Re: Provider: cannot sign with ed25519-like key

Hey Matt,

yeah point on. Its too hot I guess, was just checking the last memory 
address numbers.

So you mean that somewhere the context contains a "wrong" key?

Bernd

Am 12.08.24 um 15:22 schrieb Matt Caswell:
> 
> 
> On 12/08/2024 14:17, 'Bernd Ritter' via openssl-users wrote:
>> Hey there,
>>
>> debugging actually solved it, there was a silent other error that 
>> caused problems, but not visual problem I saw. Got that fixed, many 
>> thanks for that!
>>
>> Following through with debugging I got to the next road block. My 
>> provider is now trying to sign some payload. It calls 
>> OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE for the first time. I guess 
>> this should be OSSL_FUNC_SIGNATURE_DIGEST_SIGN, but I have no idea to 
>> enforce this.
>>
>> It's the same context, same data, same data size.
> 
> You say its the same context, and yet the ctx pointer seems to be 
> different in the debugging output you showed, i.e. ctx=0x5555556a2e40 
> compared to ctx=0x5555556bac40.
> 
> So are you sure it is the same ctx?
> 
> Matt
> 
>>
>> Breakpoint 1, EVP_DigestSignUpdate (ctx=0x5555556a2e40, 
>> data=0x7fffffffc3b0, dsize=29) at crypto/evp/m_sigver.c:419
>> 423         if (pctx->op.sig.signature->digest_sign_update == NULL) {
>> 428         return pctx->op.sig.signature->digest_sign_update(pctx- 
>>  >op.sig.algctx,
>> (gdb) n
>> ed25519ph-provider/src/ed25519ph_sign_x509.c - digest sign update. 
>> datalen=29
>>
>> Now when the provider wants to close the deal, the digest_sign_update 
>> from the context is now NULL suddenly.
>>
>> Breakpoint 1, EVP_DigestSignUpdate (ctx=0x5555556bac40, 
>> data=0x7fffffffc3b0, dsize=29) at crypto/evp/m_sigver.c:419
>> 423         if (pctx->op.sig.signature->digest_sign_update == NULL) {
>> 424             ERR_raise(ERR_LIB_EVP, 
>> ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
>>
>> ed25519ph-provider/src/ed25519ph_sign_x509.c - digest sign update 
>> failed rc=0. error:030C0101:digital envelope routines::called a 
>> function you should not call
>> Error signing raw input data
>> Public Key operation error
>>
>> I've also tried the "trick" from Steffen who mentioned earlier a hacky 
>> way to enforce block operation.
>>
>> All the best,
>> Bernd
>>
>> Am 12.08.24 um 12:33 schrieb Matt Caswell:
>>>
>>>
>>> On 12/08/2024 11:08, 'Bernd Ritter' via openssl-users wrote:
>>>> I do not understand how the parameter list can change? As my 
>>>> debugging logs are called, it seems that my get_params is called 
>>>> accordingly.
>>>>
>>>
>>> I don't really understand what you mean by this. Each invocation of 
>>> your get_params function may request different parameters depending 
>>> on which parameters the caller is interested in for any given context.
>>>
>>> As I previously mentioned the "unknown max size" error comes from the 
>>> EVP_PKEY_get_size() function, and this ultimately gets the size by 
>>> querying the OSSL_PKEY_PARAM_MAX_SIZE parameter.
>>>
>>> The value of this parameter is cached in the pkey. This happens here 
>>> in OpenSSL:
>>>
>>> https://github.com/openssl/openssl/ 
>>> blob/2f33265039cdbd0e4589c80970e02e208f3f94d2/crypto/evp/ 
>>> keymgmt_lib.c#L289-L313
>>>
>>> This is the point in libcrypto where your provider is called and the 
>>> OSSL_PKEY_PARAM_MAX_SIZE parameter is queried - the result of which 
>>> is cached in the cache.size field of the pkey. All subsequent calls 
>>> to `EVP_PEKY_get_size()` will refer to this cache and give the 
>>> "unknown max_size" error if this cached size is <= 0.
>>>
>>> If you are struggling to see how this fits together with what your 
>>> code is doing then I suggest you build OpenSSL with debug symbols on 
>>> and set a breakpoint in the `evp_keymgmt_util_cache_keyinfo` function 
>>> I linked to above and step through what is happening in the 
>>> interaction with your provider.
>>>
>>> Matt
>>>
>>
> 

-- 
Bernd Ritter
Senior Linux Developer
Tel.: +49 175 534 4534
Mail: ritter-shG/GajIFYqbacvFa/[email protected]

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