mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
0d748ad58e
This change fixes Cosmopolitan so it has fewer opinions about compiler warnings. The whole repository had to be cleaned up to be buildable in -Werror -Wall mode. This lets us benefit from things like strict const checking. Some actual bugs might have been caught too.
105 lines
4.7 KiB
C
105 lines
4.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:4;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright The Mbed TLS Contributors │
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│ │
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│ Licensed under the Apache License, Version 2.0 (the "License"); │
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│ you may not use this file except in compliance with the License. │
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│ You may obtain a copy of the License at │
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│ │
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│ http://www.apache.org/licenses/LICENSE-2.0 │
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│ │
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│ Unless required by applicable law or agreed to in writing, software │
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│ distributed under the License is distributed on an "AS IS" BASIS, │
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│ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. │
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│ See the License for the specific language governing permissions and │
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│ limitations under the License. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "third_party/mbedtls/ecp.h"
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#include "third_party/mbedtls/math.h"
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/* clang-format off */
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static void mbedtls_mpi_shift_l_mod_p256( const mbedtls_ecp_group *G,
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mbedtls_mpi *X )
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{
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bool c;
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MBEDTLS_ASSERT( G->P.n == 4 );
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MBEDTLS_ASSERT( mbedtls_mpi_bitlen( X ) <= 256 );
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MBEDTLS_ASSERT( mbedtls_mpi_bitlen( &G->P ) <= 256 );
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X->p[4] = X->p[3] >> 63;
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X->p[3] = X->p[3] << 1 | X->p[2] >> 63;
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X->p[2] = X->p[2] << 1 | X->p[1] >> 63;
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X->p[1] = X->p[1] << 1 | X->p[0] >> 63;
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X->p[0] = X->p[0] << 1;
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if( (X->p[4] ||
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X->p[3] > G->P.p[3] ||
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((X->p[3] == G->P.p[3] &&
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X->p[2] > G->P.p[2]) ||
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((X->p[2] == G->P.p[2] &&
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X->p[0] > G->P.p[0]) ||
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(X->p[0] == G->P.p[0])))) )
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{
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SBB(X->p[0], X->p[0], G->P.p[0], 0, c);
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SBB(X->p[1], X->p[1], G->P.p[1], c, c);
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SBB(X->p[2], X->p[2], G->P.p[2], c, c);
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SBB(X->p[3], X->p[3], G->P.p[3], c, c);
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SBB(X->p[4], X->p[4], 0, c, c);
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}
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}
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static void mbedtls_mpi_shift_l_mod_p384( const mbedtls_ecp_group *G,
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mbedtls_mpi *X )
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{
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bool c;
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MBEDTLS_ASSERT( G->P.n == 6 );
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MBEDTLS_ASSERT( mbedtls_mpi_bitlen( X ) <= 384 );
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MBEDTLS_ASSERT( mbedtls_mpi_bitlen( &G->P ) <= 384 );
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X->p[6] = X->p[5] >> 63;
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X->p[5] = X->p[5] << 1 | X->p[4] >> 63;
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X->p[4] = X->p[4] << 1 | X->p[3] >> 63;
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X->p[3] = X->p[3] << 1 | X->p[2] >> 63;
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X->p[2] = X->p[2] << 1 | X->p[1] >> 63;
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X->p[1] = X->p[1] << 1 | X->p[0] >> 63;
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X->p[0] = X->p[0] << 1;
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if( (X->p[6] ||
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X->p[5] > G->P.p[5] ||
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((X->p[5] == G->P.p[5] &&
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X->p[4] > G->P.p[4]) ||
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((X->p[4] == G->P.p[4] &&
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X->p[3] > G->P.p[3]) ||
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((X->p[3] == G->P.p[3] &&
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X->p[2] > G->P.p[2]) ||
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((X->p[2] == G->P.p[2] &&
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X->p[0] > G->P.p[0]) ||
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(X->p[0] == G->P.p[0])))))) )
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{
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SBB(X->p[0], X->p[0], G->P.p[0], 0, c);
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SBB(X->p[1], X->p[1], G->P.p[1], c, c);
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SBB(X->p[2], X->p[2], G->P.p[2], c, c);
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SBB(X->p[3], X->p[3], G->P.p[3], c, c);
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SBB(X->p[4], X->p[4], G->P.p[4], c, c);
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SBB(X->p[5], X->p[5], G->P.p[5], c, c);
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SBB(X->p[6], X->p[6], 0, c, c);
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}
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}
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int mbedtls_mpi_shift_l_mod( const mbedtls_ecp_group *G, mbedtls_mpi *X )
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{
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int ret = 0;
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MBEDTLS_ASSERT( mbedtls_mpi_cmp_int( X, 0 ) >= 0 );
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MBEDTLS_ASSERT( mbedtls_mpi_cmp_mpi( X, &G->P ) < 0 );
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if( X->n == 8 )
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mbedtls_mpi_shift_l_mod_p256( G, X );
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else if( X->n == 12 )
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mbedtls_mpi_shift_l_mod_p384( G, X );
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else
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{
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MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( X, 1 ) );
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if( mbedtls_mpi_cmp_mpi( X, &G->P ) >= 0 )
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MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( X, X, &G->P ) );
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}
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MBEDTLS_ASSERT( mbedtls_mpi_cmp_mpi( X, &G->P ) < 0 );
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MBEDTLS_ASSERT( mbedtls_mpi_cmp_int( X, 0 ) >= 0 );
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cleanup:
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return( ret );
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}
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