From: Michal Privoznik <mprivozn@redhat.com>
Date: Thu, 7 Sep 2023 08:56:01 +0000 (+0200)
Subject: virsh-snapshot: Avoid passing NULL to qsort() in virshSnapshotListCollect()
X-Git-Tag: v9.8.0-rc1~144
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=67c93cfae9312160de840d309bb3f5c36e5c9e9a;p=thirdparty%2Flibvirt.git

virsh-snapshot: Avoid passing NULL to qsort() in virshSnapshotListCollect()

If a domain has no snapshots and 'virsh snapshot-list' is called,
this gets all the way down to virshSnapshotListCollect() which
then collects all snapshots (none), and passes them to qsort()
which doesn't like being called with NULL:

  extern void qsort (void *__base, size_t __nmemb, size_t __size,
                     __compar_fn_t __compar) __nonnull ((1, 4));

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/533
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---

diff --git a/tools/virsh-snapshot.c b/tools/virsh-snapshot.c
index d7889a38e4..c85258c09a 100644
--- a/tools/virsh-snapshot.c
+++ b/tools/virsh-snapshot.c
@@ -1310,9 +1310,11 @@ virshSnapshotListCollect(vshControl *ctl, virDomainPtr dom,
             }
         }
     }
-    if (!(orig_flags & VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL))
+    if (!(orig_flags & VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL) &&
+        snaplist->snaps && snaplist->nsnaps) {
         qsort(snaplist->snaps, snaplist->nsnaps, sizeof(*snaplist->snaps),
               virshSnapSorter);
+    }
     snaplist->nsnaps -= deleted;
 
     ret = g_steal_pointer(&snaplist);