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author | Nick Mathewson <nickm@torproject.org> | 2018-06-21 12:46:11 -0400 |
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committer | Nick Mathewson <nickm@torproject.org> | 2018-06-21 13:14:14 -0400 |
commit | 25ccfff86a5b29c9c1ec9b3d01fe1dc796e9afa0 (patch) | |
tree | 1c23ec9dd2cea5d00e4262fa4574ffdb9e250aa7 /src/common/crypto_ed25519.c | |
parent | 49d7c9ce53daa13daae59eedceb07d28e06e4395 (diff) | |
download | tor-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')
-rw-r--r-- | src/common/crypto_ed25519.c | 817 |
1 files changed, 0 insertions, 817 deletions
diff --git a/src/common/crypto_ed25519.c b/src/common/crypto_ed25519.c deleted file mode 100644 index b0b954796c..0000000000 --- a/src/common/crypto_ed25519.c +++ /dev/null @@ -1,817 +0,0 @@ -/* 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; -} - |