/src/openssl30/crypto/rand/rand_pool.c

Source
/*
 * Copyright 1995-2021 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 "crypto/rand_pool.h"

/*
 * Allocate memory and initialize a new random pool
 */
RAND_POOL *ossl_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 *ossl_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 ossl_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 ossl_rand_pool_attach() as `const unsigned char*`.
     * (see corresponding comment in ossl_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 *ossl_rand_pool_buffer(RAND_POOL *pool)
{
    return pool->buffer;
}

/*
 * Return the |pool|'s entropy to the caller.
 */
size_t ossl_rand_pool_entropy(RAND_POOL *pool)
{
    return pool->entropy;
}

/*
 * Return the |pool|'s buffer length to the caller.
 */
size_t ossl_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 ossl_rand_pool_reattach().
 */
unsigned char *ossl_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 ossl_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 ossl_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 ossl_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 ossl_rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
{
    size_t bytes_needed;
    size_t entropy_needed = ossl_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
     * ossl_rand_pool_add_begin, ossl_rand_pool_add_end or ossl_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 ossl_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 ossl_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 ossl_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 ossl_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, ossl_rand_pool_add_end() needs to be called
 * to finish the update operation (see next comment).
 */
unsigned char *ossl_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 ossl_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
 * ossl_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 ossl_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;
}

