/src/mbedtls/library/asn1write.c

Source (jump to first uncovered line)
/*
 * ASN.1 buffer writing functionality
 *
 *  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_ASN1_WRITE_C)

#include "mbedtls/asn1write.h"
#include "mbedtls/error.h"

#include <string.h>

#include "mbedtls/platform.h"

int mbedtls_asn1_write_len(unsigned char **p, const unsigned char *start, size_t len)
{
    if (len < 0x80) {
        if (*p - start < 1) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = (unsigned char) len;
        return 1;
    }

    if (len <= 0xFF) {
        if (*p - start < 2) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = (unsigned char) len;
        *--(*p) = 0x81;
        return 2;
    }

    if (len <= 0xFFFF) {
        if (*p - start < 3) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = MBEDTLS_BYTE_0(len);
        *--(*p) = MBEDTLS_BYTE_1(len);
        *--(*p) = 0x82;
        return 3;
    }

    if (len <= 0xFFFFFF) {
        if (*p - start < 4) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = MBEDTLS_BYTE_0(len);
        *--(*p) = MBEDTLS_BYTE_1(len);
        *--(*p) = MBEDTLS_BYTE_2(len);
        *--(*p) = 0x83;
        return 4;
    }

    int len_is_valid = 1;
#if SIZE_MAX > 0xFFFFFFFF
    len_is_valid = (len <= 0xFFFFFFFF);
#endif
    if (len_is_valid) {
        if (*p - start < 5) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = MBEDTLS_BYTE_0(len);
        *--(*p) = MBEDTLS_BYTE_1(len);
        *--(*p) = MBEDTLS_BYTE_2(len);
        *--(*p) = MBEDTLS_BYTE_3(len);
        *--(*p) = 0x84;
        return 5;
    }

    return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
}

int mbedtls_asn1_write_tag(unsigned char **p, const unsigned char *start, unsigned char tag)
{
    if (*p - start < 1) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    *--(*p) = tag;

    return 1;
}

int mbedtls_asn1_write_raw_buffer(unsigned char **p, const unsigned char *start,
                                  const unsigned char *buf, size_t size)
{
    size_t len = 0;

    if (*p < start || (size_t) (*p - start) < size) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    len = size;
    (*p) -= len;
    memcpy(*p, buf, len);

    return (int) len;
}

#if defined(MBEDTLS_BIGNUM_C)
int mbedtls_asn1_write_mpi(unsigned char **p, const unsigned char *start, const mbedtls_mpi *X)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    // Write the MPI
    //
    len = mbedtls_mpi_size(X);

    /* DER represents 0 with a sign bit (0=nonnegative) and 7 value bits, not
     * as 0 digits. We need to end up with 020100, not with 0200. */
    if (len == 0) {
        len = 1;
    }

    if (*p < start || (size_t) (*p - start) < len) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    (*p) -= len;
    MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(X, *p, len));

    // DER format assumes 2s complement for numbers, so the leftmost bit
    // should be 0 for positive numbers and 1 for negative numbers.
    //
    if (X->s == 1 && **p & 0x80) {
        if (*p - start < 1) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }

        *--(*p) = 0x00;
        len += 1;
    }

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_INTEGER));

    ret = (int) len;

cleanup:
    return ret;
}
#endif /* MBEDTLS_BIGNUM_C */

int mbedtls_asn1_write_null(unsigned char **p, const unsigned char *start)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    // Write NULL
    //
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, 0));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_NULL));

    return (int) len;
}

int mbedtls_asn1_write_oid(unsigned char **p, const unsigned char *start,
                           const char *oid, size_t oid_len)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
                                                            (const unsigned char *) oid, oid_len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID));

    return (int) len;
}

int mbedtls_asn1_write_algorithm_identifier(unsigned char **p, const unsigned char *start,
                                            const char *oid, size_t oid_len,
                                            size_t par_len)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    if (par_len == 0) {
        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_null(p, start));
    } else {
        len += par_len;
    }

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid, oid_len));

