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-rw-r--r--ssh-agent.c2272
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diff --git a/ssh-agent.c b/ssh-agent.c
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+/* $OpenBSD: ssh-agent.c,v 1.294 2022/12/04 11:03:11 dtucker Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * The authentication agent program.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ * Copyright (c) 2000, 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/resource.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#ifdef HAVE_SYS_UN_H
+# include <sys/un.h>
+#endif
+#include "openbsd-compat/sys-queue.h"
+
+#ifdef WITH_OPENSSL
+#include <openssl/evp.h>
+#include "openbsd-compat/openssl-compat.h"
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#ifdef HAVE_PATHS_H
+# include <paths.h>
+#endif
+#ifdef HAVE_POLL_H
+# include <poll.h>
+#endif
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef HAVE_UTIL_H
+# include <util.h>
+#endif
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "ssh2.h"
+#include "sshbuf.h"
+#include "sshkey.h"
+#include "authfd.h"
+#include "compat.h"
+#include "log.h"
+#include "misc.h"
+#include "digest.h"
+#include "ssherr.h"
+#include "match.h"
+#include "msg.h"
+#include "pathnames.h"
+#include "ssh-pkcs11.h"
+#include "sk-api.h"
+#include "myproposal.h"
+
+#ifndef DEFAULT_ALLOWED_PROVIDERS
+# define DEFAULT_ALLOWED_PROVIDERS "/usr/lib*/*,/usr/local/lib*/*"
+#endif
+
+/* Maximum accepted message length */
+#define AGENT_MAX_LEN (256*1024)
+/* Maximum bytes to read from client socket */
+#define AGENT_RBUF_LEN (4096)
+/* Maximum number of recorded session IDs/hostkeys per connection */
+#define AGENT_MAX_SESSION_IDS 16
+/* Maximum size of session ID */
+#define AGENT_MAX_SID_LEN 128
+/* Maximum number of destination constraints to accept on a key */
+#define AGENT_MAX_DEST_CONSTRAINTS 1024
+
+/* XXX store hostkey_sid in a refcounted tree */
+
+typedef enum {
+ AUTH_UNUSED = 0,
+ AUTH_SOCKET = 1,
+ AUTH_CONNECTION = 2,
+} sock_type;
+
+struct hostkey_sid {
+ struct sshkey *key;
+ struct sshbuf *sid;
+ int forwarded;
+};
+
+typedef struct socket_entry {
+ int fd;
+ sock_type type;
+ struct sshbuf *input;
+ struct sshbuf *output;
+ struct sshbuf *request;
+ size_t nsession_ids;
+ struct hostkey_sid *session_ids;
+} SocketEntry;
+
+u_int sockets_alloc = 0;
+SocketEntry *sockets = NULL;
+
+typedef struct identity {
+ TAILQ_ENTRY(identity) next;
+ struct sshkey *key;
+ char *comment;
+ char *provider;
+ time_t death;
+ u_int confirm;
+ char *sk_provider;
+ struct dest_constraint *dest_constraints;
+ size_t ndest_constraints;
+} Identity;
+
+struct idtable {
+ int nentries;
+ TAILQ_HEAD(idqueue, identity) idlist;
+};
+
+/* private key table */
+struct idtable *idtab;
+
+int max_fd = 0;
+
+/* pid of shell == parent of agent */
+pid_t parent_pid = -1;
+time_t parent_alive_interval = 0;
+
+/* pid of process for which cleanup_socket is applicable */
+pid_t cleanup_pid = 0;
+
+/* pathname and directory for AUTH_SOCKET */
+char socket_name[PATH_MAX];
+char socket_dir[PATH_MAX];
+
+/* Pattern-list of allowed PKCS#11/Security key paths */
+static char *allowed_providers;
+
+/* locking */
+#define LOCK_SIZE 32
+#define LOCK_SALT_SIZE 16
+#define LOCK_ROUNDS 1
+int locked = 0;
+u_char lock_pwhash[LOCK_SIZE];
+u_char lock_salt[LOCK_SALT_SIZE];
+
+extern char *__progname;
+
+/* Default lifetime in seconds (0 == forever) */
+static int lifetime = 0;
+
+static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
+
+/* Refuse signing of non-SSH messages for web-origin FIDO keys */
+static int restrict_websafe = 1;
+
+static void
+close_socket(SocketEntry *e)
+{
+ size_t i;
+
+ close(e->fd);
+ sshbuf_free(e->input);
+ sshbuf_free(e->output);
+ sshbuf_free(e->request);
+ for (i = 0; i < e->nsession_ids; i++) {
+ sshkey_free(e->session_ids[i].key);
+ sshbuf_free(e->session_ids[i].sid);
+ }
+ free(e->session_ids);
+ memset(e, '\0', sizeof(*e));
+ e->fd = -1;
+ e->type = AUTH_UNUSED;
+}
+
+static void
+idtab_init(void)
+{
+ idtab = xcalloc(1, sizeof(*idtab));
+ TAILQ_INIT(&idtab->idlist);
+ idtab->nentries = 0;
+}
+
+static void
+free_dest_constraint_hop(struct dest_constraint_hop *dch)
+{
+ u_int i;
+
+ if (dch == NULL)
+ return;
+ free(dch->user);
+ free(dch->hostname);
+ for (i = 0; i < dch->nkeys; i++)
+ sshkey_free(dch->keys[i]);
+ free(dch->keys);
+ free(dch->key_is_ca);
+}
+
+static void
+free_dest_constraints(struct dest_constraint *dcs, size_t ndcs)
+{
+ size_t i;
+
+ for (i = 0; i < ndcs; i++) {
+ free_dest_constraint_hop(&dcs[i].from);
+ free_dest_constraint_hop(&dcs[i].to);
+ }
+ free(dcs);
+}
+
+static void
+free_identity(Identity *id)
+{
+ sshkey_free(id->key);
+ free(id->provider);
+ free(id->comment);
+ free(id->sk_provider);
+ free_dest_constraints(id->dest_constraints, id->ndest_constraints);
+ free(id);
+}
+
+/*
+ * Match 'key' against the key/CA list in a destination constraint hop
+ * Returns 0 on success or -1 otherwise.
+ */
+static int
+match_key_hop(const char *tag, const struct sshkey *key,
+ const struct dest_constraint_hop *dch)
+{
+ const char *reason = NULL;
+ const char *hostname = dch->hostname ? dch->hostname : "(ORIGIN)";
+ u_int i;
+ char *fp;
+
+ if (key == NULL)
+ return -1;
+ /* XXX logspam */
+ if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug3_f("%s: entering hostname %s, requested key %s %s, %u keys avail",
+ tag, hostname, sshkey_type(key), fp, dch->nkeys);
+ free(fp);
+ for (i = 0; i < dch->nkeys; i++) {
+ if (dch->keys[i] == NULL)
+ return -1;
+ /* XXX logspam */
+ if ((fp = sshkey_fingerprint(dch->keys[i], SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug3_f("%s: key %u: %s%s %s", tag, i,
+ dch->key_is_ca[i] ? "CA " : "",
+ sshkey_type(dch->keys[i]), fp);
+ free(fp);
+ if (!sshkey_is_cert(key)) {
+ /* plain key */
+ if (dch->key_is_ca[i] ||
+ !sshkey_equal(key, dch->keys[i]))
+ continue;
+ return 0;
+ }
+ /* certificate */
+ if (!dch->key_is_ca[i])
+ continue;
+ if (key->cert == NULL || key->cert->signature_key == NULL)
+ return -1; /* shouldn't happen */
+ if (!sshkey_equal(key->cert->signature_key, dch->keys[i]))
+ continue;
+ if (sshkey_cert_check_host(key, hostname, 1,
+ SSH_ALLOWED_CA_SIGALGS, &reason) != 0) {
+ debug_f("cert %s / hostname %s rejected: %s",
+ key->cert->key_id, hostname, reason);
+ continue;
+ }
+ return 0;
+ }
+ return -1;
+}
+
+/* Check destination constraints on an identity against the hostkey/user */
+static int
+permitted_by_dest_constraints(const struct sshkey *fromkey,
+ const struct sshkey *tokey, Identity *id, const char *user,
+ const char **hostnamep)
+{
+ size_t i;
+ struct dest_constraint *d;
+
+ if (hostnamep != NULL)
+ *hostnamep = NULL;
+ for (i = 0; i < id->ndest_constraints; i++) {
+ d = id->dest_constraints + i;
+ /* XXX remove logspam */
+ debug2_f("constraint %zu %s%s%s (%u keys) > %s%s%s (%u keys)",
+ i, d->from.user ? d->from.user : "",
+ d->from.user ? "@" : "",
+ d->from.hostname ? d->from.hostname : "(ORIGIN)",
+ d->from.nkeys,
+ d->to.user ? d->to.user : "", d->to.user ? "@" : "",
+ d->to.hostname ? d->to.hostname : "(ANY)", d->to.nkeys);
+
+ /* Match 'from' key */
+ if (fromkey == NULL) {
+ /* We are matching the first hop */
+ if (d->from.hostname != NULL || d->from.nkeys != 0)
+ continue;
+ } else if (match_key_hop("from", fromkey, &d->from) != 0)
+ continue;
+
+ /* Match 'to' key */
+ if (tokey != NULL && match_key_hop("to", tokey, &d->to) != 0)
+ continue;
+
+ /* Match user if specified */
+ if (d->to.user != NULL && user != NULL &&
+ !match_pattern(user, d->to.user))
+ continue;
+
+ /* successfully matched this constraint */
+ if (hostnamep != NULL)
+ *hostnamep = d->to.hostname;
+ debug2_f("allowed for hostname %s",
+ d->to.hostname == NULL ? "*" : d->to.hostname);
+ return 0;
+ }
+ /* no match */
+ debug2_f("%s identity \"%s\" not permitted for this destination",
+ sshkey_type(id->key), id->comment);
+ return -1;
+}
+
+/*
+ * Check whether hostkeys on a SocketEntry and the optionally specified user
+ * are permitted by the destination constraints on the Identity.