Coverage Report

Created: 2025-12-31 06:58

Line	Count	Source
1		/*
2		* Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the Apache License 2.0 (the "License"). You may not use
5		* this file except in compliance with the License. You can obtain a copy
6		* in the file LICENSE in the source distribution or at
7		* https://www.openssl.org/source/license.html
8		*/
9
10		#include <stdio.h>
11		#include <time.h>
12		#include "internal/cryptlib.h"
13		#include <openssl/opensslconf.h>
14		#include "crypto/rand.h"
15		#include <openssl/engine.h>
16		#include "internal/thread_once.h"
17		#include "crypto/rand_pool.h"
18
19		/*
20		* Allocate memory and initialize a new random pool
21		*/
22		RAND_POOL *ossl_rand_pool_new(int entropy_requested, int secure,
23		size_t min_len, size_t max_len)
24	1.49k	{
25	1.49k	RAND_POOL pool = OPENSSL_zalloc(sizeof(pool));
26	1.49k	size_t min_alloc_size = RAND_POOL_MIN_ALLOCATION(secure);
27
28	1.49k	if (pool == NULL) {
29	0	ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
30	0	return NULL;
31	0	}
32
33	1.49k	pool->min_len = min_len;
34	1.49k	pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ? RAND_POOL_MAX_LENGTH : max_len;
35	1.49k	pool->alloc_len = min_len < min_alloc_size ? min_alloc_size : min_len;
36	1.49k	if (pool->alloc_len > pool->max_len)
37	25	pool->alloc_len = pool->max_len;
38
39	1.49k	if (secure)
40	1.07k	pool->buffer = OPENSSL_secure_zalloc(pool->alloc_len);
41	413	else
42	413	pool->buffer = OPENSSL_zalloc(pool->alloc_len);
43
44	1.49k	if (pool->buffer == NULL) {
45	0	ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
46	0	goto err;
47	0	}
48
49	1.49k	pool->entropy_requested = entropy_requested;
50	1.49k	pool->secure = secure;
51	1.49k	return pool;
52
53	0	err:
54	0	OPENSSL_free(pool);
55	0	return NULL;
56	1.49k	}
57
58		/*
59		* Attach new random pool to the given buffer
60		*
61		* This function is intended to be used only for feeding random data
62		* provided by RAND_add() and RAND_seed() into the <master> DRBG.
63		*/
64		RAND_POOL ossl_rand_pool_attach(const unsigned char buffer, size_t len,
65		size_t entropy)
66	0	{
67	0	RAND_POOL pool = OPENSSL_zalloc(sizeof(pool));
68
69	0	if (pool == NULL) {
70	0	ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
71	0	return NULL;
72	0	}
73
74		/*
75		* The const needs to be cast away, but attached buffers will not be
76		* modified (in contrary to allocated buffers which are zeroed and
77		* freed in the end).
78		*/
79	0	pool->buffer = (unsigned char *)buffer;
80	0	pool->len = len;
81
82	0	pool->attached = 1;
83
84	0	pool->min_len = pool->max_len = pool->alloc_len = pool->len;
85	0	pool->entropy = entropy;
86
87	0	return pool;
88	0	}
89
90		/*
91		* Free \|pool\|, securely erasing its buffer.
92		*/
93		void ossl_rand_pool_free(RAND_POOL *pool)
94	1.49k	{
95	1.49k	if (pool == NULL)
96	0	return;
97
98		/*
99		* Although it would be advisable from a cryptographical viewpoint,
100		* we are not allowed to clear attached buffers, since they are passed
101		* to ossl_rand_pool_attach() as `const unsigned char*`.
102		* (see corresponding comment in ossl_rand_pool_attach()).
103		*/
104	1.49k	if (!pool->attached) {
105	1.49k	if (pool->secure)
106	1.07k	OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
107	413	else
108	413	OPENSSL_clear_free(pool->buffer, pool->alloc_len);
109	1.49k	}
110
111	1.49k	OPENSSL_free(pool);
112	1.49k	}
113
114		/*
115		* Return the \|pool\|'s buffer to the caller (readonly).
116		*/
117		const unsigned char ossl_rand_pool_buffer(RAND_POOL pool)
118	65	{
119	65	return pool->buffer;
120	65	}
121
122		/*
123		* Return the \|pool\|'s entropy to the caller.
124		*/
125		size_t ossl_rand_pool_entropy(RAND_POOL *pool)
126	0	{
127	0	return pool->entropy;
128	0	}
129
130		/*
131		* Return the \|pool\|'s buffer length to the caller.
132		*/
133		size_t ossl_rand_pool_length(RAND_POOL *pool)
134	1.48k	{
135	1.48k	return pool->len;
136	1.48k	}
137
138		/*
139		* Detach the \|pool\| buffer and return it to the caller.
140		* It's the responsibility of the caller to free the buffer
141		* using OPENSSL_secure_clear_free() or to re-attach it
142		* again to the pool using ossl_rand_pool_reattach().
143		*/
144		unsigned char ossl_rand_pool_detach(RAND_POOL pool)
145	1.42k	{
146	1.42k	unsigned char *ret = pool->buffer;
