From: Norbert Slusarek nslusarek@gmx.net
mainline inclusion from mainline-v5.13-rc7 commit 5e87ddbe3942e27e939bdc02deb8579b0cbd8ecc category: bugfix bugzilla: NA CVE: CVE-2021-34693
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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: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Link: https://lore.kernel.org/r/trinity-7c1b2e82-e34f-4885-8060-2cd7a13769ce-16235... Cc: linux-stable stable@vger.kernel.org Signed-off-by: Norbert Slusarek nslusarek@gmx.net Acked-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/can/bcm.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/can/bcm.c b/net/can/bcm.c index f5f97d9c17d20..0f09838ebef6e 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -393,6 +393,7 @@ static void bcm_tx_timeout_tsklet(unsigned long data) if (!op->count && (op->flags & TX_COUNTEVT)) {
/* create notification to user */ + memset(&msg_head, 0, sizeof(msg_head)); msg_head.opcode = TX_EXPIRED; msg_head.flags = op->flags; msg_head.count = op->count; @@ -440,6 +441,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data) /* this element is not throttled anymore */ data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
+ memset(&head, 0, sizeof(head)); head.opcode = RX_CHANGED; head.flags = op->flags; head.count = op->count; @@ -554,6 +556,7 @@ static void bcm_rx_timeout_tsklet(unsigned long data) struct bcm_msg_head msg_head;
/* create notification to user */ + memset(&msg_head, 0, sizeof(msg_head)); msg_head.opcode = RX_TIMEOUT; msg_head.flags = op->flags; msg_head.count = op->count;