/* Copyright 2001,2002,2003 Roger Dingledine, Matej Pfajfar. */
/* See LICENSE for licensing information */
/* $Id$ */
#include "or.h"
/**
* \file dirserv.c
* \brief Directory server core implementation.
**/
/** How far in the future do we allow a router to get? (seconds) */
#define ROUTER_ALLOW_SKEW (30*60)
extern or_options_t options; /**< command-line and config-file options */
/** Do we need to regenerate the directory when someone asks for it? */
static int the_directory_is_dirty = 1;
static int list_running_servers(char **nicknames_out);
static void directory_remove_unrecognized(void);
/************** Fingerprint handling code ************/
typedef struct fingerprint_entry_t {
char *nickname;
char *fingerprint;
} fingerprint_entry_t;
/** List of nickname-\>identity fingerprint mappings for all the routers
* that we recognize. Used to prevent Sybil attacks. */
static smartlist_t *fingerprint_list = NULL;
/** Add the fingerprint fp for the nickname nickname to
* the global list of recognized identity key fingerprints.
*/
void /* Should be static; exposed for testing */
add_fingerprint_to_dir(const char *nickname, const char *fp)
{
int i;
fingerprint_entry_t *ent;
if (!fingerprint_list)
fingerprint_list = smartlist_create();
for (i = 0; i < smartlist_len(fingerprint_list); ++i) {
ent = smartlist_get(fingerprint_list, i);
if (!strcasecmp(ent->nickname,nickname)) {
tor_free(ent->fingerprint);
ent->fingerprint = tor_strdup(fp);
return;
}
}
ent = tor_malloc(sizeof(fingerprint_entry_t));
ent->nickname = tor_strdup(nickname);
ent->fingerprint = tor_strdup(fp);
smartlist_add(fingerprint_list, ent);
}
/** Add the nickname and fingerprint for this OR to the recognized list.
*/
int
dirserv_add_own_fingerprint(const char *nickname, crypto_pk_env_t *pk)
{
char fp[FINGERPRINT_LEN+1];
if (crypto_pk_get_fingerprint(pk, fp)<0) {
log_fn(LOG_ERR, "Error computing fingerprint");
return -1;
}
add_fingerprint_to_dir(nickname, fp);
return 0;
}
/** Parse the nickname-\>fingerprint mappings stored in the file named
* fname. The file format is line-based, with each non-blank
* holding one nickname, some space, and a fingerprint for that
* nickname. On success, replace the current fingerprint list with
* the contents of fname and return 0. On failure, leave the
* current fingerprint list untouched, and return -1. */
int
dirserv_parse_fingerprint_file(const char *fname)
{
FILE *file;
char line[FINGERPRINT_LEN+MAX_NICKNAME_LEN+20+1];
char *nickname, *fingerprint;
smartlist_t *fingerprint_list_new;
int i, result;
fingerprint_entry_t *ent;
if(!(file = fopen(fname, "r"))) {
log_fn(LOG_WARN, "Cannot open fingerprint file %s", fname);
return -1;
}
fingerprint_list_new = smartlist_create();
while( (result=parse_line_from_file(line, sizeof(line),file,&nickname,&fingerprint)) > 0) {
if (strlen(nickname) > MAX_NICKNAME_LEN) {
log(LOG_WARN, "Nickname %s too long in fingerprint file. Skipping.", nickname);
continue;
}
if(strlen(fingerprint) != FINGERPRINT_LEN ||
!crypto_pk_check_fingerprint_syntax(fingerprint)) {
log_fn(LOG_WARN, "Invalid fingerprint (nickname %s, fingerprint %s). Skipping.",
nickname, fingerprint);
continue;
}
for (i = 0; i < smartlist_len(fingerprint_list_new); ++i) {
ent = smartlist_get(fingerprint_list_new, i);
if (0==strcasecmp(ent->nickname, nickname)) {
log(LOG_WARN, "Duplicate nickname %s. Skipping.",nickname);
break; /* out of the for. the 'if' below means skip to the next line. */
}
}
if(i == smartlist_len(fingerprint_list_new)) { /* not a duplicate */
ent = tor_malloc(sizeof(fingerprint_entry_t));
