Introduce muladd_restartable() and its sub-context

Only the administrative parts for now, not actually restartable so far.
This commit is contained in:
Manuel Pégourié-Gonnard 2017-04-20 13:36:18 +02:00
parent a08cd1a77f
commit 54dd6527f0
4 changed files with 199 additions and 13 deletions

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@ -179,6 +179,13 @@ mbedtls_ecp_keypair;
*/
typedef struct mbedtls_ecp_restart_mul mbedtls_ecp_restart_mul_ctx;
/**
* \brief Internal restart context for ecp_muladd()
*
* \note Opaque struct
*/
typedef struct mbedtls_ecp_restart_muladd mbedtls_ecp_restart_muladd_ctx;
/**
* \brief General context for resuming ECC operations
*/
@ -187,6 +194,7 @@ typedef struct
unsigned ops_done; /*!< current ops count */
unsigned depth; /*!< call depth (0 = top-level) */
mbedtls_ecp_restart_mul_ctx *rsm; /*!< ecp_mul_comb() sub-context */
mbedtls_ecp_restart_muladd_ctx *ma; /*!< ecp_muladd() sub-context */
} mbedtls_ecp_restart_ctx;
#endif /* MBEDTLS_ECP_EARLY_RETURN */
@ -654,6 +662,33 @@ int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
const mbedtls_mpi *n, const mbedtls_ecp_point *Q );
#if defined(MBEDTLS_ECP_EARLY_RETURN)
/**
* \brief Restartable version of \c mbedtls_ecp_muladd()
*
* \note Performs the same job as \c mbedtls_ecp_muladd(), but can
* return early and restart according to the limit set with
* \c mbedtls_ecp_set_max_ops() to reduce blocking.
*
* \param grp ECP group
* \param R Destination point
* \param m Integer by which to multiply P
* \param P Point to multiply by m
* \param n Integer by which to multiply Q
* \param Q Point to be multiplied by n
* \param rs_ctx Restart context
*
* \return See \c mbedtls_ecp_muladd(), or
* MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
* operations was reached: see \c mbedtls_ecp_set_max_ops().
*/
int mbedtls_ecp_muladd_restartable(
mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
const mbedtls_mpi *n, const mbedtls_ecp_point *Q,
mbedtls_ecp_restart_ctx *rs_ctx );
#endif
/**
* \brief Check that a point is a valid public key on this curve
*

