CRNGT: continuous DRBG tests for providers
[openssl.git] / crypto / rand / rand_lib.c
index 238712671ba3d4ba568e0ef1ab0c5e5210dfae00..a4c9e694726e749f7ce981364f192f0086d85b17 100644 (file)
@@ -1,7 +1,7 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
  *
- * Licensed under the OpenSSL license (the "License").  You may not use
+ * 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 <time.h>
 #include "internal/cryptlib.h"
 #include <openssl/opensslconf.h>
-#include "internal/rand.h"
-
+#include "crypto/rand.h"
 #include <openssl/engine.h>
+#include "internal/thread_once.h"
+#include "rand_local.h"
+#include "e_os.h"
+
+#ifndef FIPS_MODULE
+# ifndef OPENSSL_NO_ENGINE
+/* non-NULL if default_RAND_meth is ENGINE-provided */
+static ENGINE *funct_ref;
+static CRYPTO_RWLOCK *rand_engine_lock;
+# endif
+static CRYPTO_RWLOCK *rand_meth_lock;
+static const RAND_METHOD *default_RAND_meth;
+static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
 
-#ifdef OPENSSL_FIPS
-# include <openssl/fips.h>
-# include <openssl/fips_rand.h>
+static int rand_inited = 0;
+#endif /* FIPS_MODULE */
+
+#ifdef OPENSSL_RAND_SEED_RDTSC
+/*
+ * IMPORTANT NOTE:  It is not currently possible to use this code
+ * because we are not sure about the amount of randomness it provides.
+ * Some SP900 tests have been run, but there is internal skepticism.
+ * So for now this code is not used.
+ */
+# error "RDTSC enabled?  Should not be possible!"
+
+/*
+ * Acquire entropy from high-speed clock
+ *
+ * Since we get some randomness from the low-order bits of the
+ * high-speed clock, it can help.
+ *
+ * Returns the total entropy count, if it exceeds the requested
+ * entropy count. Otherwise, returns an entropy count of 0.
+ */
+size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
+{
+    unsigned char c;
+    int i;
+
+    if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
+        for (i = 0; i < TSC_READ_COUNT; i++) {
+            c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
+            rand_pool_add(pool, &c, 1, 4);
+        }
+    }
+    return rand_pool_entropy_available(pool);
+}
 #endif
 
