/* * * readconf.c * * Author: Tatu Ylonen * * Copyright (c) 1995 Tatu Ylonen , 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 1.27 2000/04/26 20:56:29 markus Exp $"); #include "ssh.h" #include "cipher.h" #include "readconf.h" #include "match.h" #include "xmalloc.h" #include "compat.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, oCiphers, oProtocol, oIdentityFile2, oGlobalKnownHostsFile2, oUserKnownHostsFile2 } 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 }, { "identityfile2", oIdentityFile2 }, { "hostname", oHostName }, { "proxycommand", oProxyCommand }, { "port", oPort }, { "cipher", oCipher }, { "ciphers", oCiphers }, { "protocol", oProtocol }, { "remoteforward", oRemoteForward }, { "localforward", oLocalForward }, { "user", oUser }, { "host", oHost }, { "escapechar", oEscapeChar }, { "rhostsrsaauthentication", oRhostsRSAAuthentication }, { "globalknownhostsfile", oGlobalKnownHostsFile }, { "userknownhostsfile", oUserKnownHostsFile }, { "globalknownhostsfile2", oGlobalKnownHostsFile2 }, { "userknownhostsfile2", oUserKnownHostsFile2 }, { "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: case oIdentityFile2: cp = strtok(NULL, WHITESPACE); if (!cp) fatal("%.200s line %d: Missing argument.", filename, linenum); if (*activep) { intptr = (opcode == oIdentityFile) ? &options->num_identity_files : &options->num_identity_files2; if (*intptr >= SSH_MAX_IDENTITY_FILES) fatal("%.200s line %d: Too many identity files specified (max %d).", filename, linenum, SSH_MAX_IDENTITY_FILES); charptr = (opcode == oIdentityFile) ? &options->identity_files[*intptr] : &options->identity_files2[*intptr]; *charptr = xstrdup(cp); *intptr = *intptr + 1; } 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 oGlobalKnownHostsFile2: charptr = &options->system_hostfile2; goto parse_string; case oUserKnownHostsFile2: charptr = &options->user_hostfile2; 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 : ""); if (*activep && *intptr == -1) *intptr = value; break; case oCiphers: cp = strtok(NULL, WHITESPACE); if (!ciphers_valid(cp)) fatal("%.200s line %d: Bad cipher spec '%s'.", filename, linenum, cp ? cp : ""); if (*activep && options->ciphers == NULL) options->ciphers = xstrdup(cp); break; case oProtocol: intptr = &options->protocol; cp = strtok(NULL, WHITESPACE); value = proto_spec(cp); if (value == SSH_PROTO_UNKNOWN) fatal("%.200s line %d: Bad protocol spec '%s'.", filename, linenum, cp ? cp : ""); if (*activep && *intptr == SSH_PROTO_UNKNOWN) *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 : ""); 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->ciphers = NULL; options->protocol = SSH_PROTO_UNKNOWN; options->num_identity_files = 0; options->num_identity_files2 = 0; options->hostname = NULL; options->proxy_command = NULL; options->user = NULL; options->escape_char = -1; options->system_hostfile = NULL; options->user_hostfile = NULL; options->system_hostfile2 = NULL; options->user_hostfile2 = 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 = 0; 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->protocol == SSH_PROTO_UNKNOWN) options->protocol = SSH_PROTO_1; 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 0 if (options->num_identity_files2 == 0) { options->identity_files2[0] = xmalloc(2 + strlen(SSH2_CLIENT_IDENTITY) + 1); sprintf(options->identity_files2[0], "~/%.100s", SSH2_CLIENT_IDENTITY); options->num_identity_files2 = 1; } #endif 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->system_hostfile2 == NULL) options->system_hostfile2 = SSH_SYSTEM_HOSTFILE2; if (options->user_hostfile2 == NULL) options->user_hostfile2 = SSH_USER_HOSTFILE2; 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 */ }