[PATCH v2 2/5] lib: implement sm3 256 hash

[Heiko Schocher]

Hello Ilias,

On 11.11.25 10:47, Ilias Apalodimas wrote:
> I think this would be easier to review/ack if you split the cmd
> implementation from the actual hashing algo.

Okay, I will split it in v3 into 2 patches.

> 
> [...]
> 
>> +void sm3_init(struct sm3_context *sctx)
>> +{
>> +       memset(sctx, 0, sizeof(struct sm3_context));
> 
> I usually prefer sizeof(*sctx), but up to you

Hmm.. I have no preference here ... so I change it.

>> +
>> +       /* Load initial values */
>> +       sctx->state[0] = SM3_IVA;
>> +       sctx->state[1] = SM3_IVB;
>> +       sctx->state[2] = SM3_IVC;
>> +       sctx->state[3] = SM3_IVD;
>> +       sctx->state[4] = SM3_IVE;
>> +       sctx->state[5] = SM3_IVF;
>> +       sctx->state[6] = SM3_IVG;
>> +       sctx->state[7] = SM3_IVH;
>> +       sctx->count = 0;
>> +}
>> +
>> +static inline void sm3_block(struct sm3_context *sctx,
>> +               u8 const *data, int blocks, u32 W[16])
>> +{
>> +       while (blocks--) {
>> +               sm3_transform(sctx, data, W);
>> +               data += SM3_BLOCK_SIZE;
>> +       }
>> +}
>> +
>> +void sm3_update(struct sm3_context *sctx, const uint8_t *input, size_t ilen)
>> +{
>> +       unsigned int partial = sctx->count % SM3_BLOCK_SIZE;
>> +       u32 W[16];
>> +
>> +       sctx->count += ilen;
>> +
>> +       if ((partial + ilen) >= SM3_BLOCK_SIZE) {
>> +               int blocks;
>> +
>> +               if (partial) {
>> +                       int p = SM3_BLOCK_SIZE - partial;
>> +
>> +                       memcpy(sctx->buffer + partial, input, p);
>> +                       input += p;
>> +                       ilen -= p;
>> +
>> +                       sm3_block(sctx, sctx->buffer, 1, W);
>> +               }
>> +
>> +               blocks = ilen / SM3_BLOCK_SIZE;
>> +               ilen %= SM3_BLOCK_SIZE;
>> +
>> +               if (blocks) {
>> +                       sm3_block(sctx, input, blocks, W);
>> +                       input += blocks * SM3_BLOCK_SIZE;
>> +               }
>> +
>> +               memset(W, 0, sizeof(W));
>> +
>> +               partial = 0;
>> +       }
>> +       if (ilen)
>> +               memcpy(sctx->buffer + partial, input, ilen);
>> +}
>> +
>> +void sm3_final(struct sm3_context *sctx, uint8_t output[SM3_DIGEST_SIZE])
> 
> I think it's more readable to just define this as output[]
> [...]

okay, I also change it in sm3_hash()

> 
>> +/**
>> + * sm3_hash - Calculate SM3 hash of input data
>> + * @input: Input data
>> + * @ilen: Input data length in bytes
>> + * @output: Output buffer for hash (32 bytes)
>> + */
>> +void sm3_hash(const uint8_t *input, size_t ilen, uint8_t output[SM3_DIGEST_SIZE])
>> +{
>> +       struct sm3_context sctx;
>> +
>> +       sm3_init(&sctx);
>> +       sm3_update(&sctx, input, ilen);
>> +       sm3_final(&sctx, output);
> 
> Ah ignore my comment on patch #4
> init, update, final is wrapped in this function

Yep, it saves in lib/tpm_tcg2.c tcg2_create_digest() another ifdef
in the variable declaration part.

bye,
Heiko
> 
> [...]
> 
> Thanks
> /Ilias
> 

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