routerparse.c

关于tor匿名通信的源代码

/* Copyright (c) 2001 Matej Pfajfar.
 * Copyright (c) 2001-2004, Roger Dingledine.
 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 * Copyright (c) 2007-2008, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/* $Id$ */
const char routerparse_c_id[] =
  "$Id$";

/**
 * \file routerparse.c
 * \brief Code to parse and validate router descriptors and directories.
 **/

#include "or.h"
#include "memarea.h"

/****************************************************************************/

/** Enumeration of possible token types.  The ones starting with K_ correspond
 * to directory 'keywords'. _ERR is an error in the tokenizing process, _EOF
 * is an end-of-file marker, and _NIL is used to encode not-a-token.
 */
typedef enum {
  K_ACCEPT = 0,
  K_DIRECTORY_SIGNATURE,
  K_RECOMMENDED_SOFTWARE,
  K_REJECT,
  K_ROUTER,
  K_SIGNED_DIRECTORY,
  K_SIGNING_KEY,
  K_ONION_KEY,
  K_ROUTER_SIGNATURE,
  K_PUBLISHED,
  K_RUNNING_ROUTERS,
  K_ROUTER_STATUS,
  K_PLATFORM,
  K_OPT,
  K_BANDWIDTH,
  K_PORTS,
  K_CONTACT,
  K_NETWORK_STATUS,
  K_UPTIME,
  K_DIR_SIGNING_KEY,
  K_FAMILY,
  K_FINGERPRINT,
  K_HIBERNATING,
  K_READ_HISTORY,
  K_WRITE_HISTORY,
  K_NETWORK_STATUS_VERSION,
  K_DIR_SOURCE,
  K_DIR_OPTIONS,
  K_CLIENT_VERSIONS,
  K_SERVER_VERSIONS,
  K_R,
  K_S,
  K_V,
  K_EVENTDNS,
  K_EXTRA_INFO,
  K_EXTRA_INFO_DIGEST,
  K_CACHES_EXTRA_INFO,
  K_HIDDEN_SERVICE_DIR,

  K_DIR_KEY_CERTIFICATE_VERSION,
  K_DIR_IDENTITY_KEY,
  K_DIR_KEY_PUBLISHED,
  K_DIR_KEY_EXPIRES,
  K_DIR_KEY_CERTIFICATION,
  K_DIR_ADDRESS,

  K_VOTE_STATUS,
  K_VALID_AFTER,
  K_FRESH_UNTIL,
  K_VALID_UNTIL,
  K_VOTING_DELAY,

  K_KNOWN_FLAGS,
  K_VOTE_DIGEST,
  K_CONSENSUS_DIGEST,
  K_CONSENSUS_METHODS,
  K_CONSENSUS_METHOD,

  A_PURPOSE,
  _A_UNKNOWN,

  R_RENDEZVOUS_SERVICE_DESCRIPTOR,
  R_VERSION,
  R_PERMANENT_KEY,
  R_SECRET_ID_PART,
  R_PUBLICATION_TIME,
  R_PROTOCOL_VERSIONS,
  R_INTRODUCTION_POINTS,
  R_SIGNATURE,

  R_IPO_IDENTIFIER,
  R_IPO_IP_ADDRESS,
  R_IPO_ONION_PORT,
  R_IPO_ONION_KEY,
  R_IPO_SERVICE_KEY,

  _UNRECOGNIZED,
  _ERR,
  _EOF,
  _NIL
} directory_keyword;

#define MIN_ANNOTATION A_PURPOSE
#define MAX_ANNOTATION _A_UNKNOWN

/** Structure to hold a single directory token.
 *
 * We parse a directory by breaking it into "tokens", each consisting
 * of a keyword, a line full of arguments, and a binary object.  The
 * arguments and object are both optional, depending on the keyword
 * type.
 *
 * This structure is only allocated in memareas; do not allocate it on
 * the heap, or token_free() won't work.
 */
typedef struct directory_token_t {
  directory_keyword tp;        /**< Type of the token. */
  int n_args:30;               /**< Number of elements in args */
  char **args;                 /**< Array of arguments from keyword line. */

  char *object_type;           /**< -----BEGIN [object_type]-----*/
  size_t object_size;          /**< Bytes in object_body */
  char *object_body;           /**< Contents of object, base64-decoded. */

  crypto_pk_env_t *key;        /**< For public keys only.  Heap-allocated. */

  char *error;                 /**< For _ERR tokens only. */
} directory_token_t;

/* ********************************************************************** */

/** We use a table of rules to decide how to parse each token type. */

/** Rules for whether the keyword needs an object. */
typedef enum {
  NO_OBJ,        /**< No object, ever. */
  NEED_OBJ,      /**< Object is required. */
  NEED_KEY_1024, /**< Object is required, and must be a 1024 bit public key */
  NEED_KEY,      /**< Object is required, and must be a public key. */
  OBJ_OK,        /**< Object is optional. */
} obj_syntax;