-#ifndef OPENSSL_NO_ENGINE
-/* non-NULL if default_RAND_meth is ENGINE-provided */
-static ENGINE *funct_ref = NULL;
+#ifdef OPENSSL_RAND_SEED_RDCPU
+size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
+size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
+
+/*
+ * Acquire entropy using Intel-specific cpu instructions
+ *
+ * Uses the RDSEED instruction if available, otherwise uses
+ * RDRAND if available.
+ *
+ * For the differences between RDSEED and RDRAND, and why RDSEED
+ * is the preferred choice, see https://goo.gl/oK3KcN
+ *
+ * Returns the total entropy count, if it exceeds the requested
+ * entropy count. Otherwise, returns an entropy count of 0.
+ */
+size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
+{
+    size_t bytes_needed;
+    unsigned char *buffer;
+
+    bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+    if (bytes_needed > 0) {
+        buffer = rand_pool_add_begin(pool, bytes_needed);
+
+        if (buffer != NULL) {
+            /* Whichever comes first, use RDSEED, RDRAND or nothing */
+            if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
+                if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
+                    == bytes_needed) {
+                    rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
+                }
+            } else if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
+                if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
+                    == bytes_needed) {
+                    rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
+                }
+            } else {
+                rand_pool_add_end(pool, 0, 0);
+            }
+        }
+    }
+
+    return rand_pool_entropy_available(pool);
+}
+#endif
+
+#if 0
+/*
+ * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ * If the DRBG has a parent, then the required amount of entropy input
+ * is fetched using the parent's RAND_DRBG_generate().
+ *
+ * Otherwise, the entropy is polled from the system entropy sources
+ * using rand_pool_acquire_entropy().
+ *
+ * If a random pool has been added to the DRBG using RAND_add(), then
+ * its entropy will be used up first.
+ */
+size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
+                             unsigned char **pout,
+                             int entropy, size_t min_len, size_t max_len,
+                             int prediction_resistance)
+{
+    size_t ret = 0;
+    size_t entropy_available = 0;
+    RAND_POOL *pool;
+
+    if (drbg->parent != NULL && drbg->strength > drbg->parent->strength) {
+        /*
+         * We currently don't support the algorithm from NIST SP 800-90C
+         * 10.1.2 to use a weaker DRBG as source
+         */
+        RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_R_PARENT_STRENGTH_TOO_WEAK);
+        return 0;
+    }
+
+    if (drbg->seed_pool != NULL) {
+        pool = drbg->seed_pool;
+        pool->entropy_requested = entropy;
+    } else {
+        pool = rand_pool_new(entropy, drbg->secure, min_len, max_len);
+        if (pool == NULL)
+            return 0;
+    }
+
+    if (drbg->parent != NULL) {
+        size_t bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+        unsigned char *buffer = rand_pool_add_begin(pool, bytes_needed);
+
+        if (buffer != NULL) {
+            size_t bytes = 0;
+
+            /*
+             * Get random data from parent. Include our address as additional input,
+             * in order to provide some additional distinction between different
+             * DRBG child instances.
+             * Our lock is already held, but we need to lock our parent before
+             * generating bits from it. (Note: taking the lock will be a no-op
+             * if locking if drbg->parent->lock == NULL.)
+             */
+            rand_drbg_lock(drbg->parent);
+            if (RAND_DRBG_generate(drbg->parent,
+                                   buffer, bytes_needed,
+                                   prediction_resistance,
+                                   (unsigned char *)&drbg, sizeof(drbg)) != 0)
+                bytes = bytes_needed;
+            drbg->reseed_next_counter
+                = tsan_load(&drbg->parent->reseed_prop_counter);
+            rand_drbg_unlock(drbg->parent);
+
+            rand_pool_add_end(pool, bytes, 8 * bytes);
+            entropy_available = rand_pool_entropy_available(pool);
+        }
+
+    } else {
+        /* Get entropy by polling system entropy sources. */
+        entropy_available = rand_pool_acquire_entropy(pool);
+    }
+
+    if (entropy_available > 0) {
+        ret   = rand_pool_length(pool);
+        *pout = rand_pool_detach(pool);
+    }
+
+    if (drbg->seed_pool == NULL)
+        rand_pool_free(pool);
+    return ret;
+}
+
+/*
+ * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ */
+void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
+                               unsigned char *out, size_t outlen)
+{
+    if (drbg->seed_pool == NULL) {
+        if (drbg->secure)
+            OPENSSL_secure_clear_free(out, outlen);
+        else
+            OPENSSL_clear_free(out, outlen);
+    }
+}
+
+/*
+ * Generate additional data that can be used for the drbg. The data does
+ * not need to contain entropy, but it's useful if it contains at least
+ * some bits that are unpredictable.
+ *
+ * Returns 0 on failure.
+ *
+ * On success it allocates a buffer at |*pout| and returns the length of
+ * the data. The buffer should get freed using OPENSSL_secure_clear_free().
+ */
+size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)
+{
+    size_t ret = 0;
+
+    if (rand_pool_add_additional_data(pool) == 0)
+        goto err;
+
+    ret = rand_pool_length(pool);
+    *pout = rand_pool_detach(pool);
+
+ err:
+    return ret;
+}
+
+void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
+{
+    rand_pool_reattach(pool, out);
+}
+#endif
+
+#ifndef FIPS_MODULE
+DEFINE_RUN_ONCE_STATIC(do_rand_init)
+{
+# ifndef OPENSSL_NO_ENGINE
+    rand_engine_lock = CRYPTO_THREAD_lock_new();
+    if (rand_engine_lock == NULL)
+        return 0;
+# endif
+
+    rand_meth_lock = CRYPTO_THREAD_lock_new();
+    if (rand_meth_lock == NULL)
+        goto err;
+
+    if (!rand_pool_init())
+        goto err;
+
+    rand_inited = 1;
+    return 1;
+
+ err:
+    CRYPTO_THREAD_lock_free(rand_meth_lock);
+    rand_meth_lock = NULL;
+# ifndef OPENSSL_NO_ENGINE
+    CRYPTO_THREAD_lock_free(rand_engine_lock);
+    rand_engine_lock = NULL;
+# endif
+    return 0;
+}
+
+void rand_cleanup_int(void)
+{
+    const RAND_METHOD *meth = default_RAND_meth;
+
+    if (!rand_inited)
+        return;
+
+    if (meth != NULL && meth->cleanup != NULL)
+        meth->cleanup();
+    RAND_set_rand_method(NULL);
+    rand_pool_cleanup();
+# ifndef OPENSSL_NO_ENGINE
+    CRYPTO_THREAD_lock_free(rand_engine_lock);
+    rand_engine_lock = NULL;
+# endif
+    CRYPTO_THREAD_lock_free(rand_meth_lock);
+    rand_meth_lock = NULL;
+    rand_inited = 0;
+}
+
+/* TODO(3.0): Do we need to handle this somehow in the FIPS module? */
+/*
+ * RAND_close_seed_files() ensures that any seed file descriptors are
+ * closed after use.
+ */
+void RAND_keep_random_devices_open(int keep)
+{
+    if (RUN_ONCE(&rand_init, do_rand_init))
+        rand_pool_keep_random_devices_open(keep);
+}
+
+/*
+ * RAND_poll() reseeds the default RNG using random input
+ *
+ * The random input is obtained from polling various entropy
+ * sources which depend on the operating system and are
+ * configurable via the --with-rand-seed configure option.
+ */
+int RAND_poll(void)
+{
+    int ret = 0;
+
+    const RAND_METHOD *meth = RAND_get_rand_method();
+
+    if (meth == NULL)
+        return 0;
+
+    if (meth == RAND_OpenSSL()) {
+        /* fill random pool and seed the master DRBG */
+        RAND_DRBG *drbg = RAND_DRBG_get0_master();
+
+        if (drbg == NULL)
+            return 0;
+
+#if 0
+        ret = rand_drbg_restart(drbg, NULL, 0, 0);
 #endif
-static const RAND_METHOD *default_RAND_meth = NULL;
+
+        return ret;
+
+    } else {
+        RAND_POOL *pool = NULL;
+
+        /* fill random pool and seed the current legacy RNG */
+        pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
+                             (RAND_DRBG_STRENGTH + 7) / 8,
+                             RAND_POOL_MAX_LENGTH);
+        if (pool == NULL)
+            return 0;
+#if 0
+        if (rand_pool_acquire_entropy(pool) == 0)
+            goto err;
+#endif
+        if (meth->add == NULL
+            || meth->add(rand_pool_buffer(pool),
+                         rand_pool_length(pool),
+                         (rand_pool_entropy(pool) / 8.0)) == 0)
+            goto err;
+
+        ret = 1;
+
+     err:
+        rand_pool_free(pool);
+    }
+
+    return ret;
+}
 
