[tor-commits] [tor/maint-0.2.7] Merge branch 'maint-0.2.6' into maint-0.2.7

nickm at torproject.org nickm at torproject.org
Tue Dec 20 23:16:34 UTC 2016


commit a9c8a5ff18c1944ddcea0116419edc2f199583b8
Merge: b49369b b18bde2
Author: Nick Mathewson <nickm at torproject.org>
Date:   Tue Dec 20 18:14:21 2016 -0500

    Merge branch 'maint-0.2.6' into maint-0.2.7

 changes/bug21018     | 11 +++++++++++
 src/or/rendcache.c   |  6 ++++--
 src/or/routerparse.c |  6 +++---
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --cc src/or/rendcache.c
index d4bdd68,0000000..e7b1ce9
mode 100644,000000..100644
--- a/src/or/rendcache.c
+++ b/src/or/rendcache.c
@@@ -1,898 -1,0 +1,900 @@@
 +/* Copyright (c) 2015, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file rendcache.c
 + * \brief Hidden service desriptor cache.
 + **/
 +
 +#include "rendcache.h"
 +
 +#include "config.h"
 +#include "rephist.h"
 +#include "routerlist.h"
 +#include "routerparse.h"
 +
 +/** Map from service id (as generated by rend_get_service_id) to
 + * rend_cache_entry_t. */
 +static strmap_t *rend_cache = NULL;
 +
 +/** Map from descriptor id to rend_cache_entry_t; only for hidden service
 + * directories. */
 +static digestmap_t *rend_cache_v2_dir = NULL;
 +
 +/** (Client side only) Map from service id to rend_cache_failure_t. This
 + * cache is used to track intro point(IP) failures so we know when to keep
 + * or discard a new descriptor we just fetched. Here is a description of the
 + * cache behavior.
 + *
 + * Everytime tor discards an IP (ex: receives a NACK), we add an entry to
 + * this cache noting the identity digest of the IP and it's failure type for
 + * the service ID. The reason we indexed this cache by service ID is to
 + * differentiate errors that can occur only for a specific service like a
 + * NACK for instance. It applies for one but maybe not for the others.
 + *
 + * Once a service descriptor is fetched and considered valid, each IP is
 + * looked up in this cache and if present, it is discarded from the fetched
 + * descriptor. At the end, all IP(s) in the cache, for a specific service
 + * ID, that were NOT present in the descriptor are removed from this cache.
 + * Which means that if at least one IP was not in this cache, thus usuable,
 + * it's considered a new descriptor so we keep it. Else, if all IPs were in
 + * this cache, we discard the descriptor as it's considered unsuable.
 + *
 + * Once a descriptor is removed from the rend cache or expires, the entry
 + * in this cache is also removed for the service ID.
 + *
 + * This scheme allows us to not realy on the descriptor's timestamp (which
 + * is rounded down to the hour) to know if we have a newer descriptor. We
 + * only rely on the usability of intro points from an internal state. */
 +static strmap_t *rend_cache_failure = NULL;
 +
 +/** DOCDOC */
 +static size_t rend_cache_total_allocation = 0;
 +
 +/** Initializes the service descriptor cache.
 +*/
 +void
 +rend_cache_init(void)
 +{
 +  rend_cache = strmap_new();
 +  rend_cache_v2_dir = digestmap_new();
 +  rend_cache_failure = strmap_new();
 +}
 +
 +/** Return the approximate number of bytes needed to hold <b>e</b>. */
 +static size_t
 +rend_cache_entry_allocation(const rend_cache_entry_t *e)
 +{
 +  if (!e)
 +    return 0;
 +
 +  /* This doesn't count intro_nodes or key size */
 +  return sizeof(*e) + e->len + sizeof(*e->parsed);
 +}
 +
 +/** DOCDOC */
 +size_t
 +rend_cache_get_total_allocation(void)
 +{
 +  return rend_cache_total_allocation;
 +}
 +
 +/** Decrement the total bytes attributed to the rendezvous cache by n. */
 +static void
 +rend_cache_decrement_allocation(size_t n)
 +{
 +  static int have_underflowed = 0;
 +
 +  if (rend_cache_total_allocation >= n) {
 +    rend_cache_total_allocation -= n;
 +  } else {
 +    rend_cache_total_allocation = 0;
 +    if (! have_underflowed) {
 +      have_underflowed = 1;
 +      log_warn(LD_BUG, "Underflow in rend_cache_decrement_allocation");
 +    }
