doc: Documentation changes for moving the entropy source out of the fips provider

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/13226)

1 files changed, 0 insertions, 412 deletions

diff --git a/providers/implementations/rands/rand_pool.c b/providers/implementations/rands/rand_pool.c
deleted file mode 100644
index c66c0e3..0000000
--- a/providers/implementations/rands/rand_pool.c
+++ /dev/null
@@ -1,412 +0,0 @@
-/*
- * Copyright 1995-2020 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 <stdio.h>
-#include <time.h>
-#include "internal/cryptlib.h"
-#include <openssl/opensslconf.h>
-#include "crypto/rand.h"
-#include <openssl/engine.h>
-#include "internal/thread_once.h"
-#include "prov/rand_pool.h"
-
-/*
- * Allocate memory and initialize a new random pool
- */
-RAND_POOL *rand_pool_new(int entropy_requested, int secure,
-                         size_t min_len, size_t max_len)
-{
-    RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
-    size_t min_alloc_size = RAND_POOL_MIN_ALLOCATION(secure);
-
-    if (pool == NULL) {
-        ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
-        return NULL;
-    }
-
-    pool->min_len = min_len;
-    pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
-        RAND_POOL_MAX_LENGTH : max_len;
-    pool->alloc_len = min_len < min_alloc_size ? min_alloc_size : min_len;
-    if (pool->alloc_len > pool->max_len)
-        pool->alloc_len = pool->max_len;
-
-    if (secure)
-        pool->buffer = OPENSSL_secure_zalloc(pool->alloc_len);
-    else
-        pool->buffer = OPENSSL_zalloc(pool->alloc_len);
-
-    if (pool->buffer == NULL) {
-        ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
-        goto err;
-    }
-
-    pool->entropy_requested = entropy_requested;
-    pool->secure = secure;
-    return pool;
-
-err:
-    OPENSSL_free(pool);
-    return NULL;
-}
-
-/*
- * Attach new random pool to the given buffer
- *
- * This function is intended to be used only for feeding random data
- * provided by RAND_add() and RAND_seed() into the <master> DRBG.
- */
-RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
-                            size_t entropy)
-{
-    RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
-
-    if (pool == NULL) {
-        ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
-        return NULL;
-    }
-
-    /*
-     * The const needs to be cast away, but attached buffers will not be
-     * modified (in contrary to allocated buffers which are zeroed and
-     * freed in the end).
-     */
-    pool->buffer = (unsigned char *) buffer;
-    pool->len = len;
-
-    pool->attached = 1;
-
-    pool->min_len = pool->max_len = pool->alloc_len = pool->len;
-    pool->entropy = entropy;
-
-    return pool;
-}
-
-/*
- * Free |pool|, securely erasing its buffer.
- */
-void rand_pool_free(RAND_POOL *pool)
-{
-    if (pool == NULL)
-        return;
-
-    /*
-     * Although it would be advisable from a cryptographical viewpoint,
-     * we are not allowed to clear attached buffers, since they are passed
-     * to rand_pool_attach() as `const unsigned char*`.
-     * (see corresponding comment in rand_pool_attach()).
-     */
-    if (!pool->attached) {
-        if (pool->secure)
-            OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
-        else
-            OPENSSL_clear_free(pool->buffer, pool->alloc_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() or to re-attach it
- * again to the pool using rand_pool_reattach().
- */
-unsigned char *rand_pool_detach(RAND_POOL *pool)
-{
-    unsigned char *ret = pool->buffer;
-    pool->buffer = NULL;
-    pool->entropy = 0;
-    return ret;
-}
-
-/*
- * Re-attach the |pool| buffer. It is only allowed to pass
- * the |buffer| which was previously detached from the same pool.
- */
-void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer)
-{
-    pool->buffer = buffer;
-    OPENSSL_cleanse(pool->buffer, pool->len);
-    pool->len = 0;
-}
-
-/*
- * If |entropy_factor| bits contain 1 bit of entropy, how many bytes does one
- * need to obtain at least |bits| bits of entropy?
- */
-#define ENTROPY_TO_BYTES(bits, entropy_factor) \
-    (((bits) * (entropy_factor) + 7) / 8)
-
-
-/*
- * 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->entropy_requested)
-        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->entropy_requested)
-        return pool->entropy_requested - pool->entropy;
-
-    return 0;
-}
-
-/* Increase the allocation size -- not usable for an attached pool */
-static int rand_pool_grow(RAND_POOL *pool, size_t len)
-{
-    if (len > pool->alloc_len - pool->len) {
-        unsigned char *p;
-        const size_t limit = pool->max_len / 2;
-        size_t newlen = pool->alloc_len;
-
-        if (pool->attached || len > pool->max_len - pool->len) {
-            ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
-            return 0;
-        }
-
-        do
-            newlen = newlen < limit ? newlen * 2 : pool->max_len;
