diff options
author | Pauli <paul.dale@oracle.com> | 2020-05-12 12:20:28 +1000 |
---|---|---|
committer | Pauli <paul.dale@oracle.com> | 2020-06-24 20:05:41 +1000 |
commit | bcdea3badfdbcdcd22591c5ea1744a19fb723fcf (patch) | |
tree | c0541597348a9000f63dba57737462e725e81001 /providers | |
parent | e1c5b1f6b4b92b819992cab702b6fdfc2960461c (diff) |
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)
Diffstat (limited to 'providers')
-rw-r--r-- | providers/implementations/include/prov/rand_pool.h | 108 | ||||
-rw-r--r-- | providers/implementations/include/prov/seeding.h (renamed from providers/implementations/rands/seeding/seeding.h) | 0 | ||||
-rw-r--r-- | providers/implementations/rands/rand_pool.c | 405 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_cpu_x86.c | 2 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_tsc.c | 2 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_unix.c | 4 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_vms.c | 4 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_vxworks.c | 4 | ||||
-rw-r--r-- | providers/implementations/rands/seeding/rand_win.c | 5 |
9 files changed, 523 insertions, 11 deletions
diff --git a/providers/implementations/include/prov/rand_pool.h b/providers/implementations/include/prov/rand_pool.h new file mode 100644 index 0000000000..f476604770 --- /dev/null +++ b/providers/implementations/include/prov/rand_pool.h @@ -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 */ diff --git a/providers/implementations/rands/seeding/seeding.h b/providers/implementations/include/prov/seeding.h index bd0a57a769..bd0a57a769 100644 --- a/providers/implementations/rands/seeding/seeding.h +++ b/providers/implementations/include/prov/seeding.h diff --git a/providers/implementations/rands/rand_pool.c b/providers/implementations/rands/rand_pool.c index 71b71190e8..cf0e6774a5 100644 --- a/providers/implementations/rands/rand_pool.c +++ b/providers/implementations/rands/rand_pool.c @@ -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; +} diff --git a/providers/implementations/rands/seeding/rand_cpu_x86.c b/providers/implementations/rands/seeding/rand_cpu_x86.c index 3b276c8f54..ba0f716426 100644 --- a/providers/implementations/rands/seeding/rand_cpu_x86.c +++ b/providers/implementations/rands/seeding/rand_cpu_x86.c @@ -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); diff --git a/providers/implementations/rands/seeding/rand_tsc.c b/providers/implementations/rands/seeding/rand_tsc.c index 2121abe499..dd69aa438f 100644 --- a/providers/implementations/rands/seeding/rand_tsc.c +++ b/providers/implementations/rands/seeding/rand_tsc.c @@ -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 /* diff --git a/providers/implementations/rands/seeding/rand_unix.c b/providers/implementations/rands/seeding/rand_unix.c index 050b3e9a18..77c5d26142 100644 --- a/providers/implementations/rands/seeding/rand_unix.c +++ b/providers/implementations/rands/seeding/rand_unix.c @@ -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> diff --git a/providers/implementations/rands/seeding/rand_vms.c b/providers/implementations/rands/seeding/rand_vms.c index 761dad1168..7adf3e718a 100644 --- a/providers/implementations/rands/seeding/rand_vms.c +++ b/providers/implementations/rands/seeding/rand_vms.c @@ -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> diff --git a/providers/implementations/rands/seeding/rand_vxworks.c b/providers/implementations/rands/seeding/rand_vxworks.c index ec9004c06c..f601f77a47 100644 --- a/providers/implementations/rands/seeding/rand_vxworks.c +++ b/providers/implementations/rands/seeding/rand_vxworks.c @@ -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> diff --git a/providers/implementations/rands/seeding/rand_win.c b/providers/implementations/rands/seeding/rand_win.c index d5c5b59269..605ac6cfe1 100644 --- a/providers/implementations/rands/seeding/rand_win.c +++ b/providers/implementations/rands/seeding/rand_win.c @@ -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 |