Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1014 insertions, 0 deletions

diff --git a/ssh-add.c b/ssh-add.c
new file mode 100644
index 0000000..777f21e
--- /dev/null
+++ b/ssh-add.c
@@ -0,0 +1,1014 @@
+/* $OpenBSD: ssh-add.c,v 1.166 2022/06/18 02:17:16 dtucker Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * Adds an identity to the authentication server, or removes an identity.
+ *
+ * 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".
+ *
+ * SSH2 implementation,
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifdef WITH_OPENSSL
+# include <openssl/evp.h>
+# include "openbsd-compat/openssl-compat.h"
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "log.h"
+#include "sshkey.h"
+#include "sshbuf.h"
+#include "authfd.h"
+#include "authfile.h"
+#include "pathnames.h"
+#include "misc.h"
+#include "ssherr.h"
+#include "digest.h"
+#include "ssh-sk.h"
+#include "sk-api.h"
+#include "hostfile.h"
+
+/* argv0 */
+extern char *__progname;
+
+/* Default files to add */
+static char *default_files[] = {
+#ifdef WITH_OPENSSL
+	_PATH_SSH_CLIENT_ID_RSA,
+#ifdef OPENSSL_HAS_ECC
+	_PATH_SSH_CLIENT_ID_ECDSA,
+	_PATH_SSH_CLIENT_ID_ECDSA_SK,
+#endif
+#endif /* WITH_OPENSSL */
+	_PATH_SSH_CLIENT_ID_ED25519,
+	_PATH_SSH_CLIENT_ID_ED25519_SK,
+	_PATH_SSH_CLIENT_ID_XMSS,
+	_PATH_SSH_CLIENT_ID_DSA,
+	NULL
+};
+
+static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
+
+/* Default lifetime (0 == forever) */
+static int lifetime = 0;
+
+/* User has to confirm key use */
+static int confirm = 0;
+
+/* Maximum number of signatures (XMSS) */
+static u_int maxsign = 0;
+static u_int minleft = 0;
+
+/* we keep a cache of one passphrase */
+static char *pass = NULL;
+static void
+clear_pass(void)
+{
+	if (pass) {
+		freezero(pass, strlen(pass));
+		pass = NULL;
+	}
+}
+
+static int
+delete_one(int agent_fd, const struct sshkey *key, const char *comment,
+    const char *path, int qflag)
+{
+	int r;
+
+	if ((r = ssh_remove_identity(agent_fd, key)) != 0) {
+		fprintf(stderr, "Could not remove identity \"%s\": %s\n",
+		    path, ssh_err(r));
+		return r;
+	}
+	if (!qflag) {
+		fprintf(stderr, "Identity removed: %s %s (%s)\n", path,
+		    sshkey_type(key), comment ? comment : "no comment");
+	}
+	return 0;
+}
+
+static int
+delete_stdin(int agent_fd, int qflag)
+{
+	char *line = NULL, *cp;
+	size_t linesize = 0;
+	struct sshkey *key = NULL;
+	int lnum = 0, r, ret = -1;
+
+	while (getline(&line, &linesize, stdin) != -1) {
+		lnum++;
+		sshkey_free(key);
+		key = NULL;
+		line[strcspn(line, "\n")] = '\0';
+		cp = line + strspn(line, " \t");
+		if (*cp == '#' || *cp == '\0')
+			continue;
+		if ((key = sshkey_new(KEY_UNSPEC)) == NULL)
+			fatal_f("sshkey_new");
