Add Ed25519 support, wrappers, and tests.

Taken from earlier ed25519 branch based on floodyberry's
ed25519-donna.  Tweaked so that it applies to ref10 instead.

.gitignore

@@ -134,6 +134,10 @@
 /src/config/torrc
 /src/config/torrc.sample
 
+# /src/ext/
+/src/ext/ed25519/ref10/libed25519_ref10.a
+/src/ext/ed25519/ref10/libed25519_ref10.lib
+
 # /src/or/
 /src/or/Makefile
 /src/or/Makefile.in

src/common/crypto_curve25519.c

@@ -63,26 +63,44 @@ curve25519_public_key_is_ok(const curve25519_public_key_t *key)
   return !safe_mem_is_zero(key->public_key, CURVE25519_PUBKEY_LEN);
 }
 
-/** Generate a new keypair and return the secret key.  If <b>extra_strong</b>
- * is true, this key is possibly going to get used more than once, so
- * use a better-than-usual RNG. Return 0 on success, -1 on failure. */
+/**
+ * Generate CURVE25519_SECKEY_LEN random bytes in <b>out</b>. If
+ * <b>extra_strong</b> is true, this key is possibly going to get used more
+ * than once, so use a better-than-usual RNG. Return 0 on success, -1 on
+ * failure.
+ *
+ * This function does not adjust the output of the RNG at all; the will caller
+ * will need to clear or set the appropriate bits to make curve25519 work.
+ */
 int
-curve25519_secret_key_generate(curve25519_secret_key_t *key_out,
-                               int extra_strong)
+curve25519_rand_seckey_bytes(uint8_t *out, int extra_strong)
 {
   uint8_t k_tmp[CURVE25519_SECKEY_LEN];
 
-  if (crypto_rand((char*)key_out->secret_key, CURVE25519_SECKEY_LEN) < 0)
+  if (crypto_rand((char*)out, CURVE25519_SECKEY_LEN) < 0)
     return -1;
   if (extra_strong && !crypto_strongest_rand(k_tmp, CURVE25519_SECKEY_LEN)) {
     /* If they asked for extra-strong entropy and we have some, use it as an
      * HMAC key to improve not-so-good entropy rather than using it directly,
      * just in case the extra-strong entropy is less amazing than we hoped. */
-    crypto_hmac_sha256((char *)key_out->secret_key,
-                    (const char *)k_tmp, sizeof(k_tmp),
-                    (const char *)key_out->secret_key, CURVE25519_SECKEY_LEN);
+    crypto_hmac_sha256((char*) out,
+                       (const char *)k_tmp, sizeof(k_tmp),
+                       (const char *)out, CURVE25519_SECKEY_LEN);
   }
   memwipe(k_tmp, 0, sizeof(k_tmp));
+  return 0;
+}
+
+/** Generate a new keypair and return the secret key.  If <b>extra_strong</b>
+ * is true, this key is possibly going to get used more than once, so
+ * use a better-than-usual RNG. Return 0 on success, -1 on failure. */
+int
+curve25519_secret_key_generate(curve25519_secret_key_t *key_out,
+                               int extra_strong)
+{
+  if (curve25519_rand_seckey_bytes(key_out->secret_key, extra_strong) < 0)
+    return -1;
+
   key_out->secret_key[0] &= 248;
   key_out->secret_key[31] &= 127;
   key_out->secret_key[31] |= 64;

src/common/crypto_curve25519.h

@@ -57,6 +57,8 @@ int curve25519_keypair_read_from_file(curve25519_keypair_t *keypair_out,
                                       char **tag_out,
                                       const char *fname);
 
