lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 20 Mar 2014 16:12:54 +0100
From:	David Herrmann <>
To:	One Thousand Gnomes <>
Cc:	Linus Torvalds <>,
	Linux Kernel Mailing List <>,
	Hugh Dickins <>,
	Alexander Viro <>,
	Karol Lewandowski <>,
	Kay Sievers <>, Daniel Mack <>,
	Lennart Poettering <>,
	Kristian Høgsberg <>,
	John Stultz <>,
	Greg Kroah-Hartman <>, Tejun Heo <>,
	Johannes Weiner <>,
	DRI <>,
	linux-fsdevel <>,
	linux-mm <>,
	Andrew Morton <>,
	Ryan Lortie <>,
	"Michael Kerrisk (man-pages)" <>
Subject: Re: [PATCH 0/6] File Sealing & memfd_create()


On Thu, Mar 20, 2014 at 3:41 PM, One Thousand Gnomes
<> wrote:
> I think you want two things at minimum
> owner to seal
> root can always override

Why should root be allowed to override?

> I would query the name too. Right now your assumption is 'shmem only' but
> that might change with other future use cases or types (eg some driver
> file handles) so SHMEM_ in the fcntl might become misleading.

I'm fine with F_SET/GET_SEALS. But given you suggested requiring
MFD_ALLOW_SEALS for sealing, I don't see why we couldn't limit this
interface entirely to memfd_create().

> Whether you want some way to undo a seal without an exclusive reference as
> the file owner is another question.

No. You are never allowed to undo a seal but with an exclusive
reference. This interface was created for situations _without_ any
trust relationship. So if the owner is allowed to undo seals, the
interface doesn't make any sense. The only options I see is to not
allow un-sealing at all (which I'm fine with) or tracking users (which
is way too much overhead).

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists