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Merge remote-tracking branch 'restricted/pr/510' into development-restricted-proposed

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This commit is contained in:
Simon Butcher 2018-11-07 13:02:27 +00:00
commit cdd1a6c872
8 changed files with 255 additions and 51 deletions
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88
library/bignum.c
View file

@ -2056,12 +2056,12 @@ cleanup:
/*
* Miller-Rabin pseudo-primality test (HAC 4.24)
*/
static int mpi_miller_rabin( const mbedtls_mpi *X,
static int mpi_miller_rabin( const mbedtls_mpi *X, size_t rounds,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret, count;
size_t i, j, k, n, s;
size_t i, j, k, s;
mbedtls_mpi W, R, T, A, RR;
mbedtls_mpi_init( &W ); mbedtls_mpi_init( &R ); mbedtls_mpi_init( &T ); mbedtls_mpi_init( &A );
@ -2077,27 +2077,12 @@ static int mpi_miller_rabin( const mbedtls_mpi *X,
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &R, s ) );
i = mbedtls_mpi_bitlen( X );
/*
* HAC, table 4.4
*/
n = ( ( i >= 1300 ) ? 2 : ( i >= 850 ) ? 3 :
( i >= 650 ) ? 4 : ( i >= 350 ) ? 8 :
( i >= 250 ) ? 12 : ( i >= 150 ) ? 18 : 27 );
for( i = 0; i < n; i++ )
for( i = 0; i < rounds; i++ )
{
/*
* pick a random A, 1 < A < |X| - 1
*/
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &A, X->n * ciL, f_rng, p_rng ) );
if( mbedtls_mpi_cmp_mpi( &A, &W ) >= 0 )
{
j = mbedtls_mpi_bitlen( &A ) - mbedtls_mpi_bitlen( &W );
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &A, j + 1 ) );
}
A.p[0] |= 3;
count = 0;
do {
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &A, X->n * ciL, f_rng, p_rng ) );
@ -2105,7 +2090,7 @@ static int mpi_miller_rabin( const mbedtls_mpi *X,
j = mbedtls_mpi_bitlen( &A );
k = mbedtls_mpi_bitlen( &W );
if (j > k) {
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &A, j - k ) );
A.p[A.n - 1] &= ( (mbedtls_mpi_uint) 1 << ( k - ( A.n - 1 ) * biL - 1 ) ) - 1;
}
if (count++ > 30) {
@ -2160,9 +2145,9 @@ cleanup:
/*
* Pseudo-primality test: small factors, then Miller-Rabin
*/
int mbedtls_mpi_is_prime( const mbedtls_mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
int mbedtls_mpi_is_prime_ext( const mbedtls_mpi *X, int rounds,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
mbedtls_mpi XX;
@ -2186,17 +2171,34 @@ int mbedtls_mpi_is_prime( const mbedtls_mpi *X,
return( ret );
}
return( mpi_miller_rabin( &XX, f_rng, p_rng ) );
return( mpi_miller_rabin( &XX, rounds, f_rng, p_rng ) );
}
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
/*
* Pseudo-primality test, error probability 2^-80
*/
int mbedtls_mpi_is_prime( const mbedtls_mpi *X,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
/*
* In the past our key generation aimed for an error rate of at most
* 2^-80. Since this function is deprecated, aim for the same certainty
* here as well.
*/
return mbedtls_mpi_is_prime_ext( X, 40, f_rng, p_rng );
}
#endif
/*
* Prime number generation
*
* If dh_flag is 0 and nbits is at least 1024, then the procedure
* follows the RSA probably-prime generation method of FIPS 186-4.
* NB. FIPS 186-4 only allows the specific bit lengths of 1024 and 1536.
* To generate an RSA key in a way recommended by FIPS 186-4, both primes must
* be either 1024 bits or 1536 bits long, and flags must contain
* MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR.
*/
int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag,
int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int flags,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
@ -2209,6 +2211,7 @@ int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag,
#endif
int ret = MBEDTLS_ERR_MPI_NOT_ACCEPTABLE;
size_t k, n;
int rounds;
mbedtls_mpi_uint r;
mbedtls_mpi Y;
@ -2219,6 +2222,27 @@ int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag,
n = BITS_TO_LIMBS( nbits );
if( ( flags & MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR ) == 0 )
{
/*
* 2^-80 error probability, number of rounds chosen per HAC, table 4.4
*/
rounds = ( ( nbits >= 1300 ) ? 2 : ( nbits >= 850 ) ? 3 :
( nbits >= 650 ) ? 4 : ( nbits >= 350 ) ? 8 :
( nbits >= 250 ) ? 12 : ( nbits >= 150 ) ? 18 : 27 );
}
else
{
/*
* 2^-100 error probability, number of rounds computed based on HAC,
* fact 4.48
*/
rounds = ( ( nbits >= 1450 ) ? 4 : ( nbits >= 1150 ) ? 5 :
( nbits >= 1000 ) ? 6 : ( nbits >= 850 ) ? 7 :
( nbits >= 750 ) ? 8 : ( nbits >= 500 ) ? 13 :
( nbits >= 250 ) ? 28 : ( nbits >= 150 ) ? 40 : 51 );
}
while( 1 )
{
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( X, n * ciL, f_rng, p_rng ) );
@ -2229,9 +2253,9 @@ int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag,
if( k > nbits ) MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( X, k - nbits ) );
X->p[0] |= 1;
if( dh_flag == 0 )
if( ( flags & MBEDTLS_MPI_GEN_PRIME_FLAG_DH ) == 0 )
{
ret = mbedtls_mpi_is_prime( X, f_rng, p_rng );
ret = mbedtls_mpi_is_prime_ext( X, rounds, f_rng, p_rng );
if( ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE )
goto cleanup;
@ -2264,8 +2288,10 @@ int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag,
*/
if( ( ret = mpi_check_small_factors( X ) ) == 0 &&
( ret = mpi_check_small_factors( &Y ) ) == 0 &&
( ret = mpi_miller_rabin( X, f_rng, p_rng ) ) == 0 &&
( ret = mpi_miller_rabin( &Y, f_rng, p_rng ) ) == 0 )
( ret = mpi_miller_rabin( X, rounds, f_rng, p_rng ) )
== 0 &&
( ret = mpi_miller_rabin( &Y, rounds, f_rng, p_rng ) )
== 0 )
goto cleanup;
if( ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE )

17
library/rsa.c
View file

@ -502,6 +502,7 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
{
int ret;
mbedtls_mpi H, G, L;
int prime_quality = 0;
if( f_rng == NULL || nbits < 128 || exponent < 3 )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
@ -509,6 +510,14 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
if( nbits % 2 )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
/*
* If the modulus is 1024 bit long or shorter, then the security strength of
* the RSA algorithm is less than or equal to 80 bits and therefore an error
* rate of 2^-80 is sufficient.
*/
if( nbits > 1024 )
prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR;
mbedtls_mpi_init( &H );
mbedtls_mpi_init( &G );
mbedtls_mpi_init( &L );
@ -523,11 +532,11 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
do
{
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1, 0,
f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1,
prime_quality, f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, 0,
f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1,
prime_quality, f_rng, p_rng ) );
/* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &H, &ctx->P, &ctx->Q ) );

9
library/rsa_internal.c
View file

@ -351,15 +351,20 @@ int mbedtls_rsa_validate_params( const mbedtls_mpi *N, const mbedtls_mpi *P,
*/
#if defined(MBEDTLS_GENPRIME)
/*
* When generating keys, the strongest security we support aims for an error
* rate of at most 2^-100 and we are aiming for the same certainty here as
* well.
*/
if( f_rng != NULL && P != NULL &&
( ret = mbedtls_mpi_is_prime( P, f_rng, p_rng ) ) != 0 )
( ret = mbedtls_mpi_is_prime_ext( P, 50, f_rng, p_rng ) ) != 0 )
{
ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
goto cleanup;
}
if( f_rng != NULL && Q != NULL &&
( ret = mbedtls_mpi_is_prime( Q, f_rng, p_rng ) ) != 0 )
( ret = mbedtls_mpi_is_prime_ext( Q, 50, f_rng, p_rng ) ) != 0 )
{
ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
goto cleanup;