+int curve25519_rand_seckey_bytes(uint8_t *out, int extra_strong);
+
 #ifdef CRYPTO_CURVE25519_PRIVATE
 STATIC int curve25519_impl(uint8_t *output, const uint8_t *secret,
                            const uint8_t *basepoint);

src/common/crypto_ed25519.c

+/* Copyright (c) 2013, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/* Wrapper code for an ed25519 implementation. */
+
+#include "orconfig.h"
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
+#include "crypto.h"
+
+#include "crypto_curve25519.h"
+#include "crypto_ed25519.h"
+#include "torlog.h"
+#include "util.h"
+
+#include "ed25519/ref10/ed25519_ref10.h"
+
+int
+ed25519_secret_key_generate(ed25519_secret_key_t *seckey_out,
+                        int extra_strong)
+{
+  (void) extra_strong;
+  if (ed25519_ref10_seckey(seckey_out->seckey) < 0)
+    return -1;
+  return 0;
+}
+
+int
+ed25519_public_key_generate(ed25519_public_key_t *pubkey_out,
+                        const ed25519_secret_key_t *seckey)
+{
+  if (ed25519_ref10_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)
+{
+  (void) extra_strong;
+
+  if (ed25519_ref10_keygen(keypair_out->pubkey.pubkey,
+                           keypair_out->seckey.seckey)<0)
+    return -1;
+  return 0;
+}
+
+/**
+ * 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>.
+ */
+int
+ed25519_sign(ed25519_signature_t *signature_out,
+             const uint8_t *msg, size_t len,
+             const ed25519_keypair_t *keypair)
+{
+  uint8_t keys[64];
+  uint8_t *tmp;
+  uint64_t tmplen;
+
+  /* XXXX Make crypto_sign in ref10 friendlier so we don't need this stupid
+   * copying. */
+  tor_assert(len < SIZE_T_CEILING - 64);
+  tmplen = ((uint64_t)len) + 64;
+  tmp = tor_malloc(tmplen);
+
+  memcpy(keys, keypair->seckey.seckey, 32);
+  memcpy(keys+32, keypair->pubkey.pubkey, 32);
+
+  if (ed25519_ref10_sign(tmp, &tmplen, msg, len, keys) < 0) {
+    tor_free(tmp);
+    return -1;
+  }
+
+  memcpy(signature_out->sig, tmp, 64);
+  memwipe(keys, 0, sizeof(keys));
+
+  tor_free(tmp);
+
+  return 0;
+}
+
+/**
+ * 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.
+ */
+int
+ed25519_checksig(const ed25519_signature_t *signature,
+                 const uint8_t *msg, size_t len,
+                 const ed25519_public_key_t *pubkey)
+{
+  uint8_t *smtmp;
+  uint8_t *tmp;
+  uint64_t tmplen;
+  int r;
+
+  tor_assert(len < SIZE_T_CEILING - 64);
+  tmplen = len + 64;
+  tmp = tor_malloc(tmplen);
+  smtmp = tor_malloc(tmplen);
+  memcpy(smtmp, signature->sig, 64);
+  memcpy(smtmp+64, msg, len);
+
+  r = ed25519_ref10_open(tmp, &tmplen, smtmp, tmplen, pubkey->pubkey);
+
+  tor_free(tmp);
+  tor_free(smtmp);
+
+  return r;
+}
+
+/** 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.
+ */
+int
+ed25519_checksig_batch(int *okay_out,
+                       const ed25519_checkable_t *checkable,
+                       int n_checkable)
+{
+  int res, i;
+
+  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);
+  }
+
+#if 0
+  const uint8_t **ms;
+  size_t *lens;
+  const uint8_t **pks;
+  const uint8_t **sigs;
+  int *oks;
+
+  ms = tor_malloc(sizeof(uint8_t*)*n_checkable);
+  lens = tor_malloc(sizeof(size_t)*n_checkable);
+  pks = tor_malloc(sizeof(uint8_t*)*n_checkable);
+  sigs = tor_malloc(sizeof(uint8_t*)*n_checkable);
+  oks = okay_out ? okay_out : tor_malloc(sizeof(int)*n_checkable);
+
+  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;
+  }
+
+  ed25519_sign_open_batch_donna_fb(ms, lens, pks, sigs, n_checkable, oks);
+
+  res = 0;
+  for (i = 0; i < n_checkable; ++i) {
+    if (!oks[i])
+      --res;
+  }
+
+  tor_free(ms);
+  tor_free(lens);
+  tor_free(pks);
+  if (! okay_out)
+    tor_free(oks);
+#endif
+
+  return res;
+}
+

