crypto: add support for TLS priority string override
The gnutls default priority is either "NORMAL" (most historical
versions of gnutls) which is a built-in label in gnutls code,
or "@SYSTEM" (latest gnutls on Fedora at least) which refers
to an admin customizable entry in a gnutls config file.
Regardless of which default is used by a distro, they are both
global defaults applying to all applications using gnutls. If
a single application on the system needs to use a weaker set
of crypto priorities, this potentially forces the weakness onto
all applications. Or conversely if a single application wants a
strong default than all others, it can't do this via the global
config file.
This adds an extra parameter to the tls credential object which
allows the mgmt app / user to explicitly provide a priority
string to QEMU when configuring TLS.
For example, to use the "NORMAL" priority, but disable SSL 3.0
one can now configure QEMU thus:
$QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\
priority="NORMAL:-VERS-SSL3.0" \
..other args...
If creating tls-creds-anon, whatever priority the user specifies
will always have "+ANON-DH" appended to it, since that's mandatory
to make the anonymous credentials work.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
diff --git a/crypto/tlscreds.c b/crypto/tlscreds.c
index 1620e12..a896553 100644
--- a/crypto/tlscreds.c
+++ b/crypto/tlscreds.c
@@ -179,6 +179,27 @@
static void
+qcrypto_tls_creds_prop_set_priority(Object *obj,
+ const char *value,
+ Error **errp G_GNUC_UNUSED)
+{
+ QCryptoTLSCreds *creds = QCRYPTO_TLS_CREDS(obj);
+
+ creds->priority = g_strdup(value);
+}
+
+
+static char *
+qcrypto_tls_creds_prop_get_priority(Object *obj,
+ Error **errp G_GNUC_UNUSED)
+{
+ QCryptoTLSCreds *creds = QCRYPTO_TLS_CREDS(obj);
+
+ return g_strdup(creds->priority);
+}
+
+
+static void
qcrypto_tls_creds_prop_set_endpoint(Object *obj,
int value,
Error **errp G_GNUC_UNUSED)
@@ -216,6 +237,10 @@
qcrypto_tls_creds_prop_get_endpoint,
qcrypto_tls_creds_prop_set_endpoint,
NULL);
+ object_class_property_add_str(oc, "priority",
+ qcrypto_tls_creds_prop_get_priority,
+ qcrypto_tls_creds_prop_set_priority,
+ NULL);
}
@@ -234,6 +259,7 @@
QCryptoTLSCreds *creds = QCRYPTO_TLS_CREDS(obj);
g_free(creds->dir);
+ g_free(creds->priority);
}
diff --git a/crypto/tlssession.c b/crypto/tlssession.c
index a543e5a..2112d29 100644
--- a/crypto/tlssession.c
+++ b/crypto/tlssession.c
@@ -132,14 +132,22 @@
if (object_dynamic_cast(OBJECT(creds),
TYPE_QCRYPTO_TLS_CREDS_ANON)) {
QCryptoTLSCredsAnon *acreds = QCRYPTO_TLS_CREDS_ANON(creds);
+ char *prio;
- ret = gnutls_priority_set_direct(session->handle,
- "NORMAL:+ANON-DH", NULL);
+ if (creds->priority != NULL) {
+ prio = g_strdup_printf("%s:+ANON-DH", creds->priority);
+ } else {
+ prio = g_strdup("NORMAL:+ANON-DH");
+ }
+
+ ret = gnutls_priority_set_direct(session->handle, prio, NULL);
if (ret < 0) {
- error_setg(errp, "Unable to set TLS session priority: %s",
- gnutls_strerror(ret));
+ error_setg(errp, "Unable to set TLS session priority %s: %s",
+ prio, gnutls_strerror(ret));
+ g_free(prio);
goto error;
}
+ g_free(prio);
if (creds->endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
ret = gnutls_credentials_set(session->handle,
GNUTLS_CRD_ANON,
@@ -157,11 +165,15 @@
} else if (object_dynamic_cast(OBJECT(creds),
TYPE_QCRYPTO_TLS_CREDS_X509)) {
QCryptoTLSCredsX509 *tcreds = QCRYPTO_TLS_CREDS_X509(creds);
+ const char *prio = creds->priority;
+ if (!prio) {
+ prio = "NORMAL";
+ }
- ret = gnutls_set_default_priority(session->handle);
+ ret = gnutls_priority_set_direct(session->handle, prio, NULL);
if (ret < 0) {
- error_setg(errp, "Cannot set default TLS session priority: %s",
- gnutls_strerror(ret));
+ error_setg(errp, "Cannot set default TLS session priority %s: %s",
+ prio, gnutls_strerror(ret));
goto error;
}
ret = gnutls_credentials_set(session->handle,
