mei: bus: type promotion bug in mei_nfc_if_version()

commit b40b3e9 upstream.

We accidentally removed the check for negative returns
without considering the issue of type promotion.
The "if_version_length" variable is type size_t so if __mei_cl_recv()
returns a negative then "bytes_recv" is type promoted
to a high positive value and treated as success.

Fixes: 582ab27 ("mei: bus: fix received data size check in NFC fixup")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/misc/mei/nfc.c

@@ -292,7 +292,7 @@ static int mei_nfc_if_version(struct mei_nfc_dev *ndev)
  return -ENOMEM;
 
  bytes_recv = __mei_cl_recv(cl, (u8 *)reply, if_version_length);
- if (bytes_recv < if_version_length) {
+ if (bytes_recv < 0 || bytes_recv < if_version_length) {
  dev_err(&dev->pdev->dev, "Could not read IF version\n");
  ret = -EIO;
  goto err;