From 1bb9914e1730417d530de9ed37e59efdc647146b Mon Sep 17 00:00:00 2001 From: Tobias Herzog Date: Thu, 30 Mar 2017 22:15:10 +0200 Subject: cdc-acm: fix possible invalid access when processing notification 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 Acked-by: Oliver Neukum Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'drivers/usb/class/cdc-acm.c') diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 00d55ba8983f..cdabe76960bc 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -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: -- cgit v1.2.3