#define AT_START 1
#define AT_END 2

/** Determines the parsing rules for a single token type. */
typedef struct token_rule_t {
  /** The string value of the keyword identifying the type of item. */
  const char *t;
  /** The corresponding directory_keyword enum. */
  directory_keyword v;
  /** Minimum number of arguments for this item */
  int min_args;
  /** Maximum number of arguments for this item */
  int max_args;
  /** If true, we concatenate all arguments for this item into a single
   * string. */
  int concat_args;
  /** Requirments on object syntax for this item. */
  obj_syntax os;
  /** Lowest number of times this item may appear in a document. */
  int min_cnt;
  /** Highest number of times this item may appear in a document. */
  int max_cnt;
  /** One or more of AT_START/AT_END to limit where the item may appear in a
   * document. */
  int pos;
  /** True iff this token is an annotation. */
  int is_annotation;
} token_rule_t;

/*
 * Helper macros to define token tables.  's' is a string, 't' is a
 * directory_keyword, 'a' is a trio of argument multiplicities, and 'o' is an
 * object syntax.
 *
 */

/** Appears to indicate the end of a table. */
#define END_OF_TABLE { NULL, _NIL, 0,0,0, NO_OBJ, 0, INT_MAX, 0, 0 }
/** An item with no restrictions: used for obsolete document types */
#define T(s,t,a,o)    { s, t, a, o, 0, INT_MAX, 0, 0 }
/** An item with no restrictions on multiplicity or location. */
#define T0N(s,t,a,o)  { s, t, a, o, 0, INT_MAX, 0, 0 }
/** An item that must appear exactly once */
#define T1(s,t,a,o)   { s, t, a, o, 1, 1, 0, 0 }
/** An item that must appear exactly once, at the start of the document */
#define T1_START(s,t,a,o)   { s, t, a, o, 1, 1, AT_START, 0 }
/** An item that must appear exactly once, at the end of the document */
#define T1_END(s,t,a,o)   { s, t, a, o, 1, 1, AT_END, 0 }
/** An item that must appear one or more times */
#define T1N(s,t,a,o)  { s, t, a, o, 1, INT_MAX, 0, 0 }
/** An item that must appear no more than once */
#define T01(s,t,a,o)  { s, t, a, o, 0, 1, 0, 0 }
/** An annotation that must appear no more than once */
#define A01(s,t,a,o)  { s, t, a, o, 0, 1, 0, 0 }

/* Argument multiplicity: any number of arguments. */
#define ARGS        0,INT_MAX,0
/* Argument multiplicity: no arguments. */
#define NO_ARGS     0,0,0
/* Argument multiplicity: concatenate all arguments. */
#define CONCAT_ARGS 1,1,1
/* Argument multiplicity: at least <b>n</b> arguments. */
#define GE(n)       n,INT_MAX,0
/* Argument multiplicity: exactly <b>n</b> arguments. */
#define EQ(n)       n,n,0

/** List of tokens allowable in router derscriptors */
static token_rule_t routerdesc_token_table[] = {
  T0N("reject",              K_REJECT,              ARGS,    NO_OBJ ),
  T0N("accept",              K_ACCEPT,              ARGS,    NO_OBJ ),
  T1_START( "router",              K_ROUTER,              GE(5),   NO_OBJ ),
  T1( "signing-key",         K_SIGNING_KEY,         NO_ARGS, NEED_KEY_1024 ),
  T1( "onion-key",           K_ONION_KEY,           NO_ARGS, NEED_KEY_1024 ),
  T1_END( "router-signature",    K_ROUTER_SIGNATURE,    NO_ARGS, NEED_OBJ ),
  T1( "published",           K_PUBLISHED,       CONCAT_ARGS, NO_OBJ ),
  T01("uptime",              K_UPTIME,              GE(1),   NO_OBJ ),
  T01("fingerprint",         K_FINGERPRINT,     CONCAT_ARGS, NO_OBJ ),
  T01("hibernating",         K_HIBERNATING,         GE(1),   NO_OBJ ),
  T01("platform",            K_PLATFORM,        CONCAT_ARGS, NO_OBJ ),
  T01("contact",             K_CONTACT,         CONCAT_ARGS, NO_OBJ ),
  T01("read-history",        K_READ_HISTORY,        ARGS,    NO_OBJ ),
  T01("write-history",       K_WRITE_HISTORY,       ARGS,    NO_OBJ ),
  T01("extra-info-digest",   K_EXTRA_INFO_DIGEST,   GE(1),   NO_OBJ ),
  T01("hidden-service-dir",  K_HIDDEN_SERVICE_DIR,  NO_ARGS, NO_OBJ ),

