Commit 0b14a5b7 authored by Kurt Roeckx's avatar Kurt Roeckx
Browse files

Don't auto-instantiate a DRBG when trying to use it and it's not 



The one creating the DRBG should instantiate it, it's there that we
know which parameters we should use to instantiate it.

This splits the rand init in two parts to avoid a deadlock
because when the global drbg is created it wands to call
rand_add on the global rand method.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
GH: #4268
parent b2317174

crypto/include/internal/rand_int.h

+1 −0
Original line number Diff line number Diff line
@@ -18,4 +18,5 @@ 
#include <openssl/rand.h>



void rand_cleanup_int(void);

void rand_cleanup_drbg_int(void);

void rand_fork(void);

crypto/init.c

+1 −0
Original line number Diff line number Diff line
@@ -488,6 +488,7 @@ void OPENSSL_cleanup(void) 
     * obj_cleanup_int() must be called last

     */

    rand_cleanup_int();

    rand_cleanup_drbg_int();

    conf_modules_free_int();

#ifndef OPENSSL_NO_ENGINE

    engine_cleanup_int();

crypto/rand/drbg_lib.c

+96 −28
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <openssl/err.h>

#include <openssl/rand.h>

#include "rand_lcl.h"

#include "internal/thread_once.h"

#include "internal/rand_int.h"



/*

 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
@@ -25,6 +27,8 @@ 
 * a much bigger deal than just re-setting an allocated resource.)

 */



static CRYPTO_ONCE rand_init_drbg = CRYPTO_ONCE_STATIC_INIT;



/*

 * Set/initialize |drbg| to be of type |nid|, with optional |flags|.

 * Return -2 if the type is not supported, 1 on success and -1 on
@@ -76,18 +80,9 @@ RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent) 
        goto err;



    if (parent != NULL) {

        if (parent->state == DRBG_UNINITIALISED

                && RAND_DRBG_instantiate(parent, NULL, 0) == 0)

            goto err;

        if (!RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_parent,

                                     drbg_release_entropy,

                                     NULL, NULL)

                /*

                 * Add in our address.  Note we are adding the pointer

                 * itself, not its contents!

                 */

                || !RAND_DRBG_instantiate(drbg,

                                          (unsigned char*)&drbg, sizeof(drbg)))

                                     NULL, NULL))

            goto err;

    }
@@ -98,17 +93,12 @@ err: 
    return NULL;

}



RAND_DRBG *RAND_DRBG_get0_global(void)

{

    return &rand_drbg;

}



/*

 * Uninstantiate |drbg| and free all memory.

 */

void RAND_DRBG_free(RAND_DRBG *drbg)

{

    /* The global DRBG is free'd by rand_cleanup_int() */

    /* The global DRBG is free'd by rand_cleanup_drbg_int() */

    if (drbg == NULL || drbg == &rand_drbg)

        return;
@@ -340,28 +330,80 @@ void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx) 
 * global DRBG.  They lock.

 */



/*

 * Creates a global DRBG with default settings.

 * Returns 1 on success, 0 on failure

 */

static int setup_drbg(RAND_DRBG *drbg)

{

    int ret = 1;



    drbg->lock = CRYPTO_THREAD_lock_new();

    ret &= drbg->lock != NULL;

    drbg->size = RANDOMNESS_NEEDED;

    drbg->secure = CRYPTO_secure_malloc_initialized();

    /* If you change these parameters, see RANDOMNESS_NEEDED */

    ret &= RAND_DRBG_set(drbg,

                         NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;

    ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,

                                   drbg_release_entropy, NULL, NULL) == 1;

    ret &= RAND_DRBG_instantiate(drbg, NULL, 0) == 1;

    return ret;

}



/*

 * Initialize the global DRBGs on first use.

 * Returns 1 on success, 0 on failure.

 */

DEFINE_RUN_ONCE_STATIC(do_rand_init_drbg)

{

    int ret = 1;



    ret &= setup_drbg(&rand_drbg);

    ret &= setup_drbg(&priv_drbg);



    return ret;

}



/* Clean up a DRBG and free it */

static void free_drbg(RAND_DRBG *drbg)

{

    CRYPTO_THREAD_lock_free(drbg->lock);

    RAND_DRBG_uninstantiate(drbg);

}



/* Clean up the global DRBGs before exit */

void rand_cleanup_drbg_int(void)

{

    free_drbg(&rand_drbg);

    free_drbg(&priv_drbg);

}



static int drbg_bytes(unsigned char *out, int count)

{

    int ret = 0;

    size_t chunk;

    RAND_DRBG *drbg = RAND_DRBG_get0_global();



    CRYPTO_THREAD_write_lock(rand_drbg.lock);

    if (rand_drbg.state == DRBG_UNINITIALISED

            && RAND_DRBG_instantiate(&rand_drbg, NULL, 0) == 0)

    if (drbg == NULL)

        return 0;



    CRYPTO_THREAD_write_lock(drbg->lock);

    if (drbg->state == DRBG_UNINITIALISED)

        goto err;



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

        chunk = count;

        if (chunk > rand_drbg.max_request)

            chunk = rand_drbg.max_request;

        ret = RAND_DRBG_generate(&rand_drbg, out, chunk, 0, NULL, 0);

        if (chunk > drbg->max_request)

            chunk = drbg->max_request;

        ret = RAND_DRBG_generate(drbg, out, chunk, 0, NULL, 0);

        if (!ret)

            goto err;

    }

    ret = 1;



err:

    CRYPTO_THREAD_unlock(rand_drbg.lock);

    CRYPTO_THREAD_unlock(drbg->lock);

    return ret;

}
@@ -396,15 +438,41 @@ static int drbg_seed(const void *buf, int num) 
static int drbg_status(void)

{

    int ret;

    RAND_DRBG *drbg = RAND_DRBG_get0_global();



    if (drbg == NULL)

        return 0;



    CRYPTO_THREAD_write_lock(rand_drbg.lock);

    if (rand_drbg.state == DRBG_UNINITIALISED)

        RAND_DRBG_instantiate(&rand_drbg, NULL, 0);

    ret = rand_drbg.state == DRBG_READY ? 1 : 0;

    CRYPTO_THREAD_unlock(rand_drbg.lock);

    CRYPTO_THREAD_write_lock(drbg->lock);

    ret = drbg->state == DRBG_READY ? 1 : 0;

    CRYPTO_THREAD_unlock(drbg->lock);

    return ret;

}



/*

 * Get the global public DRBG.

 * Returns pointer to the DRBG on success, NULL on failure.

 */

RAND_DRBG *RAND_DRBG_get0_global(void)

{

    if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg))

        return NULL;



    return &rand_drbg;

}



/*

 * Get the global private DRBG.

 * Returns pointer to the DRBG on success, NULL on failure.

 */

RAND_DRBG *RAND_DRBG_get0_priv_global(void)

{

    if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg))

        return NULL;



    return &priv_drbg;

}



RAND_DRBG rand_drbg; /* The default global DRBG. */

RAND_DRBG priv_drbg; /* The global private-key DRBG. */

crypto/rand/rand_lib.c

+5 −34
Original line number Diff line number Diff line
@@ -172,32 +172,6 @@ void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out, size_t outlen) 
        OPENSSL_clear_free(out, outlen);

}





/*

 * Set up a global DRBG.

 */

static int setup_drbg(RAND_DRBG *drbg)

{

    int ret = 1;



    drbg->lock = CRYPTO_THREAD_lock_new();

    ret &= drbg->lock != NULL;

    drbg->size = RANDOMNESS_NEEDED;

    drbg->secure = CRYPTO_secure_malloc_initialized();

    /* If you change these parameters, see RANDOMNESS_NEEDED */

    ret &= RAND_DRBG_set(drbg,

                         NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;

    ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,

                                   drbg_release_entropy, NULL, NULL) == 1;

    return ret;

}



static void free_drbg(RAND_DRBG *drbg)

{

    CRYPTO_THREAD_lock_free(drbg->lock);

    RAND_DRBG_uninstantiate(drbg);

}



void rand_fork()

{

    rand_fork_count++;
@@ -223,8 +197,6 @@ DEFINE_RUN_ONCE_STATIC(do_rand_init) 
        ? OPENSSL_secure_malloc(rand_bytes.size)

        : OPENSSL_malloc(rand_bytes.size);

    ret &= rand_bytes.buff != NULL;

    ret &= setup_drbg(&rand_drbg);

    ret &= setup_drbg(&priv_drbg);

    return ret;

}
@@ -244,8 +216,6 @@ void rand_cleanup_int(void) 
        OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);

    else

        OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);

    free_drbg(&rand_drbg);

    free_drbg(&priv_drbg);

}



/*
@@ -357,15 +327,16 @@ void RAND_add(const void *buf, int num, double randomness) 
int RAND_priv_bytes(unsigned char *buf, int num)

{

    const RAND_METHOD *meth = RAND_get_rand_method();

    RAND_DRBG *drbg;



    if (meth != RAND_OpenSSL())

        return RAND_bytes(buf, num);



    if (priv_drbg.state == DRBG_UNINITIALISED

            && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)

    drbg = RAND_DRBG_get0_priv_global();

    if (drbg == NULL)

        return 0;

    return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0);



    return RAND_DRBG_generate(drbg, buf, num, 0, NULL, 0);

}



int RAND_bytes(unsigned char *buf, int num)

include/internal/rand.h

+1 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen, 
                       const unsigned char *adin, size_t adinlen);

int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, int interval);

RAND_DRBG *RAND_DRBG_get0_global(void);

RAND_DRBG *RAND_DRBG_get0_priv_global(void);



/*

 * EXDATA