147	1.42k	pool->buffer = NULL;
148	1.42k	pool->entropy = 0;
149	1.42k	return ret;
150	1.42k	}
151
152		/*
153		* Re-attach the \|pool\| buffer. It is only allowed to pass
154		* the \|buffer\| which was previously detached from the same pool.
155		*/
156		void ossl_rand_pool_reattach(RAND_POOL pool, unsigned char buffer)
157	0	{
158	0	pool->buffer = buffer;
159	0	OPENSSL_cleanse(pool->buffer, pool->len);
160	0	pool->len = 0;
161	0	}
162
163		/*
164		* If \|entropy_factor\| bits contain 1 bit of entropy, how many bytes does one
165		* need to obtain at least \|bits\| bits of entropy?
166		*/
167		#define ENTROPY_TO_BYTES(bits, entropy_factor) \
168	1.07k	(((bits) * (entropy_factor) + 7) / 8)
169
170		/*
171		* Checks whether the \|pool\|'s entropy is available to the caller.
172		* This is the case when entropy count and buffer length are high enough.
173		* Returns
174		*
175		* \|entropy\| if the entropy count and buffer size is large enough
176		* 0 otherwise
177		*/
178		size_t ossl_rand_pool_entropy_available(RAND_POOL *pool)
179	1.07k	{
180	1.07k	if (pool->entropy < pool->entropy_requested)
181	0	return 0;
182
183	1.07k	if (pool->len < pool->min_len)
184	0	return 0;
185
186	1.07k	return pool->entropy;
187	1.07k	}
188
189		/*
190		* Returns the (remaining) amount of entropy needed to fill
191		* the random pool.
192		*/
193
194		size_t ossl_rand_pool_entropy_needed(RAND_POOL *pool)
195	1.07k	{
196	1.07k	if (pool->entropy < pool->entropy_requested)
197	1.01k	return pool->entropy_requested - pool->entropy;
198
199	66	return 0;
200	1.07k	}
201
202		/* Increase the allocation size -- not usable for an attached pool */
203		static int rand_pool_grow(RAND_POOL *pool, size_t len)
204	2.97k	{
205	2.97k	if (len > pool->alloc_len - pool->len) {
206	0	unsigned char *p;
207	0	const size_t limit = pool->max_len / 2;
208	0	size_t newlen = pool->alloc_len;
209
210	0	if (pool->attached \|\| len > pool->max_len - pool->len) {
211	0	ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
212	0	return 0;
213	0	}
214
215	0	do
216	0	newlen = newlen < limit ? newlen * 2 : pool->max_len;
217	0	while (len > newlen - pool->len);
218
219	0	if (pool->secure)
220	0	p = OPENSSL_secure_zalloc(newlen);
221	0	else
222	0	p = OPENSSL_zalloc(newlen);
223	0	if (p == NULL) {
224	0	ERR_raise(ERR_LIB_RAND, ERR_R_MALLOC_FAILURE);
225	0	return 0;
226	0	}
227	0	memcpy(p, pool->buffer, pool->len);
228	0	if (pool->secure)
229	0	OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
230	0	else
231	0	OPENSSL_clear_free(pool->buffer, pool->alloc_len);
232	0	pool->buffer = p;
233	0	pool->alloc_len = newlen;
234	0	}
235	2.97k	return 1;
236	2.97k	}
237
238		/*
239		* Returns the number of bytes needed to fill the pool, assuming
240		* the input has 1 / \|entropy_factor\| entropy bits per data bit.
241		* In case of an error, 0 is returned.
242		*/
243
244		size_t ossl_rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
245	1.07k	{
246	1.07k	size_t bytes_needed;
247	1.07k	size_t entropy_needed = ossl_rand_pool_entropy_needed(pool);
248
249	1.07k	if (entropy_factor < 1) {
250	0	ERR_raise(ERR_LIB_RAND, RAND_R_ARGUMENT_OUT_OF_RANGE);
251	0	return 0;
252	0	}
253
254	1.07k	bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_factor);
255
256	1.07k	if (bytes_needed > pool->max_len - pool->len) {
257		/* not enough space left */
258	0	ERR_raise(ERR_LIB_RAND, RAND_R_RANDOM_POOL_OVERFLOW);
259	0	return 0;
260	0	}
261
262	1.07k	if (pool->len < pool->min_len && bytes_needed < pool->min_len - pool->len)
263		/* to meet the min_len requirement */
264	68	bytes_needed = pool->min_len - pool->len;
265
266		/*
267		* Make sure the buffer is large enough for the requested amount
268		* of data. This guarantees that existing code patterns where
269		* ossl_rand_pool_add_begin, ossl_rand_pool_add_end or ossl_rand_pool_add
270		* are used to collect entropy data without any error handling
271		* whatsoever, continue to be valid.
272		* Furthermore if the allocation here fails once, make sure that
273		* we don't fall back to a less secure or even blocking random source,
274		* as that could happen by the existing code patterns.
275		* This is not a concern for additional data, therefore that
276		* is not needed if rand_pool_grow fails in other places.
277		*/
278	1.07k	if (!rand_pool_grow(pool, bytes_needed)) {
