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authorNick Mathewson <nickm@torproject.org>2018-06-21 12:46:11 -0400
committerNick Mathewson <nickm@torproject.org>2018-06-21 13:14:14 -0400
commit25ccfff86a5b29c9c1ec9b3d01fe1dc796e9afa0 (patch)
tree1c23ec9dd2cea5d00e4262fa4574ffdb9e250aa7 /src/common/crypto_ed25519.c
parent49d7c9ce53daa13daae59eedceb07d28e06e4395 (diff)
downloadtor-25ccfff86a5b29c9c1ec9b3d01fe1dc796e9afa0.tar.gz
tor-25ccfff86a5b29c9c1ec9b3d01fe1dc796e9afa0.zip
Split crypto and tls libraries into directories
I am calling the crypto library "crypt_ops", since I want higher-level crypto things to be separated from lower-level ones. This library will hold only the low-level ones, once we have it refactored.
Diffstat (limited to 'src/common/crypto_ed25519.c')
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diff --git a/src/common/crypto_ed25519.c b/src/common/crypto_ed25519.c
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-/* Copyright (c) 2013-2018, The Tor Project, Inc. */
-/* See LICENSE for licensing information */
-
-/**
- * \file crypto_ed25519.c
- *
- * \brief Wrapper code for an ed25519 implementation.
- *
- * Ed25519 is a Schnorr signature on a Twisted Edwards curve, defined
- * by Dan Bernstein. For more information, see https://ed25519.cr.yp.to/
- *
- * This module wraps our choice of Ed25519 backend, and provides a few
- * convenience functions for checking and generating signatures. It also
- * provides Tor-specific tools for key blinding and for converting Ed25519
- * keys to and from the corresponding Curve25519 keys.
- */
-
-#define CRYPTO_ED25519_PRIVATE
-#include "orconfig.h"
-#ifdef HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-
-#include "common/crypto_curve25519.h"
-#include "common/crypto_digest.h"
-#include "common/crypto_ed25519.h"
-#include "common/crypto_format.h"
-#include "common/crypto_rand.h"
-#include "common/crypto_util.h"
-#include "common/torlog.h"
-#include "common/util.h"
-#include "common/util_format.h"
-
-#include "ed25519/ref10/ed25519_ref10.h"
-#include "ed25519/donna/ed25519_donna_tor.h"
-
-static void pick_ed25519_impl(void);
-
-/** An Ed25519 implementation, as a set of function pointers. */
-typedef struct {
- int (*selftest)(void);
-
- int (*seckey)(unsigned char *);
- int (*seckey_expand)(unsigned char *, const unsigned char *);
- int (*pubkey)(unsigned char *, const unsigned char *);
- int (*keygen)(unsigned char *, unsigned char *);
-
- int (*open)(const unsigned char *, const unsigned char *, size_t, const
- unsigned char *);
- int (*sign)(unsigned char *, const unsigned char *, size_t,
- const unsigned char *, const unsigned char *);
- int (*open_batch)(const unsigned char **, size_t *, const unsigned char **,
- const unsigned char **, size_t, int *);
-
- int (*blind_secret_key)(unsigned char *, const unsigned char *,
- const unsigned char *);
- int (*blind_public_key)(unsigned char *, const unsigned char *,
- const unsigned char *);
-
- int (*pubkey_from_curve25519_pubkey)(unsigned char *, const unsigned char *,
- int);
-
- int (*ed25519_scalarmult_with_group_order)(unsigned char *,
- const unsigned char *);
-} ed25519_impl_t;
-
-/** The Ref10 Ed25519 implementation. This one is pure C and lightly
- * optimized. */
-static const ed25519_impl_t impl_ref10 = {
- NULL,
-
- ed25519_ref10_seckey,
- ed25519_ref10_seckey_expand,
- ed25519_ref10_pubkey,
- ed25519_ref10_keygen,
-
- ed25519_ref10_open,
- ed25519_ref10_sign,
- NULL,
-
- ed25519_ref10_blind_secret_key,
- ed25519_ref10_blind_public_key,
-
- ed25519_ref10_pubkey_from_curve25519_pubkey,
- ed25519_ref10_scalarmult_with_group_order,
-};
-
-/** The Ref10 Ed25519 implementation. This one is heavily optimized, but still
- * mostly C. The C still tends to be heavily platform-specific. */
-static const ed25519_impl_t impl_donna = {
- ed25519_donna_selftest,
-
- ed25519_donna_seckey,
- ed25519_donna_seckey_expand,
- ed25519_donna_pubkey,
- ed25519_donna_keygen,
-
- ed25519_donna_open,
- ed25519_donna_sign,
- ed25519_sign_open_batch_donna,
-
- ed25519_donna_blind_secret_key,
- ed25519_donna_blind_public_key,
-
- ed25519_donna_pubkey_from_curve25519_pubkey,
- ed25519_donna_scalarmult_with_group_order,
-};
-
-/** Which Ed25519 implementation are we using? NULL if we haven't decided
- * yet. */
-static const ed25519_impl_t *ed25519_impl = NULL;
-
-/** Helper: Return our chosen Ed25519 implementation.
- *
- * This should only be called after we've picked an implementation, but
- * it _does_ recover if you forget this.
- **/
-static inline const ed25519_impl_t *
-get_ed_impl(void)
-{
- if (BUG(ed25519_impl == NULL)) {
- pick_ed25519_impl(); // LCOV_EXCL_LINE - We always call ed25519_init().
- }
- return ed25519_impl;
-}
-
-#ifdef TOR_UNIT_TESTS
-/** For testing: used to remember our actual choice of Ed25519
- * implementation */
-static const ed25519_impl_t *saved_ed25519_impl = NULL;
-/** For testing: Use the Ed25519 implementation called <b>name</b> until
- * crypto_ed25519_testing_restore_impl is called. Recognized names are
- * "donna" and "ref10". */
-void
-crypto_ed25519_testing_force_impl(const char *name)
-{
- tor_assert(saved_ed25519_impl == NULL);
- saved_ed25519_impl = ed25519_impl;
- if (! strcmp(name, "donna")) {
- ed25519_impl = &impl_donna;
- } else {
- tor_assert(!strcmp(name, "ref10"));
- ed25519_impl = &impl_ref10;
- }
-}
-/** For testing: go back to whatever Ed25519 implementation we had picked
- * before crypto_ed25519_testing_force_impl was called.
- */
-void
-crypto_ed25519_testing_restore_impl(void)
-{
- ed25519_impl = saved_ed25519_impl;
- saved_ed25519_impl = NULL;
-}
-#endif /* defined(TOR_UNIT_TESTS) */
-
-/**
- * Initialize a new ed25519 secret key in <b>seckey_out</b>. If
- * <b>extra_strong</b>, take the RNG inputs directly from the operating
- * system. Return 0 on success, -1 on failure.
- */
-int
-ed25519_secret_key_generate(ed25519_secret_key_t *seckey_out,
- int extra_strong)
-{
- int r;
- uint8_t seed[32];
- if (extra_strong)
- crypto_strongest_rand(seed, sizeof(seed));
- else
- crypto_rand((char*)seed, sizeof(seed));
-
- r = get_ed_impl()->seckey_expand(seckey_out->seckey, seed);
- memwipe(seed, 0, sizeof(seed));
-
- return r < 0 ? -1 : 0;
-}
-
-/**
- * Given a 32-byte random seed in <b>seed</b>, expand it into an ed25519
- * secret key in <b>seckey_out</b>. Return 0 on success, -1 on failure.
- */
-int
-ed25519_secret_key_from_seed(ed25519_secret_key_t *seckey_out,
- const uint8_t *seed)
-{
- if (get_ed_impl()->seckey_expand(seckey_out->seckey, seed) < 0)
- return -1;
- return 0;
-}
-
-/**
- * Given a secret key in <b>seckey</b>, expand it into an
- * ed25519 public key. Return 0 on success, -1 on failure.
