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commit c611e328de05685c6159a6c1a6bb8829b494c408 Author: David Goulet dgoulet@torproject.org AuthorDate: Mon Jun 27 15:17:54 2022 -0400
hs: Add data structure needed for PoW --- src/feature/hs/hs_cell.h | 1 + src/feature/hs/hs_descriptor.h | 1 + src/feature/hs/hs_pow.h | 113 +++++++++++++++++++++++++++++++++++++++++ src/feature/hs/include.am | 1 + 4 files changed, 116 insertions(+)
diff --git a/src/feature/hs/hs_cell.h b/src/feature/hs/hs_cell.h index 538a135491..2735401c05 100644 --- a/src/feature/hs/hs_cell.h +++ b/src/feature/hs/hs_cell.h @@ -11,6 +11,7 @@
#include "core/or/or.h" #include "feature/hs/hs_service.h" +#include "feature/hs/hs_pow.h"
/** An INTRODUCE1 cell requires at least this amount of bytes (see section * 3.2.2 of the specification). Below this value, the cell must be padded. */ diff --git a/src/feature/hs/hs_descriptor.h b/src/feature/hs/hs_descriptor.h index 8f42b2138b..fbfc4715a9 100644 --- a/src/feature/hs/hs_descriptor.h +++ b/src/feature/hs/hs_descriptor.h @@ -15,6 +15,7 @@ #include "trunnel/ed25519_cert.h" /* needed for trunnel */ #include "feature/nodelist/torcert.h" #include "core/crypto/hs_ntor.h" /* for hs_subcredential_t */ +#include "feature/hs/hs_pow.h"
/* Trunnel */ struct link_specifier_t; diff --git a/src/feature/hs/hs_pow.h b/src/feature/hs/hs_pow.h new file mode 100644 index 0000000000..2ad5c2b04c --- /dev/null +++ b/src/feature/hs/hs_pow.h @@ -0,0 +1,113 @@ +/* Copyright (c) 2019-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_pow.h + * \brief Header file containing PoW denial of service defenses for the HS + * subsystem for all versions. + **/ + +#ifndef TOR_HS_POW_H +#define TOR_HS_POW_H + +typedef unsigned __int128 uint128_t; + +#include "ext/equix/include/equix.h" + +#include "lib/evloop/compat_libevent.h" +#include "lib/smartlist_core/smartlist_core.h" + +#define HS_POW_SUGGESTED_EFFORT_DEFAULT 100 // HRPR TODO 5000 +/* Service updates the suggested effort every HS_UPDATE_PERIOD seconds. */ +#define HS_UPDATE_PERIOD 300 // HRPR TODO Should be consensus + +/** Length of random nonce (N) used in the PoW scheme. */ +#define HS_POW_NONCE_LEN 16 +/** Length of an E-quiX solution (S) in bytes. */ +#define HS_POW_EQX_SOL_LEN 16 +/** Length of blake2b hash result (R) used in the PoW scheme. */ +#define HS_POW_HASH_LEN 4 +/** Length of random seed used in the PoW scheme. */ +#define HS_POW_SEED_LEN 32 +/** Length of an effort value */ +#define HS_POW_EFFORT_LEN sizeof(uint32_t) +/** Length of a PoW challenge. Construction as per prop327 is: + * (C || N || INT_32(E)) + */ +#define HS_POW_CHALLENGE_LEN \ + (HS_POW_SEED_LEN + HS_POW_NONCE_LEN + HS_POW_EFFORT_LEN) + +/** Proof-of-Work parameters for DoS defense located in a descriptor. */ +typedef struct hs_pow_desc_params_t { + /** Type of PoW system being used, for example "v1". */ + char *type; + + /** Random 32-byte seed used as input the the PoW hash function. Decoded? */ + uint8_t seed[HS_POW_SEED_LEN]; + + /** Specifies effort value that clients should aim for when contacting the + * service. */ + uint32_t suggested_effort; + + /** Timestamp after which the above seed expires. */ + time_t expiration_time; +} hs_pow_desc_params_t; + +/** State and parameters of PoW defenses, stored in the service state. */ +typedef struct hs_pow_service_state_t { + /* If PoW defenses are enabled this is a priority queue containing acceptable + * requests that are awaiting rendezvous circuits to built, where priority is + * based on the amount of effort that was exerted in the PoW. */ + smartlist_t *rend_request_pqueue; + + /* HRPR TODO Is this cursed? Including compat_libevent for this. feb 24 */ + /* When PoW defenses are enabled, this event pops rendezvous requests from + * the service's priority queue; higher effort is higher priority. */ + mainloop_event_t *pop_pqueue_ev; + + /* The current seed being used in the PoW defenses. */ + uint8_t seed_current[HS_POW_SEED_LEN]; + + /* The previous seed that was used in the PoW defenses. We accept solutions + * for both the current and previous seed. */ + uint8_t seed_previous[HS_POW_SEED_LEN]; + + /* The time at which the current seed expires and rotates for a new one. */ + time_t expiration_time; + + /* The minimum effort required for a valid solution. */ + uint32_t min_effort; + + /* The suggested effort that clients should use in order for their request to + * be serviced in a timely manner. */ + uint32_t suggested_effort; + + /* The following values are used when calculating and updating the suggested + * effort every HS_UPDATE_PERIOD seconds. */ + + /* Number of intro requests the service can handle per second. */ + uint32_t svc_bottom_capacity; + /* The next time at which to update the suggested effort. */ + time_t next_effort_update; + /* Sum of effort of all valid requests received since the last update. */ + uint64_t total_effort; +} hs_pow_service_state_t; + +/* Struct to store a solution to the PoW challenge. */ +typedef struct hs_pow_solution_t { + /** HRPR TODO are we best off storing this as a byte array, as trunnel doesnt + * support uint128 (?) */ + /* The 16 byte nonce used in the solution. */ + uint128_t nonce; + + /* The effort used in the solution. */ + uint32_t effort; + + /* The first four bytes of the seed used in the solution. */ + uint32_t seed_head; + + /* The Equi-X solution used in the solution. */ + equix_solution equix_solution; +} hs_pow_solution_t; + +#endif /* !defined(TOR_HS_POW_H) */ diff --git a/src/feature/hs/include.am b/src/feature/hs/include.am index c55abd3d47..efe85543cd 100644 --- a/src/feature/hs/include.am +++ b/src/feature/hs/include.am @@ -38,6 +38,7 @@ noinst_HEADERS += \ src/feature/hs/hs_ob.h \ src/feature/hs/hs_opts_st.h \ src/feature/hs/hs_options.inc \ + src/feature/hs/hs_pow.h \ src/feature/hs/hs_service.h \ src/feature/hs/hs_stats.h \ src/feature/hs/hsdir_index_st.h \