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servconf.c
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servconf.c
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/* $OpenBSD: servconf.c,v 1.371 2020/10/18 11:32:02 djm Exp $ */
/*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#ifdef __OpenBSD__
#include <sys/sysctl.h>
#endif
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef HAVE_NET_ROUTE_H
#include <net/route.h>
#endif
#include <ctype.h>
#include <netdb.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <limits.h>
#include <stdarg.h>
#include <errno.h>
#ifdef HAVE_UTIL_H
#include <util.h>
#endif
#ifdef USE_SYSTEM_GLOB
# include <glob.h>
#else
# include "openbsd-compat/glob.h"
#endif
#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "log.h"
#include "sshbuf.h"
#include "misc.h"
#include "servconf.h"
#include "compat.h"
#include "pathnames.h"
#include "cipher.h"
#include "sshkey.h"
#include "kex.h"
#include "mac.h"
#include "match.h"
#include "channels.h"
#include "groupaccess.h"
#include "canohost.h"
#include "packet.h"
#include "ssherr.h"
#include "hostfile.h"
#include "auth.h"
#include "myproposal.h"
#include "digest.h"
static void add_listen_addr(ServerOptions *, const char *,
const char *, int);
static void add_one_listen_addr(ServerOptions *, const char *,
const char *, int);
static void parse_server_config_depth(ServerOptions *options,
const char *filename, struct sshbuf *conf, struct include_list *includes,
struct connection_info *connectinfo, int flags, int *activep, int depth);
/* Use of privilege separation or not */
extern int use_privsep;
extern struct sshbuf *cfg;
/* Initializes the server options to their default values. */
void
initialize_server_options(ServerOptions *options)
{
memset(options, 0, sizeof(*options));
/* Portable-specific options */
options->use_pam = -1;
/* Standard Options */
options->num_ports = 0;
options->ports_from_cmdline = 0;
options->queued_listen_addrs = NULL;
options->num_queued_listens = 0;
options->listen_addrs = NULL;
options->num_listen_addrs = 0;
options->address_family = -1;
options->routing_domain = NULL;
options->num_host_key_files = 0;
options->num_host_cert_files = 0;
options->host_key_agent = NULL;
options->pid_file = NULL;
options->login_grace_time = -1;
options->permit_root_login = PERMIT_NOT_SET;
options->ignore_rhosts = -1;
options->ignore_user_known_hosts = -1;
options->print_motd = -1;
options->print_lastlog = -1;
options->x11_forwarding = -1;
options->x11_display_offset = -1;
options->x11_use_localhost = -1;
options->permit_tty = -1;
options->permit_user_rc = -1;
options->xauth_location = NULL;
options->strict_modes = -1;
options->tcp_keep_alive = -1;
options->log_facility = SYSLOG_FACILITY_NOT_SET;
options->log_level = SYSLOG_LEVEL_NOT_SET;
options->num_log_verbose = 0;
options->log_verbose = NULL;
options->hostbased_authentication = -1;
options->hostbased_uses_name_from_packet_only = -1;
options->hostbased_key_types = NULL;
options->hostkeyalgorithms = NULL;
options->pubkey_authentication = -1;
options->pubkey_auth_options = -1;
options->pubkey_key_types = NULL;
options->kerberos_authentication = -1;
options->kerberos_or_local_passwd = -1;
options->kerberos_ticket_cleanup = -1;
options->kerberos_get_afs_token = -1;
options->gss_authentication=-1;
options->gss_cleanup_creds = -1;
options->gss_strict_acceptor = -1;
options->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->challenge_response_authentication = -1;
options->permit_empty_passwd = -1;
options->permit_user_env = -1;
options->permit_user_env_allowlist = NULL;
options->compression = -1;
options->rekey_limit = -1;
options->rekey_interval = -1;
options->allow_tcp_forwarding = -1;
options->allow_streamlocal_forwarding = -1;
options->allow_agent_forwarding = -1;
options->num_allow_users = 0;
options->num_deny_users = 0;
options->num_allow_groups = 0;
options->num_deny_groups = 0;
options->ciphers = NULL;
options->macs = NULL;
