[PATCH 2/2] ipc: freebsd: NULL out some freed memory in kernel_set_device()

[kevans@FreeBSD.org]

From: Kyle Evans <kevans@FreeBSD.org>

The `err` path in kernel_set_device() will attempt to free() allocated
nvl_peers, but these two cases meant we could end up attempting a use
after free or a double free, as we rely on nvlist_destroy(NULL) being
a NOP as well as free(NULL).

FreeBSD-Coverity:	1500421
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
---
 src/ipc-freebsd.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/ipc-freebsd.h b/src/ipc-freebsd.h
index 78064e9..f9d3550 100644
--- a/src/ipc-freebsd.h
+++ b/src/ipc-freebsd.h
@@ -333,6 +333,7 @@ static int kernel_set_device(struct wgdevice *dev)
 			nvlist_destroy(nvl_aips[j]);
 		free(nvl_aips);
 		nvlist_destroy(nvl_peers[i]);
+		nvl_peers[i] = NULL;
 		goto err;
 	}
 	if (i) {
@@ -340,9 +341,11 @@ static int kernel_set_device(struct wgdevice *dev)
 		for (i = 0; i < peer_count; ++i)
 			nvlist_destroy(nvl_peers[i]);
 		free(nvl_peers);
+		nvl_peers = NULL;
 	}
 	wgd.wgd_data = nvlist_pack(nvl_device, &wgd.wgd_size);
 	nvlist_destroy(nvl_device);
+	nvl_device = NULL;
 	if (!wgd.wgd_data)
 		goto err;
 	s = get_dgram_socket();
-- 
2.36.1