Pete Bentley | 0c61efe | 2019-08-13 09:32:23 +0100 | [diff] [blame^] | 1 | /* Copyright (c) 2019, Google Inc. |
| 2 | * |
| 3 | * Permission to use, copy, modify, and/or distribute this software for any |
| 4 | * purpose with or without fee is hereby granted, provided that the above |
| 5 | * copyright notice and this permission notice appear in all copies. |
| 6 | * |
| 7 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 8 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 9 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| 10 | * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 11 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| 12 | * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| 13 | * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ |
| 14 | |
| 15 | #include <openssl/evp.h> |
| 16 | |
| 17 | #include <openssl/curve25519.h> |
| 18 | #include <openssl/err.h> |
| 19 | #include <openssl/mem.h> |
| 20 | |
| 21 | #include "internal.h" |
| 22 | |
| 23 | |
| 24 | // X25519 has no parameters to copy. |
| 25 | static int pkey_x25519_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) { return 1; } |
| 26 | |
| 27 | static int pkey_x25519_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) { |
| 28 | X25519_KEY *key = OPENSSL_malloc(sizeof(X25519_KEY)); |
| 29 | if (key == NULL) { |
| 30 | OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE); |
| 31 | return 0; |
| 32 | } |
| 33 | |
| 34 | if (!EVP_PKEY_set_type(pkey, EVP_PKEY_X25519)) { |
| 35 | OPENSSL_free(key); |
| 36 | return 0; |
| 37 | } |
| 38 | |
| 39 | X25519_keypair(key->pub, key->priv); |
| 40 | key->has_private = 1; |
| 41 | |
| 42 | OPENSSL_free(pkey->pkey.ptr); |
| 43 | pkey->pkey.ptr = key; |
| 44 | return 1; |
| 45 | } |
| 46 | |
| 47 | static int pkey_x25519_derive(EVP_PKEY_CTX *ctx, uint8_t *out, |
| 48 | size_t *out_len) { |
| 49 | if (ctx->pkey == NULL || ctx->peerkey == NULL) { |
| 50 | OPENSSL_PUT_ERROR(EVP, EVP_R_KEYS_NOT_SET); |
| 51 | return 0; |
| 52 | } |
| 53 | |
| 54 | const X25519_KEY *our_key = ctx->pkey->pkey.ptr; |
| 55 | const X25519_KEY *peer_key = ctx->peerkey->pkey.ptr; |
| 56 | if (our_key == NULL || peer_key == NULL) { |
| 57 | OPENSSL_PUT_ERROR(EVP, EVP_R_KEYS_NOT_SET); |
| 58 | return 0; |
| 59 | } |
| 60 | |
| 61 | if (!our_key->has_private) { |
| 62 | OPENSSL_PUT_ERROR(EVP, EVP_R_NOT_A_PRIVATE_KEY); |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | if (out != NULL) { |
| 67 | if (*out_len < 32) { |
| 68 | OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL); |
| 69 | return 0; |
| 70 | } |
| 71 | if (!X25519(out, our_key->priv, peer_key->pub)) { |
| 72 | OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PEER_KEY); |
| 73 | return 0; |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | *out_len = 32; |
| 78 | return 1; |
| 79 | } |
| 80 | |
| 81 | static int pkey_x25519_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) { |
| 82 | switch (type) { |
| 83 | case EVP_PKEY_CTRL_PEER_KEY: |
| 84 | // |EVP_PKEY_derive_set_peer| requires the key implement this command, |
| 85 | // even if it is a no-op. |
| 86 | return 1; |
| 87 | |
| 88 | default: |
| 89 | OPENSSL_PUT_ERROR(EVP, EVP_R_COMMAND_NOT_SUPPORTED); |
| 90 | return 0; |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | const EVP_PKEY_METHOD x25519_pkey_meth = { |
| 95 | EVP_PKEY_X25519, |
| 96 | NULL /* init */, |
| 97 | pkey_x25519_copy, |
| 98 | NULL /* cleanup */, |
| 99 | pkey_x25519_keygen, |
| 100 | NULL /* sign */, |
| 101 | NULL /* sign_message */, |
| 102 | NULL /* verify */, |
| 103 | NULL /* verify_message */, |
| 104 | NULL /* verify_recover */, |
| 105 | NULL /* encrypt */, |
| 106 | NULL /* decrypt */, |
| 107 | pkey_x25519_derive, |
| 108 | NULL /* paramgen */, |
| 109 | pkey_x25519_ctrl, |
| 110 | }; |