options->kex_algorithms = NULL;
options->ca_sign_algorithms = NULL;
options->fwd_opts.gateway_ports = -1;
options->fwd_opts.streamlocal_bind_mask = (mode_t)-1;
options->fwd_opts.streamlocal_bind_unlink = -1;
options->num_subsystems = 0;
options->max_startups_begin = -1;
options->max_startups_rate = -1;
options->max_startups = -1;
options->max_authtries = -1;
options->max_sessions = -1;
options->banner = NULL;
options->use_dns = -1;
options->client_alive_interval = -1;
options->client_alive_count_max = -1;
options->num_authkeys_files = 0;
options->num_accept_env = 0;
options->num_setenv = 0;
options->permit_tun = -1;
options->permitted_opens = NULL;
options->permitted_listens = NULL;
options->adm_forced_command = NULL;
options->chroot_directory = NULL;
options->authorized_keys_command = NULL;
options->authorized_keys_command_user = NULL;
options->revoked_keys_file = NULL;
options->sk_provider = NULL;
options->trusted_user_ca_keys = NULL;
options->authorized_principals_file = NULL;
options->authorized_principals_command = NULL;
options->authorized_principals_command_user = NULL;
options->ip_qos_interactive = -1;
options->ip_qos_bulk = -1;
options->version_addendum = NULL;
options->fingerprint_hash = -1;
options->disable_forwarding = -1;
options->expose_userauth_info = -1;
}
/* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */
static int
option_clear_or_none(const char *o)
{
return o == NULL || strcasecmp(o, "none") == 0;
}
static void
assemble_algorithms(ServerOptions *o)
{
char *all_cipher, *all_mac, *all_kex, *all_key, *all_sig;
char *def_cipher, *def_mac, *def_kex, *def_key, *def_sig;
int r;
all_cipher = cipher_alg_list(',', 0);
all_mac = mac_alg_list(',');
all_kex = kex_alg_list(',');
all_key = sshkey_alg_list(0, 0, 1, ',');
all_sig = sshkey_alg_list(0, 1, 1, ',');
/* remove unsupported algos from default lists */
def_cipher = match_filter_allowlist(KEX_SERVER_ENCRYPT, all_cipher);
def_mac = match_filter_allowlist(KEX_SERVER_MAC, all_mac);
def_kex = match_filter_allowlist(KEX_SERVER_KEX, all_kex);
def_key = match_filter_allowlist(KEX_DEFAULT_PK_ALG, all_key);
def_sig = match_filter_allowlist(SSH_ALLOWED_CA_SIGALGS, all_sig);
#define ASSEMBLE(what, defaults, all) \
do { \
if ((r = kex_assemble_names(&o->what, defaults, all)) != 0) \
fatal_fr(r, "%s", #what); \
} while (0)
ASSEMBLE(ciphers, def_cipher, all_cipher);
ASSEMBLE(macs, def_mac, all_mac);
ASSEMBLE(kex_algorithms, def_kex, all_kex);
ASSEMBLE(hostkeyalgorithms, def_key, all_key);
ASSEMBLE(hostbased_key_types, def_key, all_key);
ASSEMBLE(pubkey_key_types, def_key, all_key);
ASSEMBLE(ca_sign_algorithms, def_sig, all_sig);
#undef ASSEMBLE
free(all_cipher);
free(all_mac);
free(all_kex);
free(all_key);
free(all_sig);
free(def_cipher);
free(def_mac);
free(def_kex);
free(def_key);
free(def_sig);
}
static void
array_append2(const char *file, const int line, const char *directive,
char ***array, int **iarray, u_int *lp, const char *s, int i)
{
if (*lp >= INT_MAX)
fatal("%s line %d: Too many %s entries", file, line, directive);
if (iarray != NULL) {
*iarray = xrecallocarray(*iarray, *lp, *lp + 1,
sizeof(**iarray));
(*iarray)[*lp] = i;
}
*array = xrecallocarray(*array, *lp, *lp + 1, sizeof(**array));
(*array)[*lp] = xstrdup(s);
(*lp)++;
}
static void
array_append(const char *file, const int line, const char *directive,
char ***array, u_int *lp, const char *s)
{
array_append2(file, line, directive, array, NULL, lp, s, 0);
}
void
servconf_add_hostkey(const char *file, const int line,
ServerOptions *options, const char *path, int userprovided)
{
char *apath = derelativise_path(path);
array_append2(file, line, "HostKey",
&options->host_key_files, &options->host_key_file_userprovided,
&options->num_host_key_files, apath, userprovided);
free(apath);
}
void
servconf_add_hostcert(const char *file, const int line,
ServerOptions *options, const char *path)
{
char *apath = derelativise_path(path);
array_append(file, line, "HostCertificate",