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
                                                     MBEDTLS_ASN1_CONSTRUCTED |
                                                     MBEDTLS_ASN1_SEQUENCE));

    return (int) len;
}

int mbedtls_asn1_write_bool(unsigned char **p, const unsigned char *start, int boolean)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    if (*p - start < 1) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    *--(*p) = (boolean) ? 255 : 0;
    len++;

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BOOLEAN));

    return (int) len;
}

static int asn1_write_tagged_int(unsigned char **p, const unsigned char *start, int val, int tag)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    do {
        if (*p - start < 1) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }
        len += 1;
        *--(*p) = val & 0xff;
        val >>= 8;
    } while (val > 0);

    if (**p & 0x80) {
        if (*p - start < 1) {
            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
        }
        *--(*p) = 0x00;
        len += 1;
    }

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));

    return (int) len;
}

int mbedtls_asn1_write_int(unsigned char **p, const unsigned char *start, int val)
{
    return asn1_write_tagged_int(p, start, val, MBEDTLS_ASN1_INTEGER);
}

int mbedtls_asn1_write_enum(unsigned char **p, const unsigned char *start, int val)
{
    return asn1_write_tagged_int(p, start, val, MBEDTLS_ASN1_ENUMERATED);
}

int mbedtls_asn1_write_tagged_string(unsigned char **p, const unsigned char *start, int tag,
                                     const char *text, size_t text_len)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
                                                            (const unsigned char *) text,
                                                            text_len));

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));

    return (int) len;
}

int mbedtls_asn1_write_utf8_string(unsigned char **p, const unsigned char *start,
                                   const char *text, size_t text_len)
{
    return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len);
}

int mbedtls_asn1_write_printable_string(unsigned char **p, const unsigned char *start,
                                        const char *text, size_t text_len)
{
    return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text,
                                            text_len);
}

int mbedtls_asn1_write_ia5_string(unsigned char **p, const unsigned char *start,
                                  const char *text, size_t text_len)
{
    return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len);
}

int mbedtls_asn1_write_named_bitstring(unsigned char **p,
                                       const unsigned char *start,
                                       const unsigned char *buf,
                                       size_t bits)
{
    size_t unused_bits, byte_len;
    const unsigned char *cur_byte;
    unsigned char cur_byte_shifted;
    unsigned char bit;

    byte_len = (bits + 7) / 8;
    unused_bits = (byte_len * 8) - bits;

    /*
     * Named bitstrings require that trailing 0s are excluded in the encoding
     * of the bitstring. Trailing 0s are considered part of the 'unused' bits
     * when encoding this value in the first content octet
     */
    if (bits != 0) {
        cur_byte = buf + byte_len - 1;
        cur_byte_shifted = *cur_byte >> unused_bits;

        for (;;) {
            bit = cur_byte_shifted & 0x1;
            cur_byte_shifted >>= 1;

            if (bit != 0) {
                break;
            }

            bits--;
            if (bits == 0) {
                break;
            }

            if (bits % 8 == 0) {
                cur_byte_shifted = *--cur_byte;
            }
        }
    }

    return mbedtls_asn1_write_bitstring(p, start, buf, bits);
}

int mbedtls_asn1_write_bitstring(unsigned char **p, const unsigned char *start,
                                 const unsigned char *buf, size_t bits)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;
    size_t unused_bits, byte_len;

    byte_len = (bits + 7) / 8;
    unused_bits = (byte_len * 8) - bits;

    if (*p < start || (size_t) (*p - start) < byte_len + 1) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    len = byte_len + 1;

    /* Write the bitstring. Ensure the unused bits are zeroed */
    if (byte_len > 0) {
        byte_len--;
        *--(*p) = buf[byte_len] & ~((0x1 << unused_bits) - 1);
        (*p) -= byte_len;
        memcpy(*p, buf, byte_len);
    }

    /* Write unused bits */
    *--(*p) = (unsigned char) unused_bits;

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING));

    return (int) len;
}

int mbedtls_asn1_write_octet_string(unsigned char **p, const unsigned char *start,
                                    const unsigned char *buf, size_t size)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, buf, size));

