linux-kernel - Re: [RFC] call_with

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: <20180718201518.GX30522@ZenIV.linux.org.uk>
Date:   Wed, 18 Jul 2018 21:15:18 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Miklos Szeredi <mszeredi@...hat.com>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RFC] call_with_creds()

On Wed, Jul 18, 2018 at 09:04:11PM +0100, Al Viro wrote:
> On Wed, Jul 18, 2018 at 12:53:48PM -0700, Linus Torvalds wrote:
> > On Wed, Jul 18, 2018 at 12:46 PM Al Viro <viro@...iv.linux.org.uk> wrote:
> > >
> > > Huh?  Nevermind ->write(), what about open()?
> > 
> > What about open?
> > 
> > At open time, file->f_cred is the same as current_cred().
> 
> int cachefiles_write_page(struct fscache_storage *op, struct page *page)
> {
> ...
>         file = dentry_open(&path, O_RDWR | O_LARGEFILE, cache->cache_cred);
> 
> 
> int ecryptfs_privileged_open(struct file **lower_file,
>                              struct dentry *lower_dentry,
>                              struct vfsmount *lower_mnt,
>                              const struct cred *cred)
> ...
>         (*lower_file) = dentry_open(&req.path, flags, cred);

Actually, scratch that one - in this case it is current_cred() (whether that's
the right value or not).

cachefile_write_page() case is for real, AFAICS.