&options->host_cert_files, &options->num_host_cert_files, apath);
free(apath);
}
void
fill_default_server_options(ServerOptions *options)
{
u_int i;
/* Portable-specific options */
if (options->use_pam == -1)
options->use_pam = 0;
/* Standard Options */
if (options->num_host_key_files == 0) {
/* fill default hostkeys for protocols */
servconf_add_hostkey("[default]", 0, options,
_PATH_HOST_RSA_KEY_FILE, 0);
#ifdef OPENSSL_HAS_ECC
servconf_add_hostkey("[default]", 0, options,
_PATH_HOST_ECDSA_KEY_FILE, 0);
#endif
servconf_add_hostkey("[default]", 0, options,
_PATH_HOST_ED25519_KEY_FILE, 0);
#ifdef WITH_XMSS
servconf_add_hostkey("[default]", 0, options,
_PATH_HOST_XMSS_KEY_FILE, 0);
#endif /* WITH_XMSS */
}
/* No certificates by default */
if (options->num_ports == 0)
options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
if (options->address_family == -1)
options->address_family = AF_UNSPEC;
if (options->listen_addrs == NULL)
add_listen_addr(options, NULL, NULL, 0);
if (options->pid_file == NULL)
options->pid_file = xstrdup(_PATH_SSH_DAEMON_PID_FILE);
if (options->login_grace_time == -1)
options->login_grace_time = 120;
if (options->permit_root_login == PERMIT_NOT_SET)
options->permit_root_login = PERMIT_NO_PASSWD;
if (options->ignore_rhosts == -1)
options->ignore_rhosts = 1;
if (options->ignore_user_known_hosts == -1)
options->ignore_user_known_hosts = 0;
if (options->print_motd == -1)
options->print_motd = 1;
if (options->print_lastlog == -1)
options->print_lastlog = 1;
if (options->x11_forwarding == -1)
options->x11_forwarding = 0;
if (options->x11_display_offset == -1)
options->x11_display_offset = 10;
if (options->x11_use_localhost == -1)
options->x11_use_localhost = 1;
if (options->xauth_location == NULL)
options->xauth_location = xstrdup(_PATH_XAUTH);
if (options->permit_tty == -1)
options->permit_tty = 1;
if (options->permit_user_rc == -1)
options->permit_user_rc = 1;
if (options->strict_modes == -1)
options->strict_modes = 1;
if (options->tcp_keep_alive == -1)
options->tcp_keep_alive = 1;
if (options->log_facility == SYSLOG_FACILITY_NOT_SET)
options->log_facility = SYSLOG_FACILITY_AUTH;
if (options->log_level == SYSLOG_LEVEL_NOT_SET)
options->log_level = SYSLOG_LEVEL_INFO;
if (options->hostbased_authentication == -1)
options->hostbased_authentication = 0;
if (options->hostbased_uses_name_from_packet_only == -1)
options->hostbased_uses_name_from_packet_only = 0;
if (options->pubkey_authentication == -1)
options->pubkey_authentication = 1;
if (options->pubkey_auth_options == -1)
options->pubkey_auth_options = 0;
if (options->kerberos_authentication == -1)
options->kerberos_authentication = 0;
if (options->kerberos_or_local_passwd == -1)
options->kerberos_or_local_passwd = 1;
if (options->kerberos_ticket_cleanup == -1)
options->kerberos_ticket_cleanup = 1;
if (options->kerberos_get_afs_token == -1)
options->kerberos_get_afs_token = 0;
if (options->gss_authentication == -1)
options->gss_authentication = 0;
if (options->gss_cleanup_creds == -1)
options->gss_cleanup_creds = 1;
if (options->gss_strict_acceptor == -1)
options->gss_strict_acceptor = 1;
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
options->kbd_interactive_authentication = 0;
if (options->challenge_response_authentication == -1)
options->challenge_response_authentication = 1;
if (options->permit_empty_passwd == -1)
options->permit_empty_passwd = 0;
if (options->permit_user_env == -1) {
options->permit_user_env = 0;
options->permit_user_env_allowlist = NULL;
}
if (options->compression == -1)
#ifdef WITH_ZLIB
options->compression = COMP_DELAYED;
#else
options->compression = COMP_NONE;
#endif
if (options->rekey_limit == -1)
options->rekey_limit = 0;
if (options->rekey_interval == -1)
options->rekey_interval = 0;
if (options->allow_tcp_forwarding == -1)
options->allow_tcp_forwarding = FORWARD_ALLOW;
if (options->allow_streamlocal_forwarding == -1)
options->allow_streamlocal_forwarding = FORWARD_ALLOW;
