#include "mbedtls/hmac_drbg.h"
#endif
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc calloc
+#define mbedtls_free free
+#endif
+
+#include "mbedtls/platform_util.h"
+
+/* Parameter validation macros based on platform_util.h */
+#define ECDSA_VALIDATE_RET( cond ) \
+ MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA )
+#define ECDSA_VALIDATE( cond ) \
+ MBEDTLS_INTERNAL_VALIDATE( cond )
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+
+/*
+ * Sub-context for ecdsa_verify()
+ */
+struct mbedtls_ecdsa_restart_ver
+{
+ mbedtls_mpi u1, u2; /* intermediate values */
+ enum { /* what to do next? */
+ ecdsa_ver_init = 0, /* getting started */
+ ecdsa_ver_muladd, /* muladd step */
+ } state;
+};
+
+/*
+ * Init verify restart sub-context
+ */
+static void ecdsa_restart_ver_init( mbedtls_ecdsa_restart_ver_ctx *ctx )
+{
+ mbedtls_mpi_init( &ctx->u1 );
+ mbedtls_mpi_init( &ctx->u2 );
+ ctx->state = ecdsa_ver_init;
+}
+
+/*
+ * Free the components of a verify restart sub-context
+ */
+static void ecdsa_restart_ver_free( mbedtls_ecdsa_restart_ver_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ mbedtls_mpi_free( &ctx->u1 );
+ mbedtls_mpi_free( &ctx->u2 );
+
+ ecdsa_restart_ver_init( ctx );
+}
+
+/*
+ * Sub-context for ecdsa_sign()
+ */
+struct mbedtls_ecdsa_restart_sig
+{
+ int sign_tries;
+ int key_tries;
+ mbedtls_mpi k; /* per-signature random */
+ mbedtls_mpi r; /* r value */
+ enum { /* what to do next? */
+ ecdsa_sig_init = 0, /* getting started */
+ ecdsa_sig_mul, /* doing ecp_mul() */
+ ecdsa_sig_modn, /* mod N computations */
+ } state;
+};
+
+/*
+ * Init verify sign sub-context
+ */
+static void ecdsa_restart_sig_init( mbedtls_ecdsa_restart_sig_ctx *ctx )
+{
+ ctx->sign_tries = 0;
+ ctx->key_tries = 0;
+ mbedtls_mpi_init( &ctx->k );
+ mbedtls_mpi_init( &ctx->r );
+ ctx->state = ecdsa_sig_init;
+}
+
+/*
+ * Free the components of a sign restart sub-context
+ */
+static void ecdsa_restart_sig_free( mbedtls_ecdsa_restart_sig_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ mbedtls_mpi_free( &ctx->k );
+ mbedtls_mpi_free( &ctx->r );
+}
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+/*
+ * Sub-context for ecdsa_sign_det()
+ */
+struct mbedtls_ecdsa_restart_det
+{
+ mbedtls_hmac_drbg_context rng_ctx; /* DRBG state */
+ enum { /* what to do next? */
+ ecdsa_det_init = 0, /* getting started */
+ ecdsa_det_sign, /* make signature */
+ } state;
+};
+
+/*
+ * Init verify sign_det sub-context
+ */
+static void ecdsa_restart_det_init( mbedtls_ecdsa_restart_det_ctx *ctx )
+{
+ mbedtls_hmac_drbg_init( &ctx->rng_ctx );
+ ctx->state = ecdsa_det_init;
+}
+
+/*
+ * Free the components of a sign_det restart sub-context
+ */
+static void ecdsa_restart_det_free( mbedtls_ecdsa_restart_det_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ mbedtls_hmac_drbg_free( &ctx->rng_ctx );
+
+ ecdsa_restart_det_init( ctx );
+}
+#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
+
+#define ECDSA_RS_ECP ( rs_ctx == NULL ? NULL : &rs_ctx->ecp )
+
+/* Utility macro for checking and updating ops budget */
+#define ECDSA_BUDGET( ops ) \
+ MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, ECDSA_RS_ECP, ops ) );
+
+/* Call this when entering a function that needs its own sub-context */
+#define ECDSA_RS_ENTER( SUB ) do { \
+ /* reset ops count for this call if top-level */ \
+ if( rs_ctx != NULL && rs_ctx->ecp.depth++ == 0 ) \
+ rs_ctx->ecp.ops_done = 0; \
+ \
+ /* set up our own sub-context if needed */ \
+ if( mbedtls_ecp_restart_is_enabled() && \
+ rs_ctx != NULL && rs_ctx->SUB == NULL ) \
+ { \
+ rs_ctx->SUB = mbedtls_calloc( 1, sizeof( *rs_ctx->SUB ) ); \
+ if( rs_ctx->SUB == NULL ) \
+ return( MBEDTLS_ERR_ECP_ALLOC_FAILED ); \
+ \
+ ecdsa_restart_## SUB ##_init( rs_ctx->SUB ); \
+ } \
+} while( 0 )
+
+/* Call this when leaving a function that needs its own sub-context */
+#define ECDSA_RS_LEAVE( SUB ) do { \
+ /* clear our sub-context when not in progress (done or error) */ \
+ if( rs_ctx != NULL && rs_ctx->SUB != NULL && \
+ ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) \
+ { \
+ ecdsa_restart_## SUB ##_free( rs_ctx->SUB ); \
+ mbedtls_free( rs_ctx->SUB ); \
+ rs_ctx->SUB = NULL; \
+ } \
+ \
+ if( rs_ctx != NULL ) \
+ rs_ctx->ecp.depth--; \
+} while( 0 )
+
+#else /* MBEDTLS_ECP_RESTARTABLE */
+
+#define ECDSA_RS_ECP NULL
+
+#define ECDSA_BUDGET( ops ) /* no-op; for compatibility */
+
+#define ECDSA_RS_ENTER( SUB ) (void) rs_ctx
+#define ECDSA_RS_LEAVE( SUB ) (void) rs_ctx
+
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC) || \
+ !defined(MBEDTLS_ECDSA_SIGN_ALT) || \
+ !defined(MBEDTLS_ECDSA_VERIFY_ALT)
/*
* Derive a suitable integer for group grp from a buffer of length len
* SEC1 4.1.3 step 5 aka SEC1 4.1.4 step 3
cleanup:
return( ret );
}
+#endif /* ECDSA_DETERMINISTIC || !ECDSA_SIGN_ALT || !ECDSA_VERIFY_ALT */
#if !defined(MBEDTLS_ECDSA_SIGN_ALT)
/*
* Compute ECDSA signature of a hashed message (SEC1 4.1.3)
* Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message)
*/
-static int ecdsa_sign_internal( mbedtls_ecp_group *grp, mbedtls_mpi *r,
- mbedtls_mpi *s, const mbedtls_mpi *d,
- const unsigned char *buf, size_t blen,
- int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng,
- int (*f_rng_blind)(void *, unsigned char *,
- size_t),
- void *p_rng_blind )
+static int ecdsa_sign_restartable( mbedtls_ecp_group *grp,
+ mbedtls_mpi *r, mbedtls_mpi *s,
+ const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+ int (*f_rng_blind)(void *, unsigned char *, size_t),
+ void *p_rng_blind,
+ mbedtls_ecdsa_restart_ctx *rs_ctx )
{
- int ret, key_tries, sign_tries, blind_tries;
+ int ret, key_tries, sign_tries;
+ int *p_sign_tries = &sign_tries, *p_key_tries = &key_tries;
mbedtls_ecp_point R;
mbedtls_mpi k, e, t;
+ mbedtls_mpi *pk = &k, *pr = r;
/* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
if( grp->N.p == NULL )
mbedtls_ecp_point_init( &R );
mbedtls_mpi_init( &k ); mbedtls_mpi_init( &e ); mbedtls_mpi_init( &t );
- sign_tries = 0;
+ ECDSA_RS_ENTER( sig );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->sig != NULL )
+ {
+ /* redirect to our context */
+ p_sign_tries = &rs_ctx->sig->sign_tries;
+ p_key_tries = &rs_ctx->sig->key_tries;
+ pk = &rs_ctx->sig->k;
+ pr = &rs_ctx->sig->r;
+
+ /* jump to current step */
+ if( rs_ctx->sig->state == ecdsa_sig_mul )
+ goto mul;
+ if( rs_ctx->sig->state == ecdsa_sig_modn )
+ goto modn;
+ }
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
+ *p_sign_tries = 0;
do
{
+ if( (*p_sign_tries)++ > 10 )
+ {
+ ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
+ goto cleanup;
+ }
+
/*
* Steps 1-3: generate a suitable ephemeral keypair
* and set r = xR mod n
*/
- key_tries = 0;
+ *p_key_tries = 0;
do
{
- MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, &k, f_rng, p_rng ) );
-
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &R, &k, &grp->G,
