openssl3.2 - exp - export RSA pubKey from RSA privKey on memory
概述
官方给的例子(openssl3.2 - 官方demo学习 - encode - rsa_encode.c)是基于文件操作的.文章来源：https://www.toymoban.com/news/detail-838443.html
我的工程只需要openssl 操作内存数据, 改了一个操作buffer的版本.
从内存中的RSA私钥数据, 导出RSA公钥来用.文章来源地址https://www.toymoban.com/news/detail-838443.html
笔记
/*!
* \file main.cpp
* \note openssl3.2 - exp - export RSA pubKey from RSA privKey on memory
*/
#include "my_openSSL_lib.h"
#include <openssl/crypto.h>
#include <openssl/bio.h>
#include <openssl/decoder.h>
#include <openssl/encoder.h>
#include <openssl/evp.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include "CMemHookRec.h"
// 为了内存操作, 已经将私钥数据文件转成了数组, 嵌入到工程中
//! \ref https://lostspeed.blog.csdn.net/article/details/136486115
//! 数组为 const char ucAry_priv_key_for_test[1892];
#include "priv_key_for_test.h"
#include <cassert>
void my_openssl_app();
// 都是在操作内存, 从内存中的私钥数据, 转出到内存中的公钥数据
bool exportRsaPrivKeyToRsaPubKey(const char* pBufPrivKey, int lenPrivKey, const char* pBufPrivKeyPwd, char*& pBufPubKey, int& lenPubKey);
EVP_PKEY* load_key(OSSL_LIB_CTX* libctx, const char* pBufPrivKey, int lenPrivKey, const char* passphrase);
bool export_Key(EVP_PKEY* pkey, const char* passphrase, char*& pBufPubKey, int& lenPubKey);
int main(int argc, char** argv)
{
setvbuf(stdout, NULL, _IONBF, 0); // 清掉stdout缓存, 防止调用printf时阻塞
mem_hook();
my_openssl_app();
mem_unhook();
/*! run result
b_rc = true
the rsa public key is below:
0000 - 2d 2d 2d 2d 2d 42 45 47-49 4e 20 52 53 41 20 50 -----BEGIN RSA P
0010 - 55 42 4c 49 43 20 4b 45-59 2d 2d 2d 2d 2d 0a 4d UBLIC KEY-----.M
0020 - 49 49 42 43 67 4b 43 41-51 45 41 6f 6a 62 54 2f IIBCgKCAQEAojbT/
0030 - 64 71 79 63 6b 2f 34 58-4a 79 54 45 45 49 34 63 dqyck/4XJyTEEI4c
0040 - 51 76 77 49 33 6b 66 76-38 46 78 30 46 50 75 6b QvwI3kfv8Fx0FPuk
0050 - 53 41 6d 77 71 52 66 44-6b 55 46 57 57 4b 4c 0a SAmwqRfDkUFWWKL.
0060 - 7a 67 4a 6b 71 38 66 58-76 65 51 66 31 74 55 32 zgJkq8fXveQf1tU2
0070 - 32 71 50 70 51 69 6b 30-79 64 6a 75 59 55 35 75 2qPpQik0ydjuYU5u
0080 - 47 41 45 34 68 36 64 45-36 66 45 75 79 75 7a 6e GAE4h6dE6fEuyuzn
0090 - 4a 43 32 4b 4b 51 47 55-76 74 71 52 6c 77 76 49 JC2KKQGUvtqRlwvI
00a0 - 0a 2b 66 78 77 53 54 4d-45 2f 54 68 48 57 59 71 .+fxwSTME/ThHWYq
00b0 - 43 41 76 58 5a 2f 49 52-4d 31 32 37 66 67 37 4a CAvXZ/IRM127fg7J
00c0 - 37 61 59 37 74 31 65 68-79 79 33 57 59 50 72 71 7aY7t1ehyy3WYPrq
00d0 - 44 37 45 4c 78 75 37 6c-5a 65 36 4b 54 6f 50 59 D7ELxu7lZe6KToPY
00e0 - 2b 0a 70 52 58 54 35 62-61 59 37 52 44 66 54 4c +.pRXT5baY7RDfTL
00f0 - 78 7a 76 31 54 68 63 4c-30 46 72 4b 32 70 62 6c xzv1ThcL0FrK2pbl
0100 - 31 59 48 32 30 31 58 57-67 6c 2b 46 51 62 31 6a 1YH201XWgl+FQb1j
0110 - 70 41 51 75 4d 53 58 76-79 52 4a 56 79 69 6d 76 pAQuMSXvyRJVyimv
0120 - 36 2b 0a 48 6e 67 6a 37-35 63 57 74 54 42 30 49 6+.Hngj75cWtTB0I
0130 - 43 33 68 52 57 55 69 74-77 56 6c 43 4b 6f 76 61 C3hRWUitwVlCKova
0140 - 57 54 63 43 49 4f 33 48-55 56 55 70 58 4a 78 4f WTcCIO3HUVUpXJxO
0150 - 73 51 71 63 34 58 46 2f-70 67 6e 4c 72 79 75 41 sQqc4XF/pgnLryuA
0160 - 74 34 37 0a 71 56 6a 63-45 61 2f 42 58 68 38 75 t47.qVjcEa/BXh8u
0170 - 79 6b 49 2b 30 34 6e 4e-58 79 34 66 6d 76 4a 48 ykI+04nNXy4fmvJH
0180 - 4a 55 54 45 30 51 49 44-41 51 41 42 0a 2d 2d 2d JUTE0QIDAQAB.---
0190 - 2d 2d 45 4e 44 20 52 53-41 20 50 55 42 4c 49 43 --END RSA PUBLIC
01a0 - 20 4b 45 59 2d 2d 2d 2d-2d 0a KEY-----.