if (options->allow_agent_forwarding == -1)
options->allow_agent_forwarding = 1;
if (options->fwd_opts.gateway_ports == -1)
options->fwd_opts.gateway_ports = 0;
if (options->max_startups == -1)
options->max_startups = 100;
if (options->max_startups_rate == -1)
options->max_startups_rate = 30; /* 30% */
if (options->max_startups_begin == -1)
options->max_startups_begin = 10;
if (options->max_authtries == -1)
options->max_authtries = DEFAULT_AUTH_FAIL_MAX;
if (options->max_sessions == -1)
options->max_sessions = DEFAULT_SESSIONS_MAX;
if (options->use_dns == -1)
options->use_dns = 0;
if (options->client_alive_interval == -1)
options->client_alive_interval = 0;
if (options->client_alive_count_max == -1)
options->client_alive_count_max = 3;
if (options->num_authkeys_files == 0) {
array_append("[default]", 0, "AuthorizedKeysFiles",
&options->authorized_keys_files,
&options->num_authkeys_files,
_PATH_SSH_USER_PERMITTED_KEYS);
array_append("[default]", 0, "AuthorizedKeysFiles",
&options->authorized_keys_files,
&options->num_authkeys_files,
_PATH_SSH_USER_PERMITTED_KEYS2);
}
if (options->permit_tun == -1)
options->permit_tun = SSH_TUNMODE_NO;
if (options->ip_qos_interactive == -1)
options->ip_qos_interactive = IPTOS_DSCP_AF21;
if (options->ip_qos_bulk == -1)
options->ip_qos_bulk = IPTOS_DSCP_CS1;
if (options->version_addendum == NULL)
options->version_addendum = xstrdup("");
if (options->fwd_opts.streamlocal_bind_mask == (mode_t)-1)
options->fwd_opts.streamlocal_bind_mask = 0177;
if (options->fwd_opts.streamlocal_bind_unlink == -1)
options->fwd_opts.streamlocal_bind_unlink = 0;
if (options->fingerprint_hash == -1)
options->fingerprint_hash = SSH_FP_HASH_DEFAULT;
if (options->disable_forwarding == -1)
options->disable_forwarding = 0;
if (options->expose_userauth_info == -1)
options->expose_userauth_info = 0;
if (options->sk_provider == NULL)
options->sk_provider = xstrdup("internal");
assemble_algorithms(options);
/* Turn privilege separation and sandboxing on by default */
if (use_privsep == -1)
use_privsep = PRIVSEP_ON;
#define CLEAR_ON_NONE(v) \
do { \
if (option_clear_or_none(v)) { \
free(v); \
v = NULL; \
} \
} while(0)
CLEAR_ON_NONE(options->pid_file);
CLEAR_ON_NONE(options->xauth_location);
CLEAR_ON_NONE(options->banner);
CLEAR_ON_NONE(options->trusted_user_ca_keys);
CLEAR_ON_NONE(options->revoked_keys_file);
CLEAR_ON_NONE(options->sk_provider);
CLEAR_ON_NONE(options->authorized_principals_file);
CLEAR_ON_NONE(options->adm_forced_command);
CLEAR_ON_NONE(options->chroot_directory);
CLEAR_ON_NONE(options->routing_domain);
CLEAR_ON_NONE(options->host_key_agent);
for (i = 0; i < options->num_host_key_files; i++)
CLEAR_ON_NONE(options->host_key_files[i]);
for (i = 0; i < options->num_host_cert_files; i++)
CLEAR_ON_NONE(options->host_cert_files[i]);
#undef CLEAR_ON_NONE
/* Similar handling for AuthenticationMethods=any */
if (options->num_auth_methods == 1 &&
strcmp(options->auth_methods[0], "any") == 0) {
free(options->auth_methods[0]);
options->auth_methods[0] = NULL;
options->num_auth_methods = 0;
}
}
/* Keyword tokens. */
typedef enum {
sBadOption, /* == unknown option */
/* Portable-specific options */
sUsePAM,
/* Standard Options */
sPort, sHostKeyFile, sLoginGraceTime,
sPermitRootLogin, sLogFacility, sLogLevel, sLogVerbose,
sRhostsRSAAuthentication, sRSAAuthentication,
sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
sKerberosGetAFSToken, sChallengeResponseAuthentication,
sPasswordAuthentication, sKbdInteractiveAuthentication,
sListenAddress, sAddressFamily,
sPrintMotd, sPrintLastLog, sIgnoreRhosts,
sX11Forwarding, sX11DisplayOffset, sX11UseLocalhost,
sPermitTTY, sStrictModes, sEmptyPasswd, sTCPKeepAlive,
sPermitUserEnvironment, sAllowTcpForwarding, sCompression,
sRekeyLimit, sAllowUsers, sDenyUsers, sAllowGroups, sDenyGroups,
sIgnoreUserKnownHosts, sCiphers, sMacs, sPidFile,
sGatewayPorts, sPubkeyAuthentication, sPubkeyAcceptedKeyTypes,
