1 /* $OpenBSD: sshbuf-getput-crypto.c,v 1.10 2022/05/25 06:03:44 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 #define SSHBUF_INTERNAL 19 #include "includes.h" 20 21 #include <sys/types.h> 22 #include <stdlib.h> 23 #include <stdio.h> 24 #include <string.h> 25 26 #ifdef WITH_OPENSSL 27 #include <openssl/bn.h> 28 #ifdef OPENSSL_HAS_ECC 29 # include <openssl/ec.h> 30 #endif /* OPENSSL_HAS_ECC */ 31 32 #include "ssherr.h" 33 #include "sshbuf.h" 34 35 int 36 sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp) 37 { 38 BIGNUM *v; 39 const u_char *d; 40 size_t len; 41 int r; 42 43 if (valp != NULL) 44 *valp = NULL; 45 if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0) 46 return r; 47 if (valp != NULL) { 48 if ((v = BN_new()) == NULL || 49 BN_bin2bn(d, len, v) == NULL) { 50 BN_clear_free(v); 51 return SSH_ERR_ALLOC_FAIL; 52 } 53 *valp = v; 54 } 55 return 0; 56 } 57 58 #ifdef OPENSSL_HAS_ECC 59 static int 60 get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g) 61 { 62 /* Refuse overlong bignums */ 63 if (len == 0 || len > SSHBUF_MAX_ECPOINT) 64 return SSH_ERR_ECPOINT_TOO_LARGE; 65 /* Only handle uncompressed points */ 66 if (*d != POINT_CONVERSION_UNCOMPRESSED) 67 return SSH_ERR_INVALID_FORMAT; 68 if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1) 69 return SSH_ERR_INVALID_FORMAT; /* XXX assumption */ 70 return 0; 71 } 72 73 int 74 sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g) 75 { 76 const u_char *d; 77 size_t len; 78 int r; 79 80 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) 81 return r; 82 if ((r = get_ec(d, len, v, g)) != 0) 83 return r; 84 /* Skip string */ 85 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) { 86 /* Shouldn't happen */ 87 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 88 SSHBUF_ABORT(); 89 return SSH_ERR_INTERNAL_ERROR; 90 } 91 return 0; 92 } 93 94 int 95 sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v) 96 { 97 EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v)); 98 int r; 99 const u_char *d; 100 size_t len; 101 102 if (pt == NULL) { 103 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); 104 return SSH_ERR_ALLOC_FAIL; 105 } 106 if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) { 107 EC_POINT_free(pt); 108 return r; 109 } 110 if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) { 111 EC_POINT_free(pt); 112 return r; 113 } 114 if (EC_KEY_set_public_key(v, pt) != 1) { 115 EC_POINT_free(pt); 116 return SSH_ERR_ALLOC_FAIL; /* XXX assumption */ 117 } 118 EC_POINT_free(pt); 119 /* Skip string */ 120 if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) { 121 /* Shouldn't happen */ 122 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 123 SSHBUF_ABORT(); 124 return SSH_ERR_INTERNAL_ERROR; 125 } 126 return 0; 127 } 128 #endif /* OPENSSL_HAS_ECC */ 129 130 int 131 sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v) 132 { 133 u_char d[SSHBUF_MAX_BIGNUM + 1]; 134 int len = BN_num_bytes(v), prepend = 0, r; 135 136 if (len < 0 || len > SSHBUF_MAX_BIGNUM) 137 return SSH_ERR_INVALID_ARGUMENT; 138 *d = '\0'; 139 if (BN_bn2bin(v, d + 1) != len) 140 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */ 141 /* If MSB is set, prepend a \0 */ 142 if (len > 0 && (d[1] & 0x80) != 0) 143 prepend = 1; 144 if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) { 145 explicit_bzero(d, sizeof(d)); 146 return r; 147 } 148 explicit_bzero(d, sizeof(d)); 149 return 0; 150 } 151 152 #ifdef OPENSSL_HAS_ECC 153 int 154 sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g) 155 { 156 u_char d[SSHBUF_MAX_ECPOINT]; 157 size_t len; 158 int ret; 159 160 if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED, 161 NULL, 0, NULL)) > SSHBUF_MAX_ECPOINT) { 162 return SSH_ERR_INVALID_ARGUMENT; 163 } 164 if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED, 165 d, len, NULL) != len) { 166 return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */ 167 } 168 ret = sshbuf_put_string(buf, d, len); 169 explicit_bzero(d, len); 170 return ret; 171 } 172 173 int 174 sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v) 175 { 176 return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v), 177 EC_KEY_get0_group(v)); 178 } 179 #endif /* OPENSSL_HAS_ECC */ 180 #endif /* WITH_OPENSSL */ 181