qemuDomainMasterKeyCreate: Don't use VIR_DISPOSE_N on failure

When virRandomBytes fails we don't get any random bytes and even if we
did they don't have to be treated as secret as they weren't used in any
way.

Add a temporary variable with automatic freeing for the secret buffer
and assign it only on success.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 0c078a9388fd7bd3d16b0d858a8fc2366c580e2d..2c34307c823c956f5e52bc362124ae20b84fe164 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -562,18 +562,19 @@ int
 qemuDomainMasterKeyCreate(virDomainObjPtr vm)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
+    g_autofree uint8_t *key = NULL;
 
     /* If we don't have the capability, then do nothing. */
     if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_OBJECT_SECRET))
         return 0;
 
-    priv->masterKey = g_new0(uint8_t, QEMU_DOMAIN_MASTER_KEY_LEN);
-    priv->masterKeyLen = QEMU_DOMAIN_MASTER_KEY_LEN;
+    key = g_new0(uint8_t, QEMU_DOMAIN_MASTER_KEY_LEN);
 
-    if (virRandomBytes(priv->masterKey, priv->masterKeyLen) < 0) {
-        VIR_DISPOSE_N(priv->masterKey, priv->masterKeyLen);
+    if (virRandomBytes(key, QEMU_DOMAIN_MASTER_KEY_LEN) < 0)
         return -1;
-    }
+
+    priv->masterKey = g_steal_pointer(&key);
+    priv->masterKeyLen = QEMU_DOMAIN_MASTER_KEY_LEN;
 
     return 0;
 }