library/base64.c - mirror/mbed-tls.git - TrustedFirmware Git Browser

 /*
  *  RFC 1521 base64 encoding/decoding
  *
  *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */

 #include <limits.h>

 #include "common.h"

 #if defined(MBEDTLS_BASE64_C)

 #include "mbedtls/base64.h"
 #include "base64_internal.h"
 #include "constant_time_internal.h"

 #include <stdint.h>

 #if defined(MBEDTLS_SELF_TEST)
 #include <string.h>
 #include "mbedtls/platform.h"
 #endif /* MBEDTLS_SELF_TEST */

 MBEDTLS_STATIC_TESTABLE
 unsigned char mbedtls_ct_base64_enc_char(unsigned char value)
 {
     unsigned char digit = 0;
     /* For each range of values, if value is in that range, mask digit with
      * the corresponding value. Since value can only be in a single range,
      * only at most one masking will change digit. */
     digit |= mbedtls_ct_uchar_in_range_if(0, 25, value, 'A' + value);
     digit |= mbedtls_ct_uchar_in_range_if(26, 51, value, 'a' + value - 26);
     digit |= mbedtls_ct_uchar_in_range_if(52, 61, value, '0' + value - 52);
     digit |= mbedtls_ct_uchar_in_range_if(62, 62, value, '+');
     digit |= mbedtls_ct_uchar_in_range_if(63, 63, value, '/');
     return digit;
 }

 MBEDTLS_STATIC_TESTABLE
 signed char mbedtls_ct_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_ct_uchar_in_range_if('A', 'Z', c, c - 'A' +  0 + 1);
     val |= mbedtls_ct_uchar_in_range_if('a', 'z', c, c - 'a' + 26 + 1);
     val |= mbedtls_ct_uchar_in_range_if('0', '9', c, c - '0' + 52 + 1);
     val |= mbedtls_ct_uchar_in_range_if('+', '+', c, c - '+' + 62 + 1);
     val |= mbedtls_ct_uchar_in_range_if('/', '/', 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;
 }

 /*
  * 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 > (SIZE_MAX - 1) / 4) {
         *olen = SIZE_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_ct_base64_enc_char((C1 >> 2) & 0x3F);
         *p++ = mbedtls_ct_base64_enc_char((((C1 &  3) << 4) + (C2 >> 4))
                                           & 0x3F);
         *p++ = mbedtls_ct_base64_enc_char((((C2 & 15) << 2) + (C3 >> 6))
                                           & 0x3F);
         *p++ = mbedtls_ct_base64_enc_char(C3 & 0x3F);
     }

     if (i < slen) {
         C1 = *src++;
         C2 = ((i + 1) < slen) ? *src++ : 0;

         *p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
         *p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
                                           & 0x3F);

         if ((i + 1) < slen) {
             *p++ = mbedtls_ct_base64_enc_char(((C2 & 15) << 2) & 0x3F);
         } else {
             *p++ = '=';
         }

         *p++ = '=';
     }

     *olen = (size_t) (p - dst);
     *p = 0;

     return 0;
 }

 /*
  * 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_ct_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_ct_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 = (size_t) (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 */
	/*
	* RFC 1521 base64 encoding/decoding
	*
	* Copyright The Mbed TLS Contributors
	* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
	*/

	#include <limits.h>

	#include "common.h"

	#if defined(MBEDTLS_BASE64_C)

	#include "mbedtls/base64.h"
	#include "base64_internal.h"
	#include "constant_time_internal.h"

	#include <stdint.h>

	#if defined(MBEDTLS_SELF_TEST)
	#include <string.h>
	#include "mbedtls/platform.h"
	#endif /* MBEDTLS_SELF_TEST */

	MBEDTLS_STATIC_TESTABLE
	unsigned char mbedtls_ct_base64_enc_char(unsigned char value)
	{
	unsigned char digit = 0;
	/* For each range of values, if value is in that range, mask digit with
	* the corresponding value. Since value can only be in a single range,
	* only at most one masking will change digit. */
	digit \|= mbedtls_ct_uchar_in_range_if(0, 25, value, 'A' + value);
	digit \|= mbedtls_ct_uchar_in_range_if(26, 51, value, 'a' + value - 26);
	digit \|= mbedtls_ct_uchar_in_range_if(52, 61, value, '0' + value - 52);
	digit \|= mbedtls_ct_uchar_in_range_if(62, 62, value, '+');
	digit \|= mbedtls_ct_uchar_in_range_if(63, 63, value, '/');
	return digit;
	}

	MBEDTLS_STATIC_TESTABLE
	signed char mbedtls_ct_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_ct_uchar_in_range_if('A', 'Z', c, c - 'A' + 0 + 1);
	val \|= mbedtls_ct_uchar_in_range_if('a', 'z', c, c - 'a' + 26 + 1);
	val \|= mbedtls_ct_uchar_in_range_if('0', '9', c, c - '0' + 52 + 1);
	val \|= mbedtls_ct_uchar_in_range_if('+', '+', c, c - '+' + 62 + 1);
	val \|= mbedtls_ct_uchar_in_range_if('/', '/', 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;
	}

	/*
	* 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 > (SIZE_MAX - 1) / 4) {
	*olen = SIZE_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_ct_base64_enc_char((C1 >> 2) & 0x3F);
	*p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
	& 0x3F);
	*p++ = mbedtls_ct_base64_enc_char((((C2 & 15) << 2) + (C3 >> 6))
	& 0x3F);
	*p++ = mbedtls_ct_base64_enc_char(C3 & 0x3F);
	}

	if (i < slen) {
	C1 = *src++;
	C2 = ((i + 1) < slen) ? *src++ : 0;

	*p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
	*p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
	& 0x3F);

	if ((i + 1) < slen) {
	*p++ = mbedtls_ct_base64_enc_char(((C2 & 15) << 2) & 0x3F);
	} else {
	*p++ = '=';
	}

	*p++ = '=';
	}

	*olen = (size_t) (p - dst);
	*p = 0;

	return 0;
	}

	/*
	* 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_ct_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_ct_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 = (size_t) (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 */