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  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:	Sat, 25 May 2013 09:05:25 +0200
From:	Paolo Bonzini <>
To:	Christoph Hellwig <>
CC:	James Bottomley <>,
	Tejun Heo <>, Jens Axboe <>,
	lkml <>,
	"" <>
Subject: Re: PING^7 (was Re: [PATCH v2 00/14] Corrections and customization
 of the SG_IO command whitelist (CVE-2012-4542))

Il 25/05/2013 07:27, Christoph Hellwig ha scritto:
> On Fri, May 24, 2013 at 09:35:02PM -0700, James Bottomley wrote:
>> I'll go along with this.  I'm also wondering what the problem would be
>> if we just allowed all commands on either CAP_SYS_RAWIO or opening the
>> device for write, so we just defer to the filesystem permissions and
>> restricted read only opens to the basic all device opcodes.
> I've been out of this area for a bit, but the problem used to be that
> you could send destructive commands to a partition.  The right fix
> for that would be to not allow SG_IO on partitions at all, just
> wondering if anything would be broken by this.

Linus wanted to keep that for CAP_SYS_RAWIO.  We found two uses of SG_IO
on partitions: zfs-fuse used SYNCHRONIZE CACHE; some proprietary driver

Really, the solution is to make the bitmaps configurable in userspace.
It is no less secure than unpriv_sgio.  Then the kernel can be
configured at build-time to have either an MMC bitmap and a basic
whitelist of a dozen commands.  We can even avoid working around those
few conflicting opcodes; if you're paranoid you can just configure your
kernel right.

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