ent->nickname = tor_strdup(nickname);
ent->fingerprint = tor_strdup(fingerprint);
smartlist_add(fingerprint_list_new, ent);
}
}
fclose(file);
if(result == 0) { /* eof; replace the global fingerprints list. */
dirserv_free_fingerprint_list();
fingerprint_list = fingerprint_list_new;
/* Delete any routers whose fingerprints we no longer recognize */
directory_remove_unrecognized();
return 0;
}
/* error */
log_fn(LOG_WARN, "Error reading from fingerprint file");
for (i = 0; i < smartlist_len(fingerprint_list_new); ++i) {
ent = smartlist_get(fingerprint_list_new, i);
tor_free(ent->nickname);
tor_free(ent->fingerprint);
tor_free(ent);
}
smartlist_free(fingerprint_list_new);
return -1;
}
/** Check whether router has a nickname/identity key combination that
* we recognize from the fingerprint list. Return 1 if router's
* identity and nickname match, -1 if we recognize the nickname but
* the identity key is wrong, and 0 if the nickname is not known. */
int
dirserv_router_fingerprint_is_known(const routerinfo_t *router)
{
int i, found=0;
fingerprint_entry_t *ent =NULL;
char fp[FINGERPRINT_LEN+1];
if (!fingerprint_list)
fingerprint_list = smartlist_create();
log_fn(LOG_DEBUG, "%d fingerprints known.", smartlist_len(fingerprint_list));
for (i=0;inickname, ent->nickname);
if (!strcasecmp(router->nickname,ent->nickname)) {
found = 1;
break;
}
}
if (!found) { /* No such server known */
log_fn(LOG_INFO,"no fingerprint found for %s",router->nickname);
return 0;
}
if (crypto_pk_get_fingerprint(router->identity_pkey, fp)) {
log_fn(LOG_WARN,"error computing fingerprint");
return -1;
}
if (0==strcasecmp(ent->fingerprint, fp)) {
log_fn(LOG_DEBUG,"good fingerprint for %s",router->nickname);
return 1; /* Right fingerprint. */
} else {
log_fn(LOG_WARN,"mismatched fingerprint for %s",router->nickname);
return -1; /* Wrong fingerprint. */
}
}
/** Return true iff any router named nickname is in the fingerprint
* list. */
static int
router_nickname_is_approved(const char *nickname)
{
int i;
fingerprint_entry_t *ent;
if (!fingerprint_list)
return 0;
for (i=0;inickname)) {
return 1;
}
}
return 0;
}
/** Clear the current fingerprint list. */
void
dirserv_free_fingerprint_list()
{
int i;
fingerprint_entry_t *ent;
if (!fingerprint_list)
return;
for (i = 0; i < smartlist_len(fingerprint_list); ++i) {
ent = smartlist_get(fingerprint_list, i);
tor_free(ent->nickname);
tor_free(ent->fingerprint);
tor_free(ent);
}
smartlist_free(fingerprint_list);
fingerprint_list = NULL;
}
/*
* Descriptor list
*/
/** A directory server's view of a server descriptor. Contains both
* parsed and unparsed versions. */
typedef struct descriptor_entry_t {
char *nickname;
time_t published;
size_t desc_len;
char *descriptor;
routerinfo_t *router;
} descriptor_entry_t;
/** List of all server descriptors that this dirserv is holding. */
static smartlist_t *descriptor_list = NULL;
/** Release the storage held by desc */
static void free_descriptor_entry(descriptor_entry_t *desc)
{
tor_free(desc->descriptor);
tor_free(desc->nickname);
routerinfo_free(desc->router);
free(desc);
}
/** Release all storage that the dirserv is holding for server
* descriptors. */
void
dirserv_free_descriptors()
{
if (!descriptor_list)
return;
SMARTLIST_FOREACH(descriptor_list, descriptor_entry_t *, d,
free_descriptor_entry(d));
smartlist_clear(descriptor_list);
}
/** Parse the server descriptor at *desc and maybe insert it into the
* list of service descriptors, and (if the descriptor is well-formed)
* advance *desc immediately past the descriptor's end.
