X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frand%2Frand_lib.c;h=6f8deca1f9ff16e3aa72df7c14af90ad14ec339c;hp=fc47dc97a2a4c59c5fd0e69d5848b67a8f96392f;hb=c16de9d8329d41a2433d0f273c080d9d06ad7a87;hpb=b53338cbf8822dd774f9e4057307f347d2b63ff0

diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index fc47dc97a2..6f8deca1f9 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -11,52 +11,579 @@
 #include <time.h>
 #include "internal/cryptlib.h"
 #include <openssl/opensslconf.h>
-#include "internal/rand.h"
-
+#include "internal/rand_int.h"
 #include <openssl/engine.h>
+#include "internal/thread_once.h"
+#include "rand_lcl.h"
 
 #ifndef OPENSSL_NO_ENGINE
 /* non-NULL if default_RAND_meth is ENGINE-provided */
-static ENGINE *funct_ref = NULL;
+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;
+
+int rand_fork_count;
+
+#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
+
+#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);
+
+extern unsigned int OPENSSL_ia32cap_P[];
+
+/*
+ * 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, 8 /*entropy_per_byte*/);
+    if (bytes_needed > 0) {
+        buffer = RAND_POOL_add_begin(pool, bytes_needed);
+
+        if (buffer != NULL) {
+
+            /* If RDSEED is available, use that. */
+            if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
+                if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
+                    == bytes_needed)
+                    return RAND_POOL_add_end(pool,
+                                             bytes_needed,
+                                             8 * bytes_needed);
+            }
+
+            /* Second choice is RDRAND. */
+            if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
+                if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
+                    == bytes_needed)
+                    return RAND_POOL_add_end(pool,
+                                             bytes_needed,
+                                             8 * bytes_needed);
+            }
+
+            return RAND_POOL_add_end(pool, 0, 0);
+        }
+    }
+
+    return RAND_POOL_entropy_available(pool);
+}
 #endif
-static const RAND_METHOD *default_RAND_meth = NULL;
+
+
+/*
+ * 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)
+{
+    size_t ret = 0;
+    size_t entropy_available = 0;
+    RAND_POOL *pool = RAND_POOL_new(entropy, min_len, max_len);
+
+    if (pool == NULL)
+        return 0;
+
+    if (drbg->pool) {
+        RAND_POOL_add(pool,
+                      RAND_POOL_buffer(drbg->pool),
+                      RAND_POOL_length(drbg->pool),
+                      RAND_POOL_entropy(drbg->pool));
+        RAND_POOL_free(drbg->pool);
+        drbg->pool = NULL;
+    }
+
+    if (drbg->parent) {
+        size_t bytes_needed = RAND_POOL_bytes_needed(pool, 8);
+        unsigned char *buffer = RAND_POOL_add_begin(pool, bytes_needed);
+
+        if (buffer != NULL) {
+            size_t bytes = 0;
+
+            /* Get entropy from parent, include our state as additional input */
+            if (RAND_DRBG_generate(drbg->parent,
+                                   buffer, bytes_needed,
+                                   0,
+                                   (unsigned char *)drbg, sizeof(*drbg)) != 0)
+                bytes = bytes_needed;
+
+            entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes);
+        }
+
+    } 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);
+    }
+
+    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)
+{
+    OPENSSL_secure_clear_free(out, outlen);
+}
+
+void rand_fork()
+{
+    rand_fork_count++;
+}
+
+DEFINE_RUN_ONCE_STATIC(do_rand_init)
+{
+    int ret = 1;
+
+#ifndef OPENSSL_NO_ENGINE
+    rand_engine_lock = CRYPTO_THREAD_glock_new("rand_engine");
+    ret &= rand_engine_lock != NULL;
+#endif
+    rand_meth_lock = CRYPTO_THREAD_glock_new("rand_meth");
+    ret &= rand_meth_lock != NULL;
+
+    return ret;
+}
+
+void rand_cleanup_int(void)
+{
+    const RAND_METHOD *meth = default_RAND_meth;
+
+    if (meth != NULL && meth->cleanup != NULL)
+        meth->cleanup();
+    RAND_set_rand_method(NULL);
+#ifndef OPENSSL_NO_ENGINE
+    CRYPTO_THREAD_lock_free(rand_engine_lock);
+#endif
+    CRYPTO_THREAD_lock_free(rand_meth_lock);
+}
+
+/*
+ * 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;
+
+    RAND_POOL *pool = NULL;
+
+    const RAND_METHOD *meth = RAND_get_rand_method();
+
+    if (meth == RAND_OpenSSL()) {
+        /* fill random pool and seed the default DRBG */
+        RAND_DRBG *drbg = RAND_DRBG_get0_global();
+
+        if (drbg == NULL)
+            return 0;
+
+        CRYPTO_THREAD_write_lock(drbg->lock);
+        ret = rand_drbg_restart(drbg, NULL, 0, 0);
+        CRYPTO_THREAD_unlock(drbg->lock);
+
+        return ret;
+
+    } else {
+        /* fill random pool and seed the current legacy RNG */
+        pool = RAND_POOL_new(RAND_DRBG_STRENGTH,
+                             RAND_DRBG_STRENGTH / 8,
+                             DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8));
+        if (pool == NULL)
+            return 0;
+
+        if (RAND_POOL_acquire_entropy(pool) == 0)
+            goto err;
+
+        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;
+}
+
+/*
+ * The 'random pool' acts as a dumb container for collecting random
+ * input from various entropy sources. The pool has no knowledge about
+ * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
+ * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
+ * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
+ * 4) cleanup the random pool again.
+ *
+ * The random pool contains no locking mechanism because its scope and
+ * lifetime is intended to be restricted to a single stack frame.
+ */
+struct rand_pool_st {
+    unsigned char *buffer;  /* points to the beginning of the random pool */
+    size_t len; /* current number of random bytes contained in the pool */
+
+    size_t min_len; /* minimum number of random bytes requested */
+    size_t max_len; /* maximum number of random bytes (allocated buffer size) */
