|
- /* $OpenBSD: auth.c,v 1.160 2023/03/05 05:34:09 dtucker Exp $ */
- /*
- * Copyright (c) 2000 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>
- #include <sys/socket.h>
- #include <sys/wait.h>
-
- #include <netinet/in.h>
-
- #include <stdlib.h>
- #include <errno.h>
- #include <fcntl.h>
- #ifdef HAVE_PATHS_H
- # include <paths.h>
- #endif
- #include <pwd.h>
- #ifdef HAVE_LOGIN_H
- #include <login.h>
- #endif
- #ifdef USE_SHADOW
- #include <shadow.h>
- #endif
- #include <stdarg.h>
- #include <stdio.h>
- #include <string.h>
- #include <unistd.h>
- #include <limits.h>
- #include <netdb.h>
- #include <time.h>
-
- #include "xmalloc.h"
- #include "match.h"
- #include "groupaccess.h"
- #include "log.h"
- #include "sshbuf.h"
- #include "misc.h"
- #include "servconf.h"
- #include "sshkey.h"
- #include "hostfile.h"
- #include "auth.h"
- #include "auth-options.h"
- #include "canohost.h"
- #include "uidswap.h"
- #include "packet.h"
- #include "loginrec.h"
- #ifdef GSSAPI
- #include "ssh-gss.h"
- #endif
- #include "authfile.h"
- #include "monitor_wrap.h"
- #include "ssherr.h"
- #include "channels.h"
-
- /* import */
- extern ServerOptions options;
- extern struct include_list includes;
- extern int use_privsep;
- extern struct sshbuf *loginmsg;
- extern struct passwd *privsep_pw;
- extern struct sshauthopt *auth_opts;
-
- /* Debugging messages */
- static struct sshbuf *auth_debug;
-
- /*
- * Check if the user is allowed to log in via ssh. If user is listed
- * in DenyUsers or one of user's groups is listed in DenyGroups, false
- * will be returned. If AllowUsers isn't empty and user isn't listed
- * there, or if AllowGroups isn't empty and one of user's groups isn't
- * listed there, false will be returned.
- * If the user's shell is not executable, false will be returned.
- * Otherwise true is returned.
- */
- int
- allowed_user(struct ssh *ssh, struct passwd * pw)
- {
- struct stat st;
- const char *hostname = NULL, *ipaddr = NULL;
- u_int i;
- int r;
-
- /* Shouldn't be called if pw is NULL, but better safe than sorry... */
- if (!pw || !pw->pw_name)
- return 0;
-
- if (!options.use_pam && platform_locked_account(pw)) {
- logit("User %.100s not allowed because account is locked",
- pw->pw_name);
- return 0;
- }
-
- /*
- * Deny if shell does not exist or is not executable unless we
- * are chrooting.
- */
- if (options.chroot_directory == NULL ||
- strcasecmp(options.chroot_directory, "none") == 0) {
- char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
- _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
-
- if (stat(shell, &st) == -1) {
- logit("User %.100s not allowed because shell %.100s "
- "does not exist", pw->pw_name, shell);
- free(shell);
- return 0;
- }
- if (S_ISREG(st.st_mode) == 0 ||
- (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
- logit("User %.100s not allowed because shell %.100s "
- "is not executable", pw->pw_name, shell);
- free(shell);
- return 0;
- }
- free(shell);
- }
-
- if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
- options.num_deny_groups > 0 || options.num_allow_groups > 0) {
- hostname = auth_get_canonical_hostname(ssh, options.use_dns);
- ipaddr = ssh_remote_ipaddr(ssh);
- }
-
- /* Return false if user is listed in DenyUsers */
- if (options.num_deny_users > 0) {
- for (i = 0; i < options.num_deny_users; i++) {
- r = match_user(pw->pw_name, hostname, ipaddr,
- options.deny_users[i]);
- if (r < 0) {
- fatal("Invalid DenyUsers pattern \"%.100s\"",
- options.deny_users[i]);
- } else if (r != 0) {
- logit("User %.100s from %.100s not allowed "
- "because listed in DenyUsers",
- pw->pw_name, hostname);
- return 0;
- }
- }
- }
- /* Return false if AllowUsers isn't empty and user isn't listed there */
- if (options.num_allow_users > 0) {
- for (i = 0; i < options.num_allow_users; i++) {
- r = match_user(pw->pw_name, hostname, ipaddr,
- options.allow_users[i]);
- if (r < 0) {
- fatal("Invalid AllowUsers pattern \"%.100s\"",
- options.allow_users[i]);
- } else if (r == 1)
- break;
- }
- /* i < options.num_allow_users iff we break for loop */
- if (i >= options.num_allow_users) {
- logit("User %.100s from %.100s not allowed because "
- "not listed in AllowUsers", pw->pw_name, hostname);
- return 0;
- }
- }
- if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
- /* Get the user's group access list (primary and supplementary) */
- if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
- logit("User %.100s from %.100s not allowed because "
- "not in any group", pw->pw_name, hostname);
- return 0;
- }
-
- /* Return false if one of user's groups is listed in DenyGroups */
- if (options.num_deny_groups > 0)
- if (ga_match(options.deny_groups,
- options.num_deny_groups)) {
- ga_free();
- logit("User %.100s from %.100s not allowed "
- "because a group is listed in DenyGroups",
- pw->pw_name, hostname);
- return 0;
- }
- /*
- * Return false if AllowGroups isn't empty and one of user's groups
- * isn't listed there
- */
- if (options.num_allow_groups > 0)
- if (!ga_match(options.allow_groups,
- options.num_allow_groups)) {
- ga_free();
- logit("User %.100s from %.100s not allowed "
- "because none of user's groups are listed "
- "in AllowGroups", pw->pw_name, hostname);
- return 0;
- }
- ga_free();
- }
-
- #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
- if (!sys_auth_allowed_user(pw, loginmsg))
- return 0;
- #endif
-
- /* We found no reason not to let this user try to log on... */
- return 1;
- }
-
- /*
- * Formats any key left in authctxt->auth_method_key for inclusion in
- * auth_log()'s message. Also includes authxtct->auth_method_info if present.
- */
- static char *
- format_method_key(Authctxt *authctxt)
- {
- const struct sshkey *key = authctxt->auth_method_key;
- const char *methinfo = authctxt->auth_method_info;
- char *fp, *cafp, *ret = NULL;
-
- if (key == NULL)
- return NULL;
-
- if (sshkey_is_cert(key)) {
- fp = sshkey_fingerprint(key,
- options.fingerprint_hash, SSH_FP_DEFAULT);
- cafp = sshkey_fingerprint(key->cert->signature_key,
- options.fingerprint_hash, SSH_FP_DEFAULT);
- xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s",
- sshkey_type(key), fp == NULL ? "(null)" : fp,
- key->cert->key_id,
- (unsigned long long)key->cert->serial,
- sshkey_type(key->cert->signature_key),
- cafp == NULL ? "(null)" : cafp,
- methinfo == NULL ? "" : ", ",
- methinfo == NULL ? "" : methinfo);
- free(fp);
- free(cafp);
- } else {
- fp = sshkey_fingerprint(key, options.fingerprint_hash,
- SSH_FP_DEFAULT);
- xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
- fp == NULL ? "(null)" : fp,
- methinfo == NULL ? "" : ", ",
- methinfo == NULL ? "" : methinfo);
- free(fp);
- }
- return ret;
- }
-
- void
- auth_log(struct ssh *ssh, int authenticated, int partial,
- const char *method, const char *submethod)
- {
- Authctxt *authctxt = (Authctxt *)ssh->authctxt;
- int level = SYSLOG_LEVEL_VERBOSE;
- const char *authmsg;
- char *extra = NULL;
-
- if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
- return;
-
- /* Raise logging level */
- if (authenticated == 1 ||
- !authctxt->valid ||
- authctxt->failures >= options.max_authtries / 2 ||
- strcmp(method, "password") == 0)
- level = SYSLOG_LEVEL_INFO;
-
- if (authctxt->postponed)
- authmsg = "Postponed";
- else if (partial)
- authmsg = "Partial";
- else
