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Merge branch 'maint-0.3.5'
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@dgoulet-tor
dgoulet-tor committed Oct 30, 2018
2 parents 124c437 + 488969f commit aa1ae13
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Showing 4 changed files with 135 additions and 79 deletions.
4 changes: 4 additions & 0 deletions changes/ticket27838
View file
@@ -0,0 +1,4 @@
o Minor bugfixes (hidden service v3):
- Build the service descriptor signing key certificate before uploading so
we always have a fresh one leaving no chances for it to expire service
side. Fixes bug 27838; bugfix on 0.3.2.1-alpha.
134 changes: 85 additions & 49 deletions src/feature/hs/hs_service.c
View file
Expand Up @@ -1696,6 +1696,32 @@ build_desc_intro_points(const hs_service_t *service,
} DIGEST256MAP_FOREACH_END;
}

/* Build the descriptor signing key certificate. */
static void
build_desc_signing_key_cert(hs_service_descriptor_t *desc, time_t now)
{
hs_desc_plaintext_data_t *plaintext;

tor_assert(desc);
tor_assert(desc->desc);

/* Ease our life a bit. */
plaintext = &desc->desc->plaintext_data;

/* Get rid of what we have right now. */
tor_cert_free(plaintext->signing_key_cert);

/* Fresh certificate for the signing key. */
plaintext->signing_key_cert =
tor_cert_create(&desc->blinded_kp, CERT_TYPE_SIGNING_HS_DESC,
&desc->signing_kp.pubkey, now, HS_DESC_CERT_LIFETIME,
CERT_FLAG_INCLUDE_SIGNING_KEY);
/* If the cert creation fails, the descriptor encoding will fail and thus
* ultimately won't be uploaded. We'll get a stack trace to help us learn
* where the call came from and the tor_cert_create() will log the error. */
tor_assert_nonfatal(plaintext->signing_key_cert);
}

/* Populate the descriptor encrypted section from the given service object.
* This will generate a valid list of introduction points that can be used
* after for circuit creation. Return 0 on success else -1 on error. */
Expand Down Expand Up @@ -1811,17 +1837,15 @@ build_service_desc_superencrypted(const hs_service_t *service,

/* Populate the descriptor plaintext section from the given service object.
* The caller must make sure that the keys in the descriptors are valid that
* is are non-zero. Return 0 on success else -1 on error. */
static int
* is are non-zero. This can't fail. */
static void
build_service_desc_plaintext(const hs_service_t *service,
hs_service_descriptor_t *desc, time_t now)
hs_service_descriptor_t *desc)
{
int ret = -1;
hs_desc_plaintext_data_t *plaintext;

tor_assert(service);
tor_assert(desc);
/* XXX: Use a "assert_desc_ok()" ? */
tor_assert(!tor_mem_is_zero((char *) &desc->blinded_kp,
sizeof(desc->blinded_kp)));
tor_assert(!tor_mem_is_zero((char *) &desc->signing_kp,
Expand All @@ -1835,24 +1859,13 @@ build_service_desc_plaintext(const hs_service_t *service,

plaintext->version = service->config.version;
plaintext->lifetime_sec = HS_DESC_DEFAULT_LIFETIME;
plaintext->signing_key_cert =
tor_cert_create(&desc->blinded_kp, CERT_TYPE_SIGNING_HS_DESC,
&desc->signing_kp.pubkey, now, HS_DESC_CERT_LIFETIME,
CERT_FLAG_INCLUDE_SIGNING_KEY);
if (plaintext->signing_key_cert == NULL) {
log_warn(LD_REND, "Unable to create descriptor signing certificate for "
"service %s",
safe_str_client(service->onion_address));
goto end;
}
/* Copy public key material to go in the descriptor. */
ed25519_pubkey_copy(&plaintext->signing_pubkey, &desc->signing_kp.pubkey);
ed25519_pubkey_copy(&plaintext->blinded_pubkey, &desc->blinded_kp.pubkey);
/* Success. */
ret = 0;

end:
return ret;
/* Create the signing key certificate. This will be updated before each
* upload but we create it here so we don't complexify our unit tests. */
build_desc_signing_key_cert(desc, approx_time());
}

