epee: add SSL support

RPC connections now have optional tranparent SSL.

An optional private key and certificate file can be passed,
using the --{rpc,daemon}-ssl-private-key and
--{rpc,daemon}-ssl-certificate options. Those have as
argument a path to a PEM format private private key and
certificate, respectively.
If not given, a temporary self signed certificate will be used.

SSL can be enabled or disabled using --{rpc}-ssl, which
accepts autodetect (default), disabled or enabled.

Access can be restricted to particular certificates using the
--rpc-ssl-allowed-certificates, which takes a list of
paths to PEM encoded certificates. This can allow a wallet to
connect to only the daemon they think they're connected to,
by forcing SSL and listing the paths to the known good
certificates.

To generate long term certificates:

openssl genrsa -out /tmp/KEY 4096
openssl req -new -key /tmp/KEY -out /tmp/REQ
openssl x509 -req -days 999999 -sha256 -in /tmp/REQ -signkey /tmp/KEY -out /tmp/CERT

/tmp/KEY is the private key, and /tmp/CERT is the certificate,
both in PEM format. /tmp/REQ can be removed. Adjust the last
command to set expiration date, etc, as needed. It doesn't
make a whole lot of sense for monero anyway, since most servers
will run with one time temporary self signed certificates anyway.

SSL support is transparent, so all communication is done on the
existing ports, with SSL autodetection. This means you can start
using an SSL daemon now, but you should not enforce SSL yet or
nothing will talk to you.
This commit is contained in:
Martijn Otto 2018-06-14 23:44:48 +01:00
parent 39d7d3113b
commit 057c279cb4
No known key found for this signature in database
GPG key ID: D2E0D5D0B1D606F9
15 changed files with 200 additions and 49 deletions

View file

@ -83,4 +83,67 @@ namespace epee
{
return write_hex(out, src);
}
std::vector<uint8_t> from_hex::vector(boost::string_ref src)
{
// should we include a specific character
auto include = [](char input) {
// we ignore spaces and colons
return !std::isspace(input) && input != ':';
};
// the number of relevant characters to decode
auto count = std::count_if(src.begin(), src.end(), include);
// this must be a multiple of two, otherwise we have a truncated input
if (count % 2) {
throw std::length_error{ "Invalid hexadecimal input length" };
}
std::vector<uint8_t> result;
result.reserve(count / 2);
// the data to work with (std::string is always null-terminated)
auto data = src.data();
// convert a single hex character to an unsigned integer
auto char_to_int = [](const char *input) {
switch (std::tolower(*input)) {
case '0': return 0;
case '1': return 1;
case '2': return 2;
case '3': return 3;
case '4': return 4;
case '5': return 5;
case '6': return 6;
case '7': return 7;
case '8': return 8;
case '9': return 9;
case 'a': return 10;
case 'b': return 11;
case 'c': return 12;
case 'd': return 13;
case 'e': return 14;
case 'f': return 15;
default: throw std::range_error{ "Invalid hexadecimal input" };
}
};
// keep going until we reach the end
while (data[0] != '\0') {
// skip unwanted characters
if (!include(data[0])) {
++data;
continue;
}
// convert two matching characters to int
auto high = char_to_int(data++);
auto low = char_to_int(data++);
result.push_back(high << 4 | low);
}
return result;
}
}