+		if ((r = sshkey_read(key, &cp)) != 0) {
+			error_r(r, "(stdin):%d: invalid key", lnum);
+			continue;
+		}
+		if (delete_one(agent_fd, key, cp, "(stdin)", qflag) == 0)
+			ret = 0;
+	}
+	sshkey_free(key);
+	free(line);
+	return ret;
+}
+
+static int
+delete_file(int agent_fd, const char *filename, int key_only, int qflag)
+{
+	struct sshkey *public, *cert = NULL;
+	char *certpath = NULL, *comment = NULL;
+	int r, ret = -1;
+
+	if (strcmp(filename, "-") == 0)
+		return delete_stdin(agent_fd, qflag);
+
+	if ((r = sshkey_load_public(filename, &public,  &comment)) != 0) {
+		printf("Bad key file %s: %s\n", filename, ssh_err(r));
+		return -1;
+	}
+	if (delete_one(agent_fd, public, comment, filename, qflag) == 0)
+		ret = 0;
+
+	if (key_only)
+		goto out;
+
+	/* Now try to delete the corresponding certificate too */
+	free(comment);
+	comment = NULL;
+	xasprintf(&certpath, "%s-cert.pub", filename);
+	if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
+		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
+			error_r(r, "Failed to load certificate \"%s\"", certpath);
+		goto out;
+	}
+
+	if (!sshkey_equal_public(cert, public))
+		fatal("Certificate %s does not match private key %s",
+		    certpath, filename);
+
+	if (delete_one(agent_fd, cert, comment, certpath, qflag) == 0)
+		ret = 0;
+
+ out:
+	sshkey_free(cert);
+	sshkey_free(public);
+	free(certpath);
+	free(comment);
+
+	return ret;
+}
+
+/* Send a request to remove all identities. */
+static int
+delete_all(int agent_fd, int qflag)
+{
+	int ret = -1;
+
+	/*
+	 * Since the agent might be forwarded, old or non-OpenSSH, when asked
+	 * to remove all keys, attempt to remove both protocol v.1 and v.2
+	 * keys.
+	 */
+	if (ssh_remove_all_identities(agent_fd, 2) == 0)
+		ret = 0;
+	/* ignore error-code for ssh1 */
+	ssh_remove_all_identities(agent_fd, 1);
+
+	if (ret != 0)
+		fprintf(stderr, "Failed to remove all identities.\n");
+	else if (!qflag)
+		fprintf(stderr, "All identities removed.\n");
+
+	return ret;
+}
+
+static int
+add_file(int agent_fd, const char *filename, int key_only, int qflag,
+    const char *skprovider, struct dest_constraint **dest_constraints,
+    size_t ndest_constraints)
+{
+	struct sshkey *private, *cert;
+	char *comment = NULL;
+	char msg[1024], *certpath = NULL;
+	int r, fd, ret = -1;
+	size_t i;
+	u_int32_t left;
+	struct sshbuf *keyblob;
+	struct ssh_identitylist *idlist;
+
+	if (strcmp(filename, "-") == 0) {
+		fd = STDIN_FILENO;
+		filename = "(stdin)";
+	} else if ((fd = open(filename, O_RDONLY)) == -1) {
+		perror(filename);
+		return -1;
+	}
+
+	/*
+	 * Since we'll try to load a keyfile multiple times, permission errors
+	 * will occur multiple times, so check perms first and bail if wrong.
