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121 lines
3.6 KiB
121 lines
3.6 KiB
/* crypto.c - LMDB encryption helper module */
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/*
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* Copyright 2020 Howard Chu, Symas Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted only as authorized by the Symas
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* Dual-Use License.
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*
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* A copy of this license is available in the file LICENSE in the
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* source distribution.
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*/
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#include <string.h>
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#include <openssl/engine.h>
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#include "lmdb.h"
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MDB_crypto_hooks MDB_crypto;
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static EVP_CIPHER *cipher;
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static int mcf_str2key(const char *passwd, MDB_val *key)
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{
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unsigned int size;
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EVP_MD_CTX *mdctx = EVP_MD_CTX_new();
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EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL);
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EVP_DigestUpdate(mdctx, "Just a Constant", sizeof("Just a Constant"));
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EVP_DigestUpdate(mdctx, passwd, strlen(passwd));
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EVP_DigestFinal_ex(mdctx, key->mv_data, &size);
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EVP_MD_CTX_free(mdctx);
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return 0;
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}
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/* cheats - internal OpenSSL 1.1 structures */
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typedef struct evp_cipher_ctx_st {
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const EVP_CIPHER *cipher;
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ENGINE *engine; /* functional reference if 'cipher' is
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* ENGINE-provided */
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int encrypt; /* encrypt or decrypt */
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int buf_len; /* number we have left */
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unsigned char oiv[EVP_MAX_IV_LENGTH]; /* original iv */
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unsigned char iv[EVP_MAX_IV_LENGTH]; /* working iv */
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unsigned char buf[EVP_MAX_BLOCK_LENGTH]; /* saved partial block */
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int num; /* used by cfb/ofb/ctr mode */
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/* FIXME: Should this even exist? It appears unused */
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void *app_data; /* application stuff */
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int key_len; /* May change for variable length cipher */
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unsigned long flags; /* Various flags */
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void *cipher_data; /* per EVP data */
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int final_used;
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int block_mask;
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unsigned char final[EVP_MAX_BLOCK_LENGTH]; /* possible final block */
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} EVP_CIPHER_CTX;
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#define CHACHA_KEY_SIZE 32
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#define CHACHA_CTR_SIZE 16
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#define CHACHA_BLK_SIZE 64
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#define POLY1305_BLOCK_SIZE 16
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typedef struct {
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union {
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double align; /* this ensures even sizeof(EVP_CHACHA_KEY)%8==0 */
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unsigned int d[CHACHA_KEY_SIZE / 4];
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} key;
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unsigned int counter[CHACHA_CTR_SIZE / 4];
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unsigned char buf[CHACHA_BLK_SIZE];
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unsigned int partial_len;
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} EVP_CHACHA_KEY;
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typedef struct {
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EVP_CHACHA_KEY key;
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unsigned int nonce[12/4];
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unsigned char tag[POLY1305_BLOCK_SIZE];
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unsigned char tls_aad[POLY1305_BLOCK_SIZE];
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struct { uint64_t aad, text; } len;
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int aad, mac_inited, tag_len, nonce_len;
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size_t tls_payload_length;
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} EVP_CHACHA_AEAD_CTX;
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static int mcf_encfunc(const MDB_val *src, MDB_val *dst, const MDB_val *key, int encdec)
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{
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unsigned char iv[12];
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int ivl, outl, rc;
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mdb_size_t *ptr;
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EVP_CIPHER_CTX ctx = {0};
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EVP_CHACHA_AEAD_CTX cactx;
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ctx.cipher_data = &cactx;
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ptr = key[1].mv_data;
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ivl = ptr[0] & 0xffffffff;
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memcpy(iv, &ivl, 4);
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memcpy(iv+4, ptr+1, sizeof(mdb_size_t));
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EVP_CipherInit_ex(&ctx, cipher, NULL, key[0].mv_data, iv, encdec);
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EVP_CIPHER_CTX_set_padding(&ctx, 0);
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if (!encdec) {
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EVP_CIPHER_CTX_ctrl(&ctx, EVP_CTRL_AEAD_SET_TAG, key[2].mv_size, key[2].mv_data);
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}
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rc = EVP_CipherUpdate(&ctx, dst->mv_data, &outl, src->mv_data, src->mv_size);
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if (rc)
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rc = EVP_CipherFinal_ex(&ctx, key[2].mv_data, &outl);
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if (rc && encdec) {
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EVP_CIPHER_CTX_ctrl(&ctx, EVP_CTRL_AEAD_GET_TAG, key[2].mv_size, key[2].mv_data);
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}
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return rc == 0;
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}
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static const MDB_crypto_funcs mcf_table = {
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mcf_str2key,
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mcf_encfunc,
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NULL,
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CHACHA_KEY_SIZE,
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POLY1305_BLOCK_SIZE,
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0
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};
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MDB_crypto_funcs *MDB_crypto()
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{
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cipher = (EVP_CIPHER *)EVP_chacha20_poly1305();
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return (MDB_crypto_funcs *)&mcf_table;
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}
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