- f_rng_blind, p_rng_blind ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( r, &R.X, &grp->N ) );
-
- if( key_tries++ > 10 )
+ if( (*p_key_tries)++ > 10 )
{
ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
goto cleanup;
}
+
+ MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, pk, f_rng, p_rng ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->sig != NULL )
+ rs_ctx->sig->state = ecdsa_sig_mul;
+
+mul:
+#endif
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &R, pk, &grp->G,
+ f_rng_blind,
+ p_rng_blind,
+ ECDSA_RS_ECP ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pr, &R.X, &grp->N ) );
}
- while( mbedtls_mpi_cmp_int( r, 0 ) == 0 );
+ while( mbedtls_mpi_cmp_int( pr, 0 ) == 0 );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->sig != NULL )
+ rs_ctx->sig->state = ecdsa_sig_modn;
+
+modn:
+#endif
+ /*
+ * Accounting for everything up to the end of the loop
+ * (step 6, but checking now avoids saving e and t)
+ */
+ ECDSA_BUDGET( MBEDTLS_ECP_OPS_INV + 4 );
/*
* Step 5: derive MPI from hashed message
/*
* Generate a random value to blind inv_mod in next step,
* avoiding a potential timing leak.
- *
- * This loop does the same job as mbedtls_ecp_gen_privkey() and it is
- * replaced by a call to it in the mainline. This change is not
- * necessary to backport the fix separating the blinding and ephemeral
- * key generating RNGs, therefore the original code is kept.
*/
- blind_tries = 0;
- do
- {
- size_t n_size = ( grp->nbits + 7 ) / 8;
- MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &t, n_size, f_rng_blind,
- p_rng_blind ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &t, 8 * n_size - grp->nbits ) );
-
- if( ++blind_tries > 30 )
- return( MBEDTLS_ERR_ECP_RANDOM_FAILED );
- }
- while( mbedtls_mpi_cmp_int( &t, 1 ) < 0 ||
- mbedtls_mpi_cmp_mpi( &t, &grp->N ) >= 0 );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, &t, f_rng_blind,
+ p_rng_blind ) );
/*
* Step 6: compute s = (e + r * d) / k = t (e + rd) / (kt) mod n
*/
- MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( s, r, d ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( s, pr, d ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &e, &e, s ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &e, &e, &t ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &k, &k, &t ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &k, &k, &grp->N ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( s, &k, &grp->N ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pk, pk, &t ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pk, pk, &grp->N ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( s, pk, &grp->N ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( s, s, &e ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( s, s, &grp->N ) );
-
- if( sign_tries++ > 10 )
- {
- ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
- goto cleanup;
- }
}
while( mbedtls_mpi_cmp_int( s, 0 ) == 0 );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->sig != NULL )
+ mbedtls_mpi_copy( r, pr );
+#endif
+
cleanup:
mbedtls_ecp_point_free( &R );
mbedtls_mpi_free( &k ); mbedtls_mpi_free( &e ); mbedtls_mpi_free( &t );
+ ECDSA_RS_LEAVE( sig );
+
return( ret );
}
+/*
+ * Compute ECDSA signature of a hashed message
+ */
int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
- const mbedtls_mpi *d, const unsigned char *buf,
- size_t blen,
- int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng )
+ const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
+ ECDSA_VALIDATE_RET( grp != NULL );
+ ECDSA_VALIDATE_RET( r != NULL );
+ ECDSA_VALIDATE_RET( s != NULL );
+ ECDSA_VALIDATE_RET( d != NULL );
+ ECDSA_VALIDATE_RET( f_rng != NULL );
+ ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
+
/* Use the same RNG for both blinding and ephemeral key generation */
- return( ecdsa_sign_internal( grp, r, s, d, buf, blen, f_rng, p_rng,
- f_rng, p_rng ) );
+ return( ecdsa_sign_restartable( grp, r, s, d, buf, blen,
+ f_rng, p_rng, f_rng, p_rng, NULL ) );
}
-#endif /* MBEDTLS_ECDSA_SIGN_ALT */
+#endif /* !MBEDTLS_ECDSA_SIGN_ALT */
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
-static int ecdsa_sign_det_internal( mbedtls_ecp_group *grp, mbedtls_mpi *r,
- mbedtls_mpi *s, const mbedtls_mpi *d,
- const unsigned char *buf, size_t blen,
- mbedtls_md_type_t md_alg,
- int (*f_rng_blind)(void *, unsigned char *,
- size_t),
- void *p_rng_blind )
+/*
+ * Deterministic signature wrapper
+ */
+static int ecdsa_sign_det_restartable( mbedtls_ecp_group *grp,
+ mbedtls_mpi *r, mbedtls_mpi *s,
+ const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
+ mbedtls_md_type_t md_alg,
+ int (*f_rng_blind)(void *, unsigned char *, size_t),
+ void *p_rng_blind,
+ mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_hmac_drbg_context rng_ctx;
+ mbedtls_hmac_drbg_context *p_rng = &rng_ctx;
unsigned char data[2 * MBEDTLS_ECP_MAX_BYTES];
size_t grp_len = ( grp->nbits + 7 ) / 8;
const mbedtls_md_info_t *md_info;
mbedtls_mpi h;
- /* Variables for deterministic blinding fallback */
- const char* blind_label = "BLINDING CONTEXT";
- mbedtls_hmac_drbg_context rng_ctx_blind;
if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
mbedtls_mpi_init( &h );
mbedtls_hmac_drbg_init( &rng_ctx );
- mbedtls_hmac_drbg_init( &rng_ctx_blind );
+
+ ECDSA_RS_ENTER( det );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->det != NULL )
+ {
+ /* redirect to our context */
+ p_rng = &rs_ctx->det->rng_ctx;
+
+ /* jump to current step */
+ if( rs_ctx->det->state == ecdsa_det_sign )
+ goto sign;
+ }
+#endif /* MBEDTLS_ECP_RESTARTABLE */
/* Use private key and message hash (reduced) to initialize HMAC_DRBG */
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( d, data, grp_len ) );
MBEDTLS_MPI_CHK( derive_mpi( grp, &h, buf, blen ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, data + grp_len, grp_len ) );
- mbedtls_hmac_drbg_seed_buf( &rng_ctx, md_info, data, 2 * grp_len );
+ mbedtls_hmac_drbg_seed_buf( p_rng, md_info, data, 2 * grp_len );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->det != NULL )
+ rs_ctx->det->state = ecdsa_det_sign;
+sign:
+#endif
+#if defined(MBEDTLS_ECDSA_SIGN_ALT)
+ ret = mbedtls_ecdsa_sign( grp, r, s, d, buf, blen,
+ mbedtls_hmac_drbg_random, p_rng );
+#else
if( f_rng_blind != NULL )
- ret = ecdsa_sign_internal( grp, r, s, d, buf, blen,
- mbedtls_hmac_drbg_random, &rng_ctx,
- f_rng_blind, p_rng_blind );
+ ret = ecdsa_sign_restartable( grp, r, s, d, buf, blen,
+ mbedtls_hmac_drbg_random, p_rng,
+ f_rng_blind, p_rng_blind, rs_ctx );
else
{
+ mbedtls_hmac_drbg_context *p_rng_blind_det;
+
+#if !defined(MBEDTLS_ECP_RESTARTABLE)
/*
* To avoid reusing rng_ctx and risking incorrect behavior we seed a
* second HMAC-DRBG with the same seed. We also apply a label to avoid
* reusing the bits of the ephemeral key for blinding and eliminate the
* risk that they leak this way.
