[PATCH v2 1/9] virConnectOpenInternal: Avoid double free() when alias is an invalid URI

[Peter Krempa]

Configuring an URI alias such as

  uri_aliases = [
      "blah=qemu://invaliduri@@@",
  ]

Results in a double free when the alias is used:

  $ virsh -c blah
  free(): double free detected in tcache 2
  Aborted (core dumped)

This happens as the 'alias' variable is first assigned to 'uristr' which
is cleared in the 'failed' label and then is explicitly freed again.

Fix this by switching to 'g_autofree' for alias and stealing it into
'uristr'.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/libvirt.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/libvirt.c b/src/libvirt.c
index b78b49a632..7e7c0fc8e3 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -933,21 +933,19 @@ virConnectOpenInternal(const char *name,
     }

     if (uristr) {
-        char *alias = NULL;
+        g_autofree char *alias = NULL;

         if (!(flags & VIR_CONNECT_NO_ALIASES) &&
             virURIResolveAlias(conf, uristr, &alias) < 0)
             goto failed;

         if (alias) {
-            VIR_FREE(uristr);
-            uristr = alias;
+            g_free(uristr);
+            uristr = g_steal_pointer(&alias);
         }

-        if (!(ret->uri = virURIParse(uristr))) {
-            VIR_FREE(alias);
+        if (!(ret->uri = virURIParse(uristr)))
             goto failed;
-        }

         /* Avoid need for drivers to worry about NULLs, as
          * no one needs to distinguish "" vs NULL */
-- 
2.37.1