qemuDomainDiskByName() can return a NULL pointer on failure, but this
returned value in qemuSnapshotDeleteValidate is not checked.
It will make libvirtd crash.
diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c
index 5b3aadcbf0..52312b4a7b 100644
--- a/src/qemu/qemu_snapshot.c
+++ b/src/qemu/qemu_snapshot.c
@@ -4235,8 +4235,11 @@ qemuSnapshotDeleteValidate(virDomainObj *vm,
virDomainDiskDef *vmdisk = NULL;
virDomainDiskDef *disk = NULL;
- vmdisk = qemuDomainDiskByName(vm->def, snapDisk->name);
- disk = qemuDomainDiskByName(snapdef->parent.dom,
snapDisk->name);
+ if (!(vmdisk = qemuDomainDiskByName(vm->def, snapDisk->name)))
+ return -1;
+
+ if (!(disk = qemuDomainDiskByName(snapdef->parent.dom,
snapDisk->name)))
+ return -1;
if (!virStorageSourceIsSameLocation(vmdisk->src, disk->src)) {
virReportError(VIR_ERR_OPERATION_UNSUPPORTED,