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* [PATCH] can: bcm: fix infoleak in struct bcm_msg_head
@ 2021-06-12 21:09 Norbert Slusarek
  2021-06-13  9:51 ` Oliver Hartkopp
  2021-06-14  7:20 ` Marc Kleine-Budde
  0 siblings, 2 replies; 8+ messages in thread
From: Norbert Slusarek @ 2021-06-12 21:09 UTC (permalink / raw)
  To: socketcan; +Cc: mkl, davem, kuba, linux-can, netdev

From: Norbert Slusarek <nslusarek@gmx.net>
Date: Sat, 12 Jun 2021 22:18:54 +0200
Subject: [PATCH] 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: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol")
Signed-off-by: Norbert Slusarek <nslusarek@gmx.net>

---
 net/can/bcm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 909b9e684e04..b03062f84fe7 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -402,6 +402,7 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
                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 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;
@@ -560,6 +562,7 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
        }

        /* 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

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-06-15 20:40 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-12 21:09 [PATCH] can: bcm: fix infoleak in struct bcm_msg_head Norbert Slusarek
2021-06-13  9:51 ` Oliver Hartkopp
2021-06-13 11:18   ` Patrick Menschel
2021-06-13 13:35     ` Norbert Slusarek
2021-06-13 15:36       ` Patrick Menschel
2021-06-13 18:33         ` Norbert Slusarek
2021-06-14  7:20 ` Marc Kleine-Budde
2021-06-15 20:40   ` Norbert Slusarek

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