+ * Returns 0 on success or -1 otherwise.
+ */
+static int
+identity_permitted(Identity *id, SocketEntry *e, char *user,
+ const char **forward_hostnamep, const char **last_hostnamep)
+{
+ size_t i;
+ const char **hp;
+ struct hostkey_sid *hks;
+ const struct sshkey *fromkey = NULL;
+ const char *test_user;
+ char *fp1, *fp2;
+
+ /* XXX remove logspam */
+ debug3_f("entering: key %s comment \"%s\", %zu socket bindings, "
+ "%zu constraints", sshkey_type(id->key), id->comment,
+ e->nsession_ids, id->ndest_constraints);
+ if (id->ndest_constraints == 0)
+ return 0; /* unconstrained */
+ if (e->nsession_ids == 0)
+ return 0; /* local use */
+ /*
+ * Walk through the hops recorded by session_id and try to find a
+ * constraint that satisfies each.
+ */
+ for (i = 0; i < e->nsession_ids; i++) {
+ hks = e->session_ids + i;
+ if (hks->key == NULL)
+ fatal_f("internal error: no bound key");
+ /* XXX remove logspam */
+ fp1 = fp2 = NULL;
+ if (fromkey != NULL &&
+ (fp1 = sshkey_fingerprint(fromkey, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ if ((fp2 = sshkey_fingerprint(hks->key, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug3_f("socketentry fd=%d, entry %zu %s, "
+ "from hostkey %s %s to user %s hostkey %s %s",
+ e->fd, i, hks->forwarded ? "FORWARD" : "AUTH",
+ fromkey ? sshkey_type(fromkey) : "(ORIGIN)",
+ fromkey ? fp1 : "", user ? user : "(ANY)",
+ sshkey_type(hks->key), fp2);
+ free(fp1);
+ free(fp2);
+ /*
+ * Record the hostnames for the initial forwarding and
+ * the final destination.
+ */
+ hp = NULL;
+ if (i == e->nsession_ids - 1)
+ hp = last_hostnamep;
+ else if (i == 0)
+ hp = forward_hostnamep;
+ /* Special handling for final recorded binding */
+ test_user = NULL;
+ if (i == e->nsession_ids - 1) {
+ /* Can only check user at final hop */
+ test_user = user;
+ /*
+ * user is only presented for signature requests.
+ * If this is the case, make sure last binding is not
+ * for a forwarding.
+ */
+ if (hks->forwarded && user != NULL) {
+ error_f("tried to sign on forwarding hop");
+ return -1;
+ }
+ } else if (!hks->forwarded) {
+ error_f("tried to forward though signing bind");
+ return -1;
+ }
+ if (permitted_by_dest_constraints(fromkey, hks->key, id,
+ test_user, hp) != 0)
+ return -1;
+ fromkey = hks->key;
+ }
+ /*
+ * Another special case: if the last bound session ID was for a
+ * forwarding, and this function is not being called to check a sign
+ * request (i.e. no 'user' supplied), then only permit the key if
+ * there is a permission that would allow it to be used at another
+ * destination. This hides keys that are allowed to be used to
+ * authenticate *to* a host but not permitted for *use* beyond it.
+ */
+ hks = &e->session_ids[e->nsession_ids - 1];
+ if (hks->forwarded && user == NULL &&
+ permitted_by_dest_constraints(hks->key, NULL, id,
+ NULL, NULL) != 0) {
+ debug3_f("key permitted at host but not after");
+ return -1;
+ }
+
+ /* success */
+ return 0;
+}
+
+/* return matching private key for given public key */
+static Identity *
+lookup_identity(struct sshkey *key)
+{
+ Identity *id;
+
+ TAILQ_FOREACH(id, &idtab->idlist, next) {
+ if (sshkey_equal(key, id->key))
+ return (id);
+ }
+ return (NULL);
+}
+
+/* Check confirmation of keysign request */
+static int
+confirm_key(Identity *id, const char *extra)
+{
+ char *p;
+ int ret = -1;
+
+ p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
+ if (p != NULL &&
+ ask_permission("Allow use of key %s?\nKey fingerprint %s.%s%s",
+ id->comment, p,
+ extra == NULL ? "" : "\n", extra == NULL ? "" : extra))
+ ret = 0;
+ free(p);
+
+ return (ret);
+}
+
+static void
+send_status(SocketEntry *e, int success)
+{
+ int r;
+
+ if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
+ (r = sshbuf_put_u8(e->output, success ?
+ SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
+ fatal_fr(r, "compose");
+}
+
+/* send list of supported public keys to 'client' */
+static void
+process_request_identities(SocketEntry *e)
+{
+ Identity *id;
+ struct sshbuf *msg, *keys;
+ int r;
+ u_int nentries = 0;
+
+ debug2_f("entering");
+
+ if ((msg = sshbuf_new()) == NULL || (keys = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ TAILQ_FOREACH(id, &idtab->idlist, next) {
+ /* identity not visible, don't include in response */
+ if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
+ continue;
+ if ((r = sshkey_puts_opts(id->key, keys,
+ SSHKEY_SERIALIZE_INFO)) != 0 ||
+ (r = sshbuf_put_cstring(keys, id->comment)) != 0) {
+ error_fr(r, "compose key/comment");
+ continue;
+ }
+ nentries++;
+ }
+ debug2_f("replying with %u allowed of %u available keys",
+ nentries, idtab->nentries);
+ if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
+ (r = sshbuf_put_u32(msg, nentries)) != 0 ||
+ (r = sshbuf_putb(msg, keys)) != 0)
+ fatal_fr(r, "compose");
+ if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
+ fatal_fr(r, "enqueue");
+ sshbuf_free(msg);
+ sshbuf_free(keys);
+}
+
+
+static char *
+agent_decode_alg(struct sshkey *key, u_int flags)
+{
+ if (key->type == KEY_RSA) {
+ if (flags & SSH_AGENT_RSA_SHA2_256)
+ return "rsa-sha2-256";
+ else if (flags & SSH_AGENT_RSA_SHA2_512)
+ return "rsa-sha2-512";
+ } else if (key->type == KEY_RSA_CERT) {
+ if (flags & SSH_AGENT_RSA_SHA2_256)
+ return "rsa-sha2-256-cert-v01@openssh.com";
+ else if (flags & SSH_AGENT_RSA_SHA2_512)
+ return "rsa-sha2-512-cert-v01@openssh.com";
+ }
+ return NULL;
+}
+
+/*
+ * Attempt to parse the contents of a buffer as a SSH publickey userauth
+ * request, checking its contents for consistency and matching the embedded
+ * key against the one that is being used for signing.
+ * Note: does not modify msg buffer.
+ * Optionally extract the username, session ID and/or hostkey from the request.
