diff options
Diffstat (limited to 'thirdparty/mbedtls/library/bignum.c')
| -rw-r--r-- | thirdparty/mbedtls/library/bignum.c | 2457 | 
1 files changed, 2457 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/bignum.c b/thirdparty/mbedtls/library/bignum.c new file mode 100644 index 0000000000..d27c130bcb --- /dev/null +++ b/thirdparty/mbedtls/library/bignum.c @@ -0,0 +1,2457 @@ +/* + *  Multi-precision integer library + * + *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved + *  SPDX-License-Identifier: Apache-2.0 + * + *  Licensed under the Apache License, Version 2.0 (the "License"); you may + *  not use this file except in compliance with the License. + *  You may obtain a copy of the License at + * + *  http://www.apache.org/licenses/LICENSE-2.0 + * + *  Unless required by applicable law or agreed to in writing, software + *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + *  See the License for the specific language governing permissions and + *  limitations under the License. + * + *  This file is part of mbed TLS (https://tls.mbed.org) + */ + +/* + *  The following sources were referenced in the design of this Multi-precision + *  Integer library: + * + *  [1] Handbook of Applied Cryptography - 1997 + *      Menezes, van Oorschot and Vanstone + * + *  [2] Multi-Precision Math + *      Tom St Denis + *      https://github.com/libtom/libtommath/blob/develop/tommath.pdf + * + *  [3] GNU Multi-Precision Arithmetic Library + *      https://gmplib.org/manual/index.html + * + */ + +#if !defined(MBEDTLS_CONFIG_FILE) +#include "mbedtls/config.h" +#else +#include MBEDTLS_CONFIG_FILE +#endif + +#if defined(MBEDTLS_BIGNUM_C) + +#include "mbedtls/bignum.h" +#include "mbedtls/bn_mul.h" + +#include <string.h> + +#if defined(MBEDTLS_PLATFORM_C) +#include "mbedtls/platform.h" +#else +#include <stdio.h> +#include <stdlib.h> +#define mbedtls_printf     printf +#define mbedtls_calloc    calloc +#define mbedtls_free       free +#endif + +/* Implementation that should never be optimized out by the compiler */ +static void mbedtls_mpi_zeroize( mbedtls_mpi_uint *v, size_t n ) { +    volatile mbedtls_mpi_uint *p = v; while( n-- ) *p++ = 0; +} + +/* Implementation that should never be optimized out by the compiler */ +static void mbedtls_zeroize( void *v, size_t n ) { +    volatile unsigned char *p = v; while( n-- ) *p++ = 0; +} + +#define ciL    (sizeof(mbedtls_mpi_uint))         /* chars in limb  */ +#define biL    (ciL << 3)               /* bits  in limb  */ +#define biH    (ciL << 2)               /* half limb size */ + +#define MPI_SIZE_T_MAX  ( (size_t) -1 ) /* SIZE_T_MAX is not standard */ + +/* + * Convert between bits/chars and number of limbs + * Divide first in order to avoid potential overflows + */ +#define BITS_TO_LIMBS(i)  ( (i) / biL + ( (i) % biL != 0 ) ) +#define CHARS_TO_LIMBS(i) ( (i) / ciL + ( (i) % ciL != 0 ) ) + +/* + * Initialize one MPI + */ +void mbedtls_mpi_init( mbedtls_mpi *X ) +{ +    if( X == NULL ) +        return; + +    X->s = 1; +    X->n = 0; +    X->p = NULL; +} + +/* + * Unallocate one MPI + */ +void mbedtls_mpi_free( mbedtls_mpi *X ) +{ +    if( X == NULL ) +        return; + +    if( X->p != NULL ) +    { +        mbedtls_mpi_zeroize( X->p, X->n ); +        mbedtls_free( X->p ); +    } + +    X->s = 1; +    X->n = 0; +    X->p = NULL; +} + +/* + * Enlarge to the specified number of limbs + */ +int mbedtls_mpi_grow( mbedtls_mpi *X, size_t nblimbs ) +{ +    mbedtls_mpi_uint *p; + +    if( nblimbs > MBEDTLS_MPI_MAX_LIMBS ) +        return( MBEDTLS_ERR_MPI_ALLOC_FAILED ); + +    if( X->n < nblimbs ) +    { +        if( ( p = (mbedtls_mpi_uint*)mbedtls_calloc( nblimbs, ciL ) ) == NULL ) +            return( MBEDTLS_ERR_MPI_ALLOC_FAILED ); + +        if( X->p != NULL ) +        { +            memcpy( p, X->p, X->n * ciL ); +            mbedtls_mpi_zeroize( X->p, X->n ); +            mbedtls_free( X->p ); +        } + +        X->n = nblimbs; +        X->p = p; +    } + +    return( 0 ); +} + +/* + * Resize down as much as possible, + * while keeping at least the specified number of limbs + */ +int mbedtls_mpi_shrink( mbedtls_mpi *X, size_t nblimbs ) +{ +    mbedtls_mpi_uint *p; +    size_t i; + +    /* Actually resize up in this case */ +    if( X->n <= nblimbs ) +        return( mbedtls_mpi_grow( X, nblimbs ) ); + +    for( i = X->n - 1; i > 0; i-- ) +        if( X->p[i] != 0 ) +            break; +    i++; + +    if( i < nblimbs ) +        i = nblimbs; + +    if( ( p = (mbedtls_mpi_uint*)mbedtls_calloc( i, ciL ) ) == NULL ) +        return( MBEDTLS_ERR_MPI_ALLOC_FAILED ); + +    if( X->p != NULL ) +    { +        memcpy( p, X->p, i * ciL ); +        mbedtls_mpi_zeroize( X->p, X->n ); +        mbedtls_free( X->p ); +    } + +    X->n = i; +    X->p = p; + +    return( 0 ); +} + +/* + * Copy the contents of Y into X + */ +int mbedtls_mpi_copy( mbedtls_mpi *X, const mbedtls_mpi *Y ) +{ +    int ret; +    size_t i; + +    if( X == Y ) +        return( 0 ); + +    if( Y->p == NULL ) +    { +        mbedtls_mpi_free( X ); +        return( 0 ); +    } + +    for( i = Y->n - 1; i > 0; i-- ) +        if( Y->p[i] != 0 ) +            break; +    i++; + +    X->s = Y->s; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, i ) ); + +    memset( X->p, 0, X->n * ciL ); +    memcpy( X->p, Y->p, i * ciL ); + +cleanup: + +    return( ret ); +} + +/* + * Swap the contents of X and Y + */ +void mbedtls_mpi_swap( mbedtls_mpi *X, mbedtls_mpi *Y ) +{ +    mbedtls_mpi T; + +    memcpy( &T,  X, sizeof( mbedtls_mpi ) ); +    memcpy(  X,  Y, sizeof( mbedtls_mpi ) ); +    memcpy(  Y, &T, sizeof( mbedtls_mpi ) ); +} + +/* + * Conditionally assign X = Y, without leaking information + * about whether the assignment was made or not. + * (Leaking information about the respective sizes of X and Y is ok however.) + */ +int mbedtls_mpi_safe_cond_assign( mbedtls_mpi *X, const mbedtls_mpi *Y, unsigned char assign ) +{ +    int ret = 0; +    size_t i; + +    /* make sure assign is 0 or 1 in a time-constant manner */ +    assign = (assign | (unsigned char)-assign) >> 7; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, Y->n ) ); + +    X->s = X->s * ( 1 - assign ) + Y->s * assign; + +    for( i = 0; i < Y->n; i++ ) +        X->p[i] = X->p[i] * ( 1 - assign ) + Y->p[i] * assign; + +    for( ; i < X->n; i++ ) +        X->p[i] *= ( 1 - assign ); + +cleanup: +    return( ret ); +} + +/* + * Conditionally swap X and Y, without leaking information + * about whether the swap was made or not. + * Here it is not ok to simply swap the pointers, which whould lead to + * different memory access patterns when X and Y are used afterwards. + */ +int mbedtls_mpi_safe_cond_swap( mbedtls_mpi *X, mbedtls_mpi *Y, unsigned char swap ) +{ +    int ret, s; +    size_t i; +    mbedtls_mpi_uint tmp; + +    if( X == Y ) +        return( 0 ); + +    /* make sure swap is 0 or 1 in a time-constant manner */ +    swap = (swap | (unsigned char)-swap) >> 7; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, Y->n ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( Y, X->n ) ); + +    s = X->s; +    X->s = X->s * ( 1 - swap ) + Y->s * swap; +    Y->s = Y->s * ( 1 - swap ) +    s * swap; + + +    for( i = 0; i < X->n; i++ ) +    { +        tmp = X->p[i]; +        X->p[i] = X->p[i] * ( 1 - swap ) + Y->p[i] * swap; +        Y->p[i] = Y->p[i] * ( 1 - swap ) +     tmp * swap; +    } + +cleanup: +    return( ret ); +} + +/* + * Set value from integer + */ +int mbedtls_mpi_lset( mbedtls_mpi *X, mbedtls_mpi_sint z ) +{ +    int ret; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, 1 ) ); +    memset( X->p, 0, X->n * ciL ); + +    X->p[0] = ( z < 0 ) ? -z : z; +    X->s    = ( z < 0 ) ? -1 : 1; + +cleanup: + +    return( ret ); +} + +/* + * Get a specific bit + */ +int mbedtls_mpi_get_bit( const mbedtls_mpi *X, size_t pos ) +{ +    if( X->n * biL <= pos ) +        return( 0 ); + +    return( ( X->p[pos / biL] >> ( pos % biL ) ) & 0x01 ); +} + +/* + * Set a bit to a specific value of 0 or 1 + */ +int mbedtls_mpi_set_bit( mbedtls_mpi *X, size_t pos, unsigned char val ) +{ +    int ret = 0; +    size_t off = pos / biL; +    size_t idx = pos % biL; + +    if( val != 0 && val != 1 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    if( X->n * biL <= pos ) +    { +        if( val == 0 ) +            return( 0 ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, off + 1 ) ); +    } + +    X->p[off] &= ~( (mbedtls_mpi_uint) 0x01 << idx ); +    X->p[off] |= (mbedtls_mpi_uint) val << idx; + +cleanup: + +    return( ret ); +} + +/* + * Return the number of less significant zero-bits + */ +size_t mbedtls_mpi_lsb( const mbedtls_mpi *X ) +{ +    size_t i, j, count = 0; + +    for( i = 0; i < X->n; i++ ) +        for( j = 0; j < biL; j++, count++ ) +            if( ( ( X->p[i] >> j ) & 1 ) != 0 ) +                return( count ); + +    return( 0 ); +} + +/* + * Count leading zero bits in a given integer + */ +static size_t mbedtls_clz( const mbedtls_mpi_uint x ) +{ +    size_t j; +    mbedtls_mpi_uint mask = (mbedtls_mpi_uint) 1 << (biL - 1); + +    for( j = 0; j < biL; j++ ) +    { +        if( x & mask ) break; + +        mask >>= 1; +    } + +    return j; +} + +/* + * Return the number of bits + */ +size_t mbedtls_mpi_bitlen( const mbedtls_mpi *X ) +{ +    size_t i, j; + +    if( X->n == 0 ) +        return( 0 ); + +    for( i = X->n - 1; i > 0; i-- ) +        if( X->p[i] != 0 ) +            break; + +    j = biL - mbedtls_clz( X->p[i] ); + +    return( ( i * biL ) + j ); +} + +/* + * Return the total size in bytes + */ +size_t mbedtls_mpi_size( const mbedtls_mpi *X ) +{ +    return( ( mbedtls_mpi_bitlen( X ) + 7 ) >> 3 ); +} + +/* + * Convert an ASCII character to digit value + */ +static int mpi_get_digit( mbedtls_mpi_uint *d, int radix, char c ) +{ +    *d = 255; + +    if( c >= 0x30 && c <= 0x39 ) *d = c - 0x30; +    if( c >= 0x41 && c <= 0x46 ) *d = c - 0x37; +    if( c >= 0x61 && c <= 0x66 ) *d = c - 0x57; + +    if( *d >= (mbedtls_mpi_uint) radix ) +        return( MBEDTLS_ERR_MPI_INVALID_CHARACTER ); + +    return( 0 ); +} + +/* + * Import from an ASCII string + */ +int mbedtls_mpi_read_string( mbedtls_mpi *X, int radix, const char *s ) +{ +    int ret; +    size_t i, j, slen, n; +    mbedtls_mpi_uint d; +    mbedtls_mpi T; + +    if( radix < 2 || radix > 16 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    mbedtls_mpi_init( &T ); + +    slen = strlen( s ); + +    if( radix == 16 ) +    { +        if( slen > MPI_SIZE_T_MAX >> 2 ) +            return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +        n = BITS_TO_LIMBS( slen << 2 ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, n ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_lset( X, 0 ) ); + +        for( i = slen, j = 0; i > 0; i--, j++ ) +        { +            if( i == 1 && s[i - 1] == '-' ) +            { +                X->s = -1; +                break; +            } + +            MBEDTLS_MPI_CHK( mpi_get_digit( &d, radix, s[i - 1] ) ); +            X->p[j / ( 2 * ciL )] |= d << ( ( j % ( 2 * ciL ) ) << 2 ); +        } +    } +    else +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_lset( X, 0 ) ); + +        for( i = 0; i < slen; i++ ) +        { +            if( i == 0 && s[i] == '-' ) +            { +                X->s = -1; +                continue; +            } + +            MBEDTLS_MPI_CHK( mpi_get_digit( &d, radix, s[i] ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &T, X, radix ) ); + +            if( X->s == 1 ) +            { +                MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( X, &T, d ) ); +            } +            else +            { +                MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( X, &T, d ) ); +            } +        } +    } + +cleanup: + +    mbedtls_mpi_free( &T ); + +    return( ret ); +} + +/* + * Helper to write the digits high-order first + */ +static int mpi_write_hlp( mbedtls_mpi *X, int radix, char **p ) +{ +    int ret; +    mbedtls_mpi_uint r; + +    if( radix < 2 || radix > 16 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_mod_int( &r, X, radix ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_div_int( X, NULL, X, radix ) ); + +    if( mbedtls_mpi_cmp_int( X, 0 ) != 0 ) +        MBEDTLS_MPI_CHK( mpi_write_hlp( X, radix, p ) ); + +    if( r < 10 ) +        *(*p)++ = (char)( r + 0x30 ); +    else +        *(*p)++ = (char)( r + 0x37 ); + +cleanup: + +    return( ret ); +} + +/* + * Export into an ASCII string + */ +int mbedtls_mpi_write_string( const mbedtls_mpi *X, int radix, +                              char *buf, size_t buflen, size_t *olen ) +{ +    int ret = 0; +    size_t n; +    char *p; +    mbedtls_mpi T; + +    if( radix < 2 || radix > 16 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    n = mbedtls_mpi_bitlen( X ); +    if( radix >=  4 ) n >>= 1; +    if( radix >= 16 ) n >>= 1; +    /* +     * Round up the buffer length to an even value to ensure that there is +     * enough room for hexadecimal values that can be represented in an odd +     * number of digits. +     */ +    n += 3 + ( ( n + 1 ) & 1 ); + +    if( buflen < n ) +    { +        *olen = n; +        return( MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL ); +    } + +    p = buf; +    mbedtls_mpi_init( &T ); + +    if( X->s == -1 ) +        *p++ = '-'; + +    if( radix == 16 ) +    { +        int c; +        size_t i, j, k; + +        for( i = X->n, k = 0; i > 0; i-- ) +        { +            for( j = ciL; j > 0; j-- ) +            { +                c = ( X->p[i - 1] >> ( ( j - 1 ) << 3) ) & 0xFF; + +                if( c == 0 && k == 0 && ( i + j ) != 2 ) +                    continue; + +                *(p++) = "0123456789ABCDEF" [c / 16]; +                *(p++) = "0123456789ABCDEF" [c % 16]; +                k = 1; +            } +        } +    } +    else +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &T, X ) ); + +        if( T.s == -1 ) +            T.s = 1; + +        MBEDTLS_MPI_CHK( mpi_write_hlp( &T, radix, &p ) ); +    } + +    *p++ = '\0'; +    *olen = p - buf; + +cleanup: + +    mbedtls_mpi_free( &T ); + +    return( ret ); +} + +#if defined(MBEDTLS_FS_IO) +/* + * Read X from an opened file + */ +int mbedtls_mpi_read_file( mbedtls_mpi *X, int radix, FILE *fin ) +{ +    mbedtls_mpi_uint d; +    size_t slen; +    char *p; +    /* +     * Buffer should have space for (short) label and decimal formatted MPI, +     * newline characters and '\0' +     */ +    char s[ MBEDTLS_MPI_RW_BUFFER_SIZE ]; + +    memset( s, 0, sizeof( s ) ); +    if( fgets( s, sizeof( s ) - 1, fin ) == NULL ) +        return( MBEDTLS_ERR_MPI_FILE_IO_ERROR ); + +    slen = strlen( s ); +    if( slen == sizeof( s ) - 2 ) +        return( MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL ); + +    if( slen > 0 && s[slen - 1] == '\n' ) { slen--; s[slen] = '\0'; } +    if( slen > 0 && s[slen - 1] == '\r' ) { slen--; s[slen] = '\0'; } + +    p = s + slen; +    while( p-- > s ) +        if( mpi_get_digit( &d, radix, *p ) != 0 ) +            break; + +    return( mbedtls_mpi_read_string( X, radix, p + 1 ) ); +} + +/* + * Write X into an opened file (or stdout if fout == NULL) + */ +int mbedtls_mpi_write_file( const char *p, const mbedtls_mpi *X, int radix, FILE *fout ) +{ +    int ret; +    size_t n, slen, plen; +    /* +     * Buffer should have space for (short) label and decimal formatted MPI, +     * newline characters and '\0' +     */ +    char s[ MBEDTLS_MPI_RW_BUFFER_SIZE ]; + +    memset( s, 0, sizeof( s ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_write_string( X, radix, s, sizeof( s ) - 2, &n ) ); + +    if( p == NULL ) p = ""; + +    plen = strlen( p ); +    slen = strlen( s ); +    s[slen++] = '\r'; +    s[slen++] = '\n'; + +    if( fout != NULL ) +    { +        if( fwrite( p, 1, plen, fout ) != plen || +            fwrite( s, 1, slen, fout ) != slen ) +            return( MBEDTLS_ERR_MPI_FILE_IO_ERROR ); +    } +    else +        mbedtls_printf( "%s%s", p, s ); + +cleanup: + +    return( ret ); +} +#endif /* MBEDTLS_FS_IO */ + +/* + * Import X from unsigned binary data, big endian + */ +int mbedtls_mpi_read_binary( mbedtls_mpi *X, const unsigned char *buf, size_t buflen ) +{ +    int ret; +    size_t i, j; +    size_t const limbs = CHARS_TO_LIMBS( buflen ); + +    /* Ensure that target MPI has exactly the necessary number of limbs */ +    if( X->n != limbs ) +    { +        mbedtls_mpi_free( X ); +        mbedtls_mpi_init( X ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, limbs ) ); +    } + +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( X, 0 ) ); + +    for( i = buflen, j = 0; i > 0; i--, j++ ) +        X->p[j / ciL] |= ((mbedtls_mpi_uint) buf[i - 1]) << ((j % ciL) << 3); + +cleanup: + +    return( ret ); +} + +/* + * Export X into unsigned binary data, big endian + */ +int mbedtls_mpi_write_binary( const mbedtls_mpi *X, unsigned char *buf, size_t buflen ) +{ +    size_t i, j, n; + +    n = mbedtls_mpi_size( X ); + +    if( buflen < n ) +        return( MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL ); + +    memset( buf, 0, buflen ); + +    for( i = buflen - 1, j = 0; n > 0; i--, j++, n-- ) +        buf[i] = (unsigned char)( X->p[j / ciL] >> ((j % ciL) << 3) ); + +    return( 0 ); +} + +/* + * Left-shift: X <<= count + */ +int mbedtls_mpi_shift_l( mbedtls_mpi *X, size_t count ) +{ +    int ret; +    size_t i, v0, t1; +    mbedtls_mpi_uint r0 = 0, r1; + +    v0 = count / (biL    ); +    t1 = count & (biL - 1); + +    i = mbedtls_mpi_bitlen( X ) + count; + +    if( X->n * biL < i ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, BITS_TO_LIMBS( i ) ) ); + +    ret = 0; + +    /* +     * shift by count / limb_size +     */ +    if( v0 > 0 ) +    { +        for( i = X->n; i > v0; i-- ) +            X->p[i - 1] = X->p[i - v0 - 1]; + +        for( ; i > 0; i-- ) +            X->p[i - 1] = 0; +    } + +    /* +     * shift by count % limb_size +     */ +    if( t1 > 0 ) +    { +        for( i = v0; i < X->n; i++ ) +        { +            r1 = X->p[i] >> (biL - t1); +            X->p[i] <<= t1; +            X->p[i] |= r0; +            r0 = r1; +        } +    } + +cleanup: + +    return( ret ); +} + +/* + * Right-shift: X >>= count + */ +int mbedtls_mpi_shift_r( mbedtls_mpi *X, size_t count ) +{ +    size_t i, v0, v1; +    mbedtls_mpi_uint r0 = 0, r1; + +    v0 = count /  biL; +    v1 = count & (biL - 1); + +    if( v0 > X->n || ( v0 == X->n && v1 > 0 ) ) +        return mbedtls_mpi_lset( X, 0 ); + +    /* +     * shift by count / limb_size +     */ +    if( v0 > 0 ) +    { +        for( i = 0; i < X->n - v0; i++ ) +            X->p[i] = X->p[i + v0]; + +        for( ; i < X->n; i++ ) +            X->p[i] = 0; +    } + +    /* +     * shift by count % limb_size +     */ +    if( v1 > 0 ) +    { +        for( i = X->n; i > 0; i-- ) +        { +            r1 = X->p[i - 1] << (biL - v1); +            X->p[i - 1] >>= v1; +            X->p[i - 1] |= r0; +            r0 = r1; +        } +    } + +    return( 0 ); +} + +/* + * Compare unsigned values + */ +int mbedtls_mpi_cmp_abs( const mbedtls_mpi *X, const mbedtls_mpi *Y ) +{ +    size_t i, j; + +    for( i = X->n; i > 0; i-- ) +        if( X->p[i - 1] != 0 ) +            break; + +    for( j = Y->n; j > 0; j-- ) +        if( Y->p[j - 1] != 0 ) +            break; + +    if( i == 0 && j == 0 ) +        return( 0 ); + +    if( i > j ) return(  1 ); +    if( j > i ) return( -1 ); + +    for( ; i > 0; i-- ) +    { +        if( X->p[i - 1] > Y->p[i - 1] ) return(  1 ); +        if( X->p[i - 1] < Y->p[i - 1] ) return( -1 ); +    } + +    return( 0 ); +} + +/* + * Compare signed values + */ +int mbedtls_mpi_cmp_mpi( const mbedtls_mpi *X, const mbedtls_mpi *Y ) +{ +    size_t i, j; + +    for( i = X->n; i > 0; i-- ) +        if( X->p[i - 1] != 0 ) +            break; + +    for( j = Y->n; j > 0; j-- ) +        if( Y->p[j - 1] != 0 ) +            break; + +    if( i == 0 && j == 0 ) +        return( 0 ); + +    if( i > j ) return(  X->s ); +    if( j > i ) return( -Y->s ); + +    if( X->s > 0 && Y->s < 0 ) return(  1 ); +    if( Y->s > 0 && X->s < 0 ) return( -1 ); + +    for( ; i > 0; i-- ) +    { +        if( X->p[i - 1] > Y->p[i - 1] ) return(  X->s ); +        if( X->p[i - 1] < Y->p[i - 1] ) return( -X->s ); +    } + +    return( 0 ); +} + +/* + * Compare signed values + */ +int mbedtls_mpi_cmp_int( const mbedtls_mpi *X, mbedtls_mpi_sint z ) +{ +    mbedtls_mpi Y; +    mbedtls_mpi_uint p[1]; + +    *p  = ( z < 0 ) ? -z : z; +    Y.s = ( z < 0 ) ? -1 : 1; +    Y.n = 1; +    Y.p = p; + +    return( mbedtls_mpi_cmp_mpi( X, &Y ) ); +} + +/* + * Unsigned addition: X = |A| + |B|  (HAC 14.7) + */ +int mbedtls_mpi_add_abs( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret; +    size_t i, j; +    mbedtls_mpi_uint *o, *p, c, tmp; + +    if( X == B ) +    { +        const mbedtls_mpi *T = A; A = X; B = T; +    } + +    if( X != A ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( X, A ) ); + +    /* +     * X should always be positive as a result of unsigned additions. +     */ +    X->s = 1; + +    for( j = B->n; j > 0; j-- ) +        if( B->p[j - 1] != 0 ) +            break; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, j ) ); + +    o = B->p; p = X->p; c = 0; + +    /* +     * tmp is used because it might happen that p == o +     */ +    for( i = 0; i < j; i++, o++, p++ ) +    { +        tmp= *o; +        *p +=  c; c  = ( *p <  c ); +        *p += tmp; c += ( *p < tmp ); +    } + +    while( c != 0 ) +    { +        if( i >= X->n ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, i + 1 ) ); +            p = X->p + i; +        } + +        *p += c; c = ( *p < c ); i++; p++; +    } + +cleanup: + +    return( ret ); +} + +/* + * Helper for mbedtls_mpi subtraction + */ +static void mpi_sub_hlp( size_t n, mbedtls_mpi_uint *s, mbedtls_mpi_uint *d ) +{ +    size_t i; +    mbedtls_mpi_uint c, z; + +    for( i = c = 0; i < n; i++, s++, d++ ) +    { +        z = ( *d <  c );     *d -=  c; +        c = ( *d < *s ) + z; *d -= *s; +    } + +    while( c != 0 ) +    { +        z = ( *d < c ); *d -= c; +        c = z; i++; d++; +    } +} + +/* + * Unsigned subtraction: X = |A| - |B|  (HAC 14.9) + */ +int mbedtls_mpi_sub_abs( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    mbedtls_mpi TB; +    int ret; +    size_t n; + +    if( mbedtls_mpi_cmp_abs( A, B ) < 0 ) +        return( MBEDTLS_ERR_MPI_NEGATIVE_VALUE ); + +    mbedtls_mpi_init( &TB ); + +    if( X == B ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TB, B ) ); +        B = &TB; +    } + +    if( X != A ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( X, A ) ); + +    /* +     * X should always be positive as a result of unsigned subtractions. +     */ +    X->s = 1; + +    ret = 0; + +    for( n = B->n; n > 0; n-- ) +        if( B->p[n - 1] != 0 ) +            break; + +    mpi_sub_hlp( n, B->p, X->p ); + +cleanup: + +    mbedtls_mpi_free( &TB ); + +    return( ret ); +} + +/* + * Signed addition: X = A + B + */ +int mbedtls_mpi_add_mpi( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret, s = A->s; + +    if( A->s * B->s < 0 ) +    { +        if( mbedtls_mpi_cmp_abs( A, B ) >= 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( X, A, B ) ); +            X->s =  s; +        } +        else +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( X, B, A ) ); +            X->s = -s; +        } +    } +    else +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_add_abs( X, A, B ) ); +        X->s = s; +    } + +cleanup: + +    return( ret ); +} + +/* + * Signed subtraction: X = A - B + */ +int mbedtls_mpi_sub_mpi( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret, s = A->s; + +    if( A->s * B->s > 0 ) +    { +        if( mbedtls_mpi_cmp_abs( A, B ) >= 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( X, A, B ) ); +            X->s =  s; +        } +        else +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( X, B, A ) ); +            X->s = -s; +        } +    } +    else +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_add_abs( X, A, B ) ); +        X->s = s; +    } + +cleanup: + +    return( ret ); +} + +/* + * Signed addition: X = A + b + */ +int mbedtls_mpi_add_int( mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_sint b ) +{ +    mbedtls_mpi _B; +    mbedtls_mpi_uint p[1]; + +    p[0] = ( b < 0 ) ? -b : b; +    _B.s = ( b < 0 ) ? -1 : 1; +    _B.n = 1; +    _B.p = p; + +    return( mbedtls_mpi_add_mpi( X, A, &_B ) ); +} + +/* + * Signed subtraction: X = A - b + */ +int mbedtls_mpi_sub_int( mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_sint b ) +{ +    mbedtls_mpi _B; +    mbedtls_mpi_uint p[1]; + +    p[0] = ( b < 0 ) ? -b : b; +    _B.s = ( b < 0 ) ? -1 : 1; +    _B.n = 1; +    _B.p = p; + +    return( mbedtls_mpi_sub_mpi( X, A, &_B ) ); +} + +/* + * Helper for mbedtls_mpi multiplication + */ +static +#if defined(__APPLE__) && defined(__arm__) +/* + * Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn) + * appears to need this to prevent bad ARM code generation at -O3. + */ +__attribute__ ((noinline)) +#endif +void mpi_mul_hlp( size_t i, mbedtls_mpi_uint *s, mbedtls_mpi_uint *d, mbedtls_mpi_uint b ) +{ +    mbedtls_mpi_uint c = 0, t = 0; + +#if defined(MULADDC_HUIT) +    for( ; i >= 8; i -= 8 ) +    { +        MULADDC_INIT +        MULADDC_HUIT +        MULADDC_STOP +    } + +    for( ; i > 0; i-- ) +    { +        MULADDC_INIT +        MULADDC_CORE +        MULADDC_STOP +    } +#else /* MULADDC_HUIT */ +    for( ; i >= 16; i -= 16 ) +    { +        MULADDC_INIT +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE + +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_STOP +    } + +    for( ; i >= 8; i -= 8 ) +    { +        MULADDC_INIT +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE + +        MULADDC_CORE   MULADDC_CORE +        MULADDC_CORE   MULADDC_CORE +        MULADDC_STOP +    } + +    for( ; i > 0; i-- ) +    { +        MULADDC_INIT +        MULADDC_CORE +        MULADDC_STOP +    } +#endif /* MULADDC_HUIT */ + +    t++; + +    do { +        *d += c; c = ( *d < c ); d++; +    } +    while( c != 0 ); +} + +/* + * Baseline multiplication: X = A * B  (HAC 14.12) + */ +int mbedtls_mpi_mul_mpi( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret; +    size_t i, j; +    mbedtls_mpi TA, TB; + +    mbedtls_mpi_init( &TA ); mbedtls_mpi_init( &TB ); + +    if( X == A ) { MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TA, A ) ); A = &TA; } +    if( X == B ) { MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TB, B ) ); B = &TB; } + +    for( i = A->n; i > 0; i-- ) +        if( A->p[i - 1] != 0 ) +            break; + +    for( j = B->n; j > 0; j-- ) +        if( B->p[j - 1] != 0 ) +            break; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, i + j ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( X, 0 ) ); + +    for( i++; j > 0; j-- ) +        mpi_mul_hlp( i - 1, A->p, X->p + j - 1, B->p[j - 1] ); + +    X->s = A->s * B->s; + +cleanup: + +    mbedtls_mpi_free( &TB ); mbedtls_mpi_free( &TA ); + +    return( ret ); +} + +/* + * Baseline multiplication: X = A * b + */ +int mbedtls_mpi_mul_int( mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_uint b ) +{ +    mbedtls_mpi _B; +    mbedtls_mpi_uint p[1]; + +    _B.s = 1; +    _B.n = 1; +    _B.p = p; +    p[0] = b; + +    return( mbedtls_mpi_mul_mpi( X, A, &_B ) ); +} + +/* + * Unsigned integer divide - double mbedtls_mpi_uint dividend, u1/u0, and + * mbedtls_mpi_uint divisor, d + */ +static mbedtls_mpi_uint mbedtls_int_div_int( mbedtls_mpi_uint u1, +            mbedtls_mpi_uint u0, mbedtls_mpi_uint d, mbedtls_mpi_uint *r ) +{ +#if defined(MBEDTLS_HAVE_UDBL) +    mbedtls_t_udbl dividend, quotient; +#else +    const mbedtls_mpi_uint radix = (mbedtls_mpi_uint) 1 << biH; +    const mbedtls_mpi_uint uint_halfword_mask = ( (mbedtls_mpi_uint) 1 << biH ) - 1; +    mbedtls_mpi_uint d0, d1, q0, q1, rAX, r0, quotient; +    mbedtls_mpi_uint u0_msw, u0_lsw; +    size_t s; +#endif + +    /* +     * Check for overflow +     */ +    if( 0 == d || u1 >= d ) +    { +        if (r != NULL) *r = ~0; + +        return ( ~0 ); +    } + +#if defined(MBEDTLS_HAVE_UDBL) +    dividend  = (mbedtls_t_udbl) u1 << biL; +    dividend |= (mbedtls_t_udbl) u0; +    quotient = dividend / d; +    if( quotient > ( (mbedtls_t_udbl) 1 << biL ) - 1 ) +        quotient = ( (mbedtls_t_udbl) 1 << biL ) - 1; + +    if( r != NULL ) +        *r = (mbedtls_mpi_uint)( dividend - (quotient * d ) ); + +    return (mbedtls_mpi_uint) quotient; +#else + +    /* +     * Algorithm D, Section 4.3.1 - The Art of Computer Programming +     *   Vol. 2 - Seminumerical Algorithms, Knuth +     */ + +    /* +     * Normalize the divisor, d, and dividend, u0, u1 +     */ +    s = mbedtls_clz( d ); +    d = d << s; + +    u1 = u1 << s; +    u1 |= ( u0 >> ( biL - s ) ) & ( -(mbedtls_mpi_sint)s >> ( biL - 1 ) ); +    u0 =  u0 << s; + +    d1 = d >> biH; +    d0 = d & uint_halfword_mask; + +    u0_msw = u0 >> biH; +    u0_lsw = u0 & uint_halfword_mask; + +    /* +     * Find the first quotient and remainder +     */ +    q1 = u1 / d1; +    r0 = u1 - d1 * q1; + +    while( q1 >= radix || ( q1 * d0 > radix * r0 + u0_msw ) ) +    { +        q1 -= 1; +        r0 += d1; + +        if ( r0 >= radix ) break; +    } + +    rAX = ( u1 * radix ) + ( u0_msw - q1 * d ); +    q0 = rAX / d1; +    r0 = rAX - q0 * d1; + +    while( q0 >= radix || ( q0 * d0 > radix * r0 + u0_lsw ) ) +    { +        q0 -= 1; +        r0 += d1; + +        if ( r0 >= radix ) break; +    } + +    if (r != NULL) +        *r = ( rAX * radix + u0_lsw - q0 * d ) >> s; + +    quotient = q1 * radix + q0; + +    return quotient; +#endif +} + +/* + * Division by mbedtls_mpi: A = Q * B + R  (HAC 14.20) + */ +int mbedtls_mpi_div_mpi( mbedtls_mpi *Q, mbedtls_mpi *R, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret; +    size_t i, n, t, k; +    mbedtls_mpi X, Y, Z, T1, T2; + +    if( mbedtls_mpi_cmp_int( B, 0 ) == 0 ) +        return( MBEDTLS_ERR_MPI_DIVISION_BY_ZERO ); + +    mbedtls_mpi_init( &X ); mbedtls_mpi_init( &Y ); mbedtls_mpi_init( &Z ); +    mbedtls_mpi_init( &T1 ); mbedtls_mpi_init( &T2 ); + +    if( mbedtls_mpi_cmp_abs( A, B ) < 0 ) +    { +        if( Q != NULL ) MBEDTLS_MPI_CHK( mbedtls_mpi_lset( Q, 0 ) ); +        if( R != NULL ) MBEDTLS_MPI_CHK( mbedtls_mpi_copy( R, A ) ); +        return( 0 ); +    } + +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &X, A ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &Y, B ) ); +    X.s = Y.s = 1; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &Z, A->n + 2 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &Z,  0 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &T1, 2 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &T2, 3 ) ); + +    k = mbedtls_mpi_bitlen( &Y ) % biL; +    if( k < biL - 1 ) +    { +        k = biL - 1 - k; +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &X, k ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &Y, k ) ); +    } +    else k = 0; + +    n = X.n - 1; +    t = Y.n - 1; +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &Y, biL * ( n - t ) ) ); + +    while( mbedtls_mpi_cmp_mpi( &X, &Y ) >= 0 ) +    { +        Z.p[n - t]++; +        MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &X, &X, &Y ) ); +    } +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &Y, biL * ( n - t ) ) ); + +    for( i = n; i > t ; i-- ) +    { +        if( X.p[i] >= Y.p[t] ) +            Z.p[i - t - 1] = ~0; +        else +        { +            Z.p[i - t - 1] = mbedtls_int_div_int( X.p[i], X.p[i - 1], +                                                            Y.p[t], NULL); +        } + +        Z.p[i - t - 1]++; +        do +        { +            Z.p[i - t - 1]--; + +            MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &T1, 0 ) ); +            T1.p[0] = ( t < 1 ) ? 