From: Herbert Xu <herb...@gondor.apana.org.au>
Date: Wed, 4 Aug 2010 21:48:51 +0800

> On Mon, Aug 02, 2010 at 02:45:37PM +0200, Szilveszter Ördög wrote:
>> If a scatterwalk chain contains an entry with an unaligned offset then
>> hash_walk_next() will cut off the next step at the next alignment point.
>> 
>> However, if the entry ends before the next alignment point then we will want 
>> to
>> process more data than it is available.
>> 
>> Fix this by checking whether the next aligment point is before the end of the
>> current entry.
>> ---
>>  crypto/ahash.c |    7 +++++--
>>  1 files changed, 5 insertions(+), 2 deletions(-)
>> 
>> diff --git a/crypto/ahash.c b/crypto/ahash.c
>> index b8c59b8..f669822 100644
>> --- a/crypto/ahash.c
>> +++ b/crypto/ahash.c
>> @@ -47,8 +47,11 @@ static int hash_walk_next(struct crypto_hash_walk *walk)
>>      walk->data = crypto_kmap(walk->pg, 0);
>>      walk->data += offset;
>> 
>> -    if (offset & alignmask)
>> -            nbytes = alignmask + 1 - (offset & alignmask);
>> +    if (offset & alignmask) {
>> +            unsigned int unaligned = alignmask + 1 - (offset & alignmask);
>> +            if (nbytes > unaligned)
>> +                    nbytes = unaligned;
>> +    }
>> 
>>      walk->entrylen -= nbytes;
>>      return nbytes;
> 
> The patch looks OK to me.  Dave, what do you think?

Looks good, thanks Szilveszter:

Acked-by: David S. Miller <da...@davemloft.net>
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