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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: 2015 kernel CVEs
Date: Tue, 19 Jan 2016 18:00:09 +0000	[thread overview]
Message-ID: <20160119180009.GT17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20160119112812.GA10818@mwanda>

On Tue, Jan 19, 2016 at 02:28:12PM +0300, Dan Carpenter wrote:
> CVE-2015-4178 820f9f147dcc: fs_pin: uninitialized data

Why is that a CVE?  Affected code is in pin_remove(), which is only
called from fs_pin ->kill() instances; if one is _ever_ called more
than once per fs_pin lifetime, we are already FUBAR.  If Eric had
ever intended to add checks for hlist_unhashed() on those lists,
such checks never had been added to the tree.  They definitely did not
exist at the moment when that commit went in.

It got merged mostly on the "it doesn't harm anything and it's a bit
more tidy that way" basis; if it had ever changed behaviour in any visible
way, *THEN* we had a real problem and that problem was not fixed by that
commit, so I would really like to see the details - simply to make sure
that the damn thing had been eventually fixed.

Eric, could you explain?  And could whoever'd been responsible for
that CVE describe the process that had lead to its creation?

WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [kernel-hardening] Re: 2015 kernel CVEs
Date: Tue, 19 Jan 2016 18:00:09 +0000	[thread overview]
Message-ID: <20160119180009.GT17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20160119112812.GA10818@mwanda>

On Tue, Jan 19, 2016 at 02:28:12PM +0300, Dan Carpenter wrote:
> CVE-2015-4178 820f9f147dcc: fs_pin: uninitialized data

Why is that a CVE?  Affected code is in pin_remove(), which is only
called from fs_pin ->kill() instances; if one is _ever_ called more
than once per fs_pin lifetime, we are already FUBAR.  If Eric had
ever intended to add checks for hlist_unhashed() on those lists,
such checks never had been added to the tree.  They definitely did not
exist at the moment when that commit went in.

It got merged mostly on the "it doesn't harm anything and it's a bit
more tidy that way" basis; if it had ever changed behaviour in any visible
way, *THEN* we had a real problem and that problem was not fixed by that
commit, so I would really like to see the details - simply to make sure
that the damn thing had been eventually fixed.

Eric, could you explain?  And could whoever'd been responsible for
that CVE describe the process that had lead to its creation?

  parent reply	other threads:[~2016-01-19 18:00 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-19 11:28 2015 kernel CVEs Dan Carpenter
2016-01-19 11:28 ` [kernel-hardening] " Dan Carpenter
2016-01-19 11:49 ` Hanno Böck
2016-01-19 15:49   ` Quentin Casasnovas
2016-01-20 11:19   ` Hanno Böck
2016-01-20 14:15     ` Wade Mealing
2016-01-20 17:48       ` Hanno Böck
2016-01-19 13:13 ` Wade Mealing
2016-01-19 14:56 ` One Thousand Gnomes
2016-01-19 14:56   ` [kernel-hardening] " One Thousand Gnomes
2016-01-19 16:32 ` [kernel-hardening] " Ben Hutchings
2016-01-19 17:54   ` Greg KH
2016-01-20 17:05     ` Ben Hutchings
2016-01-20 18:04       ` Greg KH
2016-01-21 15:18         ` Jiri Kosina
2016-01-21 18:46         ` Ben Hutchings
2016-01-19 16:57 ` Peter Hurley
2016-01-19 16:57   ` [kernel-hardening] " Peter Hurley
2016-01-19 17:00   ` Josh Boyer
2016-01-19 17:00     ` [kernel-hardening] " Josh Boyer
2016-01-19 17:51     ` Greg KH
2016-01-19 17:51       ` [kernel-hardening] " Greg KH
2016-01-20  7:12       ` Marcus Meissner
2016-01-19 17:57 ` [kernel-hardening] " Theodore Ts'o
2016-01-19 18:00 ` Al Viro [this message]
2016-01-19 18:00   ` [kernel-hardening] " Al Viro
2016-01-19 22:41   ` Eric W. Biederman
2016-01-19 22:47 ` [kernel-hardening] " Eric W. Biederman
2016-01-20 20:11   ` Jann Horn
2016-01-20 21:26     ` One Thousand Gnomes
2016-01-19 23:35 ` Kees Cook
2016-01-19 23:35   ` Kees Cook
2016-01-20  9:57 ` Miroslav Benes
2016-01-20  9:57   ` [kernel-hardening] " Miroslav Benes

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