src/common/crypto_ed25519.h

+/* Copyright (c) 2012-2013, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_CRYPTO_ED25519_H
+#define TOR_CRYPTO_ED25519_H
+
+#include "testsupport.h"
+#include "torint.h"
+
+#define ED25519_PUBKEY_LEN 32
+#define ED25519_SECKEY_LEN 32
+#define ED25519_SIG_LEN 64
+
+/** An Ed25519 signature. */
+typedef struct {
+  uint8_t sig[ED25519_SIG_LEN];
+} ed25519_signature_t;
+
+/** An Ed25519 public key */
+typedef struct {
+  uint8_t pubkey[ED25519_PUBKEY_LEN];
+} ed25519_public_key_t;
+
+/** An Ed25519 secret key */
+typedef struct {
+  uint8_t seckey[ED25519_SECKEY_LEN];
+} ed25519_secret_key_t;
+
+/** An Ed25519 keypair. */
+typedef struct {
+  ed25519_public_key_t pubkey;
+  ed25519_secret_key_t seckey;
+} ed25519_keypair_t;
+
+#ifdef CURVE25519_ENABLED
+int ed25519_secret_key_generate(ed25519_secret_key_t *seckey_out,
+                            int extra_strong);
+int ed25519_public_key_generate(ed25519_public_key_t *pubkey_out,
+                            const ed25519_secret_key_t *seckey);
+int ed25519_keypair_generate(ed25519_keypair_t *keypair_out, int extra_strong);
+int ed25519_sign(ed25519_signature_t *signature_out,
+                 const uint8_t *msg, size_t len,
+                 const ed25519_keypair_t *key);
+int ed25519_checksig(const ed25519_signature_t *signature,
+                     const uint8_t *msg, size_t len,
+                     const ed25519_public_key_t *pubkey);
+
+/**
+ * A collection of information necessary to check an Ed25519 signature. Used
+ * for batch verification.
+ */
+typedef struct {
+  /** The public key that supposedly generated the signature. */
+  ed25519_public_key_t *pubkey;
+  /** The signature to check. */
+  ed25519_signature_t signature;
+  /** The message that the signature is supposed to have been applied to. */
+  const uint8_t *msg;
+  /** The length of the message. */
+  size_t len;
+} ed25519_checkable_t;
+
+int ed25519_checksig_batch(int *okay_out,
+                           const ed25519_checkable_t *checkable,
+                           int n_checkable);
+#endif
+
+/* XXXX write secret keys to disk, load secret keys from disk, read encrypted,
+ * write encrypted. serialize public. parse public. */
+
+#endif
+

src/common/include.am

@@ -52,8 +52,12 @@ LIBDONNA=
 endif
 endif
 
+LIBDONNA += $(LIBED25519_REF10)
+
 if CURVE25519_ENABLED
-libcrypto_extra_source=src/common/crypto_curve25519.c
+libcrypto_extra_source = \
+	src/common/crypto_curve25519.c \
+	src/common/crypto_ed25519.c
 endif
 
