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Merge remote-tracking branch 'dgoulet/rendcache_027_01'

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This commit is contained in:
Nick Mathewson 2015-06-19 09:10:03 -04:00
commit 8b35d85088
8 changed files with 640 additions and 613 deletions
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2
src/or/include.am
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@ -66,6 +66,7 @@ LIBTOR_A_SOURCES = \
src/or/policies.c \ src/or/policies.c \
src/or/reasons.c \ src/or/reasons.c \
src/or/relay.c \ src/or/relay.c \
src/or/rendcache.c \
src/or/rendclient.c \ src/or/rendclient.c \
src/or/rendcommon.c \ src/or/rendcommon.c \
src/or/rendmid.c \ src/or/rendmid.c \
@ -174,6 +175,7 @@ ORHEADERS = \
src/or/policies.h \ src/or/policies.h \
src/or/reasons.h \ src/or/reasons.h \
src/or/relay.h \ src/or/relay.h \
src/or/rendcache.h \
src/or/rendclient.h \ src/or/rendclient.h \
src/or/rendcommon.h \ src/or/rendcommon.h \
src/or/rendmid.h \ src/or/rendmid.h \

9
src/or/or.h
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@ -4970,15 +4970,6 @@ typedef struct rend_service_descriptor_t {
smartlist_t *successful_uploads; smartlist_t *successful_uploads;
} rend_service_descriptor_t; } rend_service_descriptor_t;
/** A cached rendezvous descriptor. */
typedef struct rend_cache_entry_t {
size_t len; /**< Length of <b>desc</b> */
time_t last_served; /**< When did we last write this one to somebody?
* (HSDir only) */
char *desc; /**< Service descriptor */
rend_service_descriptor_t *parsed; /**< Parsed value of 'desc' */
} rend_cache_entry_t;
/********************************* routerlist.c ***************************/ /********************************* routerlist.c ***************************/
/** Represents information about a single trusted or fallback directory /** Represents information about a single trusted or fallback directory

1
src/or/relay.c
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@ -32,6 +32,7 @@
#include "policies.h" #include "policies.h"
#include "reasons.h" #include "reasons.h"
#include "relay.h" #include "relay.h"
#include "rendcache.h"
#include "rendcommon.h" #include "rendcommon.h"
#include "router.h" #include "router.h"
#include "routerlist.h" #include "routerlist.h"

579
src/or/rendcache.c Normal file
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@ -0,0 +1,579 @@
/* 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 "rendcommon.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;
/** 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();
}
/** 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 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));
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_);
rend_cache = NULL;
rend_cache_v2_dir = NULL;
rend_cache_total_allocation = 0;
}
/** 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 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.");
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 already have a newer descriptor? */
tor_snprintf(key, sizeof(key), "2%s", service_id);
e = (rend_cache_entry_t*) strmap_get_lc(rend_cache, key);
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;
}
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_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;
}

56
src/or/rendcache.h Normal file
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@ -0,0 +1,56 @@
/* Copyright (c) 2015, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file rendcache.h
* \brief Header file for rendcache.c
**/
#ifndef TOR_RENDCACHE_H
#define TOR_RENDCACHE_H
#include "or.h"
/** How old do we let hidden service descriptors get before discarding
* them as too old? */
#define REND_CACHE_MAX_AGE (2*24*60*60)
/** How wrong do we assume our clock may be when checking whether hidden
* services are too old or too new? */
#define REND_CACHE_MAX_SKEW (24*60*60)
/* Do not allow more than this many introduction points in a hidden service
* descriptor */
#define MAX_INTRO_POINTS 10
/** A cached rendezvous descriptor. */
typedef struct rend_cache_entry_t {
size_t len; /**< Length of <b>desc</b> */
time_t last_served; /**< When did we last write this one to somebody?
* (HSDir only) */
char *desc; /**< Service descriptor */
rend_service_descriptor_t *parsed; /**< Parsed value of 'desc' */
} rend_cache_entry_t;
void rend_cache_init(void);
void rend_cache_clean(time_t now);
void rend_cache_clean_v2_descs_as_dir(time_t now, size_t min_to_remove);
void rend_cache_purge(void);
void rend_cache_free_all(void);
int rend_cache_lookup_entry(const char *query, int version,
rend_cache_entry_t **entry_out);
int rend_cache_lookup_v2_desc_as_dir(const char *query, const char **desc);
/** Return value from rend_cache_store_v2_desc_as_{dir,client}. */
typedef enum {
RCS_NOTDIR = -2, /**< We're not a directory */
RCS_BADDESC = -1, /**< This descriptor is no good. */
RCS_OKAY = 0 /**< All worked as expected */
} rend_cache_store_status_t;
rend_cache_store_status_t rend_cache_store_v2_desc_as_dir(const char *desc);
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);
size_t rend_cache_get_total_allocation(void);
#endif /* TOR_RENDCACHE_H */