+	 */
+	if (fd != STDIN_FILENO) {
+		if (sshkey_perm_ok(fd, filename) != 0) {
+			close(fd);
+			return -1;
+		}
+	}
+	if ((r = sshbuf_load_fd(fd, &keyblob)) != 0) {
+		fprintf(stderr, "Error loading key \"%s\": %s\n",
+		    filename, ssh_err(r));
+		sshbuf_free(keyblob);
+		close(fd);
+		return -1;
+	}
+	close(fd);
+
+	/* At first, try empty passphrase */
+	if ((r = sshkey_parse_private_fileblob(keyblob, "", &private,
+	    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
+		fprintf(stderr, "Error loading key \"%s\": %s\n",
+		    filename, ssh_err(r));
+		goto fail_load;
+	}
+	/* try last */
+	if (private == NULL && pass != NULL) {
+		if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private,
+		    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
+			fprintf(stderr, "Error loading key \"%s\": %s\n",
+			    filename, ssh_err(r));
+			goto fail_load;
+		}
+	}
+	if (private == NULL) {
+		/* clear passphrase since it did not work */
+		clear_pass();
+		snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ",
+		    filename, confirm ? " (will confirm each use)" : "");
+		for (;;) {
+			pass = read_passphrase(msg, RP_ALLOW_STDIN);
+			if (strcmp(pass, "") == 0)
+				goto fail_load;
+			if ((r = sshkey_parse_private_fileblob(keyblob, pass,
+			    &private, &comment)) == 0)
+				break;
+			else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
+				fprintf(stderr,
+				    "Error loading key \"%s\": %s\n",
+				    filename, ssh_err(r));
+ fail_load:
+				clear_pass();
+				sshbuf_free(keyblob);
+				return -1;
+			}
+			clear_pass();
+			snprintf(msg, sizeof msg,
+			    "Bad passphrase, try again for %s%s: ", filename,
+			    confirm ? " (will confirm each use)" : "");
+		}
+	}
+	if (comment == NULL || *comment == '\0')
+		comment = xstrdup(filename);
+	sshbuf_free(keyblob);
+
+	/* For XMSS */
+	if ((r = sshkey_set_filename(private, filename)) != 0) {
+		fprintf(stderr, "Could not add filename to private key: %s (%s)\n",
+		    filename, comment);
+		goto out;
+	}
+	if (maxsign && minleft &&
+	    (r = ssh_fetch_identitylist(agent_fd, &idlist)) == 0) {
+		for (i = 0; i < idlist->nkeys; i++) {
+			if (!sshkey_equal_public(idlist->keys[i], private))
+				continue;
+			left = sshkey_signatures_left(idlist->keys[i]);
+			if (left < minleft) {
+				fprintf(stderr,
+				    "Only %d signatures left.\n", left);
+				break;
+			}
+			fprintf(stderr, "Skipping update: ");
+			if (left == minleft) {
+				fprintf(stderr,
+				    "required signatures left (%d).\n", left);
+			} else {
+				fprintf(stderr,
+				    "more signatures left (%d) than"
+				    " required (%d).\n", left, minleft);
+			}
+			ssh_free_identitylist(idlist);
+			goto out;
+		}
+		ssh_free_identitylist(idlist);
+	}
+
+	if (sshkey_is_sk(private)) {
+		if (skprovider == NULL) {
+			fprintf(stderr, "Cannot load FIDO key %s "
+			    "without provider\n", filename);
+			goto out;
+		}
+	} else {
+		/* Don't send provider constraint for other keys */
+		skprovider = NULL;
+	}
+
+	if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
+	    lifetime, confirm, maxsign, skprovider,
+	    dest_constraints, ndest_constraints)) == 0) {
+		ret = 0;
+		if (!qflag) {
+			fprintf(stderr, "Identity added: %s (%s)\n",
+			    filename, comment);
+			if (lifetime != 0) {
+				fprintf(stderr,
+				    "Lifetime set to %d seconds\n", lifetime);
