crypto: ansi_cprng - Add FIPS wrapper

Patch to add fips(ansi_cprng) alg, which is ansi_cprng plus a continuous test

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 70 insertions, 9 deletions

diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c
index 3aa6e3834bfe..027176a0e889 100644
--- a/crypto/ansi_cprng.c
+++ b/crypto/ansi_cprng.c
@@ -85,7 +85,7 @@ static void xor_vectors(unsigned char *in1, unsigned char *in2,
  * Returns DEFAULT_BLK_SZ bytes of random data per call
  * returns 0 if generation succeded, <0 if something went wrong
  */
-static int _get_more_prng_bytes(struct prng_context *ctx)
+static int _get_more_prng_bytes(struct prng_context *ctx, int cont_test)
 {
         int i;
         unsigned char tmp[DEFAULT_BLK_SZ];
@@ -132,7 +132,7 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
                          */
                         if (!memcmp(ctx->rand_data, ctx->last_rand_data,
                                         DEFAULT_BLK_SZ)) {
-                                if (fips_enabled) {
+                                if (cont_test) {
                                         panic("cprng %p Failed repetition check!\n",
                                                 ctx);
                                 }
@@ -185,7 +185,8 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
 }
 
 /* Our exported functions */
-static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx)
+static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx,
+                                int do_cont_test)
 {
         unsigned char *ptr = buf;
         unsigned int byte_count = (unsigned int)nbytes;
@@ -220,7 +221,7 @@ static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx)
 
 remainder:
         if (ctx->rand_data_valid == DEFAULT_BLK_SZ) {
-                if (_get_more_prng_bytes(ctx) < 0) {
+                if (_get_more_prng_bytes(ctx, do_cont_test) < 0) {
                         memset(buf, 0, nbytes);
                         err = -EINVAL;
                         goto done;
@@ -247,7 +248,7 @@ empty_rbuf:
          */
         for (; byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) {
                 if (ctx->rand_data_valid == DEFAULT_BLK_SZ) {
-                        if (_get_more_prng_bytes(ctx) < 0) {
+                        if (_get_more_prng_bytes(ctx, do_cont_test) < 0) {
                                 memset(buf, 0, nbytes);
                                 err = -EINVAL;
                                 goto done;
@@ -356,7 +357,15 @@ static int cprng_get_random(struct crypto_rng *tfm, u8 *rdata,
 {
         struct prng_context *prng = crypto_rng_ctx(tfm);
 
-        return get_prng_bytes(rdata, dlen, prng);
+        return get_prng_bytes(rdata, dlen, prng, 0);
+}
+
+static int fips_cprng_get_random(struct crypto_rng *tfm, u8 *rdata,
+                            unsigned int dlen)
+{
+        struct prng_context *prng = crypto_rng_ctx(tfm);
+
+        return get_prng_bytes(rdata, dlen, prng, 1);
 }
 
 /*
@@ -384,6 +393,26 @@ static int cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
         return 0;
 }
 
+static int fips_cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
+{
+        u8 rdata[DEFAULT_BLK_SZ];
+        int rc;
+
+        struct prng_context *prng = crypto_rng_ctx(tfm);
+
+        rc = cprng_reset(tfm, seed, slen);
+
+        if (!rc)
+                goto out;
+
+        /* this primes our continuity test */
+        rc = get_prng_bytes(rdata, DEFAULT_BLK_SZ, prng, 0);
+        prng->rand_data_valid = DEFAULT_BLK_SZ;
+
+out:
+        return rc;
+}
+
 static struct crypto_alg rng_alg = {
         .cra_name               = "stdrng",
         .cra_driver_name        = "ansi_cprng",
@@ -404,19 +433,51 @@ static struct crypto_alg rng_alg = {
         }
 };
 
+#ifdef CONFIG_CRYPTO_FIPS
+static struct crypto_alg fips_rng_alg = {
+        .cra_name               = "fips(ansi_cprng)",
+        .cra_driver_name        = "fips_ansi_cprng",
+        .cra_priority           = 300,
+        .cra_flags              = CRYPTO_ALG_TYPE_RNG,
+        .cra_ctxsize            = sizeof(struct prng_context),
+        .cra_type               = &crypto_rng_type,
+        .cra_module             = THIS_MODULE,
+        .cra_list               = LIST_HEAD_INIT(rng_alg.cra_list),
+        .cra_init               = cprng_init,
+        .cra_exit               = cprng_exit,
+        .cra_u                  = {
+                .rng = {
+                        .rng_make_random        = fips_cprng_get_random,
+                        .rng_reset              = fips_cprng_reset,
+                        .seedsize = DEFAULT_PRNG_KSZ + 2*DEFAULT_BLK_SZ,
+                }
+        }
+};
+#endif
 
 /* Module initalization */
 static int __init prng_mod_init(void)
 {
-        if (fips_enabled)
-                rng_alg.cra_priority += 200;
+        int rc = 0;
 
-        return crypto_register_alg(&rng_alg);
+        rc = crypto_register_alg(&rng_alg);
+#ifdef CONFIG_CRYPTO_FIPS
+        if (rc)
+                goto out;
+
+        rc = crypto_register_alg(&fips_rng_alg);
+
+out:
+#endif
+        return rc;
 }
 
 static void __exit prng_mod_fini(void)
 {
         crypto_unregister_alg(&rng_alg);
+#ifdef CONFIG_CRYPTO_FIPS
+        crypto_unregister_alg(&fips_rng_alg);
+#endif
         return;
 }