From: tianyu zhou <tyjoe.linux@gmail.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org
Subject: Missing check for CAP_SYS_ADMIN before calling reconfigure_super()
Date: Mon, 31 May 2021 23:17:34 +0800 [thread overview]
Message-ID: <CAM6ytZqioJ91r8Ax7KpNzkF0Ai9DSoU0oVt0VOT2Svv=zSGvRA@mail.gmail.com> (raw)
Hi, there exists a check for CAP_SYS_ADMIN in do_remount(),
do_umount() and vfs_fsconfig_locked() before they finally call
reconfigure_super().
---------------------
// fs/namespace.c
static int do_umount(struct mount *mnt, int flags)
{
...
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
return do_umount_root(sb);
...
}
static int do_umount_root(struct super_block *sb)
{
...
ret = reconfigure_super(fc);
...
}
---------------------
However, for function do_emergency_remount_callback(), vfs_get_super()
and reconfigure_single() in fs/super.c, there is no such check for
CAP_SYS_ADMIN before calling reconfigure_super(), neither do their
callers.
Is this a missing check bug which may break the protection for superblock?
Thanks!
Best regards,
Tianyu
reply other threads:[~2021-05-31 17:09 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAM6ytZqioJ91r8Ax7KpNzkF0Ai9DSoU0oVt0VOT2Svv=zSGvRA@mail.gmail.com' \
--to=tyjoe.linux@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.