+			}
+			if (confirm != 0) {
+				fprintf(stderr, "The user must confirm "
+				    "each use of the key\n");
+			}
+		}
+	} else {
+		fprintf(stderr, "Could not add identity \"%s\": %s\n",
+		    filename, ssh_err(r));
+	}
+
+	/* Skip trying to load the cert if requested */
+	if (key_only)
+		goto out;
+
+	/* Now try to add the certificate flavour too */
+	xasprintf(&certpath, "%s-cert.pub", filename);
+	if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
+		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
+			error_r(r, "Failed to load certificate \"%s\"", certpath);
+		goto out;
+	}
+
+	if (!sshkey_equal_public(cert, private)) {
+		error("Certificate %s does not match private key %s",
+		    certpath, filename);
+		sshkey_free(cert);
+		goto out;
+	}
+
+	/* Graft with private bits */
+	if ((r = sshkey_to_certified(private)) != 0) {
+		error_fr(r, "sshkey_to_certified");
+		sshkey_free(cert);
+		goto out;
+	}
+	if ((r = sshkey_cert_copy(cert, private)) != 0) {
+		error_fr(r, "sshkey_cert_copy");
+		sshkey_free(cert);
+		goto out;
+	}
+	sshkey_free(cert);
+
+	if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
+	    lifetime, confirm, maxsign, skprovider,
+	    dest_constraints, ndest_constraints)) != 0) {
+		error_r(r, "Certificate %s (%s) add failed", certpath,
+		    private->cert->key_id);
+		goto out;
+	}
+	/* success */
+	if (!qflag) {
+		fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
+		    private->cert->key_id);
+		if (lifetime != 0) {
+			fprintf(stderr, "Lifetime set to %d seconds\n",
+			    lifetime);
+		}
+		if (confirm != 0) {
+			fprintf(stderr, "The user must confirm each use "
+			    "of the key\n");
+		}
+	}
+
+ out:
+	free(certpath);
+	free(comment);
+	sshkey_free(private);
+
+	return ret;
+}
+
+static int
+update_card(int agent_fd, int add, const char *id, int qflag,
+    struct dest_constraint **dest_constraints, size_t ndest_constraints)
+{
+	char *pin = NULL;
+	int r, ret = -1;
+
+	if (add) {
+		if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
+		    RP_ALLOW_STDIN)) == NULL)
+			return -1;
+	}
+
+	if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
+	    lifetime, confirm, dest_constraints, ndest_constraints)) == 0) {
+		ret = 0;
+		if (!qflag) {
+			fprintf(stderr, "Card %s: %s\n",
+			    add ? "added" : "removed", id);
+		}
+	} else {
+		fprintf(stderr, "Could not %s card \"%s\": %s\n",
+		    add ? "add" : "remove", id, ssh_err(r));
+		ret = -1;
+	}
+	free(pin);
+	return ret;
+}
+
+static int
+test_key(int agent_fd, const char *filename)
+{
+	struct sshkey *key = NULL;
+	u_char *sig = NULL;
+	size_t slen = 0;
+	int r, ret = -1;
+	char data[1024];
+
+	if ((r = sshkey_load_public(filename, &key, NULL)) != 0) {
+		error_r(r, "Couldn't read public key %s", filename);
+		return -1;
+	}
+	arc4random_buf(data, sizeof(data));
+	if ((r = ssh_agent_sign(agent_fd, key, &sig, &slen, data, sizeof(data),
+	    NULL, 0)) != 0) {
+		error_r(r, "Agent signature failed for %s", filename);
+		goto done;
+	}
+	if ((r = sshkey_verify(key, sig, slen, data, sizeof(data),
+	    NULL, 0, NULL)) != 0) {
+		error_r(r, "Signature verification failed for %s", filename);
+		goto done;
+	}
+	/* success */
+	ret = 0;
+ done:
+	free(sig);
+	sshkey_free(key);
+	return ret;
+}
+
+static int
+list_identities(int agent_fd, int do_fp)
+{
+	char *fp;
+	int r;
+	struct ssh_identitylist *idlist;