2
src/or/rendclient.h
View File

@ -12,6 +12,8 @@
#ifndef TOR_RENDCLIENT_H #ifndef TOR_RENDCLIENT_H
#define TOR_RENDCLIENT_H #define TOR_RENDCLIENT_H
#include "rendcache.h"
void rend_client_purge_state(void); void rend_client_purge_state(void);
void rend_client_introcirc_has_opened(origin_circuit_t *circ); void rend_client_introcirc_has_opened(origin_circuit_t *circ);

583
src/or/rendcommon.c
View File

@ -687,194 +687,6 @@ rend_get_service_id(crypto_pk_t *pk, char *out)
return 0; return 0;
} }
/* ==== Rendezvous service descriptor cache. */
/** How old do we let hidden service descriptors get before discarding
* them as too old? */
#define REND_CACHE_MAX_AGE (2*24*60*60)
/** How wrong do we assume our clock may be when checking whether hidden
* services are too old or too new? */
#define REND_CACHE_MAX_SKEW (24*60*60)
/** 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;
/** 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();
}
/** 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 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));
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_);
rend_cache = NULL;
rend_cache_v2_dir = NULL;
rend_cache_total_allocation = 0;
}
/** 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 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);
}
/** Determines whether <b>a</b> is in the interval of <b>b</b> (excluded) and /** Determines whether <b>a</b> is in the interval of <b>b</b> (excluded) and
* <b>c</b> (included) in a circular digest ring; returns 1 if this is the * <b>c</b> (included) in a circular digest ring; returns 1 if this is the
* case, and 0 otherwise. * case, and 0 otherwise.
@ -938,401 +750,6 @@ rend_valid_descriptor_id(const char *query)
return 0; return 0;
} }
/** 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;
}
/* Do not allow more than this many introduction points in a hidden service
* descriptor */
#define MAX_INTRO_POINTS 10
/** 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.");
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 already have a newer descriptor? */
tor_snprintf(key, sizeof(key), "2%s", service_id);
e = (rend_cache_entry_t*) strmap_get_lc(rend_cache, key);
if (e && e->parsed->timestamp > parsed->timestamp) {
log_info(LD_REND, "We already have a newer service descriptor for "
"service ID %s with the same desc ID and version.",
safe_str_client(service_id));
goto okay;
}
/* Do we already have this descriptor? */
if (e && !strcmp(desc, e->desc)) {
log_info(LD_REND,"We already have this service descriptor %s.",
safe_str_client(service_id));
goto okay;
}
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_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;
}
/** Called when we get a rendezvous-related relay cell on circuit /** Called when we get a rendezvous-related relay cell on circuit
* <b>circ</b>. Dispatch on rendezvous relay command. */ * <b>circ</b>. Dispatch on rendezvous relay command. */
void void

21
src/or/rendcommon.h
View File

@ -37,28 +37,8 @@ void rend_encoded_v2_service_descriptor_free(
rend_encoded_v2_service_descriptor_t *desc); rend_encoded_v2_service_descriptor_t *desc);
void rend_intro_point_free(rend_intro_point_t *intro); void rend_intro_point_free(rend_intro_point_t *intro);
void rend_cache_init(void);
void rend_cache_clean(time_t now);
void rend_cache_clean_v2_descs_as_dir(time_t now, size_t min_to_remove);
void rend_cache_purge(void);
void rend_cache_free_all(void);
int rend_valid_service_id(const char *query); int rend_valid_service_id(const char *query);
int rend_valid_descriptor_id(const char *query); int rend_valid_descriptor_id(const char *query);
int rend_cache_lookup_entry(const char *query, int version,
rend_cache_entry_t **entry_out);
int rend_cache_lookup_v2_desc_as_dir(const char *query, const char **desc);
/** Return value from rend_cache_store_v2_desc_as_{dir,client}. */
typedef enum {
RCS_NOTDIR = -2, /**< We're not a directory */
RCS_BADDESC = -1, /**< This descriptor is no good. */
RCS_OKAY = 0 /**< All worked as expected */
} rend_cache_store_status_t;
rend_cache_store_status_t rend_cache_store_v2_desc_as_dir(const char *desc);
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);
int rend_encode_v2_descriptors(smartlist_t *descs_out, int rend_encode_v2_descriptors(smartlist_t *descs_out,
rend_service_descriptor_t *desc, time_t now, rend_service_descriptor_t *desc, time_t now,
uint8_t period, rend_auth_type_t auth_type, uint8_t period, rend_auth_type_t auth_type,
@ -71,7 +51,6 @@ int rend_id_is_in_interval(const char *a, const char *b, const char *c);
void rend_get_descriptor_id_bytes(char *descriptor_id_out, void rend_get_descriptor_id_bytes(char *descriptor_id_out,
const char *service_id, const char *service_id,
const char *secret_id_part); const char *secret_id_part);
size_t rend_cache_get_total_allocation(void);
rend_data_t *rend_data_dup(const rend_data_t *data); rend_data_t *rend_data_dup(const rend_data_t *data);
rend_data_t *rend_data_client_create(const char *onion_address, rend_data_t *rend_data_client_create(const char *onion_address,