279		/* persistent error for this pool */
280	0	pool->max_len = pool->len = 0;
281	0	return 0;
282	0	}
283
284	1.07k	return bytes_needed;
285	1.07k	}
286
287		/* Returns the remaining number of bytes available */
288		size_t ossl_rand_pool_bytes_remaining(RAND_POOL *pool)
289	0	{
290	0	return pool->max_len - pool->len;
291	0	}
292
293		/*
294		* Add random bytes to the random pool.
295		*
296		* It is expected that the \|buffer\| contains \|len\| bytes of
297		* random input which contains at least \|entropy\| bits of
298		* randomness.
299		*
300		* Returns 1 if the added amount is adequate, otherwise 0
301		*/
302		int ossl_rand_pool_add(RAND_POOL *pool,
303		const unsigned char *buffer, size_t len, size_t entropy)
304	826	{
305	826	if (len > pool->max_len - pool->len) {
306	0	ERR_raise(ERR_LIB_RAND, RAND_R_ENTROPY_INPUT_TOO_LONG);
307	0	return 0;
308	0	}
309
310	826	if (pool->buffer == NULL) {
311	0	ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
312	0	return 0;
313	0	}
314
315	826	if (len > 0) {
316		/*
317		* This is to protect us from accidentally passing the buffer
318		* returned from ossl_rand_pool_add_begin.
319		* The check for alloc_len makes sure we do not compare the
320		* address of the end of the allocated memory to something
321		* different, since that comparison would have an
322		* indeterminate result.
323		*/
324	826	if (pool->alloc_len > pool->len && pool->buffer + pool->len == buffer) {
325	0	ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
326	0	return 0;
327	0	}
328		/*
329		* We have that only for cases when a pool is used to collect
330		* additional data.
331		* For entropy data, as long as the allocation request stays within
332		* the limits given by ossl_rand_pool_bytes_needed this rand_pool_grow
333		* below is guaranteed to succeed, thus no allocation happens.
334		*/
335	826	if (!rand_pool_grow(pool, len))
336	0	return 0;
337	826	memcpy(pool->buffer + pool->len, buffer, len);
338	826	pool->len += len;
339	826	pool->entropy += entropy;
340	826	}
341
342	826	return 1;
343	826	}
344
345		/*
346		* Start to add random bytes to the random pool in-place.
347		*
348		* Reserves the next \|len\| bytes for adding random bytes in-place
349		* and returns a pointer to the buffer.
350		* The caller is allowed to copy up to \|len\| bytes into the buffer.
351		* If \|len\| == 0 this is considered a no-op and a NULL pointer
352		* is returned without producing an error message.
353		*
354		* After updating the buffer, ossl_rand_pool_add_end() needs to be called
355		* to finish the update operation (see next comment).
356		*/
357		unsigned char ossl_rand_pool_add_begin(RAND_POOL pool, size_t len)
358	1.07k	{
359	1.07k	if (len == 0)
360	0	return NULL;
361
362	1.07k	if (len > pool->max_len - pool->len) {
363	0	ERR_raise(ERR_LIB_RAND, RAND_R_RANDOM_POOL_OVERFLOW);
364	0	return NULL;
365	0	}
366
367	1.07k	if (pool->buffer == NULL) {
368	0	ERR_raise(ERR_LIB_RAND, ERR_R_INTERNAL_ERROR);
369	0	return NULL;
370	0	}
371
372		/*
373		* As long as the allocation request stays within the limits given
374		* by ossl_rand_pool_bytes_needed this rand_pool_grow below is guaranteed
375		* to succeed, thus no allocation happens.
376		* We have that only for cases when a pool is used to collect
377		* additional data. Then the buffer might need to grow here,
378		* and of course the caller is responsible to check the return
379		* value of this function.
380		*/
381	1.07k	if (!rand_pool_grow(pool, len))
382	0	return NULL;
383
384	1.07k	return pool->buffer + pool->len;
385	1.07k	}
386
387		/*
388		* Finish to add random bytes to the random pool in-place.
389		*
390		* Finishes an in-place update of the random pool started by
391		* ossl_rand_pool_add_begin() (see previous comment).
392		* It is expected that \|len\| bytes of random input have been added
393		* to the buffer which contain at least \|entropy\| bits of randomness.
394		* It is allowed to add less bytes than originally reserved.
395		*/
396		int ossl_rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy)
397	1.07k	{
398	1.07k	if (len > pool->alloc_len - pool->len) {
399	0	ERR_raise(ERR_LIB_RAND, RAND_R_RANDOM_POOL_OVERFLOW);
400	0	return 0;
401	0	}
402
403	1.07k	if (len > 0) {
404	1.07k	pool->len += len;
405	1.07k	pool->entropy += entropy;
406	1.07k	}
407
408	1.07k	return 1;
409	1.07k	}