- */
-int
-ed25519_public_key_generate(ed25519_public_key_t *pubkey_out,
- const ed25519_secret_key_t *seckey)
-{
- if (get_ed_impl()->pubkey(pubkey_out->pubkey, seckey->seckey) < 0)
- return -1;
- return 0;
-}
-
-/** Generate a new ed25519 keypair in <b>keypair_out</b>. If
- * <b>extra_strong</b> is set, try to mix some system entropy into the key
- * generation process. Return 0 on success, -1 on failure. */
-int
-ed25519_keypair_generate(ed25519_keypair_t *keypair_out, int extra_strong)
-{
- if (ed25519_secret_key_generate(&keypair_out->seckey, extra_strong) < 0)
- return -1;
- if (ed25519_public_key_generate(&keypair_out->pubkey,
- &keypair_out->seckey)<0)
- return -1;
- return 0;
-}
-
-/** Return true iff 'pubkey' is set to zero (eg to indicate that it is not
- * set). */
-int
-ed25519_public_key_is_zero(const ed25519_public_key_t *pubkey)
-{
- return tor_mem_is_zero((char*)pubkey->pubkey, ED25519_PUBKEY_LEN);
-}
-
-/* Return a heap-allocated array that contains <b>msg</b> prefixed by the
- * string <b>prefix_str</b>. Set <b>final_msg_len_out</b> to the size of the
- * final array. If an error occurred, return NULL. It's the responsibility of
- * the caller to free the returned array. */
-static uint8_t *
-get_prefixed_msg(const uint8_t *msg, size_t msg_len,
- const char *prefix_str,
- size_t *final_msg_len_out)
-{
- size_t prefixed_msg_len, prefix_len;
- uint8_t *prefixed_msg;
-
- tor_assert(prefix_str);
- tor_assert(final_msg_len_out);
-
- prefix_len = strlen(prefix_str);
-
- /* msg_len + strlen(prefix_str) must not overflow. */
- if (msg_len > SIZE_T_CEILING - prefix_len) {
- return NULL;
- }
-
- prefixed_msg_len = msg_len + prefix_len;
- prefixed_msg = tor_malloc_zero(prefixed_msg_len);
-
- memcpy(prefixed_msg, prefix_str, prefix_len);
- memcpy(prefixed_msg + prefix_len, msg, msg_len);
-
- *final_msg_len_out = prefixed_msg_len;
- return prefixed_msg;
-}
-
-/**
- * Set <b>signature_out</b> to a signature of the <b>len</b>-byte message
- * <b>msg</b>, using the secret and public key in <b>keypair</b>.
- *
- * Return 0 if we successfully signed the message, otherwise return -1.
- */
-int
-ed25519_sign(ed25519_signature_t *signature_out,
- const uint8_t *msg, size_t len,
- const ed25519_keypair_t *keypair)
-{
- if (get_ed_impl()->sign(signature_out->sig, msg, len,
- keypair->seckey.seckey,
- keypair->pubkey.pubkey) < 0) {
- return -1;
- }
-
- return 0;
-}
-
-/**
- * Like ed25519_sign(), but also prefix <b>msg</b> with <b>prefix_str</b>
- * before signing. <b>prefix_str</b> must be a NUL-terminated string.
- */
-MOCK_IMPL(int,
-ed25519_sign_prefixed,(ed25519_signature_t *signature_out,
- const uint8_t *msg, size_t msg_len,
- const char *prefix_str,
- const ed25519_keypair_t *keypair))
-{
- int retval;
- size_t prefixed_msg_len;
- uint8_t *prefixed_msg;
-
- tor_assert(prefix_str);
-
- prefixed_msg = get_prefixed_msg(msg, msg_len, prefix_str,
- &prefixed_msg_len);
- if (BUG(!prefixed_msg)) {
- /* LCOV_EXCL_START -- only possible when the message and prefix are
- * ridiculously huge */
- log_warn(LD_GENERAL, "Failed to get prefixed msg.");
- return -1;
- /* LCOV_EXCL_STOP */
- }
-
- retval = ed25519_sign(signature_out,
- prefixed_msg, prefixed_msg_len,
- keypair);
- tor_free(prefixed_msg);
-
- return retval;
-}
-
-/**
- * Check whether if <b>signature</b> is a valid signature for the
- * <b>len</b>-byte message in <b>msg</b> made with the key <b>pubkey</b>.
- *
- * Return 0 if the signature is valid; -1 if it isn't.
- */
-MOCK_IMPL(int,
-ed25519_checksig,(const ed25519_signature_t *signature,
- const uint8_t *msg, size_t len,
- const ed25519_public_key_t *pubkey))
-{
- return
- get_ed_impl()->open(signature->sig, msg, len, pubkey->pubkey) < 0 ? -1 : 0;
-}
-
-/**
- * Like ed2519_checksig(), but also prefix <b>msg</b> with <b>prefix_str</b>
- * before verifying signature. <b>prefix_str</b> must be a NUL-terminated
- * string.