- authmsg = authenticated ? "Accepted" : "Failed";
-
- if ((extra = format_method_key(authctxt)) == NULL) {
- if (authctxt->auth_method_info != NULL)
- extra = xstrdup(authctxt->auth_method_info);
- }
-
- do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
- authmsg,
- method,
- submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
- authctxt->valid ? "" : "invalid user ",
- authctxt->user,
- ssh_remote_ipaddr(ssh),
- ssh_remote_port(ssh),
- extra != NULL ? ": " : "",
- extra != NULL ? extra : "");
-
- free(extra);
-
- #if defined(CUSTOM_FAILED_LOGIN) || defined(SSH_AUDIT_EVENTS)
- if (authenticated == 0 && !(authctxt->postponed || partial)) {
- /* Log failed login attempt */
- # ifdef CUSTOM_FAILED_LOGIN
- if (strcmp(method, "password") == 0 ||
- strncmp(method, "keyboard-interactive", 20) == 0 ||
- strcmp(method, "challenge-response") == 0)
- record_failed_login(ssh, authctxt->user,
- auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
- # endif
- # ifdef SSH_AUDIT_EVENTS
- audit_event(ssh, audit_classify_auth(method));
- # endif
- }
- #endif
- #if defined(CUSTOM_FAILED_LOGIN) && defined(WITH_AIXAUTHENTICATE)
- if (authenticated)
- sys_auth_record_login(authctxt->user,
- auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
- loginmsg);
- #endif
- }
-
- void
- auth_maxtries_exceeded(struct ssh *ssh)
- {
- Authctxt *authctxt = (Authctxt *)ssh->authctxt;
-
- error("maximum authentication attempts exceeded for "
- "%s%.100s from %.200s port %d ssh2",
- authctxt->valid ? "" : "invalid user ",
- authctxt->user,
- ssh_remote_ipaddr(ssh),
- ssh_remote_port(ssh));
- ssh_packet_disconnect(ssh, "Too many authentication failures");
- /* NOTREACHED */
- }
-
- /*
- * Check whether root logins are disallowed.
- */
- int
- auth_root_allowed(struct ssh *ssh, const char *method)
- {
- switch (options.permit_root_login) {
- case PERMIT_YES:
- return 1;
- case PERMIT_NO_PASSWD:
- if (strcmp(method, "publickey") == 0 ||
- strcmp(method, "hostbased") == 0 ||
- strcmp(method, "gssapi-with-mic") == 0)
- return 1;
- break;
- case PERMIT_FORCED_ONLY:
- if (auth_opts->force_command != NULL) {
- logit("Root login accepted for forced command.");
- return 1;
- }
- break;
- }
- logit("ROOT LOGIN REFUSED FROM %.200s port %d",
- ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
- return 0;
- }
-
-
- /*
- * Given a template and a passwd structure, build a filename
- * by substituting % tokenised options. Currently, %% becomes '%',
- * %h becomes the home directory and %u the username.
- *
- * This returns a buffer allocated by xmalloc.
- */
- char *
- expand_authorized_keys(const char *filename, struct passwd *pw)
- {
- char *file, uidstr[32], ret[PATH_MAX];
- int i;
-
- snprintf(uidstr, sizeof(uidstr), "%llu",
- (unsigned long long)pw->pw_uid);
- file = percent_expand(filename, "h", pw->pw_dir,
- "u", pw->pw_name, "U", uidstr, (char *)NULL);
-
- /*
- * Ensure that filename starts anchored. If not, be backward
- * compatible and prepend the '%h/'
- */
- if (path_absolute(file))
- return (file);
-
- i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
- if (i < 0 || (size_t)i >= sizeof(ret))
- fatal("expand_authorized_keys: path too long");
- free(file);
- return (xstrdup(ret));
- }
-
- char *
- authorized_principals_file(struct passwd *pw)
- {
- if (options.authorized_principals_file == NULL)
- return NULL;
- return expand_authorized_keys(options.authorized_principals_file, pw);
- }
-
- /* return ok if key exists in sysfile or userfile */
- HostStatus
- check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
- const char *sysfile, const char *userfile)
- {
- char *user_hostfile;
- struct stat st;
- HostStatus host_status;