 int RAND_set_rand_method(const RAND_METHOD *meth)
 {
-#ifndef OPENSSL_NO_ENGINE
+    if (!RUN_ONCE(&rand_init, do_rand_init))
+        return 0;
+
+    CRYPTO_THREAD_write_lock(rand_meth_lock);
+# ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(funct_ref);
     funct_ref = NULL;
-#endif
+# endif
     default_RAND_meth = meth;
+    CRYPTO_THREAD_unlock(rand_meth_lock);
     return 1;
 }
+#endif /* FIPS_MODULE */
 
 const RAND_METHOD *RAND_get_rand_method(void)
 {
-    if (!default_RAND_meth) {
-#ifndef OPENSSL_NO_ENGINE
-        ENGINE *e = ENGINE_get_default_RAND();
-        if (e) {
-            default_RAND_meth = ENGINE_get_RAND(e);
-            if (default_RAND_meth == NULL) {
-                ENGINE_finish(e);
-                e = NULL;
-            }
-        }
-        if (e)
+#ifdef FIPS_MODULE
+    return NULL;
+#else
+    const RAND_METHOD *tmp_meth = NULL;
+
+    if (!RUN_ONCE(&rand_init, do_rand_init))
+        return NULL;
+
+    CRYPTO_THREAD_write_lock(rand_meth_lock);
+    if (default_RAND_meth == NULL) {
+# ifndef OPENSSL_NO_ENGINE
+        ENGINE *e;
+
+        /* If we have an engine that can do RAND, use it. */
+        if ((e = ENGINE_get_default_RAND()) != NULL
+                && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
             funct_ref = e;
-        else
-#endif
-            default_RAND_meth = RAND_OpenSSL();
+            default_RAND_meth = tmp_meth;
+        } else {
+            ENGINE_finish(e);
+            default_RAND_meth = &rand_meth;
+        }
+# else
+        default_RAND_meth = &rand_meth;
+# endif
     }
-    return default_RAND_meth;
+    tmp_meth = default_RAND_meth;
+    CRYPTO_THREAD_unlock(rand_meth_lock);
+    return tmp_meth;
+#endif
 }
 
