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9a728cc918
use explicit_bzero() more liberally in the buffer code; ok deraadt Upstream-ID: 0ece37069fd66bc6e4f55eb1321f93df372b65bf
225 lines
5.6 KiB
C
225 lines
5.6 KiB
C
/* $OpenBSD: sshbuf-getput-crypto.c,v 1.5 2016/01/12 23:42:54 djm Exp $ */
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/*
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* Copyright (c) 2011 Damien Miller
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#define SSHBUF_INTERNAL
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#include "includes.h"
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#include <sys/types.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <openssl/bn.h>
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#ifdef OPENSSL_HAS_ECC
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# include <openssl/ec.h>
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#endif /* OPENSSL_HAS_ECC */
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#include "ssherr.h"
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#include "sshbuf.h"
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int
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sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v)
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{
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const u_char *d;
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size_t len;
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int r;
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if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
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return r;
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if (v != NULL && BN_bin2bn(d, len, v) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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return 0;
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}
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int
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sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v)
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{
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const u_char *d = sshbuf_ptr(buf);
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u_int16_t len_bits;
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size_t len_bytes;
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/* Length in bits */
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if (sshbuf_len(buf) < 2)
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return SSH_ERR_MESSAGE_INCOMPLETE;
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len_bits = PEEK_U16(d);
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len_bytes = (len_bits + 7) >> 3;
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if (len_bytes > SSHBUF_MAX_BIGNUM)
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return SSH_ERR_BIGNUM_TOO_LARGE;
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if (sshbuf_len(buf) < 2 + len_bytes)
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return SSH_ERR_MESSAGE_INCOMPLETE;
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if (v != NULL && BN_bin2bn(d + 2, len_bytes, v) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if (sshbuf_consume(buf, 2 + len_bytes) != 0) {
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SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
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SSHBUF_ABORT();
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return SSH_ERR_INTERNAL_ERROR;
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}
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return 0;
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}
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#ifdef OPENSSL_HAS_ECC
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static int
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get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
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{
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/* Refuse overlong bignums */
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if (len == 0 || len > SSHBUF_MAX_ECPOINT)
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return SSH_ERR_ECPOINT_TOO_LARGE;
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/* Only handle uncompressed points */
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if (*d != POINT_CONVERSION_UNCOMPRESSED)
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return SSH_ERR_INVALID_FORMAT;
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if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
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return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
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return 0;
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}
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int
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sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
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{
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const u_char *d;
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size_t len;
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int r;
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if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
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return r;
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if ((r = get_ec(d, len, v, g)) != 0)
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return r;
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/* Skip string */
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if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
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/* Shouldn't happen */
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SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
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SSHBUF_ABORT();
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return SSH_ERR_INTERNAL_ERROR;
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}
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return 0;
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}
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int
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sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
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{
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EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
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int r;
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const u_char *d;
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size_t len;
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if (pt == NULL) {
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SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
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return SSH_ERR_ALLOC_FAIL;
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}
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if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
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EC_POINT_free(pt);
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return r;
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}
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if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
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EC_POINT_free(pt);
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return r;
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}
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if (EC_KEY_set_public_key(v, pt) != 1) {
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EC_POINT_free(pt);
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return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
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}
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EC_POINT_free(pt);
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/* Skip string */
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if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
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/* Shouldn't happen */
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SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
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SSHBUF_ABORT();
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return SSH_ERR_INTERNAL_ERROR;
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}
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return 0;
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}
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#endif /* OPENSSL_HAS_ECC */
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int
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sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
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{
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u_char d[SSHBUF_MAX_BIGNUM + 1];
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int len = BN_num_bytes(v), prepend = 0, r;
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if (len < 0 || len > SSHBUF_MAX_BIGNUM)
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return SSH_ERR_INVALID_ARGUMENT;
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*d = '\0';
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if (BN_bn2bin(v, d + 1) != len)
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return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
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/* If MSB is set, prepend a \0 */
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if (len > 0 && (d[1] & 0x80) != 0)
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prepend = 1;
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if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
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explicit_bzero(d, sizeof(d));
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return r;
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}
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explicit_bzero(d, sizeof(d));
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return 0;
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}
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int
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sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v)
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{
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int r, len_bits = BN_num_bits(v);
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size_t len_bytes = (len_bits + 7) / 8;
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u_char d[SSHBUF_MAX_BIGNUM], *dp;
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if (len_bits < 0 || len_bytes > SSHBUF_MAX_BIGNUM)
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return SSH_ERR_INVALID_ARGUMENT;
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if (BN_bn2bin(v, d) != (int)len_bytes)
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return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
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if ((r = sshbuf_reserve(buf, len_bytes + 2, &dp)) < 0) {
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explicit_bzero(d, sizeof(d));
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return r;
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}
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POKE_U16(dp, len_bits);
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if (len_bytes != 0)
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memcpy(dp + 2, d, len_bytes);
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explicit_bzero(d, sizeof(d));
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return 0;
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}
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#ifdef OPENSSL_HAS_ECC
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int
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sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
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{
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u_char d[SSHBUF_MAX_ECPOINT];
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BN_CTX *bn_ctx;
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size_t len;
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int ret;
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if ((bn_ctx = BN_CTX_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
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NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
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BN_CTX_free(bn_ctx);
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return SSH_ERR_INVALID_ARGUMENT;
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}
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if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
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d, len, bn_ctx) != len) {
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BN_CTX_free(bn_ctx);
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return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
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}
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BN_CTX_free(bn_ctx);
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ret = sshbuf_put_string(buf, d, len);
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explicit_bzero(d, len);
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return ret;
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}
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int
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sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
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{
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return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
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EC_KEY_get0_group(v));
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}
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#endif /* OPENSSL_HAS_ECC */
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