Move key-loading and crosscert-checking out of feature/relay

This is also used by onion services, so it needs to go in another
module.

2 files changed, 810 insertions, 0 deletions

diff --git a/src/feature/keymgt/loadkey.c b/src/feature/keymgt/loadkey.c
new file mode 100644
index 0000000000..4621e39c54
--- /dev/null
+++ b/src/feature/keymgt/loadkey.c
@@ -0,0 +1,755 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file loadkey.c
+ * \brief Read keys from disk, creating as needed
+ *
+ * This code is shared by relays and onion services, which both need
+ * this functionality.
+ **/
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+#include "app/main/main.h"
+#include "feature/keymgt/loadkey.h"
+#include "feature/nodelist/torcert.h"
+
+#include "lib/crypt_ops/crypto_pwbox.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "lib/term/getpass.h"
+#include "lib/crypt_ops/crypto_format.h"
+
+#define ENC_KEY_HEADER "Boxed Ed25519 key"
+#define ENC_KEY_TAG "master"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+/** Try to read an RSA key from <b>fname</b>.  If <b>fname</b> doesn't exist
+ * and <b>generate</b> is true, create a new RSA key and save it in
+ * <b>fname</b>.  Return the read/created key, or NULL on error.  Log all
+ * errors at level <b>severity</b>. If <b>created_out/b> is non-NULL and a
+ * new key was created, set *<b>created_out</b> to true.
+ */
+crypto_pk_t *
+init_key_from_file(const char *fname, int generate, int severity,
+                   bool *created_out)
+{
+  crypto_pk_t *prkey = NULL;
+
+  if (created_out) {
+    *created_out = false;
+  }
+
+  if (!(prkey = crypto_pk_new())) {
+    tor_log(severity, LD_GENERAL,"Error constructing key");
+    goto error;
+  }
+
+  switch (file_status(fname)) {
+    case FN_DIR:
+    case FN_ERROR:
+      tor_log(severity, LD_FS,"Can't read key from \"%s\"", fname);
+      goto error;
+    /* treat empty key files as if the file doesn't exist, and,
+     * if generate is set, replace the empty file in
+     * crypto_pk_write_private_key_to_filename() */
+    case FN_NOENT:
+    case FN_EMPTY:
+      if (generate) {
+        if (!have_lockfile()) {
+          if (try_locking(get_options(), 0)<0) {
+            /* Make sure that --list-fingerprint only creates new keys
+             * if there is no possibility for a deadlock. */
+            tor_log(severity, LD_FS, "Another Tor process has locked \"%s\". "
+                    "Not writing any new keys.", fname);
+            /*XXXX The 'other process' might make a key in a second or two;
+             * maybe we should wait for it. */
+            goto error;
+          }
+        }
+        log_info(LD_GENERAL, "No key found in \"%s\"; generating fresh key.",
+                 fname);
+        if (crypto_pk_generate_key(prkey)) {
+          tor_log(severity, LD_GENERAL,"Error generating onion key");
+          goto error;
+        }
+        if (! crypto_pk_is_valid_private_key(prkey)) {
+          tor_log(severity, LD_GENERAL,"Generated key seems invalid");
+          goto error;
+        }
+        log_info(LD_GENERAL, "Generated key seems valid");
+        if (created_out) {
+          *created_out = true;
+        }
+        if (crypto_pk_write_private_key_to_filename(prkey, fname)) {
+          tor_log(severity, LD_FS,
+              "Couldn't write generated key to \"%s\".", fname);
+          goto error;
