openssl3.2 - exp - base64 / unbase64

概述

想将2进制内容放到配置文件中, 作为配置项的值.
那先base64一下, 变成可见字符串后再写入配置文件.

先看了官方的命令行实现.
然后从官方命令行实现, 迁移出一个调用openssl API来干活的版本.

自己测试迁移后的版本时, 细节还是挺多, 不像记录官方实现那么容易.
对BIO_push()的使用有了进一步的认识.

笔记

命令行实现

// 做实验用的明文
echo this is pt > pt.txt// base64帮助
openssl base64 --help// base64 明文编码
openssl base64 -e -in pt.txt -out pt.txt.base64// 查看编码后的密文
more pt.txt.base64// base64 密文解码
openssl base64 -d -in pt.txt.base64 -out pt.txt.base64.unbase64// 查看解码后的明文
more pt.txt.base64.unbase64

程序实现

/*!
* \file exp033_base64.cpp
* \note openssl3.2 - exp - base64 / unbase64
* 用BIO链来完成base64/unbase64
*/#include "my_openSSL_lib.h"
#include <openssl/crypto.h>
#include <openssl/bio.h>#include <stdlib.h>
#include <stdio.h>
#include <assert.h>#include "CMemHookRec.h"#include <openssl/evp.h>void my_openssl_app();
bool base64(bool isEncode, UCHAR* pucBufIn, int lenBufIn, UCHAR*& pucBufOut, int& lenBufOut);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 resultbuffer original0000 - 00 01 02 03 04 05 06 07-08 09 0a 0b 0c            .............after base640000 - 41 41 45 43 41 77 51 46-42 67 63 49 43 51 6f 4c   AAECAwQFBgcICQoL0010 - 44 41 3d 3d 0a                                    DA==.after unbase640000 - 00 01 02 03 04 05 06 07-08 09 0a 0b 0c            .............ok : the same by org and unbase64free map, g_mem_hook_map.size() = 0D:\my_dev\my_local_git_prj\study\openSSL\exp\exp033_base64\x64\Debug\exp033_base64.exe (进程 305792)已退出，代码为 0。要在调试停止时自动关闭控制台，请启用“工具”->“选项”->“调试”->“调试停止时自动关闭控制台”。按任意键关闭此窗口. . .*/return 0;
}void my_openssl_app()
{int i = 0;UCHAR ucBuf[0x10 - 3];UCHAR* pucBufOut = NULL;int iLenBufOut = 0;UCHAR* pucBufOut1 = NULL;int iLenBufOut1 = 0;for (i = 0; i < sizeof(ucBuf); i++){ucBuf[i] = (UCHAR)i;}printf("buffer original\n");BIO_dump_fp(stdout, ucBuf, sizeof(ucBuf));do {if (!base64(true, ucBuf, sizeof(ucBuf), pucBufOut, iLenBufOut)){assert(false);break;}printf("after base64\n");BIO_dump_fp(stdout, pucBufOut, iLenBufOut);if (!base64(false, pucBufOut, iLenBufOut, pucBufOut1, iLenBufOut1)){assert(false);break;}printf("after unbase64\n");BIO_dump_fp(stdout, pucBufOut1, iLenBufOut1);if (iLenBufOut1 != sizeof(ucBuf)){assert(false);break;}if (0 != memcmp(ucBuf, pucBufOut1, sizeof(ucBuf))){assert(false);break;}printf("ok : the same by org and unbase64\n");} while (false);if (NULL != pucBufOut){OPENSSL_free(pucBufOut);pucBufOut = NULL;}if (NULL != pucBufOut1){OPENSSL_free(pucBufOut1);pucBufOut1 = NULL;}
}bool base64(bool isEncode, UCHAR* pucBufIn, int lenBufIn, UCHAR*& pucBufOut, int& lenBufOut)
{bool b_rc = false;BIO* bio_container = NULL;BIO* bio_to_base64 = NULL;BIO* bio_header = NULL; // BIO链头BIO* bio_tail = NULL; // BIO链尾BIO* bio_to_write = NULL; // 将数据写入的BIO指针BIO* bio_read_from = NULL; // 将数据读出的BIO指针size_t sz_wt = 0;size_t sz_rd = 0;int i_rc = 0;int len = 0;do {pucBufOut = NULL;lenBufOut = 0;if ((NULL == pucBufIn) || (lenBufIn <= 0)){break;}bio_container = BIO_new(BIO_s_mem());if (NULL == bio_container){break;}bio_to_base64 = BIO_new(BIO_f_base64());if (NULL == bio_to_base64){break;}bio_header = BIO_push(bio_to_base64, bio_container);bio_tail = bio_container;if (isEncode){bio_to_write = bio_header;bio_read_from = bio_tail;}else {bio_to_write = bio_tail;bio_read_from = bio_header;}i_rc = BIO_write_ex(bio_to_write, pucBufIn, lenBufIn, &sz_wt);if ((1 != i_rc) || (lenBufIn != sz_wt)){break;}BIO_flush(bio_to_write); // 数据写完后, 必须对写入的BIO执行 BIO_flush.// 必须从bio_read_from读取处理完的数据长度, 才是处理之后的数据长度len = BIO_pending(bio_read_from); // 必须BIO_flush()之后, 才能读取到BIO内可以读出的数据长度. 否则读出的长度是0// 当解码时, 得到的处理完的长度还是没解码之前的长度, 不过不影响// 拿这个长度开buffer, 实际数据处理完的长度按照从bio_read_from()中累计出的数据长度为准// 将处理过的数据从bio_header中读出来pucBufOut = (UCHAR*)OPENSSL_malloc(len + 1); // 再多加1个字节的空间, 便于观察得到的可见字符串if (NULL == pucBufOut){break;}pucBufOut[len] = '\0';do {// 不能从bio_header读取, 因为读取后, 还是原来的数据长度i_rc = BIO_read_ex(bio_read_from, pucBufOut + lenBufOut, len - lenBufOut, &sz_rd);if (i_rc <= 0){// 多次读, 直到读空了, 不算错break;}lenBufOut += sz_rd;} while (true);b_rc = true;} while (false);if (NULL != bio_header){BIO_free_all(bio_header);bio_header = NULL;}return b_rc;
}

END