crypto: drbg - Convert to new rng interface

This patch converts the DRBG implementation to the new low-level
rng interface.

This allows us to get rid of struct drbg_gen by using the new RNG
API instead.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stephan Mueller <smueller@chronox.de>

2 files changed, 66 insertions, 107 deletions

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 5bce15918de5..ec6bffd77001 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -235,7 +235,7 @@ static bool drbg_fips_continuous_test(struct drbg_state *drbg,
 #ifdef CONFIG_CRYPTO_FIPS
         int ret = 0;
         /* skip test if we test the overall system */
-        if (drbg->test_data)
+        if (list_empty(&drbg->test_data.list))
                 return true;
         /* only perform test in FIPS mode */
         if (0 == fips_enabled)
@@ -1068,9 +1068,9 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
                 return -EINVAL;
         }
 
-        if (drbg->test_data && drbg->test_data->testentropy) {
-                drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
-                                 drbg->test_data->testentropy->len);
+        if (list_empty(&drbg->test_data.list)) {
+                drbg_string_fill(&data1, drbg->test_data.buf,
+                                 drbg->test_data.len);
                 pr_devel("DRBG: using test entropy\n");
         } else {
                 /*
@@ -1471,15 +1471,16 @@ static int drbg_uninstantiate(struct drbg_state *drbg)
  * Helper function for setting the test data in the DRBG
  *
  * @drbg DRBG state handle
- * @test_data test data to sets
+ * @data test data
+ * @len test data length
  */
-static inline void drbg_set_testdata(struct drbg_state *drbg,
-                                     struct drbg_test_data *test_data)
+static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
+                                   const u8 *data, unsigned int len)
 {
-        if (!test_data || !test_data->testentropy)
-                return;
-        mutex_lock(&drbg->drbg_mutex);;
-        drbg->test_data = test_data;
+        struct drbg_state *drbg = crypto_rng_ctx(tfm);
+
+        mutex_lock(&drbg->drbg_mutex);
+        drbg_string_fill(&drbg->test_data, data, len);
         mutex_unlock(&drbg->drbg_mutex);
 }
 
@@ -1645,63 +1646,49 @@ static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
  * Generate random numbers invoked by the kernel crypto API:
  * The API of the kernel crypto API is extended as follows:
  *
- * If dlen is larger than zero, rdata is interpreted as the output buffer
- * where random data is to be stored.
- *
- * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
- * which holds the additional information string that is used for the
- * DRBG generation process. The output buffer that is to be used to store
- * data is also pointed to by struct drbg_gen.
+ * src is additional input supplied to the RNG.
+ * slen is the length of src.
+ * dst is the output buffer where random data is to be stored.
+ * dlen is the length of dst.
  */
-static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
-                             unsigned int dlen)
+static int drbg_kcapi_random(struct crypto_rng *tfm,
+                             const u8 *src, unsigned int slen,
+                             u8 *dst, unsigned int dlen)
 {
         struct drbg_state *drbg = crypto_rng_ctx(tfm);
-        if (0 < dlen) {
-                return drbg_generate_long(drbg, rdata, dlen, NULL);
-        } else {
-                struct drbg_gen *data = (struct drbg_gen *)rdata;
-                struct drbg_string addtl;
-                /* catch NULL pointer */
-                if (!data)
-                        return 0;
-                drbg_set_testdata(drbg, data->test_data);
+        struct drbg_string *addtl = NULL;
+        struct drbg_string string;
+
+        if (slen) {
                 /* linked list variable is now local to allow modification */
-                drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
-                return drbg_generate_long(drbg, data->outbuf, data->outlen,
-                                          &addtl);
+                drbg_string_fill(&string, src, slen);
+                addtl = &string;
         }
+
+        return drbg_generate_long(drbg, dst, dlen, addtl);
 }
 