+        }
+      } else {
+        tor_log(severity, LD_GENERAL, "No key found in \"%s\"", fname);
+        goto error;
+      }
+      return prkey;
+    case FN_FILE:
+      if (crypto_pk_read_private_key_from_filename(prkey, fname)) {
+        tor_log(severity, LD_GENERAL,"Error loading private key.");
+        goto error;
+      }
+      return prkey;
+    default:
+      tor_assert(0);
+  }
+
+ error:
+  if (prkey)
+    crypto_pk_free(prkey);
+  return NULL;
+}
+
+/* DOCDOC */
+static ssize_t
+do_getpass(const char *prompt, char *buf, size_t buflen,
+           int twice, const or_options_t *options)
+{
+  if (options->keygen_force_passphrase == FORCE_PASSPHRASE_OFF) {
+    tor_assert(buflen);
+    buf[0] = 0;
+    return 0;
+  }
+
+  char *prompt2 = NULL;
+  char *buf2 = NULL;
+  int fd = -1;
+  ssize_t length = -1;
+
+  if (options->use_keygen_passphrase_fd) {
+    twice = 0;
+    fd = options->keygen_passphrase_fd;
+    length = read_all_from_fd(fd, buf, buflen-1);
+    if (length >= 0)
+      buf[length] = 0;
+    goto done_reading;
+  }
+
+  if (twice) {
+    const char msg[] = "One more time:";
+    size_t p2len = strlen(prompt) + 1;
+    if (p2len < sizeof(msg))
+      p2len = sizeof(msg);
+    prompt2 = tor_malloc(p2len);
+    memset(prompt2, ' ', p2len);
+    memcpy(prompt2 + p2len - sizeof(msg), msg, sizeof(msg));
+
+    buf2 = tor_malloc_zero(buflen);
+  }
+
+  while (1) {
+    length = tor_getpass(prompt, buf, buflen);
+    if (length < 0)
+      goto done_reading;
+
+    if (! twice)
+      break;
+
+    ssize_t length2 = tor_getpass(prompt2, buf2, buflen);
+
+    if (length != length2 || tor_memneq(buf, buf2, length)) {
+      fprintf(stderr, "That didn't match.\n");
+    } else {
+      break;
+    }
+  }
+
+ done_reading:
+  if (twice) {
+    tor_free(prompt2);
+    memwipe(buf2, 0, buflen);
+    tor_free(buf2);
+  }
+
+  if (options->keygen_force_passphrase == FORCE_PASSPHRASE_ON && length == 0)
+    return -1;
+
+  return length;
+}
+
+/* DOCDOC */
+int
+read_encrypted_secret_key(ed25519_secret_key_t *out,
+                          const char *fname)
+{
+  int r = -1;
+  uint8_t *secret = NULL;
+  size_t secret_len = 0;
+  char pwbuf[256];
+  uint8_t encrypted_key[256];
+  char *tag = NULL;
+  int saved_errno = 0;
+
+  ssize_t encrypted_len = crypto_read_tagged_contents_from_file(fname,
+                                          ENC_KEY_HEADER,
+                                          &tag,
+                                          encrypted_key,
+                                          sizeof(encrypted_key));
+  if (encrypted_len < 0) {
+    saved_errno = errno;
+    log_info(LD_OR, "%s is missing", fname);
+    r = 0;
+    goto done;
+  }
+  if (strcmp(tag, ENC_KEY_TAG)) {
+    saved_errno = EINVAL;
+    goto done;
+  }
+
+  while (1) {
+    ssize_t pwlen =
+      do_getpass("Enter passphrase for master key:", pwbuf, sizeof(pwbuf), 0,
+                 get_options());
+    if (pwlen < 0) {
+      saved_errno = EINVAL;
+      goto done;
+    }
+    const int r_unbox = crypto_unpwbox(&secret, &secret_len,
+                                       encrypted_key, encrypted_len,
+                                       pwbuf, pwlen);
+    if (r_unbox == UNPWBOX_CORRUPTED) {
+      log_err(LD_OR, "%s is corrupted.", fname);
+      saved_errno = EINVAL;
+      goto done;
+    } else if (r_unbox == UNPWBOX_OKAY) {
+      break;