-#ifndef OPENSSL_NO_ENGINE
+#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE)
 int RAND_set_rand_engine(ENGINE *engine)
 {
     const RAND_METHOD *tmp_meth = NULL;
-    if (engine) {
+
+    if (!RUN_ONCE(&rand_init, do_rand_init))
+        return 0;
+
+    if (engine != NULL) {
         if (!ENGINE_init(engine))
             return 0;
         tmp_meth = ENGINE_get_RAND(engine);
@@ -70,57 +423,101 @@ int RAND_set_rand_engine(ENGINE *engine)
             return 0;
         }
     }
+    CRYPTO_THREAD_write_lock(rand_engine_lock);
     /* This function releases any prior ENGINE so call it first */
     RAND_set_rand_method(tmp_meth);
     funct_ref = engine;
+    CRYPTO_THREAD_unlock(rand_engine_lock);
     return 1;
 }
 #endif
 
-void rand_cleanup_int(void)
+void RAND_seed(const void *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->cleanup)
-        meth->cleanup();
-    RAND_set_rand_method(NULL);
+
+    if (meth != NULL && meth->seed != NULL)
+        meth->seed(buf, num);
 }
 
-void RAND_seed(const void *buf, int num)
+void RAND_add(const void *buf, int num, double randomness)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->seed)
-        meth->seed(buf, num);
+
+    if (meth != NULL && meth->add != NULL)
+        meth->add(buf, num, randomness);
 }
 
-void RAND_add(const void *buf, int num, double entropy)
+/*
+ * This function is not part of RAND_METHOD, so if we're not using
+ * the default method, then just call RAND_bytes().  Otherwise make
+ * sure we're instantiated and use the private DRBG.
+ */
+int RAND_priv_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
 {
+    RAND_DRBG *drbg;
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->add)
-        meth->add(buf, num, entropy);
+
+    if (meth != NULL && meth != RAND_OpenSSL()) {
+        if (meth->bytes != NULL)
+            return meth->bytes(buf, num);
+        RANDerr(RAND_F_RAND_PRIV_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
+        return -1;
+    }
+
+    drbg = OPENSSL_CTX_get0_private_drbg(ctx);
+    if (drbg != NULL)
+        return RAND_DRBG_bytes(drbg, buf, num);
+
+    return 0;
 }
 
-int RAND_bytes(unsigned char *buf, int num)
+int RAND_priv_bytes(unsigned char *buf, int num)
 {
+    return RAND_priv_bytes_ex(NULL, buf, num);
+}
+
+int RAND_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
+{
+    RAND_DRBG *drbg;
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->bytes)
-        return meth->bytes(buf, num);
-    return (-1);
+
+    if (meth != NULL && meth != RAND_OpenSSL()) {
+        if (meth->bytes != NULL)
+            return meth->bytes(buf, num);
+        RANDerr(RAND_F_RAND_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
+        return -1;
+    }
+
+    drbg = OPENSSL_CTX_get0_public_drbg(ctx);
+    if (drbg != NULL)
+        return RAND_DRBG_bytes(drbg, buf, num);
+
+    return 0;
+}
+
+int RAND_bytes(unsigned char *buf, int num)
+{
+    return RAND_bytes_ex(NULL, buf, num);
 }
 
-#if OPENSSL_API_COMPAT < 0x10100000L
+#if !defined(OPENSSL_NO_DEPRECATED_1_1_0) && !defined(FIPS_MODULE)
 int RAND_pseudo_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->pseudorand)
+
+    if (meth != NULL && meth->pseudorand != NULL)
         return meth->pseudorand(buf, num);
-    return (-1);
+    RANDerr(RAND_F_RAND_PSEUDO_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
+    return -1;
 }
 #endif
 
 int RAND_status(void)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->status)
+
+    if (meth != NULL && meth->status != NULL)
         return meth->status();
     return 0;
 }