2016-01-22 08:53:49

by Stephan Mueller

[permalink] [raw]
Subject: [PATCH] crypto: drbg - remove FIPS 140-2 continuous test

Hi,

the following patch is fully CAVS tested on 64 bit and 32 bit.

Note, this change cannot be made for random.c or ansi_cprng.c, unfortunately.

---8<---
The newly released FIPS 140-2 IG 9.8 specifies that for SP800-90A
compliant DRBGs, the FIPS 140-2 continuous random number generator test
is not required any more.

This patch removes the test and all associated data structures.

Signed-off-by: Stephan Mueller <[email protected]>
---
crypto/drbg.c | 64 ---------------------------------------------------
include/crypto/drbg.h | 4 ----
2 files changed, 68 deletions(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index ab6ef1d..1b86310 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -220,48 +220,6 @@ static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
}

/*
- * FIPS 140-2 continuous self test
- * The test is performed on the result of one round of the output
- * function. Thus, the function implicitly knows the size of the
- * buffer.
- *
- * @drbg DRBG handle
- * @buf output buffer of random data to be checked
- *
- * return:
- * true on success
- * false on error
- */
-static bool drbg_fips_continuous_test(struct drbg_state *drbg,
- const unsigned char *buf)
-{
-#ifdef CONFIG_CRYPTO_FIPS
- int ret = 0;
- /* skip test if we test the overall system */
- if (list_empty(&drbg->test_data.list))
- return true;
- /* only perform test in FIPS mode */
- if (0 == fips_enabled)
- return true;
- if (!drbg->fips_primed) {
- /* Priming of FIPS test */
- memcpy(drbg->prev, buf, drbg_blocklen(drbg));
- drbg->fips_primed = true;
- /* return false due to priming, i.e. another round is needed */
- return false;
- }
- ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
- if (!ret)
- panic("DRBG continuous self test failed\n");
- memcpy(drbg->prev, buf, drbg_blocklen(drbg));
- /* the test shall pass when the two compared values are not equal */
- return ret != 0;
-#else
- return true;
-#endif /* CONFIG_CRYPTO_FIPS */
-}
-
-/*
* Convert an integer into a byte representation of this integer.
* The byte representation is big-endian
*
@@ -603,11 +561,6 @@ static int drbg_ctr_generate(struct drbg_state *drbg,
}
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
drbg_blocklen(drbg) : (buflen - len);
- if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
- /* 10.2.1.5.2 step 6 */
- crypto_inc(drbg->V, drbg_blocklen(drbg));
- continue;
- }
/* 10.2.1.5.2 step 4.3 */
memcpy(buf + len, drbg->scratchpad, outlen);
len += outlen;
@@ -733,8 +686,6 @@ static int drbg_hmac_generate(struct drbg_state *drbg,
return ret;
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
drbg_blocklen(drbg) : (buflen - len);
- if (!drbg_fips_continuous_test(drbg, drbg->V))
- continue;

/* 10.1.2.5 step 4.2 */
memcpy(buf + len, drbg->V, outlen);
@@ -963,10 +914,6 @@ static int drbg_hash_hashgen(struct drbg_state *drbg,
}
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
drbg_blocklen(drbg) : (buflen - len);
- if (!drbg_fips_continuous_test(drbg, dst)) {
- crypto_inc(src, drbg_statelen(drbg));
- continue;
- }
/* 10.1.1.4 step hashgen 4.2 */
memcpy(buf + len, dst, outlen);
len += outlen;
@@ -1201,11 +1148,6 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
drbg->reseed_ctr = 0;
drbg->d_ops = NULL;
drbg->core = NULL;
-#ifdef CONFIG_CRYPTO_FIPS
- kzfree(drbg->prev);
- drbg->prev = NULL;
- drbg->fips_primed = false;
-#endif
}

/*
@@ -1244,12 +1186,6 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
if (!drbg->C)
goto err;
-#ifdef CONFIG_CRYPTO_FIPS
- drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
- if (!drbg->prev)
- goto err;
- drbg->fips_primed = false;
-#endif
/* scratchpad is only generated for CTR and Hash */
if (drbg->core->flags & DRBG_HMAC)
sb_size = 0;
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index 9756c70..d961b2b 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -117,10 +117,6 @@ struct drbg_state {
void *priv_data; /* Cipher handle */
bool seeded; /* DRBG fully seeded? */
bool pr; /* Prediction resistance enabled? */
-#ifdef CONFIG_CRYPTO_FIPS
- bool fips_primed; /* Continuous test primed? */
- unsigned char *prev; /* FIPS 140-2 continuous test value */
-#endif
struct work_struct seed_work; /* asynchronous seeding support */
struct crypto_rng *jent;
const struct drbg_state_ops *d_ops;
--
2.5.0


2016-01-25 14:49:34

by Herbert Xu

[permalink] [raw]
Subject: Re: [PATCH] crypto: drbg - remove FIPS 140-2 continuous test

On Fri, Jan 22, 2016 at 09:52:28AM +0100, Stephan Mueller wrote:
> Hi,
>
> the following patch is fully CAVS tested on 64 bit and 32 bit.
>
> Note, this change cannot be made for random.c or ansi_cprng.c, unfortunately.
>
> ---8<---
> The newly released FIPS 140-2 IG 9.8 specifies that for SP800-90A
> compliant DRBGs, the FIPS 140-2 continuous random number generator test
> is not required any more.
>
> This patch removes the test and all associated data structures.
>
> Signed-off-by: Stephan Mueller <[email protected]>

Applied.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt