openssh/servconf.c

731 lines
21 KiB
C

/*
* 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"
RCSID("$OpenBSD: servconf.c,v 1.63 2001/01/22 23:06:39 markus Exp $");
#ifdef KRB4
#include <krb.h>
#endif
#ifdef AFS
#include <kafs.h>
#endif
#include "ssh.h"
#include "log.h"
#include "servconf.h"
#include "xmalloc.h"
#include "compat.h"
#include "pathnames.h"
#include "tildexpand.h"
#include "misc.h"
#include "cipher.h"
/* add listen address */
void add_listen_addr(ServerOptions *options, char *addr);
/* AF_UNSPEC or AF_INET or AF_INET6 */
extern int IPv4or6;
/* Initializes the server options to their default values. */
void
initialize_server_options(ServerOptions *options)
{
memset(options, 0, sizeof(*options));
options->num_ports = 0;
options->ports_from_cmdline = 0;
options->listen_addrs = NULL;
options->num_host_key_files = 0;
options->pid_file = NULL;
options->server_key_bits = -1;
options->login_grace_time = -1;
options->key_regeneration_time = -1;
options->permit_root_login = -1;
options->ignore_rhosts = -1;
options->ignore_user_known_hosts = -1;
options->print_motd = -1;
options->check_mail = -1;
options->x11_forwarding = -1;
options->x11_display_offset = -1;
options->xauth_location = NULL;
options->strict_modes = -1;
options->keepalives = -1;
options->log_facility = (SyslogFacility) - 1;
options->log_level = (LogLevel) - 1;
options->rhosts_authentication = -1;
options->rhosts_rsa_authentication = -1;
options->rsa_authentication = -1;
options->pubkey_authentication = -1;
#ifdef KRB4
options->kerberos_authentication = -1;
options->kerberos_or_local_passwd = -1;
options->kerberos_ticket_cleanup = -1;
#endif
#ifdef AFS
options->kerberos_tgt_passing = -1;
options->afs_token_passing = -1;
#endif
options->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->challenge_reponse_authentication = -1;
options->permit_empty_passwd = -1;
options->use_login = -1;
options->allow_tcp_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->protocol = SSH_PROTO_UNKNOWN;
options->gateway_ports = -1;
options->num_subsystems = 0;
options->max_startups_begin = -1;
options->max_startups_rate = -1;
options->max_startups = -1;
options->banner = NULL;
}
void
fill_default_server_options(ServerOptions *options)
{
if (options->protocol == SSH_PROTO_UNKNOWN)
options->protocol = SSH_PROTO_1|SSH_PROTO_2;
if (options->num_host_key_files == 0) {
/* fill default hostkeys for protocols */
if (options->protocol & SSH_PROTO_1)
options->host_key_files[options->num_host_key_files++] = _PATH_HOST_KEY_FILE;
if (options->protocol & SSH_PROTO_2)
options->host_key_files[options->num_host_key_files++] = _PATH_HOST_DSA_KEY_FILE;
}
if (options->num_ports == 0)
options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
if (options->listen_addrs == NULL)
add_listen_addr(options, NULL);
if (options->pid_file == NULL)
options->pid_file = _PATH_SSH_DAEMON_PID_FILE;
if (options->server_key_bits == -1)
options->server_key_bits = 768;
if (options->login_grace_time == -1)
options->login_grace_time = 600;
if (options->key_regeneration_time == -1)
options->key_regeneration_time = 3600;
if (options->permit_root_login == -1)
options->permit_root_login = 1; /* yes */
if (options->ignore_rhosts == -1)
options->ignore_rhosts = 1;
if (options->ignore_user_known_hosts == -1)
options->ignore_user_known_hosts = 0;
if (options->check_mail == -1)
options->check_mail = 0;
if (options->print_motd == -1)
options->print_motd = 1;
if (options->x11_forwarding == -1)
options->x11_forwarding = 0;
if (options->x11_display_offset == -1)
options->x11_display_offset = 10;
#ifdef XAUTH_PATH
if (options->xauth_location == NULL)
options->xauth_location = XAUTH_PATH;
#endif /* XAUTH_PATH */
if (options->strict_modes == -1)
options->strict_modes = 1;
if (options->keepalives == -1)
options->keepalives = 1;
if (options->log_facility == (SyslogFacility) (-1))
options->log_facility = SYSLOG_FACILITY_AUTH;
if (options->log_level == (LogLevel) (-1))
options->log_level = SYSLOG_LEVEL_INFO;
if (options->rhosts_authentication == -1)
options->rhosts_authentication = 0;
if (options->rhosts_rsa_authentication == -1)
options->rhosts_rsa_authentication = 0;
if (options->rsa_authentication == -1)
options->rsa_authentication = 1;
if (options->pubkey_authentication == -1)
options->pubkey_authentication = 1;
#ifdef KRB4
if (options->kerberos_authentication == -1)
options->kerberos_authentication = (access(KEYFILE, R_OK) == 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;
#endif /* KRB4 */
#ifdef AFS
if (options->kerberos_tgt_passing == -1)
options->kerberos_tgt_passing = 0;
if (options->afs_token_passing == -1)
options->afs_token_passing = k_hasafs();
#endif /* AFS */
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
options->kbd_interactive_authentication = 0;
if (options->challenge_reponse_authentication == -1)
options->challenge_reponse_authentication = 1;
if (options->permit_empty_passwd == -1)
options->permit_empty_passwd = 0;
if (options->use_login == -1)
options->use_login = 0;
if (options->allow_tcp_forwarding == -1)
options->allow_tcp_forwarding = 1;
if (options->gateway_ports == -1)
options->gateway_ports = 0;
if (options->max_startups == -1)
options->max_startups = 10;
if (options->max_startups_rate == -1)
options->max_startups_rate = 100; /* 100% */
if (options->max_startups_begin == -1)
options->max_startups_begin = options->max_startups;
}
/* Keyword tokens. */
typedef enum {
sBadOption, /* == unknown option */
sPort, sHostKeyFile, sServerKeyBits, sLoginGraceTime, sKeyRegenerationTime,
sPermitRootLogin, sLogFacility, sLogLevel,
sRhostsAuthentication, sRhostsRSAAuthentication, sRSAAuthentication,
#ifdef KRB4
sKerberosAuthentication, sKerberosOrLocalPasswd, sKerberosTicketCleanup,
#endif
#ifdef AFS
sKerberosTgtPassing, sAFSTokenPassing,
#endif
sChallengeResponseAuthentication,
sPasswordAuthentication, sKbdInteractiveAuthentication, sListenAddress,
sPrintMotd, sIgnoreRhosts, sX11Forwarding, sX11DisplayOffset,
sStrictModes, sEmptyPasswd, sRandomSeedFile, sKeepAlives, sCheckMail,
sUseLogin, sAllowTcpForwarding,
sAllowUsers, sDenyUsers, sAllowGroups, sDenyGroups,
sIgnoreUserKnownHosts, sCiphers, sProtocol, sPidFile,
sGatewayPorts, sPubkeyAuthentication, sXAuthLocation, sSubsystem, sMaxStartups,
sBanner
} ServerOpCodes;
/* Textual representation of the tokens. */
static struct {
const char *name;
ServerOpCodes opcode;
} keywords[] = {
{ "port", sPort },
{ "hostkey", sHostKeyFile },
{ "hostdsakey", sHostKeyFile }, /* alias */
{ "pidfile", sPidFile },
{ "serverkeybits", sServerKeyBits },
{ "logingracetime", sLoginGraceTime },
{ "keyregenerationinterval", sKeyRegenerationTime },
{ "permitrootlogin", sPermitRootLogin },
{ "syslogfacility", sLogFacility },
{ "loglevel", sLogLevel },
{ "rhostsauthentication", sRhostsAuthentication },
{ "rhostsrsaauthentication", sRhostsRSAAuthentication },
{ "rsaauthentication", sRSAAuthentication },
{ "pubkeyauthentication", sPubkeyAuthentication },
{ "dsaauthentication", sPubkeyAuthentication }, /* alias */
#ifdef KRB4
{ "kerberosauthentication", sKerberosAuthentication },
{ "kerberosorlocalpasswd", sKerberosOrLocalPasswd },
{ "kerberosticketcleanup", sKerberosTicketCleanup },
#endif
#ifdef AFS
{ "kerberostgtpassing", sKerberosTgtPassing },
{ "afstokenpassing", sAFSTokenPassing },
#endif
{ "passwordauthentication", sPasswordAuthentication },
{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication },
{ "challengeresponseauthentication", sChallengeResponseAuthentication },
{ "skeyauthentication", sChallengeResponseAuthentication }, /* alias */
{ "checkmail", sCheckMail },
{ "listenaddress", sListenAddress },
{ "printmotd", sPrintMotd },
{ "ignorerhosts", sIgnoreRhosts },
{ "ignoreuserknownhosts", sIgnoreUserKnownHosts },
{ "x11forwarding", sX11Forwarding },
{ "x11displayoffset", sX11DisplayOffset },
{ "xauthlocation", sXAuthLocation },
{ "strictmodes", sStrictModes },
{ "permitemptypasswords", sEmptyPasswd },
{ "uselogin", sUseLogin },
{ "randomseed", sRandomSeedFile },
{ "keepalive", sKeepAlives },
{ "allowtcpforwarding", sAllowTcpForwarding },
{ "allowusers", sAllowUsers },
{ "denyusers", sDenyUsers },
{ "allowgroups", sAllowGroups },
{ "denygroups", sDenyGroups },
{ "ciphers", sCiphers },
{ "protocol", sProtocol },
{ "gatewayports", sGatewayPorts },
{ "subsystem", sSubsystem },
{ "maxstartups", sMaxStartups },
{ "banner", sBanner },
{ NULL, 0 }
};
/*
* Returns the number of the token pointed to by cp of length len. Never
* returns if the token is not known.