 /*
  * Seed the DRBG invoked by the kernel crypto API
- * Similar to the generate function of drbg_kcapi_random, this
- * function extends the kernel crypto API interface with struct drbg_gen
  */
-static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
+static int drbg_kcapi_seed(struct crypto_rng *tfm,
+                           const u8 *seed, unsigned int slen)
 {
         struct drbg_state *drbg = crypto_rng_ctx(tfm);
         struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
         bool pr = false;
-        struct drbg_string seed_string;
+        struct drbg_string string;
+        struct drbg_string *seed_string = NULL;
         int coreref = 0;
 
         drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
                               &pr);
         if (0 < slen) {
-                drbg_string_fill(&seed_string, seed, slen);
-                return drbg_instantiate(drbg, &seed_string, coreref, pr);
-        } else {
-                struct drbg_gen *data = (struct drbg_gen *)seed;
-                /* allow invocation of API call with NULL, 0 */
-                if (!data)
-                        return drbg_instantiate(drbg, NULL, coreref, pr);
-                drbg_set_testdata(drbg, data->test_data);
-                /* linked list variable is now local to allow modification */
-                drbg_string_fill(&seed_string, data->addtl->buf,
-                                 data->addtl->len);
-                return drbg_instantiate(drbg, &seed_string, coreref, pr);
+                drbg_string_fill(&string, seed, slen);
+                seed_string = &string;
         }
+
+        return drbg_instantiate(drbg, seed_string, coreref, pr);
 }
 
 /***************************************************************
@@ -1793,32 +1780,31 @@ outbuf:
 #endif /* CONFIG_CRYPTO_FIPS */
 }
 
-static struct crypto_alg drbg_algs[22];
+static struct rng_alg drbg_algs[22];
 
 /*
  * Fill the array drbg_algs used to register the different DRBGs
  * with the kernel crypto API. To fill the array, the information
  * from drbg_cores[] is used.
  */
-static inline void __init drbg_fill_array(struct crypto_alg *alg,
+static inline void __init drbg_fill_array(struct rng_alg *alg,
                                           const struct drbg_core *core, int pr)
 {
         int pos = 0;
         static int priority = 100;
 
-        memset(alg, 0, sizeof(struct crypto_alg));
-        memcpy(alg->cra_name, "stdrng", 6);
+        memcpy(alg->base.cra_name, "stdrng", 6);
         if (pr) {
-                memcpy(alg->cra_driver_name, "drbg_pr_", 8);
+                memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
                 pos = 8;
         } else {
-                memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
+                memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
                 pos = 10;
         }
-        memcpy(alg->cra_driver_name + pos, core->cra_name,
+        memcpy(alg->base.cra_driver_name + pos, core->cra_name,
                strlen(core->cra_name));
 
-        alg->cra_priority = priority;
+        alg->base.cra_priority = priority;
         priority++;
         /*
          * If FIPS mode enabled, the selected DRBG shall have the
@@ -1826,17 +1812,16 @@ static inline void __init drbg_fill_array(struct crypto_alg *alg,
          * it is selected.
          */
         if (fips_enabled)
-                alg->cra_priority += 200;
-
-        alg->cra_flags          = CRYPTO_ALG_TYPE_RNG;
-        alg->cra_ctxsize        = sizeof(struct drbg_state);
-        alg->cra_type           = &crypto_rng_type;
-        alg->cra_module         = THIS_MODULE;
-        alg->cra_init           = drbg_kcapi_init;
-        alg->cra_exit           = drbg_kcapi_cleanup;
-        alg->cra_u.rng.rng_make_random  = drbg_kcapi_random;
-        alg->cra_u.rng.rng_reset        = drbg_kcapi_reset;
-        alg->cra_u.rng.seedsize = 0;
+                alg->base.cra_priority += 200;
+
+        alg->base.cra_ctxsize   = sizeof(struct drbg_state);
+        alg->base.cra_module    = THIS_MODULE;
+        alg->base.cra_init      = drbg_kcapi_init;
+        alg->base.cra_exit      = drbg_kcapi_cleanup;
+        alg->generate           = drbg_kcapi_random;
+        alg->seed               = drbg_kcapi_seed;
+        alg->set_ent            = drbg_kcapi_set_entropy;
+        alg->seedsize           = 0;
 }
 