- struct hostkeys *hostkeys;
- const struct hostkey_entry *found;
-
- hostkeys = init_hostkeys();
- load_hostkeys(hostkeys, host, sysfile, 0);
- if (userfile != NULL) {
- user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
- if (options.strict_modes &&
- (stat(user_hostfile, &st) == 0) &&
- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
- (st.st_mode & 022) != 0)) {
- logit("Authentication refused for %.100s: "
- "bad owner or modes for %.200s",
- pw->pw_name, user_hostfile);
- auth_debug_add("Ignored %.200s: bad ownership or modes",
- user_hostfile);
- } else {
- temporarily_use_uid(pw);
- load_hostkeys(hostkeys, host, user_hostfile, 0);
- restore_uid();
- }
- free(user_hostfile);
- }
- host_status = check_key_in_hostkeys(hostkeys, key, &found);
- if (host_status == HOST_REVOKED)
- error("WARNING: revoked key for %s attempted authentication",
- host);
- else if (host_status == HOST_OK)
- debug_f("key for %s found at %s:%ld",
- found->host, found->file, found->line);
- else
- debug_f("key for host %s not found", host);
-
- free_hostkeys(hostkeys);
-
- return host_status;
- }
-
- struct passwd *
- getpwnamallow(struct ssh *ssh, const char *user)
- {
- #ifdef HAVE_LOGIN_CAP
- extern login_cap_t *lc;
- #ifdef BSD_AUTH
- auth_session_t *as;
- #endif
- #endif
- struct passwd *pw;
- struct connection_info *ci;
- u_int i;
-
- ci = get_connection_info(ssh, 1, options.use_dns);
- ci->user = user;
- parse_server_match_config(&options, &includes, ci);
- log_change_level(options.log_level);
- log_verbose_reset();
- for (i = 0; i < options.num_log_verbose; i++)
- log_verbose_add(options.log_verbose[i]);
- process_permitopen(ssh, &options);
-
- #if defined(_AIX) && defined(HAVE_SETAUTHDB)
- aix_setauthdb(user);
- #endif
-
- pw = getpwnam(user);
-
- #if defined(_AIX) && defined(HAVE_SETAUTHDB)
- aix_restoreauthdb();
- #endif
- if (pw == NULL) {
- logit("Invalid user %.100s from %.100s port %d",
- user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
- #ifdef CUSTOM_FAILED_LOGIN
- record_failed_login(ssh, user,
- auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
- #endif
- #ifdef SSH_AUDIT_EVENTS
- audit_event(ssh, SSH_INVALID_USER);
- #endif /* SSH_AUDIT_EVENTS */
- return (NULL);
- }
- if (!allowed_user(ssh, pw))
- return (NULL);
- #ifdef HAVE_LOGIN_CAP
- if ((lc = login_getpwclass(pw)) == NULL) {
- debug("unable to get login class: %s", user);
- return (NULL);
- }
- #ifdef BSD_AUTH
- if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
- auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
- debug("Approval failure for %s", user);
- pw = NULL;
- }
- if (as != NULL)
- auth_close(as);
- #endif
- #endif
- if (pw != NULL)
- return (pwcopy(pw));
- return (NULL);
- }
-
- /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
- int
- auth_key_is_revoked(struct sshkey *key)
- {
- char *fp = NULL;
- int r;
-
- if (options.revoked_keys_file == NULL)
- return 0;
- if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
- SSH_FP_DEFAULT)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- error_fr(r, "fingerprint key");
- goto out;
- }
-
- r = sshkey_check_revoked(key, options.revoked_keys_file);
- switch (r) {
- case 0:
- break; /* not revoked */
- case SSH_ERR_KEY_REVOKED:
- error("Authentication key %s %s revoked by file %s",
- sshkey_type(key), fp, options.revoked_keys_file);
- goto out;
- default:
- error_r(r, "Error checking authentication key %s %s in "
- "revoked keys file %s", sshkey_type(key), fp,
- options.revoked_keys_file);
- goto out;
- }
-
- /* Success */
- r = 0;
-
- out:
- free(fp);
- return r == 0 ? 0 : 1;
- }
-
- void
- auth_debug_add(const char *fmt,...)
