linux-kernel - Re: [PATCH] vfs,shmem,kernfs: fix listxattr to include security.* xattrs

lists.openwall.net		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 linux-cve-announce 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]

Message-ID: <CAEjxPJ5LGH_Vyf2KCL0HNwa-U70GVAOVvyFMnhpnzi-CEKvC5w@mail.gmail.com>
Date: Thu, 24 Apr 2025 09:53:36 -0400
From: Stephen Smalley <stephen.smalley.work@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: paul@...l-moore.com, omosnace@...hat.com, 
	linux-security-module@...r.kernel.org, selinux@...r.kernel.org, 
	Tejun Heo <tj@...nel.org>, Alexander Viro <viro@...iv.linux.org.uk>, 
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, Hugh Dickins <hughd@...gle.com>, 
	Baolin Wang <baolin.wang@...ux.alibaba.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-mm@...ck.org
Subject: Re: [PATCH] vfs,shmem,kernfs: fix listxattr to include security.* xattrs

On Thu, Apr 24, 2025 at 9:12 AM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
>
> On Thu, Apr 24, 2025 at 08:46:43AM -0400, Stephen Smalley wrote:
> > The vfs has long had a fallback to obtain the security.* xattrs from the
> > LSM when the filesystem does not implement its own listxattr, but
> > shmem/tmpfs and kernfs later gained their own xattr handlers to support
> > other xattrs. Unfortunately, as a side effect, tmpfs and kernfs-based
> > filesystems like sysfs no longer return the synthetic security.* xattr
> > names via listxattr unless they are explicitly set by userspace or
> > initially set upon inode creation after policy load. coreutils has
> > recently switched from unconditionally invoking getxattr for security.*
> > for ls -Z via libselinux to only doing so if listxattr returns the xattr
> > name, breaking ls -Z of such inodes.
> >
> > Before:
> > $ getfattr -m.* /run/initramfs
> > <no output>
> > $ getfattr -m.* /sys/kernel/fscaps
> > <no output>
> >
> > After:
> > $ getfattr -m.* /run/initramfs
> > security.selinux
> > $ getfattr -m.* /sys/kernel/fscaps
> > security.selinux
> >
> > Link: https://lore.kernel.org/selinux/CAFqZXNtF8wDyQajPCdGn=iOawX4y77ph0EcfcqcUUj+T87FKyA@mail.gmail.com/
> > Link: https://lore.kernel.org/selinux/20250423175728.3185-2-stephen.smalley.work@gmail.com/
> > Signed-off-by: Stephen Smalley <stephen.smalley.work@...il.com>
>
> As this "changed" in the past, shouldn't it have a "Fixes:" tag?

Yes, I'll add that on v2. Also appears that it doesn't quite correctly
handle the case where listxattr() is called with size == 0 to probe
for the required size.