| /* |
| * RFC 1521 base64 encoding/decoding |
| * |
| * Copyright The Mbed TLS Contributors |
| * 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. |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_BASE64_C) |
| |
| #include "mbedtls/base64.h" |
| #include "base64_invasive.h" |
| |
| #include <stdint.h> |
| |
| #if defined(MBEDTLS_SELF_TEST) |
| #include <string.h> |
| #if defined(MBEDTLS_PLATFORM_C) |
| #include "mbedtls/platform.h" |
| #else |
| #include <stdio.h> |
| #define mbedtls_printf printf |
| #endif /* MBEDTLS_PLATFORM_C */ |
| #endif /* MBEDTLS_SELF_TEST */ |
| |
| #define BASE64_SIZE_T_MAX ( (size_t) -1 ) /* SIZE_T_MAX is not standard */ |
| |
| /* Return 0xff if low <= c <= high, 0 otherwise. |
| * |
| * Constant flow with respect to c. |
| */ |
| MBEDTLS_STATIC_TESTABLE |
| unsigned char mbedtls_base64_mask_of_range( unsigned char low, |
| unsigned char high, |
| unsigned char c ) |
| { |
| /* low_mask is: 0 if low <= c, 0x...ff if low > c */ |
| unsigned low_mask = ( (unsigned) c - low ) >> 8; |
| /* high_mask is: 0 if c <= high, 0x...ff if c > high */ |
| unsigned high_mask = ( (unsigned) high - c ) >> 8; |
| return( ~( low_mask | high_mask ) & 0xff ); |
| } |
| |
| /* Given a value in the range 0..63, return the corresponding Base64 digit. |
| * The implementation assumes that letters are consecutive (e.g. ASCII |
| * but not EBCDIC). |
| */ |
| MBEDTLS_STATIC_TESTABLE |
| unsigned char mbedtls_base64_enc_char( unsigned char val ) |
| { |
| unsigned char digit = 0; |
| /* For each range of values, if val is in that range, mask digit with |
| * the corresponding value. Since val can only be in a single range, |
| * only at most one masking will change digit. */ |
| digit |= mbedtls_base64_mask_of_range( 0, 25, val ) & ( 'A' + val ); |
| digit |= mbedtls_base64_mask_of_range( 26, 51, val ) & ( 'a' + val - 26 ); |
| digit |= mbedtls_base64_mask_of_range( 52, 61, val ) & ( '0' + val - 52 ); |
| digit |= mbedtls_base64_mask_of_range( 62, 62, val ) & '+'; |
| digit |= mbedtls_base64_mask_of_range( 63, 63, val ) & '/'; |
| return( digit ); |
| } |
| |
| /* |
| * Encode a buffer into base64 format |
| */ |
| int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen, |
| const unsigned char *src, size_t slen ) |
| { |
| size_t i, n; |
| int C1, C2, C3; |
| unsigned char *p; |
| |
| if( slen == 0 ) |
| { |
| *olen = 0; |
| return( 0 ); |
| } |
| |
| n = slen / 3 + ( slen % 3 != 0 ); |
| |
| if( n > ( BASE64_SIZE_T_MAX - 1 ) / 4 ) |
| { |
| *olen = BASE64_SIZE_T_MAX; |
| return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); |
| } |
| |
| n *= 4; |
| |
| if( ( dlen < n + 1 ) || ( NULL == dst ) ) |
| { |
| *olen = n + 1; |
| return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); |
| } |
| |
| n = ( slen / 3 ) * 3; |
| |
| for( i = 0, p = dst; i < n; i += 3 ) |
| { |
| C1 = *src++; |
| C2 = *src++; |
| C3 = *src++; |
| |
| *p++ = mbedtls_base64_enc_char( ( C1 >> 2 ) & 0x3F ); |
| *p++ = mbedtls_base64_enc_char( ( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) |
| & 0x3F ); |
| *p++ = mbedtls_base64_enc_char( ( ( ( C2 & 15 ) << 2 ) + ( C3 >> 6 ) ) |
| & 0x3F ); |
| *p++ = mbedtls_base64_enc_char( C3 & 0x3F ); |
| } |
| |
| if( i < slen ) |
| { |
| C1 = *src++; |
| C2 = ( ( i + 1 ) < slen ) ? *src++ : 0; |
| |
| *p++ = mbedtls_base64_enc_char( ( C1 >> 2 ) & 0x3F ); |
| *p++ = mbedtls_base64_enc_char( ( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) |
| & 0x3F ); |
| |
| if( ( i + 1 ) < slen ) |
| *p++ = mbedtls_base64_enc_char( ( ( C2 & 15 ) << 2 ) & 0x3F ); |
| else *p++ = '='; |
| |
| *p++ = '='; |
| } |
| |
| *olen = p - dst; |
| *p = 0; |
| |
| return( 0 ); |
| } |
| |
| /* Given a Base64 digit, return its value. |
| * If c is not a Base64 digit ('A'..'Z', 'a'..'z', '0'..'9', '+' or '/'), |
| * return -1. |
| * |
| * The implementation assumes that letters are consecutive (e.g. ASCII |
| * but not EBCDIC). |
| * |
| * The implementation is constant-flow (no branch or memory access depending |
| * on the value of c) unless the compiler inlines and optimizes a specific |
| * access. |
| */ |
| MBEDTLS_STATIC_TESTABLE |
| signed char mbedtls_base64_dec_value( unsigned char c ) |
| { |
| unsigned char val = 0; |
| /* For each range of digits, if c is in that range, mask val with |
| * the corresponding value. Since c can only be in a single range, |
| * only at most one masking will change val. Set val to one plus |
| * the desired value so that it stays 0 if c is in none of the ranges. */ |
| val |= mbedtls_base64_mask_of_range( 'A', 'Z', c ) & ( c - 'A' + 0 + 1 ); |
| val |= mbedtls_base64_mask_of_range( 'a', 'z', c ) & ( c - 'a' + 26 + 1 ); |
