mei: bus: type promotion bug in mei_fwver()

if __mei_cl_recv() returns a negative then "bytes_recv"
type is promoted to a high positive value in comparison with
size_t evaluated by MKHI_FWVER_LEN(1). It results in error condition
not to be detected.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 9078ad92ef86 ("mei: expose fw version to sysfs")
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/bus-fixup.c b/drivers/misc/mei/bus-fixup.c
index 65e28be3c8cc4d224ff892cf82ba8a30d649094b..4c232f0eae90425fe510a91317287581faf6c011 100644 (file)
--- a/drivers/misc/mei/bus-fixup.c
+++ b/drivers/misc/mei/bus-fixup.c
@@ -181,7 +181,7 @@ static int mei_fwver(struct mei_cl_device *cldev)
        ret = 0;
        bytes_recv = __mei_cl_recv(cldev->cl, buf, sizeof(buf), 0,
                                   MKHI_RCV_TIMEOUT);
-       if (bytes_recv < MKHI_FWVER_LEN(1)) {
+       if (bytes_recv < 0 || bytes_recv < MKHI_FWVER_LEN(1)) {
                /*
                 * Should be at least one version block,
                 * error out if nothing found