+	u_int32_t left;
+	size_t i;
+
+	if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) {
+		if (r != SSH_ERR_AGENT_NO_IDENTITIES)
+			fprintf(stderr, "error fetching identities: %s\n",
+			    ssh_err(r));
+		else
+			printf("The agent has no identities.\n");
+		return -1;
+	}
+	for (i = 0; i < idlist->nkeys; i++) {
+		if (do_fp) {
+			fp = sshkey_fingerprint(idlist->keys[i],
+			    fingerprint_hash, SSH_FP_DEFAULT);
+			printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]),
+			    fp == NULL ? "(null)" : fp, idlist->comments[i],
+			    sshkey_type(idlist->keys[i]));
+			free(fp);
+		} else {
+			if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) {
+				fprintf(stderr, "sshkey_write: %s\n",
+				    ssh_err(r));
+				continue;
+			}
+			fprintf(stdout, " %s", idlist->comments[i]);
+			left = sshkey_signatures_left(idlist->keys[i]);
+			if (left > 0)
+				fprintf(stdout,
+				    " [signatures left %d]", left);
+			fprintf(stdout, "\n");
+		}
+	}
+	ssh_free_identitylist(idlist);
+	return 0;
+}
+
+static int
+lock_agent(int agent_fd, int lock)
+{
+	char prompt[100], *p1, *p2;
+	int r, passok = 1, ret = -1;
+
+	strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
+	p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
+	if (lock) {
+		strlcpy(prompt, "Again: ", sizeof prompt);
+		p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
+		if (strcmp(p1, p2) != 0) {
+			fprintf(stderr, "Passwords do not match.\n");
+			passok = 0;
+		}
+		freezero(p2, strlen(p2));
+	}
+	if (passok) {
+		if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) {
+			fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
+			ret = 0;
+		} else {
+			fprintf(stderr, "Failed to %slock agent: %s\n",
+			    lock ? "" : "un", ssh_err(r));
+		}
+	}
+	freezero(p1, strlen(p1));
+	return (ret);
+}
+
+static int
+load_resident_keys(int agent_fd, const char *skprovider, int qflag,
+    struct dest_constraint **dest_constraints, size_t ndest_constraints)
+{
+	struct sshsk_resident_key **srks;
+	size_t nsrks, i;
+	struct sshkey *key;
+	int r, ok = 0;
+	char *fp;
+
+	pass = read_passphrase("Enter PIN for authenticator: ", RP_ALLOW_STDIN);
+	if ((r = sshsk_load_resident(skprovider, NULL, pass, 0,
+	    &srks, &nsrks)) != 0) {
+		error_r(r, "Unable to load resident keys");
+		return r;
+	}
+	for (i = 0; i < nsrks; i++) {
+		key = srks[i]->key;
+		if ((fp = sshkey_fingerprint(key,
+		    fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+			fatal_f("sshkey_fingerprint failed");
+		if ((r = ssh_add_identity_constrained(agent_fd, key, "",
+		    lifetime, confirm, maxsign, skprovider,
+		    dest_constraints, ndest_constraints)) != 0) {
+			error("Unable to add key %s %s",
+			    sshkey_type(key), fp);
+			free(fp);
+			ok = r;
+			continue;
+		}
+		if (ok == 0)
+			ok = 1;
+		if (!qflag) {
+			fprintf(stderr, "Resident identity added: %s %s\n",
+			    sshkey_type(key), fp);
+			if (lifetime != 0) {
+				fprintf(stderr,
+				    "Lifetime set to %d seconds\n", lifetime);
+			}
+			if (confirm != 0) {
+				fprintf(stderr, "The user must confirm "
+				    "each use of the key\n");
+			}
+		}
+		free(fp);
+	}
+	sshsk_free_resident_keys(srks, nsrks);
+	if (nsrks == 0)
+		return SSH_ERR_KEY_NOT_FOUND;
+	return ok == 1 ? 0 : ok;
+}
+
+static int
+do_file(int agent_fd, int deleting, int key_only, char *file, int qflag,
