2021-01-02 21:27:14

by Herbert Xu

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Subject: Re: [PATCH 1/6] drivers: crypto: qce: sha: Restore/save sha1_state/sha256_state with qce_sha_reqctx in export/import

On Fri, Dec 18, 2020 at 10:30:22PM -0500, Thara Gopinath wrote:
> Export and import interfaces save and restore partial transformation
> states. The partial states were being stored and restored in struct
> sha1_state for sha1/hmac(sha1) transformations and sha256_state for
> sha256/hmac(sha256) transformations.This led to a bunch of corner cases
> where improper state was being stored and restored. A few of the corner
> cases that turned up during testing are:
>
> - wrong byte_count restored if export/import is called twice without h/w
> transaction in between
> - wrong buflen restored back if the pending buffer
> length is exactly the block size.
> - wrong state restored if buffer length is 0.
>
> To fix these issues, save and restore the entire qce_sha_rctx structure
> instead of parts of it in sha1_state and sha256_state structures.
> This in turn simplifies the export and import apis.
>
> Signed-off-by: Thara Gopinath <[email protected]>
> ---
> drivers/crypto/qce/sha.c | 93 ++++------------------------------------
> 1 file changed, 8 insertions(+), 85 deletions(-)

How is this safe when the reqctx structure contains pointers?

Cheers,
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


2021-01-08 15:52:09

by Thara Gopinath

[permalink] [raw]
Subject: Re: [PATCH 1/6] drivers: crypto: qce: sha: Restore/save sha1_state/sha256_state with qce_sha_reqctx in export/import



On 1/2/21 4:25 PM, Herbert Xu wrote:
> On Fri, Dec 18, 2020 at 10:30:22PM -0500, Thara Gopinath wrote:
>> Export and import interfaces save and restore partial transformation
>> states. The partial states were being stored and restored in struct
>> sha1_state for sha1/hmac(sha1) transformations and sha256_state for
>> sha256/hmac(sha256) transformations.This led to a bunch of corner cases
>> where improper state was being stored and restored. A few of the corner
>> cases that turned up during testing are:
>>
>> - wrong byte_count restored if export/import is called twice without h/w
>> transaction in between
>> - wrong buflen restored back if the pending buffer
>> length is exactly the block size.
>> - wrong state restored if buffer length is 0.
>>
>> To fix these issues, save and restore the entire qce_sha_rctx structure
>> instead of parts of it in sha1_state and sha256_state structures.
>> This in turn simplifies the export and import apis.
>>
>> Signed-off-by: Thara Gopinath <[email protected]>
>> ---
>> drivers/crypto/qce/sha.c | 93 ++++------------------------------------
>> 1 file changed, 8 insertions(+), 85 deletions(-)
>
> How is this safe when the reqctx structure contains pointers?

Hi Herbert,

You are right. Also more I think about this, it is better to have
another struct to export and import the relevant pieces.
I will fix this and send across a v2.

>
> Cheers,
>

--
Warm Regards
Thara