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 #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 30 int 31 sshbuf_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 53 static int 54 get_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 67 int 68 sshbuf_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 88 int 89 sshbuf_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 } 122 123 int 124 sshbuf_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 } 144 145 int 146 sshbuf_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 } 164 165 int 166 sshbuf_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 } 171 172