linux-kernel - Re: [PATCH] Fix for binary

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Date:	Thu, 15 Dec 2011 14:38:58 -0800
From:	Michel Lespinasse <walken@...gle.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Al Viro <viro@...iv.linux.org.uk>,
	Christoph Hellwig <hch@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix for binary_sysctl() memory leak

On Thu, Dec 15, 2011 at 2:19 PM, Andrew Morton
<akpm@...ux-foundation.org> wrote:
> I think the patch is correct but the description is misleading?
>
> I see no memory leak here.  Calling __putname() directly simply
> bypasses some audit-related stuff.

Hmmm, maybe I wasn't explicit enough about it. We are definitely
seeing a memory leak without the patch.

When auditing is enabled, putname() calls audit_putname *instead* (not
in addition) to __putname(). Then, if a syscall is in progress,
audit_putname does not release the name - instead, it expects the name
to get released when the syscall completes, but that will happen only
if audit_getname() was called previously, i.e. if the name was
allocated with getname() rather than the naked __getname(). So,
__getname() followed by putname() ends up leaking memory.

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
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