1 /* $OpenBSD: sshbuf-getput-crypto.c,v 1.7 2019/01/21 09:54:11 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 #include <openssl/bn.h> 27 #ifdef OPENSSL_HAS_ECC 28 # include <openssl/ec.h> 29 #endif /* OPENSSL_HAS_ECC */ 30 31 #include "ssherr.h" 32 #include "sshbuf.h" 33 34 int 35 sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp) 36 { 37 BIGNUM *v; 38 const u_char *d; 39 size_t len; 40 int r; 41 42 if (valp != NULL) 43 *valp = NULL; 44 if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0) 45 return r; 46 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 } 54 return 0; 55 } 56 57 #ifdef OPENSSL_HAS_ECC 58 static int 59 get_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 72 int 73 sshbuf_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 93 int 94 sshbuf_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 */ 128 129 int 130 sshbuf_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) { 144 explicit_bzero(d, sizeof(d)); 145 return r; 146 } 147 explicit_bzero(d, sizeof(d)); 148 return 0; 149 } 150 151 #ifdef OPENSSL_HAS_ECC 152 int 153 sshbuf_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); 174 explicit_bzero(d, len); 175 return ret; 176 } 177 178 int 179 sshbuf_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 */ 185 186