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 e9fcf6ef716a8d0f09d2e08c10e3e2bd4305098e..9bf18127e63a1a6c75e48c693154fb02d82ccc6c 100644 (file)
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -309,7 +309,7 @@ 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;
        }