  T01("family",              K_FAMILY,              ARGS,    NO_OBJ ),
  T01("caches-extra-info",   K_CACHES_EXTRA_INFO,   NO_ARGS, NO_OBJ ),
  T01("eventdns",            K_EVENTDNS,            ARGS,    NO_OBJ ),

  T0N("opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  T1( "bandwidth",           K_BANDWIDTH,           GE(3),   NO_OBJ ),
  A01("@purpose",            A_PURPOSE,             GE(1),   NO_OBJ ),

  END_OF_TABLE
};

/** List of tokens allowable in extra-info documents. */
static token_rule_t extrainfo_token_table[] = {
  T1_END( "router-signature",    K_ROUTER_SIGNATURE,    NO_ARGS, NEED_OBJ ),
  T1( "published",           K_PUBLISHED,       CONCAT_ARGS, NO_OBJ ),
  T0N("opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  T01("read-history",        K_READ_HISTORY,        ARGS,    NO_OBJ ),
  T01("write-history",       K_WRITE_HISTORY,       ARGS,    NO_OBJ ),
  T1_START( "extra-info",          K_EXTRA_INFO,          GE(2),   NO_OBJ ),

  END_OF_TABLE
};

/** List of tokens allowable in the body part of v2 and v3 networkstatus
 * documents. */
static token_rule_t rtrstatus_token_table[] = {
  T1( "r",                   K_R,                   GE(8),   NO_OBJ ),
  T1( "s",                   K_S,                   ARGS,    NO_OBJ ),
  T01("v",                   K_V,               CONCAT_ARGS, NO_OBJ ),
  T0N("opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  END_OF_TABLE
};

/** List of tokens allowable in the header part of v2 networkstatus documents.
 */
static token_rule_t netstatus_token_table[] = {
  T1( "published",           K_PUBLISHED,       CONCAT_ARGS, NO_OBJ ),
  T0N("opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  T1( "contact",             K_CONTACT,         CONCAT_ARGS, NO_OBJ ),
  T1( "dir-signing-key",     K_DIR_SIGNING_KEY,  NO_ARGS,    NEED_KEY_1024 ),
  T1( "fingerprint",         K_FINGERPRINT,     CONCAT_ARGS, NO_OBJ ),
  T1_START("network-status-version", K_NETWORK_STATUS_VERSION,
                                                    GE(1),   NO_OBJ ),
  T1( "dir-source",          K_DIR_SOURCE,          GE(3),   NO_OBJ ),
  T01("dir-options",         K_DIR_OPTIONS,         ARGS,    NO_OBJ ),
  T01("client-versions",     K_CLIENT_VERSIONS, CONCAT_ARGS, NO_OBJ ),
  T01("server-versions",     K_SERVER_VERSIONS, CONCAT_ARGS, NO_OBJ ),

  END_OF_TABLE
};

/** List of tokens allowable in the footer of v1/v2 directory/networkstatus
 * footers. */
static token_rule_t dir_footer_token_table[] = {
  T1("directory-signature", K_DIRECTORY_SIGNATURE, EQ(1), NEED_OBJ ),
  END_OF_TABLE
};

/** List of tokens allowable in v1 directory headers/footers. */
static token_rule_t dir_token_table[] = {
  /* don't enforce counts; this is obsolete. */
  T( "network-status",      K_NETWORK_STATUS,      NO_ARGS, NO_OBJ ),
  T( "directory-signature", K_DIRECTORY_SIGNATURE, ARGS,    NEED_OBJ ),
  T( "recommended-software",K_RECOMMENDED_SOFTWARE,CONCAT_ARGS, NO_OBJ ),
  T( "signed-directory",    K_SIGNED_DIRECTORY,    NO_ARGS, NO_OBJ ),

  T( "running-routers",     K_RUNNING_ROUTERS,     ARGS,    NO_OBJ ),
  T( "router-status",       K_ROUTER_STATUS,       ARGS,    NO_OBJ ),
  T( "published",           K_PUBLISHED,       CONCAT_ARGS, NO_OBJ ),
  T( "opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  T( "contact",             K_CONTACT,         CONCAT_ARGS, NO_OBJ ),
  T( "dir-signing-key",     K_DIR_SIGNING_KEY,     ARGS,    OBJ_OK ),
  T( "fingerprint",         K_FINGERPRINT,     CONCAT_ARGS, NO_OBJ ),

  END_OF_TABLE
};