 +  }
 +}
 +
 +/** Increase the total bytes attributed to the rendezvous cache by n. */
 +static void
 +rend_cache_increment_allocation(size_t n)
 +{
 +  static int have_overflowed = 0;
 +  if (rend_cache_total_allocation <= SIZE_MAX - n) {
 +    rend_cache_total_allocation += n;
 +  } else {
 +    rend_cache_total_allocation = SIZE_MAX;
 +    if (! have_overflowed) {
 +      have_overflowed = 1;
 +      log_warn(LD_BUG, "Overflow in rend_cache_increment_allocation");
 +    }
 +  }
 +}
 +
 +/** Helper: free a rend cache failure intro object. */
 +static void
 +rend_cache_failure_intro_entry_free(rend_cache_failure_intro_t *entry)
 +{
 +  if (entry == NULL) {
 +    return;
 +  }
 +  tor_free(entry);
 +}
 +
 +static void
 +rend_cache_failure_intro_entry_free_(void *entry)
 +{
 +  rend_cache_failure_intro_entry_free(entry);
 +}
 +
 +/** Allocate a rend cache failure intro object and return it. <b>failure</b>
 + * is set into the object. This function can not fail. */
 +static rend_cache_failure_intro_t *
 +rend_cache_failure_intro_entry_new(rend_intro_point_failure_t failure)
 +{
 +  rend_cache_failure_intro_t *entry = tor_malloc(sizeof(*entry));
 +  entry->failure_type = failure;
 +  entry->created_ts = time(NULL);
 +  return entry;
 +}
 +
 +/** Helper: free a rend cache failure object. */
 +static void
 +rend_cache_failure_entry_free(rend_cache_failure_t *entry)
 +{
 +  if (entry == NULL) {
 +    return;
 +  }
 +
 +  /* Free and remove every intro failure object. */
 +  digestmap_free(entry->intro_failures,
 +                 rend_cache_failure_intro_entry_free_);
 +
 +  tor_free(entry);
 +}
 +
 +/** Helper: deallocate a rend_cache_failure_t. (Used with strmap_free(),
 + * which requires a function pointer whose argument is void*). */
 +static void
 +rend_cache_failure_entry_free_(void *entry)
 +{
 +  rend_cache_failure_entry_free(entry);
 +}
 +
 +/** Allocate a rend cache failure object and return it. This function can
 + * not fail. */
 +static rend_cache_failure_t *
 +rend_cache_failure_entry_new(void)
 +{
 +  rend_cache_failure_t *entry = tor_malloc(sizeof(*entry));
 +  entry->intro_failures = digestmap_new();
 +  return entry;
 +}
 +
 +/** Remove failure cache entry for the service ID in the given descriptor
 + * <b>desc</b>. */
 +static void
 +rend_cache_failure_remove(rend_service_descriptor_t *desc)
 +{
 +  char service_id[REND_SERVICE_ID_LEN_BASE32 + 1];
 +  rend_cache_failure_t *entry;
 +
 +  if (desc == NULL) {
 +    return;
 +  }
 +  if (rend_get_service_id(desc->pk, service_id) < 0) {
 +    return;
 +  }
 +  entry = strmap_get_lc(rend_cache_failure, service_id);
 +  if (entry != NULL) {
 +    strmap_remove_lc(rend_cache_failure, service_id);
 +    rend_cache_failure_entry_free(entry);
 +  }
 +}
 +
 +/** Helper: free storage held by a single service descriptor cache entry. */
 +static void
 +rend_cache_entry_free(rend_cache_entry_t *e)
 +{
 +  if (!e)
 +    return;
 +  rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
 +  /* We are about to remove a descriptor from the cache so remove the entry
 +   * in the failure cache. */
 +  rend_cache_failure_remove(e->parsed);
 +  rend_service_descriptor_free(e->parsed);
 +  tor_free(e->desc);
 +  tor_free(e);
 +}
 +
 +/** Helper: deallocate a rend_cache_entry_t.  (Used with strmap_free(), which
 + * requires a function pointer whose argument is void*). */
 +static void
 +rend_cache_entry_free_(void *p)
 +{
 +  rend_cache_entry_free(p);
 +}
 +
 +/** Free all storage held by the service descriptor cache. */
 +void
 +rend_cache_free_all(void)
 +{
 +  strmap_free(rend_cache, rend_cache_entry_free_);
 +  digestmap_free(rend_cache_v2_dir, rend_cache_entry_free_);
 +  strmap_free(rend_cache_failure, rend_cache_failure_entry_free_);
 +  rend_cache = NULL;
 +  rend_cache_v2_dir = NULL;
 +  rend_cache_failure = NULL;
 +  rend_cache_total_allocation = 0;
 +}
 +
 +/** Remove all entries that re REND_CACHE_FAILURE_MAX_AGE old. This is
 + * called every second.
