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From: ebiederm@xmission.com (Eric W. Biederman)
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: linux-kernel@vger.kernel.org, serge@hallyn.com, tycho@tycho.ws,
	Linux Containers <containers@lists.linux-foundation.org>
Subject: [PATCH 0/5] userns: bump idmap limits, fixes & tweaks
Date: Tue, 31 Oct 2017 18:46:32 -0500	[thread overview]
Message-ID: <871sliubhj.fsf_-_@xmission.com> (raw)
In-Reply-To: <20171024220441.10235-2-christian.brauner@ubuntu.com> (Christian Brauner's message of "Wed, 25 Oct 2017 00:04:41 +0200")


Christian I have looked through your code and I have found one real
issue and of things I want to twak

The real issue is reading nr_extents multiple times when reading a map.
That can introduce races that will allow walking past the end of the
array, if the first read is 0 but the second read is > 5.

I have also found a couple of tweaks that look like they are worth
implementing.

As all of these are very small and very straight forward I have
tested these and applied them all to my for-next branch


Eric W. Biederman (5):
      userns: Don't special case a count of 0
      userns: Simplify the user and group mapping functions
      userns: Don't read extents twice in m_start
      userns: Make map_id_down a wrapper for map_id_range_down
      userns: Simplify insert_extent

 kernel/user_namespace.c | 159 ++++++++++++++++--------------------------------
 1 file changed, 51 insertions(+), 108 deletions(-)

  parent reply	other threads:[~2017-10-31 23:46 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-24 22:04 [PATCH 1/2 v6] user namespace: use union in {g,u}idmap struct Christian Brauner
2017-10-24 22:04 ` [PATCH 2/2 v6] user namespaces: bump idmap limits to 340 Christian Brauner
     [not found]   ` <20171024220441.10235-2-christian.brauner-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>
2017-10-31 23:46     ` [PATCH 0/5] userns: bump idmap limits, fixes & tweaks Eric W. Biederman
2017-10-31 23:46   ` Eric W. Biederman [this message]
2017-10-31 23:47     ` [PATCH 1/5] userns: Don't special case a count of 0 Eric W. Biederman
2017-10-31 23:47     ` [PATCH 2/5] userns: Simplify the user and group mapping functions Eric W. Biederman
2017-10-31 23:48     ` [PATCH 3/5] userns: Don't read extents twice in m_start Eric W. Biederman
2017-11-01  8:31       ` Nikolay Borisov
2017-11-01 11:08         ` Eric W. Biederman
     [not found]           ` <87a806ntn0.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-11-01 13:05             ` Nikolay Borisov
2017-11-01 13:05             ` Peter Zijlstra
2017-11-01 17:00             ` Joe Perches
2017-11-01 13:05           ` Nikolay Borisov
2017-11-01 13:05           ` Peter Zijlstra
2017-11-01 16:31             ` Christian Brauner
     [not found]             ` <20171101130539.j5bxmhs2trqurrr2-Nxj+rRp3nVydTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2017-11-01 14:01               ` Christian Brauner
2017-11-01 14:01                 ` Christian Brauner
     [not found]                 ` <20171101140144.zwe7cq7iv2xudwp4-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-11-01 14:16                   ` Peter Zijlstra
2017-11-01 14:16                     ` Peter Zijlstra
     [not found]                     ` <20171101141654.fr4rs2m5cygouktb-Nxj+rRp3nVydTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2017-11-01 16:29                       ` Christian Brauner
2017-11-01 16:29                         ` Christian Brauner
2017-11-01 16:31               ` Christian Brauner
2017-11-01 17:00           ` Joe Perches
     [not found]             ` <1509555601.31043.44.camel-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
2017-11-01 17:20               ` Eric W. Biederman
2017-11-01 17:20             ` Eric W. Biederman
     [not found]               ` <87h8udj4p7.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-11-01 18:15                 ` Peter Zijlstra
2017-11-01 18:15                   ` Peter Zijlstra
     [not found]         ` <143adb61-fb8e-fc1b-396b-b18836e68766-IBi9RG/b67k@public.gmane.org>
2017-11-01 11:08           ` Eric W. Biederman
     [not found]       ` <87k1zaswu6.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-11-01  8:31         ` Nikolay Borisov
2017-10-31 23:48     ` [PATCH 4/5] userns: Make map_id_down a wrapper for map_id_range_down Eric W. Biederman
     [not found]     ` <871sliubhj.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-10-31 23:47       ` [PATCH 1/5] userns: Don't special case a count of 0 Eric W. Biederman
2017-10-31 23:47       ` [PATCH 2/5] userns: Simplify the user and group mapping functions Eric W. Biederman
2017-10-31 23:48       ` [PATCH 3/5] userns: Don't read extents twice in m_start Eric W. Biederman
2017-10-31 23:48       ` [PATCH 4/5] userns: Make map_id_down a wrapper for map_id_range_down Eric W. Biederman
2017-10-31 23:49       ` [PATCH 5/5] userns: Simplify insert_extent Eric W. Biederman
2017-11-01 10:51       ` [PATCH 0/5] userns: bump idmap limits, fixes & tweaks Christian Brauner
2017-10-31 23:49     ` [PATCH 5/5] userns: Simplify insert_extent Eric W. Biederman
2017-11-01 10:51     ` [PATCH 0/5] userns: bump idmap limits, fixes & tweaks Christian Brauner
2017-11-01 11:15       ` Eric W. Biederman
     [not found]         ` <87tvyemeqe.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-11-01 13:31           ` Christian Brauner
2017-11-01 13:31             ` Christian Brauner
     [not found]       ` <CAPP7u0WDVv0pAAFEuzL2c9Y-wVg0xG36jyH-eok=GV-r6UewZg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-11-01 11:15         ` Eric W. Biederman

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