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1/* $OpenBSD: sshbuf-getput-crypto.c,v 1.12 2024/08/15 00:51:51 djm Exp $ */
2/*
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
18#include <sys/types.h>
19#include <stdlib.h>
20#include <stdio.h>
21#include <string.h>
22
23#include <openssl/bn.h>
24#include <openssl/ec.h>
25
26#include "ssherr.h"
27#define SSHBUF_INTERNAL
28#include "sshbuf.h"
29
30int
31sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp)
32{
33 BIGNUM *v;
34 const u_char *d;
35 size_t len;
36 int r;
37
38 if (valp != NULL)
39 *valp = NULL;
40 if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
41 return r;
42 if (valp != NULL) {
43 if ((v = BN_new()) == NULL ||
44 BN_bin2bn(d, len, v) == NULL) {
45 BN_clear_free(v);
46 return SSH_ERR_ALLOC_FAIL;
47 }
48 *valp = v;
49 }
50 return 0;
51}
52
53static int
54get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
55{
56 /* Refuse overlong bignums */
57 if (len == 0 || len > SSHBUF_MAX_ECPOINT)
58 return SSH_ERR_ECPOINT_TOO_LARGE;
59 /* Only handle uncompressed points */
60 if (*d != POINT_CONVERSION_UNCOMPRESSED)
61 return SSH_ERR_INVALID_FORMAT;
62 if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
63 return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
64 return 0;
65}
66
67int
68sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
69{
70 const u_char *d;
71 size_t len;
72 int r;
73
74 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
75 return r;
76 if ((r = get_ec(d, len, v, g)) != 0)
77 return r;
78 /* Skip string */
79 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
80 /* Shouldn't happen */
81 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
82 SSHBUF_ABORT();
83 return SSH_ERR_INTERNAL_ERROR;
84 }
85 return 0;
86}
87
88int
89sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
90{
91 EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
92 int r;
93 const u_char *d;
94 size_t len;
95
96 if (pt == NULL) {
97 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
98 return SSH_ERR_ALLOC_FAIL;
99 }
100 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
101 EC_POINT_free(pt);
102 return r;
103 }
104 if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
105 EC_POINT_free(pt);
106 return r;
107 }
108 if (EC_KEY_set_public_key(v, pt) != 1) {
109 EC_POINT_free(pt);
110 return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
111 }
112 EC_POINT_free(pt);
113 /* Skip string */
114 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
115 /* Shouldn't happen */
116 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
117 SSHBUF_ABORT();
118 return SSH_ERR_INTERNAL_ERROR;
119 }
120 return 0;
121}
122
123int
124sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
125{
126 u_char d[SSHBUF_MAX_BIGNUM + 1];
127 int len = BN_num_bytes(v), prepend = 0, r;
128
129 if (len < 0 || len > SSHBUF_MAX_BIGNUM)
130 return SSH_ERR_INVALID_ARGUMENT;
131 *d = '\0';
132 if (BN_bn2bin(v, d + 1) != len)
133 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
134 /* If MSB is set, prepend a \0 */
135 if (len > 0 && (d[1] & 0x80) != 0)
136 prepend = 1;
137 if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
138 explicit_bzero(d, sizeof(d));
139 return r;
140 }
141 explicit_bzero(d, sizeof(d));
142 return 0;
143}
144
145int
146sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
147{
148 u_char d[SSHBUF_MAX_ECPOINT];
149 size_t len;
150 int ret;
151
152 if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
153 NULL, 0, NULL)) > SSHBUF_MAX_ECPOINT) {
154 return SSH_ERR_INVALID_ARGUMENT;
155 }
156 if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
157 d, len, NULL) != len) {
158 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
159 }
160 ret = sshbuf_put_string(buf, d, len);
161 explicit_bzero(d, len);
162 return ret;
163}
164
165int
166sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
167{
168 return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
169 EC_KEY_get0_group(v));
170}
171
172int
173sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey)
174{
175 const EC_KEY *ec;
176
177 if ((ec = EVP_PKEY_get0_EC_KEY(pkey)) == NULL)
178 return SSH_ERR_LIBCRYPTO_ERROR;
179 return sshbuf_put_eckey(buf, ec);
180}