ref: 98c1cd7ae022efe276123898af6b892eade0732c
dir: /third_party/boringssl/src/crypto/evp/p_rsa.c/
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project 2006.
*/
/* ====================================================================
* Copyright (c) 2006 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* licensing@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com). */
#include <openssl/evp.h>
#include <limits.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include <openssl/rsa.h>
#include "../internal.h"
#include "../fipsmodule/rsa/internal.h"
#include "internal.h"
typedef struct {
// Key gen parameters
int nbits;
BIGNUM *pub_exp;
// RSA padding mode
int pad_mode;
// message digest
const EVP_MD *md;
// message digest for MGF1
const EVP_MD *mgf1md;
// PSS salt length
int saltlen;
// tbuf is a buffer which is either NULL, or is the size of the RSA modulus.
// It's used to store the output of RSA operations.
uint8_t *tbuf;
// OAEP label
uint8_t *oaep_label;
size_t oaep_labellen;
} RSA_PKEY_CTX;
typedef struct {
uint8_t *data;
size_t len;
} RSA_OAEP_LABEL_PARAMS;
static int pkey_rsa_init(EVP_PKEY_CTX *ctx) {
RSA_PKEY_CTX *rctx;
rctx = OPENSSL_malloc(sizeof(RSA_PKEY_CTX));
if (!rctx) {
return 0;
}
OPENSSL_memset(rctx, 0, sizeof(RSA_PKEY_CTX));
rctx->nbits = 2048;
rctx->pad_mode = RSA_PKCS1_PADDING;
rctx->saltlen = -2;
ctx->data = rctx;
return 1;
}
static int pkey_rsa_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) {
RSA_PKEY_CTX *dctx, *sctx;
if (!pkey_rsa_init(dst)) {
return 0;
}
sctx = src->data;
dctx = dst->data;
dctx->nbits = sctx->nbits;
if (sctx->pub_exp) {
dctx->pub_exp = BN_dup(sctx->pub_exp);
if (!dctx->pub_exp) {
return 0;
}
}
dctx->pad_mode = sctx->pad_mode;
dctx->md = sctx->md;
dctx->mgf1md = sctx->mgf1md;
dctx->saltlen = sctx->saltlen;
if (sctx->oaep_label) {
OPENSSL_free(dctx->oaep_label);
dctx->oaep_label = OPENSSL_memdup(sctx->oaep_label, sctx->oaep_labellen);
if (!dctx->oaep_label) {
return 0;
}
dctx->oaep_labellen = sctx->oaep_labellen;
}
return 1;
}
static void pkey_rsa_cleanup(EVP_PKEY_CTX *ctx) {
RSA_PKEY_CTX *rctx = ctx->data;
if (rctx == NULL) {
return;
}
BN_free(rctx->pub_exp);
OPENSSL_free(rctx->tbuf);
OPENSSL_free(rctx->oaep_label);
OPENSSL_free(rctx);
}
static int setup_tbuf(RSA_PKEY_CTX *ctx, EVP_PKEY_CTX *pk) {
if (ctx->tbuf) {
return 1;
}
ctx->tbuf = OPENSSL_malloc(EVP_PKEY_size(pk->pkey));
if (!ctx->tbuf) {
return 0;
}
return 1;
}
static int pkey_rsa_sign(EVP_PKEY_CTX *ctx, uint8_t *sig, size_t *siglen,
const uint8_t *tbs, size_t tbslen) {
RSA_PKEY_CTX *rctx = ctx->data;
RSA *rsa = ctx->pkey->pkey.rsa;
const size_t key_len = EVP_PKEY_size(ctx->pkey);
if (!sig) {
*siglen = key_len;
return 1;
}
if (*siglen < key_len) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
if (rctx->md) {
unsigned out_len;
switch (rctx->pad_mode) {
case RSA_PKCS1_PADDING:
if (!RSA_sign(EVP_MD_type(rctx->md), tbs, tbslen, sig, &out_len, rsa)) {
return 0;
}
*siglen = out_len;
return 1;
case RSA_PKCS1_PSS_PADDING:
return RSA_sign_pss_mgf1(rsa, siglen, sig, *siglen, tbs, tbslen,
rctx->md, rctx->mgf1md, rctx->saltlen);
default:
return 0;
}
}
return RSA_sign_raw(rsa, siglen, sig, *siglen, tbs, tbslen, rctx->pad_mode);
}
static int pkey_rsa_verify(EVP_PKEY_CTX *ctx, const uint8_t *sig,
size_t siglen, const uint8_t *tbs,
size_t tbslen) {
RSA_PKEY_CTX *rctx = ctx->data;
RSA *rsa = ctx->pkey->pkey.rsa;
if (rctx->md) {
switch (rctx->pad_mode) {
case RSA_PKCS1_PADDING:
return RSA_verify(EVP_MD_type(rctx->md), tbs, tbslen, sig, siglen, rsa);
case RSA_PKCS1_PSS_PADDING:
return RSA_verify_pss_mgf1(rsa, tbs, tbslen, rctx->md, rctx->mgf1md,
rctx->saltlen, sig, siglen);
default:
return 0;
}
}
size_t rslen;
const size_t key_len = EVP_PKEY_size(ctx->pkey);
if (!setup_tbuf(rctx, ctx) ||
!RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, siglen,
rctx->pad_mode) ||
rslen != tbslen ||
CRYPTO_memcmp(tbs, rctx->tbuf, rslen) != 0) {
return 0;
}
return 1;
}
static int pkey_rsa_verify_recover(EVP_PKEY_CTX *ctx, uint8_t *out,
size_t *out_len, const uint8_t *sig,
size_t sig_len) {
RSA_PKEY_CTX *rctx = ctx->data;
RSA *rsa = ctx->pkey->pkey.rsa;
const size_t key_len = EVP_PKEY_size(ctx->pkey);
if (out == NULL) {
*out_len = key_len;
return 1;
}
if (*out_len < key_len) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
if (rctx->md == NULL) {
return RSA_verify_raw(rsa, out_len, out, *out_len, sig, sig_len,
rctx->pad_mode);
}
if (rctx->pad_mode != RSA_PKCS1_PADDING) {
return 0;
}
// Assemble the encoded hash, using a placeholder hash value.
static const uint8_t kDummyHash[EVP_MAX_MD_SIZE] = {0};
const size_t hash_len = EVP_MD_size(rctx->md);
uint8_t *asn1_prefix;
size_t asn1_prefix_len;
int asn1_prefix_allocated;
if (!setup_tbuf(rctx, ctx) ||
!RSA_add_pkcs1_prefix(&asn1_prefix, &asn1_prefix_len,
&asn1_prefix_allocated, EVP_MD_type(rctx->md),
kDummyHash, hash_len)) {
return 0;
}
size_t rslen;
int ok = 1;
if (!RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, sig_len,
RSA_PKCS1_PADDING) ||
rslen != asn1_prefix_len ||
// Compare all but the hash suffix.
