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servconf.c
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servconf.c
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/* $OpenBSD: servconf.c,v 1.306 2017/03/14 07:19:07 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 <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#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
#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "log.h"
#include "buffer.h"
#include "misc.h"
#include "servconf.h"
#include "compat.h"
#include "pathnames.h"
#include "cipher.h"
#include "key.h"
#include "kex.h"
#include "mac.h"
#include "match.h"
#include "channels.h"
#include "groupaccess.h"
#include "canohost.h"
#include "packet.h"
#include "hostfile.h"
#include "auth.h"
#include "myproposal.h"
#include "digest.h"
static void add_listen_addr(ServerOptions *, char *, int);
static void add_one_listen_addr(ServerOptions *, char *, int);
/* Use of privilege separation or not */
extern int use_privsep;
extern Buffer 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->address_family = -1;
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->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_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->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->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->permit_tun = -1;
options->num_permitted_opens = -1;
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->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;
}
/* 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)
{
if (kex_assemble_names(KEX_SERVER_ENCRYPT, &o->ciphers) != 0 ||
kex_assemble_names(KEX_SERVER_MAC, &o->macs) != 0 ||
kex_assemble_names(KEX_SERVER_KEX, &o->kex_algorithms) != 0 ||
kex_assemble_names(KEX_DEFAULT_PK_ALG,
&o->hostkeyalgorithms) != 0 ||
kex_assemble_names(KEX_DEFAULT_PK_ALG,
&o->hostbased_key_types) != 0 ||
kex_assemble_names(KEX_DEFAULT_PK_ALG, &o->pubkey_key_types) != 0)
fatal("kex_assemble_names failed");
}
void
fill_default_server_options(ServerOptions *options)
{
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 */
options->host_key_files[options->num_host_key_files++] =
_PATH_HOST_RSA_KEY_FILE;
options->host_key_files[options->num_host_key_files++] =
_PATH_HOST_DSA_KEY_FILE;
#ifdef OPENSSL_HAS_ECC
options->host_key_files[options->num_host_key_files++] =
_PATH_HOST_ECDSA_KEY_FILE;
#endif
options->host_key_files[options->num_host_key_files++] =
_PATH_HOST_ED25519_KEY_FILE;
}
/* 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, 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->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;
if (options->compression == -1)
options->compression = COMP_DELAYED;
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) {
options->authorized_keys_files[options->num_authkeys_files++] =
xstrdup(_PATH_SSH_USER_PERMITTED_KEYS);
options->authorized_keys_files[options->num_authkeys_files++] =
xstrdup(_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_LOWDELAY;
if (options->ip_qos_bulk == -1)
options->ip_qos_bulk = IPTOS_THROUGHPUT;
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;
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->authorized_principals_file);
CLEAR_ON_NONE(options->adm_forced_command);
CLEAR_ON_NONE(options->chroot_directory);
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;
}
#ifndef HAVE_MMAP
if (use_privsep && options->compression == 1) {
error("This platform does not support both privilege "
"separation and compression");
error("Compression disabled");
options->compression = 0;
}
#endif
}
/* Keyword tokens. */
typedef enum {
sBadOption, /* == unknown option */
/* Portable-specific options */
sUsePAM,
/* Standard Options */
sPort, sHostKeyFile, sLoginGraceTime,
sPermitRootLogin, sLogFacility, sLogLevel,
sRhostsRSAAuthentication, sRSAAuthentication,
sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
sKerberosGetAFSToken,
sKerberosTgtPassing, 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, sPermitTunnel,
sMatch, sPermitOpen, sForceCommand, sChrootDirectory,
sUsePrivilegeSeparation, sAllowAgentForwarding,
sHostCertificate,
sRevokedKeys, sTrustedUserCAKeys, sAuthorizedPrincipalsFile,
sAuthorizedPrincipalsCommand, sAuthorizedPrincipalsCommandUser,
sKexAlgorithms, sIPQoS, sVersionAddendum,
sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,
sAuthenticationMethods, sHostKeyAgent, sPermitUserRC,
sStreamLocalBindMask, sStreamLocalBindUnlink,
sAllowStreamLocalForwarding, sFingerprintHash, sDisableForwarding,
sDeprecated, sIgnore, sUnsupported
} ServerOpCodes;
#define SSHCFG_GLOBAL 0x01 /* allowed in main section of sshd_config */
#define SSHCFG_MATCH 0x02 /* allowed inside a Match section */
#define SSHCFG_ALL (SSHCFG_GLOBAL|SSHCFG_MATCH)
/* 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_GLOBAL },
{ "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 },
{ "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", sChallengeResponseAuthentication, SSHCFG_GLOBAL }, /* alias */
{ "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_GLOBAL },
{ "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 },
{ "permittunnel", sPermitTunnel, SSHCFG_ALL },
{ "permittty", sPermitTTY, SSHCFG_ALL },
{ "permituserrc", sPermitUserRC, SSHCFG_ALL },
{ "match", sMatch, SSHCFG_ALL },
{ "permitopen", sPermitOpen, 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 },
{ "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 },
{ 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 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 (*expanded == '/')
return expanded;
if (getcwd(cwd, sizeof(cwd)) == NULL)
fatal("%s: getcwd: %s", __func__, strerror(errno));
xasprintf(&ret, "%s/%s", cwd, expanded);
free(expanded);
return ret;
}
static void
add_listen_addr(ServerOptions *options, char *addr, int port)
{
u_int i;
if (port == 0)
for (i = 0; i < options->num_ports; i++)
add_one_listen_addr(options, addr, options->ports[i]);
else
add_one_listen_addr(options, addr, port);
}
static void
add_one_listen_addr(ServerOptions *options, char *addr, int port)
{
struct addrinfo hints, *ai, *aitop;
char strport[NI_MAXSERV];
int gaierr;
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;
options->listen_addrs = aitop;
}
/*
* Queue a ListenAddress to be processed once we have all of the Ports
* and AddressFamily options.