 + *
 + * We have to clean these regurlarly else if for whatever reasons an hidden
 + * service goes offline and a client tries to connect to it during that
 + * time, a failure entry is created and the client will be unable to connect
 + * for a while even though the service has return online.  */
 +void
 +rend_cache_failure_clean(time_t now)
 +{
 +  time_t cutoff = now - REND_CACHE_FAILURE_MAX_AGE;
 +  STRMAP_FOREACH_MODIFY(rend_cache_failure, key,
 +                        rend_cache_failure_t *, ent) {
 +    /* Free and remove every intro failure object that match the cutoff. */
 +    DIGESTMAP_FOREACH_MODIFY(ent->intro_failures, ip_key,
 +                             rend_cache_failure_intro_t *, ip_ent) {
 +      if (ip_ent->created_ts < cutoff) {
 +        rend_cache_failure_intro_entry_free(ip_ent);
 +        MAP_DEL_CURRENT(ip_key);
 +      }
 +    } DIGESTMAP_FOREACH_END;
 +    /* If the entry is now empty of intro point failures, remove it. */
 +    if (digestmap_isempty(ent->intro_failures)) {
 +      rend_cache_failure_entry_free(ent);
 +      MAP_DEL_CURRENT(key);
 +    }
 +  } STRMAP_FOREACH_END;
 +}
 +
 +/** Removes all old entries from the service descriptor cache.
 +*/
 +void
 +rend_cache_clean(time_t now)
 +{
 +  strmap_iter_t *iter;
 +  const char *key;
 +  void *val;
 +  rend_cache_entry_t *ent;
 +  time_t cutoff = now - REND_CACHE_MAX_AGE - REND_CACHE_MAX_SKEW;
 +  for (iter = strmap_iter_init(rend_cache); !strmap_iter_done(iter); ) {
 +    strmap_iter_get(iter, &key, &val);
 +    ent = (rend_cache_entry_t*)val;
 +    if (ent->parsed->timestamp < cutoff) {
 +      iter = strmap_iter_next_rmv(rend_cache, iter);
 +      rend_cache_entry_free(ent);
 +    } else {
 +      iter = strmap_iter_next(rend_cache, iter);
 +    }
 +  }
 +}
 +
 +/** Remove ALL entries from the rendezvous service descriptor cache.
 +*/
 +void
 +rend_cache_purge(void)
 +{
 +  if (rend_cache) {
 +    log_info(LD_REND, "Purging HS descriptor cache");
 +    strmap_free(rend_cache, rend_cache_entry_free_);
 +  }
 +  rend_cache = strmap_new();
 +}
 +
 +/** Remove ALL entries from the failure cache. This is also called when a
 + * NEWNYM signal is received. */
 +void
 +rend_cache_failure_purge(void)
 +{
 +  if (rend_cache_failure) {
 +    log_info(LD_REND, "Purging HS failure cache");
 +    strmap_free(rend_cache_failure, rend_cache_failure_entry_free_);
 +  }
 +  rend_cache_failure = strmap_new();
 +}
 +
 +/** Lookup the rend failure cache using a relay identity digest in
 + * <b>identity</b> and service ID <b>service_id</b>. If found, the intro
 + * failure is set in <b>intro_entry</b> else it stays untouched. Return 1
 + * iff found else 0. */
 +static int
 +cache_failure_intro_lookup(const uint8_t *identity, const char *service_id,
 +                           rend_cache_failure_intro_t **intro_entry)
 +{
 +  rend_cache_failure_t *elem;
 +  rend_cache_failure_intro_t *intro_elem;
 +
 +  tor_assert(rend_cache_failure);
 +
 +  if (intro_entry) {
 +    *intro_entry = NULL;
 +  }
 +
 +  /* Lookup descriptor and return it. */
 +  elem = strmap_get_lc(rend_cache_failure, service_id);
 +  if (elem == NULL) {
 +    goto not_found;
 +  }
 +  intro_elem = digestmap_get(elem->intro_failures, (char *) identity);
 +  if (intro_elem == NULL) {
 +    goto not_found;
 +  }
 +  if (intro_entry) {
 +    *intro_entry = intro_elem;
 +  }
 +  return 1;
 + not_found:
 +  return 0;
 +}
 +
 +/** Allocate a new cache failure intro object and copy the content from
 + * <b>entry</b> to this newly allocated object. Return it. */
 +static rend_cache_failure_intro_t *
 +cache_failure_intro_dup(const rend_cache_failure_intro_t *entry)
 +{
 +  rend_cache_failure_intro_t *ent_dup =
 +    rend_cache_failure_intro_entry_new(entry->failure_type);
 +  ent_dup->created_ts = entry->created_ts;
 +  return ent_dup;
 +}
 +
 +/** Add an intro point failure to the failure cache using the relay
 + * <b>identity</b> and service ID <b>service_id</b>. Record the
 + * <b>failure</b> in that object. */
 +static void
 +cache_failure_intro_add(const uint8_t *identity, const char *service_id,
