On a Friday in 2022, Peter Krempa wrote:
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@xxxxxxxxxx>
---
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;
Is this necessary? In the case 'alias' will be assigned a value,
we will steal the value right away.
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;
- }
Reviewed-by: Ján Tomko <jtomko@xxxxxxxxxx>
Jano