sXAuthLocation, sSubsystem, sMaxStartups, sMaxAuthTries, sMaxSessions,
sBanner, sUseDNS, sHostbasedAuthentication,
sHostbasedUsesNameFromPacketOnly, sHostbasedAcceptedKeyTypes,
sHostKeyAlgorithms,
sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
sAcceptEnv, sSetEnv, sPermitTunnel,
sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
sUsePrivilegeSeparation, sAllowAgentForwarding,
sHostCertificate, sInclude,
sRevokedKeys, sTrustedUserCAKeys, sAuthorizedPrincipalsFile,
sAuthorizedPrincipalsCommand, sAuthorizedPrincipalsCommandUser,
sKexAlgorithms, sCASignatureAlgorithms, sIPQoS, sVersionAddendum,
sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,
sAuthenticationMethods, sHostKeyAgent, sPermitUserRC,
sStreamLocalBindMask, sStreamLocalBindUnlink,
sAllowStreamLocalForwarding, sFingerprintHash, sDisableForwarding,
sExposeAuthInfo, sRDomain, sPubkeyAuthOptions, sSecurityKeyProvider,
sDeprecated, sIgnore, sUnsupported
} ServerOpCodes;
#define SSHCFG_GLOBAL 0x01 /* allowed in main section of config */
#define SSHCFG_MATCH 0x02 /* allowed inside a Match section */
#define SSHCFG_ALL (SSHCFG_GLOBAL|SSHCFG_MATCH)
#define SSHCFG_NEVERMATCH 0x04 /* Match never matches; internal only */
#define SSHCFG_MATCH_ONLY 0x08 /* Match only in conditional blocks; internal only */
/* Textual representation of the tokens. */
static struct {
const char *name;
ServerOpCodes opcode;
u_int flags;
} keywords[] = {
/* Portable-specific options */
#ifdef USE_PAM
{ "usepam", sUsePAM, SSHCFG_GLOBAL },
#else
{ "usepam", sUnsupported, SSHCFG_GLOBAL },
#endif
{ "pamauthenticationviakbdint", sDeprecated, SSHCFG_GLOBAL },
/* Standard Options */
{ "port", sPort, SSHCFG_GLOBAL },
{ "hostkey", sHostKeyFile, SSHCFG_GLOBAL },
{ "hostdsakey", sHostKeyFile, SSHCFG_GLOBAL }, /* alias */
{ "hostkeyagent", sHostKeyAgent, SSHCFG_GLOBAL },
{ "pidfile", sPidFile, SSHCFG_GLOBAL },
{ "serverkeybits", sDeprecated, SSHCFG_GLOBAL },
{ "logingracetime", sLoginGraceTime, SSHCFG_GLOBAL },
{ "keyregenerationinterval", sDeprecated, SSHCFG_GLOBAL },
{ "permitrootlogin", sPermitRootLogin, SSHCFG_ALL },
{ "syslogfacility", sLogFacility, SSHCFG_GLOBAL },
{ "loglevel", sLogLevel, SSHCFG_ALL },
{ "logverbose", sLogVerbose, SSHCFG_ALL },
{ "rhostsauthentication", sDeprecated, SSHCFG_GLOBAL },
{ "rhostsrsaauthentication", sDeprecated, SSHCFG_ALL },
{ "hostbasedauthentication", sHostbasedAuthentication, SSHCFG_ALL },
{ "hostbasedusesnamefrompacketonly", sHostbasedUsesNameFromPacketOnly, SSHCFG_ALL },
{ "hostbasedacceptedkeytypes", sHostbasedAcceptedKeyTypes, SSHCFG_ALL },
{ "hostkeyalgorithms", sHostKeyAlgorithms, SSHCFG_GLOBAL },
{ "rsaauthentication", sDeprecated, SSHCFG_ALL },
{ "pubkeyauthentication", sPubkeyAuthentication, SSHCFG_ALL },
{ "pubkeyacceptedkeytypes", sPubkeyAcceptedKeyTypes, SSHCFG_ALL },
{ "pubkeyauthoptions", sPubkeyAuthOptions, SSHCFG_ALL },
{ "dsaauthentication", sPubkeyAuthentication, SSHCFG_GLOBAL }, /* alias */
#ifdef KRB5
{ "kerberosauthentication", sKerberosAuthentication, SSHCFG_ALL },
{ "kerberosorlocalpasswd", sKerberosOrLocalPasswd, SSHCFG_GLOBAL },
{ "kerberosticketcleanup", sKerberosTicketCleanup, SSHCFG_GLOBAL },
#ifdef USE_AFS
{ "kerberosgetafstoken", sKerberosGetAFSToken, SSHCFG_GLOBAL },
#else
{ "kerberosgetafstoken", sUnsupported, SSHCFG_GLOBAL },
#endif
#else
{ "kerberosauthentication", sUnsupported, SSHCFG_ALL },
{ "kerberosorlocalpasswd", sUnsupported, SSHCFG_GLOBAL },
{ "kerberosticketcleanup", sUnsupported, SSHCFG_GLOBAL },
{ "kerberosgetafstoken", sUnsupported, SSHCFG_GLOBAL },
#endif
{ "kerberostgtpassing", sUnsupported, SSHCFG_GLOBAL },
{ "afstokenpassing", sUnsupported, SSHCFG_GLOBAL },
#ifdef GSSAPI
{ "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
{ "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
#else
{ "gssapiauthentication", sUnsupported, SSHCFG_ALL },
{ "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
#endif
{ "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
{ "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL },
{ "skeyauthentication", sDeprecated, SSHCFG_GLOBAL },
{ "checkmail", sDeprecated, SSHCFG_GLOBAL },
{ "listenaddress", sListenAddress, SSHCFG_GLOBAL },
{ "addressfamily", sAddressFamily, SSHCFG_GLOBAL },
{ "printmotd", sPrintMotd, SSHCFG_GLOBAL },
#ifdef DISABLE_LASTLOG
{ "printlastlog", sUnsupported, SSHCFG_GLOBAL },
#else
{ "printlastlog", sPrintLastLog, SSHCFG_GLOBAL },
#endif
{ "ignorerhosts", sIgnoreRhosts, SSHCFG_ALL },
{ "ignoreuserknownhosts", sIgnoreUserKnownHosts, SSHCFG_GLOBAL },
{ "x11forwarding", sX11Forwarding, SSHCFG_ALL },
{ "x11displayoffset", sX11DisplayOffset, SSHCFG_ALL },
{ "x11uselocalhost", sX11UseLocalhost, SSHCFG_ALL },
{ "xauthlocation", sXAuthLocation, SSHCFG_GLOBAL },
{ "strictmodes", sStrictModes, SSHCFG_GLOBAL },
{ "permitemptypasswords", sEmptyPasswd, SSHCFG_ALL },
{ "permituserenvironment", sPermitUserEnvironment, SSHCFG_GLOBAL },
{ "uselogin", sDeprecated, SSHCFG_GLOBAL },
{ "compression", sCompression, SSHCFG_GLOBAL },
{ "rekeylimit", sRekeyLimit, SSHCFG_ALL },
{ "tcpkeepalive", sTCPKeepAlive, SSHCFG_GLOBAL },
{ "keepalive", sTCPKeepAlive, SSHCFG_GLOBAL }, /* obsolete alias */
{ "allowtcpforwarding", sAllowTcpForwarding, SSHCFG_ALL },
{ "allowagentforwarding", sAllowAgentForwarding, SSHCFG_ALL },
{ "allowusers", sAllowUsers, SSHCFG_ALL },
{ "denyusers", sDenyUsers, SSHCFG_ALL },
{ "allowgroups", sAllowGroups, SSHCFG_ALL },
{ "denygroups", sDenyGroups, SSHCFG_ALL },
{ "ciphers", sCiphers, SSHCFG_GLOBAL },
{ "macs", sMacs, SSHCFG_GLOBAL },
{ "protocol", sIgnore, SSHCFG_GLOBAL },
{ "gatewayports", sGatewayPorts, SSHCFG_ALL },
{ "subsystem", sSubsystem, SSHCFG_GLOBAL },
{ "maxstartups", sMaxStartups, SSHCFG_GLOBAL },
{ "maxauthtries", sMaxAuthTries, SSHCFG_ALL },
{ "maxsessions", sMaxSessions, SSHCFG_ALL },
{ "banner", sBanner, SSHCFG_ALL },
{ "usedns", sUseDNS, SSHCFG_GLOBAL },
{ "verifyreversemapping", sDeprecated, SSHCFG_GLOBAL },
{ "reversemappingcheck", sDeprecated, SSHCFG_GLOBAL },
{ "clientaliveinterval", sClientAliveInterval, SSHCFG_ALL },
{ "clientalivecountmax", sClientAliveCountMax, SSHCFG_ALL },
{ "authorizedkeysfile", sAuthorizedKeysFile, SSHCFG_ALL },
{ "authorizedkeysfile2", sDeprecated, SSHCFG_ALL },
{ "useprivilegeseparation", sDeprecated, SSHCFG_GLOBAL},
{ "acceptenv", sAcceptEnv, SSHCFG_ALL },
{ "setenv", sSetEnv, SSHCFG_ALL },
{ "permittunnel", sPermitTunnel, SSHCFG_ALL },
{ "permittty", sPermitTTY, SSHCFG_ALL },
{ "permituserrc", sPermitUserRC, SSHCFG_ALL },
{ "match", sMatch, SSHCFG_ALL },
{ "permitopen", sPermitOpen, SSHCFG_ALL },
{ "permitlisten", sPermitListen, SSHCFG_ALL },
{ "forcecommand", sForceCommand, SSHCFG_ALL },
{ "chrootdirectory", sChrootDirectory, SSHCFG_ALL },
{ "hostcertificate", sHostCertificate, SSHCFG_GLOBAL },
{ "revokedkeys", sRevokedKeys, SSHCFG_ALL },
{ "trustedusercakeys", sTrustedUserCAKeys, SSHCFG_ALL },
{ "authorizedprincipalsfile", sAuthorizedPrincipalsFile, SSHCFG_ALL },
{ "kexalgorithms", sKexAlgorithms, SSHCFG_GLOBAL },
{ "include", sInclude, SSHCFG_ALL },
{ "ipqos", sIPQoS, SSHCFG_ALL },
{ "authorizedkeyscommand", sAuthorizedKeysCommand, SSHCFG_ALL },
{ "authorizedkeyscommanduser", sAuthorizedKeysCommandUser, SSHCFG_ALL },
{ "authorizedprincipalscommand", sAuthorizedPrincipalsCommand, SSHCFG_ALL },
{ "authorizedprincipalscommanduser", sAuthorizedPrincipalsCommandUser, SSHCFG_ALL },
{ "versionaddendum", sVersionAddendum, SSHCFG_GLOBAL },
{ "authenticationmethods", sAuthenticationMethods, SSHCFG_ALL },
{ "streamlocalbindmask", sStreamLocalBindMask, SSHCFG_ALL },
{ "streamlocalbindunlink", sStreamLocalBindUnlink, SSHCFG_ALL },
{ "allowstreamlocalforwarding", sAllowStreamLocalForwarding, SSHCFG_ALL },
{ "fingerprinthash", sFingerprintHash, SSHCFG_GLOBAL },
{ "disableforwarding", sDisableForwarding, SSHCFG_ALL },
{ "exposeauthinfo", sExposeAuthInfo, SSHCFG_ALL },
{ "rdomain", sRDomain, SSHCFG_ALL },
{ "casignaturealgorithms", sCASignatureAlgorithms, SSHCFG_ALL },