/** Compute the descriptor's OPE cipher for encrypting revision counters. */
Expand Down Expand Up @@ -1942,8 +1955,7 @@ build_service_desc_keys(const hs_service_t *service,
*
* This can error if we are unable to create keys or certificate. */
static void
build_service_descriptor(hs_service_t *service, time_t now,
uint64_t time_period_num,
build_service_descriptor(hs_service_t *service, uint64_t time_period_num,
hs_service_descriptor_t **desc_out)
{
char *encoded_desc;
Expand All @@ -1962,9 +1974,8 @@ build_service_descriptor(hs_service_t *service, time_t now,
goto err;
}
/* Setup plaintext descriptor content. */
if (build_service_desc_plaintext(service, desc, now) < 0) {
goto err;
}
build_service_desc_plaintext(service, desc);

/* Setup superencrypted descriptor content. */
if (build_service_desc_superencrypted(service, desc) < 0) {
goto err;
Expand Down Expand Up @@ -2037,10 +2048,8 @@ build_descriptors_for_new_service(hs_service_t *service, time_t now)
}

/* Build descriptors. */
build_service_descriptor(service, now, current_desc_tp,
&service->desc_current);
build_service_descriptor(service, now, next_desc_tp,
&service->desc_next);
build_service_descriptor(service, current_desc_tp, &service->desc_current);
build_service_descriptor(service, next_desc_tp, &service->desc_next);
log_info(LD_REND, "Hidden service %s has just started. Both descriptors "
"built. Now scheduled for upload.",
safe_str_client(service->onion_address));
Expand Down Expand Up @@ -2070,7 +2079,7 @@ build_all_descriptors(time_t now)
}

if (service->desc_next == NULL) {
build_service_descriptor(service, now, hs_get_next_time_period_num(0),
build_service_descriptor(service, hs_get_next_time_period_num(0),
&service->desc_next);
log_info(LD_REND, "Hidden service %s next descriptor successfully "
"built. Now scheduled for upload.",
Expand Down Expand Up @@ -2282,12 +2291,9 @@ service_desc_schedule_upload(hs_service_descriptor_t *desc,
}
}

/* Update the given descriptor from the given service. The possible update
* actions includes:
* - Picking missing intro points if needed.
*/
/* Pick missing intro points for this descriptor if needed. */
static void
update_service_descriptor(hs_service_t *service,
update_service_descriptor_intro_points(hs_service_t *service,
hs_service_descriptor_t *desc, time_t now)
{
unsigned int num_intro_points;
Expand Down Expand Up @@ -2326,15 +2332,17 @@ update_service_descriptor(hs_service_t *service,
}
}

/* Update descriptors for each service if needed. */
/* Update descriptor intro points for each service if needed. We do this as
* part of the periodic event because we need to establish intro point circuits
* before we publish descriptors. */
STATIC void
update_all_descriptors(time_t now)
update_all_descriptors_intro_points(time_t now)
{
FOR_EACH_SERVICE_BEGIN(service) {
/* We'll try to update each descriptor that is if certain conditions apply
* in order for the descriptor to be updated. */
FOR_EACH_DESCRIPTOR_BEGIN(service, desc) {
update_service_descriptor(service, desc, now);
update_service_descriptor_intro_points(service, desc, now);
} FOR_EACH_DESCRIPTOR_END;
} FOR_EACH_SERVICE_END;
}
Expand Down Expand Up @@ -2619,10 +2627,10 @@ run_build_descriptor_event(time_t now)
* been rotated or we just started up. */
build_all_descriptors(now);

/* Finally, we'll check if we should update the descriptors. Missing
* introduction points will be picked in this function which is useful for
* newly built descriptors. */
update_all_descriptors(now);
/* Finally, we'll check if we should update the descriptors' intro
* points. Missing introduction points will be picked in this function which
* is useful for newly built descriptors. */
update_all_descriptors_intro_points(now);
}