+    size_t entropy; /* current entropy count in bits */
+    size_t requested_entropy; /* requested entropy count in bits */
+};
+
+/*
+ * Allocate memory and initialize a new random pool
+ */
+
+RAND_POOL *RAND_POOL_new(int entropy, size_t min_len, size_t max_len)
+{
+    RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
+
+    if (pool == NULL) {
+        RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    pool->min_len = min_len;
+    pool->max_len = max_len;
+
+    pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
+    if (pool->buffer == NULL) {
+        RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    pool->requested_entropy = entropy;
+
+    return pool;
+
+err:
+    OPENSSL_free(pool);
+    return NULL;
+}
+
+/*
+ * Free |pool|, securely erasing its buffer.
+ */
+void RAND_POOL_free(RAND_POOL *pool)
+{
+    if (pool == NULL)
+        return;
+
+    OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+    OPENSSL_free(pool);
+}
+
+/*
+ * Return the |pool|'s buffer to the caller (readonly).
+ */
+const unsigned char *RAND_POOL_buffer(RAND_POOL *pool)
+{
+    return pool->buffer;
+}
+
+/*
+ * Return the |pool|'s entropy to the caller.
+ */
+size_t RAND_POOL_entropy(RAND_POOL *pool)
+{
+    return pool->entropy;
+}
+
+/*
+ * Return the |pool|'s buffer length to the caller.
+ */
+size_t RAND_POOL_length(RAND_POOL *pool)
+{
+    return pool->len;
+}
+
+/*
+ * Detach the |pool| buffer and return it to the caller.
+ * It's the responsibility of the caller to free the buffer
+ * using OPENSSL_secure_clear_free().
+ */
+unsigned char *RAND_POOL_detach(RAND_POOL *pool)
+{
+    unsigned char *ret = pool->buffer;
+    pool->buffer = NULL;
+    return ret;
+}
+
+
+/*
+ * If every byte of the input contains |entropy_per_bytes| bits of entropy,
+ * how many bytes does one need to obtain at least |bits| bits of entropy?
+ */
+#define ENTROPY_TO_BYTES(bits, entropy_per_bytes) \
+    (((bits) + ((entropy_per_bytes) - 1))/(entropy_per_bytes))
+
+
+/*
+ * Checks whether the |pool|'s entropy is available to the caller.
+ * This is the case when entropy count and buffer length are high enough.
+ * Returns
+ *
+ *  |entropy|  if the entropy count and buffer size is large enough
+ *      0      otherwise
+ */
+size_t RAND_POOL_entropy_available(RAND_POOL *pool)
+{
+    if (pool->entropy < pool->requested_entropy)
+        return 0;
+
+    if (pool->len < pool->min_len)
+        return 0;
+
+    return pool->entropy;
+}
+
+/*
+ * Returns the (remaining) amount of entropy needed to fill
+ * the random pool.
+ */
+
+size_t RAND_POOL_entropy_needed(RAND_POOL *pool)
+{
+    if (pool->entropy < pool->requested_entropy)
+        return pool->requested_entropy - pool->entropy;
+
+    return 0;
+}
+
+/*
+ * Returns the number of bytes needed to fill the pool, assuming
+ * the input has 'entropy_per_byte' entropy bits per byte.
+ * In case of an error, 0 is returned.
+ */
+
+size_t RAND_POOL_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte)
+{
+    size_t bytes_needed;
+    size_t entropy_needed = RAND_POOL_entropy_needed(pool);
+
+    if (entropy_per_byte < 1 || entropy_per_byte > 8) {
+        RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
+        return 0;
+    }
+
+    bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_per_byte);
+
+    if (bytes_needed > pool->max_len - pool->len) {
+        /* not enough space left */
+        RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW);
+        return 0;
+    }
+
+    if (pool->len < pool->min_len &&
+        bytes_needed < pool->min_len - pool->len)
+        /* to meet the min_len requirement */
+        bytes_needed = pool->min_len - pool->len;
+
+    return bytes_needed;
+}
+
+/* Returns the remaining number of bytes available */
+size_t RAND_POOL_bytes_remaining(RAND_POOL *pool)
+{
+    return pool->max_len - pool->len;
+}
+
+/*
+ * Add random bytes to the random pool.
+ *
+ * It is expected that the |buffer| contains |len| bytes of
+ * random input which contains at least |entropy| bits of
+ * randomness.
+ *
+ * Return available amount of entropy after this operation.
+ * (see RAND_POOL_entropy_available(pool))
+ */
+size_t RAND_POOL_add(RAND_POOL *pool,
+                     const unsigned char *buffer, size_t len, size_t entropy)
+{
+    if (len > pool->max_len - pool->len) {
+        RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
+        return 0;
+    }
+
+    if (len > 0) {
+        memcpy(pool->buffer + pool->len, buffer, len);
+        pool->len += len;
+        pool->entropy += entropy;
+    }
+
+    return RAND_POOL_entropy_available(pool);
+}
+
+/*
+ * Start to add random bytes to the random pool in-place.
+ *
+ * Reserves the next |len| bytes for adding random bytes in-place
+ * and returns a pointer to the buffer.
+ * The caller is allowed to copy up to |len| bytes into the buffer.
+ * If |len| == 0 this is considered a no-op and a NULL pointer
+ * is returned without producing an error message.
+ *
+ * After updating the buffer, RAND_POOL_add_end() needs to be called
+ * to finish the udpate operation (see next comment).
+ */
+unsigned char *RAND_POOL_add_begin(RAND_POOL *pool, size_t len)
+{
+    if (len == 0)
+        return NULL;
+
+    if (len > pool->max_len - pool->len) {
+        RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
+        return NULL;
+    }
+
+    return pool->buffer + pool->len;
+}
+
+/*
+ * Finish to add random bytes to the random pool in-place.
+ *
+ * Finishes an in-place update of the random pool started by
+ * RAND_POOL_add_begin() (see previous comment).
+ * It is expected that |len| bytes of random input have been added
+ * to the buffer which contain at least |entropy| bits of randomness.
+ * It is allowed to add less bytes than originally reserved.
+ */
+size_t RAND_POOL_add_end(RAND_POOL *pool, size_t len, size_t entropy)
+{
+    if (len > pool->max_len - pool->len) {
+        RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
+        return 0;
+    }
+
+    if (len > 0) {
+        pool->len += len;
+        pool->entropy += entropy;
+    }
+
+    return RAND_POOL_entropy_available(pool);
+}
 