- */
-int
-ed25519_checksig_prefixed(const ed25519_signature_t *signature,
- const uint8_t *msg, size_t msg_len,
- const char *prefix_str,
- const ed25519_public_key_t *pubkey)
-{
- int retval;
- size_t prefixed_msg_len;
- uint8_t *prefixed_msg;
-
- prefixed_msg = get_prefixed_msg(msg, msg_len, prefix_str,
- &prefixed_msg_len);
- if (BUG(!prefixed_msg)) {
- /* LCOV_EXCL_START -- only possible when the message and prefix are
- * ridiculously huge */
- log_warn(LD_GENERAL, "Failed to get prefixed msg.");
- return -1;
- /* LCOV_EXCL_STOP */
- }
-
- retval = ed25519_checksig(signature,
- prefixed_msg, prefixed_msg_len,
- pubkey);
- tor_free(prefixed_msg);
-
- return retval;
-}
-
-/** Validate every signature among those in <b>checkable</b>, which contains
- * exactly <b>n_checkable</b> elements. If <b>okay_out</b> is non-NULL, set
- * the i'th element of <b>okay_out</b> to 1 if the i'th element of
- * <b>checkable</b> is valid, and to 0 otherwise. Return 0 if every signature
- * was valid. Otherwise return -N, where N is the number of invalid
- * signatures.
- */
-MOCK_IMPL(int,
-ed25519_checksig_batch,(int *okay_out,
- const ed25519_checkable_t *checkable,
- int n_checkable))
-{
- int i, res;
- const ed25519_impl_t *impl = get_ed_impl();
-
- if (impl->open_batch == NULL) {
- /* No batch verification implementation available, fake it by checking the
- * each signature individually.
- */
- res = 0;
- for (i = 0; i < n_checkable; ++i) {
- const ed25519_checkable_t *ch = &checkable[i];
- int r = ed25519_checksig(&ch->signature, ch->msg, ch->len, ch->pubkey);
- if (r < 0)
- --res;
- if (okay_out)
- okay_out[i] = (r == 0);
- }
- } else {
- /* ed25519-donna style batch verification available.
- *
- * Theoretically, this should only be called if n_checkable >= 3, since
- * that's the threshold where the batch verification actually kicks in,
- * but the only difference is a few mallocs/frees.
- */
- const uint8_t **ms;
- size_t *lens;
- const uint8_t **pks;
- const uint8_t **sigs;
- int *oks;
- int all_ok;
-
- ms = tor_calloc(n_checkable, sizeof(uint8_t*));
- lens = tor_calloc(n_checkable, sizeof(size_t));
- pks = tor_calloc(n_checkable, sizeof(uint8_t*));
- sigs = tor_calloc(n_checkable, sizeof(uint8_t*));
- oks = okay_out ? okay_out : tor_calloc(n_checkable, sizeof(int));
-
- for (i = 0; i < n_checkable; ++i) {
- ms[i] = checkable[i].msg;
- lens[i] = checkable[i].len;
- pks[i] = checkable[i].pubkey->pubkey;
- sigs[i] = checkable[i].signature.sig;
- oks[i] = 0;
- }
-
- res = 0;
- all_ok = impl->open_batch(ms, lens, pks, sigs, n_checkable, oks);
- for (i = 0; i < n_checkable; ++i) {
- if (!oks[i])
- --res;
- }
- /* XXX: For now sanity check oks with the return value. Once we have
- * more confidence in the code, if `all_ok == 0` we can skip iterating
- * over oks since all the signatures were found to be valid.
- */
- tor_assert(((res == 0) && !all_ok) || ((res < 0) && all_ok));
-
- tor_free(ms);
- tor_free(lens);
- tor_free(pks);
- tor_free(sigs);
- if (! okay_out)
- tor_free(oks);
- }
-
- return res;
-}
-
-/**
- * Given a curve25519 keypair in <b>inp</b>, generate a corresponding
- * ed25519 keypair in <b>out</b>, and set <b>signbit_out</b> to the
- * sign bit of the X coordinate of the ed25519 key.
- *
- * NOTE THAT IT IS PROBABLY NOT SAFE TO USE THE GENERATED KEY FOR ANYTHING
- * OUTSIDE OF WHAT'S PRESENTED IN PROPOSAL 228. In particular, it's probably
- * not a great idea to use it to sign attacker-supplied anything.