#define CERTIFICATE_MEMBERS                                                  \
  T1("dir-key-certificate-version", K_DIR_KEY_CERTIFICATE_VERSION,           \
                                                     GE(1),       NO_OBJ ),  \
  T1("dir-identity-key", K_DIR_IDENTITY_KEY,         NO_ARGS,     NEED_KEY ),\
  T1("dir-key-published",K_DIR_KEY_PUBLISHED,        CONCAT_ARGS, NO_OBJ),   \
  T1("dir-key-expires",  K_DIR_KEY_EXPIRES,          CONCAT_ARGS, NO_OBJ),   \
  T1("dir-signing-key",  K_DIR_SIGNING_KEY,          NO_ARGS,     NEED_KEY ),\
  T1("dir-key-certification", K_DIR_KEY_CERTIFICATION,                       \
                                                     NO_ARGS,     NEED_OBJ), \
  T01("dir-address",     K_DIR_ADDRESS,              GE(1),       NO_OBJ),

static token_rule_t dir_key_certificate_table[] = {
  CERTIFICATE_MEMBERS
  T1("fingerprint",      K_FINGERPRINT,              CONCAT_ARGS, NO_OBJ ),
  END_OF_TABLE
};

/** List of tokens allowable in rendezvous service descriptors */
static token_rule_t desc_token_table[] = {
  T1_START("rendezvous-service-descriptor", R_RENDEZVOUS_SERVICE_DESCRIPTOR,
           EQ(1), NO_OBJ),
  T1("version", R_VERSION, EQ(1), NO_OBJ),
  T1("permanent-key", R_PERMANENT_KEY, NO_ARGS, NEED_KEY_1024),
  T1("secret-id-part", R_SECRET_ID_PART, EQ(1), NO_OBJ),
  T1("publication-time", R_PUBLICATION_TIME, CONCAT_ARGS, NO_OBJ),
  T1("protocol-versions", R_PROTOCOL_VERSIONS, EQ(1), NO_OBJ),
  T01("introduction-points", R_INTRODUCTION_POINTS, NO_ARGS, NEED_OBJ),
  T1_END("signature", R_SIGNATURE, NO_ARGS, NEED_OBJ),
  END_OF_TABLE
};

/** List of tokens allowed in the (encrypted) list of introduction points of
 * rendezvous service descriptors */
static token_rule_t ipo_token_table[] = {
  T1_START("introduction-point", R_IPO_IDENTIFIER, EQ(1), NO_OBJ),
  T1("ip-address", R_IPO_IP_ADDRESS, EQ(1), NO_OBJ),
  T1("onion-port", R_IPO_ONION_PORT, EQ(1), NO_OBJ),
  T1("onion-key", R_IPO_ONION_KEY, NO_ARGS, NEED_KEY_1024),
  T1("service-key", R_IPO_SERVICE_KEY, NO_ARGS, NEED_KEY_1024),
  END_OF_TABLE
};

static token_rule_t networkstatus_token_table[] = {
  T1("network-status-version", K_NETWORK_STATUS_VERSION,
                                                   GE(1),       NO_OBJ ),
  T1("vote-status",            K_VOTE_STATUS,      GE(1),       NO_OBJ ),
  T1("published",              K_PUBLISHED,        CONCAT_ARGS, NO_OBJ ),
  T1("valid-after",            K_VALID_AFTER,      CONCAT_ARGS, NO_OBJ ),
  T1("fresh-until",            K_FRESH_UNTIL,      CONCAT_ARGS, NO_OBJ ),
  T1("valid-until",            K_VALID_UNTIL,      CONCAT_ARGS, NO_OBJ ),
  T1("voting-delay",           K_VOTING_DELAY,     GE(2),       NO_OBJ ),
  T1("known-flags",            K_KNOWN_FLAGS,      ARGS,        NO_OBJ ),
  T( "fingerprint",            K_FINGERPRINT,      CONCAT_ARGS, NO_OBJ ),

  CERTIFICATE_MEMBERS

  T0N("opt",                 K_OPT,             CONCAT_ARGS, OBJ_OK ),
  T1( "contact",             K_CONTACT,         CONCAT_ARGS, NO_OBJ ),
  T1( "dir-source",          K_DIR_SOURCE,      GE(6),       NO_OBJ ),
  T1( "known-flags",         K_KNOWN_FLAGS,     CONCAT_ARGS, NO_OBJ ),
  T01("client-versions",     K_CLIENT_VERSIONS, CONCAT_ARGS, NO_OBJ ),
  T01("server-versions",     K_SERVER_VERSIONS, CONCAT_ARGS, NO_OBJ ),
  T1( "consensus-methods",   K_CONSENSUS_METHODS, GE(1),     NO_OBJ ),

  END_OF_TABLE
};
static token_rule_t networkstatus_consensus_token_table[] = {
  T1("network-status-version", K_NETWORK_STATUS_VERSION,