+ */
+static int
+parse_userauth_request(struct sshbuf *msg, const struct sshkey *expected_key,
+ char **userp, struct sshbuf **sess_idp, struct sshkey **hostkeyp)
+{
+ struct sshbuf *b = NULL, *sess_id = NULL;
+ char *user = NULL, *service = NULL, *method = NULL, *pkalg = NULL;
+ int r;
+ u_char t, sig_follows;
+ struct sshkey *mkey = NULL, *hostkey = NULL;
+
+ if (userp != NULL)
+ *userp = NULL;
+ if (sess_idp != NULL)
+ *sess_idp = NULL;
+ if (hostkeyp != NULL)
+ *hostkeyp = NULL;
+ if ((b = sshbuf_fromb(msg)) == NULL)
+ fatal_f("sshbuf_fromb");
+
+ /* SSH userauth request */
+ if ((r = sshbuf_froms(b, &sess_id)) != 0)
+ goto out;
+ if (sshbuf_len(sess_id) == 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if ((r = sshbuf_get_u8(b, &t)) != 0 || /* SSH2_MSG_USERAUTH_REQUEST */
+ (r = sshbuf_get_cstring(b, &user, NULL)) != 0 || /* server user */
+ (r = sshbuf_get_cstring(b, &service, NULL)) != 0 || /* service */
+ (r = sshbuf_get_cstring(b, &method, NULL)) != 0 || /* method */
+ (r = sshbuf_get_u8(b, &sig_follows)) != 0 || /* sig-follows */
+ (r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0 || /* alg */
+ (r = sshkey_froms(b, &mkey)) != 0) /* key */
+ goto out;
+ if (t != SSH2_MSG_USERAUTH_REQUEST ||
+ sig_follows != 1 ||
+ strcmp(service, "ssh-connection") != 0 ||
+ !sshkey_equal(expected_key, mkey) ||
+ sshkey_type_from_name(pkalg) != expected_key->type) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (strcmp(method, "publickey-hostbound-v00@openssh.com") == 0) {
+ if ((r = sshkey_froms(b, &hostkey)) != 0)
+ goto out;
+ } else if (strcmp(method, "publickey") != 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (sshbuf_len(b) != 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ /* success */
+ r = 0;
+ debug3_f("well formed userauth");
+ if (userp != NULL) {
+ *userp = user;
+ user = NULL;
+ }
+ if (sess_idp != NULL) {
+ *sess_idp = sess_id;
+ sess_id = NULL;
+ }
+ if (hostkeyp != NULL) {
+ *hostkeyp = hostkey;
+ hostkey = NULL;
+ }
+ out:
+ sshbuf_free(b);
+ sshbuf_free(sess_id);
+ free(user);
+ free(service);
+ free(method);
+ free(pkalg);
+ sshkey_free(mkey);
+ sshkey_free(hostkey);
+ return r;
+}
+
+/*
+ * Attempt to parse the contents of a buffer as a SSHSIG signature request.
+ * Note: does not modify buffer.
+ */
+static int
+parse_sshsig_request(struct sshbuf *msg)
+{
+ int r;
+ struct sshbuf *b;
+
+ if ((b = sshbuf_fromb(msg)) == NULL)
+ fatal_f("sshbuf_fromb");
+
+ if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) != 0 ||
+ (r = sshbuf_consume(b, 6)) != 0 ||
+ (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* namespace */
+ (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || /* reserved */
+ (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* hashalg */
+ (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0) /* H(msg) */
+ goto out;
+ if (sshbuf_len(b) != 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ /* success */
+ r = 0;
+ out:
+ sshbuf_free(b);
+ return r;
+}
+
+/*
+ * This function inspects a message to be signed by a FIDO key that has a
+ * web-like application string (i.e. one that does not begin with "ssh:".
+ * It checks that the message is one of those expected for SSH operations
+ * (pubkey userauth, sshsig, CA key signing) to exclude signing challenges
+ * for the web.
+ */
+static int
+check_websafe_message_contents(struct sshkey *key, struct sshbuf *data)
+{
+ if (parse_userauth_request(data, key, NULL, NULL, NULL) == 0) {
+ debug_f("signed data matches public key userauth request");
+ return 1;
+ }
+ if (parse_sshsig_request(data) == 0) {
+ debug_f("signed data matches SSHSIG signature request");
+ return 1;
+ }
+
+ /* XXX check CA signature operation */
+
+ error("web-origin key attempting to sign non-SSH message");
+ return 0;
+}
+
+static int
+buf_equal(const struct sshbuf *a, const struct sshbuf *b)
+{
+ if (sshbuf_ptr(a) == NULL || sshbuf_ptr(b) == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (sshbuf_len(a) != sshbuf_len(b))
+ return SSH_ERR_INVALID_FORMAT;
+ if (timingsafe_bcmp(sshbuf_ptr(a), sshbuf_ptr(b), sshbuf_len(a)) != 0)
+ return SSH_ERR_INVALID_FORMAT;
+ return 0;
+}
+
+/* ssh2 only */
+static void
+process_sign_request2(SocketEntry *e)
+{
+ u_char *signature = NULL;
+ size_t slen = 0;
+ u_int compat = 0, flags;
+ int r, ok = -1, retried = 0;
+ char *fp = NULL, *pin = NULL, *prompt = NULL;
+ char *user = NULL, *sig_dest = NULL;
+ const char *fwd_host = NULL, *dest_host = NULL;
+ struct sshbuf *msg = NULL, *data = NULL, *sid = NULL;
+ struct sshkey *key = NULL, *hostkey = NULL;
+ struct identity *id;
+ struct notifier_ctx *notifier = NULL;
+
+ debug_f("entering");
+
+ if ((msg = sshbuf_new()) == NULL || (data = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if ((r = sshkey_froms(e->request, &key)) != 0 ||
+ (r = sshbuf_get_stringb(e->request, data)) != 0 ||
+ (r = sshbuf_get_u32(e->request, &flags)) != 0) {
+ error_fr(r, "parse");
+ goto send;
+ }
+
+ if ((id = lookup_identity(key)) == NULL) {
+ verbose_f("%s key not found", sshkey_type(key));
+ goto send;
+ }
+ if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+
+ if (id->ndest_constraints != 0) {
+ if (e->nsession_ids == 0) {
+ logit_f("refusing use of destination-constrained key "
+ "to sign on unbound connection");
+ goto send;
+ }
+ if (parse_userauth_request(data, key, &user, &sid,
+ &hostkey) != 0) {
+ logit_f("refusing use of destination-constrained key "
+ "to sign an unidentified signature");
+ goto send;
+ }
+ /* XXX logspam */
+ debug_f("user=%s", user);
+ if (identity_permitted(id, e, user, &fwd_host, &dest_host) != 0)
+ goto send;
+ /* XXX display fwd_host/dest_host in askpass UI */
+ /*
+ * Ensure that the session ID is the most recent one
+ * registered on the socket - it should have been bound by
+ * ssh immediately before userauth.
+ */
+ if (buf_equal(sid,
+ e->session_ids[e->nsession_ids - 1].sid) != 0) {
+ error_f("unexpected session ID (%zu listed) on "
+ "signature request for target user %s with "
+ "key %s %s", e->nsession_ids, user,
+ sshkey_type(id->key), fp);
+ goto send;
+ }
+ /*
+ * Ensure that the hostkey embedded in the signature matches
+ * the one most recently bound to the socket. An exception is
+ * made for the initial forwarding hop.
+ */
+ if (e->nsession_ids > 1 && hostkey == NULL) {
+ error_f("refusing use of destination-constrained key: "
+ "no hostkey recorded in signature for forwarded "
+ "connection");
+ goto send;
+ }
+ if (hostkey != NULL && !sshkey_equal(hostkey,
+ e->session_ids[e->nsession_ids - 1].key)) {
+ error_f("refusing use of destination-constrained key: "
+ "mismatch between hostkey in request and most "
+ "recently bound session");
+ goto send;
+ }
+ xasprintf(&sig_dest, "public key authentication request for "
+ "user \"%s\" to listed host", user);
+ }
+ if (id->confirm && confirm_key(id, sig_dest) != 0) {
+ verbose_f("user refused key");
+ goto send;
+ }
+ if (sshkey_is_sk(id->key)) {
+ if (restrict_websafe &&
+ strncmp(id->key->sk_application, "ssh:", 4) != 0 &&
+ !check_websafe_message_contents(key, data)) {
+ /* error already logged */
+ goto send;
+ }
+ if (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) {
+ notifier = notify_start(0,
+ "Confirm user presence for key %s %s%s%s",
+ sshkey_type(id->key), fp,
+ sig_dest == NULL ? "" : "\n",
+ sig_dest == NULL ? "" : sig_dest);
+ }
+ }
+ retry_pin:
+ if ((r = sshkey_sign(id->key, &signature, &slen,
+ sshbuf_ptr(data), sshbuf_len(data), agent_decode_alg(key, flags),
+ id->sk_provider, pin, compat)) != 0) {
+ debug_fr(r, "sshkey_sign");
+ if (pin == NULL && !retried && sshkey_is_sk(id->key) &&
+ r == SSH_ERR_KEY_WRONG_PASSPHRASE) {
+ notify_complete(notifier, NULL);
+ notifier = NULL;
+ /* XXX include sig_dest */
+ xasprintf(&prompt, "Enter PIN%sfor %s key %s: ",
+ (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) ?
