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authorEric Blake <eblake@redhat.com>2016-05-11 16:39:38 -0600
committerPaolo Bonzini <pbonzini@redhat.com>2016-06-16 18:39:05 +0200
commitab7c548e266a6324db0994cea58c35b3dc87bade (patch)
tree915e139e45abda56a92e0341a17f74900b2a8d28
parent29b6c3b319acb85b2f025bffebb8ed9b3a83602a (diff)
nbd: Reject unknown request flags
The NBD protocol says that clients should not send a command flag that has not been negotiated (whether by the client requesting an option during a handshake, or because we advertise support for the flag in response to NBD_OPT_EXPORT_NAME), and that servers should reject invalid flags with EINVAL. We were silently ignoring the flags instead. The client can't rely on our behavior, since it is their fault for passing the bad flag in the first place, but it's better to be robust up front than to possibly behave differently than the client was expecting with the attempted flag. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alex Bligh <alex@alex.org.uk> Message-Id: <1463006384-7734-6-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--nbd/server.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/nbd/server.c b/nbd/server.c
index 41388f5fe9..b0ca9d9771 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1072,6 +1072,11 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
rc = command == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
goto out;
}
+ if (request->type & ~NBD_CMD_MASK_COMMAND & ~NBD_CMD_FLAG_FUA) {
+ LOG("unsupported flags (got 0x%x)",
+ request->type & ~NBD_CMD_MASK_COMMAND);
+ return -EINVAL;
+ }
rc = 0;