+    }
+
+    /* Otherwise, passphrase is bad, so try again till user does ctrl-c or gets
+     * it right. */
+  }
+
+  if (secret_len != ED25519_SECKEY_LEN) {
+    log_err(LD_OR, "%s is corrupted.", fname);
+    saved_errno = EINVAL;
+    goto done;
+  }
+  memcpy(out->seckey, secret, ED25519_SECKEY_LEN);
+  r = 1;
+
+ done:
+  memwipe(encrypted_key, 0, sizeof(encrypted_key));
+  memwipe(pwbuf, 0, sizeof(pwbuf));
+  tor_free(tag);
+  if (secret) {
+    memwipe(secret, 0, secret_len);
+    tor_free(secret);
+  }
+  if (saved_errno)
+    errno = saved_errno;
+  return r;
+}
+
+/* DOCDOC */
+int
+write_encrypted_secret_key(const ed25519_secret_key_t *key,
+                           const char *fname)
+{
+  int r = -1;
+  char pwbuf0[256];
+  uint8_t *encrypted_key = NULL;
+  size_t encrypted_len = 0;
+
+  if (do_getpass("Enter new passphrase:", pwbuf0, sizeof(pwbuf0), 1,
+                 get_options()) < 0) {
+    log_warn(LD_OR, "NO/failed passphrase");
+    return -1;
+  }
+
+  if (strlen(pwbuf0) == 0) {
+    if (get_options()->keygen_force_passphrase == FORCE_PASSPHRASE_ON)
+      return -1;
+    else
+      return 0;
+  }
+
+  if (crypto_pwbox(&encrypted_key, &encrypted_len,
+                   key->seckey, sizeof(key->seckey),
+                   pwbuf0, strlen(pwbuf0),  0) < 0) {
+    log_warn(LD_OR, "crypto_pwbox failed!?");
+    goto done;
+  }
+  if (crypto_write_tagged_contents_to_file(fname,
+                                           ENC_KEY_HEADER,
+                                           ENC_KEY_TAG,
+                                           encrypted_key, encrypted_len) < 0)
+    goto done;
+  r = 1;
+ done:
+  if (encrypted_key) {
+    memwipe(encrypted_key, 0, encrypted_len);
+    tor_free(encrypted_key);
+  }
+  memwipe(pwbuf0, 0, sizeof(pwbuf0));
+  return r;
+}
+
+/* DOCDOC */
+static int
+write_secret_key(const ed25519_secret_key_t *key, int encrypted,
+                 const char *fname,
+                 const char *fname_tag,
+                 const char *encrypted_fname)
+{
+  if (encrypted) {
+    int r = write_encrypted_secret_key(key, encrypted_fname);
+    if (r == 1) {
+      /* Success! */
+
+      /* Try to unlink the unencrypted key, if any existed before */
+      if (strcmp(fname, encrypted_fname))
+        unlink(fname);
+      return r;
+    } else if (r != 0) {
+      /* Unrecoverable failure! */
+      return r;
+    }
+
+    fprintf(stderr, "Not encrypting the secret key.\n");
+  }
+  return ed25519_seckey_write_to_file(key, fname, fname_tag);
+}
+
+/**
+ * Read an ed25519 key and associated certificates from files beginning with
+ * <b>fname</b>, with certificate type <b>cert_type</b>.  On failure, return
+ * NULL; on success return the keypair.
+ *
+ * The <b>options</b> is used to look at the change_key_passphrase value when
+ * writing to disk a secret key. It is safe to be NULL even in that case.
+ *
+ * If INIT_ED_KEY_CREATE is set in <b>flags</b>, then create the key (and
+ * certificate if requested) if it doesn't exist, and save it to disk.
+ *
+ * If INIT_ED_KEY_NEEDCERT is set in <b>flags</b>, load/create a certificate
+ * too and store it in *<b>cert_out</b>.  Fail if the cert can't be
+ * found/created.  To create a certificate, <b>signing_key</b> must be set to
+ * the key that should sign it; <b>now</b> to the current time, and
+ * <b>lifetime</b> to the lifetime of the key.
