漫话Redis源码之五

说真的，看到openssl和tls, 我心好沉重：

void tlsCleanup(void) {
    if (redis_tls_ctx) {
        SSL_CTX_free(redis_tls_ctx);
        redis_tls_ctx = NULL;
    }
    if (redis_tls_client_ctx) {
        SSL_CTX_free(redis_tls_client_ctx);
        redis_tls_client_ctx = NULL;
    }
 
    #if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
    // unavailable on LibreSSL
    OPENSSL_cleanup();
    #endif
}
 
/* Callback for passing a keyfile password stored as an sds to OpenSSL */
static int tlsPasswordCallback(char *buf, int size, int rwflag, void *u) {
    UNUSED(rwflag);
 
    const char *pass = u;
    size_t pass_len;
 
    if (!pass) return -1;
    pass_len = strlen(pass);
    if (pass_len > (size_t) size) return -1;
    memcpy(buf, pass, pass_len);
 
    return (int) pass_len;
}
 
/* Create a *base* SSL_CTX using the SSL configuration provided. The base context
 * includes everything that's common for both client-side and server-side connections.
 */
static SSL_CTX *createSSLContext(redisTLSContextConfig *ctx_config, int protocols, int client) {
    const char *cert_file = client ? ctx_config->client_cert_file : ctx_config->cert_file;
    const char *key_file = client ? ctx_config->client_key_file : ctx_config->key_file;
    const char *key_file_pass = client ? ctx_config->client_key_file_pass : ctx_config->key_file_pass;
    char errbuf[256];
    SSL_CTX *ctx = NULL;
 
    ctx = SSL_CTX_new(SSLv23_method());
 
    SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2|SSL_OP_NO_SSLv3);
 
#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
    SSL_CTX_set_options(ctx, SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS);
#endif
 
    if (!(protocols & REDIS_TLS_PROTO_TLSv1))
        SSL_CTX_set_options(ctx, SSL_OP_NO_TLSv1);
    if (!(protocols & REDIS_TLS_PROTO_TLSv1_1))
        SSL_CTX_set_options(ctx, SSL_OP_NO_TLSv1_1);
#ifdef SSL_OP_NO_TLSv1_2
    if (!(protocols & REDIS_TLS_PROTO_TLSv1_2))
        SSL_CTX_set_options(ctx, SSL_OP_NO_TLSv1_2);
#endif
#ifdef SSL_OP_NO_TLSv1_3
    if (!(protocols & REDIS_TLS_PROTO_TLSv1_3))
        SSL_CTX_set_options(ctx, SSL_OP_NO_TLSv1_3);
#endif
 
#ifdef SSL_OP_NO_COMPRESSION
    SSL_CTX_set_options(ctx, SSL_OP_NO_COMPRESSION);
#endif
 
    SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE|SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
    SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
 
    SSL_CTX_set_default_passwd_cb(ctx, tlsPasswordCallback);
    SSL_CTX_set_default_passwd_cb_userdata(ctx, (void *) key_file_pass);
 
    if (SSL_CTX_use_certificate_chain_file(ctx, cert_file) <= 0) {
        ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
        serverLog(LL_WARNING, "Failed to load certificate: %s: %s", cert_file, errbuf);
        goto error;
    }
 
    if (SSL_CTX_use_PrivateKey_file(ctx, key_file, SSL_FILETYPE_PEM) <= 0) {
        ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
        serverLog(LL_WARNING, "Failed to load private key: %s: %s", key_file, errbuf);
        goto error;
    }
 
    if ((ctx_config->ca_cert_file || ctx_config->ca_cert_dir) &&
        SSL_CTX_load_verify_locations(ctx, ctx_config->ca_cert_file, ctx_config->ca_cert_dir) <= 0) {
        ERR_error_string_n(ERR_get_error(), errbuf, sizeof(errbuf));
        serverLog(LL_WARNING, "Failed to configure CA certificate(s) file/directory: %s", errbuf);
        goto error;
    }
 
    if (ctx_config->ciphers && !SSL_CTX_set_cipher_list(ctx, ctx_config->ciphers)) {
        serverLog(LL_WARNING, "Failed to configure ciphers: %s", ctx_config->ciphers);
        goto error;
    }
 
#ifdef TLS1_3_VERSION
    if (ctx_config->ciphersuites && !SSL_CTX_set_ciphersuites(ctx, ctx_config->ciphersuites)) {
        serverLog(LL_WARNING, "Failed to configure ciphersuites: %s", ctx_config->ciphersuites);
        goto error;
    }
#endif
 
    return ctx;
 
error:
    if (ctx) SSL_CTX_free(ctx);
    return NULL;
}