Some notable changes, from upstream's release notes: - sshd(8): Remove support for obsolete "host/port" syntax. - ssh(1): When prompting whether to record a new host key, accept the key fingerprint as a synonym for "yes". - ssh-keygen(1): when acting as a CA and signing certificates with an RSA key, default to using the rsa-sha2-512 signature algorithm. - ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa" (RSA/SHA1) algorithm from those accepted for certificate signatures. - ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F support to provide address-space isolation for token middleware libraries (including the internal one). - ssh(1): this release enables UpdateHostkeys by default subject to some conservative preconditions. - scp(1): this release changes the behaviour of remote to remote copies (e.g. "scp host-a:/path host-b:") to transfer through the local host by default. - scp(1): experimental support for transfers using the SFTP protocol as a replacement for the venerable SCP/RCP protocol that it has traditionally used. Additional integration work is needed to support FIDO/U2F in the base system. Deprecation Notice ------------------ OpenSSH will disable the ssh-rsa signature scheme by default in the next release. Reviewed by: imp MFC after: 1 month Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D29985
186 lines
4.9 KiB
C
186 lines
4.9 KiB
C
/* $OpenBSD: ssh-xmss.c,v 1.4 2020/10/19 22:49:23 dtucker Exp $*/
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/*
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* Copyright (c) 2017 Stefan-Lukas Gazdag.
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* Copyright (c) 2017 Markus Friedl.
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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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#include "includes.h"
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#ifdef WITH_XMSS
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#define SSHKEY_INTERNAL
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#include <sys/types.h>
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#include <limits.h>
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#include <string.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include "log.h"
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#include "sshbuf.h"
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#include "sshkey.h"
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#include "sshkey-xmss.h"
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#include "ssherr.h"
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#include "ssh.h"
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#include "xmss_fast.h"
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int
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ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
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const u_char *data, size_t datalen, u_int compat)
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{
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u_char *sig = NULL;
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size_t slen = 0, len = 0, required_siglen;
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unsigned long long smlen;
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int r, ret;
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struct sshbuf *b = NULL;
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if (lenp != NULL)
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*lenp = 0;
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if (sigp != NULL)
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*sigp = NULL;
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if (key == NULL ||
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sshkey_type_plain(key->type) != KEY_XMSS ||
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key->xmss_sk == NULL ||
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sshkey_xmss_params(key) == NULL)
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return SSH_ERR_INVALID_ARGUMENT;
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if ((r = sshkey_xmss_siglen(key, &required_siglen)) != 0)
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return r;
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if (datalen >= INT_MAX - required_siglen)
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return SSH_ERR_INVALID_ARGUMENT;
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smlen = slen = datalen + required_siglen;
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if ((sig = malloc(slen)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_xmss_get_state(key, 1)) != 0)
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goto out;
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if ((ret = xmss_sign(key->xmss_sk, sshkey_xmss_bds_state(key), sig, &smlen,
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data, datalen, sshkey_xmss_params(key))) != 0 || smlen <= datalen) {
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r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */
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goto out;
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}
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/* encode signature */
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if ((b = sshbuf_new()) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if ((r = sshbuf_put_cstring(b, "ssh-xmss@openssh.com")) != 0 ||
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(r = sshbuf_put_string(b, sig, smlen - datalen)) != 0)
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goto out;
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len = sshbuf_len(b);
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if (sigp != NULL) {
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if ((*sigp = malloc(len)) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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memcpy(*sigp, sshbuf_ptr(b), len);
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}
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if (lenp != NULL)
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*lenp = len;
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/* success */
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r = 0;
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out:
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if ((ret = sshkey_xmss_update_state(key, 1)) != 0) {
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/* discard signature since we cannot update the state */
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if (r == 0 && sigp != NULL && *sigp != NULL) {
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explicit_bzero(*sigp, len);
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free(*sigp);
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}
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if (sigp != NULL)
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*sigp = NULL;
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if (lenp != NULL)
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*lenp = 0;
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r = ret;
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}
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sshbuf_free(b);
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if (sig != NULL)
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freezero(sig, slen);
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return r;
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}
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int
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ssh_xmss_verify(const struct sshkey *key,
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const u_char *signature, size_t signaturelen,
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const u_char *data, size_t datalen, u_int compat)
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{
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struct sshbuf *b = NULL;
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char *ktype = NULL;
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const u_char *sigblob;
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u_char *sm = NULL, *m = NULL;
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size_t len, required_siglen;
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unsigned long long smlen = 0, mlen = 0;
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int r, ret;
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if (key == NULL ||
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sshkey_type_plain(key->type) != KEY_XMSS ||
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key->xmss_pk == NULL ||
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sshkey_xmss_params(key) == NULL ||
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signature == NULL || signaturelen == 0)
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return SSH_ERR_INVALID_ARGUMENT;
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if ((r = sshkey_xmss_siglen(key, &required_siglen)) != 0)
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return r;
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if (datalen >= INT_MAX - required_siglen)
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return SSH_ERR_INVALID_ARGUMENT;
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if ((b = sshbuf_from(signature, signaturelen)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 ||
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(r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0)
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goto out;
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if (strcmp("ssh-xmss@openssh.com", ktype) != 0) {
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r = SSH_ERR_KEY_TYPE_MISMATCH;
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goto out;
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}
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if (sshbuf_len(b) != 0) {
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r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
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goto out;
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}
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if (len != required_siglen) {
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r = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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if (datalen >= SIZE_MAX - len) {
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r = SSH_ERR_INVALID_ARGUMENT;
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goto out;
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}
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smlen = len + datalen;
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mlen = smlen;
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if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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memcpy(sm, sigblob, len);
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memcpy(sm+len, data, datalen);
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if ((ret = xmss_sign_open(m, &mlen, sm, smlen,
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key->xmss_pk, sshkey_xmss_params(key))) != 0) {
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debug2_f("xmss_sign_open failed: %d", ret);
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}
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if (ret != 0 || mlen != datalen) {
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r = SSH_ERR_SIGNATURE_INVALID;
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goto out;
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}
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/* XXX compare 'm' and 'data' ? */
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/* success */
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r = 0;
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out:
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if (sm != NULL)
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freezero(sm, smlen);
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if (m != NULL)
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freezero(m, smlen);
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sshbuf_free(b);
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free(ktype);
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return r;
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}
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#endif /* WITH_XMSS */
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