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From: Laura Abbott <labbott@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Anderson <anderson@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Ingo Molnar <mingo@kernel.org>, Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH] proc/kcore: Don't bounds check against address 0
Date: Tue, 1 May 2018 15:26:00 -0700	[thread overview]
Message-ID: <4db64722-47b5-767c-4090-bdd9c1522e96@redhat.com> (raw)
In-Reply-To: <20180501144604.1cf872e7938bffc01a26349f@linux-foundation.org>

On 05/01/2018 02:46 PM, Andrew Morton wrote:
> On Tue,  1 May 2018 13:11:43 -0700 Laura Abbott <labbott@redhat.com> wrote:
> 
>> The existing kcore code checks for bad addresses against
>> __va(0) with the assumption that this is the lowest address
>> on the system. This may not hold true on some systems (e.g.
>> arm64) and produce overflows and crashes. Switch to using
>> other functions to validate the address range.
>>
>> Tested-by: Dave Anderson <anderson@redhat.com>
>> Signed-off-by: Laura Abbott <labbott@redhat.com>
>> ---
>> I took your previous comments as a tested by, please let me know if that
>> was wrong. This should probably just go through -mm. I don't think this
>> is necessary for stable but I can request it later if necessary.
> 
> I'm surprised.  "overflows and crashes" sounds rather serious??
> 

It's currently only seen on arm64 and it's not clear if anyone
wants to use that particular combination on a stable release.
I think a better phrase is "this is not urgent for stable".

Thanks,
Laura

WARNING: multiple messages have this Message-ID (diff)
From: labbott@redhat.com (Laura Abbott)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] proc/kcore: Don't bounds check against address 0
Date: Tue, 1 May 2018 15:26:00 -0700	[thread overview]
Message-ID: <4db64722-47b5-767c-4090-bdd9c1522e96@redhat.com> (raw)
In-Reply-To: <20180501144604.1cf872e7938bffc01a26349f@linux-foundation.org>

On 05/01/2018 02:46 PM, Andrew Morton wrote:
> On Tue,  1 May 2018 13:11:43 -0700 Laura Abbott <labbott@redhat.com> wrote:
> 
>> The existing kcore code checks for bad addresses against
>> __va(0) with the assumption that this is the lowest address
>> on the system. This may not hold true on some systems (e.g.
>> arm64) and produce overflows and crashes. Switch to using
>> other functions to validate the address range.
>>
>> Tested-by: Dave Anderson <anderson@redhat.com>
>> Signed-off-by: Laura Abbott <labbott@redhat.com>
>> ---
>> I took your previous comments as a tested by, please let me know if that
>> was wrong. This should probably just go through -mm. I don't think this
>> is necessary for stable but I can request it later if necessary.
> 
> I'm surprised.  "overflows and crashes" sounds rather serious??
> 

It's currently only seen on arm64 and it's not clear if anyone
wants to use that particular combination on a stable release.
I think a better phrase is "this is not urgent for stable".

Thanks,
Laura

  reply	other threads:[~2018-05-01 22:26 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <981100282.24860394.1524770798522.JavaMail.zimbra@redhat.com>
2018-04-26 19:31 ` BUG: /proc/kcore does not export direct-mapped memory on arm64 (and presumably some other architectures) Dave Anderson
2018-04-26 21:16   ` Kees Cook
2018-04-28  0:58     ` Laura Abbott
2018-04-30 14:03       ` Dave Anderson
2018-05-01 14:45         ` Dave Anderson
2018-05-01 20:11           ` [PATCH] proc/kcore: Don't bounds check against address 0 Laura Abbott
2018-05-01 20:11             ` Laura Abbott
2018-05-01 21:46             ` Andrew Morton
2018-05-01 21:46               ` Andrew Morton
2018-05-01 22:26               ` Laura Abbott [this message]
2018-05-01 22:26                 ` Laura Abbott

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