 int RAND_set_rand_method(const RAND_METHOD *meth)
 {
+    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
     default_RAND_meth = meth;
+    CRYPTO_THREAD_unlock(rand_meth_lock);
     return 1;
 }
 
 const RAND_METHOD *RAND_get_rand_method(void)
 {
-    if (!default_RAND_meth) {
+    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 = 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)
+        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
+            default_RAND_meth = tmp_meth;
+        } else {
+            ENGINE_finish(e);
+            default_RAND_meth = &rand_meth;
+        }
+#else
+        default_RAND_meth = &rand_meth;
 #endif
-            default_RAND_meth = RAND_OpenSSL();
     }
-    return default_RAND_meth;
+    tmp_meth = default_RAND_meth;
+    CRYPTO_THREAD_unlock(rand_meth_lock);
+    return tmp_meth;
 }
 
 #ifndef OPENSSL_NO_ENGINE
 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);
@@ -65,57 +592,77 @@ 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->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->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(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->add)
-        meth->add(buf, num, entropy);
+    RAND_DRBG *drbg;
+
+    if (meth != RAND_OpenSSL())
+        return RAND_bytes(buf, num);
+
+    drbg = RAND_DRBG_get0_priv_global();
+    if (drbg == NULL)
+        return 0;
+
+    return RAND_DRBG_generate(drbg, buf, num, 0, NULL, 0);
 }
 
 int RAND_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->bytes)
+
+    if (meth->bytes != NULL)
         return meth->bytes(buf, num);
-    return (-1);
+    RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
+    return -1;
 }
 
 #if OPENSSL_API_COMPAT < 0x10100000L
 int RAND_pseudo_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->pseudorand)
+
+    if (meth->pseudorand != NULL)
         return meth->pseudorand(buf, num);
-    return (-1);
+    return -1;
 }
 #endif
 
 int RAND_status(void)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();
-    if (meth && meth->status)
+
+    if (meth->status != NULL)
         return meth->status();
     return 0;
 }