sonic-openssh/readconf.c

709 строки
19 KiB
C

/*
*
* readconf.c
*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* Created: Sat Apr 22 00:03:10 1995 ylo
*
* Functions for reading the configuration files.
*
*/
#include "includes.h"
RCSID("$Id: readconf.c,v 1.7 1999/12/06 00:47:29 damien Exp $");
#include "ssh.h"
#include "cipher.h"
#include "readconf.h"
#include "xmalloc.h"
/* Format of the configuration file:
# Configuration data is parsed as follows:
# 1. command line options
# 2. user-specific file
# 3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.
# Host-specific declarations. These may override anything above. A single
# host may match multiple declarations; these are processed in the order
# that they are given in.
Host *.ngs.fi ngs.fi
FallBackToRsh no
Host fake.com
HostName another.host.name.real.org
User blaah
Port 34289
ForwardX11 no
ForwardAgent no
Host books.com
RemoteForward 9999 shadows.cs.hut.fi:9999
Cipher 3des
Host fascist.blob.com
Port 23123
User tylonen
RhostsAuthentication no
PasswordAuthentication no
Host puukko.hut.fi
User t35124p
ProxyCommand ssh-proxy %h %p
Host *.fr
UseRsh yes
Host *.su
Cipher none
PasswordAuthentication no
# Defaults for various options
Host *
ForwardAgent no
ForwardX11 yes
RhostsAuthentication yes
PasswordAuthentication yes
RSAAuthentication yes
RhostsRSAAuthentication yes
FallBackToRsh no
UseRsh no
StrictHostKeyChecking yes
KeepAlives no
IdentityFile ~/.ssh/identity
Port 22
EscapeChar ~
*/
/* Keyword tokens. */
typedef enum {
oBadOption,
oForwardAgent, oForwardX11, oGatewayPorts, oRhostsAuthentication,
oPasswordAuthentication, oRSAAuthentication, oFallBackToRsh, oUseRsh,
oSkeyAuthentication,
#ifdef KRB4
oKerberosAuthentication,
#endif /* KRB4 */
#ifdef AFS
oKerberosTgtPassing, oAFSTokenPassing,
#endif
oIdentityFile, oHostName, oPort, oCipher, oRemoteForward, oLocalForward,
oUser, oHost, oEscapeChar, oRhostsRSAAuthentication, oProxyCommand,
oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts,
oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression,
oCompressionLevel, oKeepAlives, oNumberOfPasswordPrompts, oTISAuthentication,
oUsePrivilegedPort, oLogLevel
} OpCodes;
/* Textual representations of the tokens. */
static struct {
const char *name;
OpCodes opcode;
} keywords[] = {
{ "forwardagent", oForwardAgent },
{ "forwardx11", oForwardX11 },
{ "gatewayports", oGatewayPorts },
{ "useprivilegedport", oUsePrivilegedPort },
{ "rhostsauthentication", oRhostsAuthentication },
{ "passwordauthentication", oPasswordAuthentication },
{ "rsaauthentication", oRSAAuthentication },
{ "skeyauthentication", oSkeyAuthentication },
#ifdef KRB4
{ "kerberosauthentication", oKerberosAuthentication },
#endif /* KRB4 */
#ifdef AFS
{ "kerberostgtpassing", oKerberosTgtPassing },
{ "afstokenpassing", oAFSTokenPassing },
#endif
{ "fallbacktorsh", oFallBackToRsh },
{ "usersh", oUseRsh },
{ "identityfile", oIdentityFile },
{ "hostname", oHostName },
{ "proxycommand", oProxyCommand },
{ "port", oPort },
{ "cipher", oCipher },
{ "remoteforward", oRemoteForward },
{ "localforward", oLocalForward },
{ "user", oUser },
{ "host", oHost },
{ "escapechar", oEscapeChar },
{ "rhostsrsaauthentication", oRhostsRSAAuthentication },
{ "globalknownhostsfile", oGlobalKnownHostsFile },
{ "userknownhostsfile", oUserKnownHostsFile },
{ "connectionattempts", oConnectionAttempts },
{ "batchmode", oBatchMode },
{ "checkhostip", oCheckHostIP },
{ "stricthostkeychecking", oStrictHostKeyChecking },
{ "compression", oCompression },
{ "compressionlevel", oCompressionLevel },
{ "keepalive", oKeepAlives },
{ "numberofpasswordprompts", oNumberOfPasswordPrompts },
{ "tisauthentication", oTISAuthentication },
{ "loglevel", oLogLevel },
{ NULL, 0 }
};
/* Characters considered whitespace in strtok calls. */
#define WHITESPACE " \t\r\n"
/*
* Adds a local TCP/IP port forward to options. Never returns if there is an
* error.