*
* Return 1 if descriptor is well-formed and accepted;
* 0 if well-formed and server is unapproved;
* -1 if not well-formed or other error.
*/
int
dirserv_add_descriptor(const char **desc)
{
descriptor_entry_t *ent = NULL;
routerinfo_t *ri = NULL;
int i, r, found=-1;
char *start, *end;
char *desc_tmp = NULL;
const char *cp;
size_t desc_len;
time_t now;
if (!descriptor_list)
descriptor_list = smartlist_create();
start = strstr(*desc, "router ");
if (!start) {
log_fn(LOG_WARN, "no 'router' line found. This is not a descriptor.");
return -1;
}
if ((end = strstr(start+6, "\nrouter "))) {
++end; /* Include NL. */
} else if ((end = strstr(start+6, "\ndirectory-signature"))) {
++end;
} else {
end = start+strlen(start);
}
desc_len = end-start;
cp = desc_tmp = tor_strndup(start, desc_len);
/* Check: is the descriptor syntactically valid? */
ri = router_parse_entry_from_string(cp, NULL);
tor_free(desc_tmp);
if (!ri) {
log(LOG_WARN, "Couldn't parse descriptor");
return -1;
}
/* Okay. Now check whether the fingerprint is recognized. */
r = dirserv_router_fingerprint_is_known(ri);
if(r<1) {
if(r==0) {
char fp[FINGERPRINT_LEN+1];
log_fn(LOG_WARN, "Unknown nickname %s (%s:%d). Not adding.",
ri->nickname, ri->address, ri->or_port);
if (crypto_pk_get_fingerprint(ri->identity_pkey, fp) < 0) {
log_fn(LOG_WARN, "Error computing fingerprint for %s", ri->nickname);
} else {
log_fn(LOG_WARN, "Fingerprint line: %s %s", ri->nickname, fp);
}
} else {
log_fn(LOG_WARN, "Known nickname %s, wrong fingerprint. Not adding.", ri->nickname);
}
routerinfo_free(ri);
*desc = end;
return 0;
}
/* Is there too much clock skew? */
now = time(NULL);
if (ri->published_on > now+ROUTER_ALLOW_SKEW) {
log_fn(LOG_WARN, "Publication time for nickname %s is too far in the future; possible clock skew. Not adding.", ri->nickname);
routerinfo_free(ri);
*desc = end;
return 0;
}
if (ri->published_on < now-ROUTER_MAX_AGE) {
log_fn(LOG_WARN, "Publication time for router with nickname %s is too far in the past. Not adding.", ri->nickname);
routerinfo_free(ri);
*desc = end;
return 0;
}
/* Do we already have an entry for this router? */
for (i = 0; i < smartlist_len(descriptor_list); ++i) {
ent = smartlist_get(descriptor_list, i);
if (!strcasecmp(ri->nickname, ent->nickname)) {
found = i;
break;
}
}
if (found >= 0) {
/* if so, decide whether to update it. */
if (ent->published > ri->published_on) {
/* We already have a newer descriptor */
log_fn(LOG_INFO,"We already have a newer desc for nickname %s. Not adding.",ri->nickname);
/* This isn't really an error; return success. */
routerinfo_free(ri);
*desc = end;
return 1;
}
/* We don't have a newer one; we'll update this one. */
log_fn(LOG_INFO,"Dirserv updating desc for nickname %s",ri->nickname);
free_descriptor_entry(ent);
smartlist_del_keeporder(descriptor_list, found);
} else {
/* Add at the end. */
log_fn(LOG_INFO,"Dirserv adding desc for nickname %s",ri->nickname);
}
ent = tor_malloc(sizeof(descriptor_entry_t));
ent->nickname = tor_strdup(ri->nickname);
ent->published = ri->published_on;
ent->desc_len = desc_len;
ent->descriptor = tor_malloc(desc_len+1);
strncpy(ent->descriptor, start, desc_len);
ent->descriptor[desc_len] = '\0';
ent->router = ri;
smartlist_add(descriptor_list, ent);
*desc = end;
directory_set_dirty();
return 1;
}
/** Remove all descriptors whose nicknames or fingerprints we don't
* recognize. (Descriptors that used to be good can become
* unrecognized when we reload the fingerprint list.)
