2a7b6f3908
[skip ci] Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7814)
248 lines
7.7 KiB
C
248 lines
7.7 KiB
C
/*
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* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <stdio.h>
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#include "internal/cryptlib.h"
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#include <openssl/bn.h>
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#include <openssl/rsa.h>
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#include <openssl/objects.h>
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#include <openssl/x509.h>
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#include "internal/x509_int.h"
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#include "rsa_locl.h"
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/* Size of an SSL signature: MD5+SHA1 */
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#define SSL_SIG_LENGTH 36
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/*
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* encode_pkcs1 encodes a DigestInfo prefix of hash |type| and digest |m|, as
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* described in EMSA-PKCS1-v1_5-ENCODE, RFC 3447 section 9.2 step 2. This
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* encodes the DigestInfo (T and tLen) but does not add the padding.
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*
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* On success, it returns one and sets |*out| to a newly allocated buffer
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* containing the result and |*out_len| to its length. The caller must free
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* |*out| with |OPENSSL_free|. Otherwise, it returns zero.
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*/
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static int encode_pkcs1(unsigned char **out, int *out_len, int type,
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const unsigned char *m, unsigned int m_len)
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{
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X509_SIG sig;
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X509_ALGOR algor;
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ASN1_TYPE parameter;
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ASN1_OCTET_STRING digest;
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uint8_t *der = NULL;
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int len;
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sig.algor = &algor;
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sig.algor->algorithm = OBJ_nid2obj(type);
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if (sig.algor->algorithm == NULL) {
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RSAerr(RSA_F_ENCODE_PKCS1, RSA_R_UNKNOWN_ALGORITHM_TYPE);
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return 0;
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}
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if (OBJ_length(sig.algor->algorithm) == 0) {
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RSAerr(RSA_F_ENCODE_PKCS1,
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RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
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return 0;
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}
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parameter.type = V_ASN1_NULL;
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parameter.value.ptr = NULL;
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sig.algor->parameter = ¶meter;
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sig.digest = &digest;
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sig.digest->data = (unsigned char *)m;
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sig.digest->length = m_len;
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len = i2d_X509_SIG(&sig, &der);
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if (len < 0)
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return 0;
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*out = der;
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*out_len = len;
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return 1;
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}
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int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
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unsigned char *sigret, unsigned int *siglen, RSA *rsa)
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{
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int encrypt_len, encoded_len = 0, ret = 0;
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unsigned char *tmps = NULL;
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const unsigned char *encoded = NULL;
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if (rsa->meth->rsa_sign) {
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return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa);
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}
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/* Compute the encoded digest. */
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if (type == NID_md5_sha1) {
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/*
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* NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
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* earlier. It has no DigestInfo wrapper but otherwise is
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* RSASSA-PKCS1-v1_5.
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*/
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if (m_len != SSL_SIG_LENGTH) {
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RSAerr(RSA_F_RSA_SIGN, RSA_R_INVALID_MESSAGE_LENGTH);
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return 0;
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}
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encoded_len = SSL_SIG_LENGTH;
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encoded = m;
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} else {
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if (!encode_pkcs1(&tmps, &encoded_len, type, m, m_len))
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goto err;
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encoded = tmps;
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}
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if (encoded_len > RSA_size(rsa) - RSA_PKCS1_PADDING_SIZE) {
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RSAerr(RSA_F_RSA_SIGN, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
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goto err;
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}
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encrypt_len = RSA_private_encrypt(encoded_len, encoded, sigret, rsa,
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RSA_PKCS1_PADDING);
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if (encrypt_len <= 0)
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goto err;
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*siglen = encrypt_len;
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ret = 1;
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err:
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OPENSSL_clear_free(tmps, (size_t)encoded_len);
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return ret;
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}
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/*
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* int_rsa_verify verifies an RSA signature in |sigbuf| using |rsa|. It may be
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* called in two modes. If |rm| is NULL, it verifies the signature for digest
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* |m|. Otherwise, it recovers the digest from the signature, writing the digest
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* to |rm| and the length to |*prm_len|. |type| is the NID of the digest
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* algorithm to use. It returns one on successful verification and zero
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* otherwise.
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*/
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int int_rsa_verify(int type, const unsigned char *m, unsigned int m_len,
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unsigned char *rm, size_t *prm_len,
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const unsigned char *sigbuf, size_t siglen, RSA *rsa)
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{
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int decrypt_len, ret = 0, encoded_len = 0;
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unsigned char *decrypt_buf = NULL, *encoded = NULL;
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if (siglen != (size_t)RSA_size(rsa)) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_WRONG_SIGNATURE_LENGTH);
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return 0;
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}
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/* Recover the encoded digest. */
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decrypt_buf = OPENSSL_malloc(siglen);
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if (decrypt_buf == NULL) {
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RSAerr(RSA_F_INT_RSA_VERIFY, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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decrypt_len = RSA_public_decrypt((int)siglen, sigbuf, decrypt_buf, rsa,
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RSA_PKCS1_PADDING);
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if (decrypt_len <= 0)
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goto err;
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if (type == NID_md5_sha1) {
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/*
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* NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
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* earlier. It has no DigestInfo wrapper but otherwise is
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* RSASSA-PKCS1-v1_5.
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*/
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if (decrypt_len != SSL_SIG_LENGTH) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
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goto err;
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}
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if (rm != NULL) {
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memcpy(rm, decrypt_buf, SSL_SIG_LENGTH);
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*prm_len = SSL_SIG_LENGTH;
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} else {
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if (m_len != SSL_SIG_LENGTH) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
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goto err;
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}
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if (memcmp(decrypt_buf, m, SSL_SIG_LENGTH) != 0) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
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goto err;
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}
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}
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} else if (type == NID_mdc2 && decrypt_len == 2 + 16
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&& decrypt_buf[0] == 0x04 && decrypt_buf[1] == 0x10) {
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/*
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* Oddball MDC2 case: signature can be OCTET STRING. check for correct
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* tag and length octets.
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*/
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if (rm != NULL) {
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memcpy(rm, decrypt_buf + 2, 16);
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*prm_len = 16;
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} else {
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if (m_len != 16) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
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goto err;
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}
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if (memcmp(m, decrypt_buf + 2, 16) != 0) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
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goto err;
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}
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}
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} else {
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/*
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* If recovering the digest, extract a digest-sized output from the end
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* of |decrypt_buf| for |encode_pkcs1|, then compare the decryption
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* output as in a standard verification.
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*/
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if (rm != NULL) {
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const EVP_MD *md = EVP_get_digestbynid(type);
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if (md == NULL) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_UNKNOWN_ALGORITHM_TYPE);
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goto err;
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}
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m_len = EVP_MD_size(md);
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if (m_len > (size_t)decrypt_len) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_DIGEST_LENGTH);
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goto err;
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}
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m = decrypt_buf + decrypt_len - m_len;
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}
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/* Construct the encoded digest and ensure it matches. */
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if (!encode_pkcs1(&encoded, &encoded_len, type, m, m_len))
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goto err;
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if (encoded_len != decrypt_len
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|| memcmp(encoded, decrypt_buf, encoded_len) != 0) {
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RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
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goto err;
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}
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/* Output the recovered digest. */
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if (rm != NULL) {
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memcpy(rm, m, m_len);
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*prm_len = m_len;
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}
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}
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ret = 1;
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err:
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OPENSSL_clear_free(encoded, (size_t)encoded_len);
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OPENSSL_clear_free(decrypt_buf, siglen);
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return ret;
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}
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int RSA_verify(int type, const unsigned char *m, unsigned int m_len,
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const unsigned char *sigbuf, unsigned int siglen, RSA *rsa)
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{
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if (rsa->meth->rsa_verify) {
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return rsa->meth->rsa_verify(type, m, m_len, sigbuf, siglen, rsa);
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}
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return int_rsa_verify(type, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
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}
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