*/
void
add_local_forward(Options *options, u_short port, const char *host,
u_short host_port)
{
Forward *fwd;
extern uid_t original_real_uid;
if (port < IPPORT_RESERVED && original_real_uid != 0)
fatal("Privileged ports can only be forwarded by root.\n");
if (options->num_local_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
fatal("Too many local forwards (max %d).", SSH_MAX_FORWARDS_PER_DIRECTION);
fwd = &options->local_forwards[options->num_local_forwards++];
fwd->port = port;
fwd->host = xstrdup(host);
fwd->host_port = host_port;
}
/*
* Adds a remote TCP/IP port forward to options. Never returns if there is
* an error.
*/
void
add_remote_forward(Options *options, u_short port, const char *host,
u_short host_port)
{
Forward *fwd;
if (options->num_remote_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
fatal("Too many remote forwards (max %d).",
SSH_MAX_FORWARDS_PER_DIRECTION);
fwd = &options->remote_forwards[options->num_remote_forwards++];
fwd->port = port;
fwd->host = xstrdup(host);
fwd->host_port = host_port;
}
/*
* Returns the number of the token pointed to by cp of length len. Never
* returns if the token is not known.
*/
static OpCodes
parse_token(const char *cp, const char *filename, int linenum)
{
unsigned 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 oBadOption;
}
/*
* Processes a single option line as used in the configuration files. This
* only sets those values that have not already been set.
*/
int
process_config_line(Options *options, const char *host,
char *line, const char *filename, int linenum,
int *activep)
{
char buf[256], *cp, *string, **charptr, *cp2;
int opcode, *intptr, value;
u_short fwd_port, fwd_host_port;
/* Skip leading whitespace. */
cp = line + strspn(line, WHITESPACE);
if (!*cp || *cp == '\n' || *cp == '#')
return 0;
/* Get the keyword. (Each line is supposed to begin with a keyword). */
cp = strtok(cp, WHITESPACE);
opcode = parse_token(cp, filename, linenum);
switch (opcode) {
case oBadOption:
/* don't panic, but count bad options */
return -1;
/* NOTREACHED */
case oForwardAgent:
intptr = &options->forward_agent;
parse_flag:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing yes/no argument.", filename, linenum);
value = 0; /* To avoid compiler warning... */
if (strcmp(cp, "yes") == 0 || strcmp(cp, "true") == 0)
value = 1;
else if (strcmp(cp, "no") == 0 || strcmp(cp, "false") == 0)
value = 0;
else
fatal("%.200s line %d: Bad yes/no argument.", filename, linenum);
if (*activep && *intptr == -1)
*intptr = value;
break;
case oForwardX11:
intptr = &options->forward_x11;
goto parse_flag;
case oGatewayPorts:
intptr = &options->gateway_ports;
goto parse_flag;
case oUsePrivilegedPort:
intptr = &options->use_privileged_port;
goto parse_flag;
case oRhostsAuthentication:
intptr = &options->rhosts_authentication;
goto parse_flag;
case oPasswordAuthentication:
intptr = &options->password_authentication;
goto parse_flag;
case oRSAAuthentication:
intptr = &options->rsa_authentication;
goto parse_flag;
case oRhostsRSAAuthentication:
intptr = &options->rhosts_rsa_authentication;
goto parse_flag;
case oTISAuthentication:
/* fallthrough, there is no difference on the client side */
case oSkeyAuthentication:
intptr = &options->skey_authentication;
goto parse_flag;
#ifdef KRB4
case oKerberosAuthentication:
intptr = &options->kerberos_authentication;
