/src/mbedtls/library/base64.c

Source (jump to first uncovered line)
/*
 *  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 "constant_time_internal.h"

#include <stdint.h>

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

#define BASE64_SIZE_T_MAX   ((size_t) -1)   /* SIZE_T_MAX is not standard */

/*
 * 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_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 = 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 = 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 */

Coverage Report

Created: 2024-01-20 12:33

Line	Count	Source (jump to first uncovered line)
1		/*
2		* RFC 1521 base64 encoding/decoding
3		*
4		* Copyright The Mbed TLS Contributors
5		* SPDX-License-Identifier: Apache-2.0
6		*
7		* Licensed under the Apache License, Version 2.0 (the "License"); you may
8		* not use this file except in compliance with the License.
9		* You may obtain a copy of the License at
10		*
11		* http://www.apache.org/licenses/LICENSE-2.0
12		*
13		* Unless required by applicable law or agreed to in writing, software
14		* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15		* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16		* See the License for the specific language governing permissions and
17		* limitations under the License.
18		*/
19
20		#include "common.h"
21
22		#if defined(MBEDTLS_BASE64_C)
23
24		#include "mbedtls/base64.h"
25		#include "constant_time_internal.h"
26
27		#include <stdint.h>
28
29		#if defined(MBEDTLS_SELF_TEST)
30		#include <string.h>
31		#include "mbedtls/platform.h"
32		#endif /* MBEDTLS_SELF_TEST */
33
34	0	#define BASE64_SIZE_T_MAX ((size_t) -1) /* SIZE_T_MAX is not standard */
35
36		/*
37		* Encode a buffer into base64 format
38		*/
39		int mbedtls_base64_encode(unsigned char dst, size_t dlen, size_t olen,
40		const unsigned char *src, size_t slen)
41	0	{
42	0	size_t i, n;
43	0	int C1, C2, C3;
44	0	unsigned char *p;
45
46	0	if (slen == 0) {
47	0	*olen = 0;
48	0	return 0;
49	0	}
50
51	0	n = slen / 3 + (slen % 3 != 0);
52
53	0	if (n > (BASE64_SIZE_T_MAX - 1) / 4) {
54	0	*olen = BASE64_SIZE_T_MAX;
55	0	return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
56	0	}
57
58	0	n *= 4;
59
60	0	if ((dlen < n + 1) \|\| (NULL == dst)) {
61	0	*olen = n + 1;
62	0	return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
63	0	}
64
65	0	n = (slen / 3) * 3;
66
67	0	for (i = 0, p = dst; i < n; i += 3) {
68	0	C1 = *src++;
69	0	C2 = *src++;
70	0	C3 = *src++;
71
72	0	*p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
73	0	*p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
74	0	& 0x3F);
75	0	*p++ = mbedtls_ct_base64_enc_char((((C2 & 15) << 2) + (C3 >> 6))
76	0	& 0x3F);
77	0	*p++ = mbedtls_ct_base64_enc_char(C3 & 0x3F);
78	0	}
79
80	0	if (i < slen) {
81	0	C1 = *src++;
82	0	C2 = ((i + 1) < slen) ? *src++ : 0;
83
84	0	*p++ = mbedtls_ct_base64_enc_char((C1 >> 2) & 0x3F);
85	0	*p++ = mbedtls_ct_base64_enc_char((((C1 & 3) << 4) + (C2 >> 4))
86	0	& 0x3F);
87
88	0	if ((i + 1) < slen) {
89	0	*p++ = mbedtls_ct_base64_enc_char(((C2 & 15) << 2) & 0x3F);
90	0	} else {
91	0	*p++ = '=';
92	0	}
93
94	0	*p++ = '=';
95	0	}
96
97	0	*olen = p - dst;
98	0	*p = 0;
99
100	0	return 0;
101	0	}
102
103		/*
104		* Decode a base64-formatted buffer
105		*/
106		int mbedtls_base64_decode(unsigned char dst, size_t dlen, size_t olen,
107		const unsigned char *src, size_t slen)
108	7.60k	{
109	7.60k	size_t i; /* index in source */
110	7.60k	size_t n; /* number of digits or trailing = in source */
111	7.60k	uint32_t x; /* value accumulator */
112	7.60k	unsigned accumulated_digits = 0;
113	7.60k	unsigned equals = 0;
114	7.60k	int spaces_present = 0;
115	7.60k	unsigned char *p;
116
117		/* First pass: check for validity and get output length */
118	7.67M	for (i = n = 0; i < slen; i++) {
119		/* Skip spaces before checking for EOL */
120	7.66M	spaces_present = 0;
121	7.66M	while (i < slen && src[i] == ' ') {
122	0	++i;
123	0	spaces_present = 1;