- */
-int
-ed25519_keypair_from_curve25519_keypair(ed25519_keypair_t *out,
- int *signbit_out,
- const curve25519_keypair_t *inp)
-{
- const char string[] = "Derive high part of ed25519 key from curve25519 key";
- ed25519_public_key_t pubkey_check;
- crypto_digest_t *ctx;
- uint8_t sha512_output[DIGEST512_LEN];
-
- memcpy(out->seckey.seckey, inp->seckey.secret_key, 32);
-
- ctx = crypto_digest512_new(DIGEST_SHA512);
- crypto_digest_add_bytes(ctx, (const char*)out->seckey.seckey, 32);
- crypto_digest_add_bytes(ctx, (const char*)string, sizeof(string));
- crypto_digest_get_digest(ctx, (char *)sha512_output, sizeof(sha512_output));
- crypto_digest_free(ctx);
- memcpy(out->seckey.seckey + 32, sha512_output, 32);
-
- ed25519_public_key_generate(&out->pubkey, &out->seckey);
-
- *signbit_out = out->pubkey.pubkey[31] >> 7;
-
- ed25519_public_key_from_curve25519_public_key(&pubkey_check, &inp->pubkey,
- *signbit_out);
-
- tor_assert(fast_memeq(pubkey_check.pubkey, out->pubkey.pubkey, 32));
-
- memwipe(&pubkey_check, 0, sizeof(pubkey_check));
- memwipe(sha512_output, 0, sizeof(sha512_output));
-
- return 0;
-}
-
-/**
- * Given a curve25519 public key and sign bit of X coordinate of the ed25519
- * public key, generate the corresponding ed25519 public key.
- */
-int
-ed25519_public_key_from_curve25519_public_key(ed25519_public_key_t *pubkey,
- const curve25519_public_key_t *pubkey_in,
- int signbit)
-{
- return get_ed_impl()->pubkey_from_curve25519_pubkey(pubkey->pubkey,
- pubkey_in->public_key,
- signbit);
-}
-
-/**
- * Given an ed25519 keypair in <b>inp</b>, generate a corresponding
- * ed25519 keypair in <b>out</b>, blinded by the corresponding 32-byte input
- * in 'param'.
- *
- * Tor uses key blinding for the "next-generation" hidden services design:
- * service descriptors are encrypted with a key derived from the service's
- * long-term public key, and then signed with (and stored at a position
- * indexed by) a short-term key derived by blinding the long-term keys.
- *
- * Return 0 if blinding was successful, else return -1. */
-int
-ed25519_keypair_blind(ed25519_keypair_t *out,
- const ed25519_keypair_t *inp,
- const uint8_t *param)
-{
- ed25519_public_key_t pubkey_check;
-
- get_ed_impl()->blind_secret_key(out->seckey.seckey,
- inp->seckey.seckey, param);
-
- if (ed25519_public_blind(&pubkey_check, &inp->pubkey, param) < 0) {
- return -1;
- }
- ed25519_public_key_generate(&out->pubkey, &out->seckey);
-
- tor_assert(fast_memeq(pubkey_check.pubkey, out->pubkey.pubkey, 32));
-
- memwipe(&pubkey_check, 0, sizeof(pubkey_check));
-
- return 0;
-}
-
-/**
- * Given an ed25519 public key in <b>inp</b>, generate a corresponding blinded
- * public key in <b>out</b>, blinded with the 32-byte parameter in
- * <b>param</b>. Return 0 on success, -1 on railure.
- */
-int
-ed25519_public_blind(ed25519_public_key_t *out,
- const ed25519_public_key_t *inp,
- const uint8_t *param)
-{
- return get_ed_impl()->blind_public_key(out->pubkey, inp->pubkey, param);
-}
-
-/**
- * Store seckey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
-int
-ed25519_seckey_write_to_file(const ed25519_secret_key_t *seckey,
- const char *filename,
- const char *tag)
-{
- return crypto_write_tagged_contents_to_file(filename,
- "ed25519v1-secret",
- tag,
- seckey->seckey,
- sizeof(seckey->seckey));
-}
-
-/**
- * Read seckey unencrypted from <b>filename</b>, storing it into
- * <b>seckey_out</b>. Set *<b>tag_out</b> to the tag it was marked with.
- * Return 0 on success, -1 on failure.