*/
static void
directory_remove_unrecognized(void)
{
int i;
descriptor_entry_t *ent;
if (!descriptor_list)
descriptor_list = smartlist_create();
for (i = 0; i < smartlist_len(descriptor_list); ++i) {
ent = smartlist_get(descriptor_list, i);
if (dirserv_router_fingerprint_is_known(ent->router)<=0) {
log(LOG_INFO, "Router %s is no longer recognized",
ent->nickname);
free_descriptor_entry(ent);
smartlist_del(descriptor_list, i--);
}
}
}
/** Mark the directory as dirty -- when we're next asked for a
* directory, we will rebuild it instead of reusing the most recently
* generated one.
*/
void
directory_set_dirty()
{
the_directory_is_dirty = 1;
}
/** Load all descriptors from an earlier directory stored in the string
* dir.
*/
int
dirserv_init_from_directory_string(const char *dir)
{
const char *cp = dir;
while(1) {
cp = strstr(cp, "\nrouter ");
if (!cp) break;
++cp;
if (dirserv_add_descriptor(&cp) < 0) {
return -1;
}
--cp; /*Back up to newline.*/
}
return 0;
}
/** Set *nicknames_out to a comma-separated list of all the ORs that we
* believe are currently running (because we have open connections to
* them). Return 0 on success; -1 on error.
*/
static int
list_running_servers(char **nicknames_out)
{
connection_t **connection_array;
int n_conns;
connection_t *conn;
char *cp;
int i;
int length;
smartlist_t *nicknames;
*nicknames_out = NULL;
nicknames = smartlist_create();
smartlist_add(nicknames, options.Nickname);
get_connection_array(&connection_array, &n_conns);
for (i = 0; itype != CONN_TYPE_OR || conn->state != OR_CONN_STATE_OPEN)
continue; /* only list successfully handshaked OR's. */
if(!conn->nickname) /* it's an OP, don't list it */
continue;
if (!router_nickname_is_approved(conn->nickname))
continue; /* If we removed them from the approved list, don't list it.*/
smartlist_add(nicknames, conn->nickname);
}
length = smartlist_len(nicknames) + 1; /* spaces + EOS + 1. */
SMARTLIST_FOREACH(nicknames, char *, c, length += strlen(c));
*nicknames_out = tor_malloc_zero(length);
cp = *nicknames_out;
for (i = 0; ipublished < cutoff) {
/* descriptor_list[i] is too old. Remove it. */
free_descriptor_entry(ent);
smartlist_del(descriptor_list, i--);
directory_set_dirty();
}
}
}
/** Dump all routers currently in the directory into the string
* s, using at most maxlen characters, and signing the
* directory with private_key. Return 0 on success, -1 on
* failure.
