diff options
Diffstat (limited to 'crypto/ansi_cprng.c')
| -rw-r--r-- | crypto/ansi_cprng.c | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c index 72db0fd763c..0fac8ffc2fb 100644 --- a/crypto/ansi_cprng.c +++ b/crypto/ansi_cprng.c @@ -161,7 +161,7 @@ static int _get_more_prng_bytes(struct prng_context *ctx) /* * Now update our DT value */ - for (i = 0; i < DEFAULT_BLK_SZ; i++) { + for (i = DEFAULT_BLK_SZ - 1; i >= 0; i--) { ctx->DT[i] += 1; if (ctx->DT[i] != 0) break; @@ -223,9 +223,10 @@ remainder: } /* - * Copy up to the next whole block size + * Copy any data less than an entire block */ if (byte_count < DEFAULT_BLK_SZ) { +empty_rbuf: for (; ctx->rand_data_valid < DEFAULT_BLK_SZ; ctx->rand_data_valid++) { *ptr = ctx->rand_data[ctx->rand_data_valid]; @@ -240,18 +241,22 @@ remainder: * Now copy whole blocks */ for (; byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) { - if (_get_more_prng_bytes(ctx) < 0) { - memset(buf, 0, nbytes); - err = -EINVAL; - goto done; + if (ctx->rand_data_valid == DEFAULT_BLK_SZ) { + if (_get_more_prng_bytes(ctx) < 0) { + memset(buf, 0, nbytes); + err = -EINVAL; + goto done; + } } + if (ctx->rand_data_valid > 0) + goto empty_rbuf; memcpy(ptr, ctx->rand_data, DEFAULT_BLK_SZ); ctx->rand_data_valid += DEFAULT_BLK_SZ; ptr += DEFAULT_BLK_SZ; } /* - * Now copy any extra partial data + * Now go back and get any remaining partial block */ if (byte_count) goto remainder; @@ -349,15 +354,25 @@ static int cprng_get_random(struct crypto_rng *tfm, u8 *rdata, return get_prng_bytes(rdata, dlen, prng); } +/* + * This is the cprng_registered reset method the seed value is + * interpreted as the tuple { V KEY DT} + * V and KEY are required during reset, and DT is optional, detected + * as being present by testing the length of the seed + */ static int cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen) { struct prng_context *prng = crypto_rng_ctx(tfm); - u8 *key = seed + DEFAULT_PRNG_KSZ; + u8 *key = seed + DEFAULT_BLK_SZ; + u8 *dt = NULL; if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) return -EINVAL; - reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, NULL); + if (slen >= (2 * DEFAULT_BLK_SZ + DEFAULT_PRNG_KSZ)) + dt = key + DEFAULT_PRNG_KSZ; + + reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, dt); if (prng->flags & PRNG_NEED_RESET) return -EINVAL; @@ -379,7 +394,7 @@ static struct crypto_alg rng_alg = { .rng = { .rng_make_random = cprng_get_random, .rng_reset = cprng_reset, - .seedsize = DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ, + .seedsize = DEFAULT_PRNG_KSZ + 2*DEFAULT_BLK_SZ, } } }; |