Peer certificate validation:
Since version 3.4 peer certificate verification is enabled by default.
It can be disabled via `mysql_optionsv`, using option
MYSQL_OPT_SSL_VERIFY_SERVER_CERT:
my_bool verify= 0;
mysql_options(mariadb, MYSQL_OPT_SSL_VERIFY_SERVER_CERT, &verify);
Self signed certificates
If the client obtained a self signed peer certificate from MariaDB server
the verification will fail, with the following exceptions:
* If the connection between client and server is considered to be secure:, e.g.
* a unix_socket is used for client server communication
* hostname is localhost (Windows operating system), 127.0.0.1 or ::1
* a specified fingerprint matches the fingerprint of the peer certificate (see below)
* a client can verify the certificate using account password, it's possible if
* account has a password
* authentication plugin is "secure without TLS", that is, one of
mysql_native_password, ed25519 or parsec.
Fingerprint verification of the peer certificate
A fingerprint is a cryptographic hash (SHA-256, SHA-384 or SHA-512) of the peer
certificate's binary data. Even if the fingerprint matches, an expired or
revoked certificate will not be accepted.
For security reasons support for MD5 and SHA1 has been removed.
Technical details:
==================
- Peer certificate verification call was removed from ma_tls_connect, instead it
will be called directly after the handshake succeeded (my_auth.c)
- mysql->net.tls_self_signed_error was replaced by mysql->net.tls_verify_status which
contains the result of the peer certfificate verification:
The verification status can be obtained with mariadb_get_infov using new parameter
MARIADB_TLS_VERIFY_STATUS.
unsigned int tls_verify_status;
mariadb_get_infov(mysql, MARIADB_TLS_VERIFY_STATUS, &tls_verify_status);
The result is a combination of the following flags:
MARIADB_TLS_VERIFY_OK 0
MARIADB_TLS_VERIFY_TRUST 1
MARIADB_TLS_VERIFY_HOST 2
MARIADB_TLS_VERIFY_PERIOD 4
MARIADB_TLS_VERIFY_FINGERPRINT 8
MARIADB_TLS_VERIFY_REVOKED 16
MARIADB_TLS_VERIFY_UNKNOWN 32
- GnuTLS peer certificate verification callback was removed and replaced by
gnutls_verify_peers2() api function, so the peer certificate validation
will happen after handshake.
- OpenSSL implementation will no longer use SSL_verify_result to check the
validity of the peer certificate. Instead a callback function will be called
during the handshake, which collects all certificate validation errors.
- If the peer certificate is not trusted, hostname verification will be
skipped.
- Testing
Added new test tls, which implements a python based dummy server, which allows
to set different certificates and TLS options. Please note. that tests are
expected to fail, since the server doesn't support further steps like user
authentication etc. after the handshake. Prerequisite for running the tls test
is Python3.
Implement proper verification for server certificate chain,
with refactoring of the certificate stuff.
If custom CA and CRL certs are given, load them into in-memory store, and
use CertVerifyCertificateChainPolicy() to verify the certificate chain.
There are minor errors fixed, such as
- now there is a support for private keys encoded as BEGIN/END PRIVATE KEY
in PEM, instead of only BEGIN/END RSA PRIVATE KEY
- memory leak around CryptAcquireContext() is fixed i.e when client loads
private key, it previously did never released it, not even when connection
ended.
The handling of certificates moved into schannel_certs.c from various places
Added support for pem files which contain certificate and private key.
In case the file will contain more than one certificate or key, the first
certificate or key found will be used.
The connection pointer mysql is now no longer part (and doesn't need to be updated) of schannel security context, since it can be obtained directly from tls container.
between the calls.
State can be unread buffer from DecryptMessage (SECBUFFER_EXTRA)
or decrypted data that did not fit into callers buffer
- Fix error handling - SEC_I_RENEGOTIATE is handled as error,
we're not doing it yet. Stop reading at SEC_I_CONTEXT_EXPIRED.
- Fix buffer sizes pased to SSPI ( so that large buffers can be read or written
"SELECT REPEAT('a', 20000)"
- Fix unchecked memcpy into the output buffer (size of the output buffer
was not checked, so it is a potential memory overrun)
- remove global variables
- remove in memory certificate stores that cache all CRL and all CA
- verify certificate against ssl_ca and ssl_crl specified in
connection options (not against all CRL/CA in store)
changed type of length parameter in mysql_stmt_prepare,
mysql_real_query, mysql_stmt_send_long_data (incl. async _start
functions) from unsigned long to size_t.
Fixed warnings