 +                        rend_intro_point_failure_t failure)
 +{
 +  rend_cache_failure_t *fail_entry;
 +  rend_cache_failure_intro_t *entry, *old_entry;
 +
 +  /* Make sure we have a failure object for this service ID and if not,
 +   * create it with this new intro failure entry. */
 +  fail_entry = strmap_get_lc(rend_cache_failure, service_id);
 +  if (fail_entry == NULL) {
 +    fail_entry = rend_cache_failure_entry_new();
 +    /* Add failure entry to global rend failure cache. */
 +    strmap_set_lc(rend_cache_failure, service_id, fail_entry);
 +  }
 +  entry = rend_cache_failure_intro_entry_new(failure);
 +  old_entry = digestmap_set(fail_entry->intro_failures,
 +                            (char *) identity, entry);
 +  /* This _should_ be NULL, but in case it isn't, free it. */
 +  rend_cache_failure_intro_entry_free(old_entry);
 +}
 +
 +/** Using a parsed descriptor <b>desc</b>, check if the introduction points
 + * are present in the failure cache and if so they are removed from the
 + * descriptor and kept into the failure cache. Then, each intro points that
 + * are NOT in the descriptor but in the failure cache for the given
 + * <b>service_id</b> are removed from the failure cache. */
 +static void
 +validate_intro_point_failure(const rend_service_descriptor_t *desc,
 +                             const char *service_id)
 +{
 +  rend_cache_failure_t *new_entry, *cur_entry;
 +  /* New entry for the service ID that will be replacing the one in the
 +   * failure cache since we have a new descriptor. In the case where all
 +   * intro points are removed, we are assured that the new entry is the same
 +   * as the current one. */
 +  new_entry = tor_malloc(sizeof(*new_entry));
 +  new_entry->intro_failures = digestmap_new();
 +
 +  tor_assert(desc);
 +
 +  SMARTLIST_FOREACH_BEGIN(desc->intro_nodes, rend_intro_point_t *, intro) {
 +    int found;
 +    rend_cache_failure_intro_t *entry;
 +    const uint8_t *identity =
 +      (uint8_t *) intro->extend_info->identity_digest;
 +
 +    found = cache_failure_intro_lookup(identity, service_id, &entry);
 +    if (found) {
 +      /* Dup here since it will be freed at the end when removing the
 +       * original entry in the cache. */
 +      rend_cache_failure_intro_t *ent_dup = cache_failure_intro_dup(entry);
 +      /* This intro point is in our cache, discard it from the descriptor
 +       * because chances are that it's unusable. */
 +      SMARTLIST_DEL_CURRENT(desc->intro_nodes, intro);
 +      /* Keep it for our new entry. */
 +      digestmap_set(new_entry->intro_failures, (char *) identity, ent_dup);
 +      /* Only free it when we're done looking at it. */
 +      rend_intro_point_free(intro);
 +      continue;
 +    }
 +  } SMARTLIST_FOREACH_END(intro);
 +
 +  /* Swap the failure entry in the cache and free the current one. */
 +  cur_entry = strmap_get_lc(rend_cache_failure, service_id);
 +  if (cur_entry != NULL) {
 +    rend_cache_failure_entry_free(cur_entry);
 +  }
 +  strmap_set_lc(rend_cache_failure, service_id, new_entry);
 +}
 +
 +/** Note down an intro failure in the rend failure cache using the type of
 + * failure in <b>failure</b> for the relay identity digest in
 + * <b>identity</b> and service ID <b>service_id</b>. If an entry already
 + * exists in the cache, the failure type is changed with <b>failure</b>. */
 +void
 +rend_cache_intro_failure_note(rend_intro_point_failure_t failure,
 +                              const uint8_t *identity,
 +                              const char *service_id)
 +{
 +  int found;
 +  rend_cache_failure_intro_t *entry;
 +
 +  found = cache_failure_intro_lookup(identity, service_id, &entry);
 +  if (!found) {
 +    cache_failure_intro_add(identity, service_id, failure);
 +  } else {
 +    /* Replace introduction point failure with this one. */
 +    entry->failure_type = failure;
 +  }
 +}
 +
 +/** Remove all old v2 descriptors and those for which this hidden service
 + * directory is not responsible for any more.
 + *
 + * If at all possible, remove at least <b>force_remove</b> bytes of data.