- {
- char buf[1024];
- va_list args;
- int r;
-
- va_start(args, fmt);
- vsnprintf(buf, sizeof(buf), fmt, args);
- va_end(args);
- debug3("%s", buf);
- if (auth_debug != NULL)
- if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0)
- fatal_fr(r, "sshbuf_put_cstring");
- }
-
- void
- auth_debug_send(struct ssh *ssh)
- {
- char *msg;
- int r;
-
- if (auth_debug == NULL)
- return;
- while (sshbuf_len(auth_debug) != 0) {
- if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0)
- fatal_fr(r, "sshbuf_get_cstring");
- ssh_packet_send_debug(ssh, "%s", msg);
- free(msg);
- }
- }
-
- void
- auth_debug_reset(void)
- {
- if (auth_debug != NULL)
- sshbuf_reset(auth_debug);
- else if ((auth_debug = sshbuf_new()) == NULL)
- fatal_f("sshbuf_new failed");
- }
-
- struct passwd *
- fakepw(void)
- {
- static int done = 0;
- static struct passwd fake;
- const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ"
- "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */
- char *cp;
-
- if (done)
- return (&fake);
-
- memset(&fake, 0, sizeof(fake));
- fake.pw_name = "NOUSER";
- fake.pw_passwd = xstrdup("$2a$10$"
- "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
- for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++)
- *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)];
- #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
- fake.pw_gecos = "NOUSER";
- #endif
- fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
- fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
- #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
- fake.pw_class = "";
- #endif
- fake.pw_dir = "/nonexist";
- fake.pw_shell = "/nonexist";
- done = 1;
-
- return (&fake);
- }
-
- /*
- * Returns the remote DNS hostname as a string. The returned string must not
- * be freed. NB. this will usually trigger a DNS query the first time it is
- * called.
- * This function does additional checks on the hostname to mitigate some
- * attacks on based on conflation of hostnames and IP addresses.
- */
-
- static char *
- remote_hostname(struct ssh *ssh)
- {
- struct sockaddr_storage from;
- socklen_t fromlen;
- struct addrinfo hints, *ai, *aitop;
- char name[NI_MAXHOST], ntop2[NI_MAXHOST];
- const char *ntop = ssh_remote_ipaddr(ssh);
-
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(ssh_packet_get_connection_in(ssh),
- (struct sockaddr *)&from, &fromlen) == -1) {
- debug("getpeername failed: %.100s", strerror(errno));
- return xstrdup(ntop);
- }
-
- ipv64_normalise_mapped(&from, &fromlen);
- if (from.ss_family == AF_INET6)
- fromlen = sizeof(struct sockaddr_in6);
-
- debug3("Trying to reverse map address %.100s.", ntop);
- /* Map the IP address to a host name. */
- if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
- NULL, 0, NI_NAMEREQD) != 0) {
- /* Host name not found. Use ip address. */
- return xstrdup(ntop);
- }
-
- /*
- * if reverse lookup result looks like a numeric hostname,
- * someone is trying to trick us by PTR record like following:
- * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
- */
- memset(&hints, 0, sizeof(hints));
- hints.ai_socktype = SOCK_DGRAM; /*dummy*/
- hints.ai_flags = AI_NUMERICHOST;
- if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
- logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
- name, ntop);
- freeaddrinfo(ai);
- return xstrdup(ntop);
- }
-
- /* Names are stored in lowercase. */
- lowercase(name);
-
- /*
- * Map it back to an IP address and check that the given
- * address actually is an address of this host. This is
- * necessary because anyone with access to a name server can
- * define arbitrary names for an IP address. Mapping from
- * name to IP address can be trusted better (but can still be
- * fooled if the intruder has access to the name server of
- * the domain).
- */
- memset(&hints, 0, sizeof(hints));
- hints.ai_family = from.ss_family;
- hints.ai_socktype = SOCK_STREAM;
- if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
- logit("reverse mapping checking getaddrinfo for %.700s "
- "[%s] failed.", name, ntop);
- return xstrdup(ntop);
- }
- /* Look for the address from the list of addresses. */
- for (ai = aitop; ai; ai = ai->ai_next) {
- if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
- sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
- (strcmp(ntop, ntop2) == 0))
- break;
- }
- freeaddrinfo(aitop);
- /* If we reached the end of the list, the address was not there. */
- if (ai == NULL) {
- /* Address not found for the host name. */
- logit("Address %.100s maps to %.600s, but this does not "
- "map back to the address.", ntop, name);
- return xstrdup(ntop);
- }
- return xstrdup(name);
- }
-
- /*
- * Return the canonical name of the host in the other side of the current
- * connection. The host name is cached, so it is efficient to call this
- * several times.
