From: "Allan, Bruce W" <bruce.w.allan@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jan Beulich <JBeulich@suse.com>, Alexey Dobriyan <adobriyan@gmail.com>
Subject: RE: bug in sscanf()?
Thread-Topic: bug in sscanf()?
Thread-Index: Ac8NbKAkgHr1INwXQ8WF2Iu0CYn2gwDjdKaAAAHXLYAAELY/wA==
Date: Tue, 14 Jan 2014 00:32:13 +0000
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	<20140113233006.GP10323@ZenIV.linux.org.uk>
 <CA+55aFy_V8ze2CPmHY0Ga-K-DX_SATVu-Tb=_nKq_1Rb5WqaUQ@mail.gmail.com>
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> -----Original Message-----
> From: linus971@gmail.com [mailto:linus971@gmail.com] On Behalf Of Linus
> Torvalds
> Sent: Monday, January 13, 2014 4:23 PM
> To: Al Viro
> Cc: Allan, Bruce W; linux-kernel@vger.kernel.org; Jan Beulich; Alexey
> Dobriyan
> Subject: Re: bug in sscanf()?
> 
> On Tue, Jan 14, 2014 at 6:30 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > Comments?
> 
> Do we have actual users of this? Because I'd almost be inclined to say
> "we just don't support field widths on sscanf() and will warn" unless
> there are users.
> 
> We've done that before. The kernel has various limited functions. See
> the whole snprint() issue with %n, which we decided that supporting
> the full semantics was actually a big mistake and we actively
> *removed* code that had been misguidedly added just because people
> thought we should do everything a standard user library does..
> 
> Limiting our problem space is a *good* thing, not a bad thing.
> 
> If it's possible, of course, and we don't have nasty users.
> 
>            Linus

I was hoping to use sscanf() in this way for a driver I'm working on to support
Thunderbolt device authentication, but if it's too much to ask for I could probably
work around this.

Bruce.

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