| val |= mbedtls_base64_mask_of_range( '0', '9', c ) & ( c - '0' + 52 + 1 ); |
| val |= mbedtls_base64_mask_of_range( '+', '+', c ) & ( c - '+' + 62 + 1 ); |
| val |= mbedtls_base64_mask_of_range( '/', '/', c ) & ( c - '/' + 63 + 1 ); |
| /* At this point, val is 0 if c is an invalid digit and v+1 if c is |
| * a digit with the value v. */ |
| return( val - 1 ); |
| } |
| |
| /* |
| * Decode a base64-formatted buffer |
| */ |
| int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen, |
| const unsigned char *src, size_t slen ) |
| { |
| size_t i; /* index in source */ |
| size_t n; /* number of digits or trailing = in source */ |
| uint32_t x; /* value accumulator */ |
| unsigned accumulated_digits = 0; |
| unsigned equals = 0; |
| int spaces_present = 0; |
| unsigned char *p; |
| |
| /* First pass: check for validity and get output length */ |
| for( i = n = 0; i < slen; i++ ) |
| { |
| /* Skip spaces before checking for EOL */ |
| spaces_present = 0; |
| while( i < slen && src[i] == ' ' ) |
| { |
| ++i; |
| spaces_present = 1; |
| } |
| |
| /* Spaces at end of buffer are OK */ |
| if( i == slen ) |
| break; |
| |
| if( ( slen - i ) >= 2 && |
| src[i] == '\r' && src[i + 1] == '\n' ) |
| continue; |
| |
| if( src[i] == '\n' ) |
| continue; |
| |
| /* Space inside a line is an error */ |
| if( spaces_present ) |
| return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); |
| |
| if( src[i] > 127 ) |
| return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); |
| |
| if( src[i] == '=' ) |
| { |
| if( ++equals > 2 ) |
| return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); |
| } |
| else |
| { |
| if( equals != 0 ) |
| return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); |
| if( mbedtls_base64_dec_value( src[i] ) < 0 ) |
| return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); |
| } |
| n++; |
| } |
| |
| if( n == 0 ) |
| { |
| *olen = 0; |
| return( 0 ); |
| } |
| |
| /* The following expression is to calculate the following formula without |
| * risk of integer overflow in n: |
| * n = ( ( n * 6 ) + 7 ) >> 3; |
| */ |
| n = ( 6 * ( n >> 3 ) ) + ( ( 6 * ( n & 0x7 ) + 7 ) >> 3 ); |
| n -= equals; |
| |
| if( dst == NULL || dlen < n ) |
| { |
| *olen = n; |
| return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); |
| } |
| |
| equals = 0; |
| for( x = 0, p = dst; i > 0; i--, src++ ) |
| { |
| if( *src == '\r' || *src == '\n' || *src == ' ' ) |
| continue; |
| |
| x = x << 6; |
| if( *src == '=' ) |
| ++equals; |
| else |
| x |= mbedtls_base64_dec_value( *src ); |
| |
| if( ++accumulated_digits == 4 ) |
| { |
| accumulated_digits = 0; |
| *p++ = MBEDTLS_BYTE_2( x ); |
| if( equals <= 1 ) *p++ = MBEDTLS_BYTE_1( x ); |
| if( equals <= 0 ) *p++ = MBEDTLS_BYTE_0( x ); |
| } |
| } |
| |
| *olen = p - dst; |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SELF_TEST) |
| |
| static const unsigned char base64_test_dec[64] = |
| { |
| 0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD, |
| 0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01, |
| 0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09, |
| 0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13, |
| 0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31, |
| 0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38, |
| 0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B, |
| 0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97 |
| }; |
| |
| static const unsigned char base64_test_enc[] = |
| "JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK" |
| "swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw=="; |
| |
| /* |
| * Checkup routine |
| */ |
| int mbedtls_base64_self_test( int verbose ) |
| { |
| size_t len; |
| const unsigned char *src; |
| unsigned char buffer[128]; |
| |
| if( verbose != 0 ) |
| mbedtls_printf( " Base64 encoding test: " ); |
| |
| src = base64_test_dec; |
| |
| if( mbedtls_base64_encode( buffer, sizeof( buffer ), &len, src, 64 ) != 0 || |
| memcmp( base64_test_enc, buffer, 88 ) != 0 ) |
| { |
| if( verbose != 0 ) |
| mbedtls_printf( "failed\n" ); |
| |
| return( 1 ); |
| } |
| |
| if( verbose != 0 ) |
| mbedtls_printf( "passed\n Base64 decoding test: " ); |
| |
| src = base64_test_enc; |
| |
| if( mbedtls_base64_decode( buffer, sizeof( buffer ), &len, src, 88 ) != 0 || |
| memcmp( base64_test_dec, buffer, 64 ) != 0 ) |
| { |
| if( verbose != 0 ) |
| mbedtls_printf( "failed\n" ); |
| |
| return( 1 ); |
| } |
| |
| if( verbose != 0 ) |
| mbedtls_printf( "passed\n\n" ); |
| |
| return( 0 ); |
| } |
| |
| #endif /* MBEDTLS_SELF_TEST */ |
| |
| #endif /* MBEDTLS_BASE64_C */ |