free map, g_mem_hook_map.size() = 0
*/
return 0;
}
void my_openssl_app()
{
bool b_rc = false;
char* pszPubKey = NULL;
int lenPubKey = 0;
BIO* bio_out = BIO_new_fp(stdout, 0);
assert(NULL != bio_out);
do {
// PWD_PRIV_KEY 是一个宏 char*, 定义在 priv_key_for_test.h 中, 是私钥数据的口令
// 一般私钥数据做好时, 都是有口令的
b_rc = exportRsaPrivKeyToRsaPubKey(ucAry_priv_key_for_test, sizeof(ucAry_priv_key_for_test), PWD_PRIV_KEY, pszPubKey, lenPubKey);
BIO_printf(bio_out, "b_rc = %s\n", (b_rc ? "true" : "false"));
if (!b_rc)
{
assert(false);
break;
}
// now can use pszPubKey
BIO_printf(bio_out, "the rsa public key is below:\n");
BIO_dump_fp(stdout, pszPubKey, lenPubKey);
} while (false);
if (NULL != pszPubKey)
{
OPENSSL_free(pszPubKey);
pszPubKey = NULL;
}
if (NULL != bio_out)
{
BIO_free(bio_out);
bio_out = NULL;
}
}
bool exportRsaPrivKeyToRsaPubKey(const char* pBufPrivKey, int lenPrivKey, const char* pBufPrivKeyPwd, char*& pBufPubKey, int& lenPubKey)
{
bool b_rc = false;
EVP_PKEY* pubKey = NULL;
do {
// 如果ras私钥是没有口令保护的, 可以不给口令
if ((NULL == pBufPrivKey) || (lenPrivKey <= 0))
{
break;
}
pubKey = load_key(NULL, pBufPrivKey, lenPrivKey, pBufPrivKeyPwd);
if (NULL == pubKey)
{
break;
}
if (!export_Key(pubKey, NULL, pBufPubKey, lenPubKey))
{
break;
}
b_rc = true;
} while (false);
if (NULL != pubKey)
{
EVP_PKEY_free(pubKey);
pubKey = NULL;
}
return b_rc;
}
EVP_PKEY* load_key(OSSL_LIB_CTX* libctx, const char* pBufPrivKey, int lenPrivKey, const char* passphrase)
{
int ret = 0;
EVP_PKEY* pkey = NULL;
OSSL_DECODER_CTX* dctx = NULL;
int selection = 0;
int i_tmp = 0;
BIO* bio_privKey = BIO_new(BIO_s_mem());
if (NULL == bio_privKey)
{
goto cleanup;
}
i_tmp = BIO_write(bio_privKey, pBufPrivKey, lenPrivKey);
if (i_tmp != lenPrivKey)
{
goto cleanup;
}
/*
* Create PEM decoder context expecting an RSA key.
*
* For raw (non-PEM-encoded) keys, change "PEM" to "DER".
*
* The selection argument here specifies whether we are willing to accept a
* public key, private key, or either. If it is set to zero, either will be
* accepted. If set to EVP_PKEY_KEYPAIR, a private key will be required, and
* if set to EVP_PKEY_PUBLIC_KEY, a public key will be required.
*/
dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "PEM", NULL, "RSA",
selection,
libctx, NULL);
if (dctx == NULL) {
// fprintf(stderr, "OSSL_DECODER_CTX_new_for_pkey() failed\n");
goto cleanup;
}
/*
* Set passphrase if provided; needed to decrypt encrypted PEM files.
* If the input is not encrypted, any passphrase provided is ignored.
*
* Alternative methods for specifying passphrases exist, such as a callback
* (see OSSL_DECODER_CTX_set_passphrase_cb(3)), which may be more useful for
* interactive applications which do not know if a passphrase should be
* prompted for in advance, or for GUI applications.
*/
if (passphrase != NULL) {
if (OSSL_DECODER_CTX_set_passphrase(dctx,
(const unsigned char*)passphrase,
strlen(passphrase)) == 0) {
// fprintf(stderr, "OSSL_DECODER_CTX_set_passphrase() failed\n");
goto cleanup;
}
}
/* Do the decode, reading from file. */
if (OSSL_DECODER_from_bio(dctx, bio_privKey) == 0) { // 如果f是stdin, 就需要自己输入私钥内容, 所以函数入参的f必须是一个实际文件的FILE*
// fprintf(stderr, "OSSL_DECODER_from_fp() failed\n");
goto cleanup;
}
ret = 1;
cleanup:
OSSL_DECODER_CTX_free(dctx);
/*
* pkey is created by OSSL_DECODER_CTX_new_for_pkey, but we
* might fail subsequently, so ensure it's properly freed
* in this case.
*/
if (ret == 0) {
EVP_PKEY_free(pkey);
pkey = NULL;
}
if (NULL != bio_privKey)
{
BIO_free(bio_privKey);
bio_privKey = NULL;
}
return pkey;
}
bool export_Key(EVP_PKEY* pkey, const char* passphrase, char*& pBufPubKey, int& lenPubKey)
{
int ret = 0;
int selection;
OSSL_ENCODER_CTX* ectx = NULL;
unsigned char* pdata = NULL;
size_t sz_len_data = 0;
/*
* Create a PEM encoder context.
*
* For raw (non-PEM-encoded) output, change "PEM" to "DER".
*
* The selection argument controls whether the private key is exported
* (EVP_PKEY_KEYPAIR), or only the public key (EVP_PKEY_PUBLIC_KEY). The
* former will fail if we only have a public key.
*
* Note that unlike the decode API, you cannot specify zero here.
*
* Purely for the sake of demonstration, here we choose to export the whole
* key if a passphrase is provided and the public key otherwise.
*/
// 如果给出口令, 就导出公私钥对;
// 如果不给口令, 就只导出公钥
// 实际应用中, 我们就只有导出公钥的需求
selection = (passphrase != NULL)
? EVP_PKEY_KEYPAIR
: EVP_PKEY_PUBLIC_KEY;
ectx = OSSL_ENCODER_CTX_new_for_pkey(pkey, selection, "PEM", NULL, NULL);
if (ectx == NULL) {
// fprintf(stderr, "OSSL_ENCODER_CTX_new_for_pkey() failed\n");
goto cleanup;
}
/*
* Set passphrase if provided; the encoded output will then be encrypted
* using the passphrase.
*
* Alternative methods for specifying passphrases exist, such as a callback
* (see OSSL_ENCODER_CTX_set_passphrase_cb(3), just as for OSSL_DECODER_CTX;
* however you are less likely to need them as you presumably know whether
* encryption is desired in advance.
*
* Note that specifying a passphrase alone is not enough to cause the
* key to be encrypted. You must set both a cipher and a passphrase.
*/
if (passphrase != NULL) {
/* Set cipher. AES-128-CBC is a reasonable default. */
if (OSSL_ENCODER_CTX_set_cipher(ectx, "AES-128-CBC", NULL) == 0) {
// fprintf(stderr, "OSSL_ENCODER_CTX_set_cipher() failed\n");
goto cleanup;
}
/* Set passphrase. */
if (OSSL_ENCODER_CTX_set_passphrase(ectx,
(const unsigned char*)passphrase,
strlen(passphrase)) == 0) {
// fprintf(stderr, "OSSL_ENCODER_CTX_set_passphrase() failed\n");
goto cleanup;
}
}
/* Do the encode, writing to the given file. */
if (OSSL_ENCODER_to_data(ectx, &pdata, &sz_len_data) == 0) {
// fprintf(stderr, "OSSL_ENCODER_to_fp() failed\n");
goto cleanup;
}
pBufPubKey = (char*)pdata;
lenPubKey = (int)sz_len_data;
ret = 1;
cleanup:
OSSL_ENCODER_CTX_free(ectx);
return ret;
}
END
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