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From: Amir Goldstein <amir73il@gmail.com>
To: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
	Seth Forshee <sforshee@digitalocean.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: Re: [PATCH 03/10] fs: tweak fsuidgid_has_mapping()
Date: Tue, 30 Nov 2021 08:44:58 +0200	[thread overview]
Message-ID: <CAOQ4uxgdwn8QSAHoubd7ZOWWn7hBoTu2naXdjv0fffEVQaMNGA@mail.gmail.com> (raw)
In-Reply-To: <20211123114227.3124056-4-brauner@kernel.org>

On Tue, Nov 23, 2021 at 3:29 PM Christian Brauner <brauner@kernel.org> wrote:
>
> From: Christian Brauner <christian.brauner@ubuntu.com>
>
> If the caller's fs{g,u}id aren't mapped in the mount's idmapping we can
> return early and skip the check whether the mapped fs{g,u}id also have a
> mapping in the filesystem's idmapping. If the fs{g,u}id aren't mapped in
> the mount's idmapping they consequently can't be mapped in the
> filesystem's idmapping. So there's no point in checking that.
>
> Cc: Seth Forshee <sforshee@digitalocean.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> CC: linux-fsdevel@vger.kernel.org
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> ---
Reviewed-by: Amir Goldstein <amir73il@gmail.com>

>  include/linux/fs.h | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index eb69e8b035fa..161b5936094e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1695,10 +1695,18 @@ static inline void inode_fsgid_set(struct inode *inode,
>  static inline bool fsuidgid_has_mapping(struct super_block *sb,
>                                         struct user_namespace *mnt_userns)
>  {
> -       struct user_namespace *s_user_ns = sb->s_user_ns;
> +       struct user_namespace *fs_userns = sb->s_user_ns;
> +       kuid_t kuid;
> +       kgid_t kgid;
>
> -       return kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) &&
> -              kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns));
> +       kuid = mapped_fsuid(mnt_userns);
> +       if (!uid_valid(kuid))
> +               return false;
> +       kgid = mapped_fsgid(mnt_userns);
> +       if (!gid_valid(kgid))
> +               return false;
> +       return kuid_has_mapping(fs_userns, kuid) &&
> +              kgid_has_mapping(fs_userns, kgid);
>  }
>
>  extern struct timespec64 current_time(struct inode *inode);
> --
> 2.30.2
>

  reply	other threads:[~2021-11-30  6:45 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23 11:42 [PATCH 00/10] Extend and tweak mapping support Christian Brauner
2021-11-23 11:42 ` [PATCH 01/10] fs: add is_mapped_mnt() helper Christian Brauner
2021-11-30  6:25   ` Amir Goldstein
2021-11-30  8:48     ` Christian Brauner
2021-11-23 11:42 ` [PATCH 02/10] fs: move mapping helpers Christian Brauner
2021-11-30  6:35   ` Amir Goldstein
2021-11-30  8:53     ` Christian Brauner
2021-11-23 11:42 ` [PATCH 03/10] fs: tweak fsuidgid_has_mapping() Christian Brauner
2021-11-30  6:44   ` Amir Goldstein [this message]
2021-11-23 11:42 ` [PATCH 04/10] fs: account for filesystem mappings Christian Brauner
2021-11-23 11:42 ` [PATCH 05/10] docs: update mapping documentation Christian Brauner
2021-11-23 11:42 ` [PATCH 06/10] fs: use low-level mapping helpers Christian Brauner
2021-11-23 11:42 ` [PATCH 07/10] fs: remove unused " Christian Brauner
2021-11-30  6:53   ` Amir Goldstein
2021-11-23 11:42 ` [PATCH 08/10] fs: port higher-level " Christian Brauner
2021-11-30  7:15   ` Amir Goldstein
2021-11-30  8:52     ` Christian Brauner
2021-11-23 11:42 ` [PATCH 09/10] fs: add i_user_ns() helper Christian Brauner
2021-11-30  7:02   ` Amir Goldstein
2021-11-23 11:42 ` [PATCH 10/10] fs: support mapped mounts of mapped filesystems Christian Brauner
2021-11-29 10:36 ` [PATCH 00/10] Extend and tweak mapping support Christian Brauner
2021-11-30  5:51 ` Amir Goldstein

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