xref: /freebsd/contrib/bearssl/src/x509/encode_rsa_rawder.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
1 /*
2  * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining
5  * a copy of this software and associated documentation files (the
6  * "Software"), to deal in the Software without restriction, including
7  * without limitation the rights to use, copy, modify, merge, publish,
8  * distribute, sublicense, and/or sell copies of the Software, and to
9  * permit persons to whom the Software is furnished to do so, subject to
10  * the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be
13  * included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  * SOFTWARE.
23  */
24 
25 #include "inner.h"
26 
27 /* see bearssl_x509.h */
28 size_t
29 br_encode_rsa_raw_der(void *dest, const br_rsa_private_key *sk,
30 	const br_rsa_public_key *pk, const void *d, size_t dlen)
31 {
32 	/*
33 	 * ASN.1 format:
34 	 *
35 	 *   RSAPrivateKey ::= SEQUENCE {
36 	 *       version           Version,
37 	 *       modulus           INTEGER,  -- n
38 	 *       publicExponent    INTEGER,  -- e
39 	 *       privateExponent   INTEGER,  -- d
40 	 *       prime1            INTEGER,  -- p
41 	 *       prime2            INTEGER,  -- q
42 	 *       exponent1         INTEGER,  -- d mod (p-1)
43 	 *       exponent2         INTEGER,  -- d mod (q-1)
44 	 *       coefficient       INTEGER,  -- (inverse of q) mod p
45 	 *       otherPrimeInfos   OtherPrimeInfos OPTIONAL
46 	 *   }
47 	 *
48 	 * The 'version' field is an INTEGER of value 0 (meaning: there
49 	 * are exactly two prime factors), and 'otherPrimeInfos' will
50 	 * be absent (because there are exactly two prime factors).
51 	 */
52 
53 	br_asn1_uint num[9];
54 	size_t u, slen;
55 
56 	/*
57 	 * For all INTEGER values, get the pointer and length for the
58 	 * data bytes.
59 	 */
60 	num[0] = br_asn1_uint_prepare(NULL, 0);
61 	num[1] = br_asn1_uint_prepare(pk->n, pk->nlen);
62 	num[2] = br_asn1_uint_prepare(pk->e, pk->elen);
63 	num[3] = br_asn1_uint_prepare(d, dlen);
64 	num[4] = br_asn1_uint_prepare(sk->p, sk->plen);
65 	num[5] = br_asn1_uint_prepare(sk->q, sk->qlen);
66 	num[6] = br_asn1_uint_prepare(sk->dp, sk->dplen);
67 	num[7] = br_asn1_uint_prepare(sk->dq, sk->dqlen);
68 	num[8] = br_asn1_uint_prepare(sk->iq, sk->iqlen);
69 
70 	/*
71 	 * Get the length of the SEQUENCE contents.
72 	 */
73 	slen = 0;
74 	for (u = 0; u < 9; u ++) {
75 		uint32_t ilen;
76 
77 		ilen = num[u].asn1len;
78 		slen += 1 + len_of_len(ilen) + ilen;
79 	}
80 
81 	if (dest == NULL) {
82 		return 1 + len_of_len(slen) + slen;
83 	} else {
84 		unsigned char *buf;
85 		size_t lenlen;
86 
87 		buf = dest;
88 		*buf ++ = 0x30;  /* SEQUENCE tag */
89 		lenlen = br_asn1_encode_length(buf, slen);
90 		buf += lenlen;
91 		for (u = 0; u < 9; u ++) {
92 			buf += br_asn1_encode_uint(buf, num[u]);
93 		}
94 		return 1 + lenlen + slen;
95 	}
96 }
97