[Libguestfs] [nbdkit PATCH 2/5] protocol: Validate request flags

[Eric Blake]

Reject rather than silently ignoring unknown client request flags.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 src/connections.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/connections.c b/src/connections.c
index 16c6584..44b7530 100644
--- a/src/connections.c
+++ b/src/connections.c
@@ -546,6 +546,13 @@ validate_request (struct connection *conn,
     return 0;
   }

+  /* Validate flags */
+  if (flags & ~NBD_CMD_FLAG_FUA) {
+    nbdkit_error ("invalid request: unknown flag (0x%x)", flags);
+    *error = EINVAL;
+    return 0;
+  }
+
   /* Refuse over-large read and write requests. */
   if ((cmd == NBD_CMD_WRITE || cmd == NBD_CMD_READ) &&
       count > MAX_REQUEST_SIZE) {
@@ -741,7 +748,7 @@ recv_request_send_reply (struct connection *conn)
   }

   cmd = be32toh (request.type);
-  flags = cmd;
+  flags = cmd & ~NBD_CMD_MASK_COMMAND;
   cmd &= NBD_CMD_MASK_COMMAND;

   offset = be64toh (request.offset);
-- 
2.9.3