{ "securitykeyprovider", sSecurityKeyProvider, SSHCFG_GLOBAL },
{ NULL, sBadOption, 0 }
};
static struct {
int val;
char *text;
} tunmode_desc[] = {
{ SSH_TUNMODE_NO, "no" },
{ SSH_TUNMODE_POINTOPOINT, "point-to-point" },
{ SSH_TUNMODE_ETHERNET, "ethernet" },
{ SSH_TUNMODE_YES, "yes" },
{ -1, NULL }
};
/* Returns an opcode name from its number */
static const char *
lookup_opcode_name(ServerOpCodes code)
{
u_int i;
for (i = 0; keywords[i].name != NULL; i++)
if (keywords[i].opcode == code)
return(keywords[i].name);
return "UNKNOWN";
}
/*
* Returns the number of the token pointed to by cp or sBadOption.
*/
static ServerOpCodes
parse_token(const char *cp, const char *filename,
int linenum, u_int *flags)
{
u_int i;
for (i = 0; keywords[i].name; i++)
if (strcasecmp(cp, keywords[i].name) == 0) {
*flags = keywords[i].flags;
return keywords[i].opcode;
}
error("%s: line %d: Bad configuration option: %s",
filename, linenum, cp);
return sBadOption;
}
char *
derelativise_path(const char *path)
{
char *expanded, *ret, cwd[PATH_MAX];
if (strcasecmp(path, "none") == 0)
return xstrdup("none");
expanded = tilde_expand_filename(path, getuid());
if (path_absolute(expanded))
return expanded;
if (getcwd(cwd, sizeof(cwd)) == NULL)
fatal_f("getcwd: %s", strerror(errno));
xasprintf(&ret, "%s/%s", cwd, expanded);
free(expanded);
return ret;
}
static void
add_listen_addr(ServerOptions *options, const char *addr,
const char *rdomain, int port)
{
u_int i;
if (port > 0)
add_one_listen_addr(options, addr, rdomain, port);
else {
for (i = 0; i < options->num_ports; i++) {
add_one_listen_addr(options, addr, rdomain,
options->ports[i]);
}
}
}
static void
add_one_listen_addr(ServerOptions *options, const char *addr,
const char *rdomain, int port)
{
struct addrinfo hints, *ai, *aitop;
char strport[NI_MAXSERV];
int gaierr;
u_int i;
/* Find listen_addrs entry for this rdomain */
for (i = 0; i < options->num_listen_addrs; i++) {
if (rdomain == NULL && options->listen_addrs[i].rdomain == NULL)
break;
if (rdomain == NULL || options->listen_addrs[i].rdomain == NULL)
continue;
if (strcmp(rdomain, options->listen_addrs[i].rdomain) == 0)
break;
}
if (i >= options->num_listen_addrs) {
/* No entry for this rdomain; allocate one */
if (i >= INT_MAX)
fatal_f("too many listen addresses");
options->listen_addrs = xrecallocarray(options->listen_addrs,
options->num_listen_addrs, options->num_listen_addrs + 1,
sizeof(*options->listen_addrs));
i = options->num_listen_addrs++;
if (rdomain != NULL)
options->listen_addrs[i].rdomain = xstrdup(rdomain);
}
/* options->listen_addrs[i] points to the addresses for this rdomain */
memset(&hints, 0, sizeof(hints));
hints.ai_family = options->address_family;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = (addr == NULL) ? AI_PASSIVE : 0;
snprintf(strport, sizeof strport, "%d", port);
if ((gaierr = getaddrinfo(addr, strport, &hints, &aitop)) != 0)
fatal("bad addr or host: %s (%s)",
addr ? addr : "<NULL>",
ssh_gai_strerror(gaierr));
for (ai = aitop; ai->ai_next; ai = ai->ai_next)
;
ai->ai_next = options->listen_addrs[i].addrs;
options->listen_addrs[i].addrs = aitop;
}
/* Returns nonzero if the routing domain name is valid */
static int
valid_rdomain(const char *name)
{
#if defined(HAVE_SYS_VALID_RDOMAIN)
return sys_valid_rdomain(name);
#elif defined(__OpenBSD__)
const char *errstr;
long long num;
struct rt_tableinfo info;
int mib[6];
size_t miblen = sizeof(mib);
if (name == NULL)
return 1;
num = strtonum(name, 0, 255, &errstr);
if (errstr != NULL)
return 0;
/* Check whether the table actually exists */
memset(mib, 0, sizeof(mib));
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[4] = NET_RT_TABLE;
mib[5] = (int)num;
if (sysctl(mib, 6, &info, &miblen, NULL, 0) == -1)
return 0;
return 1;
#else /* defined(__OpenBSD__) */
error("Routing domains are not supported on this platform");
return 0;
#endif
}
/*
* Queue a ListenAddress to be processed once we have all of the Ports
* and AddressFamily options.