 LIBOR_A_SOURCES = \
@@ -110,6 +114,7 @@ COMMONHEADERS = \
   src/common/container.h			\
   src/common/crypto.h				\
   src/common/crypto_curve25519.h		\
+  src/common/crypto_ed25519.h			\
   src/common/di_ops.h				\
   src/common/memarea.h				\
   src/common/linux_syscalls.inc			\

src/ext/include.am

@@ -77,5 +77,7 @@ ED25519_REF10_HDRS = \
 	src/ext/ed25519/ref10/sqrtm1.h
 
 noinst_HEADERS += $(ED25519_REF10_HDRS)
-noinst_LIBRARIES += src/ext/ed25519/ref10/libed25519_ref10.a
+
+LIBED25519_REF10=src/ext/ed25519/ref10/libed25519_ref10.a
+noinst_LIBRARIES += $(LIBED25519_REF10)
 

src/test/test_crypto.c

@@ -12,6 +12,7 @@
 #include "siphash.h"
 #ifdef CURVE25519_ENABLED
 #include "crypto_curve25519.h"
+#include "crypto_ed25519.h"
 #endif
 
 extern const char AUTHORITY_SIGNKEY_3[];
@@ -1161,6 +1162,188 @@ test_crypto_curve25519_persist(void *arg)
   tor_free(tag);
 }
 