*/
+ const char* blind_label = "BLINDING CONTEXT";
+ mbedtls_hmac_drbg_context rng_ctx_blind;
+
+ mbedtls_hmac_drbg_init( &rng_ctx_blind );
+ p_rng_blind_det = &rng_ctx_blind;
- mbedtls_hmac_drbg_seed_buf( &rng_ctx_blind, md_info,
+ mbedtls_hmac_drbg_seed_buf( p_rng_blind_det, md_info,
data, 2 * grp_len );
- ret = mbedtls_hmac_drbg_update_ret( &rng_ctx_blind,
+ ret = mbedtls_hmac_drbg_update_ret( p_rng_blind_det,
(const unsigned char*) blind_label,
strlen( blind_label ) );
if( ret != 0 )
+ {
+ mbedtls_hmac_drbg_free( &rng_ctx_blind );
goto cleanup;
+ }
+#else
+ /*
+ * In the case of restartable computations we would either need to store
+ * the second RNG in the restart context too or set it up at every
+ * restart. The first option would penalize the correct application of
+ * the function and the second would defeat the purpose of the
+ * restartable feature.
+ *
+ * Therefore in this case we reuse the original RNG. This comes with the
+ * price that the resulting signature might not be a valid deterministic
+ * ECDSA signature with a very low probability (same magnitude as
+ * successfully guessing the private key). However even then it is still
+ * a valid ECDSA signature.
+ */
+ p_rng_blind_det = p_rng;
+#endif /* MBEDTLS_ECP_RESTARTABLE */
/*
* Since the output of the RNGs is always the same for the same key and
* won't be a valid value for f_rng_blind anymore. Therefore it should
* be checked by the caller and this branch and check can be removed.
*/
- ret = ecdsa_sign_internal( grp, r, s, d, buf, blen,
- mbedtls_hmac_drbg_random, &rng_ctx,
- mbedtls_hmac_drbg_random, &rng_ctx_blind );
+ ret = ecdsa_sign_restartable( grp, r, s, d, buf, blen,
+ mbedtls_hmac_drbg_random, p_rng,
+ mbedtls_hmac_drbg_random, p_rng_blind_det,
+ rs_ctx );
+#if !defined(MBEDTLS_ECP_RESTARTABLE)
+ mbedtls_hmac_drbg_free( &rng_ctx_blind );
+#endif
}
+#endif /* MBEDTLS_ECDSA_SIGN_ALT */
cleanup:
mbedtls_hmac_drbg_free( &rng_ctx );
- mbedtls_hmac_drbg_free( &rng_ctx_blind );
mbedtls_mpi_free( &h );
+ ECDSA_RS_LEAVE( det );
+
return( ret );
}
const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg )
{
- return( ecdsa_sign_det_internal( grp, r, s, d, buf, blen, md_alg,
- NULL, NULL ) );
+ ECDSA_VALIDATE_RET( grp != NULL );
+ ECDSA_VALIDATE_RET( r != NULL );
+ ECDSA_VALIDATE_RET( s != NULL );
+ ECDSA_VALIDATE_RET( d != NULL );
+ ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
+
+ return( ecdsa_sign_det_restartable( grp, r, s, d, buf, blen, md_alg,
+ NULL, NULL, NULL ) );
}
int mbedtls_ecdsa_sign_det_ext( mbedtls_ecp_group *grp, mbedtls_mpi *r,
size_t),
void *p_rng_blind )
{
- return( ecdsa_sign_det_internal( grp, r, s, d, buf, blen, md_alg,
- f_rng_blind, p_rng_blind ) );
+ ECDSA_VALIDATE_RET( grp != NULL );
+ ECDSA_VALIDATE_RET( r != NULL );
+ ECDSA_VALIDATE_RET( s != NULL );
+ ECDSA_VALIDATE_RET( d != NULL );
+ ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
+ ECDSA_VALIDATE_RET( f_rng_blind != NULL );
+
+ return( ecdsa_sign_det_restartable( grp, r, s, d, buf, blen, md_alg,
+ f_rng_blind, p_rng_blind, NULL ) );
}
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
* Verify ECDSA signature of hashed message (SEC1 4.1.4)
* Obviously, compared to SEC1 4.1.3, we skip step 2 (hash message)
*/
-int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
- const unsigned char *buf, size_t blen,
- const mbedtls_ecp_point *Q, const mbedtls_mpi *r, const mbedtls_mpi *s)
+static int ecdsa_verify_restartable( mbedtls_ecp_group *grp,
+ const unsigned char *buf, size_t blen,
+ const mbedtls_ecp_point *Q,
+ const mbedtls_mpi *r, const mbedtls_mpi *s,
+ mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_mpi e, s_inv, u1, u2;
mbedtls_ecp_point R;
+ mbedtls_mpi *pu1 = &u1, *pu2 = &u2;
mbedtls_ecp_point_init( &R );
- mbedtls_mpi_init( &e ); mbedtls_mpi_init( &s_inv ); mbedtls_mpi_init( &u1 ); mbedtls_mpi_init( &u2 );
+ mbedtls_mpi_init( &e ); mbedtls_mpi_init( &s_inv );
+ mbedtls_mpi_init( &u1 ); mbedtls_mpi_init( &u2 );
/* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
if( grp->N.p == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+ ECDSA_RS_ENTER( ver );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ver != NULL )
+ {
+ /* redirect to our context */
+ pu1 = &rs_ctx->ver->u1;
+ pu2 = &rs_ctx->ver->u2;
+
+ /* jump to current step */
+ if( rs_ctx->ver->state == ecdsa_ver_muladd )
+ goto muladd;
+ }
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
/*
* Step 1: make sure r and s are in range 1..n-1
*/
goto cleanup;
}
- /*
- * Additional precaution: make sure Q is valid
- */
- MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, Q ) );
-
/*
* Step 3: derive MPI from hashed message
*/
/*
* Step 4: u1 = e / s mod n, u2 = r / s mod n
*/
+ ECDSA_BUDGET( MBEDTLS_ECP_OPS_CHK + MBEDTLS_ECP_OPS_INV + 2 );
+
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &s_inv, s, &grp->N ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &u1, &e, &s_inv ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &u1, &u1, &grp->N ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pu1, &e, &s_inv ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pu1, pu1, &grp->N ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &u2, r, &s_inv ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &u2, &u2, &grp->N ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pu2, r, &s_inv ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pu2, pu2, &grp->N ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ver != NULL )
+ rs_ctx->ver->state = ecdsa_ver_muladd;
+
+muladd:
+#endif
/*
* Step 5: R = u1 G + u2 Q
- *
- * Since we're not using any secret data, no need to pass a RNG to
- * mbedtls_ecp_mul() for countermesures.