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@ -101,9 +101,10 @@ void mbedtls_ecp_set_max_ops( unsigned max_ops )
}
/*
* Restart context type for interrupted operations
* Restart sub-context for ecp_mul_comb()
*/
struct mbedtls_ecp_restart_mul {
struct mbedtls_ecp_restart_mul
{
mbedtls_ecp_point R; /* current intermediate result */
size_t i; /* current index in various loops, 0 outside */
mbedtls_ecp_point *T; /* table for precomputed points */
@ -119,7 +120,7 @@ struct mbedtls_ecp_restart_mul {
};
/*
* Init restart_mul context
* Init restart_mul sub-context
*/
static void ecp_restart_mul_init( mbedtls_ecp_restart_mul_ctx *ctx )
{
@ -127,7 +128,7 @@ static void ecp_restart_mul_init( mbedtls_ecp_restart_mul_ctx *ctx )
}
/*
* Free the components of a restart_mul context
* Free the components of a restart_mul sub-context
*/
static void ecp_restart_mul_free( mbedtls_ecp_restart_mul_ctx *ctx )
{
@ -147,6 +148,33 @@ static void ecp_restart_mul_free( mbedtls_ecp_restart_mul_ctx *ctx )
memset( ctx, 0, sizeof( mbedtls_ecp_restart_mul_ctx ) );
}
/*
* Restart context for ecp_muladd()
*/
struct mbedtls_ecp_restart_muladd
{
int state; /* dummy for now */
};
/*
* Init restart_muladd sub-context
*/
static void ecp_restart_muladd_init( mbedtls_ecp_restart_muladd_ctx *ctx )
{
memset( ctx, 0, sizeof( *ctx ) );
}
/*
* Free the components of a restart_muladd sub-context
*/
static void ecp_restart_muladd_free( mbedtls_ecp_restart_muladd_ctx *ctx )
{
if( ctx == NULL )
return;
memset( ctx, 0, sizeof( *ctx ) );
}
/*
* Initialize a restart context
*/
@ -1868,9 +1896,9 @@ cleanup:
if( ret != 0 )
mbedtls_ecp_point_free( R );
/* clear restart context when not in progress (done or error) */
/* clear our sub-context when not in progress (done or error) */
#if defined(MBEDTLS_ECP_EARLY_RETURN)
if( rs_ctx != NULL && rs_ctx->rsm != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) {
if( rs_ctx != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) {
ecp_restart_mul_free( rs_ctx->rsm );
mbedtls_free( rs_ctx->rsm );
rs_ctx->rsm = NULL;
@ -2248,12 +2276,17 @@ cleanup:
}
/*
* Linear combination
* Restartable linear combination
* NOT constant-time
*/
int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
#if !defined(MBEDTLS_ECP_EARLY_RETURN)
static
#endif
int mbedtls_ecp_muladd_restartable(
mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
const mbedtls_mpi *n, const mbedtls_ecp_point *Q )
const mbedtls_mpi *n, const mbedtls_ecp_point *Q,
mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
mbedtls_ecp_point mP;
@ -2261,9 +2294,29 @@ int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
char is_grp_capable = 0;
#endif
#if !defined(MBEDTLS_ECP_EARLY_RETURN)
(void) rs_ctx;
#endif
if( ecp_get_type( grp ) != ECP_TYPE_SHORT_WEIERSTRASS )
return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
#if defined(MBEDTLS_ECP_EARLY_RETURN)
/* reset ops count for this call if top-level */
if( rs_ctx != NULL && rs_ctx->depth++ == 0 )
rs_ctx->ops_done = 0;
/* set up our own sub-context if needed */
if( ecp_max_ops != 0 && rs_ctx != NULL && rs_ctx->ma == NULL )
{
rs_ctx->ma = mbedtls_calloc( 1, sizeof( mbedtls_ecp_restart_muladd_ctx ) );
if( rs_ctx->ma == NULL )
return( MBEDTLS_ERR_ECP_ALLOC_FAILED );
ecp_restart_muladd_init( rs_ctx->ma );
}
#endif /* MBEDTLS_ECP_EARLY_RETURN */
mbedtls_ecp_point_init( &mP );
MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, &mP, m, P ) );
@ -2290,9 +2343,32 @@ cleanup:
#endif /* MBEDTLS_ECP_INTERNAL_ALT */
mbedtls_ecp_point_free( &mP );
#if defined(MBEDTLS_ECP_EARLY_RETURN)
/* clear our sub-context when not in progress (done or error) */
if( rs_ctx != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) {
ecp_restart_muladd_free( rs_ctx->ma );
mbedtls_free( rs_ctx->ma );
rs_ctx->ma = NULL;
}
if( rs_ctx != NULL )
rs_ctx->depth--;
#endif /* MBEDTLS_ECP_EARLY_RETURN */
return( ret );
}
/*
* Linear combination
* NOT constant-time
*/
int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
const mbedtls_mpi *n, const mbedtls_ecp_point *Q )
{
return( mbedtls_ecp_muladd_restartable( grp, R, m, P, n, Q, NULL ) );
}
#if defined(ECP_MONTGOMERY)
/*