- */
-int
-ed25519_seckey_read_from_file(ed25519_secret_key_t *seckey_out,
- char **tag_out,
- const char *filename)
-{
- ssize_t len;
-
- len = crypto_read_tagged_contents_from_file(filename, "ed25519v1-secret",
- tag_out, seckey_out->seckey,
- sizeof(seckey_out->seckey));
- if (len == sizeof(seckey_out->seckey)) {
- return 0;
- } else if (len >= 0) {
- errno = EINVAL;
- }
-
- tor_free(*tag_out);
- return -1;
-}
-
-/**
- * Store pubkey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
-int
-ed25519_pubkey_write_to_file(const ed25519_public_key_t *pubkey,
- const char *filename,
- const char *tag)
-{
- return crypto_write_tagged_contents_to_file(filename,
- "ed25519v1-public",
- tag,
- pubkey->pubkey,
- sizeof(pubkey->pubkey));
-}
-
-/**
- * Store pubkey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
-int
-ed25519_pubkey_read_from_file(ed25519_public_key_t *pubkey_out,
- char **tag_out,
- const char *filename)
-{
- ssize_t len;
-
- len = crypto_read_tagged_contents_from_file(filename, "ed25519v1-public",
- tag_out, pubkey_out->pubkey,
- sizeof(pubkey_out->pubkey));
- if (len == sizeof(pubkey_out->pubkey)) {
- return 0;
- } else if (len >= 0) {
- errno = EINVAL;
- }
-
- tor_free(*tag_out);
- return -1;
-}
-
-/** Release all storage held for <b>kp</b>. */
-void
-ed25519_keypair_free_(ed25519_keypair_t *kp)
-{
- if (! kp)
- return;
-
- memwipe(kp, 0, sizeof(*kp));
- tor_free(kp);
-}
-
-/** Return true iff <b>key1</b> and <b>key2</b> are the same public key. */
-int
-ed25519_pubkey_eq(const ed25519_public_key_t *key1,
- const ed25519_public_key_t *key2)
-{
- tor_assert(key1);
- tor_assert(key2);
- return tor_memeq(key1->pubkey, key2->pubkey, ED25519_PUBKEY_LEN);
-}
-
-/**
- * Set <b>dest</b> to contain the same key as <b>src</b>.
- */
-void
-ed25519_pubkey_copy(ed25519_public_key_t *dest,
- const ed25519_public_key_t *src)
-{
- tor_assert(dest);
- tor_assert(src);
- memcpy(dest, src, sizeof(ed25519_public_key_t));
-}
-
-/** Check whether the given Ed25519 implementation seems to be working.
- * If so, return 0; otherwise return -1. */
-MOCK_IMPL(STATIC int,
-ed25519_impl_spot_check,(void))
-{
- static const uint8_t alicesk[32] = {
- 0xc5,0xaa,0x8d,0xf4,0x3f,0x9f,0x83,0x7b,
- 0xed,0xb7,0x44,0x2f,0x31,0xdc,0xb7,0xb1,
- 0x66,0xd3,0x85,0x35,0x07,0x6f,0x09,0x4b,
- 0x85,0xce,0x3a,0x2e,0x0b,0x44,0x58,0xf7
- };
- static const uint8_t alicepk[32] = {
- 0xfc,0x51,0xcd,0x8e,0x62,0x18,0xa1,0xa3,
- 0x8d,0xa4,0x7e,0xd0,0x02,0x30,0xf0,0x58,
- 0x08,0x16,0xed,0x13,0xba,0x33,0x03,0xac,
- 0x5d,0xeb,0x91,0x15,0x48,0x90,0x80,0x25
- };
- static const uint8_t alicemsg[2] = { 0xaf, 0x82 };
- static const uint8_t alicesig[64] = {
- 0x62,0x91,0xd6,0x57,0xde,0xec,0x24,0x02,
- 0x48,0x27,0xe6,0x9c,0x3a,0xbe,0x01,0xa3,
- 0x0c,0xe5,0x48,0xa2,0x84,0x74,0x3a,0x44,
- 0x5e,0x36,0x80,0xd7,0xdb,0x5a,0xc3,0xac,
- 0x18,0xff,0x9b,0x53,0x8d,0x16,0xf2,0x90,
- 0xae,0x67,0xf7,0x60,0x98,0x4d,0xc6,0x59,
- 0x4a,0x7c,0x15,0xe9,0x71,0x6e,0xd2,0x8d,
- 0xc0,0x27,0xbe,0xce,0xea,0x1e,0xc4,0x0a
- };
- const ed25519_impl_t *impl = get_ed_impl();
- uint8_t sk[ED25519_SECKEY_LEN];
- uint8_t pk[ED25519_PUBKEY_LEN];
- uint8_t sig[ED25519_SIG_LEN];
- int r = 0;
-
- /* Some implementations (eg: The modified Ed25519-donna) have handy self-test
- * code that sanity-checks the internals. If present, use that to screen out
- * catastrophic errors like massive compiler failure.
