Re: [PATCH v2 5/6] crypto/fsl: instantiate the RNG with prediciton resistance

On 6/4/2020 6:48 PM, Michael Walle wrote:

+static int deinstantiate_rng(u8 sec_idx, int state_handle_mask) +{

• u32 *desc;
• int sh_idx, ret = 0;
• int desc_size = sizeof(u32) * 3;

As you mentioned, descriptor size should be sizeof(u32) * 2.

• desc = memalign(ARCH_DMA_MINALIGN, desc_size);
• if (!desc) {

• debug("cannot allocate RNG init descriptor memory\n");
  

• return -ENOMEM;
  

• }
• for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {

• /*
  

•  * If the corresponding bit is set, then it means the state
  

•  * handle was initialized by us, and thus it needs to be
  

•  * deinitialized as well
  

•  */
  

• if (state_handle_mask & RDSTA_IF(sh_idx)) {
  

• 	/*
  

• 	 * Create the descriptor for deinstantating this state
  

• 	 * handle.
  

• 	 */
  

• 	inline_cnstr_jobdesc_rng_deinstantiation(desc, sh_idx);
  

• 	flush_dcache_range((unsigned long)desc,
  

• 			   (unsigned long)desc + desc_size);
  

Shouldn't this be roundup(desc_size, ARCH_DMA_MINALIGN) instead of desc_size?

@@ -466,9 +511,18 @@ static int instantiate_rng(u8 sec_idx, int gen_sk) * If the corresponding bit is set, this state handle * was initialized by somebody else, so it's left alone. */

• rdsta_val = sec_in32(&rng->rdsta) & RNG_STATE_HANDLE_MASK;
  

• if (rdsta_val & (1 << sh_idx))
  

• 	continue;
  

• rdsta_val = sec_in32(&rng->rdsta);
  

• if (rdsta_val & (RDSTA_IF(sh_idx) | RDSTA_PR(sh_idx))) {
  

Adding RDSTA_PR(sh_idx) to the mask is not needed, PR bit is meaningless without IF bit set.

• 	if (rdsta_val & RDSTA_PR(sh_idx))
  

• 		continue;
  

Could combine the condition here with the outer if condition: if (rdsta_val & RDSTA_IF(sh_idx) && !(rdsta_val & RDSTA_PR(sh_idx))) {

• 	printf("SEC%u:  RNG4 SH%d was instantiated w/o prediction resistance. Tearing it down\n",
  

• 	       sec_idx, sh_idx);
  

• 	ret = deinstantiate_rng(sec_idx, RDSTA_IF(sh_idx));
  

• 	if (ret)
  

• 		break;
  

• }
  

Horia