- */
-
- const char *
- auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
- {
- static char *dnsname;
-
- if (!use_dns)
- return ssh_remote_ipaddr(ssh);
- else if (dnsname != NULL)
- return dnsname;
- else {
- dnsname = remote_hostname(ssh);
- return dnsname;
- }
- }
-
- /* These functions link key/cert options to the auth framework */
-
- /* Log sshauthopt options locally and (optionally) for remote transmission */
- void
- auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote)
- {
- int do_env = options.permit_user_env && opts->nenv > 0;
- int do_permitopen = opts->npermitopen > 0 &&
- (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0;
- int do_permitlisten = opts->npermitlisten > 0 &&
- (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0;
- size_t i;
- char msg[1024], buf[64];
-
- snprintf(buf, sizeof(buf), "%d", opts->force_tun_device);
- /* Try to keep this alphabetically sorted */
- snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
- opts->permit_agent_forwarding_flag ? " agent-forwarding" : "",
- opts->force_command == NULL ? "" : " command",
- do_env ? " environment" : "",
- opts->valid_before == 0 ? "" : "expires",
- opts->no_require_user_presence ? " no-touch-required" : "",
- do_permitopen ? " permitopen" : "",
- do_permitlisten ? " permitlisten" : "",
- opts->permit_port_forwarding_flag ? " port-forwarding" : "",
- opts->cert_principals == NULL ? "" : " principals",
- opts->permit_pty_flag ? " pty" : "",
- opts->require_verify ? " uv" : "",
- opts->force_tun_device == -1 ? "" : " tun=",
- opts->force_tun_device == -1 ? "" : buf,
- opts->permit_user_rc ? " user-rc" : "",
- opts->permit_x11_forwarding_flag ? " x11-forwarding" : "");
-
- debug("%s: %s", loc, msg);
- if (do_remote)
- auth_debug_add("%s: %s", loc, msg);
-
- if (options.permit_user_env) {
- for (i = 0; i < opts->nenv; i++) {
- debug("%s: environment: %s", loc, opts->env[i]);
- if (do_remote) {
- auth_debug_add("%s: environment: %s",
- loc, opts->env[i]);
- }
- }
- }
-
- /* Go into a little more details for the local logs. */
- if (opts->valid_before != 0) {
- format_absolute_time(opts->valid_before, buf, sizeof(buf));
- debug("%s: expires at %s", loc, buf);
- }
- if (opts->cert_principals != NULL) {
- debug("%s: authorized principals: \"%s\"",
- loc, opts->cert_principals);
- }
- if (opts->force_command != NULL)
- debug("%s: forced command: \"%s\"", loc, opts->force_command);
- if (do_permitopen) {
- for (i = 0; i < opts->npermitopen; i++) {
- debug("%s: permitted open: %s",
- loc, opts->permitopen[i]);
- }
- }
- if (do_permitlisten) {
- for (i = 0; i < opts->npermitlisten; i++) {
- debug("%s: permitted listen: %s",
- loc, opts->permitlisten[i]);
- }
- }
- }
-
- /* Activate a new set of key/cert options; merging with what is there. */
- int
- auth_activate_options(struct ssh *ssh, struct sshauthopt *opts)
- {
- struct sshauthopt *old = auth_opts;
- const char *emsg = NULL;
-
- debug_f("setting new authentication options");
- if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) {
- error("Inconsistent authentication options: %s", emsg);
- return -1;
- }
- return 0;
- }
-
- /* Disable forwarding, etc for the session */
- void
- auth_restrict_session(struct ssh *ssh)
- {
- struct sshauthopt *restricted;
-
- debug_f("restricting session");
-
- /* A blank sshauthopt defaults to permitting nothing */
- if ((restricted = sshauthopt_new()) == NULL)
- fatal_f("sshauthopt_new failed");
- restricted->permit_pty_flag = 1;
- restricted->restricted = 1;
-
- if (auth_activate_options(ssh, restricted) != 0)
- fatal_f("failed to restrict session");
- sshauthopt_free(restricted);
- }
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