 + */
 +void
 +rend_cache_clean_v2_descs_as_dir(time_t now, size_t force_remove)
 +{
 +  digestmap_iter_t *iter;
 +  time_t cutoff = now - REND_CACHE_MAX_AGE - REND_CACHE_MAX_SKEW;
 +  const int LAST_SERVED_CUTOFF_STEP = 1800;
 +  time_t last_served_cutoff = cutoff;
 +  size_t bytes_removed = 0;
 +  do {
 +    for (iter = digestmap_iter_init(rend_cache_v2_dir);
 +         !digestmap_iter_done(iter); ) {
 +      const char *key;
 +      void *val;
 +      rend_cache_entry_t *ent;
 +      digestmap_iter_get(iter, &key, &val);
 +      ent = val;
 +      if (ent->parsed->timestamp < cutoff ||
 +          ent->last_served < last_served_cutoff ||
 +          !hid_serv_responsible_for_desc_id(key)) {
 +        char key_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
 +        base32_encode(key_base32, sizeof(key_base32), key, DIGEST_LEN);
 +        log_info(LD_REND, "Removing descriptor with ID '%s' from cache",
 +                 safe_str_client(key_base32));
 +        bytes_removed += rend_cache_entry_allocation(ent);
 +        iter = digestmap_iter_next_rmv(rend_cache_v2_dir, iter);
 +        rend_cache_entry_free(ent);
 +      } else {
 +        iter = digestmap_iter_next(rend_cache_v2_dir, iter);
 +      }
 +    }
 +
 +    /* In case we didn't remove enough bytes, advance the cutoff a little. */
 +    last_served_cutoff += LAST_SERVED_CUTOFF_STEP;
 +    if (last_served_cutoff > now)
 +      break;
 +  } while (bytes_removed < force_remove);
 +}
 +
 +/** Lookup in the client cache the given service ID <b>query</b> for
 + * <b>version</b>.
 + *
 + * Return 0 if found and if <b>e</b> is non NULL, set it with the entry
 + * found. Else, a negative value is returned and <b>e</b> is untouched.
 + * -EINVAL means that <b>query</b> is not a valid service id.
 + * -ENOENT means that no entry in the cache was found. */
 +int
 +rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e)
 +{
 +  int ret = 0;
 +  char key[REND_SERVICE_ID_LEN_BASE32 + 2]; /* <version><query>\0 */
 +  rend_cache_entry_t *entry = NULL;
 +  static const int default_version = 2;
 +
 +  tor_assert(rend_cache);
 +  tor_assert(query);
 +
 +  if (!rend_valid_service_id(query)) {
 +    ret = -EINVAL;
 +    goto end;
 +  }
 +
 +  switch (version) {
 +    case 0:
 +      log_warn(LD_REND, "Cache lookup of a v0 renddesc is deprecated.");
 +      break;
 +    case 2:
 +      /* Default is version 2. */
 +    default:
 +      tor_snprintf(key, sizeof(key), "%d%s", default_version, query);
 +      entry = strmap_get_lc(rend_cache, key);
 +      break;
 +  }
 +  if (!entry) {
 +    ret = -ENOENT;
 +    goto end;
 +  }
 +  tor_assert(entry->parsed && entry->parsed->intro_nodes);
 +
 +  if (e) {
 +    *e = entry;
 +  }
 +
 + end:
 +  return ret;
 +}
 +
 +/** Lookup the v2 service descriptor with base32-encoded <b>desc_id</b> and
 + * copy the pointer to it to *<b>desc</b>.  Return 1 on success, 0 on
 + * well-formed-but-not-found, and -1 on failure.
 + */
 +int
 +rend_cache_lookup_v2_desc_as_dir(const char *desc_id, const char **desc)
 +{
 +  rend_cache_entry_t *e;
 +  char desc_id_digest[DIGEST_LEN];
 +  tor_assert(rend_cache_v2_dir);
 +  if (base32_decode(desc_id_digest, DIGEST_LEN,
 +                    desc_id, REND_DESC_ID_V2_LEN_BASE32) < 0) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_REND,
 +           "Rejecting v2 rendezvous descriptor request -- descriptor ID "
 +           "contains illegal characters: %s",
 +           safe_str(desc_id));
 +    return -1;
 +  }
 +  /* Lookup descriptor and return. */
 +  e = digestmap_get(rend_cache_v2_dir, desc_id_digest);
 +  if (e) {
 +    *desc = e->desc;
 +    e->last_served = approx_time();
 +    return 1;
 +  }
 +  return 0;
 +}
 +
 +/** Parse the v2 service descriptor(s) in <b>desc</b> and store it/them to the
 + * local rend cache. Don't attempt to decrypt the included list of introduction
 + * points (as we don't have a descriptor cookie for it).
 + *
 + * If we have a newer descriptor with the same ID, ignore this one.
 + * If we have an older descriptor with the same ID, replace it.
 + *
 + * Return an appropriate rend_cache_store_status_t.