*/
- MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( grp, &R, &u1, &grp->G, &u2, Q ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_muladd_restartable( grp,
+ &R, pu1, &grp->G, pu2, Q, ECDSA_RS_ECP ) );
if( mbedtls_ecp_is_zero( &R ) )
{
cleanup:
mbedtls_ecp_point_free( &R );
- mbedtls_mpi_free( &e ); mbedtls_mpi_free( &s_inv ); mbedtls_mpi_free( &u1 ); mbedtls_mpi_free( &u2 );
+ mbedtls_mpi_free( &e ); mbedtls_mpi_free( &s_inv );
+ mbedtls_mpi_free( &u1 ); mbedtls_mpi_free( &u2 );
+
+ ECDSA_RS_LEAVE( ver );
return( ret );
}
-#endif /* MBEDTLS_ECDSA_VERIFY_ALT */
+
+/*
+ * Verify ECDSA signature of hashed message
+ */
+int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
+ const unsigned char *buf, size_t blen,
+ const mbedtls_ecp_point *Q,
+ const mbedtls_mpi *r,
+ const mbedtls_mpi *s)
+{
+ ECDSA_VALIDATE_RET( grp != NULL );
+ ECDSA_VALIDATE_RET( Q != NULL );
+ ECDSA_VALIDATE_RET( r != NULL );
+ ECDSA_VALIDATE_RET( s != NULL );
+ ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
+
+ return( ecdsa_verify_restartable( grp, buf, blen, Q, r, s, NULL ) );
+}
+#endif /* !MBEDTLS_ECDSA_VERIFY_ALT */
/*
* Convert a signature (given by context) to ASN.1
/*
* Compute and write signature
*/
-int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg,
+int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
+ mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng )
+ void *p_rng,
+ mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_mpi r, s;
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( hash != NULL );
+ ECDSA_VALIDATE_RET( sig != NULL );
+ ECDSA_VALIDATE_RET( slen != NULL );
mbedtls_mpi_init( &r );
mbedtls_mpi_init( &s );
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
- MBEDTLS_MPI_CHK( ecdsa_sign_det_internal( &ctx->grp, &r, &s, &ctx->d,
- hash, hlen, md_alg,
- f_rng, p_rng ) );
+ MBEDTLS_MPI_CHK( ecdsa_sign_det_restartable( &ctx->grp, &r, &s, &ctx->d,
+ hash, hlen, md_alg, f_rng,
+ p_rng, rs_ctx ) );
#else
(void) md_alg;
+#if defined(MBEDTLS_ECDSA_SIGN_ALT)
+ (void) rs_ctx;
+
MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, f_rng, p_rng ) );
+#else
+ /* Use the same RNG for both blinding and ephemeral key generation */
+ MBEDTLS_MPI_CHK( ecdsa_sign_restartable( &ctx->grp, &r, &s, &ctx->d,
+ hash, hlen, f_rng, p_rng, f_rng,
+ p_rng, rs_ctx ) );
+#endif /* MBEDTLS_ECDSA_SIGN_ALT */
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) );
return( ret );
}
-#if ! defined(MBEDTLS_DEPRECATED_REMOVED) && \
+/*
+ * Compute and write signature
+ */
+int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hlen,
+ unsigned char *sig, size_t *slen,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng )
+{
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( hash != NULL );
+ ECDSA_VALIDATE_RET( sig != NULL );
+ ECDSA_VALIDATE_RET( slen != NULL );
+ return( mbedtls_ecdsa_write_signature_restartable(
+ ctx, md_alg, hash, hlen, sig, slen, f_rng, p_rng, NULL ) );
+}
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED) && \
defined(MBEDTLS_ECDSA_DETERMINISTIC)
int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
mbedtls_md_type_t md_alg )
{
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( hash != NULL );
+ ECDSA_VALIDATE_RET( sig != NULL );
+ ECDSA_VALIDATE_RET( slen != NULL );
return( mbedtls_ecdsa_write_signature( ctx, md_alg, hash, hlen, sig, slen,
NULL, NULL ) );
}
