Commit 56a82992 authored by Johan Hovold's avatar Johan Hovold Committed by Ben Hutchings

USB: serial: mct_u232: fix modem-status error handling

commit 36356a66 upstream.

Make sure to detect short control-message transfers so that errors are
logged when reading the modem status at open.

Note that while this also avoids initialising the modem status using
uninitialised heap data, these bits could not leak to user space as they
are currently not used.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 9742f545
...@@ -385,9 +385,13 @@ static int mct_u232_get_modem_stat(struct usb_serial *serial, ...@@ -385,9 +385,13 @@ static int mct_u232_get_modem_stat(struct usb_serial *serial,
MCT_U232_GET_REQUEST_TYPE, MCT_U232_GET_REQUEST_TYPE,
0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE, 0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE,
WDR_TIMEOUT); WDR_TIMEOUT);
if (rc < 0) { if (rc < MCT_U232_GET_MODEM_STAT_SIZE) {
dev_err(&serial->dev->dev, dev_err(&serial->dev->dev,
"Get MODEM STATus failed (error = %d)\n", rc); "Get MODEM STATus failed (error = %d)\n", rc);
if (rc >= 0)
rc = -EIO;
*msr = 0; *msr = 0;
} else { } else {
*msr = buf[0]; *msr = buf[0];
......
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