 + */
 +rend_cache_store_status_t
 +rend_cache_store_v2_desc_as_dir(const char *desc)
 +{
 +  const or_options_t *options = get_options();
 +  rend_service_descriptor_t *parsed;
 +  char desc_id[DIGEST_LEN];
 +  char *intro_content;
 +  size_t intro_size;
 +  size_t encoded_size;
 +  char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
 +  int number_parsed = 0, number_stored = 0;
 +  const char *current_desc = desc;
 +  const char *next_desc;
 +  rend_cache_entry_t *e;
 +  time_t now = time(NULL);
 +  tor_assert(rend_cache_v2_dir);
 +  tor_assert(desc);
 +  if (!hid_serv_acting_as_directory()) {
 +    /* Cannot store descs, because we are (currently) not acting as
 +     * hidden service directory. */
 +    log_info(LD_REND, "Cannot store descs: Not acting as hs dir");
 +    return RCS_NOTDIR;
 +  }
 +  while (rend_parse_v2_service_descriptor(&parsed, desc_id, &intro_content,
 +                                          &intro_size, &encoded_size,
 +                                          &next_desc, current_desc, 1) >= 0) {
 +    number_parsed++;
 +    /* We don't care about the introduction points. */
 +    tor_free(intro_content);
 +    /* For pretty log statements. */
 +    base32_encode(desc_id_base32, sizeof(desc_id_base32),
 +                  desc_id, DIGEST_LEN);
 +    /* Is desc ID in the range that we are (directly or indirectly) responsible
 +     * for? */
 +    if (!hid_serv_responsible_for_desc_id(desc_id)) {
 +      log_info(LD_REND, "Service descriptor with desc ID %s is not in "
 +               "interval that we are responsible for.",
 +               safe_str_client(desc_id_base32));
 +      goto skip;
 +    }
 +    /* Is descriptor too old? */
 +    if (parsed->timestamp < now - REND_CACHE_MAX_AGE-REND_CACHE_MAX_SKEW) {
 +      log_info(LD_REND, "Service descriptor with desc ID %s is too old.",
 +               safe_str(desc_id_base32));
 +      goto skip;
 +    }
 +    /* Is descriptor too far in the future? */
 +    if (parsed->timestamp > now + REND_CACHE_MAX_SKEW) {
 +      log_info(LD_REND, "Service descriptor with desc ID %s is too far in the "
 +               "future.",
 +               safe_str(desc_id_base32));
 +      goto skip;
 +    }
 +    /* Do we already have a newer descriptor? */
 +    e = digestmap_get(rend_cache_v2_dir, desc_id);
 +    if (e && e->parsed->timestamp > parsed->timestamp) {
 +      log_info(LD_REND, "We already have a newer service descriptor with the "
 +               "same desc ID %s and version.",
 +               safe_str(desc_id_base32));
 +      goto skip;
 +    }
 +    /* Do we already have this descriptor? */
 +    if (e && !strcmp(desc, e->desc)) {
 +      log_info(LD_REND, "We already have this service descriptor with desc "
 +               "ID %s.", safe_str(desc_id_base32));
 +      goto skip;
 +    }
 +    /* Store received descriptor. */
 +    if (!e) {
 +      e = tor_malloc_zero(sizeof(rend_cache_entry_t));
 +      digestmap_set(rend_cache_v2_dir, desc_id, e);
 +      /* Treat something just uploaded as having been served a little
 +       * while ago, so that flooding with new descriptors doesn't help
 +       * too much.
 +       */
 +      e->last_served = approx_time() - 3600;
 +    } else {
 +      rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
 +      rend_service_descriptor_free(e->parsed);
 +      tor_free(e->desc);
 +    }
 +    e->parsed = parsed;
 +    e->desc = tor_strndup(current_desc, encoded_size);
 +    e->len = encoded_size;
 +    rend_cache_increment_allocation(rend_cache_entry_allocation(e));
 +    log_info(LD_REND, "Successfully stored service descriptor with desc ID "
 +             "'%s' and len %d.",
 +             safe_str(desc_id_base32), (int)encoded_size);
 +
 +    /* Statistics: Note down this potentially new HS. */
 +    if (options->HiddenServiceStatistics) {
 +      rep_hist_stored_maybe_new_hs(e->parsed->pk);
 +    }
 +
 +    number_stored++;
 +    goto advance;
 + skip:
 +    rend_service_descriptor_free(parsed);
 + advance:
 +    /* advance to next descriptor, if available. */
 +    current_desc = next_desc;
 +    /* check if there is a next descriptor. */
 +    if (!current_desc ||
 +        strcmpstart(current_desc, "rendezvous-service-descriptor "))
 +      break;
 +  }
 +  if (!number_parsed) {
 +    log_info(LD_REND, "Could not parse any descriptor.");
 +    return RCS_BADDESC;
 +  }
 +  log_info(LD_REND, "Parsed %d and added %d descriptor%s.",
 +           number_parsed, number_stored, number_stored != 1 ? "s" : "");
 +  return RCS_OKAY;
 +}
 +
 +/** Parse the v2 service descriptor in <b>desc</b>, decrypt the included list
 + * of introduction points with <b>descriptor_cookie</b> (which may also be
 + * <b>NULL</b> if decryption is not necessary), and store the descriptor to
 + * the local cache under its version and service id.
 + *
 + * If we have a newer v2 descriptor with the same ID, ignore this one.
 + * If we have an older descriptor with the same ID, replace it.