int mbedtls_ecdsa_read_signature( mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen )
+{
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( hash != NULL );
+ ECDSA_VALIDATE_RET( sig != NULL );
+ return( mbedtls_ecdsa_read_signature_restartable(
+ ctx, hash, hlen, sig, slen, NULL ) );
+}
+
+/*
+ * Restartable read and check signature
+ */
+int mbedtls_ecdsa_read_signature_restartable( mbedtls_ecdsa_context *ctx,
+ const unsigned char *hash, size_t hlen,
+ const unsigned char *sig, size_t slen,
+ mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
unsigned char *p = (unsigned char *) sig;
const unsigned char *end = sig + slen;
size_t len;
mbedtls_mpi r, s;
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( hash != NULL );
+ ECDSA_VALIDATE_RET( sig != NULL );
mbedtls_mpi_init( &r );
mbedtls_mpi_init( &s );
ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
goto cleanup;
}
+#if defined(MBEDTLS_ECDSA_VERIFY_ALT)
+ (void) rs_ctx;
if( ( ret = mbedtls_ecdsa_verify( &ctx->grp, hash, hlen,
- &ctx->Q, &r, &s ) ) != 0 )
+ &ctx->Q, &r, &s ) ) != 0 )
+ goto cleanup;
+#else
+ if( ( ret = ecdsa_verify_restartable( &ctx->grp, hash, hlen,
+ &ctx->Q, &r, &s, rs_ctx ) ) != 0 )
goto cleanup;
+#endif /* MBEDTLS_ECDSA_VERIFY_ALT */
/* At this point we know that the buffer starts with a valid signature.
* Return 0 if the buffer just contains the signature, and a specific
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
int ret = 0;
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( f_rng != NULL );
+
ret = mbedtls_ecp_group_load( &ctx->grp, gid );
if( ret != 0 )
return( ret );
return( mbedtls_ecp_gen_keypair( &ctx->grp, &ctx->d,
&ctx->Q, f_rng, p_rng ) );
}
-#endif /* MBEDTLS_ECDSA_GENKEY_ALT */
+#endif /* !MBEDTLS_ECDSA_GENKEY_ALT */
/*
* Set context from an mbedtls_ecp_keypair
int mbedtls_ecdsa_from_keypair( mbedtls_ecdsa_context *ctx, const mbedtls_ecp_keypair *key )
{
int ret;
+ ECDSA_VALIDATE_RET( ctx != NULL );
+ ECDSA_VALIDATE_RET( key != NULL );
if( ( ret = mbedtls_ecp_group_copy( &ctx->grp, &key->grp ) ) != 0 ||
( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 ||
*/
void mbedtls_ecdsa_init( mbedtls_ecdsa_context *ctx )
{
+ ECDSA_VALIDATE( ctx != NULL );
+
mbedtls_ecp_keypair_init( ctx );
}
*/
void mbedtls_ecdsa_free( mbedtls_ecdsa_context *ctx )
{
+ if( ctx == NULL )
+ return;
+
mbedtls_ecp_keypair_free( ctx );
}
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+/*
+ * Initialize a restart context
+ */
+void mbedtls_ecdsa_restart_init( mbedtls_ecdsa_restart_ctx *ctx )
+{
+ ECDSA_VALIDATE( ctx != NULL );
+
+ mbedtls_ecp_restart_init( &ctx->ecp );
+
+ ctx->ver = NULL;
+ ctx->sig = NULL;
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+ ctx->det = NULL;
+#endif
+}
+
+/*
+ * Free the components of a restart context
+ */
+void mbedtls_ecdsa_restart_free( mbedtls_ecdsa_restart_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ mbedtls_ecp_restart_free( &ctx->ecp );
+
+ ecdsa_restart_ver_free( ctx->ver );
+ mbedtls_free( ctx->ver );
+ ctx->ver = NULL;
+
+ ecdsa_restart_sig_free( ctx->sig );
+ mbedtls_free( ctx->sig );
+ ctx->sig = NULL;
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+ ecdsa_restart_det_free( ctx->det );
+ mbedtls_free( ctx->det );
+ ctx->det = NULL;
+#endif
+}
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
#endif /* MBEDTLS_ECDSA_C */
projects / reactos.git / blobdiff