    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING));

    return (int) len;
}


/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
 * which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
static mbedtls_asn1_named_data *asn1_find_named_data(
    mbedtls_asn1_named_data *list,
    const char *oid, size_t len)
{
    while (list != NULL) {
        if (list->oid.len == len &&
            memcmp(list->oid.p, oid, len) == 0) {
            break;
        }

        list = list->next;
    }

    return list;
}

mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
    mbedtls_asn1_named_data **head,
    const char *oid, size_t oid_len,
    const unsigned char *val,
    size_t val_len)
{
    mbedtls_asn1_named_data *cur;

    if ((cur = asn1_find_named_data(*head, oid, oid_len)) == NULL) {
        // Add new entry if not present yet based on OID
        //
        cur = (mbedtls_asn1_named_data *) mbedtls_calloc(1,
                                                         sizeof(mbedtls_asn1_named_data));
        if (cur == NULL) {
            return NULL;
        }

        cur->oid.len = oid_len;
        cur->oid.p = mbedtls_calloc(1, oid_len);
        if (cur->oid.p == NULL) {
            mbedtls_free(cur);
            return NULL;
        }

        memcpy(cur->oid.p, oid, oid_len);

        cur->val.len = val_len;
        if (val_len != 0) {
            cur->val.p = mbedtls_calloc(1, val_len);
            if (cur->val.p == NULL) {
                mbedtls_free(cur->oid.p);
                mbedtls_free(cur);
                return NULL;
            }
        }

        cur->next = *head;
        *head = cur;
    } else if (val_len == 0) {
        mbedtls_free(cur->val.p);
        cur->val.p = NULL;
    } else if (cur->val.len != val_len) {
        /*
         * Enlarge existing value buffer if needed
         * Preserve old data until the allocation succeeded, to leave list in
         * a consistent state in case allocation fails.
         */
        void *p = mbedtls_calloc(1, val_len);
        if (p == NULL) {
            return NULL;
        }

        mbedtls_free(cur->val.p);
        cur->val.p = p;
        cur->val.len = val_len;
    }

    if (val != NULL && val_len != 0) {
        memcpy(cur->val.p, val, val_len);
    }