 + * If the descriptor's service ID does not match
 + * <b>rend_query</b>-\>onion_address, reject it.
 + *
 + * If the descriptor's descriptor ID doesn't match <b>desc_id_base32</b>,
 + * reject it.
 + *
 + * Return an appropriate rend_cache_store_status_t. If entry is not NULL,
 + * set it with the cache entry pointer of the descriptor.
 + */
 +rend_cache_store_status_t
 +rend_cache_store_v2_desc_as_client(const char *desc,
 +                                   const char *desc_id_base32,
 +                                   const rend_data_t *rend_query,
 +                                   rend_cache_entry_t **entry)
 +{
 +  /*XXXX this seems to have a bit of duplicate code with
 +   * rend_cache_store_v2_desc_as_dir().  Fix that. */
 +  /* Though having similar elements, both functions were separated on
 +   * purpose:
 +   * - dirs don't care about encoded/encrypted introduction points, clients
 +   *   do.
 +   * - dirs store descriptors in a separate cache by descriptor ID, whereas
 +   *   clients store them by service ID; both caches are different data
 +   *   structures and have different access methods.
 +   * - dirs store a descriptor only if they are responsible for its ID,
 +   *   clients do so in every way (because they have requested it before).
 +   * - dirs can process multiple concatenated descriptors which is required
 +   *   for replication, whereas clients only accept a single descriptor.
 +   * Thus, combining both methods would result in a lot of if statements
 +   * which probably would not improve, but worsen code readability. -KL */
 +  rend_service_descriptor_t *parsed = NULL;
 +  char desc_id[DIGEST_LEN];
 +  char *intro_content = NULL;
 +  size_t intro_size;
 +  size_t encoded_size;
 +  const char *next_desc;
 +  time_t now = time(NULL);
 +  char key[REND_SERVICE_ID_LEN_BASE32+2];
 +  char service_id[REND_SERVICE_ID_LEN_BASE32+1];
 +  char want_desc_id[DIGEST_LEN];
 +  rend_cache_entry_t *e;
 +  rend_cache_store_status_t retval = RCS_BADDESC;
 +  tor_assert(rend_cache);
 +  tor_assert(desc);
 +  tor_assert(desc_id_base32);
 +  memset(want_desc_id, 0, sizeof(want_desc_id));
 +  if (entry) {
 +    *entry = NULL;
 +  }
 +  if (base32_decode(want_desc_id, sizeof(want_desc_id),
 +                    desc_id_base32, strlen(desc_id_base32)) != 0) {
 +    log_warn(LD_BUG, "Couldn't decode base32 %s for descriptor id.",
 +             escaped_safe_str_client(desc_id_base32));
 +    goto err;
 +  }
 +  /* Parse the descriptor. */
 +  if (rend_parse_v2_service_descriptor(&parsed, desc_id, &intro_content,
 +                                       &intro_size, &encoded_size,
 +                                       &next_desc, desc, 0) < 0) {
 +    log_warn(LD_REND, "Could not parse descriptor.");
 +    goto err;
 +  }
 +  /* Compute service ID from public key. */
 +  if (rend_get_service_id(parsed->pk, service_id)<0) {
 +    log_warn(LD_REND, "Couldn't compute service ID.");
 +    goto err;
 +  }
 +  if (rend_query->onion_address[0] != '\0' &&
 +      strcmp(rend_query->onion_address, service_id)) {
 +    log_warn(LD_REND, "Received service descriptor for service ID %s; "
 +             "expected descriptor for service ID %s.",
 +             service_id, safe_str(rend_query->onion_address));
 +    goto err;
 +  }
 +  if (tor_memneq(desc_id, want_desc_id, DIGEST_LEN)) {
 +    log_warn(LD_REND, "Received service descriptor for %s with incorrect "
 +             "descriptor ID.", service_id);
 +    goto err;
 +  }
 +
 +  /* Decode/decrypt introduction points. */
 +  if (intro_content && intro_size > 0) {
 +    int n_intro_points;
 +    if (rend_query->auth_type != REND_NO_AUTH &&
 +        !tor_mem_is_zero(rend_query->descriptor_cookie,
 +                         sizeof(rend_query->descriptor_cookie))) {
 +      char *ipos_decrypted = NULL;
 +      size_t ipos_decrypted_size;
 +      if (rend_decrypt_introduction_points(&ipos_decrypted,
 +                                           &ipos_decrypted_size,
 +                                           rend_query->descriptor_cookie,
 +                                           intro_content,
 +                                           intro_size) < 0) {
 +        log_warn(LD_REND, "Failed to decrypt introduction points. We are "
 +                 "probably unable to parse the encoded introduction points.");
 +      } else {
 +        /* Replace encrypted with decrypted introduction points. */
 +        log_info(LD_REND, "Successfully decrypted introduction points.");
 +        tor_free(intro_content);
 +        intro_content = ipos_decrypted;
