diff options
Diffstat (limited to 'thirdparty/mbedtls/library/ecp.c')
| -rw-r--r-- | thirdparty/mbedtls/library/ecp.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/thirdparty/mbedtls/library/ecp.c b/thirdparty/mbedtls/library/ecp.c index db36191b9b..725e176df2 100644 --- a/thirdparty/mbedtls/library/ecp.c +++ b/thirdparty/mbedtls/library/ecp.c @@ -1938,6 +1938,20 @@ static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp, final_norm: #endif + /* + * Knowledge of the jacobian coordinates may leak the last few bits of the + * scalar [1], and since our MPI implementation isn't constant-flow, + * inversion (used for coordinate normalization) may leak the full value + * of its input via side-channels [2]. + * + * [1] https://eprint.iacr.org/2003/191 + * [2] https://eprint.iacr.org/2020/055 + * + * Avoid the leak by randomizing coordinates before we normalize them. + */ + if( f_rng != 0 ) + MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, RR, f_rng, p_rng ) ); + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV ); MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) ); @@ -2308,6 +2322,20 @@ static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->Z, &RP.Z, b ) ); } + /* + * Knowledge of the projective coordinates may leak the last few bits of the + * scalar [1], and since our MPI implementation isn't constant-flow, + * inversion (used for coordinate normalization) may leak the full value + * of its input via side-channels [2]. + * + * [1] https://eprint.iacr.org/2003/191 + * [2] https://eprint.iacr.org/2020/055 + * + * Avoid the leak by randomizing coordinates before we normalize them. + */ + if( f_rng != NULL ) + MBEDTLS_MPI_CHK( ecp_randomize_mxz( grp, R, f_rng, p_rng ) ); + MBEDTLS_MPI_CHK( ecp_normalize_mxz( grp, R ) ); cleanup: @@ -2724,6 +2752,7 @@ int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp, { /* SEC1 3.2.1: Generate d such that 1 <= n < N */ int count = 0; + unsigned cmp = 0; /* * Match the procedure given in RFC 6979 (deterministic ECDSA): @@ -2748,9 +2777,14 @@ int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp, */ if( ++count > 30 ) return( MBEDTLS_ERR_ECP_RANDOM_FAILED ); + + ret = mbedtls_mpi_lt_mpi_ct( d, &grp->N, &cmp ); + if( ret != 0 ) + { + goto cleanup; + } } - while( mbedtls_mpi_cmp_int( d, 1 ) < 0 || - mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 ); + while( mbedtls_mpi_cmp_int( d, 1 ) < 0 || cmp != 1 ); } #endif /* ECP_SHORTWEIERSTRASS */ |