits_valid(type, key_type_name, &bits);

	if (!quiet)
		printf("Generating public/private %s key pair.\n",
		    key_type_name);
	if ((r = sshkey_generate(type, bits, &private)) != 0)
		fatal("key_generate failed");
	if ((r = sshkey_from_private(private, &public)) != 0)
		fatal("key_from_private failed: %s\n", ssh_err(r));

	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.
			 */
			explicit_bzero(passphrase1, strlen(passphrase1));
			explicit_bzero(passphrase2, strlen(passphrase2));
			free(passphrase1);
			free(passphrase2);
			printf("Passphrases do not match.  Try again.\n");
			goto passphrase_again;
		}
		/* Clear the other copy of the passphrase. */
		explicit_bzero(passphrase2, strlen(passphrase2));
		free(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 ((r = sshkey_save_private(private, identity_file, passphrase1,
	    comment, use_new_format, new_format_cipher, rounds)) != 0) {
		error("Saving key \"%s\" failed: %s",
		    identity_file, ssh_err(r));
		explicit_bzero(passphrase1, strlen(passphrase1));
		free(passphrase1);
		exit(1);
	}
	/* Clear the passphrase. */
	explicit_bzero(passphrase1, strlen(passphrase1));
	free(passphrase1);

	/* Clear the private key and the random number generator. */
	sshkey_free(private);

	if (!quiet)
		printf("Your identification has been saved in %s.\n", identity_file);

	strlcat(identity_file, ".pub", sizeof(identity_file));
	if ((fd = open(identity_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
		fatal("Unable to save public key to %s: %s",
		    identity_file, strerror(errno));
	if ((f = fdopen(fd, "w")) == NULL)
		fatal("fdopen %s failed: %s", identity_file, strerror(errno));
	if ((r = sshkey_write(public, f)) != 0)
		error("write key failed: %s", ssh_err(r));
	fprintf(f, " %s\n", comment);
	fclose(f);

	if (!quiet) {
		fp = sshkey_fingerprint(public, fingerprint_hash,
		    SSH_FP_DEFAULT);
		ra = sshkey_fingerprint(public, fingerprint_hash,
		    SSH_FP_RANDOMART);
		if (fp == NULL || ra == NULL)
			fatal("sshkey_fingerprint failed");
		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);
		free(ra);
		free(fp);
	}

	sshkey_free(public);
	exit(0);
}