share rand_pool between libcrypto and providers

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/11682)
This commit is contained in:
Pauli 2020-05-12 12:20:28 +10:00
parent e1c5b1f6b4
commit bcdea3badf
10 changed files with 523 additions and 109 deletions

View File

@ -20,9 +20,6 @@
# include <openssl/rand.h>
/* forward declaration */
typedef struct rand_pool_st RAND_POOL;
/*
* Defines related to seed sources
*/
@ -74,101 +71,6 @@ typedef struct rand_pool_st RAND_POOL;
void rand_cleanup_int(void);
/* Hardware-based seeding functions. */
size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
/* DRBG entropy callbacks. */
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);
void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen);
size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
unsigned char **pout,
int entropy, size_t min_len, size_t max_len);
void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
unsigned char *out, size_t outlen);
size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout);
void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out);
/* CRNG test entropy filter callbacks. */
size_t rand_crngt_get_entropy(RAND_DRBG *drbg,
unsigned char **pout,
int entropy, size_t min_len, size_t max_len,
int prediction_resistance);
void rand_crngt_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen);
/*
* RAND_POOL functions
*/
RAND_POOL *rand_pool_new(int entropy_requested, int secure,
size_t min_len, size_t max_len);
RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
size_t entropy);
void rand_pool_free(RAND_POOL *pool);
const unsigned char *rand_pool_buffer(RAND_POOL *pool);
unsigned char *rand_pool_detach(RAND_POOL *pool);
void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer);
size_t rand_pool_entropy(RAND_POOL *pool);
size_t rand_pool_length(RAND_POOL *pool);
size_t rand_pool_entropy_available(RAND_POOL *pool);
size_t rand_pool_entropy_needed(RAND_POOL *pool);
/* |entropy_factor| expresses how many bits of data contain 1 bit of entropy */
size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor);
size_t rand_pool_bytes_remaining(RAND_POOL *pool);
int rand_pool_add(RAND_POOL *pool,
const unsigned char *buffer, size_t len, size_t entropy);
unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len);
int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy);
/*
* Add random bytes to the pool to acquire requested amount of entropy
*
* This function is platform specific and tries to acquire the requested
* amount of entropy by polling platform specific entropy sources.
*
* If the function succeeds in acquiring at least |entropy_requested| bits
* of entropy, the total entropy count is returned. If it fails, it returns
* an entropy count of 0.
*/
size_t rand_pool_acquire_entropy(RAND_POOL *pool);
/*
* Add some application specific nonce data
*
* This function is platform specific and adds some application specific
* data to the nonce used for instantiating the drbg.
*
* This data currently consists of the process and thread id, and a high
* resolution timestamp. The data does not include an atomic counter,
* because that is added by the calling function rand_drbg_get_nonce().
*
* Returns 1 on success and 0 on failure.
*/
int rand_pool_add_nonce_data(RAND_POOL *pool);
/*
* Add some platform specific additional data
*
* This function is platform specific and adds some random noise to the
* additional data used for generating random bytes and for reseeding
* the drbg.
*
* Returns 1 on success and 0 on failure.
*/
int rand_pool_add_additional_data(RAND_POOL *pool);
/*
* Initialise the random pool reseeding sources.
*

