openssl3.2 - exp - zlib

概述

客户端和服务端进行数据交换时，如果压缩一下要交互的数据，可以节省带宽。
如果数据是文本型, 压缩率特别大。

以前用zlib库单独实验过，写起来还挺麻烦的。

正好这次已经将zlib特性加入了openssl(openssl3.2 - 编译 - zlib.dll不要使用绝对路径), 试一下用openssl来压缩/解压缩数据方便不？

笔记

命令行实现

// openssl zip help
openssl zlib --help// zip
openssl zlib -e -in test.txt -out test.txt.zlib -pass pass:my_pwd// unzip
openssl zlib -d -in test.txt.zlib -out test.txt.zlib.unzlib -pass pass:my_pwd

程序实现

先看一下openssl.exe的实现

备注 - 压缩时无法base64

如果选了zlib, 就不能选base64.
如果想zlib后，再base64, 需要单独对输出结果进行base64(https://lostspeed.blog.csdn.net/article/details/136881319).

		if (do_zlib)base64 = 0;

压缩时无法带口令压缩

压缩时口令不起作用，因为可以不带口令解开。

openssl zlib -d -in test.txt.zlib -out test.txt.zlib.unzlib

如果想将压缩后的内容加密，需要自己单独对压缩后的内容加密。

实现 - 对buffer进行压缩和解压缩

测试效果

org:
0000 - 68 65 6c 6c 6f 20 6f 70-65 6e 73 73 6c 33 2e 32   hello openssl3.2
0010 - 20 7a 6c 69 62 0a                                  zlib.
zip:
0000 - 78 9c cb 48 cd c9 c9 57-c8 2f 48 cd 2b 2e ce 31   x..H...W./H.+..1
0010 - d6 33 52 a8 ca c9 4c e2-02 00 5e 4e 07 a7         .3R...L...^N..
unzip:
0000 - 68 65 6c 6c 6f 20 6f 70-65 6e 73 73 6c 33 2e 32   hello openssl3.2
0010 - 20 7a 6c 69 62 0a                                  zlib.
free mem_hook map, g_mem_hook_map.size() = 0, no openssl API call memory leak

工程实现

test prj is exp034_zlib

main.cpp

/*!
* \file main.cpp
*/#include "ossl/my_openSSL_lib_v1.1.h"
#include <openssl/crypto.h>
#include <openssl/bio.h>#include <stdlib.h>
#include <stdio.h>
#include <assert.h>#include "COsslZlibBuffer.h"void my_openssl_app();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();return 0;
}void my_openssl_app()
{bool b_rc = false;int i_rc = 0;COsslZlibBuffer zlib;uint8_t szBuf[0x1000];int lenBuf = 0;uint8_t* pBufOut1 = NULL;int lenBufOut1 = 0;uint8_t* pBufOut2 = NULL;int lenBufOut2 = 0;strcpy((char*)szBuf, "hello openssl3.2 zlib\n");lenBuf = strlen((char*)szBuf);printf("org:\n");BIO_dump_fp(stdout, szBuf, lenBuf);b_rc = zlib.zip(szBuf, lenBuf, pBufOut1, lenBufOut1);assert(b_rc);printf("zip:\n");BIO_dump_fp(stdout, pBufOut1, lenBufOut1);b_rc = zlib.unzip(pBufOut1, lenBufOut1, pBufOut2, lenBufOut2);assert(b_rc);printf("unzip:\n");BIO_dump_fp(stdout, pBufOut2, lenBufOut2);assert(lenBufOut2 == lenBuf);i_rc = memcmp(szBuf, pBufOut2, lenBuf);assert(0 == i_rc);if (NULL != pBufOut1){OPENSSL_free(pBufOut1);pBufOut1 = NULL;}if (NULL != pBufOut2){OPENSSL_free(pBufOut2);pBufOut2 = NULL;}
}

COsslZlibBuffer.h

//! \file COsslZlibBuffer.h#ifndef __C_OSSL_ZLIB_BUFFER_H__
#define __C_OSSL_ZLIB_BUFFER_H__#include <stdlib.h>
#include <stdio.h>
#include <cstdint> // for uint8_t#ifndef IN
#define IN
#endif // !IN#ifndef OUT
#define OUT
#endif // !OUT#include "openssl/bio.h"class COsslZlibBuffer
{
public:COsslZlibBuffer();virtual ~COsslZlibBuffer();// 出参指针调用者负责释放(OPENSSL_free())bool zip(IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut);bool unzip(IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut);private:bool zipOpt(bool isZip, IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut);size_t bio_get_length(BIO* bio);bool bio_to_buf(BIO* bio, uint8_t*& pBuf, int& lenBuf);
};#endif // #ifndef __C_OSSL_ZLIB_BUFFER_H__

