1 files changed, 110 insertions, 0 deletions
diff --git a/src/crypto/evp/p_x25519.c b/src/crypto/evp/p_x25519.c
new file mode 100644
index 00000000..ed7df39a
--- /dev/null
+++ b/src/crypto/evp/p_x25519.c
@@ -0,0 +1,110 @@
+/* Copyright (c) 2019, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/evp.h>
+
+#include <openssl/curve25519.h>
+#include <openssl/err.h>
+#include <openssl/mem.h>
+
+#include "internal.h"
+
+
+// X25519 has no parameters to copy.
+static int pkey_x25519_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) { return 1; }
+
+static int pkey_x25519_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
+  X25519_KEY *key = OPENSSL_malloc(sizeof(X25519_KEY));
+  if (key == NULL) {
+    OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
+    return 0;
+  }
+
+  if (!EVP_PKEY_set_type(pkey, EVP_PKEY_X25519)) {
+    OPENSSL_free(key);
+    return 0;
+  }
+
+  X25519_keypair(key->pub, key->priv);
+  key->has_private = 1;
+
+  OPENSSL_free(pkey->pkey.ptr);
+  pkey->pkey.ptr = key;
+  return 1;
+}
+
+static int pkey_x25519_derive(EVP_PKEY_CTX *ctx, uint8_t *out,
+                              size_t *out_len) {
+  if (ctx->pkey == NULL || ctx->peerkey == NULL) {
+    OPENSSL_PUT_ERROR(EVP, EVP_R_KEYS_NOT_SET);
+    return 0;
+  }
+
+  const X25519_KEY *our_key = ctx->pkey->pkey.ptr;
+  const X25519_KEY *peer_key = ctx->peerkey->pkey.ptr;
+  if (our_key == NULL || peer_key == NULL) {
+    OPENSSL_PUT_ERROR(EVP, EVP_R_KEYS_NOT_SET);
+    return 0;
+  }
+
+  if (!our_key->has_private) {
+    OPENSSL_PUT_ERROR(EVP, EVP_R_NOT_A_PRIVATE_KEY);
+    return 0;
+  }
+
+  if (out != NULL) {
+    if (*out_len < 32) {
+      OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
+      return 0;
+    }
+    if (!X25519(out, our_key->priv, peer_key->pub)) {
+      OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PEER_KEY);
+      return 0;
+    }
+  }
+
+  *out_len = 32;
+  return 1;
+}
+
+static int pkey_x25519_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) {
+  switch (type) {
+    case EVP_PKEY_CTRL_PEER_KEY:
+      // |EVP_PKEY_derive_set_peer| requires the key implement this command,
+      // even if it is a no-op.
+      return 1;
+
+    default:
+      OPENSSL_PUT_ERROR(EVP, EVP_R_COMMAND_NOT_SUPPORTED);
+      return 0;
+  }
+}
+
+const EVP_PKEY_METHOD x25519_pkey_meth = {
+    EVP_PKEY_X25519,
+    NULL /* init */,
+    pkey_x25519_copy,
+    NULL /* cleanup */,
+    pkey_x25519_keygen,
+    NULL /* sign */,
+    NULL /* sign_message */,
+    NULL /* verify */,
+    NULL /* verify_message */,
+    NULL /* verify_recover */,
+    NULL /* encrypt */,
+    NULL /* decrypt */,
+    pkey_x25519_derive,
+    NULL /* paramgen */,
+    pkey_x25519_ctrl,
+};