-        while (len > newlen - pool->len);
-
-        if (pool->secure)
-            p = OPENSSL_secure_zalloc(newlen);
-        else
-            p = OPENSSL_zalloc(newlen);
-        if (p == NULL) {
-            ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
-            return 0;
-        }
-        memcpy(p, pool->buffer, pool->len);
-        if (pool->secure)
-            OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
-        else
-            OPENSSL_clear_free(pool->buffer, pool->alloc_len);
-        pool->buffer = p;
-        pool->alloc_len = newlen;
-    }
-    return 1;
-}
-
-/*
- * Returns the number of bytes needed to fill the pool, assuming
- * the input has 1 / |entropy_factor| entropy bits per data bit.
- * In case of an error, 0 is returned.
- */
-
-size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
-{
-    size_t bytes_needed;
-    size_t entropy_needed = rand_pool_entropy_needed(pool);
-
-    if (entropy_factor < 1) {
-        ERR_raise(ERR_LIB_RAND, RAND_R_ARGUMENT_OUT_OF_RANGE);
-        return 0;
-    }
-
-    bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_factor);
-
-    if (bytes_needed > pool->max_len - pool->len) {
-        /* not enough space left */
-        ERR_raise(ERR_LIB_RAND, 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;
-
-    /*
-     * Make sure the buffer is large enough for the requested amount
-     * of data. This guarantees that existing code patterns where
-     * rand_pool_add_begin, rand_pool_add_end or rand_pool_add
-     * are used to collect entropy data without any error handling
-     * whatsoever, continue to be valid.
-     * Furthermore if the allocation here fails once, make sure that
-     * we don't fall back to a less secure or even blocking random source,
-     * as that could happen by the existing code patterns.
-     * This is not a concern for additional data, therefore that
-     * is not needed if rand_pool_grow fails in other places.
-     */
-    if (!rand_pool_grow(pool, bytes_needed)) {
-        /* persistent error for this pool */
-        pool->max_len = pool->len = 0;
-        return 0;
-    }
-
-    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.
- *
- * Returns 1 if the added amount is adequate, otherwise 0
- */
-int rand_pool_add(RAND_POOL *pool,
-                  const unsigned char *buffer, size_t len, size_t entropy)
-{
-    if (len > pool->max_len - pool->len) {
-        ERR_raise(ERR_LIB_RAND, RAND_R_ENTROPY_INPUT_TOO_LONG);
-        return 0;
-    }
-
-    if (pool->buffer == NULL) {
-        ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
-        return 0;
-    }
-
-    if (len > 0) {
-        /*
-         * This is to protect us from accidentally passing the buffer
-         * returned from rand_pool_add_begin.
-         * The check for alloc_len makes sure we do not compare the
-         * address of the end of the allocated memory to something
-         * different, since that comparison would have an
-         * indeterminate result.
-         */
-        if (pool->alloc_len > pool->len && pool->buffer + pool->len == buffer) {
-            ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
-            return 0;
-        }
-        /*
-         * We have that only for cases when a pool is used to collect
-         * additional data.
-         * For entropy data, as long as the allocation request stays within
-         * the limits given by rand_pool_bytes_needed this rand_pool_grow
-         * below is guaranteed to succeed, thus no allocation happens.
-         */
-        if (!rand_pool_grow(pool, len))
-            return 0;
-        memcpy(pool->buffer + pool->len, buffer, len);
-        pool->len += len;
-        pool->entropy += entropy;
-    }
-
-    return 1;
-}
-
-/*
- * 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 update 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) {
-        ERR_raise(ERR_LIB_RAND, RAND_R_RANDOM_POOL_OVERFLOW);
-        return NULL;
-    }
-
-    if (pool->buffer == NULL) {
-        ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
-        return NULL;
-    }
-
-    /*
-     * As long as the allocation request stays within the limits given
-     * by rand_pool_bytes_needed this rand_pool_grow below is guaranteed
-     * to succeed, thus no allocation happens.
-     * We have that only for cases when a pool is used to collect
-     * additional data. Then the buffer might need to grow here,
-     * and of course the caller is responsible to check the return
-     * value of this function.
-     */
-    if (!rand_pool_grow(pool, len))
-        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.
- */
-int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy)
-{
-    if (len > pool->alloc_len - pool->len) {
-        ERR_raise(ERR_LIB_RAND, RAND_R_RANDOM_POOL_OVERFLOW);
-        return 0;
-    }
-
-    if (len > 0) {
-        pool->len += len;
-        pool->entropy += entropy;
-    }
-
-    return 1;
-}