+ *
+ * If INIT_ED_KEY_REPLACE is set in <b>flags</b>, then create and save new key
+ * whether we can read the old one or not.
+ *
+ * If INIT_ED_KEY_EXTRA_STRONG is set in <b>flags</b>, set the extra_strong
+ * flag when creating the secret key.
+ *
+ * If INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT is set in <b>flags</b>, and
+ * we create a new certificate, create it with the signing key embedded.
+ *
+ * If INIT_ED_KEY_SPLIT is set in <b>flags</b>, and we create a new key,
+ * store the public key in a separate file from the secret key.
+ *
+ * If INIT_ED_KEY_MISSING_SECRET_OK is set in <b>flags</b>, and we find a
+ * public key file but no secret key file, return successfully anyway.
+ *
+ * If INIT_ED_KEY_OMIT_SECRET is set in <b>flags</b>, do not try to load a
+ * secret key unless no public key is found.  Do not return a secret key. (but
+ * create and save one if needed).
+ *
+ * If INIT_ED_KEY_TRY_ENCRYPTED is set, we look for an encrypted secret key
+ * and consider encrypting any new secret key.
+ *
+ * If INIT_ED_KEY_NO_REPAIR is set, and there is any issue loading the keys
+ * from disk _other than their absence_ (full or partial), we do not try to
+ * replace them.
+ *
+ * If INIT_ED_KEY_SUGGEST_KEYGEN is set, have log messages about failures
+ * refer to the --keygen option.
+ *
+ * If INIT_ED_KEY_EXPLICIT_FNAME is set, use the provided file name for the
+ * secret key file, encrypted or not.
+ *
+ * If INIT_ED_KEY_OFFLINE_SECRET is set, we won't try to load the master
+ * secret key and we log a message at <b>severity</b> that we've done so.
+ */
+ed25519_keypair_t *
+ed_key_init_from_file(const char *fname, uint32_t flags,
+                      int severity,
+                      const ed25519_keypair_t *signing_key,
+                      time_t now,
+                      time_t lifetime,
+                      uint8_t cert_type,
+                      struct tor_cert_st **cert_out,
+                      const or_options_t *options)
+{
+  char *secret_fname = NULL;
+  char *encrypted_secret_fname = NULL;
+  char *public_fname = NULL;
+  char *cert_fname = NULL;
+  const char *loaded_secret_fname = NULL;
+  int created_pk = 0, created_sk = 0, created_cert = 0;
+  const int try_to_load = ! (flags & INIT_ED_KEY_REPLACE);
+  const int encrypt_key = !! (flags & INIT_ED_KEY_TRY_ENCRYPTED);
+  const int norepair = !! (flags & INIT_ED_KEY_NO_REPAIR);
+  const int split = !! (flags & INIT_ED_KEY_SPLIT);
+  const int omit_secret = !! (flags & INIT_ED_KEY_OMIT_SECRET);
+  const int offline_secret = !! (flags & INIT_ED_KEY_OFFLINE_SECRET);
+  const int explicit_fname = !! (flags & INIT_ED_KEY_EXPLICIT_FNAME);
+
+  /* we don't support setting both of these flags at once. */
+  tor_assert((flags & (INIT_ED_KEY_NO_REPAIR|INIT_ED_KEY_NEEDCERT)) !=
+                      (INIT_ED_KEY_NO_REPAIR|INIT_ED_KEY_NEEDCERT));
+
+  char tag[8];
+  tor_snprintf(tag, sizeof(tag), "type%d", (int)cert_type);
+
+  tor_cert_t *cert = NULL;
+  char *got_tag = NULL;
+  ed25519_keypair_t *keypair = tor_malloc_zero(sizeof(ed25519_keypair_t));
+
+  if (explicit_fname) {
+    secret_fname = tor_strdup(fname);
+    encrypted_secret_fname = tor_strdup(fname);
+  } else {
+    tor_asprintf(&secret_fname, "%s_secret_key", fname);
+    tor_asprintf(&encrypted_secret_fname, "%s_secret_key_encrypted", fname);
+  }
+  tor_asprintf(&public_fname, "%s_public_key", fname);
+  tor_asprintf(&cert_fname, "%s_cert", fname);