    return cur;
}
#endif /* MBEDTLS_ASN1_WRITE_C */

Coverage Report

Created: 2024-01-20 12:33

Line	Count	Source (jump to first uncovered line)
1		/*
2		* ASN.1 buffer writing functionality
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_ASN1_WRITE_C)
23
24		#include "mbedtls/asn1write.h"
25		#include "mbedtls/error.h"
26
27		#include <string.h>
28
29		#include "mbedtls/platform.h"
30
31		int mbedtls_asn1_write_len(unsigned char *p, const unsigned char start, size_t len)
32	0	{
33	0	if (len < 0x80) {
34	0	if (*p - start < 1) {
35	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
36	0	}
37
38	0	--(p) = (unsigned char) len;
39	0	return 1;
40	0	}
41
42	0	if (len <= 0xFF) {
43	0	if (*p - start < 2) {
44	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
45	0	}
46
47	0	--(p) = (unsigned char) len;
48	0	--(p) = 0x81;
49	0	return 2;
50	0	}
51
52	0	if (len <= 0xFFFF) {
53	0	if (*p - start < 3) {
54	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
55	0	}
56
57	0	--(p) = MBEDTLS_BYTE_0(len);
58	0	--(p) = MBEDTLS_BYTE_1(len);
59	0	--(p) = 0x82;
60	0	return 3;
61	0	}
62
63	0	if (len <= 0xFFFFFF) {
64	0	if (*p - start < 4) {
65	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
66	0	}
67
68	0	--(p) = MBEDTLS_BYTE_0(len);
69	0	--(p) = MBEDTLS_BYTE_1(len);
70	0	--(p) = MBEDTLS_BYTE_2(len);
71	0	--(p) = 0x83;
72	0	return 4;
73	0	}
74
75	0	int len_is_valid = 1;
76	0	#if SIZE_MAX > 0xFFFFFFFF
77	0	len_is_valid = (len <= 0xFFFFFFFF);
78	0	#endif
79	0	if (len_is_valid) {
80	0	if (*p - start < 5) {
81	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
82	0	}
83
84	0	--(p) = MBEDTLS_BYTE_0(len);
85	0	--(p) = MBEDTLS_BYTE_1(len);
86	0	--(p) = MBEDTLS_BYTE_2(len);
87	0	--(p) = MBEDTLS_BYTE_3(len);
88	0	--(p) = 0x84;
89	0	return 5;
90	0	}
91
92	0	return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
93	0	}
94
95		int mbedtls_asn1_write_tag(unsigned char *p, const unsigned char start, unsigned char tag)
96	0	{
97	0	if (*p - start < 1) {
98	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
99	0	}
100
101	0	--(p) = tag;
102
103	0	return 1;
104	0	}
105
106		int mbedtls_asn1_write_raw_buffer(unsigned char *p, const unsigned char start,
107		const unsigned char *buf, size_t size)
108	0	{
109	0	size_t len = 0;
110
111	0	if (p < start \|\| (size_t) (p - start) < size) {
112	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
113	0	}
114
115	0	len = size;
116	0	(*p) -= len;
117	0	memcpy(*p, buf, len);
118
119	0	return (int) len;
120	0	}
121
122		#if defined(MBEDTLS_BIGNUM_C)
123		int mbedtls_asn1_write_mpi(unsigned char *p, const unsigned char start, const mbedtls_mpi *X)
124	0	{
125	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
126	0	size_t len = 0;
127
128		// Write the MPI
129		//
130	0	len = mbedtls_mpi_size(X);
131
132		/* DER represents 0 with a sign bit (0=nonnegative) and 7 value bits, not
133		* as 0 digits. We need to end up with 020100, not with 0200. */
134	0	if (len == 0) {
135	0	len = 1;
136	0	}
137
138	0	if (p < start \|\| (size_t) (p - start) < len) {
139	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
140	0	}
141
142	0	(*p) -= len;
143	0	MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(X, *p, len));
144
145		// DER format assumes 2s complement for numbers, so the leftmost bit
146		// should be 0 for positive numbers and 1 for negative numbers.
147		//
148	0	if (X->s == 1 && **p & 0x80) {
149	0	if (*p - start < 1) {
150	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
151	0	}
152
153	0	--(p) = 0x00;
154	0	len += 1;
155	0	}
156
157	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
158	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_INTEGER));
159
160	0	ret = (int) len;
161
162	0	cleanup:
163	0	return ret;
164	0	}
165		#endif /* MBEDTLS_BIGNUM_C */
166
167		int mbedtls_asn1_write_null(unsigned char *p, const unsigned char start)
168	0	{
169	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
170	0	size_t len = 0;
171
172		// Write NULL
173		//
174	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, 0));
175	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_NULL));
176
177	0	return (int) len;
178	0	}
179
180		int mbedtls_asn1_write_oid(unsigned char *p, const unsigned char start,
181		const char *oid, size_t oid_len)
