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Commit | Line | Data |
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857a8367 GKH |
1 | From 36356a669eddb32917fc4b5c2b9b8bf80ede69de Mon Sep 17 00:00:00 2001 |
2 | From: Johan Hovold <johan@kernel.org> | |
3 | Date: Thu, 12 Jan 2017 14:56:16 +0100 | |
4 | Subject: USB: serial: mct_u232: fix modem-status error handling | |
5 | ||
6 | From: Johan Hovold <johan@kernel.org> | |
7 | ||
8 | commit 36356a669eddb32917fc4b5c2b9b8bf80ede69de upstream. | |
9 | ||
10 | Make sure to detect short control-message transfers so that errors are | |
11 | logged when reading the modem status at open. | |
12 | ||
13 | Note that while this also avoids initialising the modem status using | |
14 | uninitialised heap data, these bits could not leak to user space as they | |
15 | are currently not used. | |
16 | ||
17 | Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") | |
18 | Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
19 | Signed-off-by: Johan Hovold <johan@kernel.org> | |
20 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
21 | ||
22 | --- | |
23 | drivers/usb/serial/mct_u232.c | 6 +++++- | |
24 | 1 file changed, 5 insertions(+), 1 deletion(-) | |
25 | ||
26 | --- a/drivers/usb/serial/mct_u232.c | |
27 | +++ b/drivers/usb/serial/mct_u232.c | |
28 | @@ -322,8 +322,12 @@ static int mct_u232_get_modem_stat(struc | |
29 | MCT_U232_GET_REQUEST_TYPE, | |
30 | 0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE, | |
31 | WDR_TIMEOUT); | |
32 | - if (rc < 0) { | |
33 | + if (rc < MCT_U232_GET_MODEM_STAT_SIZE) { | |
34 | dev_err(&port->dev, "Get MODEM STATus failed (error = %d)\n", rc); | |
35 | + | |
36 | + if (rc >= 0) | |
37 | + rc = -EIO; | |
38 | + | |
39 | *msr = 0; | |
40 | } else { | |
41 | *msr = buf[0]; |