diff options
Diffstat (limited to 'src/crypto/tlssession.c')
| -rw-r--r-- | src/crypto/tlssession.c | 574 |
1 files changed, 574 insertions, 0 deletions
diff --git a/src/crypto/tlssession.c b/src/crypto/tlssession.c new file mode 100644 index 0000000..3735529 --- /dev/null +++ b/src/crypto/tlssession.c @@ -0,0 +1,574 @@ +/* + * QEMU crypto TLS session support + * + * Copyright (c) 2015 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + * + */ + +#include "crypto/tlssession.h" +#include "crypto/tlscredsanon.h" +#include "crypto/tlscredsx509.h" +#include "qemu/acl.h" +#include "trace.h" + +#ifdef CONFIG_GNUTLS + + +#include <gnutls/x509.h> + + +struct QCryptoTLSSession { + QCryptoTLSCreds *creds; + gnutls_session_t handle; + char *hostname; + char *aclname; + bool handshakeComplete; + QCryptoTLSSessionWriteFunc writeFunc; + QCryptoTLSSessionReadFunc readFunc; + void *opaque; + char *peername; +}; + + +void +qcrypto_tls_session_free(QCryptoTLSSession *session) +{ + if (!session) { + return; + } + + gnutls_deinit(session->handle); + g_free(session->hostname); + g_free(session->peername); + g_free(session->aclname); + object_unref(OBJECT(session->creds)); + g_free(session); +} + + +static ssize_t +qcrypto_tls_session_push(void *opaque, const void *buf, size_t len) +{ + QCryptoTLSSession *session = opaque; + + if (!session->writeFunc) { + errno = EIO; + return -1; + }; + + return session->writeFunc(buf, len, session->opaque); +} + + +static ssize_t +qcrypto_tls_session_pull(void *opaque, void *buf, size_t len) +{ + QCryptoTLSSession *session = opaque; + + if (!session->readFunc) { + errno = EIO; + return -1; + }; + + return session->readFunc(buf, len, session->opaque); +} + + +QCryptoTLSSession * +qcrypto_tls_session_new(QCryptoTLSCreds *creds, + const char *hostname, + const char *aclname, + QCryptoTLSCredsEndpoint endpoint, + Error **errp) +{ + QCryptoTLSSession *session; + int ret; + + session = g_new0(QCryptoTLSSession, 1); + trace_qcrypto_tls_session_new( + session, creds, hostname ? hostname : "<none>", + aclname ? aclname : "<none>", endpoint); + + if (hostname) { + session->hostname = g_strdup(hostname); + } + if (aclname) { + session->aclname = g_strdup(aclname); + } + session->creds = creds; + object_ref(OBJECT(creds)); + + if (creds->endpoint != endpoint) { + error_setg(errp, "Credentials endpoint doesn't match session"); + goto error; + } + + if (endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { + ret = gnutls_init(&session->handle, GNUTLS_SERVER); + } else { + ret = gnutls_init(&session->handle, GNUTLS_CLIENT); + } + if (ret < 0) { + error_setg(errp, "Cannot initialize TLS session: %s", + gnutls_strerror(ret)); + goto error; + } + + if (object_dynamic_cast(OBJECT(creds), + TYPE_QCRYPTO_TLS_CREDS_ANON)) { + QCryptoTLSCredsAnon *acreds = QCRYPTO_TLS_CREDS_ANON(creds); + + ret = gnutls_priority_set_direct(session->handle, + "NORMAL:+ANON-DH", NULL); + if (ret < 0) { + error_setg(errp, "Unable to set TLS session priority: %s", + gnutls_strerror(ret)); + goto error; + } + if (creds->endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { + ret = gnutls_credentials_set(session->handle, + GNUTLS_CRD_ANON, + acreds->data.server); + } else { + ret = gnutls_credentials_set(session->handle, + GNUTLS_CRD_ANON, + acreds->data.client); + } + if (ret < 0) { + error_setg(errp, "Cannot set session credentials: %s", + gnutls_strerror(ret)); + goto error; + } + } else if (object_dynamic_cast(OBJECT(creds), + TYPE_QCRYPTO_TLS_CREDS_X509)) { + QCryptoTLSCredsX509 *tcreds = QCRYPTO_TLS_CREDS_X509(creds); + + ret = gnutls_set_default_priority(session->handle); + if (ret < 0) { + error_setg(errp, "Cannot set default TLS session priority: %s", + gnutls_strerror(ret)); + goto error; + } + ret = gnutls_credentials_set(session->handle, + GNUTLS_CRD_CERTIFICATE, + tcreds->data); + if (ret < 0) { + error_setg(errp, "Cannot set session credentials: %s", + gnutls_strerror(ret)); + goto error; + } + + if (creds->endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { + /* This requests, but does not enforce