+
+  /* Try to read the secret key. */
+  int have_secret = 0;
+  int load_secret = try_to_load &&
+    !offline_secret &&
+    (!omit_secret || file_status(public_fname)==FN_NOENT);
+  if (load_secret) {
+    int rv = ed25519_seckey_read_from_file(&keypair->seckey,
+                                           &got_tag, secret_fname);
+    if (rv == 0) {
+      have_secret = 1;
+      loaded_secret_fname = secret_fname;
+      tor_assert(got_tag);
+    } else {
+      if (errno != ENOENT && norepair) {
+        tor_log(severity, LD_OR, "Unable to read %s: %s", secret_fname,
+                strerror(errno));
+        goto err;
+      }
+    }
+  }
+
+  /* Should we try for an encrypted key? */
+  int have_encrypted_secret_file = 0;
+  if (!have_secret && try_to_load && encrypt_key) {
+    int r = read_encrypted_secret_key(&keypair->seckey,
+                                      encrypted_secret_fname);
+    if (r > 0) {
+      have_secret = 1;
+      have_encrypted_secret_file = 1;
+      tor_free(got_tag); /* convince coverity we aren't leaking */
+      got_tag = tor_strdup(tag);
+      loaded_secret_fname = encrypted_secret_fname;
+    } else if (errno != ENOENT && norepair) {
+      tor_log(severity, LD_OR, "Unable to read %s: %s",
+              encrypted_secret_fname, strerror(errno));
+      goto err;
+    }
+  } else {
+    if (try_to_load) {
+      /* Check if it's there anyway, so we don't replace it. */
+      if (file_status(encrypted_secret_fname) != FN_NOENT)
+        have_encrypted_secret_file = 1;
+    }
+  }
+
+  if (have_secret) {
+    if (strcmp(got_tag, tag)) {
+      tor_log(severity, LD_OR, "%s has wrong tag", loaded_secret_fname);
+      goto err;
+    }
+    /* Derive the public key */
+    if (ed25519_public_key_generate(&keypair->pubkey, &keypair->seckey)<0) {
+      tor_log(severity, LD_OR, "%s can't produce a public key",
+              loaded_secret_fname);
+      goto err;
+    }
+  }
+
+  /* If we do split keys here, try to read the pubkey. */
+  int found_public = 0;
+  if (try_to_load && (!have_secret || split)) {
+    ed25519_public_key_t pubkey_tmp;
+    tor_free(got_tag);
+    found_public = ed25519_pubkey_read_from_file(&pubkey_tmp,
+                                                 &got_tag, public_fname) == 0;
+    if (!found_public && errno != ENOENT && norepair) {
+      tor_log(severity, LD_OR, "Unable to read %s: %s", public_fname,
+              strerror(errno));
+      goto err;
+    }
+    if (found_public && strcmp(got_tag, tag)) {
+      tor_log(severity, LD_OR, "%s has wrong tag", public_fname);
+      goto err;
+    }
+    if (found_public) {
+      if (have_secret) {
+        /* If we have a secret key and we're reloading the public key,
+         * the key must match! */
+        if (! ed25519_pubkey_eq(&keypair->pubkey, &pubkey_tmp)) {
+          tor_log(severity, LD_OR, "%s does not match %s!  If you are trying "
+                  "to restore from backup, make sure you didn't mix up the "
+                  "key files. If you are absolutely sure that %s is the right "
+                  "key for this relay, delete %s or move it out of the way.",
+                  public_fname, loaded_secret_fname,
+                  loaded_secret_fname, public_fname);
+          goto err;
+        }
+      } else {
+        /* We only have the public key; better use that. */
+        tor_assert(split);
