[PATCH 4.4 31/57] can: bcm: fix infoleak in struct bcm_msg_head
From: Sasha Levin <sashal@kernel.org>
Date: 2021-06-28 15:28:35
Also in:
lkml
Subsystem:
can network layer, the rest · Maintainers:
Oliver Hartkopp, Marc Kleine-Budde, Linus Torvalds
From: Norbert Slusarek <redacted>
commit 5e87ddbe3942e27e939bdc02deb8579b0cbd8ecc upstream.
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-1623532166177@3c-app-gmx-bs52 (local)
Cc: linux-stable <redacted>
Signed-off-by: Norbert Slusarek <redacted>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/can/bcm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 1f15622d3c65..bd9e10db6cd7 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c@@ -392,6 +392,7 @@ 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;
@@ -439,6 +440,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct can_frame *data) /* this element is not throttled anymore */ data->can_dlc &= (BCM_CAN_DLC_MASK|RX_RECV); + memset(&head, 0, sizeof(head)); head.opcode = RX_CHANGED; head.flags = op->flags; head.count = op->count;
@@ -550,6 +552,7 @@ 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;
--
2.30.2