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cdc-acm: fix possible invalid access when processing notification

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Notifications may only be 8 bytes long. Accessing the 9th and
10th byte of unimplemented/unknown notifications may be insecure.
Also check the length of known notifications before accessing anything
behind the 8th byte.

Signed-off-by: Tobias Herzog <t-herzog@gmx.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tobias Herzog 2017-03-30 22:15:10 +02:00 committed by Greg Kroah-Hartman
parent 2f86a96be0
commit 1bb9914e17
1 changed files with 9 additions and 4 deletions
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13
drivers/usb/class/cdc-acm.c
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@ -323,6 +323,12 @@ static void acm_ctrl_irq(struct urb *urb)
break;
case USB_CDC_NOTIFY_SERIAL_STATE:
if (le16_to_cpu(dr->wLength) != 2) {
dev_dbg(&acm->control->dev,
"%s - malformed serial state\n", __func__);
break;
}
newctrl = get_unaligned_le16(data);
if (!acm->clocal && (acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
@ -359,11 +365,10 @@ static void acm_ctrl_irq(struct urb *urb)
default:
dev_dbg(&acm->control->dev,
"%s - unknown notification %d received: index %d "
"len %d data0 %d data1 %d\n",
"%s - unknown notification %d received: index %d len %d\n",
__func__,
dr->bNotificationType, dr->wIndex,
dr->wLength, data[0], data[1]);
dr->bNotificationType, dr->wIndex, dr->wLength);
break;
}
exit: