Re: [PATCH] crypto: authenc - cryptlen must be at least AAD len

["Stephan Müller" <smueller@chronox.de>]

Am Donnerstag, 7. September 2017, 05:54:05 CEST schrieb Herbert Xu:

Hi Herbert,
> > 
> > What is your opinion: should this check be rather added to
> > crypto_aead_encrypt (similar to a sanity check found in
> > crypto_aead_decrypt)?
> 
> Doesn't this apply to decryption as well?

There is already such check:

static inline int crypto_aead_decrypt(struct aead_request *req)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);

        if (req->cryptlen < crypto_aead_authsize(aead))
                return -EINVAL;
...

> Perhaps we can simply
> truncate assoclen in aead_request_set_ad.

I am not sure that would work because at the time we set the AAD len, we may 
not yet have cryptlen. I.e. aead_request_set_ad may be called before 
aead_request_set_crypt.


Ciao
Stephan