CRYPTO_memcmp(rctx->tbuf, asn1_prefix, asn1_prefix_len - hash_len) != 0) {
ok = 0;
}
if (asn1_prefix_allocated) {
OPENSSL_free(asn1_prefix);
}
if (!ok) {
return 0;
}
if (out != NULL) {
OPENSSL_memcpy(out, rctx->tbuf + rslen - hash_len, hash_len);
}
*out_len = hash_len;
return 1;
}
static int pkey_rsa_encrypt(EVP_PKEY_CTX *ctx, uint8_t *out, size_t *outlen,
const uint8_t *in, size_t inlen) {
RSA_PKEY_CTX *rctx = ctx->data;
RSA *rsa = ctx->pkey->pkey.rsa;
const size_t key_len = EVP_PKEY_size(ctx->pkey);
if (!out) {
*outlen = key_len;
return 1;
}
if (*outlen < key_len) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
if (!setup_tbuf(rctx, ctx) ||
!RSA_padding_add_PKCS1_OAEP_mgf1(rctx->tbuf, key_len, in, inlen,
rctx->oaep_label, rctx->oaep_labellen,
rctx->md, rctx->mgf1md) ||
!RSA_encrypt(rsa, outlen, out, *outlen, rctx->tbuf, key_len,
RSA_NO_PADDING)) {
return 0;
}
return 1;
}
return RSA_encrypt(rsa, outlen, out, *outlen, in, inlen, rctx->pad_mode);
}
static int pkey_rsa_decrypt(EVP_PKEY_CTX *ctx, uint8_t *out,
size_t *outlen, const uint8_t *in,
size_t inlen) {
RSA_PKEY_CTX *rctx = ctx->data;
RSA *rsa = ctx->pkey->pkey.rsa;
const size_t key_len = EVP_PKEY_size(ctx->pkey);
if (!out) {
*outlen = key_len;
return 1;
}
if (*outlen < key_len) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
size_t padded_len;
if (!setup_tbuf(rctx, ctx) ||
!RSA_decrypt(rsa, &padded_len, rctx->tbuf, key_len, in, inlen,
RSA_NO_PADDING) ||
!RSA_padding_check_PKCS1_OAEP_mgf1(
out, outlen, key_len, rctx->tbuf, padded_len, rctx->oaep_label,
rctx->oaep_labellen, rctx->md, rctx->mgf1md)) {
return 0;
}
return 1;
}
return RSA_decrypt(rsa, outlen, out, key_len, in, inlen, rctx->pad_mode);
}
static int check_padding_md(const EVP_MD *md, int padding) {
if (!md) {
return 1;
}
if (padding == RSA_NO_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PADDING_MODE);
return 0;
}
return 1;
}
static int is_known_padding(int padding_mode) {
switch (padding_mode) {
case RSA_PKCS1_PADDING:
case RSA_NO_PADDING:
case RSA_PKCS1_OAEP_PADDING:
case RSA_PKCS1_PSS_PADDING:
return 1;
default:
return 0;
}
}
static int pkey_rsa_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) {
RSA_PKEY_CTX *rctx = ctx->data;
switch (type) {
case EVP_PKEY_CTRL_RSA_PADDING:
if (!is_known_padding(p1) || !check_padding_md(rctx->md, p1) ||
(p1 == RSA_PKCS1_PSS_PADDING &&
0 == (ctx->operation & (EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY))) ||
(p1 == RSA_PKCS1_OAEP_PADDING &&
0 == (ctx->operation & EVP_PKEY_OP_TYPE_CRYPT))) {
OPENSSL_PUT_ERROR(EVP, EVP_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
return 0;
}
if ((p1 == RSA_PKCS1_PSS_PADDING || p1 == RSA_PKCS1_OAEP_PADDING) &&
rctx->md == NULL) {
rctx->md = EVP_sha1();
}
rctx->pad_mode = p1;
return 1;
case EVP_PKEY_CTRL_GET_RSA_PADDING:
*(int *)p2 = rctx->pad_mode;
return 1;
case EVP_PKEY_CTRL_RSA_PSS_SALTLEN:
case EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN:
if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PSS_SALTLEN);
return 0;
}
if (type == EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN) {
*(int *)p2 = rctx->saltlen;
} else {
if (p1 < -2) {
return 0;
}
rctx->saltlen = p1;
}
return 1;
case EVP_PKEY_CTRL_RSA_KEYGEN_BITS:
if (p1 < 256) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_KEYBITS);
return 0;
}
rctx->nbits = p1;
return 1;
case EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP:
if (!p2) {
return 0;
}
BN_free(rctx->pub_exp);
rctx->pub_exp = p2;
return 1;
case EVP_PKEY_CTRL_RSA_OAEP_MD:
case EVP_PKEY_CTRL_GET_RSA_OAEP_MD:
if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PADDING_MODE);
return 0;
}
if (type == EVP_PKEY_CTRL_GET_RSA_OAEP_MD) {
*(const EVP_MD **)p2 = rctx->md;
} else {
rctx->md = p2;
}
return 1;
case EVP_PKEY_CTRL_MD:
if (!check_padding_md(p2, rctx->pad_mode)) {
return 0;
}
rctx->md = p2;
return 1;
case EVP_PKEY_CTRL_GET_MD:
*(const EVP_MD **)p2 = rctx->md;
return 1;
case EVP_PKEY_CTRL_RSA_MGF1_MD:
case EVP_PKEY_CTRL_GET_RSA_MGF1_MD:
if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING &&
rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_MGF1_MD);
return 0;
}
if (type == EVP_PKEY_CTRL_GET_RSA_MGF1_MD) {
if (rctx->mgf1md) {
*(const EVP_MD **)p2 = rctx->mgf1md;
} else {
*(const EVP_MD **)p2 = rctx->md;
}
} else {
rctx->mgf1md = p2;
}
return 1;
case EVP_PKEY_CTRL_RSA_OAEP_LABEL: {
if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PADDING_MODE);
return 0;
}
OPENSSL_free(rctx->oaep_label);
RSA_OAEP_LABEL_PARAMS *params = p2;
rctx->oaep_label = params->data;
rctx->oaep_labellen = params->len;
return 1;
}
case EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL:
if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PADDING_MODE);
return 0;
}
CBS_init((CBS *)p2, rctx->oaep_label, rctx->oaep_labellen);
return 1;
default:
OPENSSL_PUT_ERROR(EVP, EVP_R_COMMAND_NOT_SUPPORTED);
return 0;
}
}
static int pkey_rsa_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
RSA *rsa = NULL;
RSA_PKEY_CTX *rctx = ctx->data;
if (!rctx->pub_exp) {
rctx->pub_exp = BN_new();
if (!rctx->pub_exp || !BN_set_word(rctx->pub_exp, RSA_F4)) {
return 0;
}
}
rsa = RSA_new();
if (!rsa) {
return 0;
}
if (!RSA_generate_key_ex(rsa, rctx->nbits, rctx->pub_exp, NULL)) {
RSA_free(rsa);
return 0;
}
EVP_PKEY_assign_RSA(pkey, rsa);
return 1;
}
const EVP_PKEY_METHOD rsa_pkey_meth = {
EVP_PKEY_RSA,
pkey_rsa_init,
pkey_rsa_copy,
pkey_rsa_cleanup,
pkey_rsa_keygen,
pkey_rsa_sign,
NULL /* sign_message */,
pkey_rsa_verify,
NULL /* verify_message */,
pkey_rsa_verify_recover,
pkey_rsa_encrypt,
pkey_rsa_decrypt,
NULL /* derive */,
NULL /* paramgen */,
pkey_rsa_ctrl,
};
int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int padding) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_RSA_PADDING,
padding, NULL);
}
int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *out_padding) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_GET_RSA_PADDING,
0, out_padding);
}
int EVP_PKEY_CTX_set_rsa_pss_keygen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md) {
return 0;
}
int EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen(EVP_PKEY_CTX *ctx, int salt_len) {
return 0;
}
int EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md(EVP_PKEY_CTX *ctx,
const EVP_MD *md) {
return 0;
}
int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int salt_len) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
(EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY),
EVP_PKEY_CTRL_RSA_PSS_SALTLEN, salt_len, NULL);
}
int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *out_salt_len) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
(EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY),
EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN, 0, out_salt_len);
}
int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int bits) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
EVP_PKEY_CTRL_RSA_KEYGEN_BITS, bits, NULL);
}
int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *e) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP, 0, e);
}
int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_RSA_OAEP_MD, 0, (void *)md);
}
int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **out_md) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_GET_RSA_OAEP_MD, 0, (void*) out_md);
}
int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_RSA_MGF1_MD, 0, (void*) md);
}
int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **out_md) {
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_GET_RSA_MGF1_MD, 0, (void*) out_md);
}
int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, uint8_t *label,
size_t label_len) {
RSA_OAEP_LABEL_PARAMS params = {label, label_len};
return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_RSA_OAEP_LABEL, 0, ¶ms);
}
int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx,
const uint8_t **out_label) {
CBS label;
if (!EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL, 0, &label)) {
return -1;
}
if (CBS_len(&label) > INT_MAX) {
OPENSSL_PUT_ERROR(EVP, ERR_R_OVERFLOW);
return -1;
}
*out_label = CBS_data(&label);
return (int)CBS_len(&label);
}