Re: [PATCH v2 4/4] block/export: avoid g_return_val_if() input validation

[Marc-André Lureau]

On Wed, Dec 2, 2020 at 7:27 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:

Do not validate input with g_return_val_if(). This API is intended for
checking programming errors and is compiled out with -DG_DISABLE_CHECKS.

Use an explicit if statement for input validation so it cannot
accidentally be compiled out.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> 

---
 block/export/vhost-user-blk-server.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index 62672d1cb9..bccbc98d57 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -267,7 +267,11 @@ vu_blk_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
     VuServer *server = container_of(vu_dev, VuServer, vu_dev);
     VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);

-    g_return_val_if_fail(len <= sizeof(struct virtio_blk_config), -1);
+    if (len > sizeof(struct virtio_blk_config)) {
+        error_report("Invalid get_config len %u, expected <= %zu",
+                     len, sizeof(struct virtio_blk_config));
+        return -1;
+    }

     memcpy(config, &vexp->blkcfg, len);
     return 0;
--
2.28.0

--

Marc-André Lureau