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Message-ID: <9a8748490706241608r6814463fl997e36c8916f7561@mail.gmail.com>
Date: Mon, 25 Jun 2007 01:08:27 +0200
From: "Jesper Juhl" <jesper.juhl@...il.com>
To: "Andrew Morton" <akpm@...ux-foundation.org>
Cc: "Richard Henderson" <rth@...u.edu>,
"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Avoid potential NULL deref in scripts/genksyms/lex.l
On 25/06/07, Andrew Morton <akpm@...ux-foundation.org> wrote:
> On Mon, 25 Jun 2007 00:02:03 +0200 "Jesper Juhl" <jesper.juhl@...il.com> wrote:
>
> > > > + if (!file || !e)
> > > > + exit(1);
> > > > *e = '\0';
> > > > cur_filename = memcpy(xmalloc(e-file+1), file, e-file+1);
> > > > cur_line = atoi(yytext+2);
> > >
> > > I don't think the bug which you're fixing can occur:
> > >
> > > ^#[ \t]+{INT}[ \t]+\"[^\"\n]+\".*\n return FILENAME;
> > >
> > > has anyone reported crashes in there?
> > >
> >
> > It may indeed not be possible. Found by inspection, not by any actual
> > observed crashes.
> > But does it really hurt to be defensive here? In case it can somehow
> > be caused to fail, with my patch it'll fail a bit nicer :) It's not
> > like it's at all speed critical code that will be hurt by that extra
> > 'if'...
>
> We can only get NULL pointers here if the regexp is wrong or if there's
> a bug in the regexp parser. Getting a coredump at the failure site is
> much better behaviour than mysteriously exiting.
>
Fair enough. Just ignore the patch then :-)
--
Jesper Juhl <jesper.juhl@...il.com>
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