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From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: "J. Bruce Fields" <bfields@redhat.com>
Cc: linux-nfs@vger.kernel.org
Subject: Re: [PATCH 08/16] nfsd: escape high characters in binary data
Date: Wed, 7 Aug 2019 12:00:07 +0300
Message-ID: <20190807090007.GK30120@smile.fi.intel.com> (raw)
In-Reply-To: <20190806185008.GC9456@parsley.fieldses.org>

On Tue, Aug 06, 2019 at 02:50:08PM -0400, J. Bruce Fields wrote:
> On Tue, Aug 06, 2019 at 03:19:31PM +0300, Andy Shevchenko wrote:
> > On Thu, Jun 20, 2019 at 10:51:07AM -0400, J. Bruce Fields wrote:
> > > From: "J. Bruce Fields" <bfields@redhat.com>
> > > 
> > > I'm exposing some information about NFS clients in pseudofiles.  I
> > > expect to eventually have simple tools to help read those pseudofiles.
> > > 
> > > But it's also helpful if the raw files are human-readable to the extent
> > > possible.  It aids debugging and makes them usable on systems that don't
> > > have the latest nfs-utils.
> > > 
> > > A minor challenge there is opaque client-generated protocol objects like
> > > state owners and client identifiers.  Some clients generate those to
> > > include handy information in plain ascii.  But they may also include
> > > arbitrary byte sequences.
> > > 
> > > I think the simplest approach is to limit to isprint(c) && isascii(c)
> > > and escape everything else.
> > > 
> > > That means you can just cat the file and get something that looks OK.
> > > Also, I'm trying to keep these files legal YAML, which requires them to
> > > UTF-8, and this is a simple way to guarantee that.
> > 
> > Two questions:
> > - why can't be original function extended to cover this case
> >   (using additional flags, maybe)?
> 
> I found the ESCAPE_NP/"only" logic made it a little difficult to extend
> string_escape_mem().

Maybe it requires more thinking about?
I think it is still possible to extend existing, rather to take workarounds
like this one.

> So, I wrote a patch series that removes the string_escape_mem flags that
> aren't used

Have you considered the potential users that can be converted to use
string_escape_mem()?

I know about at least one (needs to be reworked a bit, but it is in slow
progress).

There are potentially others that would be converted using "unused" flags.

>, simplifies it a bit, then separates the flags into two
> different types: those that select which characters to escape
> (non-printable, non-ascii, whitespace, etc.) and those that choose a
> style of escaping to use (octal, hex, or \\).  That seems to make the
> code a little easier to extend while still covering the cases people
> actually use.  I'll try to get those out this week and you can tell me
> what you think.

Will be glad to help!

In any case regarding to this one, I would like rather to see it's never
appeared, or now will be gone in favour of string_escape_mem() extension.

-- 
With Best Regards,
Andy Shevchenko



  reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20 14:50 [PATCH 00/16] exposing knfsd client state to userspace J. Bruce Fields
2019-06-20 14:51 ` [PATCH 01/16] nfsd: persist nfsd filesystem across mounts J. Bruce Fields
2019-06-20 14:51 ` [PATCH 02/16] nfsd: rename cl_refcount J. Bruce Fields
2019-06-20 14:51 ` [PATCH 03/16] nfsd4: use reference count to free client J. Bruce Fields
2019-06-20 14:51 ` [PATCH 04/16] nfsd: add nfsd/clients directory J. Bruce Fields
2019-06-20 14:51 ` [PATCH 05/16] nfsd: make client/ directory names small ints J. Bruce Fields
2019-06-20 14:51 ` [PATCH 06/16] nfsd4: add a client info file J. Bruce Fields
2019-06-20 14:51 ` [PATCH 07/16] nfsd: copy client's address including port number to cl_addr J. Bruce Fields
2019-06-20 14:51 ` [PATCH 08/16] nfsd: escape high characters in binary data J. Bruce Fields
2019-06-21 17:45   ` bfields
2019-06-21 22:26     ` Kees Cook
2019-06-22 19:00       ` J. Bruce Fields
2019-06-22 20:22         ` Kees Cook
2019-06-24 21:05           ` J. Bruce Fields
2019-06-26 16:21             ` J. Bruce Fields
2019-06-27  4:16               ` Kees Cook
2019-06-27 15:23                 ` J. Bruce Fields
2019-06-27 20:21               ` J. Bruce Fields
2019-06-28  3:58                 ` Kees Cook
2019-06-28 16:33                   ` J. Bruce Fields
2019-07-10 22:09                     ` J. Bruce Fields
2019-07-11  1:54                       ` Kees Cook
2019-08-06 12:19   ` Andy Shevchenko
2019-08-06 18:50     ` J. Bruce Fields
2019-08-07  9:00       ` Andy Shevchenko [this message]
2019-08-08 11:28         ` bfields
2019-08-27 13:36           ` Andy Shevchenko
2019-06-20 14:51 ` [PATCH 09/16] nfsd: add more information to client info file J. Bruce Fields
2019-06-20 14:51 ` [PATCH 10/16] nfsd4: add file to display list of client's opens J. Bruce Fields
2019-06-20 14:51 ` [PATCH 11/16] nfsd: show lock and deleg stateids J. Bruce Fields
2019-06-20 14:51 ` [PATCH 12/16] nfsd4: show layout stateids J. Bruce Fields
2019-06-20 14:51 ` [PATCH 13/16] nfsd: create get_nfsdfs_clp helper J. Bruce Fields
2019-06-20 14:51 ` [PATCH 14/16] nfsd: allow forced expiration of NFSv4 clients J. Bruce Fields
2019-06-20 14:51 ` [PATCH 15/16] nfsd: create xdr_netobj_dup helper J. Bruce Fields
2019-06-20 14:51 ` [PATCH 16/16] nfsd: decode implementation id J. Bruce Fields
2019-06-21 18:13 ` [PATCH 00/16] exposing knfsd client state to userspace bfields
2019-06-21 19:25   ` Anna Schumaker
2019-06-21 22:08     ` J. Bruce Fields

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