archive mirror
 help / color / mirror / Atom feed
From: Norbert Slusarek <>
To: Patrick Menschel <>
Cc: Oliver Hartkopp <>,,,,,
Subject: Re: [PATCH] can: bcm: fix infoleak in struct bcm_msg_head
Date: Sun, 13 Jun 2021 20:33:31 +0200	[thread overview]
Message-ID: <trinity-87eaea25-2a7d-4aa9-92a5-269b822e5d95-1623609211076@3c-app-gmx-bs04> (raw)
In-Reply-To: <>

>I should not skip lines while reading.
>We're talking about different gaps as it seems. I didn't realize the gap
>in front of ival1 before.
>There is also a gap in between nframes and frames[0].
>That one is caused by align(8) of data in struct can_frame.
>It propagates upwards into that gap on 32bit arch.
>You can find it if you actually fill frames[] with a frame.
>I found it while concatenating bcm_msg_head and a can frame into a
>python bytearray which was too short for the raspberry pi as I forgot
>the alignment.
>I came up with a format string "IIIllllII0q" for bcm_msg_head.
>Kind Regards,

I confirm that there is a similar 4-byte leak happening on 32-bit systems.
It's possible to retrieve kernel addresses etc. which allows for a KASLR
bypass. I will request a CVE and publish a notice regarding
this on oss-security where I will mention Patrick too.

Anyways, this patch seems to be working for the leak on 32-bit systems as well.


  reply	other threads:[~2021-06-13 18:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
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:

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

  git send-email \
    --in-reply-to=trinity-87eaea25-2a7d-4aa9-92a5-269b822e5d95-1623609211076@3c-app-gmx-bs04 \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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).