rand: add a provider side seed source.

This allows the operating system sources that OpenSSL supports to be
used directly as RNGs.  It also allows DRBG seeding to be explicitly
specified rather than being left to a fall back case.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13455)

6 files changed, 198 insertions, 1 deletions

diff --git a/providers/common/include/prov/providercommonerr.h b/providers/common/include/prov/providercommonerr.h
index ad1bd20c53..f044e7b7c7 100644
--- a/providers/common/include/prov/providercommonerr.h
+++ b/providers/common/include/prov/providercommonerr.h
@@ -154,6 +154,7 @@ int err_load_PROV_strings_int(void);
 # define PROV_R_REQUIRE_CTR_MODE_CIPHER                   206
 # define PROV_R_RESEED_ERROR                              197
 # define PROV_R_SEARCH_ONLY_SUPPORTED_FOR_DIRECTORIES     222
+# define PROV_R_SEED_SOURCES_MUST_NOT_HAVE_A_PARENT       200
 # define PROV_R_SELF_TEST_KAT_FAILURE                     215
 # define PROV_R_SELF_TEST_POST_FAILURE                    216
 # define PROV_R_TAG_NOTSET                                119
diff --git a/providers/common/provider_err.c b/providers/common/provider_err.c
index fed6018387..3a28eaaa2d 100644
--- a/providers/common/provider_err.c
+++ b/providers/common/provider_err.c
@@ -175,6 +175,8 @@ static const ERR_STRING_DATA PROV_str_reasons[] = {
     {ERR_PACK(ERR_LIB_PROV, 0, PROV_R_RESEED_ERROR), "reseed error"},
     {ERR_PACK(ERR_LIB_PROV, 0, PROV_R_SEARCH_ONLY_SUPPORTED_FOR_DIRECTORIES),
     "search only supported for directories"},
+    {ERR_PACK(ERR_LIB_PROV, 0, PROV_R_SEED_SOURCES_MUST_NOT_HAVE_A_PARENT),
+    "seed sources must not have a parent"},
     {ERR_PACK(ERR_LIB_PROV, 0, PROV_R_SELF_TEST_KAT_FAILURE),
     "self test kat failure"},
     {ERR_PACK(ERR_LIB_PROV, 0, PROV_R_SELF_TEST_POST_FAILURE),
diff --git a/providers/defltprov.c b/providers/defltprov.c
index 9a662738d8..3cd7dffee8 100644
--- a/providers/defltprov.c
+++ b/providers/defltprov.c
@@ -362,6 +362,7 @@ static const OSSL_ALGORITHM deflt_rands[] = {
     { "CTR-DRBG", "provider=default", ossl_drbg_ctr_functions },
     { "HASH-DRBG", "provider=default", ossl_drbg_hash_functions },
     { "HMAC-DRBG", "provider=default", ossl_drbg_ossl_hmac_functions },
+    { "SEED-SRC", "provider=default", ossl_seed_src_functions },
     { "TEST-RAND", "provider=default", ossl_test_rng_functions },
     { NULL, NULL, NULL }
 };
diff --git a/providers/implementations/include/prov/implementations.h b/providers/implementations/include/prov/implementations.h
index 00178d4ceb..5b6f913131 100644
--- a/providers/implementations/include/prov/implementations.h
+++ b/providers/implementations/include/prov/implementations.h
@@ -265,6 +265,7 @@ extern const OSSL_DISPATCH ossl_kdf_krb5kdf_functions[];
 
 /* RNGs */
 extern const OSSL_DISPATCH ossl_test_rng_functions[];
+extern const OSSL_DISPATCH ossl_seed_src_functions[];
 extern const OSSL_DISPATCH ossl_drbg_hash_functions[];
 extern const OSSL_DISPATCH ossl_drbg_ossl_hmac_functions[];
 extern const OSSL_DISPATCH ossl_drbg_ctr_functions[];
diff --git a/providers/implementations/rands/build.info b/providers/implementations/rands/build.info
index 2ca0cdadc7..b44c1caa8a 100644
--- a/providers/implementations/rands/build.info
+++ b/providers/implementations/rands/build.info
@@ -3,4 +3,4 @@ SUBDIRS=seeding
 $COMMON=drbg.c test_rng.c drbg_ctr.c drbg_hash.c drbg_hmac.c crngt.c
 