*/
static void
queue_listen_addr(ServerOptions *options, char *addr, int port)
{
options->queued_listen_addrs = xreallocarray(
options->queued_listen_addrs, options->num_queued_listens + 1,
sizeof(addr));
options->queued_listen_ports = xreallocarray(
options->queued_listen_ports, options->num_queued_listens + 1,
sizeof(port));
options->queued_listen_addrs[options->num_queued_listens] =
xstrdup(addr);
options->queued_listen_ports[options->num_queued_listens] = port;
options->num_queued_listens++;
}
/*
* Process queued (text) ListenAddress entries.
*/
static void
process_queued_listen_addrs(ServerOptions *options)
{
u_int i;
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++) {
add_listen_addr(options, options->queued_listen_addrs[i],
options->queued_listen_ports[i]);
free(options->queued_listen_addrs[i]);
options->queued_listen_addrs[i] = NULL;
}
free(options->queued_listen_addrs);
options->queued_listen_addrs = NULL;
free(options->queued_listen_ports);
options->queued_listen_ports = NULL;
options->num_queued_listens = 0;
}
struct connection_info *
get_connection_info(int populate, int use_dns)
{
struct ssh *ssh = active_state; /* XXX */
static struct connection_info ci;
if (!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);
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
* [...]
*
* - Add a PermittedChannelRequests directive
* Match Group shell
* PermittedChannelRequests session,forwarded-tcpip
*/
static int
match_cfg_line_group(const char *grps, int line, const char *user)
{
int result = 0;
struct passwd *pw;
if (user == NULL)
goto out;
if ((pw = getpwnam(user)) == NULL) {
debug("Can't match group at line %d because user %.100s does "
"not exist", line, user);
} else if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
debug("Can't Match group because user %.100s not in any group "
"at line %d", user, line);
} else if (ga_match_pattern_list(grps) != 1) {
debug("user %.100s does not match group list %.100s at line %d",
user, grps, line);
} else {
debug("user %.100s matched group list %.100s at line %d", user,
grps, line);
result = 1;
}
out:
ga_free();
return result;
}
/*
* All of the attributes on a single Match line are ANDed together, so we need
* to check every attribute and set the result to zero if any attribute does
* not match.
*/
static int
match_cfg_line(char **condition, int line, struct connection_info *ci)
{
int result = 1, attributes = 0, port;
char *arg, *attrib, *cp = *condition;
if (ci == NULL)
debug3("checking syntax for 'Match %s'", cp);
else
debug3("checking match for '%s' user %s host %s addr %s "
"laddr %s lport %d", cp, ci->user ? ci->user : "(null)",
ci->host ? ci->host : "(null)",
ci->address ? ci->address : "(null)",
ci->laddress ? ci->laddress : "(null)", ci->lport);
while ((attrib = strdelim(&cp)) && *attrib != '\0') {
attributes++;
if (strcasecmp(attrib, "all") == 0) {
if (attributes != 1 ||
((arg = strdelim(&cp)) != NULL && *arg != '\0')) {
error("'all' cannot be combined with other "
"Match attributes");
return -1;
}
*condition = cp;
return 1;
}
if ((arg = strdelim(&cp)) == NULL || *arg == '\0') {
error("Missing Match criteria for %s", attrib);
return -1;
}
if (strcasecmp(attrib, "user") == 0) {
if (ci == NULL || ci->user == NULL) {
result = 0;
continue;
}
if (match_pattern_list(ci->user, arg, 0) != 1)
result = 0;
else
debug("user %.100s matched 'User %.100s' at "
"line %d", ci->user, arg, line);
} else if (strcasecmp(attrib, "group") == 0) {
if (ci == NULL || ci->user == NULL) {
result = 0;
continue;
}
switch (match_cfg_line_group(arg, line, ci->user)) {
case -1:
return -1;
case 0:
result = 0;
}
} else if (strcasecmp(attrib, "host") == 0) {
if (ci == NULL || ci->host == NULL) {
result = 0;
continue;
}
if (match_hostname(ci->host, arg) != 1)
result = 0;
else
debug("connection from %.100s matched 'Host "
"%.100s' at line %d", ci->host, arg, line);
} else if (strcasecmp(attrib, "address") == 0) {
if (ci == NULL || ci->address == NULL) {
result = 0;
continue;
}
switch (addr_match_list(ci->address, arg)) {
case 1:
debug("connection from %.100s matched 'Address "
"%.100s' at line %d", ci->address, arg, line);
break;
case 0:
case -1:
result = 0;
break;
case -2:
return -1;
}
} else if (strcasecmp(attrib, "localaddress") == 0){
if (ci == NULL || ci->laddress == NULL) {
result = 0;
continue;
}
switch (addr_match_list(ci->laddress, arg)) {
case 1:
debug("connection from %.100s matched "
"'LocalAddress %.100s' at line %d",
ci->laddress, arg, line);
break;
case 0:
case -1:
result = 0;
break;
case -2:
return -1;
}
} else if (strcasecmp(attrib, "localport") == 0) {
if ((port = a2port(arg)) == -1) {
error("Invalid LocalPort '%s' on Match line",
arg);
return -1;
}
if (ci == NULL || ci->lport == 0) {
result = 0;
continue;
}
/* TODO support port lists */
if (port == ci->lport)
debug("connection from %.100s matched "
"'LocalPort %d' at line %d",
ci->laddress, port, line);
else
result = 0;
} else {
error("Unsupported Match attribute %s", attrib);
return -1;
}
}
if (attributes == 0) {
error("One or more attributes required for Match");
return -1;
}
if (ci != NULL)
debug3("match %sfound", result ? "" : "not ");
*condition = cp;
return result;
}
#define WHITESPACE " \t\r\n"
/* Multistate option parsing */
struct multistate {
char *key;
int value;
};
static const struct multistate multistate_addressfamily[] = {
{ "inet", AF_INET },
{ "inet6", AF_INET6 },
{ "any", AF_UNSPEC },
{ NULL, -1 }
};
static const struct multistate multistate_permitrootlogin[] = {
{ "without-password", PERMIT_NO_PASSWD },
{ "prohibit-password", PERMIT_NO_PASSWD },
{ "forced-commands-only", PERMIT_FORCED_ONLY },
{ "yes", PERMIT_YES },
{ "no", PERMIT_NO },
{ NULL, -1 }
};
static const struct multistate multistate_compression[] = {
{ "yes", COMP_DELAYED },
{ "delayed", COMP_DELAYED },
{ "no", COMP_NONE },
{ NULL, -1 }
};
static const struct multistate multistate_gatewayports[] = {
{ "clientspecified", 2 },
{ "yes", 1 },
{ "no", 0 },
{ NULL, -1 }
};
static const struct multistate multistate_privsep[] = {
{ "yes", PRIVSEP_NOSANDBOX },
{ "sandbox", PRIVSEP_ON },
{ "nosandbox", PRIVSEP_NOSANDBOX },
{ "no", PRIVSEP_OFF },
{ NULL, -1 }
};
static const struct multistate multistate_tcpfwd[] = {
{ "yes", FORWARD_ALLOW },
{ "all", FORWARD_ALLOW },
{ "no", FORWARD_DENY },
{ "remote", FORWARD_REMOTE },
{ "local", FORWARD_LOCAL },
{ NULL, -1 }
};
int
process_server_config_line(ServerOptions *options, char *line,
const char *filename, int linenum, int *activep,
struct connection_info *connectinfo)
{
char *cp, **charptr, *arg, *p;
int cmdline = 0, *intptr, value, value2, n, port;
SyslogFacility *log_facility_ptr;
LogLevel *log_level_ptr;
ServerOpCodes opcode;
u_int i, flags = 0;
size_t len;
long long val64;
const struct multistate *multistate_ptr;
/* Strip trailing whitespace. Allow \f (form feed) at EOL only */
if ((len = strlen(line)) == 0)
return 0;
for (len--; len > 0; len--) {
if (strchr(WHITESPACE "\f", line[len]) == NULL)
break;
line[len] = '\0';
}
cp = line;
if ((arg = strdelim(&cp)) == NULL)
return 0;
/* Ignore leading whitespace */
if (*arg == '\0')
arg = strdelim(&cp);
if (!arg || !*arg || *arg == '#')
return 0;
intptr = NULL;
charptr = NULL;
opcode = parse_token(arg, filename, linenum, &flags);
if (activep == NULL) { /* We are processing a command line directive */
cmdline = 1;
activep = &cmdline;
}
if (*activep && opcode != sMatch)
debug3("%s:%d setting %s %s", filename, linenum, arg, cp);
if (*activep == 0 && !(flags & SSHCFG_MATCH)) {
if (connectinfo == NULL) {
fatal("%s line %d: Directive '%s' is not allowed "
"within a Match block", filename, linenum, arg);
} else { /* this is a directive we have already processed */