From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 11 Jul 2018 12:29:31 +0000 (+0300)
Subject: mei: bus: type promotion bug in mei_nfc_if_version()
X-Git-Tag: v4.4.158~3
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=24328b80de178d4ece8175481349ae33ba3ca65f;p=linux

mei: bus: type promotion bug in mei_nfc_if_version()

commit b40b3e9358fbafff6a4ba0f4b9658f6617146f9c 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.

Cc: <stable@vger.kernel.org>
Fixes: 582ab27a063a ("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>
---

diff --git a/drivers/misc/mei/bus-fixup.c b/drivers/misc/mei/bus-fixup.c
index bdc7fcd80eca..9dcdc6f41ceb 100644
--- a/drivers/misc/mei/bus-fixup.c
+++ b/drivers/misc/mei/bus-fixup.c
@@ -151,7 +151,7 @@ static int mei_nfc_if_version(struct mei_cl *cl,
 
 	ret = 0;
 	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(bus->dev, "Could not read IF version\n");
 		ret = -EIO;
 		goto err;