From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Prem Karat <pkarat@mvista.com>, linux-mips@linux-mips.org
Cc: ddaney.cavm@gmail.com
Subject: Re: [RFC PATCH 1/1] MIPS: Enable VDSO randomization.
Date: Sat, 19 Apr 2014 17:49:53 +0400 [thread overview]
Message-ID: <53527F01.30003@cogentembedded.com> (raw)
In-Reply-To: <20140419093302.GH2717@064904.mvista.com>
Hello.
On 19-04-2014 13:33, Prem Karat wrote:
> Based on commit 1091458d09e1a (mmap randomization)
> For 32-bit address spaces randomize within a
> 16MB space, for 64-bit within a 256MB space.
> Signed-off-by: Prem Karat <pkarat@mvista.com>
[...]
> @@ -67,7 +69,18 @@ subsys_initcall(init_vdso);
>
> static unsigned long vdso_addr(unsigned long start)
> {
> - return STACK_TOP;
> + unsigned long offset = 0UL;
> +
> + if (current->flags & PF_RANDOMIZE) {
> + offset = get_random_int();
> + offset = offset << PAGE_SHIFT;
Why not:
offset <<= PAGE_SHIFT;
> + if (TASK_IS_32BIT_ADDR)
> + offset &= 0xfffffful;
> + else
> + offset &= 0xffffffful;
> + }
> +
> + return (STACK_TOP + offset);
Parens not needed.
WBR, Sergei
next prev parent reply other threads:[~2014-04-19 13:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-19 9:33 [RFC PATCH 1/1] MIPS: Enable VDSO randomization Prem Karat
2014-04-19 13:49 ` Sergei Shtylyov [this message]
2014-04-19 22:56 ` David Daney
2014-04-21 3:40 ` Prem Karat
2014-04-21 18:38 ` David Daney
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