goto parse_flag;
#endif /* KRB4 */
#ifdef AFS
case oKerberosTgtPassing:
intptr = &options->kerberos_tgt_passing;
goto parse_flag;
case oAFSTokenPassing:
intptr = &options->afs_token_passing;
goto parse_flag;
#endif
case oFallBackToRsh:
intptr = &options->fallback_to_rsh;
goto parse_flag;
case oUseRsh:
intptr = &options->use_rsh;
goto parse_flag;
case oBatchMode:
intptr = &options->batch_mode;
goto parse_flag;
case oCheckHostIP:
intptr = &options->check_host_ip;
goto parse_flag;
case oStrictHostKeyChecking:
intptr = &options->strict_host_key_checking;
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing yes/no argument.",
filename, linenum);
value = 0; /* To avoid compiler warning... */
if (strcmp(cp, "yes") == 0 || strcmp(cp, "true") == 0)
value = 1;
else if (strcmp(cp, "no") == 0 || strcmp(cp, "false") == 0)
value = 0;
else if (strcmp(cp, "ask") == 0)
value = 2;
else
fatal("%.200s line %d: Bad yes/no/ask argument.", filename, linenum);
if (*activep && *intptr == -1)
*intptr = value;
break;
case oCompression:
intptr = &options->compression;
goto parse_flag;
case oKeepAlives:
intptr = &options->keepalives;
goto parse_flag;
case oNumberOfPasswordPrompts:
intptr = &options->number_of_password_prompts;
goto parse_int;
case oCompressionLevel:
intptr = &options->compression_level;
goto parse_int;
case oIdentityFile:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (*activep) {
if (options->num_identity_files >= SSH_MAX_IDENTITY_FILES)
fatal("%.200s line %d: Too many identity files specified (max %d).",
filename, linenum, SSH_MAX_IDENTITY_FILES);
options->identity_files[options->num_identity_files++] = xstrdup(cp);
}
break;
case oUser:
charptr = &options->user;
parse_string:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (*activep && *charptr == NULL)
*charptr = xstrdup(cp);
break;
case oGlobalKnownHostsFile:
charptr = &options->system_hostfile;
goto parse_string;
case oUserKnownHostsFile:
charptr = &options->user_hostfile;
goto parse_string;
case oHostName:
charptr = &options->hostname;
goto parse_string;
case oProxyCommand:
charptr = &options->proxy_command;
string = xstrdup("");
while ((cp = strtok(NULL, WHITESPACE)) != NULL) {
string = xrealloc(string, strlen(string) + strlen(cp) + 2);
strcat(string, " ");
strcat(string, cp);
}
if (*activep && *charptr == NULL)
*charptr = string;
else
xfree(string);
return 0;
case oPort:
intptr = &options->port;
parse_int:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (cp[0] < '0' || cp[0] > '9')
fatal("%.200s line %d: Bad number.", filename, linenum);
/* Octal, decimal, or hex format? */
value = strtol(cp, &cp2, 0);
if (cp == cp2)
fatal("%.200s line %d: Bad number.", filename, linenum);
if (*activep && *intptr == -1)
*intptr = value;
break;
case oConnectionAttempts:
intptr = &options->connection_attempts;
goto parse_int;
case oCipher:
intptr = &options->cipher;
cp = strtok(NULL, WHITESPACE);
value = cipher_number(cp);
if (value == -1)
fatal("%.200s line %d: Bad cipher '%s'.",
filename, linenum, cp ? cp : "<NONE>");
if (*activep && *intptr == -1)
*intptr = value;
break;
case oLogLevel:
intptr = (int *) &options->log_level;
cp = strtok(NULL, WHITESPACE);
value = log_level_number(cp);
if (value == (LogLevel) - 1)
fatal("%.200s line %d: unsupported log level '%s'\n",
filename, linenum, cp ? cp : "<NONE>");
