[PATCH v2 03/27] qemuDomainMasterKeyCreate: Don't use VIR_DISPOSE_N on failure

[Peter Krempa <pkrempa@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 src/qemu/qemu_domain.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 0c078a9388..2c34307c82 100644
--- 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;
 }
-- 
2.29.2