182	0	{
183	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
184	0	size_t len = 0;
185
186	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
187	0	(const unsigned char *) oid, oid_len));
188	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
189	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID));
190
191	0	return (int) len;
192	0	}
193
194		int mbedtls_asn1_write_algorithm_identifier(unsigned char *p, const unsigned char start,
195		const char *oid, size_t oid_len,
196		size_t par_len)
197	0	{
198	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
199	0	size_t len = 0;
200
201	0	if (par_len == 0) {
202	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_null(p, start));
203	0	} else {
204	0	len += par_len;
205	0	}
206
207	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid, oid_len));
208
209	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
210	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
211	0	MBEDTLS_ASN1_CONSTRUCTED \|
212	0	MBEDTLS_ASN1_SEQUENCE));
213
214	0	return (int) len;
215	0	}
216
217		int mbedtls_asn1_write_bool(unsigned char *p, const unsigned char start, int boolean)
218	0	{
219	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
220	0	size_t len = 0;
221
222	0	if (*p - start < 1) {
223	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
224	0	}
225
226	0	--(p) = (boolean) ? 255 : 0;
227	0	len++;
228
229	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
230	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BOOLEAN));
231
232	0	return (int) len;
233	0	}
234
235		static int asn1_write_tagged_int(unsigned char *p, const unsigned char start, int val, int tag)
236	0	{
237	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
238	0	size_t len = 0;
239
240	0	do {
241	0	if (*p - start < 1) {
242	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
243	0	}
244	0	len += 1;
245	0	--(p) = val & 0xff;
246	0	val >>= 8;
247	0	} while (val > 0);
248
249	0	if (**p & 0x80) {
250	0	if (*p - start < 1) {
251	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
252	0	}
253	0	--(p) = 0x00;
254	0	len += 1;
255	0	}
256
257	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
258	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));
259
260	0	return (int) len;
261	0	}
262
263		int mbedtls_asn1_write_int(unsigned char *p, const unsigned char start, int val)
264	0	{
265	0	return asn1_write_tagged_int(p, start, val, MBEDTLS_ASN1_INTEGER);
266	0	}
267
268		int mbedtls_asn1_write_enum(unsigned char *p, const unsigned char start, int val)
269	0	{
270	0	return asn1_write_tagged_int(p, start, val, MBEDTLS_ASN1_ENUMERATED);
271	0	}
272
273		int mbedtls_asn1_write_tagged_string(unsigned char *p, const unsigned char start, int tag,
274		const char *text, size_t text_len)
275	0	{
276	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
277	0	size_t len = 0;
278
279	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
280	0	(const unsigned char *) text,
281	0	text_len));
282
283	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
284	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));
285
286	0	return (int) len;
287	0	}
288
289		int mbedtls_asn1_write_utf8_string(unsigned char *p, const unsigned char start,
290		const char *text, size_t text_len)
291	0	{
292	0	return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len);
293	0	}
294
295		int mbedtls_asn1_write_printable_string(unsigned char *p, const unsigned char start,
296		const char *text, size_t text_len)
297	0	{
298	0	return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text,
299	0	text_len);
300	0	}
301
302		int mbedtls_asn1_write_ia5_string(unsigned char *p, const unsigned char start,
303		const char *text, size_t text_len)
304	0	{
305	0	return mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len);
306	0	}
307
308		int mbedtls_asn1_write_named_bitstring(unsigned char **p,
309		const unsigned char *start,
310		const unsigned char *buf,
311		size_t bits)
312	0	{
313	0	size_t unused_bits, byte_len;
314	0	const unsigned char *cur_byte;
315	0	unsigned char cur_byte_shifted;
316	0	unsigned char bit;
317
318	0	byte_len = (bits + 7) / 8;
319	0	unused_bits = (byte_len * 8) - bits;
320
321		/*
322		* Named bitstrings require that trailing 0s are excluded in the encoding