+ " and confirm user presence " : " ",
+ sshkey_type(id->key), fp);
+ pin = read_passphrase(prompt, RP_USE_ASKPASS);
+ retried = 1;
+ goto retry_pin;
+ }
+ error_fr(r, "sshkey_sign");
+ goto send;
+ }
+ /* Success */
+ ok = 0;
+ send:
+ debug_f("good signature");
+ notify_complete(notifier, "User presence confirmed");
+
+ if (ok == 0) {
+ if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
+ (r = sshbuf_put_string(msg, signature, slen)) != 0)
+ fatal_fr(r, "compose");
+ } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
+ fatal_fr(r, "compose failure");
+
+ if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
+ fatal_fr(r, "enqueue");
+
+ sshbuf_free(sid);
+ sshbuf_free(data);
+ sshbuf_free(msg);
+ sshkey_free(key);
+ sshkey_free(hostkey);
+ free(fp);
+ free(signature);
+ free(sig_dest);
+ free(user);
+ free(prompt);
+ if (pin != NULL)
+ freezero(pin, strlen(pin));
+}
+
+/* shared */
+static void
+process_remove_identity(SocketEntry *e)
+{
+ int r, success = 0;
+ struct sshkey *key = NULL;
+ Identity *id;
+
+ debug2_f("entering");
+ if ((r = sshkey_froms(e->request, &key)) != 0) {
+ error_fr(r, "parse key");
+ goto done;
+ }
+ if ((id = lookup_identity(key)) == NULL) {
+ debug_f("key not found");
+ goto done;
+ }
+ /* identity not visible, cannot be removed */
+ if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
+ goto done; /* error already logged */
+ /* We have this key, free it. */
+ if (idtab->nentries < 1)
+ fatal_f("internal error: nentries %d", idtab->nentries);
+ TAILQ_REMOVE(&idtab->idlist, id, next);
+ free_identity(id);
+ idtab->nentries--;
+ success = 1;
+ done:
+ sshkey_free(key);
+ send_status(e, success);
+}
+
+static void
+process_remove_all_identities(SocketEntry *e)
+{
+ Identity *id;
+
+ debug2_f("entering");
+ /* Loop over all identities and clear the keys. */
+ for (id = TAILQ_FIRST(&idtab->idlist); id;
+ id = TAILQ_FIRST(&idtab->idlist)) {
+ TAILQ_REMOVE(&idtab->idlist, id, next);
+ free_identity(id);
+ }
+
+ /* Mark that there are no identities. */
+ idtab->nentries = 0;
+
+ /* Send success. */
+ send_status(e, 1);
+}
+
+/* removes expired keys and returns number of seconds until the next expiry */
+static time_t
+reaper(void)
+{
+ time_t deadline = 0, now = monotime();
+ Identity *id, *nxt;
+
+ for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
+ nxt = TAILQ_NEXT(id, next);
+ if (id->death == 0)
+ continue;
+ if (now >= id->death) {
+ debug("expiring key '%s'", id->comment);
+ TAILQ_REMOVE(&idtab->idlist, id, next);
+ free_identity(id);
+ idtab->nentries--;
+ } else
+ deadline = (deadline == 0) ? id->death :
+ MINIMUM(deadline, id->death);
+ }
+ if (deadline == 0 || deadline <= now)
+ return 0;
+ else
+ return (deadline - now);
+}
+
+static int
+parse_dest_constraint_hop(struct sshbuf *b, struct dest_constraint_hop *dch)
+{
+ u_char key_is_ca;
+ size_t elen = 0;
+ int r;
+ struct sshkey *k = NULL;
+ char *fp;
+
+ memset(dch, '\0', sizeof(*dch));
+ if ((r = sshbuf_get_cstring(b, &dch->user, NULL)) != 0 ||
+ (r = sshbuf_get_cstring(b, &dch->hostname, NULL)) != 0 ||
+ (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) {
+ error_fr(r, "parse");
+ goto out;
+ }
+ if (elen != 0) {
+ error_f("unsupported extensions (len %zu)", elen);
+ r = SSH_ERR_FEATURE_UNSUPPORTED;
+ goto out;
+ }
+ if (*dch->hostname == '\0') {
+ free(dch->hostname);
+ dch->hostname = NULL;
+ }
+ if (*dch->user == '\0') {
+ free(dch->user);
+ dch->user = NULL;
+ }
+ while (sshbuf_len(b) != 0) {
+ 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_froms(b, &k)) != 0 ||
+ (r = sshbuf_get_u8(b, &key_is_ca)) != 0)
+ goto out;
+ if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug3_f("%s%s%s: adding %skey %s %s",
+ dch->user == NULL ? "" : dch->user,
+ dch->user == NULL ? "" : "@",
+ dch->hostname, key_is_ca ? "CA " : "", sshkey_type(k), fp);
+ free(fp);
+ dch->keys[dch->nkeys] = k;
+ dch->key_is_ca[dch->nkeys] = key_is_ca != 0;
+ dch->nkeys++;
+ k = NULL; /* transferred */
+ }
+ /* success */
+ r = 0;
+ out:
+ sshkey_free(k);
+ return r;
+}
+
+static int
+parse_dest_constraint(struct sshbuf *m, struct dest_constraint *dc)
+{
+ struct sshbuf *b = NULL, *frombuf = NULL, *tobuf = NULL;
+ int r;
+ size_t elen = 0;
+
+ debug3_f("entering");
+
+ memset(dc, '\0', sizeof(*dc));
+ if ((r = sshbuf_froms(m, &b)) != 0 ||
+ (r = sshbuf_froms(b, &frombuf)) != 0 ||
+ (r = sshbuf_froms(b, &tobuf)) != 0 ||
+ (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) {
+ error_fr(r, "parse");
+ goto out;
+ }
+ if ((r = parse_dest_constraint_hop(frombuf, &dc->from) != 0) ||
+ (r = parse_dest_constraint_hop(tobuf, &dc->to) != 0))
+ goto out; /* already logged */
+ if (elen != 0) {
+ error_f("unsupported extensions (len %zu)", elen);
+ r = SSH_ERR_FEATURE_UNSUPPORTED;
+ goto out;
+ }
+ debug2_f("parsed %s (%u keys) > %s%s%s (%u keys)",
+ 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);
+ /* check consistency */
+ if ((dc->from.hostname == NULL) != (dc->from.nkeys == 0) ||
+ dc->from.user != NULL) {
+ error_f("inconsistent \"from\" specification");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (dc->to.hostname == NULL || dc->to.nkeys == 0) {
+ error_f("incomplete \"to\" specification");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ /* success */
+ r = 0;
+ out:
+ sshbuf_free(b);
+ sshbuf_free(frombuf);
+ sshbuf_free(tobuf);
+ return r;
+}
+
+static int
+parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
+ struct dest_constraint **dcsp, size_t *ndcsp)
+{
+ char *ext_name = NULL;
+ int r;
+ struct sshbuf *b = NULL;
+
+ if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) {
+ error_fr(r, "parse constraint extension");
+ goto out;
+ }
+ debug_f("constraint ext %s", ext_name);
+ if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
+ if (sk_providerp == NULL) {
+ error_f("%s not valid here", ext_name);
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (*sk_providerp != NULL) {
+ error_f("%s already set", ext_name);
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) {
+ error_fr(r, "parse %s", ext_name);
+ goto out;
+ }
+ } else if (strcmp(ext_name,
+ "restrict-destination-v00@openssh.com") == 0) {
+ if (*dcsp != NULL) {
+ error_f("%s already set", ext_name);
+ goto out;
+ }
+ if ((r = sshbuf_froms(m, &b)) != 0) {
+ error_fr(r, "parse %s outer", ext_name);
+ goto out;
+ }
+ while (sshbuf_len(b) != 0) {
+ if (*ndcsp >= AGENT_MAX_DEST_CONSTRAINTS) {
+ error_f("too many %s constraints", ext_name);
+ goto out;
+ }
+ *dcsp = xrecallocarray(*dcsp, *ndcsp, *ndcsp + 1,
+ sizeof(**dcsp));
+ if ((r = parse_dest_constraint(b,
+ *dcsp + (*ndcsp)++)) != 0)
+ goto out; /* error already logged */
+ }
+ } else {
+ error_f("unsupported constraint \"%s\"", ext_name);
+ r = SSH_ERR_FEATURE_UNSUPPORTED;
+ goto out;
+ }
+ /* success */
+ r = 0;
+ out:
+ free(ext_name);
+ sshbuf_free(b);
+ return r;
+}
+
+static int
+parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
+ u_int *secondsp, int *confirmp, char **sk_providerp,
+ struct dest_constraint **dcsp, size_t *ndcsp)
+{
+ u_char ctype;
+ int r;
+ u_int seconds, maxsign = 0;
+
+ while (sshbuf_len(m)) {
+ if ((r = sshbuf_get_u8(m, &ctype)) != 0) {
+ error_fr(r, "parse constraint type");