- */
- if (impl->selftest && impl->selftest() != 0)
- goto fail;
-
- /* Validate results versus known answer tests. People really should be
- * running "make test" instead of relying on this, but it's better than
- * nothing.
- *
- * Test vectors taken from "EdDSA & Ed25519 - 6. Test Vectors for Ed25519
- * (TEST3)" (draft-josefsson-eddsa-ed25519-03).
- */
-
- /* Key expansion, public key derivation. */
- if (impl->seckey_expand(sk, alicesk) < 0)
- goto fail;
- if (impl->pubkey(pk, sk) < 0)
- goto fail;
- if (fast_memneq(pk, alicepk, ED25519_PUBKEY_LEN))
- goto fail;
-
- /* Signing, verification. */
- if (impl->sign(sig, alicemsg, sizeof(alicemsg), sk, pk) < 0)
- return -1;
- if (fast_memneq(sig, alicesig, ED25519_SIG_LEN))
- return -1;
- if (impl->open(sig, alicemsg, sizeof(alicemsg), pk) < 0)
- return -1;
-
- /* XXX/yawning: Someone that's more paranoid than I am, can write "Assume
- * ref0 is canonical, and fuzz impl against it" if they want, but I doubt
- * that will catch anything that the known answer tests won't.
- */
- goto end;
-
- // LCOV_EXCL_START -- We can only reach this if our ed25519 implementation is
- // broken.
- fail:
- r = -1;
- // LCOV_EXCL_STOP
- end:
- return r;
-}
-
-/** Force the Ed25519 implementation to a given one, without sanity checking
- * the output. Used for testing.
- */
-void
-ed25519_set_impl_params(int use_donna)
-{
- if (use_donna)
- ed25519_impl = &impl_donna;
- else
- ed25519_impl = &impl_ref10;
-}
-
-/** Choose whether to use the Ed25519-donna implementation. */
-static void
-pick_ed25519_impl(void)
-{
- ed25519_impl = &impl_donna;
-
- if (ed25519_impl_spot_check() == 0)
- return;
-
- /* LCOV_EXCL_START
- * unreachable unless ed25519_donna is broken */
- log_warn(LD_CRYPTO, "The Ed25519-donna implementation seems broken; using "
- "the ref10 implementation.");
- ed25519_impl = &impl_ref10;
- /* LCOV_EXCL_STOP */
-}
-
-/* Initialize the Ed25519 implementation. This is necessary if you're
- * going to use them in a multithreaded setting, and not otherwise. */
-void
-ed25519_init(void)
-{
- pick_ed25519_impl();
-}
-
-/* Return true if <b>point</b> is the identity element of the ed25519 group. */
-static int
-ed25519_point_is_identity_element(const uint8_t *point)
-{
- /* The identity element in ed25159 is the point with coordinates (0,1). */
- static const uint8_t ed25519_identity[32] = {
- 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
- tor_assert(sizeof(ed25519_identity) == ED25519_PUBKEY_LEN);
- return tor_memeq(point, ed25519_identity, sizeof(ed25519_identity));
-}
-
-/** Validate <b>pubkey</b> to ensure that it has no torsion component.
- * Return 0 if <b>pubkey</b> is valid, else return -1. */
-int
-ed25519_validate_pubkey(const ed25519_public_key_t *pubkey)
-{
- uint8_t result[32] = {9};
-
- /* First check that we were not given the identity element */
- if (ed25519_point_is_identity_element(pubkey->pubkey)) {
- log_warn(LD_CRYPTO, "ed25519 pubkey is the identity");
- return -1;
- }
-
- /* For any point on the curve, doing l*point should give the identity element
- * (where l is the group order). Do the computation and check that the
- * identity element is returned. */
- if (get_ed_impl()->ed25519_scalarmult_with_group_order(result,
- pubkey->pubkey) < 0) {
- log_warn(LD_CRYPTO, "ed25519 group order scalarmult failed");
- return -1;
- }
-
- if (!ed25519_point_is_identity_element(result)) {
- log_warn(LD_CRYPTO, "ed25519 validation failed");
- return -1;
- }
-
- return 0;
-}
-