Commit 35503b7c authored by Kurt Roeckx's avatar Kurt Roeckx
Browse files

Check the parent DRBG's strength 



We currently don't support the algorithm from NIST SP 800-90C
10.1.2 to use a weaker DRBG as source

Reviewed-by: default avatarDr. Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
GH: #5506
parent 3bc0ab06

crypto/err/openssl.txt

+2 −0
Original line number Diff line number Diff line
@@ -907,6 +907,7 @@ RAND_F_GET_ENTROPY:106:get_entropy 
RAND_F_RAND_BYTES:100:RAND_bytes

RAND_F_RAND_DRBG_ENABLE_LOCKING:119:rand_drbg_enable_locking

RAND_F_RAND_DRBG_GENERATE:107:RAND_DRBG_generate

RAND_F_RAND_DRBG_GET_ENTROPY:120:rand_drbg_get_entropy

RAND_F_RAND_DRBG_INSTANTIATE:108:RAND_DRBG_instantiate

RAND_F_RAND_DRBG_NEW:109:RAND_DRBG_new

RAND_F_RAND_DRBG_RESEED:110:RAND_DRBG_reseed
@@ -2300,6 +2301,7 @@ RAND_R_NOT_A_REGULAR_FILE:122:Not a regular file 
RAND_R_NOT_INSTANTIATED:115:not instantiated

RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED:128:no drbg implementation selected

RAND_R_PARENT_LOCKING_NOT_ENABLED:130:parent locking not enabled

RAND_R_PARENT_STRENGTH_TOO_WEAK:131:parent strength too weak

RAND_R_PERSONALISATION_STRING_TOO_LONG:116:personalisation string too long

RAND_R_PRNG_NOT_SEEDED:100:PRNG not seeded

RAND_R_RANDOM_POOL_OVERFLOW:125:random pool overflow

crypto/rand/drbg_lib.c

+9 −0
Original line number Diff line number Diff line
@@ -178,6 +178,15 @@ static RAND_DRBG *rand_drbg_new(int secure, 
    if (RAND_DRBG_set(drbg, type, flags) == 0)

        goto err;



    if (parent != NULL && drbg->strength > parent->strength) {

        /*

         * We currently don't support the algorithm from NIST SP 800-90C

         * 10.1.2 to use a weaker DRBG as source

         */

        RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);

        goto err;

    }



    if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,

                                 rand_drbg_cleanup_entropy,

                                 NULL, NULL))

crypto/rand/rand_err.c

+4 −0
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ static const ERR_STRING_DATA RAND_str_functs[] = { 
     "rand_drbg_enable_locking"},

    {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_GENERATE, 0),

     "RAND_DRBG_generate"},

    {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_GET_ENTROPY, 0),

     "rand_drbg_get_entropy"},

    {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_INSTANTIATE, 0),

     "RAND_DRBG_instantiate"},

    {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_NEW, 0), "RAND_DRBG_new"},
@@ -86,6 +88,8 @@ static const ERR_STRING_DATA RAND_str_reasons[] = { 
    "no drbg implementation selected"},

    {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PARENT_LOCKING_NOT_ENABLED),

    "parent locking not enabled"},

    {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PARENT_STRENGTH_TOO_WEAK),

    "parent strength too weak"},

    {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PERSONALISATION_STRING_TOO_LONG),

    "personalisation string too long"},

    {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PRNG_NOT_SEEDED), "PRNG not seeded"},

crypto/rand/rand_lib.c

+11 −1
Original line number Diff line number Diff line
@@ -176,8 +176,18 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg, 
{

    size_t ret = 0;

    size_t entropy_available = 0;

    RAND_POOL *pool = RAND_POOL_new(entropy, min_len, max_len);

    RAND_POOL *pool;



    if (drbg->parent && drbg->strength > drbg->parent->strength) {

        /*

         * We currently don't support the algorithm from NIST SP 800-90C

         * 10.1.2 to use a weaker DRBG as source

         */

        RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_R_PARENT_STRENGTH_TOO_WEAK);

        return 0;

    }



    pool = RAND_POOL_new(entropy, min_len, max_len);

    if (pool == NULL)

        return 0;

include/openssl/randerr.h

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ int ERR_load_RAND_strings(void); 
# define RAND_F_RAND_BYTES                                100

# define RAND_F_RAND_DRBG_ENABLE_LOCKING                  119

# define RAND_F_RAND_DRBG_GENERATE                        107

# define RAND_F_RAND_DRBG_GET_ENTROPY                     120

# define RAND_F_RAND_DRBG_INSTANTIATE                     108

# define RAND_F_RAND_DRBG_NEW                             109

# define RAND_F_RAND_DRBG_RESEED                          110
@@ -67,6 +68,7 @@ int ERR_load_RAND_strings(void); 
# define RAND_R_NOT_INSTANTIATED                          115

# define RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED           128

# define RAND_R_PARENT_LOCKING_NOT_ENABLED                130

# define RAND_R_PARENT_STRENGTH_TOO_WEAK                  131

# define RAND_R_PERSONALISATION_STRING_TOO_LONG           116

# define RAND_R_PRNG_NOT_SEEDED                           100

# define RAND_R_RANDOM_POOL_OVERFLOW                      125