View File

@ -0,0 +1,108 @@
/*
* 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
*/
#ifndef OSSL_PROVIDER_RAND_POOL_H
# define OSSL_PROVIDER_RAND_POOL_H
# include <stdio.h>
# include <openssl/rand_drbg.h>
/*
* Maximum allocation size for RANDOM_POOL buffers
*
* The max_len value for the buffer provided to the rand_drbg_get_entropy()
* callback is currently 2^31 bytes (2 gigabytes), if a derivation function
* is used. Since this is much too large to be allocated, the rand_pool_new()
* function chooses more modest values as default pool length, bounded
* by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH
*
* The choice of the RAND_POOL_FACTOR is large enough such that the
* RAND_POOL can store a random input which has a lousy entropy rate of
* 8/256 (= 0.03125) bits per byte. This input will be sent through the
* derivation function which 'compresses' the low quality input into a
* high quality output.
*
* The factor 1.5 below is the pessimistic estimate for the extra amount
* of entropy required when no get_nonce() callback is defined.
*/
# define RAND_POOL_FACTOR 256
# define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \
3 * (RAND_DRBG_STRENGTH / 16))
/*
* = (RAND_POOL_FACTOR * \
* 1.5 * (RAND_DRBG_STRENGTH / 8))
*/
/*
* Initial allocation minimum.
*
* There is a distinction between the secure and normal allocation minimums.
* Ideally, the secure allocation size should be a power of two. The normal
* allocation size doesn't have any such restriction.
*
* The secure value is based on 128 bits of secure material, which is 16 bytes.
* Typically, the DRBGs will set a minimum larger than this so optimal
* allocation ought to take place (for full quality seed material).
*
* The normal value has been chosen by noticing that the rand_drbg_get_nonce
* function is usually the largest of the built in allocation (twenty four
* bytes and then appending another sixteen bytes). This means the buffer ends
* with 40 bytes. The value of forty eight is comfortably above this which
* allows some slack in the platform specific values used.
*/
# define RAND_POOL_MIN_ALLOCATION(secure) ((secure) ? 16 : 48)
/*
* The 'random pool' acts as a dumb container for collecting random
* input from various entropy sources. 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.
*/
typedef 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 */
int attached; /* true pool was attached to existing buffer */
int secure; /* 1: allocated on the secure heap, 0: otherwise */
size_t min_len; /* minimum number of random bytes requested */
size_t max_len; /* maximum number of random bytes (allocated buffer size) */
size_t alloc_len; /* current number of bytes allocated */
size_t entropy; /* current entropy count in bits */
size_t entropy_requested; /* requested entropy count in bits */
} RAND_POOL;
RAND_POOL *rand_pool_new(int entropy_requested, int secure,
size_t min_len, size_t max_len);
RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
size_t entropy);
void rand_pool_free(RAND_POOL *pool);
const unsigned char *rand_pool_buffer(RAND_POOL *pool);
unsigned char *rand_pool_detach(RAND_POOL *pool);
void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer);
size_t rand_pool_entropy(RAND_POOL *pool);
size_t rand_pool_length(RAND_POOL *pool);
size_t rand_pool_entropy_available(RAND_POOL *pool);
size_t rand_pool_entropy_needed(RAND_POOL *pool);
/* |entropy_factor| expresses how many bits of data contain 1 bit of entropy */
size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor);
size_t rand_pool_bytes_remaining(RAND_POOL *pool);
int rand_pool_add(RAND_POOL *pool,
const unsigned char *buffer, size_t len, size_t entropy);
unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len);
int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy);
#endif /* OSSL_PROVIDER_RAND_POOL_H */

View File

@ -1,5 +1,5 @@
/*
* Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
* 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
@ -7,3 +7,406 @@
* 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) {
RANDerr(RAND_F_RAND_POOL_NEW, 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) {
RANDerr(RAND_F_RAND_POOL_NEW, 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) {
RANDerr(RAND_F_RAND_POOL_ATTACH, 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) {
RANDerr(RAND_F_RAND_POOL_GROW, 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) {
RANDerr(RAND_F_RAND_POOL_GROW, 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) {
RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, 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 */
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;
/*
* 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) {
RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
return 0;
}
if (pool->buffer == NULL) {
RANDerr(RAND_F_RAND_POOL_ADD, 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) {
RANDerr(RAND_F_RAND_POOL_ADD, 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) {
RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
return NULL;
}
if (pool->buffer == NULL) {
RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, 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) {
RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
return 0;
}
if (len > 0) {
pool->len += len;
pool->entropy += entropy;
}
return 1;
}

View File

@ -9,7 +9,7 @@
#include "internal/cryptlib.h"
#include <openssl/opensslconf.h>
#include "crypto/rand_pool.h"
#include "prov/rand_pool.h"
#ifdef OPENSSL_RAND_SEED_RDCPU
size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);

View File

@ -9,7 +9,7 @@
#include "internal/cryptlib.h"
#include <openssl/opensslconf.h>
#include "crypto/rand_pool.h"
#include "prov/rand_pool.h"
#ifdef OPENSSL_RAND_SEED_RDTSC
/*

View File

@ -15,11 +15,11 @@
#include "internal/cryptlib.h"
#include <openssl/rand.h>
#include <openssl/crypto.h>
#include "crypto/rand_pool.h"
#include "prov/rand_pool.h"
#include "crypto/rand.h"
#include <stdio.h>
#include "internal/dso.h"
#include "seeding.h"
#include "prov/seeding.h"
#ifdef __linux
# include <sys/syscall.h>

View File

@ -14,8 +14,8 @@
#include "internal/cryptlib.h"
#include <openssl/rand.h>
#include "crypto/rand.h"
#include "crypto/rand_pool.h"
#include "seeding.h"
#include "prov/rand_pool.h"
#include "prov/seeding.h"
#include <descrip.h>
#include <dvidef.h>
#include <jpidef.h>

View File

@ -10,10 +10,10 @@
#include <openssl/opensslconf.h>
#include <openssl/rand.h>
#include "crypto/rand_pool.h"
#include "prov/rand_pool.h"
#include "crypto/rand.h"
#include "internal/cryptlib.h"
#include "seeding.h"
#include "prov/seeding.h"
#include <version.h>
#include <taskLib.h>

View File

@ -9,9 +9,10 @@
#include "internal/cryptlib.h"
#include <openssl/rand.h>
#include "crypto/rand_pool.h"
#include "prov/rand_pool.h"
#include "crypto/rand.h"
#include "seeding.h"
#include "prov/seeding.h"
#if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32)
# ifndef OPENSSL_RAND_SEED_OS