View File

@ -345,18 +345,22 @@ ecp_test_vect:MBEDTLS_ECP_DP_SECP256K1:"923C6D4756CD940CD1E13A359F6E0F0698791938
ECP selftest
ecp_selftest:
ECP early return secp256r1 restart disabled
ECP early return mul secp256r1 restart disabled
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":0:0:0
ECP early return secp256r1 restart max_ops=1
ECP early return mul secp256r1 restart max_ops=1
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":1:1:5000
ECP early return secp256r1 restart max_ops=10000
ECP early return mul secp256r1 restart max_ops=10000
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":10000:0:0
ECP early return secp256r1 restart max_ops=250
ECP early return mul secp256r1 restart max_ops=250
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":250:2:32
ECP early return muladd secp256r1 restart disabled
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
ecp_muladd_restart:MBEDTLS_ECP_DP_SECP256R1:"CB28E0999B9C7715FD0A80D8E47A77079716CBBF917DD72E97566EA1C066957C":"2B57C0235FB7489768D058FF4911C20FDBE71E3699D91339AFBB903EE17255DC":"C3875E57C85038A0D60370A87505200DC8317C8C534948BEA6559C7C18E6D4CE":"3B4E49C4FDBFC006FF993C81A50EAE221149076D6EC09DDD9FB3B787F85B6483":"2442A5CC0ECD015FA3CA31DC8E2BBC70BF42D60CBCA20085E0822CB04235E970":"6FC98BD7E50211A4A27102FA3549DF79EBCB4BF246B80945CDDFE7D509BBFD7D":0:0:0

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@ -145,6 +145,77 @@ exit:
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ECP_EARLY_RETURN */
void ecp_muladd_restart( int id, char *xR_str, char *yR_str,
char *u1_str, char *u2_str,
char *xQ_str, char *yQ_str,
int max_ops, int min_restarts, int max_restarts )
{
/*
* Compute R = u1 * G + u2 * Q
* (test vectors mostly taken from ECDSA intermediate results)
*
* See comments at the top of ecp_test_vect_restart()
*/
mbedtls_ecp_restart_ctx ctx;
mbedtls_ecp_group grp;
mbedtls_ecp_point R, Q;
mbedtls_mpi u1, u2, xR, yR;
int cnt_restarts;
int ret;
mbedtls_ecp_restart_init( &ctx );
mbedtls_ecp_group_init( &grp );
mbedtls_ecp_point_init( &R );
mbedtls_ecp_point_init( &Q );
mbedtls_mpi_init( &u1 ); mbedtls_mpi_init( &u2 );
mbedtls_mpi_init( &xR ); mbedtls_mpi_init( &yR );
TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &u1, 16, u1_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &u2, 16, u2_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &xR, 16, xR_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &yR, 16, yR_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &Q.X, 16, xQ_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_read_string( &Q.Y, 16, yQ_str ) == 0 );
TEST_ASSERT( mbedtls_mpi_lset( &Q.Z, 1 ) == 0 );
mbedtls_ecp_set_max_ops( (unsigned) max_ops );
cnt_restarts = 0;
do {
ret = mbedtls_ecp_muladd_restartable( &grp, &R,
&u1, &grp.G, &u2, &Q, &ctx );
TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
cnt_restarts++;
}
while( ret != 0 );
TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.X, &xR ) == 0 );
TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.Y, &yR ) == 0 );
TEST_ASSERT( cnt_restarts >= min_restarts );
TEST_ASSERT( cnt_restarts <= max_restarts );
/* Do we leak memory when aborting? */
ret = mbedtls_ecp_muladd_restartable( &grp, &R,
&u1, &grp.G, &u2, &Q, &ctx );
TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
exit:
mbedtls_ecp_restart_free( &ctx );
mbedtls_ecp_group_free( &grp );
mbedtls_ecp_point_free( &R );
mbedtls_ecp_point_free( &Q );
mbedtls_mpi_free( &u1 ); mbedtls_mpi_free( &u2 );
mbedtls_mpi_free( &xR ); mbedtls_mpi_free( &yR );
}
/* END_CASE */
/* BEGIN_CASE */
void ecp_test_vect( int id, char *dA_str, char *xA_str, char *yA_str,
char *dB_str, char *xB_str, char *yB_str, char *xZ_str,