+    const char *skprovider, struct dest_constraint **dest_constraints,
+    size_t ndest_constraints)
+{
+	if (deleting) {
+		if (delete_file(agent_fd, file, key_only, qflag) == -1)
+			return -1;
+	} else {
+		if (add_file(agent_fd, file, key_only, qflag, skprovider,
+		    dest_constraints, ndest_constraints) == -1)
+			return -1;
+	}
+	return 0;
+}
+
+/* Append string 's' to a NULL-terminated array of strings */
+static void
+stringlist_append(char ***listp, const char *s)
+{
+	size_t i = 0;
+
+	if (*listp == NULL)
+		*listp = xcalloc(2, sizeof(**listp));
+	else {
+		for (i = 0; (*listp)[i] != NULL; i++)
+			; /* count */
+		*listp = xrecallocarray(*listp, i + 1, i + 2, sizeof(**listp));
+	}
+	(*listp)[i] = xstrdup(s);
+}
+
+static void
+parse_dest_constraint_hop(const char *s, struct dest_constraint_hop *dch,
+    char **hostkey_files)
+{
+	char *user = NULL, *host, *os, *path;
+	size_t i;
+	struct hostkeys *hostkeys;
+	const struct hostkey_entry *hke;
+	int r, want_ca;
+
+	memset(dch, '\0', sizeof(*dch));
+	os = xstrdup(s);
+	if ((host = strchr(os, '@')) == NULL)
+		host = os;
+	else {
+		*host++ = '\0';
+		user = os;
+	}
+	cleanhostname(host);
+	/* Trivial case: username@ (all hosts) */
+	if (*host == '\0') {
+		if (user == NULL) {
+			fatal("Invalid key destination constraint \"%s\": "
+			    "does not specify user or host", s);
+		}
+		dch->user = xstrdup(user);
+		/* other fields left blank */
+		free(os);
+		return;
+	}
+	if (hostkey_files == NULL)
+		fatal_f("no hostkey files");
+	/* Otherwise we need to look up the keys for this hostname */
+	hostkeys = init_hostkeys();
+	for (i = 0; hostkey_files[i]; i++) {
+		path = tilde_expand_filename(hostkey_files[i], getuid());
+		debug2_f("looking up host keys for \"%s\" in %s", host, path);
+                load_hostkeys(hostkeys, host, path, 0);
+		free(path);
+	}
+	dch->user = user == NULL ? NULL : xstrdup(user);
+	dch->hostname = xstrdup(host);
+	for (i = 0; i < hostkeys->num_entries; i++) {
+		hke = hostkeys->entries + i;
+		want_ca = hke->marker == MRK_CA;
+		if (hke->marker != MRK_NONE && !want_ca)
+			continue;
+		debug3_f("%s%s%s: adding %s %skey from %s:%lu as key %u",
+		    user == NULL ? "": user, user == NULL ? "" : "@",
+		    host, sshkey_type(hke->key), want_ca ? "CA " : "",
+		    hke->file, hke->line, dch->nkeys);
+		dch->keys = xrecallocarray(dch->keys, dch->nkeys,
+		    dch->nkeys + 1, sizeof(*dch->keys));
+		dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys,
+		    dch->nkeys + 1, sizeof(*dch->key_is_ca));
+		if ((r = sshkey_from_private(hke->key,
+		    &(dch->keys[dch->nkeys]))) != 0)
+			fatal_fr(r, "sshkey_from_private");
+		dch->key_is_ca[dch->nkeys] = want_ca;
+		dch->nkeys++;
+	}
+	if (dch->nkeys == 0)
+		fatal("No host keys found for destination \"%s\"", host);
+	free_hostkeys(hostkeys);
+	free(os);
+	return;
+}
+
+static void
+parse_dest_constraint(const char *s, struct dest_constraint ***dcp,
+    size_t *ndcp, char **hostkey_files)
+{
+	struct dest_constraint *dc;
+	char *os, *cp;
+
+	dc = xcalloc(1, sizeof(*dc));
+	os = xstrdup(s);
+	if ((cp = strchr(os, '>')) == NULL) {
+		/* initial hop; no 'from' hop specified */
+		parse_dest_constraint_hop(os, &dc->to, hostkey_files);
+	} else {
+		/* two hops specified */
+		*(cp++) = '\0';
+		parse_dest_constraint_hop(os, &dc->from, hostkey_files);