/* For the given service, launch any intro point circuits that could be
Expand Down Expand Up @@ -3083,6 +3091,37 @@ should_service_upload_descriptor(const hs_service_t *service,
return 0;
}

/* Refresh the given service descriptor meaning this will update every mutable
* field that needs to be updated before we upload.
*
* This should ONLY be called before uploading a descriptor. It assumes that
* the descriptor has been built (desc->desc) and that all intro point
* circuits have been established. */
static void
refresh_service_descriptor(const hs_service_t *service,
hs_service_descriptor_t *desc, time_t now)
{
/* There are few fields that we consider "mutable" in the descriptor meaning
* we need to update them regurlarly over the lifetime fo the descriptor.
* The rest are set once and should not be modified.
*
* - Signing key certificate.
* - Revision counter.
* - Introduction points which includes many thing. See
* hs_desc_intro_point_t. and the setup_desc_intro_point() function.
*/

/* Create the signing key certificate. */
build_desc_signing_key_cert(desc, now);

/* Build the intro points descriptor section. The refresh step is just
* before we upload so all circuits have been properly established. */
build_desc_intro_points(service, desc, now);

/* Set the desc revision counter right before uploading */
set_descriptor_revision_counter(desc, now, service->desc_current == desc);
}

/* Scheduled event run from the main loop. Try to upload the descriptor for
* each service. */
STATIC void
Expand Down Expand Up @@ -3118,15 +3157,12 @@ run_upload_descriptor_event(time_t now)
service->config.num_intro_points,
(desc->missing_intro_points) ? " (couldn't pick more)" : "");

/* At this point, we have to upload the descriptor so start by building
* the intro points descriptor section which we are now sure to be
* accurate because all circuits have been established. */
build_desc_intro_points(service, desc, now);

/* Set the desc revision counter right before uploading */
set_descriptor_revision_counter(desc, approx_time(),
service->desc_current == desc);
/* We are about to upload so we need to do one last step which is to
* update the service's descriptor mutable fields in order to upload a
* coherent descriptor. */
refresh_service_descriptor(service, desc, now);

/* Proceed with the upload, the descriptor is ready to be encoded. */
upload_descriptor_to_all(service, desc);
} FOR_EACH_DESCRIPTOR_END;
} FOR_EACH_SERVICE_END;
Expand Down
72 changes: 44 additions & 28 deletions src/feature/hs/hs_service.h
View file
Expand Up @@ -99,49 +99,65 @@ typedef struct hs_service_intropoints_t {
digestmap_t *failed_id;
} hs_service_intropoints_t;

/* Representation of a service descriptor. */
/* Representation of a service descriptor.
*
* Some elements of the descriptor are mutable whereas others are immutable:
* Immutable elements are initialized once when the descriptor is built (when
* service descriptors gets rotated). This means that these elements are
* initialized once and then they don't change for the lifetime of the
* descriptor. See build_service_descriptor().
*
* Mutable elements are initialized when we build the descriptor but they are
* also altered during the lifetime of the descriptor. They could be
* _refreshed_ everytime we upload the descriptor (which happens multiple times
* over the lifetime of the descriptor), or through periodic events. We do this
* for elements like the descriptor revision counter and various
* certificates. See refresh_service_descriptor() and
* update_service_descriptor_intro_points().
*/
typedef struct hs_service_descriptor_t {
/* Decoded descriptor. This object is used for encoding when the service
* publishes the descriptor. */
hs_descriptor_t *desc;

/* Client authorization ephemeral keypair. */
/* Immutable: Client authorization ephemeral keypair. */
curve25519_keypair_t auth_ephemeral_kp;

/* Descriptor cookie used to encrypt the descriptor, when the client
* authorization is enabled */
/* Immutable: Descriptor cookie used to encrypt the descriptor, when the
* client authorization is enabled */
uint8_t descriptor_cookie[HS_DESC_DESCRIPTOR_COOKIE_LEN];

