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:   Mon, 17 Feb 2020 13:06:08 -0800
From:   James Bottomley <>
To:     Christian Brauner <>,
        St├ęphane Graber <>,
        "Eric W. Biederman" <>,
        Aleksa Sarai <>, Jann Horn <>
Cc:     Kees Cook <>,
        Jonathan Corbet <>,,,,
        Seth Forshee <>,,
        Alexander Viro <>,,,
        Alexey Dobriyan <>
Subject: Re: [PATCH v2 00/28] user_namespace: introduce fsid mappings

On Fri, 2020-02-14 at 19:35 +0100, Christian Brauner wrote:
> People not as familiar with user namespaces might not be aware that
> fsid mappings already exist. Right now, fsid mappings are always
> identical to id mappings. Specifically, the kernel will lookup fsuids
> in the uid mappings and fsgids in the gid mappings of the relevant
> user namespace.

This isn't actually entirely true: today we have the superblock user
namespace, which can be used for fsid remapping on filesystems that
support it (currently f2fs and fuse).  Since this is a single shift,
how is it going to play with s_user_ns?  Do you have to understand the
superblock mapping to use this shift, or are we simply using this to
replace s_user_ns?


Powered by blists - more mailing lists