Provided by: libmongoc-doc_1.26.0-1.1ubuntu2_all 
CONFIGURATION WITH URI OPTIONS
Enable TLS by including tls=true in the URI.
mongoc_uri_t *uri = mongoc_uri_new ("mongodb://localhost:27017/");
mongoc_uri_set_option_as_bool (uri, MONGOC_URI_TLS, true);
mongoc_client_t *client = mongoc_client_new_from_uri (uri);
The following URI options may be used to further configure TLS:
┌────────────────────────────────────────────────┬──────────────────────────────────────┬────────────────────────────────────────┐
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
├────────────────────────────────────────────────┼──────────────────────────────────────┼────────────────────────────────────────┤
└────────────────────────────────────────────────┴──────────────────────────────────────┴────────────────────────────────────────┘
CONFIGURATION WITH MONGOC_SSL_OPT_T
Alternatively, the mongoc_ssl_opt_t struct may be used to configure TLS with
mongoc_client_set_ssl_opts() or mongoc_client_pool_set_ssl_opts(). Most of the
configurable options can be set using the Connection String URI.
┌───────────────────────┬─────────────────────────────────┐
│mongoc_ssl_opt_t key │ URI key │
├───────────────────────┼─────────────────────────────────┤
│pem_file │ tlsClientCertificateKeyFile │
├───────────────────────┼─────────────────────────────────┤
│pem_pwd │ tlsClientCertificateKeyPassword │
├───────────────────────┼─────────────────────────────────┤
│ca_file │ tlsCAFile │
├───────────────────────┼─────────────────────────────────┤
│weak_cert_validation │ tlsAllowInvalidCertificates │
├───────────────────────┼─────────────────────────────────┤
│allow_invalid_hostname │ tlsAllowInvalidHostnames │
└───────────────────────┴─────────────────────────────────┘
The only exclusions are crl_file and ca_dir. Those may only be set with mongoc_ssl_opt_t.
CLIENT AUTHENTICATION
When MongoDB is started with TLS enabled, it will by default require the client to provide
a client certificate issued by a certificate authority specified by --tlsCAFile, or an
authority trusted by the native certificate store in use on the server.
To provide the client certificate, set the tlsCertificateKeyFile in the URI to a PEM
armored certificate file.
mongoc_uri_t *uri = mongoc_uri_new ("mongodb://localhost:27017/");
mongoc_uri_set_option_as_bool (uri, MONGOC_URI_TLS, true);
mongoc_uri_set_option_as_utf8 (uri, MONGOC_URI_TLSCERTIFICATEKEYFILE, "/path/to/client-certificate.pem");
mongoc_client_t *client = mongoc_client_new_from_uri (uri);
SERVER CERTIFICATE VERIFICATION
The MongoDB C Driver will automatically verify the validity of the server certificate,
such as issued by configured Certificate Authority, hostname validation, and expiration.
To overwrite this behavior, it is possible to disable hostname validation, OCSP endpoint
revocation checking, revocation checking entirely, and allow invalid certificates.
This behavior is controlled using the tlsAllowInvalidHostnames,
tlsDisableOCSPEndpointCheck, tlsDisableCertificateRevocationCheck, and
tlsAllowInvalidCertificates options respectively. By default, all are set to false.
It is not recommended to change these defaults as it exposes the client to Man In The
Middle attacks (when tlsAllowInvalidHostnames is set), invalid certificates (when
tlsAllowInvalidCertificates is set), or potentially revoked certificates (when
tlsDisableOCSPEndpointCheck or tlsDisableCertificateRevocationCheck are set).
SUPPORTED LIBRARIES
By default, libmongoc will attempt to find a supported TLS library and enable TLS support.
This is controlled by the cmake flag ENABLE_SSL, which is set to AUTO by default. Valid
values are:
• AUTO the default behavior. Link to the system's native TLS library, or attempt to find
OpenSSL.
• DARWIN link to Secure Transport, the native TLS library on macOS.
• WINDOWS link to Secure Channel, the native TLS library on Windows.
• OPENSSL link to OpenSSL (libssl). An optional install path may be specified with
OPENSSL_ROOT.
• LIBRESSL link to LibreSSL's libtls. (LibreSSL's compatible libssl may be linked to by
setting OPENSSL).
• OFF disable TLS support.
