netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Norbert Slusarek <nslusarek@gmx.net>
To: socketcan@hartkopp.net
Cc: mkl@pengutronix.de, davem@davemloft.net, kuba@kernel.org,
	linux-can@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH] can: bcm: fix infoleak in struct bcm_msg_head
Date: Sat, 12 Jun 2021 23:09:26 +0200	[thread overview]
Message-ID: <trinity-7c1b2e82-e34f-4885-8060-2cd7a13769ce-1623532166177@3c-app-gmx-bs52> (raw)

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

             reply	other threads:[~2021-06-12 21:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-12 21:09 Norbert Slusarek [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=trinity-7c1b2e82-e34f-4885-8060-2cd7a13769ce-1623532166177@3c-app-gmx-bs52 \
    --to=nslusarek@gmx.net \
    --cc=davem@davemloft.net \
    --cc=kuba@kernel.org \
    --cc=linux-can@vger.kernel.org \
    --cc=mkl@pengutronix.de \
    --cc=netdev@vger.kernel.org \
    --cc=socketcan@hartkopp.net \
    --subject='Re: [PATCH] can: bcm: fix infoleak in struct bcm_msg_head' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).