 static int __init drbg_init(void)
@@ -1869,12 +1854,12 @@ static int __init drbg_init(void)
                 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
         for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
                 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
-        return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
+        return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
 }
 
 static void __exit drbg_exit(void)
 {
-        crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
+        crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
 }
 
 module_init(drbg_init);
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index a43a7ed4d9fc..480d7a0f4dac 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -121,7 +121,7 @@ struct drbg_state {
 #endif
         const struct drbg_state_ops *d_ops;
         const struct drbg_core *core;
-        struct drbg_test_data *test_data;
+        struct drbg_string test_data;
 };
 
 static inline __u8 drbg_statelen(struct drbg_state *drbg)
@@ -177,19 +177,8 @@ static inline size_t drbg_max_requests(struct drbg_state *drbg)
 }
 
 /*
- * kernel crypto API input data structure for DRBG generate in case dlen
- * is set to 0
- */
-struct drbg_gen {
-        unsigned char *outbuf;  /* output buffer for random numbers */
-        unsigned int outlen;    /* size of output buffer */
-        struct drbg_string *addtl;      /* additional information string */
-        struct drbg_test_data *test_data;       /* test data */
-};
-
-/*
  * This is a wrapper to the kernel crypto API function of
- * crypto_rng_get_bytes() to allow the caller to provide additional data.
+ * crypto_rng_generate() to allow the caller to provide additional data.
  *
  * @drng DRBG handle -- see crypto_rng_get_bytes
  * @outbuf output buffer -- see crypto_rng_get_bytes
@@ -204,21 +193,15 @@ static inline int crypto_drbg_get_bytes_addtl(struct crypto_rng *drng,
                         unsigned char *outbuf, unsigned int outlen,
                         struct drbg_string *addtl)
 {
-        int ret;
-        struct drbg_gen genbuf;
-        genbuf.outbuf = outbuf;
-        genbuf.outlen = outlen;
-        genbuf.addtl = addtl;
-        genbuf.test_data = NULL;
-        ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
-        return ret;
+        return crypto_rng_generate(drng, addtl->buf, addtl->len,
+                                   outbuf, outlen);
 }
 
 /*
  * TEST code
  *
  * This is a wrapper to the kernel crypto API function of
- * crypto_rng_get_bytes() to allow the caller to provide additional data and
+ * crypto_rng_generate() to allow the caller to provide additional data and
  * allow furnishing of test_data
  *
  * @drng DRBG handle -- see crypto_rng_get_bytes
@@ -236,14 +219,10 @@ static inline int crypto_drbg_get_bytes_addtl_test(struct crypto_rng *drng,
                         struct drbg_string *addtl,
                         struct drbg_test_data *test_data)
 {
-        int ret;
-        struct drbg_gen genbuf;
-        genbuf.outbuf = outbuf;
-        genbuf.outlen = outlen;
-        genbuf.addtl = addtl;
-        genbuf.test_data = test_data;
-        ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
-        return ret;
+        crypto_rng_set_entropy(drng, test_data->testentropy->buf,
+                               test_data->testentropy->len);
+        return crypto_rng_generate(drng, addtl->buf, addtl->len,
+                                   outbuf, outlen);
 }
 
 /*
@@ -264,14 +243,9 @@ static inline int crypto_drbg_reset_test(struct crypto_rng *drng,
                                          struct drbg_string *pers,
                                          struct drbg_test_data *test_data)
 {
-        int ret;
-        struct drbg_gen genbuf;
-        genbuf.outbuf = NULL;
-        genbuf.outlen = 0;
-        genbuf.addtl = pers;
-        genbuf.test_data = test_data;
-        ret = crypto_rng_reset(drng, (u8 *)&genbuf, 0);
-        return ret;
+        crypto_rng_set_entropy(drng, test_data->testentropy->buf,
+                               test_data->testentropy->len);
+        return crypto_rng_reset(drng, pers->buf, pers->len);
 }
 
 /* DRBG type flags */