0 : Y.p[t - 1]; +            T1.p[1] = Y.p[t]; +            MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &T1, &T1, Z.p[i - t - 1] ) ); + +            MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &T2, 0 ) ); +            T2.p[0] = ( i < 2 ) ? 0 : X.p[i - 2]; +            T2.p[1] = ( i < 1 ) ? 0 : X.p[i - 1]; +            T2.p[2] = X.p[i]; +        } +        while( mbedtls_mpi_cmp_mpi( &T1, &T2 ) > 0 ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &T1, &Y, Z.p[i - t - 1] ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &T1,  biL * ( i - t - 1 ) ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &X, &X, &T1 ) ); + +        if( mbedtls_mpi_cmp_int( &X, 0 ) < 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &T1, &Y ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &T1, biL * ( i - t - 1 ) ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &X, &X, &T1 ) ); +            Z.p[i - t - 1]--; +        } +    } + +    if( Q != NULL ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( Q, &Z ) ); +        Q->s = A->s * B->s; +    } + +    if( R != NULL ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &X, k ) ); +        X.s = A->s; +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( R, &X ) ); + +        if( mbedtls_mpi_cmp_int( R, 0 ) == 0 ) +            R->s = 1; +    } + +cleanup: + +    mbedtls_mpi_free( &X ); mbedtls_mpi_free( &Y ); mbedtls_mpi_free( &Z ); +    mbedtls_mpi_free( &T1 ); mbedtls_mpi_free( &T2 ); + +    return( ret ); +} + +/* + * Division by int: A = Q * b + R + */ +int mbedtls_mpi_div_int( mbedtls_mpi *Q, mbedtls_mpi *R, const mbedtls_mpi *A, mbedtls_mpi_sint b ) +{ +    mbedtls_mpi _B; +    mbedtls_mpi_uint p[1]; + +    p[0] = ( b < 0 ) ? -b : b; +    _B.s = ( b < 0 ) ? -1 : 1; +    _B.n = 1; +    _B.p = p; + +    return( mbedtls_mpi_div_mpi( Q, R, A, &_B ) ); +} + +/* + * Modulo: R = A mod B + */ +int mbedtls_mpi_mod_mpi( mbedtls_mpi *R, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret; + +    if( mbedtls_mpi_cmp_int( B, 0 ) < 0 ) +        return( MBEDTLS_ERR_MPI_NEGATIVE_VALUE ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( NULL, R, A, B ) ); + +    while( mbedtls_mpi_cmp_int( R, 0 ) < 0 ) +      MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( R, R, B ) ); + +    while( mbedtls_mpi_cmp_mpi( R, B ) >= 0 ) +      MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( R, R, B ) ); + +cleanup: + +    return( ret ); +} + +/* + * Modulo: r = A mod b + */ +int mbedtls_mpi_mod_int( mbedtls_mpi_uint *r, const mbedtls_mpi *A, mbedtls_mpi_sint b ) +{ +    size_t i; +    mbedtls_mpi_uint x, y, z; + +    if( b == 0 ) +        return( MBEDTLS_ERR_MPI_DIVISION_BY_ZERO ); + +    if( b < 0 ) +        return( MBEDTLS_ERR_MPI_NEGATIVE_VALUE ); + +    /* +     * handle trivial cases +     */ +    if( b == 1 ) +    { +        *r = 0; +        return( 0 ); +    } + +    if( b == 2 ) +    { +        *r = A->p[0] & 1; +        return( 0 ); +    } + +    /* +     * general case +     */ +    for( i = A->n, y = 0; i > 0; i-- ) +    { +        x  = A->p[i - 1]; +        y  = ( y << biH ) | ( x >> biH ); +        z  = y / b; +        y -= z * b; + +        x <<= biH; +        y  = ( y << biH ) | ( x >> biH ); +        z  = y / b; +        y -= z * b; +    } + +    /* +     * If A is negative, then the current y represents a negative value. +     * Flipping it to the positive side. +     */ +    if( A->s < 0 && y != 0 ) +        y = b - y; + +    *r = y; + +    return( 0 ); +} + +/* + * Fast Montgomery initialization (thanks to Tom St Denis) + */ +static void mpi_montg_init( mbedtls_mpi_uint *mm, const mbedtls_mpi *N ) +{ +    mbedtls_mpi_uint x, m0 = N->p[0]; +    unsigned int i; + +    x  = m0; +    x += ( ( m0 + 2 ) & 4 ) << 1; + +    for( i = biL; i >= 8; i /= 2 ) +        x *= ( 2 - ( m0 * x ) ); + +    *mm = ~x + 1; +} + +/* + * Montgomery multiplication: A = A * B * R^-1 mod N  (HAC 14.36) + */ +static int mpi_montmul( mbedtls_mpi *A, const mbedtls_mpi *B, const mbedtls_mpi *N, mbedtls_mpi_uint mm, +                         const mbedtls_mpi *T ) +{ +    size_t i, n, m; +    mbedtls_mpi_uint u0, u1, *d; + +    if( T->n < N->n + 1 || T->p == NULL ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    memset( T->p, 0, T->n * ciL ); + +    d = T->p; +    n = N->n; +    m = ( B->n < n ) ? B->n : n; + +    for( i = 0; i < n; i++ ) +    { +        /* +         * T = (T + u0*B + u1*N) / 2^biL +         */ +        u0 = A->p[i]; +        u1 = ( d[0] + u0 * B->p[0] ) * mm; + +        mpi_mul_hlp( m, B->p, d, u0 ); +        mpi_mul_hlp( n, N->p, d, u1 ); + +        *d++ = u0; d[n + 1] = 0; +    } + +    memcpy( A->p, d, ( n + 1 ) * ciL ); + +    if( mbedtls_mpi_cmp_abs( A, N ) >= 0 ) +        mpi_sub_hlp( n, N->p, A->p ); +    else +        /* prevent timing attacks */ +        mpi_sub_hlp( n, A->p, T->p ); + +    return( 0 ); +} + +/* + * Montgomery reduction: A = A * R^-1 mod N + */ +static int mpi_montred( mbedtls_mpi *A, const mbedtls_mpi *N, mbedtls_mpi_uint mm, const mbedtls_mpi *T ) +{ +    mbedtls_mpi_uint z = 1; +    mbedtls_mpi U; + +    U.n = U.s = (int) z; +    U.p = &z; + +    return( mpi_montmul( A, &U, N, mm, T ) ); +} + +/* + * Sliding-window exponentiation: X = A^E mod N  (HAC 14.85) + */ +int mbedtls_mpi_exp_mod( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *E, const mbedtls_mpi *N, mbedtls_mpi *_RR ) +{ +    int ret; +    size_t wbits, wsize, one = 1; +    size_t i, j, nblimbs; +    size_t bufsize, nbits; +    mbedtls_mpi_uint ei, mm, state; +    mbedtls_mpi RR, T, W[ 2 << MBEDTLS_MPI_WINDOW_SIZE ], Apos; +    int neg; + +    if( mbedtls_mpi_cmp_int( N, 0 ) < 0 || ( N->p[0] & 1 ) == 0 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    if( mbedtls_mpi_cmp_int( E, 0 ) < 0 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    /* +     * Init temps and window size +     */ +    mpi_montg_init( &mm, N ); +    mbedtls_mpi_init( &RR ); mbedtls_mpi_init( &T ); +    mbedtls_mpi_init( &Apos ); +    memset( W, 0, sizeof( W ) ); + +    i = mbedtls_mpi_bitlen( E ); + +    wsize = ( i > 671 ) ? 6 : ( i > 239 ) ? 5 : +            ( i >  79 ) ? 4 : ( i >  23 ) ? 