archive mirror
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <>
To: Ondrej Mosnacek <>
Cc:, David Howells <>,
	Matthew Garrett <>,
	Kees Cook <>,
	Jiri Slaby <>,,,
	James Morris <>,,
Subject: Re: [PATCH] serial: core: fix suspicious security_locked_down() call
Date: Fri, 7 May 2021 14:27:17 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Fri, May 07, 2021 at 01:57:19PM +0200, Ondrej Mosnacek wrote:
> The commit that added this check did so in a very strange way - first
> security_locked_down() is called, its value stored into retval, and if
> it's nonzero, then an additional check is made for (change_irq ||
> change_port), and if this is true, the function returns. However, if
> the goto exit branch is not taken, the code keeps the retval value and
> continues executing the function. Then, depending on whether
> uport->ops->verify_port is set, the retval value may or may not be reset
> to zero and eventually the error value from security_locked_down() may
> abort the function a few lines below.
> I will go out on a limb and assume that this isn't the intended behavior
> and that an error value from security_locked_down() was supposed to
> abort the function only in case (change_irq || change_port) is true.

Are you _sure_ about this?

Verification from the authors and users of this odd feature might be
good to have, as I am loath to change how this works without them
weighing in here.


greg k-h

  reply	other threads:[~2021-05-07 12:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-07 11:57 [PATCH] serial: core: fix suspicious security_locked_down() call Ondrej Mosnacek
2021-05-07 12:27 ` Greg Kroah-Hartman [this message]
2021-05-07 12:58   ` Ondrej Mosnacek
2021-05-10 19:36 ` Kees Cook

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 \ \ \ \ \ \ \ \ \ \ \ \ \ \

* 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).