linux-kernel - [GIT PULL] userns vfs bits for v4.18-rc1

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Date:   Sun, 03 Jun 2018 23:19:59 -0500
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Linux Containers <containers@...ts.linux-foundation.org>,
        <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
        Seth Forshee <seth.forshee@...onical.com>,
        Miklos Szeredi <miklos@...redi.hu>,
        Miklos Szeredi <mszeredi@...hat.com>
Subject: [GIT PULL] userns vfs bits for v4.18-rc1

Linus,

Please pull the userns-linus branch from the git tree:

   git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git userns-linus

   HEAD: f3f1a18330ac1b717cd7a32adff38d965f365aa2 fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems

Apologies for the resend I forgot the diffstat and the subject line.

This is the last couple of vfs bits to enable root in a user namespace
to mount and manipulate a filesystem with backing store (AKA not a
virtual filesystem like proc, but a filesystem where the unprivileged
user controls the content).   The target filesystem for this work
is fuse, and Miklos should be sending you the pull request for the
fuse bits this merge window.

The two key patches are " evm: Don't update hmacs in user ns mounts" and
"vfs: Don't allow changing the link count of an inode with an invalid
uid or gid".  Those close small gaps in the vfs that would be a problem
if an unprivileged fuse filesystem is mounted.

The rest of the changes are things that are now safe to allow a root
user in a user namespace to do with a filesystem they have mounted.  The
most interesting development is that remount is now safe.

Eric W. Biederman (5):
      vfs: Don't allow changing the link count of an inode with an invalid uid or gid
      vfs: Allow userns root to call mknod on owned filesystems.
      fs: Allow superblock owner to replace invalid owners of inodes
      fs: Allow superblock owner to access do_remount_sb()
      capabilities: Allow privileged user in s_user_ns to set security.* xattrs

Seth Forshee (2):
      evm: Don't update hmacs in user ns mounts
      fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems

 fs/attr.c                           | 36 ++++++++++++++++++++++++++++--------
 fs/ioctl.c                          |  4 ++--
 fs/namei.c                          | 16 ++++++++++++----
 fs/namespace.c                      |  4 ++--
 security/commoncap.c                |  8 ++++++--
 security/integrity/evm/evm_crypto.c |  3 ++-
 6 files changed, 52 insertions(+), 19 deletions(-)

Eric