Initial revision

1 files changed, 684 insertions, 0 deletions

diff --git a/readconf.c b/readconf.c
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+++ b/readconf.c
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+/*
+
+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 1.1 1999/10/27 03:42:44 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
+{
+  oForwardAgent, oForwardX11, oGatewayPorts, oRhostsAuthentication,
+  oPasswordAuthentication, oRSAAuthentication, oFallBackToRsh, oUseRsh,
+#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
+} 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 },
+#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 },
+  { 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, int port, const char *host,
+		       int host_port)
+{
+  Forward *fwd;
+  extern uid_t original_real_uid;
+  if ((port & 0xffff) != port)
+    fatal("Requested forwarding of nonexistent port %d.", port);
+  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, int port, const char *host,
+		       int 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 (strcmp(cp, keywords[i].name) == 0)
+      return keywords[i].opcode;
+
+  fatal("%.200s line %d: Bad configuration option.",
+	filename, linenum);
+  /*NOTREACHED*/
+  return 0;
+}
+
+/* Processes a single option line as used in the configuration files.
+   This only sets those values that have not already been set. */
+
+void process_config_line(Options *options, const char *host,
+			 char *line, const char *filename, int linenum,
+			 int *activep)
+{
+  char buf[256], *cp, *string, **charptr;
+  int opcode, *intptr, value, fwd_port, fwd_host_port;
+
+  /* Skip leading whitespace. */
+  cp = line + strspn(line, WHITESPACE);
+  if (!*cp || *cp == '\n' || *cp == '#')
+    return;
+
+  /* Get the keyword. (Each line is supposed to begin with a keyword). */
+  cp = strtok(cp, WHITESPACE);
+  {
+    char *t = cp;
+    for (; *t != 0; t++)
+      if ('A' <= *t && *t <= 'Z')
+	*t = *t - 'A' + 'a';	/* tolower */
+      
+  }
+  opcode = parse_token(cp, filename, linenum);
+
+  switch (opcode)
+    {
+
+    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;
+
+#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 oTISAuthentication:
+      cp = strtok(NULL, WHITESPACE);
+      if (cp != 0 && (strcmp(cp, "yes") == 0 || strcmp(cp, "true") == 0))
+	fprintf(stderr,
+		"%.99s line %d: Warning, TIS is not supported.\n",
+		filename,
+		linenum);
+      break;
+
+    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;
+
+    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);
+#if 0
+      value = atoi(cp);
+#else
+      {
+	char *ptr;
+	value = strtol(cp, &ptr, 0); /* Octal, decimal, or hex format? */
+	if (cp == ptr)
+	  fatal("%.200s line %d: Bad number.", filename, linenum);	    
+      }
+#endif
+      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.", filename, linenum);
+      if (*activep && *intptr == -1)
+	*intptr = 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[^:]:%d", 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[^:]:%d", 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;
+
+    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("parse_config_file: 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);
+}
+
+
+/* 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;
+
+  /* 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++;
+
+      process_config_line(options, host, line, filename, linenum, &active);
+    }
+  fclose(f);
+}
+
+/* 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;
+#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;
+}
+
+/* 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;
+#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;
+  if (options->cipher == -1)
+    options->cipher = SSH_CIPHER_NOT_SET; /* Selected in ssh_login(). */
+  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;
+  /* 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 */
+}
+