diff options
Diffstat (limited to 'thirdparty/mbedtls/library/ecp.c')
| -rw-r--r-- | thirdparty/mbedtls/library/ecp.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/ecp.c b/thirdparty/mbedtls/library/ecp.c index 040c20bd38..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: |