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From: Mike Rapoport <rppt@kernel.org>
To: Topi Miettinen <toiwoton@gmail.com>
Cc: linux-hardening@vger.kernel.org, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andy Lutomirski <luto@kernel.org>, Jann Horn <jannh@google.com>,
	Kees Cook <keescook@chromium.org>,
	Linux API <linux-api@vger.kernel.org>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] mm/vmalloc: randomize vmalloc() allocations
Date: Thu, 3 Dec 2020 08:58:01 +0200	[thread overview]
Message-ID: <20201203065801.GH751215@kernel.org> (raw)
In-Reply-To: <9d34fb0a-7aba-1e84-6426-006ea7c3d9f5@gmail.com>

On Wed, Dec 02, 2020 at 08:49:06PM +0200, Topi Miettinen wrote:
> On 1.12.2020 23.45, Topi Miettinen wrote:
> > Memory mappings inside kernel allocated with vmalloc() are in
> > predictable order and packed tightly toward the low addresses. With
> > new kernel boot parameter 'randomize_vmalloc=1', the entire area is
> > used randomly to make the allocations less predictable and harder to
> > guess for attackers.
> > 
> 
> This also seems to randomize module addresses. I was going to check that
> next, so nice surprise!

Heh, that's because module_alloc() uses vmalloc() in that way or another :)

> -Topi
> 
> >   	spin_unlock(&free_vmap_area_lock);
> >   	if (unlikely(addr == vend))
> > 
> 

-- 
Sincerely yours,
Mike.

  reply	other threads:[~2020-12-03  6:59 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-01 21:45 Topi Miettinen
2020-12-02 18:49 ` Topi Miettinen
2020-12-03  6:58   ` Mike Rapoport [this message]
2020-12-03 23:15     ` David Laight
2020-12-04 10:58       ` Topi Miettinen
2020-12-04 13:33         ` David Laight
2020-12-04 16:53           ` Topi Miettinen
2020-12-09 19:08     ` Topi Miettinen
2020-12-10 19:58     ` Topi Miettinen
2020-12-02 18:53 ` Matthew Wilcox
2020-12-02 21:28   ` Topi Miettinen

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