*/
static void
queue_listen_addr(ServerOptions *options, const char *addr,
const char *rdomain, int port)
{
struct queued_listenaddr *qla;
options->queued_listen_addrs = xrecallocarray(
options->queued_listen_addrs,
options->num_queued_listens, options->num_queued_listens + 1,
sizeof(*options->queued_listen_addrs));
qla = &options->queued_listen_addrs[options->num_queued_listens++];
qla->addr = xstrdup(addr);
qla->port = port;
qla->rdomain = rdomain == NULL ? NULL : xstrdup(rdomain);
}
/*
* Process queued (text) ListenAddress entries.
*/
static void
process_queued_listen_addrs(ServerOptions *options)
{
u_int i;
struct queued_listenaddr *qla;
if (options->num_ports == 0)
options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
if (options->address_family == -1)
options->address_family = AF_UNSPEC;
for (i = 0; i < options->num_queued_listens; i++) {
qla = &options->queued_listen_addrs[i];
add_listen_addr(options, qla->addr, qla->rdomain, qla->port);
free(qla->addr);
free(qla->rdomain);
}
free(options->queued_listen_addrs);
options->queued_listen_addrs = NULL;
options->num_queued_listens = 0;
}
/*
* Inform channels layer of permitopen options for a single forwarding
* direction (local/remote).
*/
static void
process_permitopen_list(struct ssh *ssh, ServerOpCodes opcode,
char **opens, u_int num_opens)
{
u_int i;
int port;
char *host, *arg, *oarg, ch;
int where = opcode == sPermitOpen ? FORWARD_LOCAL : FORWARD_REMOTE;
const char *what = lookup_opcode_name(opcode);
channel_clear_permission(ssh, FORWARD_ADM, where);
if (num_opens == 0)
return; /* permit any */
/* handle keywords: "any" / "none" */
if (num_opens == 1 && strcmp(opens[0], "any") == 0)
return;
if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
channel_disable_admin(ssh, where);
return;
}
/* Otherwise treat it as a list of permitted host:port */
for (i = 0; i < num_opens; i++) {
oarg = arg = xstrdup(opens[i]);
ch = '\0';
host = hpdelim2(&arg, &ch);
if (host == NULL || ch == '/')
fatal_f("missing host in %s", what);
host = cleanhostname(host);
if (arg == NULL || ((port = permitopen_port(arg)) < 0))
fatal_f("bad port number in %s", what);
/* Send it to channels layer */
channel_add_permission(ssh, FORWARD_ADM,
where, host, port);
free(oarg);
}
}
/*
* Inform channels layer of permitopen options from configuration.
*/
void
process_permitopen(struct ssh *ssh, ServerOptions *options)
{
process_permitopen_list(ssh, sPermitOpen,
options->permitted_opens, options->num_permitted_opens);
process_permitopen_list(ssh, sPermitListen,
options->permitted_listens,
options->num_permitted_listens);
}
struct connection_info *
get_connection_info(struct ssh *ssh, int populate, int use_dns)
{
static struct connection_info ci;
if (ssh == NULL || !populate)
return &ci;
ci.host = auth_get_canonical_hostname(ssh, use_dns);
ci.address = ssh_remote_ipaddr(ssh);
ci.laddress = ssh_local_ipaddr(ssh);
ci.lport = ssh_local_port(ssh);
ci.rdomain = ssh_packet_rdomain_in(ssh);
return &ci;
}
/*
* The strategy for the Match blocks is that the config file is parsed twice.
*
* The first time is at startup. activep is initialized to 1 and the
* directives in the global context are processed and acted on. Hitting a
* Match directive unsets activep and the directives inside the block are
* checked for syntax only.
*
* The second time is after a connection has been established but before
* authentication. activep is initialized to 2 and global config directives
* are ignored since they have already been processed. If the criteria in a
* Match block is met, activep is set and the subsequent directives
* processed and actioned until EOF or another Match block unsets it. Any
* options set are copied into the main server config.
*
* Potential additions/improvements:
* - Add Match support for pre-kex directives, eg. Ciphers.
*
* - Add a Tag directive (idea from David Leonard) ala pf, eg:
* Match Address 192.168.0.*
* Tag trusted
* Match Group wheel
* Tag trusted
* Match Tag trusted
* AllowTcpForwarding yes
* GatewayPorts clientspecified
* [...]
*