 +        intro_size = ipos_decrypted_size;
 +      }
 +    }
 +    n_intro_points = rend_parse_introduction_points(parsed, intro_content,
 +                                                    intro_size);
 +    if (n_intro_points <= 0) {
 +      log_warn(LD_REND, "Failed to parse introduction points. Either the "
-                "service has published a corrupt descriptor or you have "
-                "provided invalid authorization data.");
++               "service has published a corrupt descriptor, or you have "
++               "provided invalid authorization data, or (maybe!) the "
++               "server is deliberately serving broken data in an attempt "
++               "to crash you with bug 21018.");
 +      goto err;
 +    } else if (n_intro_points > MAX_INTRO_POINTS) {
 +      log_warn(LD_REND, "Found too many introduction points on a hidden "
 +               "service descriptor for %s. This is probably a (misguided) "
 +               "attempt to improve reliability, but it could also be an "
 +               "attempt to do a guard enumeration attack. Rejecting.",
 +               safe_str_client(service_id));
 +
 +      goto err;
 +    }
 +  } else {
 +    log_info(LD_REND, "Descriptor does not contain any introduction points.");
 +    parsed->intro_nodes = smartlist_new();
 +  }
 +  /* We don't need the encoded/encrypted introduction points any longer. */
 +  tor_free(intro_content);
 +  /* Is descriptor too old? */
 +  if (parsed->timestamp < now - REND_CACHE_MAX_AGE-REND_CACHE_MAX_SKEW) {
 +    log_warn(LD_REND, "Service descriptor with service ID %s is too old.",
 +             safe_str_client(service_id));
 +    goto err;
 +  }
 +  /* Is descriptor too far in the future? */
 +  if (parsed->timestamp > now + REND_CACHE_MAX_SKEW) {
 +    log_warn(LD_REND, "Service descriptor with service ID %s is too far in "
 +             "the future.", safe_str_client(service_id));
 +    goto err;
 +  }
 +  /* Do we have the same exact copy already in our cache? */
 +  tor_snprintf(key, sizeof(key), "2%s", service_id);
 +  e = (rend_cache_entry_t*) strmap_get_lc(rend_cache, key);
 +  if (e && !strcmp(desc, e->desc)) {
 +    log_info(LD_REND,"We already have this service descriptor %s.",
 +             safe_str_client(service_id));
 +    goto okay;
 +  }
 +  /* Verify that we are not replacing an older descriptor. It's important to
 +   * avoid an evil HSDir serving old descriptor. We validate if the
 +   * timestamp is greater than and not equal because it's a rounded down
 +   * timestamp to the hour so if the descriptor changed in the same hour,
 +   * the rend cache failure will tells us if we have a new descriptor. */
 +  if (e && e->parsed->timestamp > parsed->timestamp) {
 +    log_info(LD_REND, "We already have a new enough service descriptor for "
 +             "service ID %s with the same desc ID and version.",
 +             safe_str_client(service_id));
 +    goto okay;
 +  }
 +  /* Lookup our failure cache for intro point that might be unsuable. */
 +  validate_intro_point_failure(parsed, service_id);
 +  /* It's now possible that our intro point list is empty, this means that
 +   * this descriptor is useless to us because intro points have all failed
 +   * somehow before. Discard the descriptor. */
 +  if (smartlist_len(parsed->intro_nodes) == 0) {
 +    log_info(LD_REND, "Service descriptor with service ID %s, every "
 +             "intro points are unusable. Discarding it.",
 +             safe_str_client(service_id));
 +    goto err;
 +  }
 +  /* Now either purge the current one and replace it's content or create a
 +   * new one and add it to the rend cache. */
 +  if (!e) {
 +    e = tor_malloc_zero(sizeof(rend_cache_entry_t));
 +    strmap_set_lc(rend_cache, key, e);
 +  } else {
 +    rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
 +    rend_cache_failure_remove(e->parsed);
 +    rend_service_descriptor_free(e->parsed);
 +    tor_free(e->desc);
 +  }
 +  e->parsed = parsed;
 +  e->desc = tor_malloc_zero(encoded_size + 1);
 +  strlcpy(e->desc, desc, encoded_size + 1);
 +  e->len = encoded_size;
 +  rend_cache_increment_allocation(rend_cache_entry_allocation(e));
 +  log_debug(LD_REND,"Successfully stored rend desc '%s', len %d.",
 +            safe_str_client(service_id), (int)encoded_size);
 +  if (entry) {
 +    *entry = e;
 +  }
 +  return RCS_OKAY;
 +
 + okay:
 +  if (entry) {
 +    *entry = e;
 +  }
 +  retval = RCS_OKAY;
 +
 + err:
 +  rend_service_descriptor_free(parsed);
 +  tor_free(intro_content);
 +  return retval;
 +}
 +



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