Commit b9258a2c authored Apr 01, 2020 by Richard Palethorpe Committed by David S. Miller Apr 01, 2020

slcan: Don't transmit uninitialized stack data in padding



struct can_frame contains some padding which is not explicitly zeroed in
slc_bump. This uninitialized data will then be transmitted if the stack
initialization hardening feature is not enabled (CONFIG_INIT_STACK_ALL).

This commit just zeroes the whole struct including the padding.

Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Fixes: a1044e36 ("can: add slcan driver for serial/USB-serial CAN adapters")
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: security@kernel.org
Cc: wg@grandegger.com
Cc: mkl@pengutronix.de
Cc: davem@davemloft.net
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b1f4c209

drivers/net/can/slcan.c

+1 −3

Original line number	Original line	Diff line number	Diff line
	@@ -148,7 +148,7 @@ static void slc_bump(struct slcan *sl)
	u32 tmpid;		u32 tmpid;
	char *cmd = sl->rbuff;		char *cmd = sl->rbuff;

	cf.can_id = 0;		memset(&cf, 0, sizeof(cf));

	switch (*cmd) {		switch (*cmd) {
	case 'r':		case 'r':
	@@ -187,8 +187,6 @@ static void slc_bump(struct slcan *sl)
	else		else
	return;		return;

	(u64 ) (&cf.data) = 0; /* clear payload */

	/* RTR frames may have a dlc > 0 but they never have any data bytes */		/* RTR frames may have a dlc > 0 but they never have any data bytes */
	if (!(cf.can_id & CAN_RTR_FLAG)) {		if (!(cf.can_id & CAN_RTR_FLAG)) {
	for (i = 0; i < cf.can_dlc; i++) {		for (i = 0; i < cf.can_dlc; i++) {

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