+ goto out;
+ }
+ switch (ctype) {
+ case SSH_AGENT_CONSTRAIN_LIFETIME:
+ if (*deathp != 0) {
+ error_f("lifetime already set");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if ((r = sshbuf_get_u32(m, &seconds)) != 0) {
+ error_fr(r, "parse lifetime constraint");
+ goto out;
+ }
+ *deathp = monotime() + seconds;
+ *secondsp = seconds;
+ break;
+ case SSH_AGENT_CONSTRAIN_CONFIRM:
+ if (*confirmp != 0) {
+ error_f("confirm already set");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ *confirmp = 1;
+ break;
+ case SSH_AGENT_CONSTRAIN_MAXSIGN:
+ if (k == NULL) {
+ error_f("maxsign not valid here");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (maxsign != 0) {
+ error_f("maxsign already set");
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if ((r = sshbuf_get_u32(m, &maxsign)) != 0) {
+ error_fr(r, "parse maxsign constraint");
+ goto out;
+ }
+ if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
+ error_fr(r, "enable maxsign");
+ goto out;
+ }
+ break;
+ case SSH_AGENT_CONSTRAIN_EXTENSION:
+ if ((r = parse_key_constraint_extension(m,
+ sk_providerp, dcsp, ndcsp)) != 0)
+ goto out; /* error already logged */
+ break;
+ default:
+ error_f("Unknown constraint %d", ctype);
+ r = SSH_ERR_FEATURE_UNSUPPORTED;
+ goto out;
+ }
+ }
+ /* success */
+ r = 0;
+ out:
+ return r;
+}
+
+static void
+process_add_identity(SocketEntry *e)
+{
+ Identity *id;
+ int success = 0, confirm = 0;
+ char *fp, *comment = NULL, *sk_provider = NULL;
+ char canonical_provider[PATH_MAX];
+ time_t death = 0;
+ u_int seconds = 0;
+ struct dest_constraint *dest_constraints = NULL;
+ size_t ndest_constraints = 0;
+ struct sshkey *k = NULL;
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ debug2_f("entering");
+ if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
+ k == NULL ||
+ (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
+ error_fr(r, "parse");
+ goto out;
+ }
+ if (parse_key_constraints(e->request, k, &death, &seconds, &confirm,
+ &sk_provider, &dest_constraints, &ndest_constraints) != 0) {
+ error_f("failed to parse constraints");
+ sshbuf_reset(e->request);
+ goto out;
+ }
+
+ if (sk_provider != NULL) {
+ if (!sshkey_is_sk(k)) {
+ error("Cannot add provider: %s is not an "
+ "authenticator-hosted key", sshkey_type(k));
+ goto out;
+ }
+ if (strcasecmp(sk_provider, "internal") == 0) {
+ debug_f("internal provider");
+ } else {
+ if (realpath(sk_provider, canonical_provider) == NULL) {
+ verbose("failed provider \"%.100s\": "
+ "realpath: %s", sk_provider,
+ strerror(errno));
+ goto out;
+ }
+ free(sk_provider);
+ sk_provider = xstrdup(canonical_provider);
+ if (match_pattern_list(sk_provider,
+ allowed_providers, 0) != 1) {
+ error("Refusing add key: "
+ "provider %s not allowed", sk_provider);
+ goto out;
+ }
+ }
+ }
+ if ((r = sshkey_shield_private(k)) != 0) {
+ error_fr(r, "shield private");
+ goto out;
+ }
+ if (lifetime && !death)
+ death = monotime() + lifetime;
+ if ((id = lookup_identity(k)) == NULL) {
+ id = xcalloc(1, sizeof(Identity));
+ TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
+ /* Increment the number of identities. */
+ idtab->nentries++;
+ } else {
+ /* identity not visible, do not update */
+ if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
+ goto out; /* error already logged */
+ /* key state might have been updated */
+ sshkey_free(id->key);
+ free(id->comment);
+ free(id->sk_provider);
+ free_dest_constraints(id->dest_constraints,
+ id->ndest_constraints);
+ }
+ /* success */
+ id->key = k;
+ id->comment = comment;
+ id->death = death;
+ id->confirm = confirm;
+ id->sk_provider = sk_provider;
+ id->dest_constraints = dest_constraints;
+ id->ndest_constraints = ndest_constraints;
+
+ if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("sshkey_fingerprint failed");
+ debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) "
+ "(provider: %s) (destination constraints: %zu)",
+ sshkey_ssh_name(k), fp, comment, seconds, confirm,
+ sk_provider == NULL ? "none" : sk_provider, ndest_constraints);
+ free(fp);
+ /* transferred */
+ k = NULL;
+ comment = NULL;
+ sk_provider = NULL;
+ dest_constraints = NULL;
+ ndest_constraints = 0;
+ success = 1;
+ out:
+ free(sk_provider);
+ free(comment);
+ sshkey_free(k);
+ free_dest_constraints(dest_constraints, ndest_constraints);
+ send_status(e, success);
+}
+
+/* XXX todo: encrypt sensitive data with passphrase */
+static void
+process_lock_agent(SocketEntry *e, int lock)
+{
+ int r, success = 0, delay;
+ char *passwd;
+ u_char passwdhash[LOCK_SIZE];
+ static u_int fail_count = 0;
+ size_t pwlen;
+
+ debug2_f("entering");
+ /*
+ * This is deliberately fatal: the user has requested that we lock,
+ * but we can't parse their request properly. The only safe thing to
+ * do is abort.
+ */
+ if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
+ fatal_fr(r, "parse");
+ if (pwlen == 0) {
+ debug("empty password not supported");
+ } else if (locked && !lock) {
+ if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
+ passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
+ fatal("bcrypt_pbkdf");
+ if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
+ debug("agent unlocked");
+ locked = 0;
+ fail_count = 0;
+ explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
+ success = 1;
+ } else {
+ /* delay in 0.1s increments up to 10s */
+ if (fail_count < 100)
+ fail_count++;
+ delay = 100000 * fail_count;
+ debug("unlock failed, delaying %0.1lf seconds",
+ (double)delay/1000000);
+ usleep(delay);
+ }
+ explicit_bzero(passwdhash, sizeof(passwdhash));
+ } else if (!locked && lock) {
+ debug("agent locked");
+ locked = 1;
+ arc4random_buf(lock_salt, sizeof(lock_salt));
+ if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
+ lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
+ fatal("bcrypt_pbkdf");
+ success = 1;
+ }
+ freezero(passwd, pwlen);
+ send_status(e, success);
+}
+
+static void
+no_identities(SocketEntry *e)
+{
+ struct sshbuf *msg;
+ int r;
+
+ if ((msg = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
+ (r = sshbuf_put_u32(msg, 0)) != 0 ||
+ (r = sshbuf_put_stringb(e->output, msg)) != 0)
+ fatal_fr(r, "compose");
+ sshbuf_free(msg);
+}
+
+#ifdef ENABLE_PKCS11
+static void
+process_add_smartcard_key(SocketEntry *e)
+{
+ char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
+ char **comments = NULL;
+ int r, i, count = 0, success = 0, confirm = 0;
+ u_int seconds = 0;
+ time_t death = 0;
+ struct sshkey **keys = NULL, *k;
+ Identity *id;
+ struct dest_constraint *dest_constraints = NULL;
+ size_t ndest_constraints = 0;
+
+ debug2_f("entering");
+ if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
+ (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
+ error_fr(r, "parse");
+ goto send;
+ }
+ if (parse_key_constraints(e->request, NULL, &death, &seconds, &confirm,
+ NULL, &dest_constraints, &ndest_constraints) != 0) {
+ error_f("failed to parse constraints");
+ goto send;
+ }
+ if (realpath(provider, canonical_provider) == NULL) {
+ verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
+ provider, strerror(errno));
+ goto send;
+ }
+ if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) {
+ verbose("refusing PKCS#11 add of \"%.100s\": "
+ "provider not allowed", canonical_provider);
+ goto send;
+ }
+ debug_f("add %.100s", canonical_provider);
+ if (lifetime && !death)
+ death = monotime() + lifetime;
+
+ count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
+ for (i = 0; i < count; i++) {
+ k = keys[i];
+ if (lookup_identity(k) == NULL) {
+ id = xcalloc(1, sizeof(Identity));
+ id->key = k;
+ keys[i] = NULL; /* transferred */
+ id->provider = xstrdup(canonical_provider);
+ if (*comments[i] != '\0') {
+ id->comment = comments[i];
+ comments[i] = NULL; /* transferred */
+ } else {
+ id->comment = xstrdup(canonical_provider);
+ }
+ id->death = death;
+ id->confirm = confirm;
+ id->dest_constraints = dest_constraints;
+ id->ndest_constraints = ndest_constraints;
+ dest_constraints = NULL; /* transferred */
+ ndest_constraints = 0;
+ TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
+ idtab->nentries++;
+ success = 1;
+ }
+ /* XXX update constraints for existing keys */
+ sshkey_free(keys[i]);
+ free(comments[i]);
+ }
+send:
+ free(pin);
+ free(provider);
+ free(keys);
+ free(comments);
+ free_dest_constraints(dest_constraints, ndest_constraints);
+ send_status(e, success);
+}
+
+static void
+process_remove_smartcard_key(SocketEntry *e)
+{
+ char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
+ int r, success = 0;
+ Identity *id, *nxt;
+
+ debug2_f("entering");
+ if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
+ (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
+ error_fr(r, "parse");
+ goto send;
+ }
+ free(pin);
+
+ if (realpath(provider, canonical_provider) == NULL) {
+ verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
+ provider, strerror(errno));
+ goto send;
+ }
+
+ debug_f("remove %.100s", canonical_provider);
+ for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
+ nxt = TAILQ_NEXT(id, next);
+ /* Skip file--based keys */
+ if (id->provider == NULL)
+ continue;
+ if (!strcmp(canonical_provider, id->provider)) {
+ TAILQ_REMOVE(&idtab->idlist, id, next);
+ free_identity(id);
+ idtab->nentries--;
+ }
+ }
+ if (pkcs11_del_provider(canonical_provider) == 0)
+ success = 1;
+ else
+ error_f("pkcs11_del_provider failed");
+send:
+ free(provider);
+ send_status(e, success);
+}
+#endif /* ENABLE_PKCS11 */
+
+static int
+process_ext_session_bind(SocketEntry *e)
+{
+ int r, sid_match, key_match;
+ struct sshkey *key = NULL;
+ struct sshbuf *sid = NULL, *sig = NULL;
+ char *fp = NULL;
+ size_t i;
+ u_char fwd = 0;
+
+ debug2_f("entering");
+ if ((r = sshkey_froms(e->request, &key)) != 0 ||
+ (r = sshbuf_froms(e->request, &sid)) != 0 ||
+ (r = sshbuf_froms(e->request, &sig)) != 0 ||
+ (r = sshbuf_get_u8(e->request, &fwd)) != 0) {
+ error_fr(r, "parse");
+ goto out;
+ }
+ if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ /* check signature with hostkey on session ID */
+ if ((r = sshkey_verify(key, sshbuf_ptr(sig), sshbuf_len(sig),
+ sshbuf_ptr(sid), sshbuf_len(sid), NULL, 0, NULL)) != 0) {
+ error_fr(r, "sshkey_verify for %s %s", sshkey_type(key), fp);
+ goto out;
+ }
+ /* check whether sid/key already recorded */
+ for (i = 0; i < e->nsession_ids; i++) {
+ if (!e->session_ids[i].forwarded) {
+ error_f("attempt to bind session ID to socket "
+ "previously bound for authentication attempt");
+ r = -1;
+ goto out;
+ }
+ sid_match = buf_equal(sid, e->session_ids[i].sid) == 0;
+ key_match = sshkey_equal(key, e->session_ids[i].key);
+ if (sid_match && key_match) {
+ debug_f("session ID already recorded for %s %s",
+ sshkey_type(key), fp);
+ r = 0;
+ goto out;
+ } else if (sid_match) {
+ error_f("session ID recorded against different key "
+ "for %s %s", sshkey_type(key), fp);
+ r = -1;
+ goto out;
+ }
+ /*
+ * new sid with previously-seen key can happen, e.g. multiple
+ * connections to the same host.
+ */
+ }
+ /* record new key/sid */
+ if (e->nsession_ids >= AGENT_MAX_SESSION_IDS) {
+ error_f("too many session IDs recorded");
+ goto out;
+ }
+ e->session_ids = xrecallocarray(e->session_ids, e->nsession_ids,
+ e->nsession_ids + 1, sizeof(*e->session_ids));
+ i = e->nsession_ids++;
+ debug_f("recorded %s %s (slot %zu of %d)", sshkey_type(key), fp, i,
+ AGENT_MAX_SESSION_IDS);
+ e->session_ids[i].key = key;
+ e->session_ids[i].forwarded = fwd != 0;
+ key = NULL; /* transferred */
+ /* can't transfer sid; it's refcounted and scoped to request's life */
+ if ((e->session_ids[i].sid = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new");
+ if ((r = sshbuf_putb(e->session_ids[i].sid, sid)) != 0)
+ fatal_fr(r, "sshbuf_putb session ID");
+ /* success */
+ r = 0;
+ out:
+ free(fp);
+ sshkey_free(key);
+ sshbuf_free(sid);
+ sshbuf_free(sig);
+ return r == 0 ? 1 : 0;
+}
+
+static void
+process_extension(SocketEntry *e)
+{
+ int r, success = 0;
+ char *name;
+
+ debug2_f("entering");
+ if ((r = sshbuf_get_cstring(e->request, &name, NULL)) != 0) {
+ error_fr(r, "parse");
+ goto send;
+ }
+ if (strcmp(name, "session-bind@openssh.com") == 0)
+ success = process_ext_session_bind(e);
+ else
+ debug_f("unsupported extension \"%s\"", name);
+ free(name);
+send:
+ send_status(e, success);
+}
+/*
+ * dispatch incoming message.
+ * returns 1 on success, 0 for incomplete messages or -1 on error.
+ */
+static int
+process_message(u_int socknum)
+{
+ u_int msg_len;
+ u_char type;
+ const u_char *cp;
+ int r;
+ SocketEntry *e;
+
+ if (socknum >= sockets_alloc)
+ fatal_f("sock %u >= allocated %u", socknum, sockets_alloc);
+ e = &sockets[socknum];
+
+ if (sshbuf_len(e->input) < 5)
+ return 0; /* Incomplete message header. */
+ cp = sshbuf_ptr(e->input);
+ msg_len = PEEK_U32(cp);
+ if (msg_len > AGENT_MAX_LEN) {
+ debug_f("socket %u (fd=%d) message too long %u > %u",
+ socknum, e->fd, msg_len, AGENT_MAX_LEN);
+ return -1;
+ }
+ if (sshbuf_len(e->input) < msg_len + 4)
+ return 0; /* Incomplete message body. */
+
+ /* move the current input to e->request */
+ sshbuf_reset(e->request);
+ if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
+ (r = sshbuf_get_u8(e->request, &type)) != 0) {
+ if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
+ r == SSH_ERR_STRING_TOO_LARGE) {
+ error_fr(r, "parse");
+ return -1;
+ }
+ fatal_fr(r, "parse");
+ }
+
+ debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type);
+
+ /* check whether agent is locked */
+ if (locked && type != SSH_AGENTC_UNLOCK) {
+ sshbuf_reset(e->request);
+ switch (type) {
+ case SSH2_AGENTC_REQUEST_IDENTITIES:
+ /* send empty lists */
+ no_identities(e);
+ break;
+ default:
+ /* send a fail message for all other request types */
+ send_status(e, 0);
+ }
+ return 1;
+ }
+
+ switch (type) {
+ case SSH_AGENTC_LOCK:
+ case SSH_AGENTC_UNLOCK:
+ process_lock_agent(e, type == SSH_AGENTC_LOCK);
+ break;
+ case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
+ process_remove_all_identities(e); /* safe for !WITH_SSH1 */
+ break;
+ /* ssh2 */
+ case SSH2_AGENTC_SIGN_REQUEST:
+ process_sign_request2(e);
+ break;
+ case SSH2_AGENTC_REQUEST_IDENTITIES:
+ process_request_identities(e);
+ break;
+ case SSH2_AGENTC_ADD_IDENTITY:
+ case SSH2_AGENTC_ADD_ID_CONSTRAINED:
+ process_add_identity(e);
+ break;
+ case SSH2_AGENTC_REMOVE_IDENTITY:
+ process_remove_identity(e);
+ break;
