linux-kernel - Re: [PATCH] fs:Fix kmemleak leak warning in getname_flags about working on unitialized memory

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Date:   Thu, 1 Sep 2016 08:10:44 -0500
From:   Eric Sandeen <sandeen@...deen.net>
To:     Al Viro <viro@...IV.linux.org.uk>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:     akpm@...ux-foundation.org, msalter@...hat.com,
        kuleshovmail@...il.com, david.vrabel@...rix.com, vbabka@...e.cz,
        ard.biesheuvel@...aro.org, jgross@...e.com,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [PATCH] fs:Fix kmemleak leak warning in getname_flags about
 working on unitialized memory

On 8/4/16 8:57 AM, Al Viro wrote:

> Don't feed the troll.  On all paths leading to that place we have
>         result->name = kname;
>         len = strncpy_from_user(kname, filename, EMBEDDED_NAME_MAX);
> or
>                 result->name = kname;
>                 len = strncpy_from_user(kname, filename, PATH_MAX);
> with failure exits taken if strncpy_from_user() returns an error, which means
> that the damn thing has already been copied into.
> 
> FWIW, it looks a lot like buggered kmemcheck; as usual, he can't be bothered
> to mention which kernel version would it be (let alone how to reproduce it
> on the kernel in question), but IIRC davej had run into some instrumentation
> breakage lately.

The original report is in https://bugzilla.kernel.org/show_bug.cgi?id=120651
if anyone is interested in it.

-Eric

> Again, don't feed the troll - you are only inviting an "improved" version
> of that garbage, just as pointless.