124	0	}
125
126		/* Spaces at end of buffer are OK */
127	7.66M	if (i == slen) {
128	0	break;
129	0	}
130
131	7.66M	if ((slen - i) >= 2 &&
132	7.66M	src[i] == '\r' && src[i + 1] == '\n') {
133	119k	continue;
134	119k	}
135
136	7.54M	if (src[i] == '\n') {
137	119k	continue;
138	119k	}
139
140		/* Space inside a line is an error */
141	7.42M	if (spaces_present) {
142	0	return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
143	0	}
144
145	7.42M	if (src[i] > 127) {
146	0	return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
147	0	}
148
149	7.42M	if (src[i] == '=') {
150	5.07k	if (++equals > 2) {
151	0	return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
152	0	}
153	7.42M	} else {
154	7.42M	if (equals != 0) {
155	0	return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
156	0	}
157	7.42M	if (mbedtls_ct_base64_dec_value(src[i]) < 0) {
158	0	return MBEDTLS_ERR_BASE64_INVALID_CHARACTER;
159	0	}
160	7.42M	}
161	7.42M	n++;
162	7.42M	}
163
164	7.60k	if (n == 0) {
165	0	*olen = 0;
166	0	return 0;
167	0	}
168
169		/* The following expression is to calculate the following formula without
170		* risk of integer overflow in n:
171		* n = ( ( n * 6 ) + 7 ) >> 3;
172		*/
173	7.60k	n = (6 * (n >> 3)) + ((6 * (n & 0x7) + 7) >> 3);
174	7.60k	n -= equals;
175
176	7.60k	if (dst == NULL \|\| dlen < n) {
177	3.80k	*olen = n;
178	3.80k	return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL;
179	3.80k	}
180
181	3.80k	equals = 0;
182	3.83M	for (x = 0, p = dst; i > 0; i--, src++) {
183	3.83M	if (src == '\r' \|\| src == '\n' \|\| *src == ' ') {
184	119k	continue;
185	119k	}
186
187	3.71M	x = x << 6;
188	3.71M	if (*src == '=') {
189	2.53k	++equals;
190	3.71M	} else {
191	3.71M	x \|= mbedtls_ct_base64_dec_value(*src);
192	3.71M	}
193
194	3.71M	if (++accumulated_digits == 4) {
195	928k	accumulated_digits = 0;
196	928k	*p++ = MBEDTLS_BYTE_2(x);
197	928k	if (equals <= 1) {
198	926k	*p++ = MBEDTLS_BYTE_1(x);
199	926k	}
200	928k	if (equals <= 0) {
201	926k	*p++ = MBEDTLS_BYTE_0(x);
202	926k	}
203	928k	}
204	3.71M	}
205
206	3.80k	*olen = p - dst;
207
208	3.80k	return 0;
209	7.60k	}
210
211		#if defined(MBEDTLS_SELF_TEST)
212
213		static const unsigned char base64_test_dec[64] =
214		{
215		0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD,
216		0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01,
217		0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09,
218		0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13,
219		0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31,
220		0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38,
221		0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B,
222		0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97
223		};
224
225		static const unsigned char base64_test_enc[] =
226		"JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK"
227		"swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw==";
228
229		/*
230		* Checkup routine
231		*/
232		int mbedtls_base64_self_test(int verbose)
233	0	{
234	0	size_t len;
235	0	const unsigned char *src;
236	0	unsigned char buffer[128];
237
238	0	if (verbose != 0) {
239	0	mbedtls_printf(" Base64 encoding test: ");
240	0	}
241
242	0	src = base64_test_dec;
243
244	0	if (mbedtls_base64_encode(buffer, sizeof(buffer), &len, src, 64) != 0 \|\|
245	0	memcmp(base64_test_enc, buffer, 88) != 0) {
246	0	if (verbose != 0) {
247	0	mbedtls_printf("failed\n");
248	0	}
249
250	0	return 1;
251	0	}
252
253	0	if (verbose != 0) {
254	0	mbedtls_printf("passed\n Base64 decoding test: ");
255	0	}
256
257	0	src = base64_test_enc;
258
259	0	if (mbedtls_base64_decode(buffer, sizeof(buffer), &len, src, 88) != 0 \|\|
260	0	memcmp(base64_test_dec, buffer, 64) != 0) {
261	0	if (verbose != 0) {
262	0	mbedtls_printf("failed\n");
263	0	}
264
265	0	return 1;
266	0	}
267
268	0	if (verbose != 0) {
269	0	mbedtls_printf("passed\n\n");
270	0	}
271
272	0	return 0;
273	0	}
274
275		#endif /* MBEDTLS_SELF_TEST */
276
277		#endif /* MBEDTLS_BASE64_C */