Commit 5e87ddbe authored by Norbert Slusarek's avatar Norbert Slusarek Committed by Marc Kleine-Budde
Browse files

can: bcm: fix infoleak in struct bcm_msg_head 

On 64-bit systems, struct bcm_msg_head has an added padding of 4 bytes between
struct members count and ival1. Even though all struct members are initialized,
the 4-byte hole will contain data from the kernel stack. This patch zeroes out
struct bcm_msg_head before usage, preventing infoleaks to userspace.

Fixes: ffd980f9 ("[CAN]: Add broadcast manager (bcm) protocol")
Link: https://lore.kernel.org/r/trinity-7c1b2e82-e34f-4885-8060-2cd7a13769ce-1623532166177@3c-app-gmx-bs52


Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: default avatarNorbert Slusarek <nslusarek@gmx.net>
Acked-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 8d0caedb

net/can/bcm.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -406,6 +406,7 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer) 
		if (!op->count && (op->flags & TX_COUNTEVT)) {

		if (!op->count && (op->flags & TX_COUNTEVT)) {





			/* create notification to user */

			/* create notification to user */

			memset(&msg_head, 0, sizeof(msg_head));

			msg_head.opcode  = TX_EXPIRED;

			msg_head.opcode  = TX_EXPIRED;

			msg_head.flags   = op->flags;

			msg_head.flags   = op->flags;

			msg_head.count   = op->count;

			msg_head.count   = op->count;
@@ -443,6 +444,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data) 
	/* this element is not throttled anymore */

	/* this element is not throttled anymore */

	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);

	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);





	memset(&head, 0, sizeof(head));

	head.opcode  = RX_CHANGED;

	head.opcode  = RX_CHANGED;

	head.flags   = op->flags;

	head.flags   = op->flags;

	head.count   = op->count;

	head.count   = op->count;
@@ -564,6 +566,7 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer) 
	}

	}





	/* create notification to user */

	/* create notification to user */

	memset(&msg_head, 0, sizeof(msg_head));

	msg_head.opcode  = RX_TIMEOUT;

	msg_head.opcode  = RX_TIMEOUT;

	msg_head.flags   = op->flags;

	msg_head.flags   = op->flags;

	msg_head.count   = op->count;

	msg_head.count   = op->count;