*/
static ServerOpCodes
parse_token(const char *cp, const char *filename,
int linenum)
{
u_int i;
for (i = 0; keywords[i].name; i++)
if (strcasecmp(cp, keywords[i].name) == 0)
return keywords[i].opcode;
fprintf(stderr, "%s: line %d: Bad configuration option: %s\n",
filename, linenum, cp);
return sBadOption;
}
/*
* add listen address
*/
void
add_listen_addr(ServerOptions *options, char *addr)
{
struct addrinfo hints, *ai, *aitop;
char strport[NI_MAXSERV];
int gaierr;
int i;
if (options->num_ports == 0)
options->ports[options->num_ports++] = SSH_DEFAULT_PORT;
for (i = 0; i < options->num_ports; i++) {
memset(&hints, 0, sizeof(hints));
hints.ai_family = IPv4or6;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = (addr == NULL) ? AI_PASSIVE : 0;
snprintf(strport, sizeof strport, "%d", options->ports[i]);
if ((gaierr = getaddrinfo(addr, strport, &hints, &aitop)) != 0)
fatal("bad addr or host: %s (%s)\n",
addr ? addr : "<NULL>",
gai_strerror(gaierr));
for (ai = aitop; ai->ai_next; ai = ai->ai_next)
;
ai->ai_next = options->listen_addrs;
options->listen_addrs = aitop;
}
}
/* Reads the server configuration file. */
void
read_server_config(ServerOptions *options, const char *filename)
{
FILE *f;
char line[1024];
char *cp, **charptr, *arg;
int linenum, *intptr, value;
int bad_options = 0;
ServerOpCodes opcode;
int i;
f = fopen(filename, "r");
if (!f) {
perror(filename);
exit(1);
}
linenum = 0;
while (fgets(line, sizeof(line), f)) {
linenum++;
cp = line;
arg = strdelim(&cp);
/* Ignore leading whitespace */
if (*arg == '\0')
arg = strdelim(&cp);
if (!arg || !*arg || *arg == '#')
continue;
intptr = NULL;
charptr = NULL;
opcode = parse_token(arg, filename, linenum);
switch (opcode) {
case sBadOption:
bad_options++;
continue;
case sPort:
/* ignore ports from configfile if cmdline specifies ports */
if (options->ports_from_cmdline)
continue;
if (options->listen_addrs != NULL)
fatal("%s line %d: ports must be specified before "
"ListenAdress.\n", filename, linenum);
if (options->num_ports >= MAX_PORTS)
fatal("%s line %d: too many ports.\n",
filename, linenum);
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: missing port number.\n",
filename, linenum);
options->ports[options->num_ports++] = atoi(arg);
break;
case sServerKeyBits:
intptr = &options->server_key_bits;
parse_int:
arg = strdelim(&cp);
if (!arg || *arg == '\0') {
fprintf(stderr, "%s line %d: missing integer value.\n",
filename, linenum);
exit(1);
}
value = atoi(arg);
if (*intptr == -1)
*intptr = value;
break;
case sLoginGraceTime:
intptr = &options->login_grace_time;
goto parse_int;
case sKeyRegenerationTime:
intptr = &options->key_regeneration_time;
goto parse_int;
case sListenAddress:
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: missing inet addr.\n",
filename, linenum);
add_listen_addr(options, arg);
break;
case sHostKeyFile:
intptr = &options->num_host_key_files;
if (*intptr >= MAX_HOSTKEYS) {
fprintf(stderr, "%s line %d: to many host keys specified (max %d).\n",
filename, linenum, MAX_HOSTKEYS);
exit(1);
}
charptr = &options->host_key_files[*intptr];
parse_filename:
arg = strdelim(&cp);
if (!arg || *arg == '\0') {
fprintf(stderr, "%s line %d: missing file name.\n",
filename, linenum);
exit(1);
}
if (*charptr == NULL) {
*charptr = tilde_expand_filename(arg, getuid());
/* increase optional counter */
if (intptr != NULL)
*intptr = *intptr + 1;
}
break;
case sPidFile:
charptr = &options->pid_file;
goto parse_filename;
case sRandomSeedFile:
fprintf(stderr, "%s line %d: \"randomseed\" option is obsolete.\n",
filename, linenum);
arg = strdelim(&cp);
break;
case sPermitRootLogin:
intptr = &options->permit_root_login;
arg = strdelim(&cp);
if (!arg || *arg == '\0') {
fprintf(stderr, "%s line %d: missing yes/without-password/no argument.\n",
filename, linenum);
exit(1);
}
if (strcmp(arg, "without-password") == 0)
value = 2;
else if (strcmp(arg, "yes") == 0)
value = 1;
else if (strcmp(arg, "no") == 0)
value = 0;
else {
fprintf(stderr, "%s line %d: Bad yes/without-password/no argument: %s\n",
filename, linenum, arg);
exit(1);
}
if (*intptr == -1)
*intptr = value;
break;
case sIgnoreRhosts:
intptr = &options->ignore_rhosts;
parse_flag:
arg = strdelim(&cp);
if (!arg || *arg == '\0') {
fprintf(stderr, "%s line %d: missing yes/no argument.\n",
filename, linenum);
exit(1);
}
if (strcmp(arg, "yes") == 0)
value = 1;
else if (strcmp(arg, "no") == 0)
value = 0;
else {
fprintf(stderr, "%s line %d: Bad yes/no argument: %s\n",
filename, linenum, arg);
exit(1);
}
if (*intptr == -1)
*intptr = value;
break;
case sIgnoreUserKnownHosts:
intptr = &options->ignore_user_known_hosts;
goto parse_flag;
case sRhostsAuthentication:
intptr = &options->rhosts_authentication;
goto parse_flag;
case sRhostsRSAAuthentication:
intptr = &options->rhosts_rsa_authentication;
goto parse_flag;
case sRSAAuthentication:
intptr = &options->rsa_authentication;
goto parse_flag;
case sPubkeyAuthentication:
intptr = &options->pubkey_authentication;
goto parse_flag;
#ifdef KRB4
case sKerberosAuthentication:
intptr = &options->kerberos_authentication;
goto parse_flag;
case sKerberosOrLocalPasswd:
intptr = &options->kerberos_or_local_passwd;
goto parse_flag;
case sKerberosTicketCleanup:
intptr = &options->kerberos_ticket_cleanup;
goto parse_flag;
#endif
#ifdef AFS
case sKerberosTgtPassing:
intptr = &options->kerberos_tgt_passing;
goto parse_flag;
case sAFSTokenPassing:
intptr = &options->afs_token_passing;
goto parse_flag;
#endif
case sPasswordAuthentication:
intptr = &options->password_authentication;
goto parse_flag;
case sKbdInteractiveAuthentication:
intptr = &options->kbd_interactive_authentication;
goto parse_flag;
case sCheckMail:
intptr = &options->check_mail;
goto parse_flag;
case sChallengeResponseAuthentication:
intptr = &options->challenge_reponse_authentication;
goto parse_flag;
case sPrintMotd:
intptr = &options->print_motd;
goto parse_flag;
case sX11Forwarding:
intptr = &options->x11_forwarding;
goto parse_flag;
case sX11DisplayOffset:
intptr = &options->x11_display_offset;
goto parse_int;
case sXAuthLocation:
charptr = &options->xauth_location;
goto parse_filename;
case sStrictModes:
intptr = &options->strict_modes;
goto parse_flag;
case sKeepAlives:
intptr = &options->keepalives;
goto parse_flag;
case sEmptyPasswd:
intptr = &options->permit_empty_passwd;
goto parse_flag;
case sUseLogin:
intptr = &options->use_login;
goto parse_flag;
case sGatewayPorts:
intptr = &options->gateway_ports;
goto parse_flag;
case sLogFacility:
intptr = (int *) &options->log_facility;
arg = strdelim(&cp);
value = log_facility_number(arg);
if (value == (SyslogFacility) - 1)
fatal("%.200s line %d: unsupported log facility '%s'\n",
filename, linenum, arg ? arg : "<NONE>");
if (*intptr == -1)
*intptr = (SyslogFacility) value;
break;
case sLogLevel:
intptr = (int *) &options->log_level;
arg = strdelim(&cp);
value = log_level_number(arg);
if (value == (LogLevel) - 1)
fatal("%.200s line %d: unsupported log level '%s'\n",