+static void
+test_crypto_ed25519_simple(void *arg)
+{
+  ed25519_keypair_t kp1, kp2;
+  ed25519_public_key_t pub1, pub2;
+  ed25519_secret_key_t sec1, sec2;
+  ed25519_signature_t sig1, sig2;
+  const uint8_t msg[] =
+    "GNU will be able to run Unix programs, "
+    "but will not be identical to Unix.";
+  const uint8_t msg2[] =
+    "Microsoft Windows extends the features of the DOS operating system, "
+    "yet is compatible with most existing applications that run under DOS.";
+  size_t msg_len = strlen((const char*)msg);
+  size_t msg2_len = strlen((const char*)msg2);
+
+  (void)arg;
+
+  tt_int_op(0, ==, ed25519_secret_key_generate(&sec1, 0));
+  tt_int_op(0, ==, ed25519_secret_key_generate(&sec2, 1));
+
+  tt_int_op(0, ==, ed25519_public_key_generate(&pub1, &sec1));
+  tt_int_op(0, ==, ed25519_public_key_generate(&pub2, &sec1));
+
+  test_memeq(pub1.pubkey, pub2.pubkey, sizeof(pub1.pubkey));
+
+  memcpy(&kp1.pubkey, &pub1, sizeof(pub1));
+  memcpy(&kp1.seckey, &sec1, sizeof(sec1));
+  tt_int_op(0, ==, ed25519_sign(&sig1, msg, msg_len, &kp1));
+  tt_int_op(0, ==, ed25519_sign(&sig2, msg, msg_len, &kp1));
+
+  /* Ed25519 signatures are deterministic */
+  test_memeq(sig1.sig, sig2.sig, sizeof(sig1.sig));
+
+  /* Basic signature is valid. */
+  tt_int_op(0, ==, ed25519_checksig(&sig1, msg, msg_len, &pub1));
+
+  /* Altered signature doesn't work. */
+  sig1.sig[0] ^= 3;
+  tt_int_op(-1, ==, ed25519_checksig(&sig1, msg, msg_len, &pub1));
+
+  /* Wrong public key doesn't work. */
+  tt_int_op(0, ==, ed25519_public_key_generate(&pub2, &sec2));
+  tt_int_op(-1, ==, ed25519_checksig(&sig2, msg, msg_len, &pub2));
+
+  /* Wrong message doesn't work. */
+  tt_int_op(0, ==, ed25519_checksig(&sig2, msg, msg_len, &pub1));
+  tt_int_op(-1, ==, ed25519_checksig(&sig2, msg, msg_len-1, &pub1));
+  tt_int_op(-1, ==, ed25519_checksig(&sig2, msg2, msg2_len, &pub1));
+
+  /* Batch signature checking works with some bad. */
+  tt_int_op(0, ==, ed25519_keypair_generate(&kp2, 0));
+  tt_int_op(0, ==, ed25519_sign(&sig1, msg, msg_len, &kp2));
+  {
+    ed25519_checkable_t ch[] = {
+      { &pub1, sig2, msg, msg_len }, /*ok*/
+      { &pub1, sig2, msg, msg_len-1 }, /*bad*/
+      { &kp2.pubkey, sig2, msg2, msg2_len }, /*bad*/
+      { &kp2.pubkey, sig1, msg, msg_len }, /*ok*/
+    };
+    int okay[4];
+    tt_int_op(-2, ==, ed25519_checksig_batch(okay, ch, 4));
+    tt_int_op(okay[0], ==, 1);
+    tt_int_op(okay[1], ==, 0);
+    tt_int_op(okay[2], ==, 0);
+    tt_int_op(okay[3], ==, 1);
+    tt_int_op(-2, ==, ed25519_checksig_batch(NULL, ch, 4));
+  }
+
+  /* Batch signature checking works with all good. */
+  {
+    ed25519_checkable_t ch[] = {
+      { &pub1, sig2, msg, msg_len }, /*ok*/
+      { &kp2.pubkey, sig1, msg, msg_len }, /*ok*/
+    };
+    int okay[2];
+    tt_int_op(0, ==, ed25519_checksig_batch(okay, ch, 2));
+    tt_int_op(okay[0], ==, 1);
+    tt_int_op(okay[1], ==, 1);
+    tt_int_op(0, ==, ed25519_checksig_batch(NULL, ch, 2));
+  }
+
+ done:
+  ;
+}
+
+static void
+test_crypto_ed25519_test_vectors(void *arg)
+{
+  char *mem_op_hex_tmp=NULL;
+  int i;
+  struct {
+    const char *sk;
+    const char *pk;
+    const char *sig;
+    const char *msg;
+  } items[] = {
+    /* These test vectors were generated with the "ref" implementation of
+     * ed25519 from SUPERCOP-20130419 */
+    { "4c6574277320686f706520746865726520617265206e6f206275677320696e20",
+      "f3e0e493b30f56e501aeb868fc912fe0c8b76621efca47a78f6d75875193dd87",
+      "b5d7fd6fd3adf643647ce1fe87a2931dedd1a4e38e6c662bedd35cdd80bfac51"
+        "1b2c7d1ee6bd929ac213014e1a8dc5373854c7b25dbe15ec96bf6c94196fae06",
+      "506c6561736520657863757365206d7920667269656e642e2048652069736e2774"
