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.

1 files changed, 181 insertions, 0 deletions

diff --git a/src/common/crypto_ed25519.c b/src/common/crypto_ed25519.c
new file mode 100644
index 0000000000..c39f4f4fe2
--- /dev/null
+++ b/src/common/crypto_ed25519.c
@@ -0,0 +1,181 @@
+/* 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;
+}
+