3 : 1; + +    if( wsize > MBEDTLS_MPI_WINDOW_SIZE ) +        wsize = MBEDTLS_MPI_WINDOW_SIZE; + +    j = N->n + 1; +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, j ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &W[1],  j ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &T, j * 2 ) ); + +    /* +     * Compensate for negative A (and correct at the end) +     */ +    neg = ( A->s == -1 ); +    if( neg ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &Apos, A ) ); +        Apos.s = 1; +        A = &Apos; +    } + +    /* +     * If 1st call, pre-compute R^2 mod N +     */ +    if( _RR == NULL || _RR->p == NULL ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &RR, 1 ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &RR, N->n * 2 * biL ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &RR, &RR, N ) ); + +        if( _RR != NULL ) +            memcpy( _RR, &RR, sizeof( mbedtls_mpi ) ); +    } +    else +        memcpy( &RR, _RR, sizeof( mbedtls_mpi ) ); + +    /* +     * W[1] = A * R^2 * R^-1 mod N = A * R mod N +     */ +    if( mbedtls_mpi_cmp_mpi( A, N ) >= 0 ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &W[1], A, N ) ); +    else +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &W[1], A ) ); + +    MBEDTLS_MPI_CHK( mpi_montmul( &W[1], &RR, N, mm, &T ) ); + +    /* +     * X = R^2 * R^-1 mod N = R mod N +     */ +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( X, &RR ) ); +    MBEDTLS_MPI_CHK( mpi_montred( X, N, mm, &T ) ); + +    if( wsize > 1 ) +    { +        /* +         * W[1 << (wsize - 1)] = W[1] ^ (wsize - 1) +         */ +        j =  one << ( wsize - 1 ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &W[j], N->n + 1 ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &W[j], &W[1]    ) ); + +        for( i = 0; i < wsize - 1; i++ ) +            MBEDTLS_MPI_CHK( mpi_montmul( &W[j], &W[j], N, mm, &T ) ); + +        /* +         * W[i] = W[i - 1] * W[1] +         */ +        for( i = j + 1; i < ( one << wsize ); i++ ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_grow( &W[i], N->n + 1 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &W[i], &W[i - 1] ) ); + +            MBEDTLS_MPI_CHK( mpi_montmul( &W[i], &W[1], N, mm, &T ) ); +        } +    } + +    nblimbs = E->n; +    bufsize = 0; +    nbits   = 0; +    wbits   = 0; +    state   = 0; + +    while( 1 ) +    { +        if( bufsize == 0 ) +        { +            if( nblimbs == 0 ) +                break; + +            nblimbs--; + +            bufsize = sizeof( mbedtls_mpi_uint ) << 3; +        } + +        bufsize--; + +        ei = (E->p[nblimbs] >> bufsize) & 1; + +        /* +         * skip leading 0s +         */ +        if( ei == 0 && state == 0 ) +            continue; + +        if( ei == 0 && state == 1 ) +        { +            /* +             * out of window, square X +             */ +            MBEDTLS_MPI_CHK( mpi_montmul( X, X, N, mm, &T ) ); +            continue; +        } + +        /* +         * add ei to current window +         */ +        state = 2; + +        nbits++; +        wbits |= ( ei << ( wsize - nbits ) ); + +        if( nbits == wsize ) +        { +            /* +             * X = X^wsize R^-1 mod N +             */ +            for( i = 0; i < wsize; i++ ) +                MBEDTLS_MPI_CHK( mpi_montmul( X, X, N, mm, &T ) ); + +            /* +             * X = X * W[wbits] R^-1 mod N +             */ +            MBEDTLS_MPI_CHK( mpi_montmul( X, &W[wbits], N, mm, &T ) ); + +            state--; +            nbits = 0; +            wbits = 0; +        } +    } + +    /* +     * process the remaining bits +     */ +    for( i = 0; i < nbits; i++ ) +    { +        MBEDTLS_MPI_CHK( mpi_montmul( X, X, N, mm, &T ) ); + +        wbits <<= 1; + +        if( ( wbits & ( one << wsize ) ) != 0 ) +            MBEDTLS_MPI_CHK( mpi_montmul( X, &W[1], N, mm, &T ) ); +    } + +    /* +     * X = A^E * R * R^-1 mod N = A^E mod N +     */ +    MBEDTLS_MPI_CHK( mpi_montred( X, N, mm, &T ) ); + +    if( neg && E->n != 0 && ( E->p[0] & 1 ) != 0 ) +    { +        X->s = -1; +        MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( X, N, X ) ); +    } + +cleanup: + +    for( i = ( one << ( wsize - 1 ) ); i < ( one << wsize ); i++ ) +        mbedtls_mpi_free( &W[i] ); + +    mbedtls_mpi_free( &W[1] ); mbedtls_mpi_free( &T ); mbedtls_mpi_free( &Apos ); + +    if( _RR == NULL || _RR->p == NULL ) +        mbedtls_mpi_free( &RR ); + +    return( ret ); +} + +/* + * Greatest common divisor: G = gcd(A, B)  (HAC 14.54) + */ +int mbedtls_mpi_gcd( mbedtls_mpi *G, const mbedtls_mpi *A, const mbedtls_mpi *B ) +{ +    int ret; +    size_t lz, lzt; +    mbedtls_mpi TG, TA, TB; + +    mbedtls_mpi_init( &TG ); mbedtls_mpi_init( &TA ); mbedtls_mpi_init( &TB ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TA, A ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TB, B ) ); + +    lz = mbedtls_mpi_lsb( &TA ); +    lzt = mbedtls_mpi_lsb( &TB ); + +    if( lzt < lz ) +        lz = lzt; + +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TA, lz ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TB, lz ) ); + +    TA.s = TB.s = 1; + +    while( mbedtls_mpi_cmp_int( &TA, 0 ) != 0 ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TA, mbedtls_mpi_lsb( &TA ) ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TB, mbedtls_mpi_lsb( &TB ) ) ); + +        if( mbedtls_mpi_cmp_mpi( &TA, &TB ) >= 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &TA, &TA, &TB ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TA, 1 ) ); +        } +        else +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &TB, &TB, &TA ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TB, 1 ) ); +        } +    } + +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &TB, lz ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( G, &TB ) ); + +cleanup: + +    mbedtls_mpi_free( &TG ); mbedtls_mpi_free( &TA ); mbedtls_mpi_free( &TB ); + +    return( ret ); +} + +/* + * Fill X with size bytes of random. + * + * Use a temporary bytes representation to make sure the result is the same + * regardless of the platform endianness (useful when f_rng is actually + * deterministic, eg for tests). + */ +int mbedtls_mpi_fill_random( mbedtls_mpi *X, size_t size, +                     int (*f_rng)(void *, unsigned char *, size_t), +                     void *p_rng ) +{ +    int ret; +    unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; + +    if( size > MBEDTLS_MPI_MAX_SIZE ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    MBEDTLS_MPI_CHK( f_rng( p_rng, buf, size ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( X, buf, size ) ); + +cleanup: +    mbedtls_zeroize( buf, sizeof( buf ) ); +    return( ret ); +} + +/* + * Modular inverse: X = A^-1 mod N  (HAC 14.61 / 14.64) + */ +int mbedtls_mpi_inv_mod( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *N ) +{ +    int ret; +    mbedtls_mpi G, TA, TU, U1, U2, TB, TV, V1, V2; + +    if( mbedtls_mpi_cmp_int( N, 1 ) <= 0 ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    mbedtls_mpi_init( &TA ); mbedtls_mpi_init( &TU ); mbedtls_mpi_init( &U1 ); mbedtls_mpi_init( &U2 ); +    mbedtls_mpi_init( &G ); mbedtls_mpi_init( &TB ); mbedtls_mpi_init( &TV ); +    mbedtls_mpi_init( &V1 ); mbedtls_mpi_init( &V2 ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, A, N ) ); + +    if( mbedtls_mpi_cmp_int( &G, 1 ) != 0 ) +    { +        ret = MBEDTLS_ERR_MPI_NOT_ACCEPTABLE; +        goto cleanup; +    } + +    MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &TA, A, N ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TU, &TA ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TB, N ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &TV, N ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &U1, 1 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &U2, 0 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &V1, 0 ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &V2, 1 ) ); + +    do +    { +        while( ( TU.p[0] & 1 ) == 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TU, 1 ) ); + +            if( ( U1.p[0] & 1 ) != 0 || ( U2.p[0] & 1 ) != 0 ) +            { +                MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &U1, &U1, &TB ) ); +                MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &U2, &U2, &TA ) ); +            } + +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &U1, 1 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &U2, 1 ) ); +        } + +        while( ( TV.p[0] & 