+        memcpy(&keypair->pubkey, &pubkey_tmp, sizeof(pubkey_tmp));
+      }
+    } else {
+      /* We have no public key file, but we do have a secret key, make the
+       * public key file! */
+      if (have_secret) {
+        if (ed25519_pubkey_write_to_file(&keypair->pubkey, public_fname, tag)
+            < 0) {
+          tor_log(severity, LD_OR, "Couldn't repair %s", public_fname);
+          goto err;
+        } else {
+          tor_log(LOG_NOTICE, LD_OR,
+                  "Found secret key but not %s. Regenerating.",
+                  public_fname);
+        }
+      }
+    }
+  }
+
+  /* If the secret key is absent and it's not allowed to be, fail. */
+  if (!have_secret && found_public &&
+      !(flags & INIT_ED_KEY_MISSING_SECRET_OK)) {
+    if (have_encrypted_secret_file) {
+      tor_log(severity, LD_OR, "We needed to load a secret key from %s, "
+              "but it was encrypted. Try 'tor --keygen' instead, so you "
+              "can enter the passphrase.",
+              secret_fname);
+    } else if (offline_secret) {
+      tor_log(severity, LD_OR, "We wanted to load a secret key from %s, "
+              "but you're keeping it offline. (OfflineMasterKey is set.)",
+              secret_fname);
+    } else {
+      tor_log(severity, LD_OR, "We needed to load a secret key from %s, "
+              "but couldn't find it. %s", secret_fname,
+              (flags & INIT_ED_KEY_SUGGEST_KEYGEN) ?
+              "If you're keeping your master secret key offline, you will "
+              "need to run 'tor --keygen' to generate new signing keys." :
+              "Did you forget to copy it over when you copied the rest of the "
+              "signing key material?");
+    }
+    goto err;
+  }
+
+  /* If it's absent, and we're not supposed to make a new keypair, fail. */
+  if (!have_secret && !found_public && !(flags & INIT_ED_KEY_CREATE)) {
+    if (split) {
+      tor_log(severity, LD_OR, "No key found in %s or %s.",
+              secret_fname, public_fname);
+    } else {
+      tor_log(severity, LD_OR, "No key found in %s.", secret_fname);
+    }
+    goto err;
+  }
+
+  /* If the secret key is absent, but the encrypted key would be present,
+   * that's an error */
+  if (!have_secret && !found_public && have_encrypted_secret_file) {
+    tor_assert(!encrypt_key);
+    tor_log(severity, LD_OR, "Found an encrypted secret key, "
+            "but not public key file %s!", public_fname);
+    goto err;
+  }
+
+  /* if it's absent, make a new keypair... */
+  if (!have_secret && !found_public) {
+    tor_free(keypair);
+    keypair = ed_key_new(signing_key, flags, now, lifetime,
+                         cert_type, &cert);
+    if (!keypair) {
+      tor_log(severity, LD_OR, "Couldn't create keypair");
+      goto err;
+    }
+    created_pk = created_sk = created_cert = 1;
+  }
+
+  /* Write it to disk if we're supposed to do with a new passphrase, or if
+   * we just created it. */
+  if (created_sk || (have_secret && options != NULL &&
+                     options->change_key_passphrase)) {
+    if (write_secret_key(&keypair->seckey,
+                         encrypt_key,
+                         secret_fname, tag, encrypted_secret_fname) < 0
+        ||
+        (split &&
+         ed25519_pubkey_write_to_file(&keypair->pubkey, public_fname, tag) < 0)
+        ||
+        (cert &&
+         crypto_write_tagged_contents_to_file(cert_fname, "ed25519v1-cert",