+		parse_dest_constraint_hop(cp, &dc->to, hostkey_files);
+		if (dc->from.user != NULL) {
+			fatal("Invalid key constraint %s: cannot specify "
+			    "user on 'from' host", os);
+		}
+	}
+	/* XXX eliminate or error on duplicates */
+	debug2_f("constraint %zu: %s%s%s (%u keys) > %s%s%s (%u keys)", *ndcp,
+	    dc->from.user ? dc->from.user : "", dc->from.user ? "@" : "",
+	    dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys,
+	    dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "",
+	    dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys);
+	*dcp = xrecallocarray(*dcp, *ndcp, *ndcp + 1, sizeof(**dcp));
+	(*dcp)[(*ndcp)++] = dc;
+	free(os);
+}
+
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+"usage: ssh-add [-cDdKkLlqvXx] [-E fingerprint_hash] [-H hostkey_file]\n"
+"               [-h destination_constraint] [-S provider] [-t life]\n"
+#ifdef WITH_XMSS
+"               [-M maxsign] [-m minleft]\n"
+#endif
+"               [file ...]\n"
+"       ssh-add -s pkcs11\n"
+"       ssh-add -e pkcs11\n"
+"       ssh-add -T pubkey ...\n"
+	);
+}
+
+int
+main(int argc, char **argv)
+{
+	extern char *optarg;
+	extern int optind;
+	int agent_fd;
+	char *pkcs11provider = NULL, *skprovider = NULL;
+	char **dest_constraint_strings = NULL, **hostkey_files = NULL;
+	int r, i, ch, deleting = 0, ret = 0, key_only = 0, do_download = 0;
+	int xflag = 0, lflag = 0, Dflag = 0, qflag = 0, Tflag = 0;
+	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
+	LogLevel log_level = SYSLOG_LEVEL_INFO;
+	struct dest_constraint **dest_constraints = NULL;
+	size_t ndest_constraints = 0;
+
+	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+	sanitise_stdfd();
+
+	__progname = ssh_get_progname(argv[0]);
+	seed_rng();
+
+	log_init(__progname, log_level, log_facility, 1);
+
+	setvbuf(stdout, NULL, _IOLBF, 0);
+
+	/* First, get a connection to the authentication agent. */
+	switch (r = ssh_get_authentication_socket(&agent_fd)) {
+	case 0:
+		break;
+	case SSH_ERR_AGENT_NOT_PRESENT:
+		fprintf(stderr, "Could not open a connection to your "
+		    "authentication agent.\n");
+		exit(2);
+	default:
+		fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
+		exit(2);
+	}
+
+	skprovider = getenv("SSH_SK_PROVIDER");
+
+	while ((ch = getopt(argc, argv, "vkKlLcdDTxXE:e:h:H:M:m:qs:S:t:")) != -1) {
+		switch (ch) {
+		case 'v':
+			if (log_level == SYSLOG_LEVEL_INFO)
+				log_level = SYSLOG_LEVEL_DEBUG1;
+			else if (log_level < SYSLOG_LEVEL_DEBUG3)
+				log_level++;
+			break;
+		case 'E':
+			fingerprint_hash = ssh_digest_alg_by_name(optarg);
+			if (fingerprint_hash == -1)
+				fatal("Invalid hash algorithm \"%s\"", optarg);
+			break;
+		case 'H':
+			stringlist_append(&hostkey_files, optarg);
+			break;
+		case 'h':
+			stringlist_append(&dest_constraint_strings, optarg);
+			break;
+		case 'k':
+			key_only = 1;
+			break;
+		case 'K':
+			do_download = 1;
+			break;
+		case 'l':
+		case 'L':
+			if (lflag != 0)
+				fatal("-%c flag already specified", lflag);
+			lflag = ch;
+			break;
+		case 'x':
+		case 'X':
+			if (xflag != 0)
+				fatal("-%c flag already specified", xflag);
+			xflag = ch;
+			break;
+		case 'c':
+			confirm = 1;
+			break;
+		case 'm':
+			minleft = (int)strtonum(optarg, 1, UINT_MAX, NULL);
+			if (minleft == 0) {
+				usage();
+				ret = 1;
+				goto done;
+			}
+			break;
+		case 'M':