COsslZlibBuffer.cpp

//! \file COsslZlibBuffer.cpp#include "COsslZlibBuffer.h"#include "openssl/bio.h"
#include "openssl/comp.h"COsslZlibBuffer::COsslZlibBuffer()
{}COsslZlibBuffer::~COsslZlibBuffer()
{}bool COsslZlibBuffer::zip(IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut)
{return zipOpt(true, pBuf, lenBuf, pBufOut, lenBufOut);
}bool COsslZlibBuffer::unzip(IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut)
{return zipOpt(false, pBuf, lenBuf, pBufOut, lenBufOut);
}bool COsslZlibBuffer::zipOpt(bool isZip, IN uint8_t* pBuf, IN int lenBuf, OUT uint8_t*& pBufOut, OUT int& lenBufOut)
{bool b_rc = false;BIO* bio_zip = NULL;BIO* bio_in = NULL;BIO* bio_out = NULL;BIO* bio_read = NULL;BIO* bio_write = NULL;uint8_t szBuf[0x1000];int iCntRead = 0;int iCntWasWrite = 0;do {if ((NULL == pBuf) || (lenBuf <= 0)){break;}lenBufOut = 0;bio_zip = BIO_new(BIO_f_zlib());if (NULL == bio_zip){break;}bio_in = BIO_new_mem_buf(pBuf, lenBuf);if (NULL == bio_in){break;}bio_out = BIO_new(BIO_s_mem());if (NULL == bio_out){break;}if (isZip){bio_read = bio_in;bio_write = BIO_push(bio_zip, bio_out);  // write to bio link header, out form bio link tail}else {bio_read = BIO_push(bio_zip, bio_in);bio_write = bio_out;}do {iCntRead = BIO_read(bio_read, szBuf, (int)sizeof(szBuf));if (iCntRead <= 0){break;}iCntWasWrite = BIO_write(bio_write, szBuf, iCntRead);if (iCntWasWrite != iCntRead){goto END;}} while (true);if (!BIO_flush(bio_write)){break;}// 如果读bio_write, 得到的是写入的数据, 而不是处理完的输出数据if (!bio_to_buf(bio_out, pBufOut, lenBufOut)){break;}/*do_zlib = 1;enc = 1;saltlen = PKCS5_SALT_LEN;dgst = (EVP_MD *)EVP_sha256();iter = 1;if (do_zlib)base64 = 0;BIO *bzl = NULL;bzl = BIO_new(BIO_f_zlib()wbio = BIO_push(bzl, wbio);while (BIO_pending(rbio) || !BIO_eof(rbio)) {inl = BIO_read(rbio, (char *)buff, bsize);if (inl <= 0)break;if (!streamable && !BIO_eof(rbio)) {//	BIO_printf(bio_err, "Unstreamable cipher mode\n");//	goto end;//}//if (BIO_write(wbio, (char*)buff, inl) != inl) {//	BIO_printf(bio_err, "error writing output file\n");//	goto end;//}//if (!streamable)//break;//	}BIO_flush(wbio)if (enc)wbio = BIO_push(bzl, wbio);elserbio = BIO_push(bzl, rbio);*/b_rc = true;} while (false);END:if (NULL != bio_read){BIO_free_all(bio_read);bio_read = NULL;}if (NULL != bio_write){BIO_free_all(bio_write);bio_write = NULL;}return b_rc;
}size_t COsslZlibBuffer::bio_get_length(BIO* bio)
{size_t bio_length = 0;do {if (NULL == bio){break;}// BIO_seek(bio, 0);bio_length = BIO_ctrl_pending(bio);} while (false);return bio_length;
}bool COsslZlibBuffer::bio_to_buf(BIO* bio, uint8_t*& pBuf, int& lenBuf)
{bool b_rc = false;int i_rc = 0;do {if (NULL == bio){break;}lenBuf = (int)bio_get_length(bio);pBuf = (uint8_t*)OPENSSL_malloc(lenBuf + 1);if (NULL == pBuf){break;}pBuf[lenBuf] = '\0';i_rc = BIO_read(bio, pBuf, lenBuf);BIO_seek(bio, 0); // ! 读完了, 将数据读指针恢复.b_rc = (i_rc == lenBuf);} while (false);return b_rc;
}

总结

用openssl做zip操作比直接用zlib库操作方便多了。
openssl的封装真优秀。

备注 - 解压可以替代完整性校验

	// 测试zip内容变了之后，是否还能正常解压？// 实验过了, 随便改一个字节，都无法解压成功pBufOut1[lenBufOut1 / 2 - 1] = pBufOut1[lenBufOut1 /2 - 1] + 1;b_rc = zlib.unzip(pBufOut1, lenBufOut1, pBufOut3, lenBufOut3);assert(b_rc);

实验过了, 将压缩后的内容随便改一个字节(头部附近，尾部附近，内容中部附近)，再解压都会失败。
如果这样的话，那就不用特意做hash来确认内容是否被无意中修改。

备注 - 多次压缩没作用

在第一次压缩后，尝试将压缩结果再压缩，长度反而增加了一点。
说明一次压缩就够了。

备注 - 和7zip的压缩性能的比较

		// 因为样本比较小(2816字节), 用7zip分别极限压缩成.7z和.zip, 好不多少// .zip = 1526字节// .7zip = 1481字节// 算了，就用openssl3.2自带的zip压缩吧// 用openssl自带的zip操作(2816 => 1391), 比7zip的极限压缩还优秀..., 惊讶

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