linux-kernel - Re: [RESEND PATCH] x86: add phys addr validity check for /dev/mem mmap

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Message-ID: <524C5BFB.5050501@zytor.com>
Date:	Wed, 02 Oct 2013 10:46:35 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Frantisek Hrbata <fhrbata@...hat.com>
CC:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
	oleg@...hat.com, kamaleshb@...ibm.com, hechjie@...ibm.com,
	akpm@...ux-foundation.org, dave.hansen@...el.com
Subject: Re: [RESEND PATCH] x86: add phys addr validity check for /dev/mem
 mmap

On 10/02/2013 09:05 AM, Frantisek Hrbata wrote:
> +
> +int valid_phys_addr_range(phys_addr_t addr, size_t count)
> +{
> +	return addr + count <= __pa(high_memory);
> +}
> +
> +int valid_mmap_phys_addr_range(unsigned long pfn, size_t count)
> +{
> +	resource_size_t addr = (pfn << PAGE_SHIFT) + count;
> +	return phys_addr_valid(addr);
> +}
> 

The latter has overflow problems.

The former I realize matches the current /dev/mem, but it is still just
plain wrong in multiple ways.

	-hpa

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