1 ) == 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &TV, 1 ) ); + +            if( ( V1.p[0] & 1 ) != 0 || ( V2.p[0] & 1 ) != 0 ) +            { +                MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &V1, &V1, &TB ) ); +                MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &V2, &V2, &TA ) ); +            } + +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &V1, 1 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &V2, 1 ) ); +        } + +        if( mbedtls_mpi_cmp_mpi( &TU, &TV ) >= 0 ) +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &TU, &TU, &TV ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &U1, &U1, &V1 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &U2, &U2, &V2 ) ); +        } +        else +        { +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &TV, &TV, &TU ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &V1, &V1, &U1 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &V2, &V2, &U2 ) ); +        } +    } +    while( mbedtls_mpi_cmp_int( &TU, 0 ) != 0 ); + +    while( mbedtls_mpi_cmp_int( &V1, 0 ) < 0 ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &V1, &V1, N ) ); + +    while( mbedtls_mpi_cmp_mpi( &V1, N ) >= 0 ) +        MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &V1, &V1, N ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( X, &V1 ) ); + +cleanup: + +    mbedtls_mpi_free( &TA ); mbedtls_mpi_free( &TU ); mbedtls_mpi_free( &U1 ); mbedtls_mpi_free( &U2 ); +    mbedtls_mpi_free( &G ); mbedtls_mpi_free( &TB ); mbedtls_mpi_free( &TV ); +    mbedtls_mpi_free( &V1 ); mbedtls_mpi_free( &V2 ); + +    return( ret ); +} + +#if defined(MBEDTLS_GENPRIME) + +static const int small_prime[] = +{ +        3,    5,    7,   11,   13,   17,   19,   23, +       29,   31,   37,   41,   43,   47,   53,   59, +       61,   67,   71,   73,   79,   83,   89,   97, +      101,  103,  107,  109,  113,  127,  131,  137, +      139,  149,  151,  157,  163,  167,  173,  179, +      181,  191,  193,  197,  199,  211,  223,  227, +      229,  233,  239,  241,  251,  257,  263,  269, +      271,  277,  281,  283,  293,  307,  311,  313, +      317,  331,  337,  347,  349,  353,  359,  367, +      373,  379,  383,  389,  397,  401,  409,  419, +      421,  431,  433,  439,  443,  449,  457,  461, +      463,  467,  479,  487,  491,  499,  503,  509, +      521,  523,  541,  547,  557,  563,  569,  571, +      577,  587,  593,  599,  601,  607,  613,  617, +      619,  631,  641,  643,  647,  653,  659,  661, +      673,  677,  683,  691,  701,  709,  719,  727, +      733,  739,  743,  751,  757,  761,  769,  773, +      787,  797,  809,  811,  821,  823,  827,  829, +      839,  853,  857,  859,  863,  877,  881,  883, +      887,  907,  911,  919,  929,  937,  941,  947, +      953,  967,  971,  977,  983,  991,  997, -103 +}; + +/* + * Small divisors test (X must be positive) + * + * Return values: + * 0: no small factor (possible prime, more tests needed) + * 1: certain prime + * MBEDTLS_ERR_MPI_NOT_ACCEPTABLE: certain non-prime + * other negative: error + */ +static int mpi_check_small_factors( const mbedtls_mpi *X ) +{ +    int ret = 0; +    size_t i; +    mbedtls_mpi_uint r; + +    if( ( X->p[0] & 1 ) == 0 ) +        return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); + +    for( i = 0; small_prime[i] > 0; i++ ) +    { +        if( mbedtls_mpi_cmp_int( X, small_prime[i] ) <= 0 ) +            return( 1 ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_mod_int( &r, X, small_prime[i] ) ); + +        if( r == 0 ) +            return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); +    } + +cleanup: +    return( ret ); +} + +/* + * Miller-Rabin pseudo-primality test  (HAC 4.24) + */ +static int mpi_miller_rabin( const mbedtls_mpi *X, +                             int (*f_rng)(void *, unsigned char *, size_t), +                             void *p_rng ) +{ +    int ret, count; +    size_t i, j, k, n, s; +    mbedtls_mpi W, R, T, A, RR; + +    mbedtls_mpi_init( &W ); mbedtls_mpi_init( &R ); mbedtls_mpi_init( &T ); mbedtls_mpi_init( &A ); +    mbedtls_mpi_init( &RR ); + +    /* +     * W = |X| - 1 +     * R = W >> lsb( W ) +     */ +    MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &W, X, 1 ) ); +    s = mbedtls_mpi_lsb( &W ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R, &W ) ); +    MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &R, s ) ); + +    i = mbedtls_mpi_bitlen( X ); +    /* +     * HAC, table 4.4 +     */ +    n = ( ( i >= 1300 ) ?  2 : ( i >=  850 ) ?  3 : +          ( i >=  650 ) ?  4 : ( i >=  350 ) ?  8 : +          ( i >=  250 ) ? 12 : ( i >=  150 ) ? 18 : 27 ); + +    for( i = 0; i < n; i++ ) +    { +        /* +         * pick a random A, 1 < A < |X| - 1 +         */ +        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &A, X->n * ciL, f_rng, p_rng ) ); + +        if( mbedtls_mpi_cmp_mpi( &A, &W ) >= 0 ) +        { +            j = mbedtls_mpi_bitlen( &A ) - mbedtls_mpi_bitlen( &W ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &A, j + 1 ) ); +        } +        A.p[0] |= 3; + +        count = 0; +        do { +            MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &A, X->n * ciL, f_rng, p_rng ) ); + +            j = mbedtls_mpi_bitlen( &A ); +            k = mbedtls_mpi_bitlen( &W ); +            if (j > k) { +                MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &A, j - k ) ); +            } + +            if (count++ > 30) { +                return MBEDTLS_ERR_MPI_NOT_ACCEPTABLE; +            } + +        } while ( mbedtls_mpi_cmp_mpi( &A, &W ) >= 0 || +                  mbedtls_mpi_cmp_int( &A, 1 )  <= 0    ); + +        /* +         * A = A^R mod |X| +         */ +        MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &A, &A, &R, X, &RR ) ); + +        if( mbedtls_mpi_cmp_mpi( &A, &W ) == 0 || +            mbedtls_mpi_cmp_int( &A,  1 ) == 0 ) +            continue; + +        j = 1; +        while( j < s && mbedtls_mpi_cmp_mpi( &A, &W ) != 0 ) +        { +            /* +             * A = A * A mod |X| +             */ +            MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &A, &A ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &A, &T, X  ) ); + +            if( mbedtls_mpi_cmp_int( &A, 1 ) == 0 ) +                break; + +            j++; +        } + +        /* +         * not prime if A != |X| - 1 or A == 1 +         */ +        if( mbedtls_mpi_cmp_mpi( &A, &W ) != 0 || +            mbedtls_mpi_cmp_int( &A,  1 ) == 0 ) +        { +            ret = MBEDTLS_ERR_MPI_NOT_ACCEPTABLE; +            break; +        } +    } + +cleanup: +    mbedtls_mpi_free( &W ); mbedtls_mpi_free( &R ); mbedtls_mpi_free( &T ); mbedtls_mpi_free( &A ); +    mbedtls_mpi_free( &RR ); + +    return( ret ); +} + +/* + * Pseudo-primality test: small factors, then Miller-Rabin + */ +int mbedtls_mpi_is_prime( const mbedtls_mpi *X, +                  int (*f_rng)(void *, unsigned char *, size_t), +                  void *p_rng ) +{ +    int ret; +    mbedtls_mpi XX; + +    XX.s = 1; +    XX.n = X->n; +    XX.p = X->p; + +    if( mbedtls_mpi_cmp_int( &XX, 0 ) == 0 || +        mbedtls_mpi_cmp_int( &XX, 1 ) == 0 ) +        return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); + +    if( mbedtls_mpi_cmp_int( &XX, 2 ) == 0 ) +        return( 0 ); + +    if( ( ret = mpi_check_small_factors( &XX ) ) != 0 ) +    { +        if( ret == 1 ) +            return( 0 ); + +        return( ret ); +    } + +    return( mpi_miller_rabin( &XX, f_rng, p_rng ) ); +} + +/* + * Prime number generation + */ +int mbedtls_mpi_gen_prime( mbedtls_mpi *X, size_t nbits, int dh_flag, +                   int (*f_rng)(void *, unsigned char *, size_t), +                   