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djm@openbsd.org7be85722019-01-21 09:54:11 +00001/* $OpenBSD: sshbuf-getput-crypto.c,v 1.7 2019/01/21 09:54:11 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
djm@openbsd.org7be85722019-01-21 09:54:11 +000035sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp)
Damien Miller05e82c32014-05-15 14:33:43 +100036{
djm@openbsd.org7be85722019-01-21 09:54:11 +000037 BIGNUM *v;
Damien Miller05e82c32014-05-15 14:33:43 +100038 const u_char *d;
39 size_t len;
40 int r;
41
djm@openbsd.org7be85722019-01-21 09:54:11 +000042 if (valp != NULL)
43 *valp = NULL;
djm@openbsd.orga165bab2015-01-14 15:02:39 +000044 if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
Damien Miller05e82c32014-05-15 14:33:43 +100045 return r;
djm@openbsd.org7be85722019-01-21 09:54:11 +000046 if (valp != NULL) {
47 if ((v = BN_new()) == NULL ||
48 BN_bin2bn(d, len, v) == NULL) {
49 BN_clear_free(v);
50 return SSH_ERR_ALLOC_FAIL;
51 }
52 *valp = v;
53 }
Damien Miller05e82c32014-05-15 14:33:43 +100054 return 0;
55}
56
Damien Miller05e82c32014-05-15 14:33:43 +100057#ifdef OPENSSL_HAS_ECC
58static int
59get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
60{
61 /* Refuse overlong bignums */
62 if (len == 0 || len > SSHBUF_MAX_ECPOINT)
63 return SSH_ERR_ECPOINT_TOO_LARGE;
64 /* Only handle uncompressed points */
65 if (*d != POINT_CONVERSION_UNCOMPRESSED)
66 return SSH_ERR_INVALID_FORMAT;
67 if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
68 return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
69 return 0;
70}
71
72int
73sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
74{
75 const u_char *d;
76 size_t len;
77 int r;
78
79 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
80 return r;
81 if ((r = get_ec(d, len, v, g)) != 0)
82 return r;
83 /* Skip string */
84 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
85 /* Shouldn't happen */
86 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
87 SSHBUF_ABORT();
88 return SSH_ERR_INTERNAL_ERROR;
89 }
90 return 0;
91}
92
93int
94sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
95{
96 EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
97 int r;
98 const u_char *d;
99 size_t len;
100
101 if (pt == NULL) {
102 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
103 return SSH_ERR_ALLOC_FAIL;
104 }
105 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
106 EC_POINT_free(pt);
107 return r;
108 }
109 if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
110 EC_POINT_free(pt);
111 return r;
112 }
113 if (EC_KEY_set_public_key(v, pt) != 1) {
114 EC_POINT_free(pt);
115 return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
116 }
117 EC_POINT_free(pt);
118 /* Skip string */
119 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
120 /* Shouldn't happen */
121 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
122 SSHBUF_ABORT();
123 return SSH_ERR_INTERNAL_ERROR;
124 }
125 return 0;
126}
127#endif /* OPENSSL_HAS_ECC */
128
129int
130sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
131{
132 u_char d[SSHBUF_MAX_BIGNUM + 1];
133 int len = BN_num_bytes(v), prepend = 0, r;
134
135 if (len < 0 || len > SSHBUF_MAX_BIGNUM)
136 return SSH_ERR_INVALID_ARGUMENT;
137 *d = '\0';
138 if (BN_bn2bin(v, d + 1) != len)
139 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
140 /* If MSB is set, prepend a \0 */
141 if (len > 0 && (d[1] & 0x80) != 0)
142 prepend = 1;
143 if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
djm@openbsd.org9a728cc2016-01-12 23:42:54 +0000144 explicit_bzero(d, sizeof(d));
Damien Miller05e82c32014-05-15 14:33:43 +1000145 return r;
146 }
djm@openbsd.org9a728cc2016-01-12 23:42:54 +0000147 explicit_bzero(d, sizeof(d));
Damien Miller05e82c32014-05-15 14:33:43 +1000148 return 0;
149}
150
Damien Miller05e82c32014-05-15 14:33:43 +1000151#ifdef OPENSSL_HAS_ECC
152int
153sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
154{
155 u_char d[SSHBUF_MAX_ECPOINT];
156 BN_CTX *bn_ctx;
157 size_t len;
158 int ret;
159
160 if ((bn_ctx = BN_CTX_new()) == NULL)
161 return SSH_ERR_ALLOC_FAIL;
162 if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
163 NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
164 BN_CTX_free(bn_ctx);
165 return SSH_ERR_INVALID_ARGUMENT;
166 }
167 if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
168 d, len, bn_ctx) != len) {
169 BN_CTX_free(bn_ctx);
170 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
171 }
172 BN_CTX_free(bn_ctx);
173 ret = sshbuf_put_string(buf, d, len);
djm@openbsd.org9a728cc2016-01-12 23:42:54 +0000174 explicit_bzero(d, len);
Damien Miller05e82c32014-05-15 14:33:43 +1000175 return ret;
176}
177
178int
179sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
180{
181 return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
182 EC_KEY_get0_group(v));
183}
184#endif /* OPENSSL_HAS_ECC */
185