+			maxsign = (int)strtonum(optarg, 1, UINT_MAX, NULL);
+			if (maxsign == 0) {
+				usage();
+				ret = 1;
+				goto done;
+			}
+			break;
+		case 'd':
+			deleting = 1;
+			break;
+		case 'D':
+			Dflag = 1;
+			break;
+		case 's':
+			pkcs11provider = optarg;
+			break;
+		case 'S':
+			skprovider = optarg;
+			break;
+		case 'e':
+			deleting = 1;
+			pkcs11provider = optarg;
+			break;
+		case 't':
+			if ((lifetime = convtime(optarg)) == -1 ||
+			    lifetime < 0 || (u_long)lifetime > UINT32_MAX) {
+				fprintf(stderr, "Invalid lifetime\n");
+				ret = 1;
+				goto done;
+			}
+			break;
+		case 'q':
+			qflag = 1;
+			break;
+		case 'T':
+			Tflag = 1;
+			break;
+		default:
+			usage();
+			ret = 1;
+			goto done;
+		}
+	}
+	log_init(__progname, log_level, log_facility, 1);
+
+	if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
+		fatal("Invalid combination of actions");
+	else if (xflag) {
+		if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
+			ret = 1;
+		goto done;
+	} else if (lflag) {
+		if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
+			ret = 1;
+		goto done;
+	} else if (Dflag) {
+		if (delete_all(agent_fd, qflag) == -1)
+			ret = 1;
+		goto done;
+	}
+
+#ifdef ENABLE_SK_INTERNAL
+	if (skprovider == NULL)
+		skprovider = "internal";
+#endif
+
+	if (hostkey_files == NULL) {
+		/* use defaults from readconf.c */
+		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE);
+		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE2);
+		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE);
+		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE2);
+	}
+	if (dest_constraint_strings != NULL) {
+		for (i = 0; dest_constraint_strings[i] != NULL; i++) {
+			parse_dest_constraint(dest_constraint_strings[i],
+			  &dest_constraints, &ndest_constraints, hostkey_files);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+	if (Tflag) {
+		if (argc <= 0)
+			fatal("no keys to test");
+		for (r = i = 0; i < argc; i++)
+			r |= test_key(agent_fd, argv[i]);
+		ret = r == 0 ? 0 : 1;
+		goto done;
+	}
+	if (pkcs11provider != NULL) {
+		if (update_card(agent_fd, !deleting, pkcs11provider,
+		    qflag, dest_constraints, ndest_constraints) == -1)
+			ret = 1;
+		goto done;
+	}
+	if (do_download) {
+		if (skprovider == NULL)
+			fatal("Cannot download keys without provider");
+		if (load_resident_keys(agent_fd, skprovider, qflag,
+		    dest_constraints, ndest_constraints) != 0)
+			ret = 1;
+		goto done;
+	}
+	if (argc == 0) {
+		char buf[PATH_MAX];
+		struct passwd *pw;
+		struct stat st;
+		int count = 0;
+
+		if ((pw = getpwuid(getuid())) == NULL) {
+			fprintf(stderr, "No user found with uid %u\n",
+			    (u_int)getuid());
+			ret = 1;
+			goto done;
+		}
+
+		for (i = 0; default_files[i]; i++) {
+			snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
+			    default_files[i]);
+			if (stat(buf, &st) == -1)
+				continue;
+			if (do_file(agent_fd, deleting, key_only, buf,
+			    qflag, skprovider,
+			    dest_constraints, ndest_constraints) == -1)
+				ret = 1;
+			else
+				count++;
+		}
+		if (count == 0)
+			ret = 1;
+	} else {
+		for (i = 0; i < argc; i++) {
+			if (do_file(agent_fd, deleting, key_only,
+			    argv[i], qflag, skprovider,
+			    dest_constraints, ndest_constraints) == -1)
+				ret = 1;
+		}
+	}
+done:
+	clear_pass();
+	ssh_close_authentication_socket(agent_fd);
+	return ret;
+}