/* Descriptor signing keypair. */
/* Immutable: Descriptor signing keypair. */
ed25519_keypair_t signing_kp;

/* Blinded keypair derived from the master identity public key. */
/* Immutable: Blinded keypair derived from the master identity public key. */
ed25519_keypair_t blinded_kp;

/* When is the next time when we should upload the descriptor. */
/* Immutable: The time period number this descriptor has been created for. */
uint64_t time_period_num;

/** Immutable: The OPE cipher for encrypting revision counters for this
* descriptor. Tied to the descriptor blinded key. */
struct crypto_ope_t *ope_cipher;

/* Mutable: Decoded descriptor. This object is used for encoding when the
* service publishes the descriptor. */
hs_descriptor_t *desc;

/* Mutable: When is the next time when we should upload the descriptor. */
time_t next_upload_time;

/* Introduction points assign to this descriptor which contains
* hs_service_intropoints_t object indexed by authentication key (the RSA
* key if the node is legacy). */
/* Mutable: Introduction points assign to this descriptor which contains
* hs_service_intropoints_t object indexed by authentication key (the RSA key
* if the node is legacy). */
hs_service_intropoints_t intro_points;

/* The time period number this descriptor has been created for. */
uint64_t time_period_num;

/* True iff we have missing intro points for this descriptor because we
* couldn't pick any nodes. */
/* Mutable: True iff we have missing intro points for this descriptor because
* we couldn't pick any nodes. */
unsigned int missing_intro_points : 1;

/** List of the responsible HSDirs (their b64ed identity digest) last time we
* uploaded this descriptor. If the set of responsible HSDirs is different
* from this list, this means we received new dirinfo and we need to
* reupload our descriptor. */
/** Mutable: List of the responsible HSDirs (their b64ed identity digest)
* last time we uploaded this descriptor. If the set of responsible HSDirs
* is different from this list, this means we received new dirinfo and we
* need to reupload our descriptor. */
smartlist_t *previous_hsdirs;

/** The OPE cipher for encrypting revision counters for this descriptor.
* Tied to the descriptor blinded key. */
struct crypto_ope_t *ope_cipher;
} hs_service_descriptor_t;

/* Service key material. */
Expand Down Expand Up @@ -390,7 +406,7 @@ STATIC int intro_point_should_expire(const hs_service_intro_point_t *ip,
STATIC void run_housekeeping_event(time_t now);
STATIC void rotate_all_descriptors(time_t now);
STATIC void build_all_descriptors(time_t now);
STATIC void update_all_descriptors(time_t now);
STATIC void update_all_descriptors_intro_points(time_t now);
STATIC void run_upload_descriptor_event(time_t now);

STATIC void service_descriptor_free_(hs_service_descriptor_t *desc);
Expand Down
4 changes: 2 additions & 2 deletions src/test/test_hs_service.c
View file
Expand Up @@ -1457,7 +1457,7 @@ test_build_update_descriptors(void *arg)
/* Time to test the update of those descriptors. At first, we have no node
* in the routerlist so this will find NO suitable node for the IPs. */
setup_full_capture_of_logs(LOG_INFO);
update_all_descriptors(now);
update_all_descriptors_intro_points(now);
expect_log_msg_containing("Unable to find a suitable node to be an "
"introduction point for service");
teardown_capture_of_logs();
Expand Down Expand Up @@ -1508,7 +1508,7 @@ test_build_update_descriptors(void *arg)

/* We expect to pick only one intro point from the node above. */
setup_full_capture_of_logs(LOG_INFO);
update_all_descriptors(now);
update_all_descriptors_intro_points(now);
tor_free(node->ri->onion_curve25519_pkey); /* Avoid memleak. */
tor_free(node->ri->cache_info.signing_key_cert);
tor_free(node->ri->onion_pkey);
Expand Down

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