From: Joerg Roedel <joro@8bytes.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>, iommu@lists.linux-foundation.org
Subject: Re: [PATCH] iommu/dma: Handle SG length overflow better
Date: Tue, 6 Aug 2019 17:25:29 +0200 [thread overview]
Message-ID: <20190806152529.GB1198@8bytes.org> (raw)
In-Reply-To: <fbdbb8c0e550ae559ea3eedc1fea084c0111f202.1564418681.git.robin.murphy@arm.com>
Hi Robin,
On Mon, Jul 29, 2019 at 05:46:00PM +0100, Robin Murphy wrote:
> Since scatterlist dimensions are all unsigned ints, in the relatively
> rare cases where a device's max_segment_size is set to UINT_MAX, then
> the "cur_len + s_length <= max_len" check in __finalise_sg() will always
> return true. As a result, the corner case of such a device mapping an
> excessively large scatterlist which is mergeable to or beyond a total
> length of 4GB can lead to overflow and a bogus truncated dma_length in
> the resulting segment.
>
> As we already assume that any single segment must be no longer than
> max_len to begin with, this can easily be addressed by reshuffling the
> comparison.
Has this been triggered in the wild of can this patch wait for the next
merge window?
Regards,
Joerg
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next prev parent reply other threads:[~2019-08-06 15:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 16:46 [PATCH] iommu/dma: Handle SG length overflow better Robin Murphy
2019-08-06 15:25 ` Joerg Roedel [this message]
2019-08-06 15:49 ` Robin Murphy
2019-08-07 1:11 ` Nicolin Chen
2019-08-09 15:32 ` Joerg Roedel
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