 SOURCE[../../libfips.a]=$COMMON
-SOURCE[../../libnonfips.a]=$COMMON
+SOURCE[../../libnonfips.a]=$COMMON seed_src.c
diff --git a/providers/implementations/rands/seed_src.c b/providers/implementations/rands/seed_src.c
new file mode 100644
index 0000000000..7080e95fbf
--- /dev/null
+++ b/providers/implementations/rands/seed_src.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <string.h>
+#include <openssl/rand.h>
+#include <openssl/core_dispatch.h>
+#include <openssl/e_os2.h>
+#include <openssl/params.h>
+#include <openssl/core_names.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include <openssl/randerr.h>
+#include "prov/implementations.h"
+#include "prov/provider_ctx.h"
+#include "prov/providercommonerr.h"
+#include "crypto/rand.h"
+#include "crypto/rand_pool.h"
+
+static OSSL_FUNC_rand_newctx_fn seed_src_new;
+static OSSL_FUNC_rand_freectx_fn seed_src_free;
+static OSSL_FUNC_rand_instantiate_fn seed_src_instantiate;
+static OSSL_FUNC_rand_uninstantiate_fn seed_src_uninstantiate;
+static OSSL_FUNC_rand_generate_fn seed_src_generate;
+static OSSL_FUNC_rand_reseed_fn seed_src_reseed;
+static OSSL_FUNC_rand_gettable_ctx_params_fn seed_src_gettable_ctx_params;
+static OSSL_FUNC_rand_get_ctx_params_fn seed_src_get_ctx_params;
+static OSSL_FUNC_rand_verify_zeroization_fn seed_src_verify_zeroization;
+static OSSL_FUNC_rand_enable_locking_fn seed_src_enable_locking;
+
+typedef struct {
+    void *provctx;
+    int state;
+} PROV_SEED_SRC;
+
+static void *seed_src_new(void *provctx, void *parent,
+                          const OSSL_DISPATCH *parent_dispatch)
+{
+    PROV_SEED_SRC *s;
+
+    if (parent != NULL) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_SEED_SOURCES_MUST_NOT_HAVE_A_PARENT);
+        return NULL;
+    }
+
+    s = OPENSSL_zalloc(sizeof(*s));
+    if (s == NULL) {
+        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+
+    s->provctx = provctx;
+    s->state = EVP_RAND_STATE_UNINITIALISED;
+    return s;
+}
+
+static void seed_src_free(void *vseed)
+{
+    OPENSSL_free(vseed);
+}
+
+static int seed_src_instantiate(void *vseed, unsigned int strength,
+                                int prediction_resistance,
+                                const unsigned char *pstr, size_t pstr_len)
+{
+    PROV_SEED_SRC *s = (PROV_SEED_SRC *)vseed;
+
+    s->state = EVP_RAND_STATE_READY;
+    return 1;
+}
+
+static int seed_src_uninstantiate(void *vseed)
+{
+    PROV_SEED_SRC *s = (PROV_SEED_SRC *)vseed;
+
+    s->state = EVP_RAND_STATE_UNINITIALISED;
+    return 1;
+}
+
+static int seed_src_generate(void *vseed, unsigned char *out, size_t outlen,
+                             unsigned int strength,
+                             ossl_unused int prediction_resistance,
+                             ossl_unused const unsigned char *adin,
+                             ossl_unused size_t adin_len)
+{
+    PROV_SEED_SRC *s = (PROV_SEED_SRC *)vseed;
+    size_t entropy_available;
+    RAND_POOL *pool;
+
+    if (s->state != EVP_RAND_STATE_READY) {
+        ERR_raise(ERR_LIB_PROV,
+                  s->state == EVP_RAND_STATE_ERROR ? PROV_R_IN_ERROR_STATE
+                                                   : PROV_R_NOT_INSTANTIATED);