+                                 tag, cert->encoded, cert->encoded_len) < 0)) {
+      tor_log(severity, LD_OR, "Couldn't write keys or cert to file.");
+      goto err;
+    }
+    goto done;
+  }
+
+  /* If we're not supposed to get a cert, we're done. */
+  if (! (flags & INIT_ED_KEY_NEEDCERT))
+    goto done;
+
+  /* Read a cert. */
+  tor_free(got_tag);
+  uint8_t certbuf[256];
+  ssize_t cert_body_len = crypto_read_tagged_contents_from_file(
+                 cert_fname, "ed25519v1-cert",
+                 &got_tag, certbuf, sizeof(certbuf));
+  if (cert_body_len >= 0 && !strcmp(got_tag, tag))
+    cert = tor_cert_parse(certbuf, cert_body_len);
+
+  /* If we got it, check it to the extent we can. */
+  int bad_cert = 0;
+
+  if (! cert) {
+    tor_log(severity, LD_OR, "Cert was unparseable");
+    bad_cert = 1;
+  } else if (!tor_memeq(cert->signed_key.pubkey, keypair->pubkey.pubkey,
+                        ED25519_PUBKEY_LEN)) {
+    tor_log(severity, LD_OR, "Cert was for wrong key");
+    bad_cert = 1;
+  } else if (signing_key &&
+             tor_cert_checksig(cert, &signing_key->pubkey, now) < 0) {
+    tor_log(severity, LD_OR, "Can't check certificate: %s",
+            tor_cert_describe_signature_status(cert));
+    bad_cert = 1;
+  } else if (cert->cert_expired) {
+    tor_log(severity, LD_OR, "Certificate is expired");
+    bad_cert = 1;
+  } else if (signing_key && cert->signing_key_included &&
+             ! ed25519_pubkey_eq(&signing_key->pubkey, &cert->signing_key)) {
+    tor_log(severity, LD_OR, "Certificate signed by unexpectd key!");
+    bad_cert = 1;
+  }
+
+  if (bad_cert) {
+    tor_cert_free(cert);
+    cert = NULL;
+  }
+
+  /* If we got a cert, we're done. */
+  if (cert)
+    goto done;
+
+  /* If we didn't get a cert, and we're not supposed to make one, fail. */
+  if (!signing_key || !(flags & INIT_ED_KEY_CREATE)) {
+    tor_log(severity, LD_OR, "Without signing key, can't create certificate");
+    goto err;
+  }
+
+  /* We have keys but not a certificate, so make one. */
+  uint32_t cert_flags = 0;
+  if (flags & INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT)
+    cert_flags |= CERT_FLAG_INCLUDE_SIGNING_KEY;
+  cert = tor_cert_create(signing_key, cert_type,
+                         &keypair->pubkey,
+                         now, lifetime,
+                         cert_flags);
+
+  if (! cert) {
+    tor_log(severity, LD_OR, "Couldn't create certificate");
+    goto err;
+  }
+
+  /* Write it to disk. */
+  created_cert = 1;
+  if (crypto_write_tagged_contents_to_file(cert_fname, "ed25519v1-cert",
+                             tag, cert->encoded, cert->encoded_len) < 0) {
+    tor_log(severity, LD_OR, "Couldn't write cert to disk.");
+    goto err;
+  }
+
+ done:
+  if (cert_out)
+    *cert_out = cert;
+  else
+    tor_cert_free(cert);
+
+  goto cleanup;
+
+ err:
+  if (keypair)
+    memwipe(keypair, 0, sizeof(*keypair));
+  tor_free(keypair);
+  tor_cert_free(cert);
+  if (cert_out)
+    *cert_out = NULL;
+  if (created_sk)
+    unlink(secret_fname);
+  if (created_pk)
+    unlink(public_fname);
+  if (created_cert)
+    unlink(cert_fname);
+
+ cleanup:
+  tor_free(encrypted_secret_fname);
+  tor_free(secret_fname);
+  tor_free(public_fname);
+  tor_free(cert_fname);
+  tor_free(got_tag);
+
+  return keypair;
+}
+
+/**
+ * Create a new signing key and (optionally) certficiate; do not read or write
+ * from disk.  See ed_key_init_from_file() for more information.