+      "204e554c2d7465726d696e617465642e"
+    },
+
+    { "74686520696d706c656d656e746174696f6e20776869636820617265206e6f74",
+      "407f0025a1e1351a4cb68e92f5c0ebaf66e7aaf93a4006a4d1a66e3ede1cfeac",
+      "02884fde1c3c5944d0ecf2d133726fc820c303aae695adceabf3a1e01e95bf28"
+        "da88c0966f5265e9c6f8edc77b3b96b5c91baec3ca993ccd21a3f64203600601",
+      "506c6561736520657863757365206d7920667269656e642e2048652069736e2774"
+      "204e554c2d7465726d696e617465642e"
+    },
+    { "6578706f73656420627920456e676c697368207465787420617320696e707574",
+      "61681cb5fbd69f9bc5a462a21a7ab319011237b940bc781cdc47fcbe327e7706",
+      "6a127d0414de7510125d4bc214994ffb9b8857a46330832d05d1355e882344ad"
+        "f4137e3ca1f13eb9cc75c887ef2309b98c57528b4acd9f6376c6898889603209",
+      "506c6561736520657863757365206d7920667269656e642e2048652069736e2774"
+      "204e554c2d7465726d696e617465642e"
+    },
+
+    /* These come from "sign.input" in ed25519's page */
+    { "5b5a619f8ce1c66d7ce26e5a2ae7b0c04febcd346d286c929e19d0d5973bfef9",
+      "6fe83693d011d111131c4f3fbaaa40a9d3d76b30012ff73bb0e39ec27ab18257",
+      "0f9ad9793033a2fa06614b277d37381e6d94f65ac2a5a94558d09ed6ce922258"
+        "c1a567952e863ac94297aec3c0d0c8ddf71084e504860bb6ba27449b55adc40e",
+      "5a8d9d0a22357e6655f9c785"
+    },
+    { "940c89fe40a81dafbdb2416d14ae469119869744410c3303bfaa0241dac57800",
+      "a2eb8c0501e30bae0cf842d2bde8dec7386f6b7fc3981b8c57c9792bb94cf2dd",
+      "d8bb64aad8c9955a115a793addd24f7f2b077648714f49c4694ec995b330d09d"
+        "640df310f447fd7b6cb5c14f9fe9f490bcf8cfadbfd2169c8ac20d3b8af49a0c",
+      "b87d3813e03f58cf19fd0b6395"
+    },
+    { "9acad959d216212d789a119252ebfe0c96512a23c73bd9f3b202292d6916a738",
+      "cf3af898467a5b7a52d33d53bc037e2642a8da996903fc252217e9c033e2f291",
+      "6ee3fe81e23c60eb2312b2006b3b25e6838e02106623f844c44edb8dafd66ab0"
+        "671087fd195df5b8f58a1d6e52af42908053d55c7321010092748795ef94cf06",
+      "55c7fa434f5ed8cdec2b7aeac173",
+    },
+    { "d5aeee41eeb0e9d1bf8337f939587ebe296161e6bf5209f591ec939e1440c300",
+      "fd2a565723163e29f53c9de3d5e8fbe36a7ab66e1439ec4eae9c0a604af291a5",
+      "f68d04847e5b249737899c014d31c805c5007a62c0a10d50bb1538c5f3550395"
+        "1fbc1e08682f2cc0c92efe8f4985dec61dcbd54d4b94a22547d24451271c8b00",
+      "0a688e79be24f866286d4646b5d81c"
+    },
+
+    { NULL, NULL, NULL, NULL}
+  };
+
+  (void)arg;
+
+  for (i = 0; items[i].pk; ++i) {
+    ed25519_keypair_t kp;
+    ed25519_signature_t sig;
+    uint8_t *msg;
+    size_t msg_len;
+    base16_decode((char*)kp.seckey.seckey, sizeof(kp.seckey.seckey),
+                  items[i].sk, 64);
+    tt_int_op(0, ==, ed25519_public_key_generate(&kp.pubkey, &kp.seckey));
+    test_memeq_hex(kp.pubkey.pubkey, items[i].pk);
+
+    msg_len = strlen(items[i].msg) / 2;
+    msg = tor_malloc(msg_len);
+    base16_decode((char*)msg, msg_len, items[i].msg, strlen(items[i].msg));
+
+    tt_int_op(0, ==, ed25519_sign(&sig, msg, msg_len, &kp));
+    test_memeq_hex(sig.sig, items[i].sig);
+
+    tor_free(msg);
+  }
+
+ done:
+  tor_free(mem_op_hex_tmp);
+}
+
+/* XXX
+     Check known values for secret->public, for public,msg->signature.
+ */
+
+
 #endif
 
 static void
@@ -1300,6 +1483,8 @@ struct testcase_t crypto_tests[] = {
   { "curve25519_wrappers", test_crypto_curve25519_wrappers, 0, NULL, NULL },
   { "curve25519_encode", test_crypto_curve25519_encode, 0, NULL, NULL },
   { "curve25519_persist", test_crypto_curve25519_persist, 0, NULL, NULL },
+  { "ed25519_simple", test_crypto_ed25519_simple, 0, NULL, NULL },
+  { "ed25519_test_vectors", test_crypto_ed25519_test_vectors, 0, NULL, NULL },
 #endif
   { "siphash", test_crypto_siphash, 0, NULL, NULL },
   END_OF_TESTCASES