+ case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
+ process_remove_all_identities(e);
+ break;
+#ifdef ENABLE_PKCS11
+ case SSH_AGENTC_ADD_SMARTCARD_KEY:
+ case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
+ process_add_smartcard_key(e);
+ break;
+ case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
+ process_remove_smartcard_key(e);
+ break;
+#endif /* ENABLE_PKCS11 */
+ case SSH_AGENTC_EXTENSION:
+ process_extension(e);
+ break;
+ default:
+ /* Unknown message. Respond with failure. */
+ error("Unknown message %d", type);
+ sshbuf_reset(e->request);
+ send_status(e, 0);
+ break;
+ }
+ return 1;
+}
+
+static void
+new_socket(sock_type type, int fd)
+{
+ u_int i, old_alloc, new_alloc;
+
+ debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" :
+ (type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN"));
+ set_nonblock(fd);
+
+ if (fd > max_fd)
+ max_fd = fd;
+
+ for (i = 0; i < sockets_alloc; i++)
+ if (sockets[i].type == AUTH_UNUSED) {
+ sockets[i].fd = fd;
+ if ((sockets[i].input = sshbuf_new()) == NULL ||
+ (sockets[i].output = sshbuf_new()) == NULL ||
+ (sockets[i].request = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ sockets[i].type = type;
+ return;
+ }
+ old_alloc = sockets_alloc;
+ new_alloc = sockets_alloc + 10;
+ sockets = xrecallocarray(sockets, old_alloc, new_alloc,
+ sizeof(sockets[0]));
+ for (i = old_alloc; i < new_alloc; i++)
+ sockets[i].type = AUTH_UNUSED;
+ sockets_alloc = new_alloc;
+ sockets[old_alloc].fd = fd;
+ if ((sockets[old_alloc].input = sshbuf_new()) == NULL ||
+ (sockets[old_alloc].output = sshbuf_new()) == NULL ||
+ (sockets[old_alloc].request = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ sockets[old_alloc].type = type;
+}
+
+static int
+handle_socket_read(u_int socknum)
+{
+ struct sockaddr_un sunaddr;
+ socklen_t slen;
+ uid_t euid;
+ gid_t egid;
+ int fd;
+
+ slen = sizeof(sunaddr);
+ fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
+ if (fd == -1) {
+ error("accept from AUTH_SOCKET: %s", strerror(errno));
+ return -1;
+ }
+ if (getpeereid(fd, &euid, &egid) == -1) {
+ error("getpeereid %d failed: %s", fd, strerror(errno));
+ close(fd);
+ return -1;
+ }
+ if ((euid != 0) && (getuid() != euid)) {
+ error("uid mismatch: peer euid %u != uid %u",
+ (u_int) euid, (u_int) getuid());
+ close(fd);
+ return -1;
+ }
+ new_socket(AUTH_CONNECTION, fd);
+ return 0;
+}
+
+static int
+handle_conn_read(u_int socknum)
+{
+ char buf[AGENT_RBUF_LEN];
+ ssize_t len;
+ int r;
+
+ if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
+ if (len == -1) {
+ if (errno == EAGAIN || errno == EINTR)
+ return 0;
+ error_f("read error on socket %u (fd %d): %s",
+ socknum, sockets[socknum].fd, strerror(errno));
+ }
+ return -1;
+ }
+ if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
+ fatal_fr(r, "compose");
+ explicit_bzero(buf, sizeof(buf));
+ for (;;) {
+ if ((r = process_message(socknum)) == -1)
+ return -1;
+ else if (r == 0)
+ break;
+ }
+ return 0;
+}
+
+static int
+handle_conn_write(u_int socknum)
+{
+ ssize_t len;
+ int r;
+
+ if (sshbuf_len(sockets[socknum].output) == 0)
+ return 0; /* shouldn't happen */
+ if ((len = write(sockets[socknum].fd,
+ sshbuf_ptr(sockets[socknum].output),
+ sshbuf_len(sockets[socknum].output))) <= 0) {
+ if (len == -1) {
+ if (errno == EAGAIN || errno == EINTR)
+ return 0;
+ error_f("read error on socket %u (fd %d): %s",
+ socknum, sockets[socknum].fd, strerror(errno));
+ }
+ return -1;
+ }
+ if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
+ fatal_fr(r, "consume");
+ return 0;
+}
+
+static void
+after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
+{
+ size_t i;
+ u_int socknum, activefds = npfd;
+
+ for (i = 0; i < npfd; i++) {
+ if (pfd[i].revents == 0)
+ continue;
+ /* Find sockets entry */
+ for (socknum = 0; socknum < sockets_alloc; socknum++) {
+ if (sockets[socknum].type != AUTH_SOCKET &&
+ sockets[socknum].type != AUTH_CONNECTION)
+ continue;
+ if (pfd[i].fd == sockets[socknum].fd)
+ break;
+ }
+ if (socknum >= sockets_alloc) {
+ error_f("no socket for fd %d", pfd[i].fd);
+ continue;
+ }
+ /* Process events */
+ switch (sockets[socknum].type) {
+ case AUTH_SOCKET:
+ if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
+ break;
+ if (npfd > maxfds) {
+ debug3("out of fds (active %u >= limit %u); "
+ "skipping accept", activefds, maxfds);
+ break;
+ }
+ if (handle_socket_read(socknum) == 0)
+ activefds++;
+ break;
+ case AUTH_CONNECTION:
+ if ((pfd[i].revents & (POLLIN|POLLHUP|POLLERR)) != 0 &&
+ handle_conn_read(socknum) != 0)
+ goto close_sock;
+ if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
+ handle_conn_write(socknum) != 0) {
+ close_sock:
+ if (activefds == 0)
+ fatal("activefds == 0 at close_sock");
+ close_socket(&sockets[socknum]);
+ activefds--;
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+}
+
+static int
+prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
+{
+ struct pollfd *pfd = *pfdp;
+ size_t i, j, npfd = 0;
+ time_t deadline;
+ int r;
+
+ /* Count active sockets */
+ for (i = 0; i < sockets_alloc; i++) {
+ switch (sockets[i].type) {
+ case AUTH_SOCKET:
+ case AUTH_CONNECTION:
+ npfd++;
+ break;
+ case AUTH_UNUSED:
+ break;
+ default:
+ fatal("Unknown socket type %d", sockets[i].type);
+ break;
+ }
+ }
+ if (npfd != *npfdp &&
+ (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
+ fatal_f("recallocarray failed");
+ *pfdp = pfd;
+ *npfdp = npfd;
+
+ for (i = j = 0; i < sockets_alloc; i++) {
+ switch (sockets[i].type) {
+ case AUTH_SOCKET:
+ if (npfd > maxfds) {
+ debug3("out of fds (active %zu >= limit %u); "
+ "skipping arming listener", npfd, maxfds);
+ break;
+ }
+ pfd[j].fd = sockets[i].fd;
+ pfd[j].revents = 0;
+ pfd[j].events = POLLIN;
+ j++;
+ break;
+ case AUTH_CONNECTION:
+ pfd[j].fd = sockets[i].fd;
+ pfd[j].revents = 0;
+ /*
+ * Only prepare to read if we can handle a full-size
+ * input read buffer and enqueue a max size reply..
+ */
+ if ((r = sshbuf_check_reserve(sockets[i].input,
+ AGENT_RBUF_LEN)) == 0 &&
+ (r = sshbuf_check_reserve(sockets[i].output,
+ AGENT_MAX_LEN)) == 0)
+ pfd[j].events = POLLIN;
+ else if (r != SSH_ERR_NO_BUFFER_SPACE)
+ fatal_fr(r, "reserve");
+ if (sshbuf_len(sockets[i].output) > 0)
+ pfd[j].events |= POLLOUT;
+ j++;
+ break;
+ default:
+ break;
+ }
+ }
+ deadline = reaper();
+ if (parent_alive_interval != 0)
+ deadline = (deadline == 0) ? parent_alive_interval :
+ MINIMUM(deadline, parent_alive_interval);
+ if (deadline == 0) {
+ *timeoutp = -1; /* INFTIM */
+ } else {
+ if (deadline > INT_MAX / 1000)
+ *timeoutp = INT_MAX / 1000;
+ else
+ *timeoutp = deadline * 1000;
+ }
+ return (1);
+}
+
+static void
+cleanup_socket(void)
+{
+ if (cleanup_pid != 0 && getpid() != cleanup_pid)
+ return;
+ debug_f("cleanup");
+ if (socket_name[0])
+ unlink(socket_name);
+ if (socket_dir[0])
+ rmdir(socket_dir);
+}
+
+void
+cleanup_exit(int i)
+{
+ cleanup_socket();
+ _exit(i);
+}
+
+/*ARGSUSED*/
+static void
+cleanup_handler(int sig)
+{
+ cleanup_socket();
+#ifdef ENABLE_PKCS11
+ pkcs11_terminate();
+#endif
+ _exit(2);
+}
+
+static void
+check_parent_exists(void)
+{
+ /*
+ * If our parent has exited then getppid() will return (pid_t)1,
+ * so testing for that should be safe.