+ */
+ed25519_keypair_t *
+ed_key_new(const ed25519_keypair_t *signing_key,
+           uint32_t flags,
+           time_t now,
+           time_t lifetime,
+           uint8_t cert_type,
+           struct tor_cert_st **cert_out)
+{
+  if (cert_out)
+    *cert_out = NULL;
+
+  const int extra_strong = !! (flags & INIT_ED_KEY_EXTRA_STRONG);
+  ed25519_keypair_t *keypair = tor_malloc_zero(sizeof(ed25519_keypair_t));
+  if (ed25519_keypair_generate(keypair, extra_strong) < 0)
+    goto err;
+
+  if (! (flags & INIT_ED_KEY_NEEDCERT))
+    return keypair;
+
+  tor_assert(signing_key);
+  tor_assert(cert_out);
+  uint32_t cert_flags = 0;
+  if (flags & INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT)
+    cert_flags |= CERT_FLAG_INCLUDE_SIGNING_KEY;
+  tor_cert_t *cert = tor_cert_create(signing_key, cert_type,
+                                     &keypair->pubkey,
+                                     now, lifetime,
+                                     cert_flags);
+  if (! cert)
+    goto err;
+
+  *cert_out = cert;
+  return keypair;
+
+ err:
+  tor_free(keypair);
+  return NULL;
+}
diff --git a/src/feature/keymgt/loadkey.h b/src/feature/keymgt/loadkey.h
new file mode 100644
index 0000000000..7717bda29e
--- /dev/null
+++ b/src/feature/keymgt/loadkey.h
@@ -0,0 +1,55 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file loadkey.h
+ * \brief Header file for loadkey.c
+ **/
+
+#ifndef TOR_LOADKEY_H
+#define TOR_LOADKEY_H
+
+#include "lib/crypt_ops/crypto_ed25519.h"
+
+crypto_pk_t *init_key_from_file(const char *fname, int generate,
+                                int severity, bool *created_out);
+
+#define INIT_ED_KEY_CREATE                      (1u<<0)
+#define INIT_ED_KEY_REPLACE                     (1u<<1)
+#define INIT_ED_KEY_SPLIT                       (1u<<2)
+#define INIT_ED_KEY_MISSING_SECRET_OK           (1u<<3)
+#define INIT_ED_KEY_NEEDCERT                    (1u<<4)
+#define INIT_ED_KEY_EXTRA_STRONG                (1u<<5)
+#define INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT (1u<<6)
+#define INIT_ED_KEY_OMIT_SECRET                 (1u<<7)
+#define INIT_ED_KEY_TRY_ENCRYPTED               (1u<<8)
+#define INIT_ED_KEY_NO_REPAIR                   (1u<<9)
+#define INIT_ED_KEY_SUGGEST_KEYGEN              (1u<<10)
+#define INIT_ED_KEY_OFFLINE_SECRET              (1u<<11)
+#define INIT_ED_KEY_EXPLICIT_FNAME              (1u<<12)
+
+struct tor_cert_st;
+ed25519_keypair_t *ed_key_init_from_file(const char *fname, uint32_t flags,
+                                         int severity,
+                                         const ed25519_keypair_t *signing_key,
+                                         time_t now,
+                                         time_t lifetime,
+                                         uint8_t cert_type,
+                                         struct tor_cert_st **cert_out,
+                                         const or_options_t *options);
+ed25519_keypair_t *ed_key_new(const ed25519_keypair_t *signing_key,
+                              uint32_t flags,
+                              time_t now,
+                              time_t lifetime,
+                              uint8_t cert_type,
+                              struct tor_cert_st **cert_out);
+
+int read_encrypted_secret_key(ed25519_secret_key_t *out,
+                              const char *fname);
+int write_encrypted_secret_key(const ed25519_secret_key_t *out,
+                               const char *fname);
+
+#endif