OpenSSL
The MongoDB C Driver uses OpenSSL, if available, on Linux and Unix platforms (besides
macOS). Industry best practices and some regulations require the use of TLS 1.1 or newer,
which requires at least OpenSSL 1.0.1. Check your OpenSSL version like so:
$ openssl version
Ensure your system's OpenSSL is a recent version (at least 1.0.1), or install a recent
version in a non-system path and build against it with:
cmake -DOPENSSL_ROOT_DIR=/absolute/path/to/openssl
When compiled against OpenSSL, the driver will attempt to load the system default
certificate store, as configured by the distribution. That can be overridden by setting
the tlsCAFile URI option or with the fields ca_file and ca_dir in the mongoc_ssl_opt_t.
The Online Certificate Status Protocol (OCSP) (see RFC 6960) is fully supported when using
OpenSSL 1.0.1+ with the following notes:
• When a crl_file is set with mongoc_ssl_opt_t, and the crl_file revokes the server's
certificate, the certificate is considered revoked (even if the certificate has a valid
stapled OCSP response)
LibreSSL / libtls
The MongoDB C Driver supports LibreSSL through the use of OpenSSL compatibility checks
when configured to compile against openssl. It also supports the new libtls library when
configured to build against libressl.
When compiled against the Windows native libraries, the crl_file option of a
mongoc_ssl_opt_t is not supported, and will issue an error if used.
Setting tlsDisableOCSPEndpointCheck and tlsDisableCertificateRevocationCheck has no
effect.
The Online Certificate Status Protocol (OCSP) (see RFC 6960) is partially supported with
the following notes:
• The Must-Staple extension (see RFC 7633) is ignored. Connection may continue if a
Must-Staple certificate is presented with no stapled response (unless the client
receives a revoked response from an OCSP responder).
• Connection will continue if a Must-Staple certificate is presented without a stapled
response and the OCSP responder is down.
Native TLS Support on Windows (Secure Channel)
The MongoDB C Driver supports the Windows native TLS library (Secure Channel, or
SChannel), and its native crypto library (Cryptography API: Next Generation, or CNG).
When compiled against the Windows native libraries, the ca_dir option of a
mongoc_ssl_opt_t is not supported, and will issue an error if used.
Encrypted PEM files (e.g., setting tlsCertificateKeyPassword) are also not supported, and
will result in error when attempting to load them.
When tlsCAFile is set, the driver will only allow server certificates issued by the
authority (or authorities) provided. When no tlsCAFile is set, the driver will look up the
Certificate Authority using the System Local Machine Root certificate store to confirm the
provided certificate.
When crl_file is set with mongoc_ssl_opt_t, the driver will import the revocation list to
the System Local Machine Root certificate store.
Setting tlsDisableOCSPEndpointCheck has no effect.
The Online Certificate Status Protocol (OCSP) (see RFC 6960) is partially supported with
the following notes:
• The Must-Staple extension (see RFC 7633) is ignored. Connection may continue if a
Must-Staple certificate is presented with no stapled response (unless the client
receives a revoked response from an OCSP responder).
• When a crl_file is set with mongoc_ssl_opt_t, and the crl_file revokes the server's
certificate, the OCSP response takes precedence. E.g. if the server presents a
certificate with a valid stapled OCSP response, the certificate is considered valid even
if the crl_file marks it as revoked.
• Connection will continue if a Must-Staple certificate is presented without a stapled
response and the OCSP responder is down.
Native TLS Support on macOS / Darwin (Secure Transport)
The MongoDB C Driver supports the Darwin (OS X, macOS, iOS, etc.) native TLS library
(Secure Transport), and its native crypto library (Common Crypto, or CC).
When compiled against Secure Transport, the ca_dir and crl_file options of a
mongoc_ssl_opt_t are not supported. An error is issued if either are used.
When tlsCAFile is set, the driver will only allow server certificates issued by the
authority (or authorities) provided. When no tlsCAFile is set, the driver will use the
Certificate Authorities in the currently unlocked keychains.
Setting tlsDisableOCSPEndpointCheck and tlsDisableCertificateRevocationCheck has no
effect.
The Online Certificate Status Protocol (OCSP) (see RFC 6960) is partially supported with
the following notes.
• The Must-Staple extension (see RFC 7633) is ignored. Connection may continue if a
Must-Staple certificate is presented with no stapled response (unless the client
receives a revoked response from an OCSP responder).
• Connection will continue if a Must-Staple certificate is presented without a stapled
response and the OCSP responder is down.
AUTHOR
MongoDB, Inc
COPYRIGHT
2017-present, MongoDB, Inc