AES CTR-DRGB: do not leak timing information
*/
static void inc_128(RAND_DRBG_CTR *ctr)
{
- int i;
- unsigned char c;
- unsigned char *p = &ctr->V[15];
-
- for (i = 0; i < 16; i++, p--) {
- c = *p;
- c++;
- *p = c;
- if (c != 0) {
- /* If we didn't wrap around, we're done. */
- break;
- }
- }
+ unsigned char *p = &ctr->V[0];
+ u32 n = 16, c = 1;
+
+ do {
+ --n;
+ c += p[n];
+ p[n] = (u8)c;
+ c >>= 8;
+ } while (n);
}
static void ctr_XOR(RAND_DRBG_CTR *ctr, const unsigned char *in, size_t inlen)
