Commit 939ef2ea authored by Bernd Edlinger's avatar Bernd Edlinger
Browse files

Avoid two memory allocations in each RAND_DRBG_bytes 



Reviewed-by: default avatarMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7518)
parent c40c1ef4

crypto/include/internal/rand_int.h

+3 −2
Original line number Diff line number Diff line
@@ -45,9 +45,9 @@ size_t rand_drbg_get_nonce(RAND_DRBG *drbg, 
void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,

                             unsigned char *out, size_t outlen);



size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len);

size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout);



void rand_drbg_cleanup_additional_data(unsigned char *out, size_t outlen);

void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out);



/*

 * RAND_POOL functions
@@ -59,6 +59,7 @@ 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);

crypto/rand/drbg_lib.c

+23 −5
Original line number Diff line number Diff line
@@ -109,6 +109,13 @@ int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags) 
        flags = rand_drbg_flags;

    }



    /* If set is called multiple times - clear the old one */

    if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {

        drbg->meth->uninstantiate(drbg);

        rand_pool_free(drbg->adin_pool);

        drbg->adin_pool = NULL;

    }



    drbg->state = DRBG_UNINITIALISED;

    drbg->flags = flags;

    drbg->type = type;
@@ -122,6 +129,7 @@ int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags) 
        return 0;

    case 0:

        /* Uninitialized; that's okay. */

        drbg->meth = NULL;

        return 1;

    case NID_aes_128_ctr:

    case NID_aes_192_ctr:
@@ -259,6 +267,7 @@ void RAND_DRBG_free(RAND_DRBG *drbg) 


    if (drbg->meth != NULL)

        drbg->meth->uninstantiate(drbg);

    rand_pool_free(drbg->adin_pool);

    CRYPTO_THREAD_lock_free(drbg->lock);

    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
@@ -650,9 +659,18 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen) 
    unsigned char *additional = NULL;

    size_t additional_len;

    size_t chunk;

    size_t ret;

    size_t ret = 0;



    if (drbg->adin_pool == NULL) {

        if (drbg->type == 0)

            goto err;

        drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);

        if (drbg->adin_pool == NULL)

            goto err;

    }



    additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);

    additional_len = rand_drbg_get_additional_data(drbg->adin_pool,

                                                   &additional);



    for ( ; outlen > 0; outlen -= chunk, out += chunk) {

        chunk = outlen;
@@ -665,8 +683,8 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen) 
    ret = 1;



 err:

    if (additional_len != 0)

        OPENSSL_secure_clear_free(additional, additional_len);

    if (additional != NULL)

        rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);



    return ret;

}

crypto/rand/rand_lcl.h

+5 −0
Original line number Diff line number Diff line
@@ -185,6 +185,11 @@ struct rand_drbg_st { 
     */

    struct rand_pool_st *pool;



    /*

     * Auxiliary pool for additional data.

     */

    struct rand_pool_st *adin_pool;



    /*

     * The following parameters are setup by the per-type "init" function.

     *

crypto/rand/rand_lib.c

+25 −12
Original line number Diff line number Diff line
@@ -279,14 +279,9 @@ void rand_drbg_cleanup_nonce(RAND_DRBG *drbg, 
 * On success it allocates a buffer at |*pout| and returns the length of

 * the data. The buffer should get freed using OPENSSL_secure_clear_free().

 */

size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)

size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)

{

    size_t ret = 0;

    RAND_POOL *pool;



    pool = rand_pool_new(0, 0, max_len);

    if (pool == NULL)

        return 0;



    if (rand_pool_add_additional_data(pool) == 0)

        goto err;
@@ -295,14 +290,12 @@ size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len) 
    *pout = rand_pool_detach(pool);



 err:

    rand_pool_free(pool);



    return ret;

}



void rand_drbg_cleanup_additional_data(unsigned char *out, size_t outlen)

void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)

{

    OPENSSL_secure_clear_free(out, outlen);

    rand_pool_reattach(pool, out);

}



void rand_fork(void)
@@ -536,17 +529,27 @@ size_t rand_pool_length(RAND_POOL *pool) 
/*

 * 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().

 * 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->len = 0;

    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
@@ -643,6 +646,11 @@ int rand_pool_add(RAND_POOL *pool, 
        return 0;

    }



    if (pool->buffer == NULL) {

        RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);

        return 0;

    }



    if (len > 0) {

        memcpy(pool->buffer + pool->len, buffer, len);

        pool->len += len;
@@ -674,6 +682,11 @@ unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len) 
        return NULL;

    }



    if (pool->buffer == NULL) {

        RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, ERR_R_INTERNAL_ERROR);

        return 0;

    }



    return pool->buffer + pool->len;

}