[PATCH 3.16 036/328] mei: bus: type promotion bug in mei_nfc_if_version()

Ben Hutchings
2018-12-09T22:15:24Z

From: Dan Carpenter <dan.carpenter@oracle.com>

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.

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>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/misc/mei/nfc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/misc/mei/nfc.c
+++ b/drivers/misc/mei/nfc.c
@@ -292,7 +292,7 @@ static int mei_nfc_if_version(struct mei
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;