+ */
+ if (parent_pid != -1 && getppid() != parent_pid) {
+ /* printf("Parent has died - Authentication agent exiting.\n"); */
+ cleanup_socket();
+ _exit(2);
+ }
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr,
+ "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
+ " [-O option] [-P allowed_providers] [-t life]\n"
+ " ssh-agent [-a bind_address] [-E fingerprint_hash] [-O option]\n"
+ " [-P allowed_providers] [-t life] command [arg ...]\n"
+ " ssh-agent [-c | -s] -k\n");
+ exit(1);
+}
+
+int
+main(int ac, char **av)
+{
+ int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
+ int sock, ch, result, saved_errno;
+ char *shell, *format, *pidstr, *agentsocket = NULL;
+#ifdef HAVE_SETRLIMIT
+ struct rlimit rlim;
+#endif
+ extern int optind;
+ extern char *optarg;
+ pid_t pid;
+ char pidstrbuf[1 + 3 * sizeof pid];
+ size_t len;
+ mode_t prev_mask;
+ int timeout = -1; /* INFTIM */
+ struct pollfd *pfd = NULL;
+ size_t npfd = 0;
+ u_int maxfds;
+
+ /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+ sanitise_stdfd();
+
+ /* drop */
+ setegid(getgid());
+ setgid(getgid());
+
+ platform_disable_tracing(0); /* strict=no */
+
+#ifdef RLIMIT_NOFILE
+ if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
+ fatal("%s: getrlimit: %s", __progname, strerror(errno));
+#endif
+
+ __progname = ssh_get_progname(av[0]);
+ seed_rng();
+
+ while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:")) != -1) {
+ switch (ch) {
+ case 'E':
+ fingerprint_hash = ssh_digest_alg_by_name(optarg);
+ if (fingerprint_hash == -1)
+ fatal("Invalid hash algorithm \"%s\"", optarg);
+ break;
+ case 'c':
+ if (s_flag)
+ usage();
+ c_flag++;
+ break;
+ case 'k':
+ k_flag++;
+ break;
+ case 'O':
+ if (strcmp(optarg, "no-restrict-websafe") == 0)
+ restrict_websafe = 0;
+ else
+ fatal("Unknown -O option");
+ break;
+ case 'P':
+ if (allowed_providers != NULL)
+ fatal("-P option already specified");
+ allowed_providers = xstrdup(optarg);
+ break;
+ case 's':
+ if (c_flag)
+ usage();
+ s_flag++;
+ break;
+ case 'd':
+ if (d_flag || D_flag)
+ usage();
+ d_flag++;
+ break;
+ case 'D':
+ if (d_flag || D_flag)
+ usage();
+ D_flag++;
+ break;
+ case 'a':
+ agentsocket = optarg;
+ break;
+ case 't':
+ if ((lifetime = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid lifetime\n");
+ usage();
+ }
+ break;
+ default:
+ usage();
+ }
+ }
+ ac -= optind;
+ av += optind;
+
+ if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
+ usage();
+
+ if (allowed_providers == NULL)
+ allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS);
+
+ if (ac == 0 && !c_flag && !s_flag) {
+ shell = getenv("SHELL");
+ if (shell != NULL && (len = strlen(shell)) > 2 &&
+ strncmp(shell + len - 3, "csh", 3) == 0)
+ c_flag = 1;
+ }
+ if (k_flag) {
+ const char *errstr = NULL;
+
+ pidstr = getenv(SSH_AGENTPID_ENV_NAME);
+ if (pidstr == NULL) {
+ fprintf(stderr, "%s not set, cannot kill agent\n",
+ SSH_AGENTPID_ENV_NAME);
+ exit(1);
+ }
+ pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
+ if (errstr) {
+ fprintf(stderr,
+ "%s=\"%s\", which is not a good PID: %s\n",
+ SSH_AGENTPID_ENV_NAME, pidstr, errstr);
+ exit(1);
+ }
+ if (kill(pid, SIGTERM) == -1) {
+ perror("kill");
+ exit(1);
+ }
+ format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
+ printf(format, SSH_AUTHSOCKET_ENV_NAME);
+ printf(format, SSH_AGENTPID_ENV_NAME);
+ printf("echo Agent pid %ld killed;\n", (long)pid);
+ exit(0);
+ }
+
+ /*
+ * Minimum file descriptors:
+ * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
+ * a few spare for libc / stack protectors / sanitisers, etc.
+ */
+#define SSH_AGENT_MIN_FDS (3+1+1+1+4)
+ if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
+ fatal("%s: file descriptor rlimit %lld too low (minimum %u)",
+ __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
+ maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
+
+ parent_pid = getpid();
+
+ if (agentsocket == NULL) {
+ /* Create private directory for agent socket */
+ mktemp_proto(socket_dir, sizeof(socket_dir));
+ if (mkdtemp(socket_dir) == NULL) {
+ perror("mkdtemp: private socket dir");
+ exit(1);
+ }
+ snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
+ (long)parent_pid);
+ } else {
+ /* Try to use specified agent socket */
+ socket_dir[0] = '\0';
+ strlcpy(socket_name, agentsocket, sizeof socket_name);
+ }
+
+ /*
+ * Create socket early so it will exist before command gets run from
+ * the parent.
+ */
+ prev_mask = umask(0177);
+ sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
+ if (sock < 0) {
+ /* XXX - unix_listener() calls error() not perror() */
+ *socket_name = '\0'; /* Don't unlink any existing file */
+ cleanup_exit(1);
+ }
+ umask(prev_mask);
+
+ /*
+ * Fork, and have the parent execute the command, if any, or present
+ * the socket data. The child continues as the authentication agent.
+ */
+ if (D_flag || d_flag) {
+ log_init(__progname,
+ d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
+ SYSLOG_FACILITY_AUTH, 1);
+ format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
+ printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
+ SSH_AUTHSOCKET_ENV_NAME);
+ printf("echo Agent pid %ld;\n", (long)parent_pid);
+ fflush(stdout);
+ goto skip;
+ }
+ pid = fork();
+ if (pid == -1) {
+ perror("fork");
+ cleanup_exit(1);
+ }
+ if (pid != 0) { /* Parent - execute the given command. */
+ close(sock);
+ snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
+ if (ac == 0) {
+ format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
+ printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
+ SSH_AUTHSOCKET_ENV_NAME);
+ printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
+ SSH_AGENTPID_ENV_NAME);
+ printf("echo Agent pid %ld;\n", (long)pid);
+ exit(0);
+ }
+ if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
+ setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
+ perror("setenv");
+ exit(1);
+ }
+ execvp(av[0], av);
+ perror(av[0]);
+ exit(1);
+ }
+ /* child */
+ log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
+
+ if (setsid() == -1) {
+ error("setsid: %s", strerror(errno));
+ cleanup_exit(1);
+ }
+
+ (void)chdir("/");
+ if (stdfd_devnull(1, 1, 1) == -1)
+ error_f("stdfd_devnull failed");
+
+#ifdef HAVE_SETRLIMIT
+ /* deny core dumps, since memory contains unencrypted private keys */
+ rlim.rlim_cur = rlim.rlim_max = 0;
+ if (setrlimit(RLIMIT_CORE, &rlim) == -1) {
+ error("setrlimit RLIMIT_CORE: %s", strerror(errno));
+ cleanup_exit(1);
+ }
+#endif
+
+skip:
+
+ cleanup_pid = getpid();
+
+#ifdef ENABLE_PKCS11
+ pkcs11_init(0);
+#endif
+ new_socket(AUTH_SOCKET, sock);
+ if (ac > 0)
+ parent_alive_interval = 10;
+ idtab_init();
+ ssh_signal(SIGPIPE, SIG_IGN);
+ ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
+ ssh_signal(SIGHUP, cleanup_handler);
+ ssh_signal(SIGTERM, cleanup_handler);
+
+ if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
+ fatal("%s: pledge: %s", __progname, strerror(errno));
+ platform_pledge_agent();
+
+ while (1) {
+ prepare_poll(&pfd, &npfd, &timeout, maxfds);
+ result = poll(pfd, npfd, timeout);
+ saved_errno = errno;
+ if (parent_alive_interval != 0)
+ check_parent_exists();
+ (void) reaper(); /* remove expired keys */
+ if (result == -1) {
+ if (saved_errno == EINTR)
+ continue;
+ fatal("poll: %s", strerror(saved_errno));
+ } else if (result > 0)
+ after_poll(pfd, npfd, maxfds);
+ }
+ /* NOTREACHED */
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 07:00:12 +0000