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Subject: Re: [PATCH 3/6] crypto: omap-crypto: fix userspace copied buffer
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To:     Herbert Xu <herbert@gondor.apana.org.au>
CC:     <davem@davemloft.net>, <linux-crypto@vger.kernel.org>,
        <linux-omap@vger.kernel.org>
References: <20200429144205.5291-1-t-kristo@ti.com>
 <20200429144205.5291-4-t-kristo@ti.com>
 <20200508050848.GA21823@gondor.apana.org.au>
From:   Tero Kristo <t-kristo@ti.com>
Message-ID: <4c7e94c4-3e09-5344-1ec7-b998a4d7fd65@ti.com>
Date:   Fri, 8 May 2020 08:47:11 +0300
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On 08/05/2020 08:08, Herbert Xu wrote:
> On Wed, Apr 29, 2020 at 05:42:02PM +0300, Tero Kristo wrote:
>>
>> diff --git a/drivers/crypto/omap-crypto.c b/drivers/crypto/omap-crypto.c
>> index cc88b7362bc2..cbc5a4151c3c 100644
>> --- a/drivers/crypto/omap-crypto.c
>> +++ b/drivers/crypto/omap-crypto.c
>> @@ -178,11 +178,14 @@ static void omap_crypto_copy_data(struct scatterlist *src,
>>   		amt = min(src->length - srco, dst->length - dsto);
>>   		amt = min(len, amt);
>>   
>> -		srcb = sg_virt(src) + srco;
>> -		dstb = sg_virt(dst) + dsto;
>> +		srcb = kmap_atomic(sg_page(src)) + srco + src->offset;
>> +		dstb = kmap_atomic(sg_page(dst)) + dsto + dst->offset;
>>   
>>   		memcpy(dstb, srcb, amt);
>>   
>> +		kunmap_atomic(srcb);
>> +		kunmap_atomic(dstb);
> 
> With dst you also need to flush the cache.  Please refer to the
> flush dcache call in include/crypto/scatterwalk.h.

Ok, let me try that out, flushing a single page should be fine (meaning 
not catastrophic to performance.)

-Tero
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