+        return 0;
+    }
+
+    pool = rand_pool_new(strength, 1, outlen, outlen);
+    if (pool == NULL) {
+        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+
+    /* Get entropy by polling system entropy sources. */
+    entropy_available = ossl_pool_acquire_entropy(pool);
+
+    if (entropy_available > 0)
+        memcpy(out, rand_pool_detach(pool), rand_pool_length(pool));
+
+    rand_pool_free(pool);
+    return entropy_available > 0;
+}
+
+static int seed_src_reseed(void *vseed,
+                           ossl_unused int prediction_resistance,
+                           ossl_unused const unsigned char *ent,
+                           ossl_unused size_t ent_len,
+                           ossl_unused const unsigned char *adin,
+                           ossl_unused size_t adin_len)
+{
+    PROV_SEED_SRC *s = (PROV_SEED_SRC *)vseed;
+
+    if (s->state != EVP_RAND_STATE_READY) {
+        ERR_raise(ERR_LIB_PROV,
+                  s->state == EVP_RAND_STATE_ERROR ? PROV_R_IN_ERROR_STATE
+                                                   : PROV_R_NOT_INSTANTIATED);
+        return 0;
+    }
+    return 1;
+}
+
+static int seed_src_get_ctx_params(void *vseed, OSSL_PARAM params[])
+{
+    PROV_SEED_SRC *s = (PROV_SEED_SRC *)vseed;
+    OSSL_PARAM *p;
+
+    p = OSSL_PARAM_locate(params, OSSL_RAND_PARAM_STATE);
+    if (p != NULL && !OSSL_PARAM_set_int(p, s->state))
+        return 0;
+
+    p = OSSL_PARAM_locate(params, OSSL_RAND_PARAM_STRENGTH);
+    if (p != NULL && !OSSL_PARAM_set_int(p, 1024))
+        return 0;
+
+    p = OSSL_PARAM_locate(params, OSSL_RAND_PARAM_MAX_REQUEST);
+    if (p != NULL && !OSSL_PARAM_set_size_t(p, 128))
+        return 0;
+    return 1;
+}
+
+static const OSSL_PARAM *seed_src_gettable_ctx_params(ossl_unused void *provctx)
+{
+    static const OSSL_PARAM known_gettable_ctx_params[] = {
+        OSSL_PARAM_int(OSSL_RAND_PARAM_STATE, NULL),
+        OSSL_PARAM_uint(OSSL_RAND_PARAM_STRENGTH, NULL),
+        OSSL_PARAM_size_t(OSSL_RAND_PARAM_MAX_REQUEST, NULL),
+        OSSL_PARAM_END
+    };
+    return known_gettable_ctx_params;
+}
+
+static int seed_src_verify_zeroization(ossl_unused void *vseed)
+{
+    return 1;
+}
+
+static int seed_src_enable_locking(ossl_unused void *vseed)
+{
+    return 1;
+}
+
+const OSSL_DISPATCH ossl_seed_src_functions[] = {
+    { OSSL_FUNC_RAND_NEWCTX, (void(*)(void))seed_src_new },
+    { OSSL_FUNC_RAND_FREECTX, (void(*)(void))seed_src_free },
+    { OSSL_FUNC_RAND_INSTANTIATE,
+      (void(*)(void))seed_src_instantiate },
+    { OSSL_FUNC_RAND_UNINSTANTIATE,
+      (void(*)(void))seed_src_uninstantiate },
+    { OSSL_FUNC_RAND_GENERATE, (void(*)(void))seed_src_generate },
+    { OSSL_FUNC_RAND_RESEED, (void(*)(void))seed_src_reseed },
+    { OSSL_FUNC_RAND_ENABLE_LOCKING, (void(*)(void))seed_src_enable_locking },
+    { OSSL_FUNC_RAND_GETTABLE_CTX_PARAMS,
+      (void(*)(void))seed_src_gettable_ctx_params },
+    { OSSL_FUNC_RAND_GET_CTX_PARAMS, (void(*)(void))seed_src_get_ctx_params },
+    { OSSL_FUNC_RAND_VERIFY_ZEROIZATION,
+      (void(*)(void))seed_src_verify_zeroization },
+    { 0, NULL }
+};