if (*activep && (LogLevel) * intptr == -1)
*intptr = (LogLevel) value;
break;
case oRemoteForward:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (cp[0] < '0' || cp[0] > '9')
fatal("%.200s line %d: Badly formatted port number.",
filename, linenum);
fwd_port = atoi(cp);
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing second argument.",
filename, linenum);
if (sscanf(cp, "%255[^:]:%hu", buf, &fwd_host_port) != 2)
fatal("%.200s line %d: Badly formatted host:port.",
filename, linenum);
if (*activep)
add_remote_forward(options, fwd_port, buf, fwd_host_port);
break;
case oLocalForward:
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (cp[0] < '0' || cp[0] > '9')
fatal("%.200s line %d: Badly formatted port number.",
filename, linenum);
fwd_port = atoi(cp);
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing second argument.",
filename, linenum);
if (sscanf(cp, "%255[^:]:%hu", buf, &fwd_host_port) != 2)
fatal("%.200s line %d: Badly formatted host:port.",
filename, linenum);
if (*activep)
add_local_forward(options, fwd_port, buf, fwd_host_port);
break;
case oHost:
*activep = 0;
while ((cp = strtok(NULL, WHITESPACE)) != NULL)
if (match_pattern(host, cp)) {
debug("Applying options for %.100s", cp);
*activep = 1;
break;
}
/* Avoid garbage check below, as strtok already returned NULL. */
return 0;
case oEscapeChar:
intptr = &options->escape_char;
cp = strtok(NULL, WHITESPACE);
if (!cp)
fatal("%.200s line %d: Missing argument.", filename, linenum);
if (cp[0] == '^' && cp[2] == 0 &&
(unsigned char) cp[1] >= 64 && (unsigned char) cp[1] < 128)
value = (unsigned char) cp[1] & 31;
else if (strlen(cp) == 1)
value = (unsigned char) cp[0];
else if (strcmp(cp, "none") == 0)
value = -2;
else {
fatal("%.200s line %d: Bad escape character.",
filename, linenum);
/* NOTREACHED */
value = 0; /* Avoid compiler warning. */
}
if (*activep && *intptr == -1)
*intptr = value;
break;
default:
fatal("process_config_line: Unimplemented opcode %d", opcode);
}
/* Check that there is no garbage at end of line. */
if (strtok(NULL, WHITESPACE) != NULL)
fatal("%.200s line %d: garbage at end of line.",
filename, linenum);
return 0;
}
/*
* Reads the config file and modifies the options accordingly. Options
* should already be initialized before this call. This never returns if
* there is an error. If the file does not exist, this returns immediately.
*/
void
read_config_file(const char *filename, const char *host, Options *options)
{
FILE *f;
char line[1024];
int active, linenum;
int bad_options = 0;
/* Open the file. */
f = fopen(filename, "r");
if (!f)
return;
debug("Reading configuration data %.200s", filename);
/*
* Mark that we are now processing the options. This flag is turned
* on/off by Host specifications.
*/
active = 1;
linenum = 0;
while (fgets(line, sizeof(line), f)) {
/* Update line number counter. */
linenum++;
if (process_config_line(options, host, line, filename, linenum, &active) != 0)
bad_options++;
}
fclose(f);
if (bad_options > 0)
fatal("%s: terminating, %d bad configuration options\n",
filename, bad_options);
}
/*
* Initializes options to special values that indicate that they have not yet
* been set. Read_config_file will only set options with this value. Options
* are processed in the following order: command line, user config file,
* system config file. Last, fill_default_options is called.
