diff options
Diffstat (limited to 'thirdparty/mbedtls/library/base64.c')
| -rw-r--r-- | thirdparty/mbedtls/library/base64.c | 131 |
1 files changed, 120 insertions, 11 deletions
diff --git a/thirdparty/mbedtls/library/base64.c b/thirdparty/mbedtls/library/base64.c index bfafb05353..692e11e3fa 100644 --- a/thirdparty/mbedtls/library/base64.c +++ b/thirdparty/mbedtls/library/base64.c @@ -97,6 +97,99 @@ static const unsigned char base64_dec_map[128] = #define BASE64_SIZE_T_MAX ( (size_t) -1 ) /* SIZE_T_MAX is not standard */ /* + * Constant flow conditional assignment to unsigned char + */ +static void mbedtls_base64_cond_assign_uchar( unsigned char * dest, const unsigned char * const src, + unsigned char condition ) +{ + /* MSVC has a warning about unary minus on unsigned integer types, + * but this is well-defined and precisely what we want to do here. */ +#if defined(_MSC_VER) +#pragma warning( push ) +#pragma warning( disable : 4146 ) +#endif + + /* Generate bitmask from condition, mask will either be 0xFF or 0 */ + unsigned char mask = ( condition | -condition ); + mask >>= 7; + mask = -mask; + +#if defined(_MSC_VER) +#pragma warning( pop ) +#endif + + *dest = ( ( *src ) & mask ) | ( ( *dest ) & ~mask ); +} + +/* + * Constant flow conditional assignment to uint_32 + */ +static void mbedtls_base64_cond_assign_uint32( uint32_t * dest, const uint32_t src, + uint32_t condition ) +{ + /* MSVC has a warning about unary minus on unsigned integer types, + * but this is well-defined and precisely what we want to do here. */ +#if defined(_MSC_VER) +#pragma warning( push ) +#pragma warning( disable : 4146 ) +#endif + + /* Generate bitmask from condition, mask will either be 0xFFFFFFFF or 0 */ + uint32_t mask = ( condition | -condition ); + mask >>= 31; + mask = -mask; + +#if defined(_MSC_VER) +#pragma warning( pop ) +#endif + + *dest = ( src & mask ) | ( ( *dest ) & ~mask ); +} + +/* + * Constant flow check for equality + */ +static unsigned char mbedtls_base64_eq( size_t in_a, size_t in_b ) +{ + size_t difference = in_a ^ in_b; + + /* MSVC has a warning about unary minus on unsigned integer types, + * but this is well-defined and precisely what we want to do here. */ +#if defined(_MSC_VER) +#pragma warning( push ) +#pragma warning( disable : 4146 ) +#endif + + difference |= -difference; + +#if defined(_MSC_VER) +#pragma warning( pop ) +#endif + + /* cope with the varying size of size_t per platform */ + difference >>= ( sizeof( difference ) * 8 - 1 ); + + return (unsigned char) ( 1 ^ difference ); +} + +/* + * Constant flow lookup into table. + */ +static unsigned char mbedtls_base64_table_lookup( const unsigned char * const table, + const size_t table_size, const size_t table_index ) +{ + size_t i; + unsigned char result = 0; + + for( i = 0; i < table_size; ++i ) + { + mbedtls_base64_cond_assign_uchar( &result, &table[i], mbedtls_base64_eq( i, table_index ) ); + } + + return result; +} + +/* * Encode a buffer into base64 format */ int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen, @@ -136,10 +229,17 @@ int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen, C2 = *src++; C3 = *src++; - *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; - *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; - *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F]; - *p++ = base64_enc_map[C3 & 0x3F]; + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( C1 >> 2 ) & 0x3F ) ); + + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F ) ); + + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( ( ( C2 & 15 ) << 2 ) + ( C3 >> 6 ) ) & 0x3F ) ); + + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( C3 & 0x3F ) ); } if( i < slen ) @@ -147,11 +247,15 @@ int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen, C1 = *src++; C2 = ( ( i + 1 ) < slen ) ? *src++ : 0; - *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; - *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( C1 >> 2 ) & 0x3F ) ); + + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F ) ); if( ( i + 1 ) < slen ) - *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F]; + *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ), + ( ( ( C2 & 15 ) << 2 ) & 0x3F ) ); else *p++ = '='; *p++ = '='; @@ -172,6 +276,7 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen, size_t i, n; uint32_t j, x; unsigned char *p; + unsigned char dec_map_lookup; /* First pass: check for validity and get output length */ for( i = n = j = 0; i < slen; i++ ) @@ -202,10 +307,12 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen, if( src[i] == '=' && ++j > 2 ) return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); - if( src[i] > 127 || base64_dec_map[src[i]] == 127 ) + dec_map_lookup = mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), src[i] ); + + if( src[i] > 127 || dec_map_lookup == 127 ) return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); - if( base64_dec_map[src[i]] < 64 && j != 0 ) + if( dec_map_lookup < 64 && j != 0 ) return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); n++; @@ -235,8 +342,10 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen, if( *src == '\r' || *src == '\n' || *src == ' ' ) continue; - j -= ( base64_dec_map[*src] == 64 ); - x = ( x << 6 ) | ( base64_dec_map[*src] & 0x3F ); + dec_map_lookup = mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), *src ); + + mbedtls_base64_cond_assign_uint32( &j, j - 1, mbedtls_base64_eq( dec_map_lookup, 64 ) ); + x = ( x << 6 ) | ( dec_map_lookup & 0x3F ); if( ++n == 4 ) { |