Commit 9f08a1c6 authored by Rich Salz's avatar Rich Salz
Browse files

Install custom RAND_METHOD for fuzzing 



Instead of setting a "magic" global variable to force RAND to keep
consistent state and always generate the same bytestream, have
the fuzzing code install its own RAND_METHOD that does this.  For
BN_RAND_DEBUG, we just don't do it; that debugging was about mucking
with BN's internal representation, not requiring predictable rand
bytes.

Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4025)
parent 43405889

crypto/rand/ossl_rand.c

+0 −23
Original line number Diff line number Diff line
@@ -27,10 +27,6 @@ 
#include <internal/thread_once.h>

#include "rand_lcl.h"



#if defined(BN_DEBUG) || defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)

# define PREDICT 1

#endif



#define STATE_SIZE      1023



typedef struct ossl_rand_state_st OSSL_RAND_STATE;
@@ -59,10 +55,6 @@ static unsigned int crypto_lock_rand = 0; 
 */

static CRYPTO_THREAD_ID locking_threadid;



#ifdef PREDICT

int rand_predictable = 0;

#endif



static int rand_hw_seed(EVP_MD_CTX *ctx);



static void rand_thread_cleanup(void *arg)
@@ -112,11 +104,6 @@ static int rand_add(const void *buf, int num, double add) 
    if (!num)

        return 1;



#ifdef PREDICT

    if (rand_predictable)

        return 1;

#endif



    /*

     * (Based on the rand(3) manpage)

     *
@@ -297,16 +284,6 @@ static int rand_bytes(unsigned char *buf, int num) 
    gettimeofday(&tv, NULL);

#endif



#ifdef PREDICT

    if (rand_predictable) {

        unsigned char val = 1;



        for (i = 0; i < num; i++)

            buf[i] = val++;

        return (1);

    }

#endif



    if (num <= 0)

        return 1;

fuzz/asn1.c

+1 −11
Original line number Diff line number Diff line
@@ -31,11 +31,6 @@ 
#include <openssl/rand.h>

#include "fuzzer.h"



#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

extern int rand_predictable;

#endif

#define ENTROPY_NEEDED 32



static ASN1_ITEM_EXP *item_type[] = {

    ASN1_ITEM_ref(ACCESS_DESCRIPTION),

#ifndef OPENSSL_NO_RFC3779
@@ -216,12 +211,7 @@ int FuzzerInitialize(int *argc, char ***argv) 
    OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);

    ERR_get_state();

    CRYPTO_free_ex_index(0, -1);

    RAND_add("", 1, ENTROPY_NEEDED);

    RAND_status();



#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    rand_predictable = 1;

#endif

    FuzzerSetRand();



    return 1;

}

fuzz/client.c

+1 −11
Original line number Diff line number Diff line
@@ -18,11 +18,6 @@ 
#include <openssl/err.h>

#include "fuzzer.h"



#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

extern int rand_predictable;

#endif

#define ENTROPY_NEEDED 32



/* unused, to avoid warning. */

static int idx;
@@ -50,16 +45,11 @@ int FuzzerInitialize(int *argc, char ***argv) 
    ERR_get_state();

    CRYPTO_free_ex_index(0, -1);

    idx = SSL_get_ex_data_X509_STORE_CTX_idx();

    RAND_add("", 1, ENTROPY_NEEDED);

    RAND_status();

    FuzzerSetRand();

    comp_methods = SSL_COMP_get_compression_methods();

    OPENSSL_sk_sort((OPENSSL_STACK *)comp_methods);





#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    rand_predictable = 1;

#endif



    return 1;

}

fuzz/fuzzer.h

+1 −0
Original line number Diff line number Diff line
@@ -11,3 +11,4 @@ 
int FuzzerTestOneInput(const uint8_t *buf, size_t len);

int FuzzerInitialize(int *argc, char ***argv);

void FuzzerCleanup(void);

void FuzzerSetRand(void);

fuzz/server.c

+1 −11
Original line number Diff line number Diff line
@@ -465,11 +465,6 @@ static const char DSACertPEM[] = { 
};

#endif



#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

extern int rand_predictable;

#endif

#define ENTROPY_NEEDED 32



/* unused, to avoid warning. */

static int idx;
@@ -497,16 +492,11 @@ int FuzzerInitialize(int *argc, char ***argv) 
    ERR_get_state();

    CRYPTO_free_ex_index(0, -1);

    idx = SSL_get_ex_data_X509_STORE_CTX_idx();

    RAND_add("", 1, ENTROPY_NEEDED);

    RAND_status();

    FuzzerSetRand();

    comp_methods = SSL_COMP_get_compression_methods();

    OPENSSL_sk_sort((OPENSSL_STACK *)comp_methods);





#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    rand_predictable = 1;

#endif



    return 1;

}