2 * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include "internal/cryptlib.h"
13 #include "internal/der.h"
14 #include "crypto/bn.h"
16 static int int_start_context(WPACKET *pkt, int tag)
20 if (!ossl_assert(tag <= 30))
22 return WPACKET_start_sub_packet(pkt);
25 static int int_end_context(WPACKET *pkt, int tag)
28 * If someone set the flag WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH on this
29 * sub-packet and this sub-packet has nothing written to it, the DER length
30 * will not be written, and the total written size will be unchanged before
31 * and after WPACKET_close(). We use size1 and size2 to determine if
32 * anything was written, and only write our tag if it has.
39 if (!ossl_assert(tag <= 30))
42 /* Context specific are normally (?) constructed */
43 tag |= DER_F_CONSTRUCTED | DER_C_CONTEXT;
45 return WPACKET_get_total_written(pkt, &size1)
47 && WPACKET_get_total_written(pkt, &size2)
48 && (size1 == size2 || WPACKET_put_bytes_u8(pkt, tag));
51 int DER_w_precompiled(WPACKET *pkt, int tag,
52 const unsigned char *precompiled, size_t precompiled_n)
54 return int_start_context(pkt, tag)
55 && WPACKET_memcpy(pkt, precompiled, precompiled_n)
56 && int_end_context(pkt, tag);
59 int DER_w_boolean(WPACKET *pkt, int tag, int b)
61 return int_start_context(pkt, tag)
62 && WPACKET_start_sub_packet(pkt)
63 && (!b || WPACKET_put_bytes_u8(pkt, 0xFF))
64 && !WPACKET_close(pkt)
65 && !WPACKET_put_bytes_u8(pkt, DER_P_BOOLEAN)
66 && int_end_context(pkt, tag);
69 int DER_w_octet_string(WPACKET *pkt, int tag,
70 const unsigned char *data, size_t data_n)
72 return int_start_context(pkt, tag)
73 && WPACKET_start_sub_packet(pkt)
74 && WPACKET_memcpy(pkt, data, data_n)
76 && WPACKET_put_bytes_u8(pkt, DER_P_OCTET_STRING)
77 && int_end_context(pkt, tag);
80 int DER_w_octet_string_uint32(WPACKET *pkt, int tag, uint32_t value)
82 unsigned char tmp[4] = { 0, 0, 0, 0 };
83 unsigned char *pbuf = tmp + (sizeof(tmp) - 1);
86 *pbuf-- = (value & 0xFF);
89 return DER_w_octet_string(pkt, tag, tmp, sizeof(tmp));
92 static int int_der_w_integer(WPACKET *pkt, int tag,
93 int (*put_bytes)(WPACKET *pkt, const void *v,
94 unsigned int *top_byte),
97 unsigned int top_byte = 0;
99 return int_start_context(pkt, tag)
100 && WPACKET_start_sub_packet(pkt)
101 && put_bytes(pkt, v, &top_byte)
102 && ((top_byte & 0x80) == 0 || WPACKET_put_bytes_u8(pkt, 0))
103 && WPACKET_close(pkt)
104 && WPACKET_put_bytes_u8(pkt, DER_P_INTEGER)
105 && int_end_context(pkt, tag);
108 static int int_put_bytes_ulong(WPACKET *pkt, const void *v,
109 unsigned int *top_byte)
111 const unsigned long *value = v;
112 unsigned long tmp = *value;
117 *top_byte = (tmp & 0xFF);
123 return WPACKET_put_bytes__(pkt, *value, n);
126 /* For integers, we only support unsigned values for now */
127 int DER_w_ulong(WPACKET *pkt, int tag, unsigned long v)
129 return int_der_w_integer(pkt, tag, int_put_bytes_ulong, &v);
132 static int int_put_bytes_bn(WPACKET *pkt, const void *v,
133 unsigned int *top_byte)
135 unsigned char *p = NULL;
136 size_t n = BN_num_bytes(v);
138 /* The BIGNUM limbs are in LE order */
140 ((bn_get_words(v) [(n - 1) / BN_BYTES]) >> (8 * ((n - 1) % BN_BYTES)))
143 if (!WPACKET_allocate_bytes(pkt, n, &p))
150 int DER_w_bn(WPACKET *pkt, int tag, const BIGNUM *v)
152 if (v == NULL || BN_is_negative(v))
155 return DER_w_ulong(pkt, tag, 0);
157 return int_der_w_integer(pkt, tag, int_put_bytes_bn, v);
160 int DER_w_null(WPACKET *pkt, int tag)
162 return int_start_context(pkt, tag)
163 && WPACKET_start_sub_packet(pkt)
164 && WPACKET_close(pkt)
165 && WPACKET_put_bytes_u8(pkt, DER_P_NULL)
166 && int_end_context(pkt, tag);
169 /* Constructed things need a start and an end */
170 int DER_w_begin_sequence(WPACKET *pkt, int tag)
172 return int_start_context(pkt, tag)
173 && WPACKET_start_sub_packet(pkt);
176 int DER_w_end_sequence(WPACKET *pkt, int tag)
179 * If someone set the flag WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH on this
180 * sub-packet and this sub-packet has nothing written to it, the DER length
181 * will not be written, and the total written size will be unchanged before
182 * and after WPACKET_close(). We use size1 and size2 to determine if
183 * anything was written, and only write our tag if it has.
185 * Because we know that int_end_context() needs to do the same check,
186 * we reproduce this flag if the written length was unchanged, or we will
187 * have an erroneous context tag.
191 return WPACKET_get_total_written(pkt, &size1)
192 && WPACKET_close(pkt)
193 && WPACKET_get_total_written(pkt, &size2)
195 ? WPACKET_set_flags(pkt, WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH)
196 : WPACKET_put_bytes_u8(pkt, DER_F_CONSTRUCTED | DER_P_SEQUENCE))
197 && int_end_context(pkt, tag);