*/
int
dirserv_dump_directory_to_string(char *s, unsigned int maxlen,
crypto_pk_env_t *private_key)
{
char *cp, *eos;
char digest[20];
char signature[128];
char published[33];
time_t published_on;
int i;
eos = s+maxlen;
if (!descriptor_list)
descriptor_list = smartlist_create();
if (list_running_servers(&cp))
return -1;
dirserv_remove_old_servers();
published_on = time(NULL);
strftime(published, 32, "%Y-%m-%d %H:%M:%S", gmtime(&published_on));
snprintf(s, maxlen,
"signed-directory\n"
"published %s\n"
"recommended-software %s\n"
"running-routers %s\n\n", published, options.RecommendedVersions, cp);
free(cp);
i = strlen(s);
cp = s+i;
SMARTLIST_FOREACH(descriptor_list, descriptor_entry_t *, d,
if (strlcat(s, d->descriptor, maxlen) >= maxlen)
goto truncated);
/* These multiple strlcat calls are inefficient, but dwarfed by the RSA
signature.
*/
if (strlcat(s, "directory-signature ", maxlen) >= maxlen)
goto truncated;
if (strlcat(s, options.Nickname, maxlen) >= maxlen)
goto truncated;
if (strlcat(s, "\n", maxlen) >= maxlen)
goto truncated;
if (router_get_dir_hash(s,digest)) {
log_fn(LOG_WARN,"couldn't compute digest");
return -1;
}
if (crypto_pk_private_sign(private_key, digest, 20, signature) < 0) {
log_fn(LOG_WARN,"couldn't sign digest");
return -1;
}
log(LOG_DEBUG,"generated directory digest begins with %s",hex_str(digest,4));
if (strlcat(cp, "-----BEGIN SIGNATURE-----\n", maxlen) >= maxlen)
goto truncated;
i = strlen(s);
cp = s+i;
if (base64_encode(cp, maxlen-i, signature, 128) < 0) {
log_fn(LOG_WARN,"couldn't base64-encode signature");
return -1;
}
if (strlcat(s, "-----END SIGNATURE-----\n", maxlen) >= maxlen)
goto truncated;
return 0;
truncated:
log_fn(LOG_WARN,"tried to exceed string length.");
return -1;
}
/** Most recently generated encoded signed directory. */
static char *the_directory = NULL;
static int the_directory_len = -1;
/** Set *directory to the most recently generated encoded signed
* directory, generating a new one as necessary. */
size_t dirserv_get_directory(const char **directory)
{
char *new_directory;
char filename[512];
if (the_directory_is_dirty) {
new_directory = tor_malloc(MAX_DIR_SIZE);
if (dirserv_dump_directory_to_string(new_directory, MAX_DIR_SIZE,
get_identity_key())) {
log(LOG_WARN, "Error creating directory.");
free(new_directory);
return 0;
}
tor_free(the_directory);
the_directory = new_directory;
the_directory_len = strlen(the_directory);
log_fn(LOG_INFO,"New directory (size %d):\n%s",the_directory_len,
the_directory);
the_directory_is_dirty = 0;
/* Now read the directory we just made in order to update our own
* router lists. This does more signature checking than is strictly
* necessary, but safe is better than sorry. */
new_directory = tor_strdup(the_directory);
/* use a new copy of the dir, since get_dir_from_string scribbles on it */
if (router_load_routerlist_from_directory(new_directory, get_identity_key())) {
log_fn(LOG_ERR, "We just generated a directory we can't parse. Dying.");
exit(0);
}
free(new_directory);
sprintf(filename,"%s/cached-directory", options.DataDirectory);
if(write_str_to_file(filename,the_directory) < 0) {
log_fn(LOG_WARN, "Couldn't write cached directory to disk. Ignoring.");
}
} else {
log(LOG_INFO,"Directory still clean, reusing.");
}
*directory = the_directory;
return the_directory_len;
}
/** Set *rr to the most recently generated encoded signed
* running-routers list, generating a new one as necessary. */
size_t dirserv_get_runningrouters(const char **rr)
{
/* XXX008 fill in this function */
return 0;
}
/*
Local Variables:
mode:c
indent-tabs-mode:nil
c-basic-offset:2
End:
*/