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djm@openbsd.orga165bab2015-01-14 15:02:39 +00001/* $OpenBSD: sshbuf-getput-crypto.c,v 1.4 2015/01/14 15:02:39 djm Exp $ */
Damien Miller05e82c32014-05-15 14:33:43 +10002/*
3 * Copyright (c) 2011 Damien Miller
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
Damien Millere5b9f0f2014-05-15 14:58:07 +100018#define SSHBUF_INTERNAL
Damien Miller05e82c32014-05-15 14:33:43 +100019#include "includes.h"
20
21#include <sys/types.h>
22#include <stdlib.h>
23#include <stdio.h>
24#include <string.h>
25
26#include <openssl/bn.h>
Damien Miller0c11f1a2014-08-22 17:36:56 +100027#ifdef OPENSSL_HAS_ECC
28# include <openssl/ec.h>
29#endif /* OPENSSL_HAS_ECC */
Damien Miller05e82c32014-05-15 14:33:43 +100030
31#include "ssherr.h"
Damien Miller05e82c32014-05-15 14:33:43 +100032#include "sshbuf.h"
33
34int
35sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v)
36{
37 const u_char *d;
38 size_t len;
39 int r;
40
djm@openbsd.orga165bab2015-01-14 15:02:39 +000041 if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
Damien Miller05e82c32014-05-15 14:33:43 +100042 return r;
Damien Miller05e82c32014-05-15 14:33:43 +100043 if (v != NULL && BN_bin2bn(d, len, v) == NULL)
44 return SSH_ERR_ALLOC_FAIL;
Damien Miller05e82c32014-05-15 14:33:43 +100045 return 0;
46}
47
48int
49sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v)
50{
51 const u_char *d = sshbuf_ptr(buf);
52 u_int16_t len_bits;
53 size_t len_bytes;
54
55 /* Length in bits */
56 if (sshbuf_len(buf) < 2)
57 return SSH_ERR_MESSAGE_INCOMPLETE;
58 len_bits = PEEK_U16(d);
59 len_bytes = (len_bits + 7) >> 3;
Damien Miller99db8402014-07-02 12:48:04 +100060 if (len_bytes > SSHBUF_MAX_BIGNUM)
Damien Miller05e82c32014-05-15 14:33:43 +100061 return SSH_ERR_BIGNUM_TOO_LARGE;
62 if (sshbuf_len(buf) < 2 + len_bytes)
63 return SSH_ERR_MESSAGE_INCOMPLETE;
64 if (v != NULL && BN_bin2bn(d + 2, len_bytes, v) == NULL)
65 return SSH_ERR_ALLOC_FAIL;
66 if (sshbuf_consume(buf, 2 + len_bytes) != 0) {
67 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
68 SSHBUF_ABORT();
69 return SSH_ERR_INTERNAL_ERROR;
70 }
71 return 0;
72}
73
74#ifdef OPENSSL_HAS_ECC
75static int
76get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
77{
78 /* Refuse overlong bignums */
79 if (len == 0 || len > SSHBUF_MAX_ECPOINT)
80 return SSH_ERR_ECPOINT_TOO_LARGE;
81 /* Only handle uncompressed points */
82 if (*d != POINT_CONVERSION_UNCOMPRESSED)
83 return SSH_ERR_INVALID_FORMAT;
84 if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
85 return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
86 return 0;
87}
88
89int
90sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
91{
92 const u_char *d;
93 size_t len;
94 int r;
95
96 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
97 return r;
98 if ((r = get_ec(d, len, v, g)) != 0)
99 return r;
100 /* Skip string */
101 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
102 /* Shouldn't happen */
103 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
104 SSHBUF_ABORT();
105 return SSH_ERR_INTERNAL_ERROR;
106 }
107 return 0;
108}
109
110int
111sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
112{
113 EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
114 int r;
115 const u_char *d;
116 size_t len;
117
118 if (pt == NULL) {
119 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
120 return SSH_ERR_ALLOC_FAIL;
121 }
122 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
123 EC_POINT_free(pt);
124 return r;
125 }
126 if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
127 EC_POINT_free(pt);
128 return r;
129 }
130 if (EC_KEY_set_public_key(v, pt) != 1) {
131 EC_POINT_free(pt);
132 return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
133 }
134 EC_POINT_free(pt);
135 /* Skip string */
136 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
137 /* Shouldn't happen */
138 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
139 SSHBUF_ABORT();
140 return SSH_ERR_INTERNAL_ERROR;
141 }
142 return 0;
143}
144#endif /* OPENSSL_HAS_ECC */
145
146int
147sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
148{
149 u_char d[SSHBUF_MAX_BIGNUM + 1];
150 int len = BN_num_bytes(v), prepend = 0, r;
151
152 if (len < 0 || len > SSHBUF_MAX_BIGNUM)
153 return SSH_ERR_INVALID_ARGUMENT;
154 *d = '\0';
155 if (BN_bn2bin(v, d + 1) != len)
156 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
157 /* If MSB is set, prepend a \0 */
158 if (len > 0 && (d[1] & 0x80) != 0)
159 prepend = 1;
160 if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
161 bzero(d, sizeof(d));
162 return r;
163 }
164 bzero(d, sizeof(d));
165 return 0;
166}
167
168int
169sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v)
170{
171 int r, len_bits = BN_num_bits(v);
172 size_t len_bytes = (len_bits + 7) / 8;
173 u_char d[SSHBUF_MAX_BIGNUM], *dp;
174
175 if (len_bits < 0 || len_bytes > SSHBUF_MAX_BIGNUM)
176 return SSH_ERR_INVALID_ARGUMENT;
177 if (BN_bn2bin(v, d) != (int)len_bytes)
178 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
179 if ((r = sshbuf_reserve(buf, len_bytes + 2, &dp)) < 0) {
180 bzero(d, sizeof(d));
181 return r;
182 }
183 POKE_U16(dp, len_bits);
djm@openbsd.orga7f49dc2015-01-12 15:18:07 +0000184 if (len_bytes != 0)
185 memcpy(dp + 2, d, len_bytes);
Damien Miller05e82c32014-05-15 14:33:43 +1000186 bzero(d, sizeof(d));
187 return 0;
188}
189
190#ifdef OPENSSL_HAS_ECC
191int
192sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
193{
194 u_char d[SSHBUF_MAX_ECPOINT];
195 BN_CTX *bn_ctx;
196 size_t len;
197 int ret;
198
199 if ((bn_ctx = BN_CTX_new()) == NULL)
200 return SSH_ERR_ALLOC_FAIL;
201 if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
202 NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
203 BN_CTX_free(bn_ctx);
204 return SSH_ERR_INVALID_ARGUMENT;
205 }
206 if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
207 d, len, bn_ctx) != len) {
208 BN_CTX_free(bn_ctx);
209 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
210 }
211 BN_CTX_free(bn_ctx);
212 ret = sshbuf_put_string(buf, d, len);
213 bzero(d, len);
214 return ret;
215}
216
217int
218sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
219{
220 return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
221 EC_KEY_get0_group(v));
222}
223#endif /* OPENSSL_HAS_ECC */
224