View file

@ -154,13 +154,19 @@ bool create_ssl_certificate(std::string &pkey_buffer, std::string &cert_buffer)
return success;
}
ssl_context_t create_ssl_context(const std::pair<std::string, std::string> &private_key_and_certificate_path, std::list<std::string> allowed_certificates, bool allow_any_cert)
ssl_context_t create_ssl_context(const std::pair<std::string, std::string> &private_key_and_certificate_path, std::list<std::string> allowed_certificates, std::vector<std::vector<uint8_t>> allowed_fingerprints, bool allow_any_cert)
{
ssl_context_t ssl_context({boost::asio::ssl::context(boost::asio::ssl::context::sslv23), std::move(allowed_certificates)});
ssl_context_t ssl_context{boost::asio::ssl::context(boost::asio::ssl::context::tlsv12), std::move(allowed_certificates), std::move(allowed_fingerprints)};
// disable sslv2
ssl_context.context.set_options(boost::asio::ssl::context::default_workarounds | boost::asio::ssl::context::no_sslv2);
ssl_context.context.set_default_verify_paths();
// only allow tls v1.2 and up
ssl_context.context.set_options(boost::asio::ssl::context::default_workarounds);
ssl_context.context.set_options(boost::asio::ssl::context::no_sslv2);
ssl_context.context.set_options(boost::asio::ssl::context::no_sslv3);
ssl_context.context.set_options(boost::asio::ssl::context::no_tlsv1);
ssl_context.context.set_options(boost::asio::ssl::context::no_tlsv1_1);
// only allow a select handful of tls v1.3 and v1.2 ciphers to be used
SSL_CTX_set_cipher_list(ssl_context.context.native_handle(), "ECDHE-ECDSA-CHACHA20-POLY1305-SHA256:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-CHACHA20-POLY1305");
// set options on the SSL context for added security
SSL_CTX *ctx = ssl_context.context.native_handle();
@ -179,7 +185,7 @@ ssl_context_t create_ssl_context(const std::pair<std::string, std::string> &priv
#ifdef SSL_OP_NO_COMPRESSION
SSL_CTX_set_options(ctx, SSL_OP_NO_COMPRESSION);
#endif
SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1 | SSL_OP_NO_TLSv1_1); // https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices
ssl_context.context.set_default_verify_paths();
CHECK_AND_ASSERT_THROW_MES(private_key_and_certificate_path.first.empty() == private_key_and_certificate_path.second.empty(), "private key and certificate must be either both given or both empty");
if (private_key_and_certificate_path.second.empty())
@ -225,7 +231,7 @@ bool is_ssl(const unsigned char *data, size_t len)
return false;
}
bool is_certificate_allowed(boost::asio::ssl::verify_context &ctx, const std::list<std::string> &allowed_certificates)
bool is_certificate_allowed(boost::asio::ssl::verify_context &ctx, const ssl_context_t &ssl_context)
{
X509_STORE_CTX *sctx = ctx.native_handle();
if (!sctx)
@ -240,23 +246,51 @@ bool is_certificate_allowed(boost::asio::ssl::verify_context &ctx, const std::li
return false;
}
BIO *bio_cert = BIO_new(BIO_s_mem());
openssl_bio bio_cert_deleter{bio_cert};
bool success = PEM_write_bio_X509(bio_cert, cert);
if (!success)
{
MERROR("Failed to print certificate");
return false;
// can we check the certificate against a list of fingerprints?
if (!ssl_context.allowed_fingerprints.empty()) {
// buffer for the certificate digest and the size of the result
std::vector<uint8_t> digest(EVP_MAX_MD_SIZE);
unsigned int size{ 0 };
// create the digest from the certificate
if (!X509_digest(cert, EVP_sha1(), digest.data(), &size)) {
MERROR("Failed to create certificate fingerprint");
return false;
}
// strip unnecessary bytes from the digest
digest.resize(size);
// is the certificate fingerprint inside the list of allowed fingerprints?
if (std::find(ssl_context.allowed_fingerprints.begin(), ssl_context.allowed_fingerprints.end(), digest) != ssl_context.allowed_fingerprints.end())
return true;
}
BUF_MEM *buf = NULL;
BIO_get_mem_ptr(bio_cert, &buf);
if (!buf || !buf->data || !buf->length)
{
MERROR("Failed to write certificate: " << ERR_get_error());
return false;
if (!ssl_context.allowed_certificates.empty()) {
BIO *bio_cert = BIO_new(BIO_s_mem());
bool success = PEM_write_bio_X509(bio_cert, cert);
if (!success)
{
BIO_free(bio_cert);
MERROR("Failed to print certificate");
return false;
}
BUF_MEM *buf = NULL;
BIO_get_mem_ptr(bio_cert, &buf);
if (!buf || !buf->data || !buf->length)
{
BIO_free(bio_cert);
MERROR("Failed to write certificate: " << ERR_get_error());
return false;
}
std::string certificate(std::string(buf->data, buf->length));
BIO_free(bio_cert);
if (std::find(ssl_context.allowed_certificates.begin(), ssl_context.allowed_certificates.end(), certificate) != ssl_context.allowed_certificates.end())
return true;
}
std::string certificate(std::string(buf->data, buf->length));
return std::find(allowed_certificates.begin(), allowed_certificates.end(), certificate) != allowed_certificates.end();
// if either checklist is non-empty we must have failed it
return ssl_context.allowed_fingerprints.empty() && ssl_context.allowed_certificates.empty();
}
bool ssl_handshake(boost::asio::ssl::stream<boost::asio::ip::tcp::socket> &socket, boost::asio::ssl::stream_base::handshake_type type, const epee::net_utils::ssl_context_t &ssl_context)
@ -276,7 +310,7 @@ bool ssl_handshake(boost::asio::ssl::stream<boost::asio::ip::tcp::socket> &socke
return false;
}
}
if (!ssl_context.allow_any_cert && !ssl_context.allowed_certificates.empty() && !is_certificate_allowed(ctx, ssl_context.allowed_certificates))
if (!ssl_context.allow_any_cert && !is_certificate_allowed(ctx, ssl_context))
{
MERROR("Certificate is not in the allowed list, connection droppped");
return false;
@ -289,7 +323,7 @@ bool ssl_handshake(boost::asio::ssl::stream<boost::asio::ip::tcp::socket> &socke
socket.handshake(type, ec);
if (ec)
{
MERROR("handshake failed, connection dropped");
MERROR("handshake failed, connection dropped: " << ec.message());
return false;
}
if (!ssl_context.allow_any_cert && !verified)