From: Himadri Pandya <himadrispandya@gmail.com>
Date: Thu, 27 Aug 2020 06:53:55 +0000 (+0530)
Subject: net: usb: Fix uninit-was-stored issue in asix_read_phy_addr()
X-Git-Tag: v4.4.236~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a5455cd886649e3bd39b0fbf93b0cd0e45d05cb;p=thirdparty%2Fkernel%2Fstable.git

net: usb: Fix uninit-was-stored issue in asix_read_phy_addr()

commit a092b7233f0e000cc6f2c71a49e2ecc6f917a5fc upstream.

The buffer size is 2 Bytes and we expect to receive the same amount of
data. But sometimes we receive less data and run into uninit-was-stored
issue upon read. Hence modify the error check on the return value to match
with the buffer size as a prevention.

Reported-and-tested by: syzbot+a7e220df5a81d1ab400e@syzkaller.appspotmail.com
Signed-off-by: Himadri Pandya <himadrispandya@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 2092ef6431f20..712765976a221 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -251,7 +251,7 @@ int asix_read_phy_addr(struct usbnet *dev, int internal)
 
 	netdev_dbg(dev->net, "asix_get_phy_addr()\n");
 
-	if (ret < 0) {
+	if (ret < 2) {
 		netdev_err(dev->net, "Error reading PHYID register: %02x\n", ret);
 		goto out;
 	}