323		* of the bitstring. Trailing 0s are considered part of the 'unused' bits
324		* when encoding this value in the first content octet
325		*/
326	0	if (bits != 0) {
327	0	cur_byte = buf + byte_len - 1;
328	0	cur_byte_shifted = *cur_byte >> unused_bits;
329
330	0	for (;;) {
331	0	bit = cur_byte_shifted & 0x1;
332	0	cur_byte_shifted >>= 1;
333
334	0	if (bit != 0) {
335	0	break;
336	0	}
337
338	0	bits--;
339	0	if (bits == 0) {
340	0	break;
341	0	}
342
343	0	if (bits % 8 == 0) {
344	0	cur_byte_shifted = *--cur_byte;
345	0	}
346	0	}
347	0	}
348
349	0	return mbedtls_asn1_write_bitstring(p, start, buf, bits);
350	0	}
351
352		int mbedtls_asn1_write_bitstring(unsigned char *p, const unsigned char start,
353		const unsigned char *buf, size_t bits)
354	0	{
355	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
356	0	size_t len = 0;
357	0	size_t unused_bits, byte_len;
358
359	0	byte_len = (bits + 7) / 8;
360	0	unused_bits = (byte_len * 8) - bits;
361
362	0	if (p < start \|\| (size_t) (p - start) < byte_len + 1) {
363	0	return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
364	0	}
365
366	0	len = byte_len + 1;
367
368		/* Write the bitstring. Ensure the unused bits are zeroed */
369	0	if (byte_len > 0) {
370	0	byte_len--;
371	0	--(p) = buf[byte_len] & ~((0x1 << unused_bits) - 1);
372	0	(*p) -= byte_len;
373	0	memcpy(*p, buf, byte_len);
374	0	}
375
376		/* Write unused bits */
377	0	--(p) = (unsigned char) unused_bits;
378
379	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
380	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING));
381
382	0	return (int) len;
383	0	}
384
385		int mbedtls_asn1_write_octet_string(unsigned char *p, const unsigned char start,
386		const unsigned char *buf, size_t size)
387	0	{
388	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
389	0	size_t len = 0;
390
391	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, buf, size));
392
393	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
394	0	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING));
395
396	0	return (int) len;
397	0	}
398
399
400		/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
401		* which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
402		static mbedtls_asn1_named_data *asn1_find_named_data(
403		mbedtls_asn1_named_data *list,
404		const char *oid, size_t len)
405	0	{
406	0	while (list != NULL) {
407	0	if (list->oid.len == len &&
408	0	memcmp(list->oid.p, oid, len) == 0) {
409	0	break;
410	0	}
411
412	0	list = list->next;
413	0	}
414
415	0	return list;
416	0	}
417
418		mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
419		mbedtls_asn1_named_data **head,
420		const char *oid, size_t oid_len,
421		const unsigned char *val,
422		size_t val_len)
423	0	{
424	0	mbedtls_asn1_named_data *cur;
425
426	0	if ((cur = asn1_find_named_data(*head, oid, oid_len)) == NULL) {
427		// Add new entry if not present yet based on OID
428		//
429	0	cur = (mbedtls_asn1_named_data *) mbedtls_calloc(1,
430	0	sizeof(mbedtls_asn1_named_data));
431	0	if (cur == NULL) {
432	0	return NULL;
433	0	}
434
435	0	cur->oid.len = oid_len;
436	0	cur->oid.p = mbedtls_calloc(1, oid_len);
437	0	if (cur->oid.p == NULL) {
438	0	mbedtls_free(cur);
439	0	return NULL;
440	0	}
441
442	0	memcpy(cur->oid.p, oid, oid_len);
443
444	0	cur->val.len = val_len;
445	0	if (val_len != 0) {
446	0	cur->val.p = mbedtls_calloc(1, val_len);
447	0	if (cur->val.p == NULL) {
448	0	mbedtls_free(cur->oid.p);
449	0	mbedtls_free(cur);
450	0	return NULL;
451	0	}
452	0	}
453
454	0	cur->next = *head;
455	0	*head = cur;
456	0	} else if (val_len == 0) {
457	0	mbedtls_free(cur->val.p);
458	0	cur->val.p = NULL;
459	0	} else if (cur->val.len != val_len) {
460		/*
461		* Enlarge existing value buffer if needed
462		* Preserve old data until the allocation succeeded, to leave list in
463		* a consistent state in case allocation fails.
464		*/
465	0	void *p = mbedtls_calloc(1, val_len);
466	0	if (p == NULL) {
467	0	return NULL;
468	0	}
469
470	0	mbedtls_free(cur->val.p);
471	0	cur->val.p = p;
472	0	cur->val.len = val_len;
473	0	}
474
475	0	if (val != NULL && val_len != 0) {
476	0	memcpy(cur->val.p, val, val_len);
477	0	}
478
479	0	return cur;
480	0	}
481		#endif /* MBEDTLS_ASN1_WRITE_C */