From: "J. Bruce Fields" <bfields@fieldses.org>
To: Kees Cook <keescook@chromium.org>
Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/16] nfsd: escape high characters in binary data
Date: Thu, 27 Jun 2019 16:21:24 -0400 [thread overview]
Message-ID: <20190627202124.GC16388@fieldses.org> (raw)
In-Reply-To: <20190626162149.GB4144@fieldses.org>
On Wed, Jun 26, 2019 at 12:21:49PM -0400, J. Bruce Fields wrote:
> On Mon, Jun 24, 2019 at 05:05:12PM -0400, J. Bruce Fields wrote:
> > On Sat, Jun 22, 2019 at 01:22:56PM -0700, Kees Cook wrote:
> > > On Sat, Jun 22, 2019 at 03:00:58PM -0400, J. Bruce Fields wrote:
> > > > The logic around ESCAPE_NP and the "only" string is really confusing. I
> > > > started assuming I could just add an ESCAPE_NONASCII flag and stick "
> > > > and \ into the "only" string, but it doesn't work that way.
> > >
> > > Yeah, if ESCAPE_NP isn't specified, the "only" characters are passed
> > > through. It'd be nice to have an "add" or a clearer way to do actual
> > > ctype subsets, etc. If there isn't an obviously clear way to refactor
> > > it, just skip it for now and I'm happy to ack your original patch. :)
> >
> > There may well be some simplification possible here.... There aren't
> > really many users of "only", for example. I'll look into it some more.
>
> The printk users are kind of mysterious to me. I did a grep for
>
> git grep '%[0-9.*]pE'
>
> which got 75 hits. All of them for pE. I couldn't find any of the
> other pE[achnops] variants. pE is equivalent to ESCAPE_ANY|ESCAPE_NP.
> Confusingly, ESCAPE_NP doesn't mean "escape non-printable", it means
> "don't escape printable". So things like carriage returns aren't
> escaped.
No, I was confused: "\n" is non-printable according to isprint(), so
ESCAPE_ANY_NP *will* escape it. So this isn't quite so bad. SSIDs are
usually printed as '%*pE', so arguably we should be escaping the single
quote character too, but at least we're not allowing line breaks
through. I don't know about non-ascii.
> One of the hits outside wireless code was in drm_dp_cec_adap_status,
> which was printing some device ID into a debugfs file with "ID: %*pE\n".
> If the ID actually needs escaping, then I suspect the meant to escape \n
> too to prevent misparsing that output.
And same here, this is OK.
--b.
next prev parent reply other threads:[~2019-06-27 20:21 UTC|newest]
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 ` J. Bruce Fields
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 [this message]
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
2019-08-08 11:28 ` J. Bruce Fields
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 J. Bruce Fields
2019-06-21 19:25 ` Anna Schumaker
2019-06-21 22:08 ` J. Bruce Fields
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