Otherwise unintended results could happen. For example, Coverity reports a division by zero in qcrypto_afsplit_hash. While this cannot really happen, it shows that the contract of qcrypto_hash_digest_len can be improved. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
220 lines
6 KiB
C
220 lines
6 KiB
C
/*
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* QEMU Crypto hash algorithms
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "crypto/hash.h"
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#ifdef CONFIG_GNUTLS_HASH
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#include <gnutls/gnutls.h>
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#include <gnutls/crypto.h>
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#endif
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static size_t qcrypto_hash_alg_size[QCRYPTO_HASH_ALG__MAX] = {
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[QCRYPTO_HASH_ALG_MD5] = 16,
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[QCRYPTO_HASH_ALG_SHA1] = 20,
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[QCRYPTO_HASH_ALG_SHA256] = 32,
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};
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size_t qcrypto_hash_digest_len(QCryptoHashAlgorithm alg)
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{
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assert(alg < G_N_ELEMENTS(qcrypto_hash_alg_size));
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return qcrypto_hash_alg_size[alg];
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}
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#ifdef CONFIG_GNUTLS_HASH
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static int qcrypto_hash_alg_map[QCRYPTO_HASH_ALG__MAX] = {
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[QCRYPTO_HASH_ALG_MD5] = GNUTLS_DIG_MD5,
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[QCRYPTO_HASH_ALG_SHA1] = GNUTLS_DIG_SHA1,
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[QCRYPTO_HASH_ALG_SHA256] = GNUTLS_DIG_SHA256,
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};
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gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg)
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{
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if (alg < G_N_ELEMENTS(qcrypto_hash_alg_map)) {
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return true;
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}
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return false;
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}
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int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
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const struct iovec *iov,
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size_t niov,
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uint8_t **result,
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size_t *resultlen,
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Error **errp)
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{
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int i, ret;
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gnutls_hash_hd_t dig;
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if (alg >= G_N_ELEMENTS(qcrypto_hash_alg_map)) {
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error_setg(errp,
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"Unknown hash algorithm %d",
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alg);
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return -1;
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}
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ret = gnutls_hash_init(&dig, qcrypto_hash_alg_map[alg]);
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if (ret < 0) {
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error_setg(errp,
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"Unable to initialize hash algorithm: %s",
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gnutls_strerror(ret));
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return -1;
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}
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for (i = 0; i < niov; i++) {
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ret = gnutls_hash(dig, iov[i].iov_base, iov[i].iov_len);
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if (ret < 0) {
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error_setg(errp,
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"Unable process hash data: %s",
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gnutls_strerror(ret));
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goto error;
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}
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}
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ret = gnutls_hash_get_len(qcrypto_hash_alg_map[alg]);
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if (ret <= 0) {
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error_setg(errp,
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"Unable to get hash length: %s",
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gnutls_strerror(ret));
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goto error;
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}
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if (*resultlen == 0) {
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*resultlen = ret;
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*result = g_new0(uint8_t, *resultlen);
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} else if (*resultlen != ret) {
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error_setg(errp,
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"Result buffer size %zu is smaller than hash %d",
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*resultlen, ret);
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goto error;
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}
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gnutls_hash_deinit(dig, *result);
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return 0;
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error:
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gnutls_hash_deinit(dig, NULL);
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return -1;
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}
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#else /* ! CONFIG_GNUTLS_HASH */
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gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg G_GNUC_UNUSED)
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{
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return false;
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}
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int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
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const struct iovec *iov G_GNUC_UNUSED,
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size_t niov G_GNUC_UNUSED,
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uint8_t **result G_GNUC_UNUSED,
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size_t *resultlen G_GNUC_UNUSED,
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Error **errp)
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{
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error_setg(errp,
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"Hash algorithm %d not supported without GNUTLS",
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alg);
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return -1;
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}
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#endif /* ! CONFIG_GNUTLS_HASH */
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int qcrypto_hash_bytes(QCryptoHashAlgorithm alg,
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const char *buf,
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size_t len,
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uint8_t **result,
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size_t *resultlen,
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Error **errp)
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{
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struct iovec iov = { .iov_base = (char *)buf,
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.iov_len = len };
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return qcrypto_hash_bytesv(alg, &iov, 1, result, resultlen, errp);
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}
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static const char hex[] = "0123456789abcdef";
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int qcrypto_hash_digestv(QCryptoHashAlgorithm alg,
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const struct iovec *iov,
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size_t niov,
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char **digest,
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Error **errp)
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{
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uint8_t *result = NULL;
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size_t resultlen = 0;
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size_t i;
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if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
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return -1;
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}
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*digest = g_new0(char, (resultlen * 2) + 1);
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for (i = 0 ; i < resultlen ; i++) {
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(*digest)[(i * 2)] = hex[(result[i] >> 4) & 0xf];
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(*digest)[(i * 2) + 1] = hex[result[i] & 0xf];
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}
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(*digest)[resultlen * 2] = '\0';
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g_free(result);
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return 0;
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}
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int qcrypto_hash_digest(QCryptoHashAlgorithm alg,
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const char *buf,
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size_t len,
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char **digest,
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Error **errp)
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{
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struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
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return qcrypto_hash_digestv(alg, &iov, 1, digest, errp);
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}
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int qcrypto_hash_base64v(QCryptoHashAlgorithm alg,
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const struct iovec *iov,
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size_t niov,
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char **base64,
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Error **errp)
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{
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uint8_t *result = NULL;
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size_t resultlen = 0;
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if (qcrypto_hash_bytesv(alg, iov, niov, &result, &resultlen, errp) < 0) {
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return -1;
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}
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*base64 = g_base64_encode(result, resultlen);
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g_free(result);
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return 0;
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}
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int qcrypto_hash_base64(QCryptoHashAlgorithm alg,
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const char *buf,
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size_t len,
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char **base64,
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Error **errp)
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{
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struct iovec iov = { .iov_base = (char *)buf, .iov_len = len };
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return qcrypto_hash_base64v(alg, &iov, 1, base64, errp);
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}
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