*/
void
initialize_options(Options * options)
{
memset(options, 'X', sizeof(*options));
options->forward_agent = -1;
options->forward_x11 = -1;
options->gateway_ports = -1;
options->use_privileged_port = -1;
options->rhosts_authentication = -1;
options->rsa_authentication = -1;
options->skey_authentication = -1;
#ifdef KRB4
options->kerberos_authentication = -1;
#endif
#ifdef AFS
options->kerberos_tgt_passing = -1;
options->afs_token_passing = -1;
#endif
options->password_authentication = -1;
options->rhosts_rsa_authentication = -1;
options->fallback_to_rsh = -1;
options->use_rsh = -1;
options->batch_mode = -1;
options->check_host_ip = -1;
options->strict_host_key_checking = -1;
options->compression = -1;
options->keepalives = -1;
options->compression_level = -1;
options->port = -1;
options->connection_attempts = -1;
options->number_of_password_prompts = -1;
options->cipher = -1;
options->num_identity_files = 0;
options->hostname = NULL;
options->proxy_command = NULL;
options->user = NULL;
options->escape_char = -1;
options->system_hostfile = NULL;
options->user_hostfile = NULL;
options->num_local_forwards = 0;
options->num_remote_forwards = 0;
options->log_level = (LogLevel) - 1;
}
/*
* Called after processing other sources of option data, this fills those
* options for which no value has been specified with their default values.
*/
void
fill_default_options(Options * options)
{
if (options->forward_agent == -1)
options->forward_agent = 1;
if (options->forward_x11 == -1)
options->forward_x11 = 1;
if (options->gateway_ports == -1)
options->gateway_ports = 0;
if (options->use_privileged_port == -1)
options->use_privileged_port = 1;
if (options->rhosts_authentication == -1)
options->rhosts_authentication = 1;
if (options->rsa_authentication == -1)
options->rsa_authentication = 1;
if (options->skey_authentication == -1)
options->skey_authentication = 0;
#ifdef KRB4
if (options->kerberos_authentication == -1)
options->kerberos_authentication = 1;
#endif /* KRB4 */
#ifdef AFS
if (options->kerberos_tgt_passing == -1)
options->kerberos_tgt_passing = 1;
if (options->afs_token_passing == -1)
options->afs_token_passing = 1;
#endif /* AFS */
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->rhosts_rsa_authentication == -1)
options->rhosts_rsa_authentication = 1;
if (options->fallback_to_rsh == -1)
options->fallback_to_rsh = 1;
if (options->use_rsh == -1)
options->use_rsh = 0;
if (options->batch_mode == -1)
options->batch_mode = 0;
if (options->check_host_ip == -1)
options->check_host_ip = 1;
if (options->strict_host_key_checking == -1)
options->strict_host_key_checking = 2; /* 2 is default */
if (options->compression == -1)
options->compression = 0;
if (options->keepalives == -1)
options->keepalives = 1;
if (options->compression_level == -1)
options->compression_level = 6;
if (options->port == -1)
options->port = 0; /* Filled in ssh_connect. */
if (options->connection_attempts == -1)
options->connection_attempts = 4;
if (options->number_of_password_prompts == -1)
options->number_of_password_prompts = 3;
/* Selected in ssh_login(). */
if (options->cipher == -1)
options->cipher = SSH_CIPHER_NOT_SET;
if (options->num_identity_files == 0) {
options->identity_files[0] =
xmalloc(2 + strlen(SSH_CLIENT_IDENTITY) + 1);
sprintf(options->identity_files[0], "~/%.100s", SSH_CLIENT_IDENTITY);
options->num_identity_files = 1;
}
if (options->escape_char == -1)
options->escape_char = '~';
if (options->system_hostfile == NULL)
options->system_hostfile = SSH_SYSTEM_HOSTFILE;
if (options->user_hostfile == NULL)
options->user_hostfile = SSH_USER_HOSTFILE;
if (options->log_level == (LogLevel) - 1)
options->log_level = SYSLOG_LEVEL_INFO;
/* options->proxy_command should not be set by default */
/* options->user will be set in the main program if appropriate */
/* options->hostname will be set in the main program if appropriate */
}