filename, linenum, arg ? arg : "<NONE>");
if (*intptr == -1)
*intptr = (LogLevel) value;
break;
case sAllowTcpForwarding:
intptr = &options->allow_tcp_forwarding;
goto parse_flag;
case sAllowUsers:
while ((arg = strdelim(&cp)) && *arg != '\0') {
if (options->num_allow_users >= MAX_ALLOW_USERS)
fatal("%s line %d: too many allow users.\n",
filename, linenum);
options->allow_users[options->num_allow_users++] = xstrdup(arg);
}
break;
case sDenyUsers:
while ((arg = strdelim(&cp)) && *arg != '\0') {
if (options->num_deny_users >= MAX_DENY_USERS)
fatal( "%s line %d: too many deny users.\n",
filename, linenum);
options->deny_users[options->num_deny_users++] = xstrdup(arg);
}
break;
case sAllowGroups:
while ((arg = strdelim(&cp)) && *arg != '\0') {
if (options->num_allow_groups >= MAX_ALLOW_GROUPS)
fatal("%s line %d: too many allow groups.\n",
filename, linenum);
options->allow_groups[options->num_allow_groups++] = xstrdup(arg);
}
break;
case sDenyGroups:
while ((arg = strdelim(&cp)) && *arg != '\0') {
if (options->num_deny_groups >= MAX_DENY_GROUPS)
fatal("%s line %d: too many deny groups.\n",
filename, linenum);
options->deny_groups[options->num_deny_groups++] = xstrdup(arg);
}
break;
case sCiphers:
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: Missing argument.", filename, linenum);
if (!ciphers_valid(arg))
fatal("%s line %d: Bad SSH2 cipher spec '%s'.",
filename, linenum, arg ? arg : "<NONE>");
if (options->ciphers == NULL)
options->ciphers = xstrdup(arg);
break;
case sProtocol:
intptr = &options->protocol;
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: Missing argument.", filename, linenum);
value = proto_spec(arg);
if (value == SSH_PROTO_UNKNOWN)
fatal("%s line %d: Bad protocol spec '%s'.",
filename, linenum, arg ? arg : "<NONE>");
if (*intptr == SSH_PROTO_UNKNOWN)
*intptr = value;
break;
case sSubsystem:
if(options->num_subsystems >= MAX_SUBSYSTEMS) {
fatal("%s line %d: too many subsystems defined.",
filename, linenum);
}
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: Missing subsystem name.",
filename, linenum);
for (i = 0; i < options->num_subsystems; i++)
if(strcmp(arg, options->subsystem_name[i]) == 0)
fatal("%s line %d: Subsystem '%s' already defined.",
filename, linenum, arg);
options->subsystem_name[options->num_subsystems] = xstrdup(arg);
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: Missing subsystem command.",
filename, linenum);
options->subsystem_command[options->num_subsystems] = xstrdup(arg);
options->num_subsystems++;
break;
case sMaxStartups:
arg = strdelim(&cp);
if (!arg || *arg == '\0')
fatal("%s line %d: Missing MaxStartups spec.",
filename, linenum);
if (sscanf(arg, "%d:%d:%d",
&options->max_startups_begin,
&options->max_startups_rate,
&options->max_startups) == 3) {
if (options->max_startups_begin >
options->max_startups ||
options->max_startups_rate > 100 ||
options->max_startups_rate < 1)
fatal("%s line %d: Illegal MaxStartups spec.",
filename, linenum);
break;
}
intptr = &options->max_startups;
goto parse_int;
case sBanner:
charptr = &options->banner;
goto parse_filename;
default:
fprintf(stderr, "%s line %d: Missing handler for opcode %s (%d)\n",
filename, linenum, arg, opcode);
exit(1);
}
if ((arg = strdelim(&cp)) != NULL && *arg != '\0') {
fprintf(stderr,
"%s line %d: garbage at end of line; \"%.200s\".\n",
filename, linenum, arg);
exit(1);
}
}
fclose(f);
if (bad_options > 0) {
fprintf(stderr, "%s: terminating, %d bad configuration options\n",
filename, bad_options);
exit(1);
}
}