a client cert. + * The cert checking code later does enforcement */ + gnutls_certificate_server_set_request(session->handle, + GNUTLS_CERT_REQUEST); + } + } else { + error_setg(errp, "Unsupported TLS credentials type %s", + object_get_typename(OBJECT(creds))); + goto error; + } + + gnutls_transport_set_ptr(session->handle, session); + gnutls_transport_set_push_function(session->handle, + qcrypto_tls_session_push); + gnutls_transport_set_pull_function(session->handle, + qcrypto_tls_session_pull); + + return session; + + error: + qcrypto_tls_session_free(session); + return NULL; +} + +static int +qcrypto_tls_session_check_certificate(QCryptoTLSSession *session, + Error **errp) +{ + int ret; + unsigned int status; + const gnutls_datum_t *certs; + unsigned int nCerts, i; + time_t now; + gnutls_x509_crt_t cert = NULL; + + now = time(NULL); + if (now == ((time_t)-1)) { + error_setg_errno(errp, errno, "Cannot get current time"); + return -1; + } + + ret = gnutls_certificate_verify_peers2(session->handle, &status); + if (ret < 0) { + error_setg(errp, "Verify failed: %s", gnutls_strerror(ret)); + return -1; + } + + if (status != 0) { + const char *reason = "Invalid certificate"; + + if (status & GNUTLS_CERT_INVALID) { + reason = "The certificate is not trusted"; + } + + if (status & GNUTLS_CERT_SIGNER_NOT_FOUND) { + reason = "The certificate hasn't got a known issuer"; + } + + if (status & GNUTLS_CERT_REVOKED) { + reason = "The certificate has been revoked"; + } + + if (status & GNUTLS_CERT_INSECURE_ALGORITHM) { + reason = "The certificate uses an insecure algorithm"; + } + + error_setg(errp, "%s", reason); + return -1; + } + + certs = gnutls_certificate_get_peers(session->handle, &nCerts); + if (!certs) { + error_setg(errp, "No certificate peers"); + return -1; + } + + for (i = 0; i < nCerts; i++) { + ret = gnutls_x509_crt_init(&cert); + if (ret < 0) { + error_setg(errp, "Cannot initialize certificate: %s", + gnutls_strerror(ret)); + return -1; + } + + ret = gnutls_x509_crt_import(cert, &certs[i], GNUTLS_X509_FMT_DER); + if (ret < 0) { + error_setg(errp, "Cannot import certificate: %s", + gnutls_strerror(ret)); + goto error; + } + + if (gnutls_x509_crt_get_expiration_time(cert) < now) { + error_setg(errp, "The certificate has expired"); + goto error; + } + + if (gnutls_x509_crt_get_activation_time(cert) > now) { + error_setg(errp, "The certificate is not yet activated"); + goto error; + } + + if (gnutls_x509_crt_get_activation_time(cert) > now) { + error_setg(errp, "The certificate is not yet activated"); + goto error; + } + + if (i == 0) { + size_t dnameSize = 1024; + session->peername = g_malloc(dnameSize); + requery: + ret = gnutls_x509_crt_get_dn(cert, session->peername, &dnameSize); + if (ret < 0) { + if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER) { + session->peername = g_realloc(session->peername, + dnameSize); + goto requery; + } + error_setg(errp, "Cannot get client distinguished name: %s", + gnutls_strerror(ret)); + goto error; + } + if (session->aclname) { + qemu_acl *acl = qemu_acl_find(session->aclname); + int allow; + if (!acl) { + error_setg(errp, "Cannot find ACL %s", + session->aclname); + goto error; + } + + allow = qemu_acl_party_is_allowed(acl, session->peername); + + if (!allow) { + error_setg(errp, "TLS x509 ACL check for %s is denied", + session->peername); + goto error; + } + } + if (session->hostname) { + if (!gnutls_x509_crt_check_hostname(cert, session->hostname)) { + error_setg(errp, + "Certificate does not match the hostname %s", + session->hostname); + goto error; + } + } + } + + gnutls_x509_crt_deinit(cert); + } + + return 0; + + error: + gnutls_x509_crt_deinit(cert); + return -1; +} + + +int +qcrypto_tls_session_check_credentials(QCryptoTLSSession *session, + Error **errp) +{ + if (object_dynamic_cast(OBJECT(session->creds), + TYPE_QCRYPTO_TLS_CREDS_ANON)) { + return 0; + } else if (object_dynamic_cast(OBJECT(session->creds), + TYPE_QCRYPTO_TLS_CREDS_X509)) { + if (session->creds->verifyPeer) { + return qcrypto_tls_session_check_certificate(session, + errp); + } else { + return 0; + } + } else { + error_setg(errp, "Unexpected credential type %s", + object_get_typename(OBJECT(session->creds))); + return -1; + } +} + + +void +qcrypto_tls_session_set_callbacks(QCryptoTLSSession *session, + QCryptoTLSSessionWriteFunc writeFunc, + QCryptoTLSSessionReadFunc readFunc, + void *opaque) +{ + session->writeFunc = writeFunc; + session->readFunc = readFunc; + session->opaque = opaque; +} + + +ssize_t +qcrypto_tls_session_write(QCryptoTLSSession *session, + const char *buf, + size_t len) +{ + ssize_t ret = gnutls_record_send(session->handle, buf, len); + + if (ret < 0) { + switch (ret) { + case GNUTLS_E_AGAIN: + errno = EAGAIN; + break; + case GNUTLS_E_INTERRUPTED: + errno = EINTR; + break; + default: + errno = EIO; + break; + } + ret = -1; + } + + return ret; +} + + +ssize_t +qcrypto_tls_session_read(QCryptoTLSSession *session, + char *buf, + size_t len) +{ + ssize_t ret = gnutls_record_recv(session->handle, buf, len); + + if (ret < 0) { + switch (ret) { + case GNUTLS_E_AGAIN: + errno = EAGAIN; + break; + case GNUTLS_E_INTERRUPTED: + errno = EINTR; + break; + default: + errno = EIO; + break; + } + ret = -1; + } + + return ret; +} + + +int +qcrypto_tls_session_handshake(QCryptoTLSSession *session, + Error **errp) +{ + int ret = gnutls_handshake(session->handle); + if (ret == 0) { + session->handshakeComplete = true; + } else { + if (ret == GNUTLS_E_INTERRUPTED || + ret == GNUTLS_E_AGAIN) { + ret = 1; + } else { + error_setg(errp, "TLS handshake failed: %s", + gnutls_strerror(ret)); + ret = -1; + } + } + + return ret; +} + + +QCryptoTLSSessionHandshakeStatus +qcrypto_tls_session_get_handshake_status(QCryptoTLSSession *session) +{ + if (session->handshakeComplete) { + return QCRYPTO_TLS_HANDSHAKE_COMPLETE; + } else if (gnutls_record_get_direction(session->handle) == 0) { + return QCRYPTO_TLS_HANDSHAKE_RECVING; + } else { + return QCRYPTO_TLS_HANDSHAKE_SENDING; + } +} + + +int +qcrypto_tls_session_get_key_size(QCryptoTLSSession *session, + Error **errp) +{ + gnutls_cipher_algorithm_t cipher; + int ssf; + + cipher = gnutls_cipher_get(session->handle); + ssf = gnutls_cipher_get_key_size(cipher); + if (!ssf) { + error_setg(errp, "Cannot get TLS cipher key size"); + return -1; + } + return ssf; +} + + +char * +qcrypto_tls_session_get_peer_name(QCryptoTLSSession *session) +{ + if (session->peername) { + return g_strdup(session->peername); + } + return NULL; +} + + +#else /* ! CONFIG_GNUTLS */ + + +QCryptoTLSSession * +qcrypto_tls_session_new(QCryptoTLSCreds *creds G_GNUC_UNUSED, + const char *hostname G_GNUC_UNUSED, + const char *aclname G_GNUC_UNUSED, + QCryptoTLSCredsEndpoint endpoint G_GNUC_UNUSED, + Error **errp) +{ + error_setg(errp, "TLS requires GNUTLS support"); + return NULL; +} + + +void +qcrypto_tls_session_free(QCryptoTLSSession *sess G_GNUC_UNUSED) +{ +} + + +int +qcrypto_tls_session_check_credentials(QCryptoTLSSession *sess G_GNUC_UNUSED, + Error **errp) +{ + error_setg(errp, "TLS requires GNUTLS support"); + return -1; +} + + +void +qcrypto_tls_session_set_callbacks( + QCryptoTLSSession *sess G_GNUC_UNUSED, + QCryptoTLSSessionWriteFunc writeFunc G_GNUC_UNUSED, + QCryptoTLSSessionReadFunc readFunc G_GNUC_UNUSED, + void *opaque G_GNUC_UNUSED) +{ +} + + +ssize_t +qcrypto_tls_session_write(QCryptoTLSSession *sess, + const char *buf, + size_t len) +{ + errno = -EIO; + return -1; +} + + +ssize_t +qcrypto_tls_session_read(QCryptoTLSSession *sess, + char *buf, + size_t len) +{ + errno = -EIO; + return -1; +} + + +int +qcrypto_tls_session_handshake(QCryptoTLSSession *sess, + Error **errp) +{ + error_setg(errp, "TLS requires GNUTLS support"); + return -1; +} + + +QCryptoTLSSessionHandshakeStatus +qcrypto_tls_session_get_handshake_status(QCryptoTLSSession *sess) +{ + return QCRYPTO_TLS_HANDSHAKE_COMPLETE; +} + + +int +qcrypto_tls_session_get_key_size(QCryptoTLSSession *sess, + Error **errp) +{ + error_setg(errp, "TLS requires GNUTLS support"); + return -1; +} + + +char * +qcrypto_tls_session_get_peer_name(QCryptoTLSSession *sess) +{ + return NULL; +} + +#endif |