void *p_rng ) +{ +    int ret; +    size_t k, n; +    mbedtls_mpi_uint r; +    mbedtls_mpi Y; + +    if( nbits < 3 || nbits > MBEDTLS_MPI_MAX_BITS ) +        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA ); + +    mbedtls_mpi_init( &Y ); + +    n = BITS_TO_LIMBS( nbits ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( X, n * ciL, f_rng, p_rng ) ); + +    k = mbedtls_mpi_bitlen( X ); +    if( k > nbits ) MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( X, k - nbits + 1 ) ); + +    mbedtls_mpi_set_bit( X, nbits-1, 1 ); + +    X->p[0] |= 1; + +    if( dh_flag == 0 ) +    { +        while( ( ret = mbedtls_mpi_is_prime( X, f_rng, p_rng ) ) != 0 ) +        { +            if( ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ) +                goto cleanup; + +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( X, X, 2 ) ); +        } +    } +    else +    { +        /* +         * An necessary condition for Y and X = 2Y + 1 to be prime +         * is X = 2 mod 3 (which is equivalent to Y = 2 mod 3). +         * Make sure it is satisfied, while keeping X = 3 mod 4 +         */ + +        X->p[0] |= 2; + +        MBEDTLS_MPI_CHK( mbedtls_mpi_mod_int( &r, X, 3 ) ); +        if( r == 0 ) +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( X, X, 8 ) ); +        else if( r == 1 ) +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( X, X, 4 ) ); + +        /* Set Y = (X-1) / 2, which is X / 2 because X is odd */ +        MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &Y, X ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &Y, 1 ) ); + +        while( 1 ) +        { +            /* +             * First, check small factors for X and Y +             * before doing Miller-Rabin on any of them +             */ +            if( ( ret = mpi_check_small_factors(  X         ) ) == 0 && +                ( ret = mpi_check_small_factors( &Y         ) ) == 0 && +                ( ret = mpi_miller_rabin(  X, f_rng, p_rng  ) ) == 0 && +                ( ret = mpi_miller_rabin( &Y, f_rng, p_rng  ) ) == 0 ) +            { +                break; +            } + +            if( ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ) +                goto cleanup; + +            /* +             * Next candidates. We want to preserve Y = (X-1) / 2 and +             * Y = 1 mod 2 and Y = 2 mod 3 (eq X = 3 mod 4 and X = 2 mod 3) +             * so up Y by 6 and X by 12. +             */ +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_int(  X,  X, 12 ) ); +            MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &Y, &Y, 6  ) ); +        } +    } + +cleanup: + +    mbedtls_mpi_free( &Y ); + +    return( ret ); +} + +#endif /* MBEDTLS_GENPRIME */ + +#if defined(MBEDTLS_SELF_TEST) + +#define GCD_PAIR_COUNT  3 + +static const int gcd_pairs[GCD_PAIR_COUNT][3] = +{ +    { 693, 609, 21 }, +    { 1764, 868, 28 }, +    { 768454923, 542167814, 1 } +}; + +/* + * Checkup routine + */ +int mbedtls_mpi_self_test( int verbose ) +{ +    int ret, i; +    mbedtls_mpi A, E, N, X, Y, U, V; + +    mbedtls_mpi_init( &A ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &N ); mbedtls_mpi_init( &X ); +    mbedtls_mpi_init( &Y ); mbedtls_mpi_init( &U ); mbedtls_mpi_init( &V ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &A, 16, +        "EFE021C2645FD1DC586E69184AF4A31E" \ +        "D5F53E93B5F123FA41680867BA110131" \ +        "944FE7952E2517337780CB0DB80E61AA" \ +        "E7C8DDC6C5C6AADEB34EB38A2F40D5E6" ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &E, 16, +        "B2E7EFD37075B9F03FF989C7C5051C20" \ +        "34D2A323810251127E7BF8625A4F49A5" \ +        "F3E27F4DA8BD59C47D6DAABA4C8127BD" \ +        "5B5C25763222FEFCCFC38B832366C29E" ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &N, 16, +        "0066A198186C18C10B2F5ED9B522752A" \ +        "9830B69916E535C8F047518A889A43A5" \ +        "94B6BED27A168D31D4A52F88925AA8F5" ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &X, &A, &N ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &U, 16, +        "602AB7ECA597A3D6B56FF9829A5E8B85" \ +        "9E857EA95A03512E2BAE7391688D264A" \ +        "A5663B0341DB9CCFD2C4C5F421FEC814" \ +        "8001B72E848A38CAE1C65F78E56ABDEF" \ +        "E12D3C039B8A02D6BE593F0BBBDA56F1" \ +        "ECF677152EF804370C1A305CAF3B5BF1" \ +        "30879B56C61DE584A0F53A2447A51E" ) ); + +    if( verbose != 0 ) +        mbedtls_printf( "  MPI test #1 (mul_mpi): " ); + +    if( mbedtls_mpi_cmp_mpi( &X, &U ) != 0 ) +    { +        if( verbose != 0 ) +            mbedtls_printf( "failed\n" ); + +        ret = 1; +        goto cleanup; +    } + +    if( verbose != 0 ) +        mbedtls_printf( "passed\n" ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &X, &Y, &A, &N ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &U, 16, +        "256567336059E52CAE22925474705F39A94" ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &V, 16, +        "6613F26162223DF488E9CD48CC132C7A" \ +        "0AC93C701B001B092E4E5B9F73BCD27B" \ +        "9EE50D0657C77F374E903CDFA4C642" ) ); + +    if( verbose != 0 ) +        mbedtls_printf( "  MPI test #2 (div_mpi): " ); + +    if( mbedtls_mpi_cmp_mpi( &X, &U ) != 0 || +        mbedtls_mpi_cmp_mpi( &Y, &V ) != 0 ) +    { +        if( verbose != 0 ) +            mbedtls_printf( "failed\n" ); + +        ret = 1; +        goto cleanup; +    } + +    if( verbose != 0 ) +        mbedtls_printf( "passed\n" ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &X, &A, &E, &N, NULL ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &U, 16, +        "36E139AEA55215609D2816998ED020BB" \ +        "BD96C37890F65171D948E9BC7CBAA4D9" \ +        "325D24D6A3C12710F10A09FA08AB87" ) ); + +    if( verbose != 0 ) +        mbedtls_printf( "  MPI test #3 (exp_mod): " ); + +    if( mbedtls_mpi_cmp_mpi( &X, &U ) != 0 ) +    { +        if( verbose != 0 ) +            mbedtls_printf( "failed\n" ); + +        ret = 1; +        goto cleanup; +    } + +    if( verbose != 0 ) +        mbedtls_printf( "passed\n" ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &X, &A, &N ) ); + +    MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &U, 16, +        "003A0AAEDD7E784FC07D8F9EC6E3BFD5" \ +        "C3DBA76456363A10869622EAC2DD84EC" \ +        "C5B8A74DAC4D09E03B5E0BE779F2DF61" ) ); + +    if( verbose != 0 ) +        mbedtls_printf( "  MPI test #4 (inv_mod): " ); + +    if( mbedtls_mpi_cmp_mpi( &X, &U ) != 0 ) +    { +        if( verbose != 0 ) +            mbedtls_printf( "failed\n" ); + +        ret = 1; +        goto cleanup; +    } + +    if( verbose != 0 ) +        mbedtls_printf( "passed\n" ); + +    if( verbose != 0 ) +        mbedtls_printf( "  MPI test #5 (simple gcd): " ); + +    for( i = 0; i < GCD_PAIR_COUNT; i++ ) +    { +        MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &X, gcd_pairs[i][0] ) ); +        MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &Y, gcd_pairs[i][1] ) ); + +        MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &A, &X, &Y ) ); + +        if( mbedtls_mpi_cmp_int( &A, gcd_pairs[i][2] ) != 0 ) +        { +            if( verbose != 0 ) +                mbedtls_printf( "failed at %d\n", i ); + +            ret = 1; +            goto cleanup; +        } +    } + +    if( verbose != 0 ) +        mbedtls_printf( "passed\n" ); + +cleanup: + +    if( ret != 0 && verbose != 0 ) +        mbedtls_printf( "Unexpected error, return code = %08X\n", ret ); + +    mbedtls_mpi_free( &A ); mbedtls_mpi_free( &E ); mbedtls_mpi_free( &N ); mbedtls_mpi_free( &X ); +    mbedtls_mpi_free( &Y ); mbedtls_mpi_free( &U ); mbedtls_mpi_free( &V ); + +    if( verbose != 0 ) +        mbedtls_printf( "\n" ); + +    return( ret ); +} + +#endif /* MBEDTLS_SELF_TEST */ + +#endif /* MBEDTLS_BIGNUM_C */  |