Coverage Report

Created: 2023-03-02 15:27

/src/mbedtls/library/base64.c
Line
Count
Source (jump to first uncovered line)
1
/*
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 *  RFC 1521 base64 encoding/decoding
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 *
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 *  Copyright The Mbed TLS Contributors
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 *  SPDX-License-Identifier: Apache-2.0
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 *
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 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
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 *  not use this file except in compliance with the License.
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 *  You may obtain a copy of the License at
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 *
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 *  http://www.apache.org/licenses/LICENSE-2.0
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 *
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 *  Unless required by applicable law or agreed to in writing, software
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 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 *  See the License for the specific language governing permissions and
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 *  limitations under the License.
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 */
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#include "common.h"
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#if defined(MBEDTLS_BASE64_C)
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#include "mbedtls/base64.h"
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#include "constant_time_internal.h"
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#include <stdint.h>
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#if defined(MBEDTLS_SELF_TEST)
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#include <string.h>
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#include "mbedtls/platform.h"
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#endif /* MBEDTLS_SELF_TEST */
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0
#define BASE64_SIZE_T_MAX   ((size_t) -1)   /* SIZE_T_MAX is not standard */
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/*
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 * Encode a buffer into base64 format
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 */
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int mbedtls_base64_encode(unsigned char *dst, size_t dlen, size_t *olen,
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                          const unsigned char *src, size_t slen)
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0
{
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0
    size_t i, n;
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0
    int C1, C2, C3;
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0
    unsigned char *p;
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0
    if (slen == 0) {
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0
        *olen = 0;
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0
        return 0;
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0
    }
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0
    n = slen / 3 + (slen % 3 != 0);
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0
    if (n > (BASE64_SIZE_T_MAX - 1) / 4) {
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0
        *olen = BASE64_SIZE_T_MAX;
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0
        return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
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0
    }
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0
    n *= 4;
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0
    if ((dlen < n + 1) || (NULL == dst)) {
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0
        *olen = n + 1;
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0
        return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
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0
    }
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0
    n = (slen / 3) * 3;
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0
    for (i = 0, p = dst; i < n; i += 3) {
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0
        C1 = *src++;
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0
        C2 = *src++;
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0
        C3 = *src++;
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0
        *p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
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0
        *p++ = mbedtls_ct_base64_enc_char((((C1 &  3) << 4) + (C2 >> 4))
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0
                                          & 0x3F);
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0
        *p++ = mbedtls_ct_base64_enc_char((((C2 & 15) << 2) + (C3 >> 6))
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0
                                          & 0x3F);
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0
        *p++ = mbedtls_ct_base64_enc_char(C3 & 0x3F);
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0
    }
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0
    if (i < slen) {
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0
        C1 = *src++;
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0
        C2 = ((i + 1) < slen) ? *src++ : 0;
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0
        *p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
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0
        *p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
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0
                                          & 0x3F);
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0
        if ((i + 1) < slen) {
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0
            *p++ = mbedtls_ct_base64_enc_char(((C2 & 15) << 2) & 0x3F);
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0
        } else {
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0
            *p++ = '=';
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0
        }
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0
        *p++ = '=';
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0
    }
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0
    *olen = p - dst;
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0
    *p = 0;
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0
    return 0;
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0
}
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/*
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 * Decode a base64-formatted buffer
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 */
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int mbedtls_base64_decode(unsigned char *dst, size_t dlen, size_t *olen,
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                          const unsigned char *src, size_t slen)
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1.38k
{
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1.38k
    size_t i; /* index in source */
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1.38k
    size_t n; /* number of digits or trailing = in source */
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1.38k
    uint32_t x; /* value accumulator */
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1.38k
    unsigned accumulated_digits = 0;
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1.38k
    unsigned equals = 0;
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1.38k
    int spaces_present = 0;
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1.38k
    unsigned char *p;
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    /* First pass: check for validity and get output length */
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1.39M
    for (i = n = 0; i < slen; i++) {
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        /* Skip spaces before checking for EOL */
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1.39M
        spaces_present = 0;
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1.39M
        while (i < slen && src[i] == ' ') {
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0
            ++i;
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0
            spaces_present = 1;
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0
        }
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        /* Spaces at end of buffer are OK */
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1.39M
        if (i == slen) {
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0
            break;
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0
        }
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1.39M
        if ((slen - i) >= 2 &&
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1.39M
            src[i] == '\r' && src[i + 1] == '\n') {
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21.7k
            continue;
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21.7k
        }
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1.37M
        if (src[i] == '\n') {
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21.7k
            continue;
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21.7k
        }
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        /* Space inside a line is an error */
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1.35M
        if (spaces_present) {
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0
            return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
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0
        }
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1.35M
        if (src[i] > 127) {
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0
            return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
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0
        }
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1.35M
        if (src[i] == '=') {
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924
            if (++equals > 2) {
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0
                return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
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0
            }
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1.35M
        } else {
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1.35M
            if (equals != 0) {
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0
                return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
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0
            }
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1.35M
            if (mbedtls_ct_base64_dec_value(src[i]) < 0) {
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0
                return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
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0
            }
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1.35M
        }
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1.35M
        n++;
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1.35M
    }
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1.38k
    if (n == 0) {
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0
        *olen = 0;
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0
        return 0;
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0
    }
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    /* The following expression is to calculate the following formula without
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     * risk of integer overflow in n:
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     *     n = ( ( n * 6 ) + 7 ) >> 3;
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     */
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1.38k
    n = (6 * (n >> 3)) + ((6 * (n & 0x7) + 7) >> 3);
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1.38k
    n -= equals;
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1.38k
    if (dst == NULL || dlen < n) {
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693
        *olen = n;
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693
        return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
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693
    }
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693
    equals = 0;
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698k
    for (x = 0, p = dst; i > 0; i--, src++) {
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698k
        if (*src == '\r' || *src == '\n' || *src == ' ') {
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21.7k
            continue;
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21.7k
        }
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676k
        x = x << 6;
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676k
        if (*src == '=') {
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462
            ++equals;
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675k
        } else {
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675k
            x |= mbedtls_ct_base64_dec_value(*src);
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675k
        }
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676k
        if (++accumulated_digits == 4) {
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169k
            accumulated_digits = 0;
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169k
            *p++ = MBEDTLS_BYTE_2(x);
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169k
            if (equals <= 1) {
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168k
                *p++ = MBEDTLS_BYTE_1(x);
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168k
            }
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169k
            if (equals <= 0) {
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168k
                *p++ = MBEDTLS_BYTE_0(x);
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168k
            }
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169k
        }
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676k
    }
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693
    *olen = p - dst;
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208
693
    return 0;
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1.38k
}
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#if defined(MBEDTLS_SELF_TEST)
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static const unsigned char base64_test_dec[64] =
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{
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    0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD,
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    0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01,
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    0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09,
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    0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13,
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    0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31,
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    0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38,
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    0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B,
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    0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97
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};
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static const unsigned char base64_test_enc[] =
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    "JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK"
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    "swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw==";
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/*
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 * Checkup routine
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 */
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int mbedtls_base64_self_test(int verbose)
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0
{
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0
    size_t len;
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0
    const unsigned char *src;
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0
    unsigned char buffer[128];
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0
    if (verbose != 0) {
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0
        mbedtls_printf("  Base64 encoding test: ");
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0
    }
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0
    src = base64_test_dec;
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0
    if (mbedtls_base64_encode(buffer, sizeof(buffer), &len, src, 64) != 0 ||
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0
        memcmp(base64_test_enc, buffer, 88) != 0) {
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0
        if (verbose != 0) {
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0
            mbedtls_printf("failed\n");
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0
        }
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0
        return 1;
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0
    }
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0
    if (verbose != 0) {
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0
        mbedtls_printf("passed\n  Base64 decoding test: ");
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0
    }
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0
    src = base64_test_enc;
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0
    if (mbedtls_base64_decode(buffer, sizeof(buffer), &len, src, 88) != 0 ||
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0
        memcmp(base64_test_dec, buffer, 64) != 0) {
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0
        if (verbose != 0) {
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0
            mbedtls_printf("failed\n");
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0
        }
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0
        return 1;
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0
    }
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0
    if (verbose != 0) {
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0
        mbedtls_printf("passed\n\n");
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0
    }
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0
    return 0;
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0
}
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#endif /* MBEDTLS_SELF_TEST */
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#endif /* MBEDTLS_BASE64_C */